論文 - 西　宏章

pvFed: Personalized Vertical Federated learning for Client-Specific Tasks

Nishikawa A., Yanabe T., Sakuma Y., Okuda Y., Nishi H.

IEEJ Transactions on Electrical and Electronic Engineering （IEEJ Transactions on Electrical and Electronic Engineering）  19 （ 6 ） 993 - 1000 2024年06月

ISSN  19314973

　概要を見る

Federated Learning (FL) is a distributed machine learning paradigm that enables multiple data holders to collaborate on building machine learning models while preserving the privacy of their data. FL can be categorized as horizontal or vertical, depending on the distribution characteristics of the data. Specifically, horizontal FL uses data partitioned in the sample space, whereas vertical FL uses data partitioned in the feature space. Traditional vertical FL methods aim to facilitate collaboration among clients to infer a single global target. However, these methods may be impractical because each client often has a unique target to be inferred. In this paper, we propose a novel vertical FL method, called personalized vertical federated learning (pvFed), which addresses this limitation by allowing each client to perform inferences specific to their individual task. To the best of our knowledge, no existing method currently addresses this limitation. The objective of pvFed is to construct a global model that generates a representation vector to support client inference. The global model, constructed using distillation and dimensionality reduction, takes a sample ID common to all clients as input and outputs a sample-specific representation vector. Clients utilize the intermediate representation of their own model and the representation vectors output by the global model for inference. Because these vectors are not dependent on client-specific tasks, clients can repurpose them for any additional tasks. Our experiments, conducted on two distinct data types—image and tabular data sets, under a vertical partitioning where each client had its own specific task, demonstrated the efficacy of vectors generated by the global model in pvFed for client inference. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

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FPGA Live Migration of Content-Based Anonymization Mechanism with Network Consistency

Toyohara T., Yamamoto K., Nishi H.

IEEJ Transactions on Electrical and Electronic Engineering （IEEJ Transactions on Electrical and Electronic Engineering）  19 （ 4 ） 507 - 517 2024年04月

ISSN  19314973

　概要を見る

In smart communities, data are aggregated, and various services are provided based on it. When considering the optimization of service delivery through cooperative processing between the edge and the cloud in smart communities, it is essential to realize network transparent edge services due to the constraints of not touching end devices in order to improve user convenience and additional cost reduction. Moreover, considering the minimization of service provision and service delivery latency at the edge, it is desirable to use field-programmable gate arrays (FPGAs), which have lower power consumption, lower latency, and higher throughput than conventional processors. Additionally, to advance towards even lower latency, the distribution of processing load is important, and service migration is necessary for this purpose. Service migration is generally used to increase service availability, and even for edge services, service migration is important because the distribution of processing and the location where the service should be provided changes over time due to user mobility. When considering network transparency, service migration should be performed on the communication path between the end device and the cloud. Furthermore, to enhance service transparency, it is essential to maintain communication consistency for continuous service provision and minimize service downtime. Therefore, this study proposes a migration mechanism with FPGAs to satisfy these requirements. As an example of a real application, we target a network-transparent data anonymization application to protect the privacy of data providers and evaluate the proposed architecture based on the reality of latency and other factors. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

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Network-Transparent Service Container and Migration with Information Distribution Management in Edge Environments

Namba Y., Shimahara S., Nishi H.

ACM International Conference Proceeding Series    23 - 28 2024年01月

　概要を見る

Smart communities use myriad IoT devices and the data they transmit to perform global optimization. In network-transparent service provision, data transmitted from IoT devices are analyzed using network devices such as switches and routers in the edge region to add value to the data without modifying the IoT devices. However, to establish a mechanism for providing such network transparency services while complying with the opt-in or opt-out of data provided by users, data distribution management is necessary to determine the stored location and path of the target data. In addition, because a smart community environment is assumed to be a heterogeneous computing-resource environment, it is necessary to envision a dynamic relocation function for transparent network services considering the usage of computing resources. In this study, we proposed a method for managing and migrating transparent network services deployed on edge nodes using containers and linked it to an existing information distribution management mechanism that enables data distribution management at the service level. In the experiments, we confirmed that dynamic placement was possible under a load. We also measured the response delay associated with the provision of a transparent network service and confirmed that the associated processing delay was approximately 10 ms.

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Preface

Li Y., Nishi H., Pang P.

ACM International Conference Proceeding Series 2024年01月

Anonymity‐Aware Framework for Designing Recommender Systems

M Honda, H Nishi

IEEJ Transactions on Electrical and Electronic Engineering 2024年

Anonymity-Aware Framework for Designing Recommender Systems

Honda M., Nishi H.

IEEJ Transactions on Electrical and Electronic Engineering （IEEJ Transactions on Electrical and Electronic Engineering）  19 （ 9 ） 1455 - 1464 2024年

ISSN  19314973

　概要を見る

Due to increasing secondary use of data, recommender systems using anonymized data are in demand. However, implementing a recommender system requires complicated data processing and programming, and the relationship between anonymization level and recommendation quality has not been investigated. Therefore, this study proposes a framework that facilitates the development of recommender systems. Additionally, a method is proposed for quantitatively evaluating recommendation quality when the anonymization level is varied. The proposed method promotes data utilization by recommender systems and determination of compensation for providing data based on anonymization level. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

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FPGA Live Migration of Content‐Based Anonymization Mechanism with Network Consistency

T Toyohara, K Yamamoto, H Nishi

IEEJ Transactions on Electrical and Electronic Engineering 19 (4), 507-517 2024年

pvFed: Personalized Vertical Federated learning for Client‐Specific Tasks

A Nishikawa, T Yanabe, Y Sakuma, Y Okuda, H Nishi

IEEJ Transactions on Electrical and Electronic Engineering 2024年

Proceedings of the 2024 7th International Conference on Software Engineering and Information Management, ICSIM 2024, Suva, Fiji, January 23-25, 2024

ICSIM （ACM）  2024年

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Proposal of Differential Privacy Anonymization for IoT Applications Using MQTT Broker

Morise K., Toyohara T., Nishi H.

Proceedings - IEEE Consumer Communications and Networking Conference, CCNC    634 - 635 2024年

ISSN  23319860

　概要を見る

IoT applications require secure communication methods that protect personal information contained in communication data. This study focuses on MQTT, a low-cost protocol used for IoT communication, and proposes a mechanism to anonymize communication data between IoT and clients. MQTT is a publish-subscribe model of communication where a broker handles many-to-many communications among clients. Due to the concentration of communications on the broker, it is efficient to anonymize data there. Therefore, the proposed mechanism performs differential privacy anonymization of communication data on the MQTT broker. We also propose a mechanism to anonymize data according to anonymization criteria required by senders and receivers using topic names and user properties, which are features of MQTT. We implemented the proposed mechanism in an FPGA-based MQTT broker and confirmed that it achieves the same throughput and low latency as regular MQTT communication and satisfies IoT applications such as power control and automated driving that require sub-millisecond latency.

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Practical Trajectory Anonymization Method Using Latent Space Generalization

Sakuma Y., Nishi H.

IEEJ Transactions on Electrical and Electronic Engineering 2024年

ISSN  19314973

　概要を見る

The global positioning system (GPS) data are commonly used for location-based services such as traffic flow prediction. However, such data contain considerable sensitive information and thus, they must be anonymized before being published. In this study, we investigate trajectory anonymization. Previous methods have limitations in that they cannot be applied for different load network sparseness and cannot preserve the trajectory information. Thus, we propose a DNN-based method that can anonymize trajectories with different load network sparseness and also preserve the trajectory information. Specifically, the trajectories are projected to the latent space using the pre-trained encoder-decoder model, and the latent variables are generalized. Furthermore, to reduce the information loss, we propose a segment-aware trajectory modeling and study the effectiveness of assuming the normal distribution to the latent space. The experimental results using real GPS data show the effectiveness of the proposed method, presenting the improvement in the data reservation rate by approximately 3% and reducing the reconstruction error by approximately 31%. © 2024 The Author(s). IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

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Network-Transparent Load Balancing and Migration for Edge Computing

Namba Y., Morishima R., Nishi H.

Proceedings - IEEE Consumer Communications and Networking Conference, CCNC    228 - 233 2024年

ISSN  23319860

　概要を見る

The network infrastructure in a smart community uses the cloud and compute servers, and the edge and fog areas to perform processing in the optimal place. Nodes in the edge and fog areas have various processing capacities, and there must be load-balancing mechanisms to meet the requirements of applications. However, Internet of Things (IoT) devices are generally small, computationally constrained, and numerous, so reconfiguration and functionality updates for the network must be kept to a minimum. In addition, if nodes establish connections with other nodes to exchange their information, the number of connections will be large, and communication costs will be high. In this study, we use nodes called 'Distributor' that can monitor data flow through the network without changing the existing infrastructure. Piggyback technique is used to add information onto the packets flowing in the network. Distributors add the information to the packets and exchange information to each other without establishing connections with other nodes, and they perform load balancing based on the information. By changing and migrating the processing locations among Distributors, IoT devices can continue to communicate with other nodes even during load balancing. Experiments confirmed that load balancing could be performed to prepare for sudden load increases and that the impact of piggybacking on occupied bandwidth and processing delay was 0.177% and 0.06%, respectively. We also confirmed that sensor data can be sent without reconnecting communications, even during load balancing.

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Accelerator for Trajectory Anonymization Using Map Matching

Nakano H., Yamamoto K., Nishi H.

IEEE Access 12   152277 - 152288 2024年

ISSN  2169-3536

　概要を見る

This study is focused on hardware-based anonymization of location data for addressing privacy concerns while maintaining data utility in applications such as traffic-congestion prediction. The anonymization process involves approximating user location data to map intersections, identifying trajectories, and applying k-anonymization. However, the processing time in software implementation should be minimized. For real-time services, the process must be completed within 30 s to 1 min, which corresponds to the information update interval. Service requirements cannot be met when the volume of data and the scale of maps increase. To address this issue, we implemented a hardware accelerator on an field programmable gate array to perform the process with the aim of reducing the processing time. As a result, the maximum throughput of the proposed mechanism was approximately 150,000 data/s, which surpasses the target value of 130,000 data/s. The data retention rate, which represents information loss, was approximately 90% for the commonly used range of 10≤ k≤ 20. The difference in the data retention rate compared with the software implementation was approximately 1%. These results confirmed the effectiveness of the anonymization results obtained using the proposed mechanism.

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A Low-Code Development Platform for Industrialized Insect-based Bioconversion Systems

Pang C., Liang J., Yu G., Zhang J., Nishi H., Wang K.I.K., Li Z., Dai W., Vyatkin V.

IEEE International Symposium on Industrial Electronics 2024年

ISSN  21635137

　概要を見る

Industrialized insect-based bioconversion is a technologically promising and economical viable approach for solving global crisis of food security and waste management. The successful implementation of such a multi-disciplinary system requires comprehensive expertise and skills from biotechnology, automation, information, and circular economy domains. This is rather difficult for existing practitioners. To simplify their jobs, by leveraging recent advances in industrial informatics, this work proposed and developed a low-code development platform for engineering the automation logic of industrial insect rearing and processing. For feasibility demonstration, a pilot facility has been designed, deployed, and benchmarked in this work. When compared with the conventional pro-code practice, the proposed low-code approach can significantly reduce development costs, shorten delivery times, and improve communication efficiency.

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Access Control Management System for Edge Computing Environment Using Tag-Based Matching and Cache Injection

Shimahara S., Nohara M., Nishi H.

IEEJ Transactions on Electrical and Electronic Engineering （IEEJ Transactions on Electrical and Electronic Engineering）  18 （ 9 ） 1472 - 1481 2023年09月

ISSN  19314973

　概要を見る

With increasing attention to the secondary use of data, privacy protection laws such as the General Data Protection Regulation (GDPR) and California Consumer Privacy Act (CCPA) have come into force to protect residents from unauthorized exploitation of personal data. Flow management is an effective method to track the distribution of user data in a multi-domain network environment. Transparency in the relationship between data and service providers is essential to track the status of data provision. Vendor and Consumer Relationship Management (VCRM) manages this relationship by regulating relevant flow information. VCRM is expected to collaborate with the edge-computing environment in the management of regional unit flow, wherein all access to personal user data should be restricted in accordance with the stakeholders' requests. Accordingly, this study proposes a packet processing function that collaborates with VCRM to manage the access control of flows passing through a regional network. Moreover, this paper proposes methods to reduce packet processing time on the switch, and requests to the switch controller. Using tag-based matching and cache injection methods, the number of requests to the controller decreased to 33.4% of the original figure. Our proposed method also reduces the total processing time on flow management switches in the network environment in the analysis of encrypted TCP streams such as HTTP over TLS and MQTT over TLS. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

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COVID-19 mRNA vaccination status and concerns among pregnant women in Japan: a multicenter questionnaire survey

Takahashi, K; Samura, O; Hasegawa, A; Okubo, H; Morimoto, K; Horiya, M; Okamoto, A; Ochiai, D; Tanaka, M; Sekiguchi, M; Miyasaka, N; Suzuki, Y; Tabata, T; Hayata, E; Nakata, M; Suzuki, T; Nishi, H; Toda, Y; Tanigaki, S; Furuya, N; Hasegawa, J; Tamaru, S; Kamei, Y; Sayama, S; Nagamatsu, T; Takahashi, YO; Kitagawa, M; Arakaki, T; Sekizawa, A

BMC PREGNANCY AND CHILDBIRTH 23 （ 1 ）  2023年05月

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Anthropometric measurements of term singletons at 6 years of age born from fresh and frozen embryo transfer: A multicenter prospective study in Japan

Ueno, K, Kojima, J, Suzuki, K, Kuwahara, A, Higuchi, Y, Tanaka, A, Utsunomiya, T, Mio, Y, Nishi, H, Yoshimura, Y, Irahara, M, Kuji, N

REPRODUCTIVE MEDICINE AND BIOLOGY 22 （ 1 ）  2023年01月

ISSN  1445-5781

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有用性保持を目的とした多次元データとしての経路情報匿名化

佐久間， 結子， 岩井， 智夢， 西川， 誠人， 西宏章

AIC カンファレンス予稿集, 55-55 2023年

マルチチャンネル音源を使用した異常音検知・分離・音源同定手法の提案と大型冷凍機を用いた評価

西川， 誠人， 服部， 一裕， 田中， 基雅， 村並， 広章， 西宏章

AIC カンファレンス予稿集, 59-59 2023年

スマートシティ情報インフラは FPGA を求めるか?-スマートシティをやるなら FPGA が必要といわせたい

西宏章

研究報告システムと LSI の設計技術 (SLDM) 2023 (5), 1-1 2023年

スマートコミュニティで必要となる計算機システムとは?-スマートシティをスマートたらしめる計算機システム

西宏章

研究報告システム・アーキテクチャ (ARC) 2023 (5), 1-1 2023年

Can we say

H Nishi

IEICE Technical Report; IEICE Tech. Rep. 122 (354), 24-24 2023年

Access Control Management System for Edge Computing Environment Using Tag‐Based Matching and Cache Injection

S Shimahara, M Nohara, H Nishi

IEEJ Transactions on Electrical and Electronic Engineering 18 (9), 1472-1481 2023年

Privacy-Preserving Hierarchical Anonymization Framework over Encrypted Data

Jia, J. and Saito, K. and Nishi, H.

arXiv （一般社団法人 電気学会）  abs/2310.12401 （ 10 ） 1011 - 1019 2023年

ISSN  23318422

　概要を見る

Smart cities, which can monitor the real world and provide smart services in a variety of fields, have improved people’s living standards as urbanization has accelerated. However, there are security and privacy concerns because smart city applications collect large amounts of privacy-sensitive information from people and their social circles. Anonymization, which generalizes data and reduces data uniqueness, is an important step in preserving the privacy of sensitive information. However, anonymization methods frequently require large datasets and rely on untrusted third parties to collect and manage data, particularly in a cloud environment. In this case, private data leakage remains a critical issue, discouraging users from sharing their data and impeding the advancement of smart city services. This problem can be solved if the computational entity performs anonymization without obtaining the original plain text. This study proposed a hierarchical k-anonymization framework using homomorphic encryption and secret sharing composed of two types of domains. Different computing methods are selected flexibly, and two domains are connected hierarchically to obtain higher-level anonymization results efficiently. The experimental results show that connecting two domains can accelerate the anonymization process, indicating that the proposed secure hierarchical architecture is practical and efficient.

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• CiNii Research

Proposal and implementation of k-anonymization method for data insertion and deletion

Han K., Nishi H.

IEEE International Symposium on Industrial Electronics 2023-June   1 - 6 2023年

　概要を見る

Preserving the privacy of individuals while publishing their relevant data has been an important issue. K-anonymization, which is one of the most useful privacy models, is valid for static data; however, it does not support dynamic data updating. In this paper, we propose a method for inserting and deleting data into and from k-anonymous tabular data while maintaining k-anonymity. This method ensures k-anonymity after multiple publications by retaining the raw data and the latest published data. In the deletion process, the specified record is first deleted from the data table, and the records remaining in the q∗-block to which the specified record belonged are inserted into the data table excluding the remaining records. This insertion of multiple records is performed by repeating the above addition process in sequence.

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Layer-7 and 5-Tuple Information Analysis Framework for Providing Positional Flexibility In Location Determination for Service Provision

Sato Y., Namba Y., Nishi H.

IECON Proceedings (Industrial Electronics Conference)    1 - 6 2023年

ISSN  21624704

　概要を見る

In a smart community, which is an initiative to create an efficient regional society by leveraging information and communications technology (ICT), various data exchanges and data processing are performed. Owing to the demand for network transparency in data processing, packet rewriting is required at network edges. In the packet rewriting process, packets need to be analyzed after obtaining the necessary permissions. A conventional method for packet analysis is using a 5-tuple. While this method can analyze packets by a service user, it cannot analyze packets by a service. Moreover, service provision needs to take place at the appropriate locations with respect to the privacy level, and service provision locations need to be flexible enough to change even subsequent to the commencement of services. To address this issue, there is a need to enable positional flexibility in determining the location for service provision between the data source and cloud. In this study, assuming that the permission to analyze packets had been obtained within the smart community, we implemented a framework that could analyze not only 5-tuple but also layer-7 (L7) information and rewrite packet contents based on the analysis results. The process performed at the edge first analyzed the header of the incoming packet to determine whether the packet was subject to L7 information analysis. If the packet was subject to analysis, the L7 information was analyzed to determine whether the packet was subject to rewriting. A packet subject to rewriting were rewritten and forwarded accordingly. For this series of packet process, we used the Data Plane Development Kit (DPDK), a tool that could speed up packet processing. The framework was applied to the anonymization process, and the delay due to the anonymization process was 0.195 ms. With this framework, it is possible to achieve the packet content rewriting process at any point between the IoT device and the cloud by modifying the location of the edge node.

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Evaluation of Communication Overhead for Distributed Deep Learning for Local Data Privacy

Okuda Y., Nishikawa A., Nishi H.

IECON Proceedings (Industrial Electronics Conference)    1 - 6 2023年

ISSN  21624704

　概要を見る

In recent years, there has been growing interest in using big data for machine learning applications. However, as data are often distributed across multiple clients, privacy and physical limitations can make it difficult to aggregate and use these data on centralized servers. Federated learning and split neural networks enable machine learning models to be built without requiring the aggregation of distributed data. These methods have received increased attention in the industrial sector as a means of eliminating impediments to privacy preservation in data sharing across various institutions, such as smart factories. One critical aspect of implementing such methods in practice is analyzing the time variation of traffic and estimating the throughput required for operationalizing machine learning. Previous studies have formulated traffic characteristics without considering packet overhead and measured only the total traffic and the throughput per iteration; such an approach is inadequate from a traffic monitoring perspective. To address these issues, this study conducted an empirical investigation of traffic patterns under realistic conditions, with a particular focus on quantifying traffic and latency. The results of this study suggest that due to the dynamic nature of throughput, it is essential to measure traffic using time units that can accommodate the temporal variability of traffic.

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Estimation of Indoor Space Temperature Distribution Using Heat Maps

Hayashi E., Sonoda A., Nishikawa A., Nishi H.

IECON Proceedings (Industrial Electronics Conference)    1 - 6 2023年

ISSN  21624704

　概要を見る

In recent years, there has been an increasing demand for accurate measurement of the spatial dispersion of air temperature in air conditioning control for indoor environments. This spatial dispersion of temperature is caused by the unevenness of air conditioning equipment, local temperature gradients due to human activities, and local heat exchange with outdoor air, all of which hinder the provision of a comfortable environment. This issue requires resolution in various fields, including the agricultural sector, where it can negatively impact crop growth. To address this issue, it is necessary to measure air temperature at multiple points, although the number of sensors that can be installed is typically limited, and the temperature at a single point is typically used as a representation of the temperature in the space. Additionally, heat maps using infrared array sensors can acquire temperature distribution in a narrow area; however, they cannot directly determine air temperature as they only measure the surface temperature of an object. Therefore, we propose a deep learning-based method that utilizes both heat maps acquired from infrared array sensors and air temperature data obtained from environmental sensors to estimate air temperature. We evaluate its effectiveness by varying the experimental environment, the model structure, and the resolution and number of heat maps added as input. Furthermore, we assess the usefulness of utilizing a Graphics Processing Unit (GPU), which is a cost-effective solution that can be installed on low-resolution sensors and edge devices. The outcomes indicate that the proposed model can attain an estimation accuracy of under 1 mean squared error (MSE) in approximately 200 seconds, while also exhibiting practical feasibility for deployment on edge devices, including residential abodes and agricultural premises.

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Distributed MQTT Brokers Infrastructure with Network Transparent Hardware Broker

Toyohara T., Nishi H.

Proceedings - 2023 11th International Symposium on Computing and Networking, CANDAR 2023    182 - 188 2023年

　概要を見る

In recent years, the number of IoT devices has been rapidly increasing. Therefore, MQ Telemetry Transport (MQTT) has attracted attention as a lightweight protocol for IoT devices. MQTT employs a publish/subscribe model of communication via a broker, and since the performance of the MQTT broker directly affects the quality of service, various studies have been conducted to improve its performance. Among them, the hardware implementation of MQTT broker has higher performance than software implementations in terms of publish throughput and processing delay. However, there are some problems such as inflexibility and resource limitations. Therefore, we propose a distributed MQTT brokers infrastructure using the hardware broker. In this architecture, the software broker on the cloud and the hardware broker at the edge region work in cooperation to achieve low latency processing at the edge region and software flexibility. The hardware broker operates network transparently, so that end devices communicate with the software broker in the cloud and do not need to be aware of the presence of the hardware broker at the edge region. This enables resource and processing load distribution without affecting end devices. We implemented the network transparent hardware broker in a field-programmable gate array (FPGA) and evaluated it.

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Differential Privacy Framework using Secure Computing on Untrusted Servers

Jia J., Nishi H.

Proceedings - 2023 IEEE 6th International Conference on Industrial Cyber-Physical Systems, ICPS 2023 （IEEE）     1 - 6 2023年

ISSN  2769-3902

　概要を見る

Smart cities use cutting-edge technologies to monitor the real world and improve various aspects of human life, such as traffic, agriculture, electric power grid, and medical care. However, protecting users' privacy is crucial in smart-city applications for service coordination. Any leakage of users' sensitive information may prevent users from sharing their data, and thereby hinder the progress of smart cities. Differential privacy (DP) is one of the approaches that protects sensitive information in a dataset, and strongly resists background knowledge attacks. This study proposes a central differential privacy scheme using secure computing methods. After receiving the ciphertext of the data, the central data curator in this system generates a perturbed dataset in the encrypted domain. The unmodified data of each user is not exposed to the data curator, therefore the data users do not need a trusted data curator. Moreover, compared with the existing models in which significant amount of noise is locally added before sending the data to the data curator, the proposed scheme adds considerably less noise while maintaining the same privacy requirement, resulting in enhanced data utility. Model evaluation demonstrates that our system effectively protects the privacy of individuals and provides accurate data for statistical analysis.

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Black Soldier Fly Bioconversion System: A Digital Twin Approach

Yu G., Nishi H., Pang C., Gu Q., Lin Y., Liang J., Dai W., Vyatkin V.

IEEE International Symposium on Industrial Electronics 2023-June   1 - 4 2023年

　概要を見る

Insect-based bioconversion is an emerging and economically viable approach that could simultaneously solve the global issues on food waste treatment and protein shortage. An essence of insect-based bioconversion is to feed insects on food wastes and then harvest and refine the developed insects into value-added commodities. This is a circular bioeconomic approach that can efficiently upcycle the nutrients and energy in food waste streams back into agricultural supply chains, but the difficulty is how to realize mass production of insects. This paper reports a commercial-scale insect-based bioconversion system using black soldier flies, whose design and development follow a digital twin paradigm. In particular, an industrialized rearing environment has been established, where the larvae growth can be systematically monitored, controlled, and managed to evaluate the overall bioconversion process efficacy. The system has been deployed in a pilot plant, whose Phase I is capable of handling 20 tons of food waste feedstocks per day and has been consecutively operating to date.

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Attention-PVS for Domestic Hot Water Consumption Forecasting in Individual Household

Sonoda A., Compagnon P., Reyboz M., Nishi H.

IECON Proceedings (Industrial Electronics Conference)    1 - 6 2023年

ISSN  21624704

　概要を見る

Short-term hot water consumption forecasting in an individual household is important to realize energy-efficient hot water management while meeting users' comfort. However, consumption traits in an individual household contain much irregularity, and that gives additional challenges to accurate forecasting. This paper proposes an Attention-PVS model to tackle this issue, which focuses on consumption values with similar past consumption trends. In this study, verification experiments were conducted on a real-household hot water consumption dataset collected by Electricity of France. The model was evaluated with its consumption forecasting error with MAE, MSE, and RMSE metrics and computational costs. As for the computational cost, experiments were conducted on NVIDIA Jetson Nano (Jetson) to validate the applicability to embedded systems. The results revealed that the proposed model performs consumption forecasting with comparable accuracy to other state-of-the-art models. Additionally, while LSTM scored lower error than the proposed model, Attention-PVS performed training and inference on Jetson in shorter times than LSTM.

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Temperature Monitoring and Airflow Control System for Balancing the Greenhouse Environment Using IEEE 1451 Standards

Nishi H., Takayama Y., Wijekoon J.L., Song E.Y., Lee K.B.

IECON Proceedings (Industrial Electronics Conference)    1 - 6 2023年

ISSN  21624704

　概要を見る

It is vital to establish a suitable thermal environment for greenhouses to improve production quality for crop cultivation. However, in greenhouse environments, uneven temperature, caused by the influence of outside temperature, leads to unevenness in air conditioning and results in sub-optimized crop quality and yield. This paper introduces a real-time temperature monitoring and airflow controlling system using IEEE P1451.0 and P1451.1.6 standards to balance and improve greenhouse environments. The controlling system consists of three components: an infrared array of smart temperature sensors (STS) placed inside and outside the greenhouse, a smart airflow controller (SAC), and a temperature monitoring and airflow control application (TMACA). The network communications among STS, TMACA, and SAC are based on IEEE P1451.0 and P1451.1.6 standard network services using the message queuing telemetry transport (MQTT) protocol. In the system, the TMACA can monitor the temperatures inside and outside the greenhouse using two STS, process and estimate the temperature differences inside the greenhouse, and then control and equalize the temperature of the greenhouse using the SAC based on the temperature differences to balance and improve the greenhouse environment.

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動きベクトル検出用 3D 画像フィルタの FPGA への実装

陳宇晨， ウェイカイジ， 西宏章， 天野英晴

電子情報通信学会技術研究報告; 信学技報 122 (174), 13-14 2022年

スマートコミュニティ・スマートシティでのエッジコンピューティングの本当の役割 エッジコンピューティングの位置自在性・透明性が社会を変える

西 宏章

JBPress - 2022年

• CiNii Research

Hierarchical Multiobjective Distributed Deep Learning for Residential Short-Term Electric Load Forecasting

Sakuma Y., Nishi H.

IEEE Access （IEEE Access）  10   69950 - 69962 2022年

ISSN  2169-3536

　概要を見る

Short-term load forecasting plays an essential role in appliance control in households and demand response at the neighborhood or community level. When load forecasting is simultaneously performed at different levels in a smart community, a central method that directly aggregates raw household data may incur a security issue. However, an individual method that builds separate models for each level requires additional data collection. We propose a distributed load forecasting framework that is secure, data efficient, and resource efficient. Our proposed method shares the latent variables, the reduced expression of the input data, of the household models without revealing the raw data. The latent variables are aggregated and fed to the neighborhood model, and during inference, input data collection can be abbreviated in the neighborhood. Because household models provide informative latent variables, the number of model parameters for the neighborhood model can be reduced. Our proposed method is evaluated using real electricity consumption data for six different models under 24 h and 1 h ahead forecasting. Our proposed method with the long short-term memory, multi-layer perceptron, and convolution neural network-based models presents the degradation in average mean absolute percentage error 3.68% and 5.16% at most for household and neighborhood forecasting, respectively, compared to the individual method. At the same time, it reduces the neighborhood's model size by approximately 53%.

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Survey of Protocols for V2G Communications

Shom S., Guha A., Tsang K.F., Nishi H., Wu C.K., Shuaib K., Sharif H., Alahmad M.

Proceedings of the IEEE International Conference on Industrial Technology （IEEE）  2022-August   1 - 8 2022年

　概要を見る

The bi-directionality of electric vehicle (EV) charging has proved to be important for load leveling purposes, amongst others. Thus, Vehicle-to-Grid (V2G) communication protocols are a necessity which ensures that the information exchange that takes place during this process, is efficient, secure, and reliable. Several research articles regarding different V2G communication protocols have been published over the years. This paper summarizes current relevant research in this area in order to provide a reference guide for researchers interested in this subject.

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Personal Data Access and Distribution Management Extension to FIWARE

Namba Y., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IEEE）  2022-October   1 - 6 2022年

ISSN  21624704

　概要を見る

In smart communities which refers to communities that leverage the use of technologies to benefit their citizens, it is necessary to ensure data interoperability among services and secure data operations. Particularly, it is necessary to manage the data path of services based on edge computing to consider the level of privacy between regions and at different network layers. FIWARE, a smart city operating system(OS) that has been recently deployed in several cities, provides an application programming interface (API) based on common rules to ensure interoperability and to enable coordination and distribution of services and data. However, the data distribution control component is assumed to be placed in the cloud, and it does not have a distribution management mechanism. In this study, within the architecture of FIWARE, we have built a mechanism that manages data paths on an edge by using tags of dataflows which is associated with the personal information in the packets. Additionally, we implemented a benchmark and measured a processing delay for gathering personal information. In the simulation environment, the processing time delay was 0.05 seconds by using proposed system when the control component is placed in the egde area.

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Optimum Configuration of Edge Computing Protocols for Industrial Internet-of-Thing Applications

Bakhtiari M., Wei Y., Nishi H., Fung Tsang K., Aljuhaishi N., Alahmad M.

IECON Proceedings (Industrial Electronics Conference) （IEEE）  2022-October   1 - 6 2022年

ISSN  21624704

　概要を見る

Industrial Internet-of-Things (IIoT) technology has been rigorously developed in recent years, moving towards the ambitious goal of industry 4.0, Network Automation. However, there are a few critical challenges regarding the implementation of a reliable IIoT ecosystem for different applications; security, battery life, and bandwidth are controversial challenges. All the challenges regarding IIoT are mainly struggling within the edge computing smaller box of the big picture in which a cloud is an upstream object while sensors and actuators act as downstream devices. Therefore, having a reliable IIoT ecosystem necessitates focusing on the whole IIoT's challenges in the edge computing smaller box; first realizing the vital, practical demands of a specific IIoT application, and then defining the compatible protocols to form the effective edge computing configuration. This paper reviews four IIoT case study applications with their specific requirements and their counterpart sensor/actuator properties to find the appropriate edge computing protocols satisfying their demands.

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Implementation of IEEE P1451.0 and P1451.1.6 Sensor Networks

Nishi H., Lee K.B.

IECON Proceedings (Industrial Electronics Conference) （IEEE）  2022-October   1 - 6 2022年

ISSN  21624704

　概要を見る

This paper introduces an implementation of a standard-based sensor network for the Internet of Things (IoT) applications adhering to the Institute of Electrical and Electronics Engineers (IEEE) P1451.0 and P1451.1.6 draft standards. The architecture of standards-based sensor networks consists of P1451.0 and P1451.1.6-based wide-area networks (WAN), P1451.0, and P1451.5.X-based wireless local area networks (WLANs), and P1451.0 and P1451.2-based wired local-area networks (LANs). A few case studies P1451.0 and P1451.1.6 WAN are provided with preliminary results to verify some network service specifications of the sensor network based on P1451.0 network services and P1451.1.6 MQTT interfaces in order to verify and improve draft specifications helping to achieve interoperability.

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Greenhouse Heat Map Generation with Deep Neural Network Using Limited Number of Temperature Sensors

Sonoda A., Takayama Y., Sugawara A., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IEEE）  2022-October   1 - 6 2022年

ISSN  21624704

　概要を見る

In recent years, there have been many attempts in smart agriculture to increase efficiency and profitability, especially in horticultural agriculture, where profitability is high. One of the measures to achieve this goal is to realize uniform quality by equalizing temperatures in greenhouses which have a huge influence on a process of growth. The most common method for measuring temperatures in greenhouses is the use of temperature sensors. However, to measure continuous temperature distribution by scattering temperature sensors, a large number of temperature sensors must be installed, a method that should be avoided because of its high cost. Therefore, the goal of this paper is to estimate the temperature of substances such as crops and soil in greenhouses, which are secondarily affected by the atmospheric temperature, at a low cost instead of measuring atmospheric temperatures in a costly way. Temperature sensors for substances must be directly attached to the target object to measure its surface temperature, which can lead to the deterioration in quality. In contrast, infrared array sensors can measure the surface temperature of materials from a distance. They have been increasingly used in recent years due to growing demand, and they can be used to measure the surface temperature of a wide range of objects in a greenhouse. However, infrared array sensors also have many operational problems, such as dirty lenses, and the measurement error is larger than that of temperature sensors. Therefore, this paper proposes a machine learning model that predicts continuous temperature distribution in the form of a 16 ×18 pixels heat map from a limited number of temperature sensors. Evaluation results show that our approach is useful in different greenhouse environments, including different airconditioning systems. In addition, the model is computationally inexpensive enough to run in practical fields with limited computational resources; therefore, it can be run on relatively inexpensive embedded terminals. As for the accuracy, the average error of the heat map obtained by the proposed model is as small as 0.28 [°C/pixel].

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Effective Information Selection Method on Spatiotemporal Information Infrastructure with Photogrammetry

Sugawara A., Sonoda A., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IEEE）  2022-October   1 - 6 2022年

ISSN  21624704

　概要を見る

In recent years, there has been an increase in the demand for three-dimensional data of geospatial information in various fields, such as automatic driving and disaster prevention. Beyond5G (above 5th generation network), which features wideband, low latency, reliable connection, allows for the easily collection of spatial information of many points and times from camera-equipped vehicles, such as self-driving cars and drones. Spatiotemporal information at any location and at any time can be provided depending on users' requests. However, there are instances where the target point's spatiotemporal information and the request's target time have not been collected. Therefore, appropriate data completion is required to provide this service seamlessly. To create 3D models using photogrammetry, images are required; therefore, multiple videos that captured the streets near our university were prepared and split into frames. Then, those images were stored in our local storage. The information of the recording date, weather, file path to the image, and location (latitude and longitude) were saved to our database per frame. When users request spatiotemporal information, this system commences searching for images that meet the requirements. When the number of matched images are sufficient, the 3D model is created. When it is insufficient, the data are complemented appropriately.

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Anomalous Sound Detection, Extraction, and Localization for Refrigerator Units Using a Microphone Array

Nishikawa A., Hattori K., Tanaka M., Muranami H., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IEEE）  2022-October   1 - 6 2022年

ISSN  21624704

　概要を見る

Anomaly detection is one of the key applications of data utilization in smart factories, particularly in monitoring factory facilities. Early detection and resolution of anomalies, such as system failures, can lead to cost reduction and quality stabilization. One of the targets of abnormality detection applications in the industry section is a refrigerator unit used in food processing factories and warehouses. Anomalies in the early stages in refrigerator units appear in the operating sounds, which can enable their detection. In this study, we propose a method for detecting abnormal sound, extracting abnormal frequency components, and identifying the direction of the abnormal sound source. To identify the direction of the anomalous sound source, multi-channel sound recorded by a microphone array is used. To the best of our knowledge, no method has yet been proposed for anomaly sound detection using multi-channel acoustic data. In the proposed method, anomaly scores calculated in each channel of the microphone array are aggregated to determine whether the entire data is anomalous or not. Anomalous sounds were extracted from the anomaly data using a deep generative model. The extracted anomalous sounds were used to localize the sound source and the direction of the anomalous source was identified. The proposed method improved the precision of anomaly sound detection while maintaining the recall rate of a conservative comparison method. Using the proposed method, anomalous sounds were extracted from the anomaly data, and their arrival directions were identified.

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An Implementation of a 3D Image Filter for Motion Vector Generation on an FPGA Board

Chen Y., Wei K., Nishi H., Amano H.

Proceedings - 2022 10th International Symposium on Computing and Networking, CANDAR 2022 （IEEE）     83 - 89 2022年

ISSN  2379-1888

　概要を見る

Object detection and tracking technology are essential in many ways with the increasing demand for remote video conferencing and video surveillance. This paper focuses on a method that combines an object detection method based on a CNN (Convolutional Neural Network) with a motion-vector-based object tracking method in specified frames instead of the whole frame stream. Although this method can improve the throughput with a small memory requirement, it requires 3D image filters to reduce the noise in each motion vector. The immense computing power needed for 3D image filters prevents this method from being popularly used. To address this problem, we propose to implement the technique on an FPGA and offload the filters and CNN engine on the FPGA hardwired logic. We implemented slide window-based image filters on a Zynq Ultrascale+ FPGA board and achieved 23.42 times performance improvement for the median filter and 55.46 times for the average filter, respectively. Considering the resource usage, it appeared that we could implement these 3D image filters design with YOLO on the target FPGA.

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Consistency Guaranteed Multi Container Migration for Smart Community Network Services

Abeysiriwardhana W. A. Shanaka P., Morishima Ryo, Miura Tatsuki, Nishi Hiroaki

IEEJ Transactions on Electronics, Information and Systems （The Institute of Electrical Engineers of Japan）  141 （ 12 ） 1453 - 1461 2021年12月

ISSN  0385-4221

　概要を見る

Smart Community (SC) uses IoT sensors to provide smart grid control, traffic management, and similar IoT services. These services expect to run at the network edge or fog layer to provide low latency network services, encapsulate citizens’ private information, support low-cost IoT terminals from cyber-attacks, and support other cutting-edge fog and edge services. SC edge is a service platform that supports edge/fog services for IoT terminals by using Docker containers. Initially, SC edge/fog computing nodes did not support the function of service migration. However, service migration is necessary to support remote deployment and service distribution in SC networks. The existing container migration techniques focus mainly on resource utilization. However, SC services should handle loss-free data stream processing and order-preservation of network packets to gather IoT sensor data after migration. In addition, SC services require one-to-many migration to support high throughput loads when required. Therefore, this paper focuses on enhancing SC service flexibility by introducing migration for relocatable and network consistency guaranteed containerized services. SC edge proposes multiple container migration techniques that are suitable for network services. The proposed techniques can improve resource consumption, guarantee network traffic consistency, and apply one-to-many migration patterns. Layer leveraging migration (LLM) reduces the overall migration time by 10.8% for an elastic search Docker container than available Docker migration methods. Additionally, consistency guaranteed migration (CGM) is proposed to guarantee network consistency. However, CGM consumes additional resources compared to LLM for IoT data management. Finally, One to N Consistency Guaranteed Migration (O2NCGM) is proposed to support one-to-many migration with data consistency that shows similar performance to CGM.

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Consistency Guaranteed Multi Container Migration for Smart Community Network Services

Abeysiriwardhana W. A. Shanaka P., Morishima Ryo, Miura Tatsuki, Nishi Hiroaki

電気学会論文誌Ｃ（電子・情報・システム部門誌） （一般社団法人 電気学会）  141 （ 12 ） 1453 - 1461 2021年12月

ISSN  03854221

　概要を見る

<p>Smart Community (SC) uses IoT sensors to provide smart grid control, traffic management, and similar IoT services. These services expect to run at the network edge or fog layer to provide low latency network services, encapsulate citizens’ private information, support low-cost IoT terminals from cyber-attacks, and support other cutting-edge fog and edge services. SC edge is a service platform that supports edge/fog services for IoT terminals by using Docker containers. Initially, SC edge/fog computing nodes did not support the function of service migration. However, service migration is necessary to support remote deployment and service distribution in SC networks. The existing container migration techniques focus mainly on resource utilization. However, SC services should handle loss-free data stream processing and order-preservation of network packets to gather IoT sensor data after migration. In addition, SC services require one-to-many migration to support high throughput loads when required. Therefore, this paper focuses on enhancing SC service flexibility by introducing migration for relocatable and network consistency guaranteed containerized services. SC edge proposes multiple container migration techniques that are suitable for network services. The proposed techniques can improve resource consumption, guarantee network traffic consistency, and apply one-to-many migration patterns. Layer leveraging migration (LLM) reduces the overall migration time by 10.8% for an elastic search Docker container than available Docker migration methods. Additionally, consistency guaranteed migration (CGM) is proposed to guarantee network consistency. However, CGM consumes additional resources compared to LLM for IoT data management. Finally, One to N Consistency Guaranteed Migration (O2NCGM) is proposed to support one-to-many migration with data consistency that shows similar performance to CGM.</p>

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• CiNii Research

Air-Conditioning Control with Spatial Recognition Using Stereo Infrared Array Sensors

Takayama Y., Saito S., Sakuma Y., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IECON Proceedings (Industrial Electronics Conference)）  2021-October 2021年10月

ISSN  9781665435543

　概要を見る

Depending on the location of the air conditioner and the shape of a room, air-conditioning control may be inefficient resulting in temperature imbalance. When attempting to solve this problem, it is vital to understand the spatial structure of a room (including its size and shape) and the location of air conditioners and then automatically control the airflow and direction according to the structure. However, such a method for recognizing spatial structures has not yet been established. In this paper, we propose a spatial recognition method using stereo infrared array sensors (SIRA sensors) installed in an air conditioner. Our system detects objects in the obtained thermal images and estimates their distances using triangulation. In addition, the room's size and shape are estimated based on the assumption that the room size lies within the detection range. The distances to the front and left/right walls were estimated in one-meter-wide classes. The estimation accuracy was compared using two types of IRA sensors: thermopile array sensors and thermal diode infrared sensors. Regarding the distance estimation of persons from the captured stereo thermal images, the average error rate was 12.5% for both types. The distance to each wall was estimated within a 1 m error range for the thermal diode infrared sensor. Moreover, applications of the proposed spatial recognition to air-conditioning control were demonstrated. Specifically, we propose a method to control the airflow direction and volume by considering the room's geometry. An L-shaped room was modeled and simulated. From the results, the spatial recognition reduced the unevenness in temperature by adjusting the airflow based on the room shape. These results indicate that the proposed method can be practically used for spatial recognition to efficiently improve user comfort by controlling air-conditioning based on the spatial structure and eliminating uneven temperature.

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Time Synchronization of IEEE P1451.0 and P1451.1.6 Standard-based Sensor Networks

Nishi H., Song E.Y., Nakamura Y., Lee K.B., Liu Y., Tsang K.F.

IECON Proceedings (Industrial Electronics Conference) （IECON Proceedings (Industrial Electronics Conference)）  2021-October 2021年10月

ISSN  9781665435543

　概要を見る

This paper introduces the time synchronization approaches to the Institute of Electrical and Electronics Engineers (IEEE) P1451.0 standard-based sensor networks for Internet of Things (IoT) applications. A time synchronization architecture of IEEE P1451.0 standard-based sensor networks is described including two-level time synchronization systems in IEEE P1451.0 and P1451.1.X standards-based wide-area network (WAN) and IEEE P1451.0 and P1451.5.X standards-based local area networks (LANs). However, this paper mainly focuses on the time synchronization approach of IEEE P1451.0 and P1451.1.6 standards-based WANs and provides two implementations of time synchronization of IEEE P1451.0 and P1451.1.6 using wireline and wireless networks with their preliminary results to verify that the time synchronization approach of IEEE P1451.1.6 functions properly. In addition, the time synchronization transducer electronic data sheets (TEDS) of P1451.1.6 is described.

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Recommendation System for Energy Consumption Behavior Change on Residents' Response and Stress

Takayama Y., Sakuma Y., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IECON Proceedings (Industrial Electronics Conference)）  2021-October 2021年10月

ISSN  9781665435543

　概要を見る

Home energy management system (HEMS), enabled by the development of the Internet of Things (IoT), issue behavior change recommendations to encourage residents to reduce their energy consumption. Receiving these suggestions from HEMS makes it easier for them to set specific reduction goals and raise their awareness of energy saving. This feedback will lead to effective power reduction in the household sector. However, each user has unique preferences, and uniformly generated recommendations may not be followed if they do not match the preferences of the specific user. In addition, frequent recommendations that are not aligned with their preferences may stress users and decrease their motivation to reduce energy consumption. This paper presents a practical method of making behavior change recommendations reflecting users' response rates and considering their stress. Targeting the action of opening a window, we illustrate how our system induces behavioral change. To increase the users' response rate and reduce their stress, we adjust the recommendation for each user from two perspectives. First, assuming that users open windows mainly depending on the external temperature, humidity, wind, and weather, we introduce the k-nearest neighbors (k-NN) classification using these parameters as the explanatory variables to predict the possibility that the user accepts the window-opening recommendation. Generating recommendations only when the predicted probability is high enables building a unique recommendation system considering user preferences. Second, if the recommendations are sent frequently, users may become tired of following them; this leads to a situation in which users ignore recommendations or turn off their notifications. To avoid such a situation, we propose adjusting the delivery interval according to the users' response rate. When we schedule the notification cycle, we introduce a forgetting curve, assuming that the users' stress on the recommendation decreases over time. We conducted a simulation using historical weather data. The response rate and thermal sensation of users with different variations were set, and the delivery timing of the recommendation was changed according to these factors. The proposed methods are expected to effectively generate behavioral changes by having users take medium-to long-term initiatives without lowering their motivation.

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Dataflow Management Platform for Smart Communities using an Edge Computing Environment

Shimahara S., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IECON Proceedings (Industrial Electronics Conference)）  2021-October 2021年10月

ISSN  9781665435543

　概要を見る

As various data services are provided to realize Society 5.0, the usage of personal data is estimated to increase along with the explosive increase in data traffic. It is important that the protection of privacy keeps pace with increases in the exchange of data containing personal information. Starting from the enforcement of the General Data Protection Regulation (GDPR), stricter privacy protection regulations are expanding to more countries. These restrictions require that personal data should be hidden or anonymized before they are propagated over the network. The secondary usage of data is assumed in smart communities, and systems that can protect privacy are required for secure network infrastructures. In this study, we propose an edge-based computing platform that manages the privacy of users on the network of a smart community. For the platform, we prepared three models: The Basic, Preceding Packet, and Piggyback models. These are considered OpenFlow models, and the network efficiency for each was evaluated.

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Efficient GAN-Based Unsupervised Anomaly Sound Detection for Refrigeration Units

Hatanaka S., Nishi H.

IEEE International Symposium on Industrial Electronics （IEEE International Symposium on Industrial Electronics）  2021-June 2021年06月

ISSN  9781728190235

　概要を見る

A smart factory or Industry 4.0 is creating an epoch for manufacturing and its production lines. It reduces the total cost by monitoring and predicting the expected faults of factory lines and products. One of the essential challenges is to develop a technology to detect and predict abnormalities at an early stage without human resources. For this reason, the automation of anomaly detection is now attracting attention. Many statistical and machine-learning methods have been studied for anomaly detection. In this study, we focus on a refrigeration system for large storage, where the failures of the system will cause enormous losses. Moreover, this type of system was independently designed according to the environment, location, and storage items. Under this condition, it is difficult to train discriminative models for anomaly detection using training data that include failure data. In addition, it is indispensable to provide a basis for determining whether the system is abnormal to achieve future treatments. Therefore, deep generative models are used to achieve unsupervised abnormality detection. Because the sensing system's cost for detecting system failures should be reduced, the proposed system uses low-cost microphone arrays to monitor sounds and source locations. The system also provides a rationale by visualizing and mentioning irregular sounds. Furthermore, this study compared various deep generative models in terms of accuracy and showed that the Efficient GAN-based method achieved the highest accuracy.

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Household Nutrition Analysis and Food Recommendation U sing Purchase History

Honda M., Nishi H.

IEEE International Symposium on Industrial Electronics （IEEE International Symposium on Industrial Electronics）  2021-June 2021年06月

ISSN  9781728190235

　概要を見る

To prevent non-communicable diseases, it is important to review consumers' dietary habits. Most existing applications for improving eating habits require users to upload photos of their meals and record them manually, but such procedures are time-consuming and laborious. Because the targets of the proposed method are those who are not highly conscious of their health, it is necessary to make the application easy to use. This study applies the history of supermarket purchases to calculate nutrient intake and recommend foods that improve nutritional balance with the least amount of user input. Consequently, the nutrient intake can be estimated with an acceptable error, and foods that are easy for the user to purchase can be recommended. Because the proposed method does not use artificial intelligence technologies to generate recommendations, the reasons for food recommendations are clear and the computational cost is reduced.

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Thermal energy storage performance of tetrabutylammonium acrylate hydrate as phase change materials

Kiyokawa H., Tokutomi H., Ishida S., Nishi H., Ohmura R.

Applied Sciences (Switzerland) （Applied Sciences (Switzerland)）  11 （ 11 ）  2021年06月

ISSN  2076-3417

　概要を見る

Kinetic characteristics of thermal energy storage (TES) using tetrabutylammonium acrylate (TBAAc) hydrate were experimentally evaluated for practical use as PCMs. Mechanical agitation or ultrasonic vibration was added to detach the hydrate adhesion on the heat exchanger, which could be a thermal resistance. The effect of the external forces also was evaluated by changing their rotation rate and frequency. When the agitation rate was 600 rpm, the system achieved TES density of 140 MJ/m3 in 2.9 hours. This value is comparable to the ideal performance of ice TES when its solid phase fraction is 45%. UA/V (U: thermal transfer coefficient, A: surface area of the heat ex-change coil, V: volume of the TES medium) is known as an index of the ease of heat transfer in a heat exchanger. UA/V obtained in this study was comparable to that of other common heat exchang-ers, which means the equivalent performance would be available by setting the similar UA/V. In this study, we succeeded in obtaining practical data for heat storage by TBAAc hydrate. The data obtained in this study will be a great help for the practical application of hydrate heat storage in the future.

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Load balancing method using server temperature prediction considering multiple internal heat sources in data centers

Yao X., Omori M., Nishi H.

2021 IEEE International Conference on Mechatronics, ICM 2021 （2021 IEEE International Conference on Mechatronics, ICM 2021）  2021年03月

ISSN  9781728144429

　概要を見る

The increasing demand for cloud computing services to more flexibly use computing resources has led to a severe problem of excessive energy consumption in data centers. In recent research, the energy consumption of computing and cooling equipment has attracted much attention. To reduce the energy consumption in data centers, the energy efficiency of the cooling equipment needs to be considered. This study theoretically modeled the relations between the server's internal heat sources and exhaust temperatures. First, we proposed a model that expands the previous study to describe the temperature change delay and to apply it to multiple internal heat sources. Then, we experimentally evaluated the prediction accuracy of the proposed model using a real server and conducted a simulation to confirm the efficiency of this prediction model for load balancing. The simulation results showed that the proposed method reduced the average maximum server temperature by 0.27 °C compared to the conventional method, which theoretically leads to energy savings of 260 kW per day and 95 MW per year in typical data centers.

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Adaptive control method of HVAC for uniformizing comfort at Japanese residential living rooms using deep reinforcement learning

Sakuma Y., Nishi H.

IEEJ Transactions on Electronics, Information and Systems （IEEJ Transactions on Electronics, Information and Systems）  141 （ 3 ） 373 - 382 2021年03月

ISSN  03854221

　概要を見る

There is a great demand for high-quality indoor thermal environments while achieving comfort and saving the energy for heating, ventilation, and air conditioning (HVAC) devices offer a tradeoff. The room shapes, partitioning, and the location of diffusers cause uneven comfort and degrade thermal satisfaction. Therefore, an HVAC control method that provides uniform thermal comfort while saving energy is required. In such cases, providing uniform comfort in a room can be a low-cost and energy-efficient solution. We propose a deep reinforcement learning (DRL)-based HVAC control method to uniformize comfort in a room. The proposed method considers the use of sensors, which are already deployed in existing HVAC devices and is adaptive to rooms with different conditions. The proposed method controls the HVAC device based on the prediction of the room's thermal response using wall heatmaps of the target room. The heatmaps are obtained by using a simple measuring system of an infrared thermopile array sensor. For evaluating the proposed method's adaptivity to rooms with different conditions, a computer flud dynamics (CFD)-based simulation was designed. The coldest period throughout a year was chosen as the evaluation period; uniformizing comfort is the most difficult when the temperature difference between outside and inside a room and the validity of the proposed method for the other periods is implied. The usefulness of the proposed method for the chosen period was shown for the selected period; the proposed method achieved an improvement of 33.9% in thermal comfort performance while on average increasing energy consumption by 6.3%, against that of comparable approaches. Moreover, the comfort performance during learning is confirmed to be similar to those of the existing method.

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Purchasing behavior prediction model for real stores considering product cluster and time-series patterns

Sakuma Y., Yoshida M., Nishi H.

IEEJ Transactions on Electronics, Information and Systems （IEEJ Transactions on Electronics, Information and Systems）  141 （ 3 ） 471 - 482 2021年03月

ISSN  03854221

　概要を見る

Recently, cashless payment services have been rapidly introduced, increasing the demand for recommender systems for real stores. Recommender systems have been well-studied and successful in many Internet services. While factors such as the diversity and coverage of products should be considered, the prediction accuracy of user purchasing behaviors is the most crucial factor in a recommender system. This research proposes a purchasing behavior prediction model for real stores by using purchase history data collected from a supermarket in Saitama City, Japan, as a part of a smart city project. Time-series patterns in purchasing behavior indicate the sales characteristics of supermarkets, where daily products are predominately purchased. For example, some users repeatedly purchase specific products in a certain period or purchase different products from their previous visit. Many previous studies have only considered the compatibility between the features of users and items; however, this work also models the time-series patterns of purchasing behavior. The proposed prediction model adopts ensemble learning, in which weak learners learn the two factors (the compatibility between users and items) and time-series patterns of purchasing behavior separately. Moreover, product names in supermarkets often contain meta-information of the product alongside the item name. For instance, the product name “three tomatoes from Gunma Prefecture” includes information about the quantity and manufacturer as well as the item name “tomato”. However, products that are the same item but have different product names are likely to be purchased together in the context of purchasing activity, thus deteriorating the prediction accuracy. Therefore, a product classification method is proposed to categorize the products for each item. The experimental results show 3.2% and 10.6% improvements in the precision-recall area under the curve (PR-AUC) for the proposed method compared to models that consider only the compatibility between users and items and the time-series patterns of purchasing behavior, respectively.

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特集 スマートシステムと計測・制御技術: 超スマート社会に向けて

Y Sakuma, H Nishi

電気学会論文誌 C (電子・情報・システム部門誌) 141 (3), 373-382 2021年

Digital Watermarking for Anonymized Data with Low Information Loss

Nakamura Y., Nishi H.

IEEE Access （IEEE Access）  9   130570 - 130585 2021年

ISSN  2169-3536

　概要を見る

At present, massive amounts of data are utilized for artificial intelligence technologies such as machine learning and deep learning. However, these data must be utilized carefully while preserving data privacy. Data anonymization is a technique enabling both data mining and privacy protection, preventing the identification of individuals by generalizing the data to include multiple records with the same values. In this study, we consider a data-publishing infrastructure for personal data sharing. The infrastructure anonymizes data prior to publishing it to users for privacy protection; however, the problem of unauthorized republishing by malicious users must be considered. To address this issue, we studied digital watermarking methods that correlate data users with anonymized data. Our previous method embedded information indicating the original user to detect illegally republished data. However, this method did not focus on information loss. This study proposes another digital watermarking method for anonymized data that achieves low information loss. The proposed method replaces values in tuples to embed information. To reduce the information loss caused by the embedding, the proposed method selects replacement values from the candidates whose meanings are similar to the original. We propose the use of vector-conversion tables to select replacement values. The proposed method also extends the maximum length of the embedded bit string by embedding multiple bits into a single tuple. Moreover, we measured the tolerance to distortion attacks to evaluate the efficacy of the proposed method. The proposed method is non-blind, i.e., data prior to digital watermarking is required to perform extraction.

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Hardware Implementation of MQTT Broker and Precise Time Synchronization Using IoT Devices

Yamamoto K., Fukuhara A., Nishi H.

IEEJ Transactions on Electrical and Electronic Engineering （IEEJ Transactions on Electrical and Electronic Engineering）  17 （ 2 ） 209 - 217 2021年

ISSN  19314973

　概要を見る

In recent years, while internet of things (IoT) devices and cloud computing environments have been penetrated, the increase in communication latency and concentration of traffic caused by data centers has deteriorated the quality of some network services. Message Queuing Telemetry Transport (MQTT) is a well-known protocol for exchanging messages between dedicated applications. MQTT employs a publish–subscribe model in which a broker mediates communication between IoT devices and applications. To improve service quality, the processing latency of the broker should be reduced. Moreover, the broker's throughput must be increased. IoT devices, in particular, must maintain a highly accurate time to provide some IoT services. This study proposed hardware implementation of MQTT broker and evaluated the accuracy of an MQTT-based time synchronization method. The proposed MQTT architecture's hardware resource utilization is also provided. We confirmed that our implementation achieved high throughput, low latency, and low jitter MQTT broker, which satisfies the smart city services for automated drive and power control, which must be less than a few milliseconds. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

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Trajectory Anonymization through Laplace Noise Addition in Latent Space

Sakuma Y., Tran T.P., Iwai T., Nishikawa A., Nishi H.

Proceedings - 2021 9th International Symposium on Computing and Networking, CANDAR 2021 （Proceedings - 2021 9th International Symposium on Computing and Networking, CANDAR 2021）     65 - 73 2021年

ISSN  2379-1888

　概要を見る

In recent years, the volume of captured location-based movement data has drastically increased with the prevalence of smartphones. Mobility data are commonly used for smart assistant and personalized advertising applications. However, such data contain considerable sensitive information; thus, they must be anonymized before they can be published or analyzed. In this study, we investigate the problem of anonymization for trajectory publication. Anonymizing trajectories is challenging because they have high dimensionality in both the spatial and temporal domains. Traditional anonymization methods cannot handle high dimensionality without significantly sacrificing data utility. The proposed method addresses this limitation by training a Seq2Seq autoencoder model to reconstruct trajectories from the spatiotemporal input, followed by distributing the Laplace noise to the principal components of the Seq2Seq encoder's hidden-layer output under differential privacy. By distributing the privacy budget in the latent space, the proposed method can output trajectories that satisfy differential privacy while maintaining embedded information. Experimental results from the application of the proposed method to real-life movement trajectory data from Saitama, Japan, demonstrate a reduction in data loss by up to 75.7 % while maintaining significant data utility.

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Standards and Interoperability in Industrial Electronics - A Trending View

Huang V., Nishi H., Espírito-Santo A., Chen A., Bruckner D.

IEEE International Conference on Industrial Informatics (INDIN) （IEEE International Conference on Industrial Informatics (INDIN)）  2021-July   1 - 6 2021年

ISSN  19354576

　概要を見る

With the active development of IES in standards since the mid-2010s, the society has made considerable progress with multiple standards' developments. This paper presents the results of engaging in standards' development within and across borders of an IEEE society. In particular, the hands-on INTEROP Plugfests, coupled with the CoEs, provide platforms to create ideas for standards, develop standards, initiate interoperability among multiple vendors, providing competitive time-to-market advantage for involved industry partners.

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Network Transparent Decrypting of Cryptographic Stream Considering Service Provision at the Edge

Hiraga H., Nishi H.

IEEE International Conference on Industrial Informatics (INDIN) （IEEE International Conference on Industrial Informatics (INDIN)）  2021-July   1 - 6 2021年

ISSN  19354576

　概要を見る

The spread of Internet of Things (IoT) devices and high-speed communications, such as 5G, makes their services rich and diverse. Therefore, it is desirable to perform functions of rich services transparently and use edge computing environments flexibly at intermediate locations on the Internet, from the perspective of a network system. When this type of edge computing environment is achieved, IoT nodes as end devices of the Internet can fully utilize edge computing systems and cloud systems without any change, such as switching destination IP addresses between them, along with protocol maintenance for the switching. However, when the data transfer in the communication is encrypted, a decryption method is necessary at the edge, to realize these transparent edge services. In this study, a transparent common key-exchanging method with cloud service has been proposed as the destination node of a communication pair, to transparently decrypt a secure sockets layer-encrypted communication stream at the edge area. This enables end devices to be free from any changes and updates to communicate with the destination node.

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Consistency Guaranteed Multi Container Migration for Smart Community Network Services

S WA, R Morishima, T Miura, H Nishi

IEEJ Transactions on Electronics, Information and Systems 141 (12), 1453-1461 2021年

Consistency Guaranteed Multi Container Migration for Smart Community Network Services

Abeysiriwardhana W.A.P.S., Morishima R., Miura T., Nishi H.

IEEJ Transactions on Electronics, Information and Systems （IEEJ Transactions on Electronics, Information and Systems）  141 （ 12 ） 1453 - 1461 2021年

ISSN  03854221

　概要を見る

Smart Community (SC) uses IoT sensors to provide smart grid control, traffic management, and similar IoT services. These services expect to run at the network edge or fog layer to provide low latency network services, encapsulate citizens' private information, support low-cost IoT terminals from cyber-attacks, and support other cutting-edge fog and edge services. SC edge is a service platform that supports edge/fog services for IoT terminals by using Docker containers. Initially, SC edge/fog computing nodes did not support the function of service migration. However, service migration is necessary to support remote deployment and service distribution in SC networks. The existing container migration techniques focus mainly on resource utilization. However, SC services should handle loss-free data stream processing and order-preservation of network packets to gather IoT sensor data after migration. In addition, SC services require one-to-many migration to support high throughput loads when required. Therefore, this paper focuses on enhancing SC service flexibility by introducing migration for relocatable and network consistency guaranteed containerized services. SC edge proposes multiple container migration techniques that are suitable for network services. The proposed techniques can improve resource consumption, guarantee network traffic consistency, and apply one-to-many migration patterns. Layer leveraging migration (LLM) reduces the overall migration time by 10.8% for an elastic search Docker container than available Docker migration methods. Additionally, consistency guaranteed migration (CGM) is proposed to guarantee network consistency. However, CGM consumes additional resources compared to LLM for IoT data management. Finally, One to N Consistency Guaranteed Migration (O2NCGM) is proposed to support one-to-many migration with data consistency that shows similar performance to CGM.

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Consistency Guaranteed Multi Container Migration for Smart Community Network Services

W. A.P.Shanaka Abeysiriwardhana, Ryo Morishima, Tatsuki Miura, Hiroaki Nishi

IEEJ Transactions on Electronics, Information and Systems 141 （ 12 ） 1453 - 1461 2021年

ISSN  0385-4221

　概要を見る

Smart Community (SC) uses IoT sensors to provide smart grid control, traffic management, and similar IoT services. These services expect to run at the network edge or fog layer to provide low latency network services, encapsulate citizens' private information, support low-cost IoT terminals from cyber-attacks, and support other cutting-edge fog and edge services. SC edge is a service platform that supports edge/fog services for IoT terminals by using Docker containers. Initially, SC edge/fog computing nodes did not support the function of service migration. However, service migration is necessary to support remote deployment and service distribution in SC networks. The existing container migration techniques focus mainly on resource utilization. However, SC services should handle loss-free data stream processing and order-preservation of network packets to gather IoT sensor data after migration. In addition, SC services require one-to-many migration to support high throughput loads when required. Therefore, this paper focuses on enhancing SC service flexibility by introducing migration for relocatable and network consistency guaranteed containerized services. SC edge proposes multiple container migration techniques that are suitable for network services. The proposed techniques can improve resource consumption, guarantee network traffic consistency, and apply one-to-many migration patterns. Layer leveraging migration (LLM) reduces the overall migration time by 10.8% for an elastic search Docker container than available Docker migration methods. Additionally, consistency guaranteed migration (CGM) is proposed to guarantee network consistency. However, CGM consumes additional resources compared to LLM for IoT data management. Finally, One to N Consistency Guaranteed Migration (O2NCGM) is proposed to support one-to-many migration with data consistency that shows similar performance to CGM.

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ICSIM 2021: 2021 The 4th International Conference on Software Engineering and Information Management, Yokohama Japan, January 16-18, 2021

ICSIM （ACM）  2021年

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Standards and Interoperability in Industrial Electronics–A Trending View

V Huang, H Nishi, A Espírito-Santo, A Chen, D Bruckner

2021 IEEE 19th International Conference on Industrial Informatics (INDIN), 1-6 2021年

Preface

Nishi, H.

ACM International Conference Proceeding Series    VII - VIII 2021年

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RPC: An approach for reducing compulsory misses in packet processing cache

Yamaki H., Nishi H., Miwa S., Honda H.

IEICE Transactions on Information and Systems （IEICE Transactions on Information and Systems）  E103D （ 12 ） 2590 - 2599 2020年12月

ISSN  09168532

　概要を見る

We propose a technique to reduce compulsory misses of packet processing cache (PPC), which largely affects both throughput and energy of core routers. Rather than prefetching data, our technique called response prediction cache (RPC) speculatively stores predicted data in PPC without additional access to the low-throughput and power-consuming memory (i.e., TCAM). RPC predicts the data related to a response flow at the arrival of the corresponding request flow, based on the request-response model of internet communications. Our experimental results with 11 real-network traces show that RPC can reduce the PPC miss rate by 13.4% in upstream and 47.6% in downstream on average when we suppose three-layer PPC. Moreover, we extend RPC to adaptive RPC (A-RPC) that selects the use of RPC in each direction within a core router for further improvement in PPC misses. Finally, we show that A-RPC can achieve 1.38x table-lookup throughput with 74% energy consumption per packet, when compared to conventional PPC.

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FPGA Context-based Live Migration Maintaining Network Consistency

Fukuhara A., Shohata S., Nishi H.

Proceedings - 2020 8th International Symposium on Computing and Networking Workshops, CANDARW 2020 （Proceedings - 2020 8th International Symposium on Computing and Networking Workshops, CANDARW 2020）     81 - 86 2020年11月

ISSN  9781728199191

　概要を見る

Based on the development of networking services and the emergence of various computing environments, such as edge and cloud environments, appropriate service allocation based on processing delays, computational resources, data volumes, and other requirements has become crucial. To support dynamic load shifting and reduce service downtime, service allocation should be performed using live migration, which maintains network consistency. There have been many studies on live migration techniques and their implementation in software applications. However, limited research has been reported on field-programmable gate array (FPGA)-based transparent service migration. This paper proposes and evaluates a transparent live-migration architecture for an FPGA computing system that maintains network consistency before and after migration and enables effective migration without any software or hardware extensions on communicating edges or cloud nodes. The proposed architecture achieves sufficient throughput and sufficiently low downtime to be introduced into cloud and edge nodes.

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Application Protocol Conversion Corresponding to Various IoT Protocols

Saito K., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IECON Proceedings (Industrial Electronics Conference)）  2020-October   5219 - 5225 2020年10月

ISSN  9781728154145

　概要を見る

In Internet of Things (IoT) networks, devices use various application protocols, such as MQ telemetry transport (MQTT), constrained application protocol (CoAP), and extensible messaging and presence protocol (XMPP). However, because of the various protocols used, devices adopting different protocols cannot communicate mutually; thus, service interoperability issues arise. To enhance service interoperability, protocol conversion is required. Because different protocols are used in IoT networks, they are required to correspond to various protocols and have high extensibility for protocol conversion. In this paper, a protocol conversion method that satisfies these requirements is proposed. The proposed method converts packets into a middle format before converting them into target protocols. Conversion rules are described for each protocol; thus, the proposed method has high extensibility. We confirmed that clients that use the proposed conversion method could successfully connect to other devices using different protocols and communicate mutually through servers. The protocols included MQTT, CoAP, XMPP, and SMTP. Furthermore, the throughput degradation caused by the conversion process is small.

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Energy Optimization Technologies in Smart Homes

Moayedi S., Almaghrebi A., Haase J., Nishi H., Zucker G., Aljuhaishi N., Alahmad M.

IECON Proceedings (Industrial Electronics Conference) （IECON Proceedings (Industrial Electronics Conference)）  2020-October   1974 - 1979 2020年10月

ISSN  9781728154145

　概要を見る

Energy optimization in the built environment is receiving more attention in the last decade. This leads to remarkable technological advancements in energy monitoring, data communication, energy storage, control, and data analysis applications. Energy monitoring can be aggregate (Non-Intrusive load monitoring -NILM) or disaggregate (Intrusive load monitoring -ILM) based on the location in which the monitoring takes place. Sensors communicate via wired or wireless means, and several protocols are developed to support communications in smart homes. This real-time data can be sent to remote controllers for further analysis, training and prediction applications using Internet of Things (IoT) that provides a cost-effective solution for energy management systems. This manuscript presents an overview of current innovation in smart homes for the advancement of building technology.

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Smart community edge: Stream processing edge computing node for smart community services

Abeysiriwardhana W.A.S.P., Wijekoon J.L., Nishi H.

IEEJ Transactions on Electronics, Information and Systems （IEEJ Transactions on Electronics, Information and Systems）  140 （ 9 ） 1030 - 1039 2020年09月

ISSN  03854221

　概要を見る

A smart community utilizes information technology to interconnect and manage community infrastructures. Smart community networks should support a large number of Internet of Things (IoT) devices in community infrastructures to provide services such as smart grids and health monitoring systems. In comparison to cloud-based solutions, smart community services can be deployed in the edge computing area to reduce service latency and to encapsulate private and local information. Furthermore, smart community services can leverage network virtualization technologies to support IoT network services at the edge. A service-oriented container-based solution that processes data streams from IoT sensors using conventional hardware will improve the compatibility and latency of these virtualized network services at the edge. To this end, a software-based edge computing node, namely, the smart community edge (SCE), was proposed to develop a platform for smart community services. SCE supports data-tapping applications, especially for IoT devices, and has a stream processing feature with a comparatively shorter processing delay. This tapping and processing function was named multi-service authorized stream content analysis. SCE captures network stream data and enables service applications using shared memory buffers for a shorter processing delay. SCE supports services as Docker containers to provide remote deployment, service compatibility, and service isolation. SCE allows IoT services to run at the edge through conventional hardware devices, thus, reducing the service latency for delay-sensitive services, which approximately require to sustain latency less than 10 ms. The proposed SCE achieves 10 Gbps bandwidth with a 16 core server when compared to the f-stack library with a 5 Gbps bandwidth. SCE deployment on conventional hardware devices shows its capability of operating at 1-10 Gbps line rates to support up to eight services at 500 Mbps data bandwidth per service, while keeping the overall latency below 1 ms. Therefore, SCE provides a platform for delay-sensitive IoT services at the network edge.

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Anomaly Detection Based on Histogram Methodology and Factor Analysis Using LightGBM for Cooling Systems

Yanabe T., Nishi H., Hashimoto M.

IEEE Symposium on Emerging Technologies and Factory Automation, ETFA （IEEE Symposium on Emerging Technologies and Factory Automation, ETFA）  2020-September   952 - 958 2020年09月

ISSN  9781728189567

　概要を見る

The development of the Internet of Things (IoT) has created an environment in which numerous sensors and actuators are connected to the Internet. Machines and management systems in factories use data from such sensors and actuators to improve their work efficiency, and are essential parts of today's smart factories. The vision of a smart factory is based on the concept of Industry 4.0 (I4.0), a subset of the fourth industrial revolution, in which smart factories support the operator and maintenance processes of the factory from an I4.0 perspective. The analysis of big data gathered by IoT devices in factories, particularly for the use of anomaly detection, can aid in achieving product quality stabilization. For example, if a large refrigerator in a warehouse breaks down, the quality of stock food will deteriorate, and food loss may become significant. In the case of anomaly detection, machine status monitoring and accident prediction are required to reduce the operation and maintenance costs. Furthermore, the introduction cost of such systems can be reduced by generalizing them (the systems). However, the data types as well as the sensor and actuator types, differ between factories. Therefore, nonparametric statistical methods are required for anomaly detection. By contrast, factor analysis requires a costless method, one that does not require an overhaul of machinery. Consequently, it is necessary to adopt a machine learning-based method using sampled data. In this study, we proposed a method of anomaly detection and factor analysis for cooling systems in smart factories using appropriate methodologies for detection and analysis. The proposed method consists of two phases: anomaly detection and factor analysis. In the anomaly detection stage, Gaussian kernel density estimation was used to calculate the occurrence distribution. Two types of anomaly scores, cumulative density value and KL divergence, were defined. The probability distribution was estimated with a constant window frame to reflect a tendency to increase. In the factor analysis stage, target values were predicted using LightGBM. The factor of abnormalities was detected by comparing the results of two predictions: one using all the features, and the other using the data, which excluded a factor to detect the contribution of the factor.

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Representation of Plant Structure using XML and Its Application to Cultivation Management

Saito S., Yuyama K., Ishii M., Huang V., Nishi H.

IEEE Symposium on Emerging Technologies and Factory Automation, ETFA （IEEE Symposium on Emerging Technologies and Factory Automation, ETFA）  2020-September   125 - 131 2020年09月

ISSN  9781728189567

　概要を見る

The agricultural population in Japan is aging and shrinking. Therefore, it is necessary to improve the efficiency of farm work. Additionally, it takes many years to learn the skills required for farming, which discourages many young people from joining the field. As a countermeasure to this problem, smart agriculture technology is gaining increasing attention. Smart agriculture is an approach to increasing the quantity and quality of crops by leveraging advanced technologies. In smart agriculture, a large amount of data are collected from various sensors and internet of things devices. As the use of information and communication technology in agriculture spreads, the demand for data sharing between different agricultural systems increases accordingly. However, electronic data exchange interfaces for agricultural data are not standardized. Therefore, in Japan, it has been recommended to unify data formats using extensible markup language (XML). In this study, we focused on data regarding crop growth states and developed a method for representing plant structure using XML. In the proposed method, branches and fruits are extracted from plant images and their connections are expressed using the hierarchical structure of XML. Compared to conventional management of crop growth states based on images, the proposed method significantly reduces data size. Furthermore, because XML elements can be easily searched and sorted using XPath and XQuery, the XML format makes data easy to utilize for many services. For example, by counting numbers of fruits, profits and work times can be predicted. Additionally, data regarding plant structure is useful for directing farmers or robots to harvest fruits. The proposed method contributes to improving productivity and helps inexperienced farmers.

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Video Object Detection Method Using Single-Frame Detection and Motion Vector Tracking

Nohara M., Nishi H.

IEEE International Conference on Industrial Informatics (INDIN) （IEEE International Conference on Industrial Informatics (INDIN)）  2020-July   119 - 125 2020年07月

ISSN  9781728149646

　概要を見る

Video traffic on the Internet has been increasing rapidly and accounts for a large percentage of the total traffic. To process the increasing number of videos, edge computing is preferable for load balancing and bandwidth reduction. However, edge areas have less computational resources than cloud areas, and high-performance GPUs for processing videos at high speed are not always present. Therefore, a memory-saving and high-Throughput video analysis method is necessary for analyzing videos in edge areas. In this paper, a video object detection method using single-frame detection and motion vector tracking is proposed. This method is classified as a pixel and compressed domain analysis method and is realized by compensating motion using the motion vectors that already exist in the compressed domain. This method is divided into two processes: CNN-based object detection and motion vector-based object detection. In addition, a network-Transparent platform for video reconstruction in edge areas is constructed. The network-Transparent service can be installed without modifying the existing end-device network settings, network configuration, and routing. The platform enables video object detection services to be added on without modification of these settings.

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Low-Information-Loss Anonymization of Trajectory Data Considering Map Information

Hashimoto M., Morishima R., Nishi H.

IEEE International Symposium on Industrial Electronics （IEEE International Symposium on Industrial Electronics）  2020-June   499 - 504 2020年06月

ISSN  9781728156354

　概要を見る

Preserving an individual's privacy when publishing data are essential, and anonymization has been getting attention as the solution. When anonymizing data, it is necessary to contemplate the possibilities of linkage with other data which can lead to privacy violation. Trajectory data are one of the data, which contains personal data. Consequently, various anonymization methods of trajectory data have been considered by researchers. However, most research handle trajectory data as polylines connecting location data or as a sequence of location data. In other words, it lacks on considering the connection with map data. In this paper, we will consider the anonymization of trajectory data of moving users matched according to map data, which we will be calling pathing data. According to k-anonymity principle, data can be published if there are k of the same data. We will use k-anonymity principle to quantitively judge the risk of privacy violation and propose two methods that can fulfill the anonymization requirements with low data loss. The two methods are Map Matching to Node (MMtoN) and Map matching to Edge (MMtoE), which judges k-anonymity by segments of pathing data.

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Airflow Direction Control of Air Conditioners Using Deep Reinforcement Learning

Sakuma Y., Nishi H.

Proceedings of 2020 SICE International Symposium on Control Systems, SICE ISCS 2020 （Proceedings of 2020 SICE International Symposium on Control Systems, SICE ISCS 2020）     61 - 68 2020年03月

ISSN  9784907764647

　概要を見る

Achieving a uniform comfort within an indoor housing environment is important for health and productivity while saving the energy consumption of a Heating, Ventilation, and Air Conditioners (HVAC) device. The optimal control of an HVAC system is a well-studied area. While many works explore the optimal temperature set-point, a few works consider effective airflow direction control. This work proposes an airflow direction control method that aims uniform comfort of the indoor environment using a deep reinforcement learning (DRL) approach. We implemented our proposed DRL framework using computational fluid dynamics (CFD) simulation software. Our proposed method was evaluated for comfort and energy consumption. The experimental results show the improvements for our proposed method in comfort by 21.3 % while reducing energy consumption by 34.5 % for the average than the baseline method.

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Precision variable anonymization method supporting transprecision computing

Harada K., Charles H.P., Nishi H.

International Conference on Advanced Communication Technology, ICACT （International Conference on Advanced Communication Technology, ICACT）  2020   35 - 42 2020年02月

ISSN  9791188428045

　概要を見る

Recently, the number of Internet of Things (IoT) sensors has been increasing rapidly; hence, various data are gathered. As a secondary use of the data, they are useful in providing new services, such as the demand response service in the Smart Grid. However, data services cause several problems in preserving privacy and during computation. This study focuses on these two significant problems. First, the invasion of privacy while using the data to provide such new services is problematic. A lot of private information is available in the data. For example, power consumption data may reveal the lifestyle of the residents, and the technique of obtaining information is known as nonintrusive load monitoring. Second, the penetration of IoT devices and sensors increases the computational and communicating energy consumption for processing the data and for providing various services using the data. In this paper, a new method is proposed to solve these two problems. This method is based on the fact that the anonymization process reduces the amount of information itself, as well as the quantity of computational resources required. This leads to a trade-off between anonymization level and computational cost. For example, raw data have a maximum amount of information and maximum computational cost. In contrast, fully generalized data (all zero data) have minimum amount of information and minimum computational cost. Compared to the conventional method, the proposed method demonstrated lower precision and a higher error rate. Therefore, the proposed method aims to control the trade-off and enables the provision of anonymized data with less information, the required anonymity level, and low computational cost compared to the conventional method. The proposed method is practiced using power consumption data gathered from the Urban Design Center Misiono (UDCMi) and the demand response service is evaluated as an experiment using the data. In this evaluation, a simple model of energy consumption was used in the calculation, which uses the required bit width of the arithmetic logic unit (ALU) for providing the service. The computational efficiency of the proposed method was increased by 60% when k = 2 and by 65% when k = 3, 4, 5, 6 compared to the conventional method. The method can also maintain an acceptable range of service error. The transprecision platform can restrict energy consumption by reducing the bit width of the data. Therefore, the proposed anonymization method can also reduce energy consumption by achieving lower usage of the ALU based on the transprecision architecture.

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IoT-based monitoring for smart community

Nishi, H., Nakamura, Y.

Urban Systems Design: Creating Sustainable Smart Cities in the Internet of Things Era    335 - 344 2020年

　概要を見る

Data integration of different infrastructure is fundamental to smart communities. In this chapter, case studies of data-oriented smart community projects, such as energy reduction and efficient-use services, recommendation services, mobility services, and health services, are described.

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Industrial Edge Computing: Enabling Embedded Intelligence

Dai W., Nishi H., Vyatkin V., Huang V., Shi Y., Guan X.

IEEE Industrial Electronics Magazine （IEEE Industrial Electronics Magazine）  13 （ 4 ） 48 - 56 2019年12月

ISSN  19324529

　概要を見る

The term industrial edge computing is used to describe a distributed platform that integrates communication, computation, and storage resources for performing real-time applications that can be directly accessed from the cloud. A step toward the industrial Internet revolution, industrial edge computing is designed to facilitate agile connectivity, real-time control, and data optimization, while enabling intelligent applications, ensuring tight security, and protecting privacy. Industrial edge computing makes use of what is known as edge computing nodes (ECNs), which bridge the gap between the physical world and the digital world by acting as smart gateways for assets, services, and systems. The IEEE P2805 Standards are being developed for defining protocols for self-management, data acquisition, and machine learning through cloud-edge collaboration on ECNs.

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Face image anonymization as an application of multidimensional data K-anonymizer

Nakamura T., Sakuma Y., Nishi H.

Proceedings - 2019 7th International Symposium on Computing and Networking Workshops, CANDARW 2019 （Proceedings - 2019 7th International Symposium on Computing and Networking Workshops, CANDARW 2019）     155 - 161 2019年11月

ISSN  9781728152684

　概要を見る

Recently, the development of data communication networks and advances in computer processing capacity have significantly increased the amount of data to be managed. Although future innovations using data are expected, privacy violation of data has become a problem. For example, image disclosure in Social Networking Service may result in infringement of portrait rights. Previously, studies on anonymization have been conducted to disclose data for protecting personal information. However, conventional anonymization, even for high-dimensional data such as faced images, uses an averaging operation in anonymization and does not consider complex relationships between dimensions. Therefore, the loss of semantic meaning increases because it is caused by the anonymization process, assuming an Euclidean data space. We herein propose Multidimensional Inputs K-anonymizing Unit(MIKU), an anonymization algorithm focusing on face image anonymization as a typical example of high-dimensional datMIKU enables anonymization that retains the image quality. As the comparison method directly anonymizes images, the quality of images is deteriorated. MIKU considers the relation between dimensions using the latent space of StyleGAN. The effect of using latent space was confirmed by comparing the quantitative results of Fréchet Inception Distance(FID) and the qualitative evaluation of the output image with the comparison method. The quantitative results by FID proved that MIKU achieved better performance when K-anonymity was large. When K-anonymity is small, we clarified that the image quality of the comparison method such as FID could not be measured correctly and was overestimated because of the effect of the inception model's linearity. In addition, the qualitative evaluation of anonymized images shows that MIKU generates a more natural image in the contour and hair expressions than the comparison method, and the anonymized images of MIKU contain no unnatural edge lines on a face such as those generated in the comparison method.

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Exploring Variability in IoT Data for Human Activity Recognition

Sakuma Y., Kleisarchaki S., Gurgen L., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IECON Proceedings (Industrial Electronics Conference)）  2019-October   5312 - 5318 2019年10月

ISSN  9781728148786

　概要を見る

Human Activity Recognition (HAR) is a well-studied scientific area that has gained much traction with the rise of Internet of Things (IoT). Despite the interest in HAR for a wide spectrum of domains (technological, medical, etc.) only a few works exist, which study the variability in IoT data. To correctly perceive this variability, it is essential to dynamically model the evolving context of daily-life activities. Additionally, it is required to reduce the calculation cost of HAR, which is crucial for security and real-time applications. For the purpose of dynamically modeling, three context-aware approaches are formalized along with a context-free baseline. This study demonstrates improvements in terms of both of accuracy and calculation cost by considering variability in IoT data; our experimental study on real datasets reduced calculation cost by 20% while increasing accuracy by 20%.

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Practical Estimation Method of Thermal Sensation Using an Infrared Array Sensor

Saito S., Nishi H.

IECON Proceedings (Industrial Electronics Conference) （IECON Proceedings (Industrial Electronics Conference)）  2019-October   497 - 502 2019年10月

ISSN  9781728148786

　概要を見る

In heating, ventilation, and air conditioning control, it is crucial to maintain the comfort of residents. Thermal comfort is typically assessed using the predicted mean vote (PMV) index. PMV depends on six factors: air temperature, mean radiant temperature, air velocity, air humidity, metabolic rate, and clothing insulation. Although PMV can be estimated by measuring these factors directly, this process is costly because multiple sensors are required. Furthermore, measuring metabolic rate and clothing insulation is especially costly because expensive and complex sensors are required. To solve these problems, this paper proposes a practical method for estimating PMV by estimating metabolic rate and clothing insulation using a low-cost infrared array (IrA) sensor. In this study, an IrA sensor called 'Grid-EYE' is adopted. PMV parameters other than air velocity and humidity can be measured when the proposed method and an IrA sensor are implemented in an air conditioner. Human detection is done using the temperature map captured by the sensor and their PMV values are estimated individually. Heat sources around people are also detected and their influence on PMV estimation is evaluated. Practical experiments demonstrate the validity of the proposed method by providing estimated PMV values close to theoretical values and real sensations. Therefore, the proposed method can contribute to providing comfortable living spaces and improving energy consumption and amenities efficiently.

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Implementation of content-based anonymization edge router on netfpga

Fukuhara A., Iwai T., Sakuma Y., Nishi H.

Proceedings - 2019 IEEE 13th International Symposium on Embedded Multicore/Many-Core Systems-on-Chip, MCSoC 2019 （Proceedings - 2019 IEEE 13th International Symposium on Embedded Multicore/Many-Core Systems-on-Chip, MCSoC 2019）     123 - 128 2019年10月

ISSN  9781728148823

　概要を見る

In recent years, a large number of Internet of Things (IoT) devices have appeared. Accordingly, various services using data from such devices have been proposed. However, the collected raw data include private information, and thus, privacy problems arise. Data anonymization is a method for removing privacy-sensitive information from raw data. Data anonymization for IoT data services should satisfy the following requirements. First, the raw data should be anonymized between a device and the cloud server. Second, the anonymization methods and the destinations of the collected data should be flexibly configured, as they depend on data types and agreements with data suppliers. Third, network transparency is necessary for ease of installation. However, conventional data anonymization systems do not satisfy these requirements. We propose anonymization hardware that functions as a network router on network edges. It directly anonymizes data in network packets. Moreover, it decides the destination IP address of the packets and anonymizes data based on their content. For high-Throughput and low-power processing of the packets, the proposed hardware was implemented by using a field-programmable gate array. The throughput of the proposed hardware achieved 10 Gbps wire speed, and the power consumption was lower than that of software implementation.

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Dynamic load balancing using actual workload traces based on central processing unit temperatures

Nakajo Y., Athavale J., Yoda M., Joshi Y., Nishi H.

Journal of Electronic Packaging, Transactions of the ASME （Journal of Electronic Packaging, Transactions of the ASME）  141 （ 3 ）  2019年09月

ISSN  10437398

　概要を見る

With the rapid growth in demand for distributed computing, data centers are a critical physical component of the "cloud."Recent studies show that the energy consumption of data centers for both cooling and computing keeps increasing, and the growth in server power densities makes it ever more challenging to keep the servers below their maximum operating temperature. This paper presents a new dynamic load-balancing approach based on individual server central processing unit (CPU) temperatures. In this approach, a load balancer assigns a task in real time to a server based on the objective to keep the CPU temperatures below a maximum value. Experimental studies are conducted in a single rack based on production workload traces of Google clusters. This study also compares the performance of this method with two other load balancing approaches, Round Robin, and a CPU utilization-based method in terms of temperature distributions, local fan rotation speeds, system loads, and server processing times. Furthermore, we investigate how the effect of the proposed load balancing changes with different assumed applications run on servers. The results indicate that this new method can more effectively reduce both server CPU temperatures and local fan rotation speed in a rack especially for the most of web applications.

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Estimation of building thermal performance using simple sensors and air conditioners

Sakuma Y., Nishi H.

Energies （Energies）  12 （ 15 ）  2019年07月

ISSN  1996-1073

　概要を見る

Energy and environmental problems have attracted attention worldwide. Energy consumption in residential sectors accounts for a large percentage of total consumption. Several retrofit schemes, which insulate building envelopes to increase energy efficiency, have been adapted to address residential energy problems. However, these schemes often fail to balance the installment cost with savings from the retrofits. To maximize the benefit, selecting houses with low thermal performance by a cost-effective method is inevitable. Therefore, an accurate, low-cost, and undemanding housing assessment method is required. This paper proposes a thermal performance assessment method for residential housing. The proposed method enables assessments under the existing conditions of residential housings and only requires a simple and affordable monitoring system of power meters for an air conditioner (AC), simple sensors (three thermometers at most), a BLE beacon, and smartphone application. The proposed method is evaluated thoroughly by using both simulation and experimental data. Analysis of estimation errors is also conducted. Our method shows that the accuracy achieved with the proposed three-room model is 9.8% (relative error) for the simulation data. Assessments on the experimental data also show that our proposed method achieved Ua value estimations using a low-cost system, satisfying the requirements of housing assessments for retrofits.

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Energy-efficient task distribution using neural network temperature prediction in a data center

Omori M., Nakajo Y., Yoda M., Joshi Y., Nishi H.

IEEE International Conference on Industrial Informatics (INDIN) （IEEE International Conference on Industrial Informatics (INDIN)）  2019-July   1429 - 1434 2019年07月

ISSN  9781728129273

　概要を見る

The growing demand for computing resources leads to a serious problem of excessive energy consumption in data centers. In recent studies, energy consumption of both computing and cooling equipment is drawing attention. For improving the energy efficiency of cooling equipment such as computer room air conditioners (CRACs), it is neccesary to predict temperatures in data centers and to optimize thermal management in data centers. In this study, we propose a temperature prediction method for servers in a data center using a neural network. We used the prediction result for distributing task targeting temperature-based load balancing. First, we conducted an experiment in a real data center to evaluate the prediction accuracy of the proposed method. We then simulated task distribution based on the predicted temperatures and compared the maximum CPU temperature with a non-predictive approach. The results indicated that the proposed method can reduce future CPU temperatures successfully compared to the non-predictive approach, though in exchange for high computational cost.

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Network transparent fog-based IoT platform for industrial IoT

Morishima R., Nishi H.

IEEE International Conference on Industrial Informatics (INDIN) （IEEE International Conference on Industrial Informatics (INDIN)）  2019-July   920 - 925 2019年07月

ISSN  9781728129273

　概要を見る

There has been rapid growth in the number of Internet of Things (IoT) devices that produce a large volume of data such as location data, temperature data, and power usage data. These data are used in various types of services on IoT platforms. IoT services such as autonomous vehicles and factory automation system have the following three requirements. First, confidential data such as machine ID, power usage, and location information need to be locally anonymized before they are sent to a cloud server. Second, these applications require low latency response of less than 10 ms. Third, the bandwidth usage that an enormous number of IoT devices generate needs to be efficiently reduced to alleviate the burden on the cloud server. However, existing IoT platforms have limitations on the configuration of applications because most of them are cloud-based. In this study, we propose a fog-based IoT platform, where fog nodes achieve network transparency for the IoT devices and the cloud server. The network-transparent machine can be installed without modification of the existing network configuration and routing. Fog nodes transparently achieve the three requirements: anonymization of specific data in packets, real-time feedback, and reduction in the bandwidth usage.

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Optimized service function path selection for iot devices using virtual network function performance data

Abeysiriwardhana W., Wijekoon J., Nishi H.

International Conference on Information Networking （International Conference on Information Networking）  2019-January   165 - 170 2019年05月

ISSN  9781538683507

　概要を見る

Software defined networking (SDN) and network function virtualization (NFV) are proposed as software based applications to cater to smart services requirements of smart communities. The services are linked together to support different sets of clients using service function chaining (SFC). Service functions (SFs) in an SFC must be distributed among available computing resources by creating a service function path (SFP) allowing resource management and optimal SF execution. This paper proposes a novel SFP allocation algorithm considering the computation capabilities of hardware resources while minimizing the completion time of SFCs. The proposed algorithm shows 10% performance increment compared to recently developed algorithms such as nearly optimal service function path and optimal service function selection algorithms.

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Error correction method considering fog and edge computing environment

Matsui K., Nishi H.

Proceedings - 2019 IEEE International Conference on Industrial Cyber Physical Systems, ICPS 2019 （Proceedings - 2019 IEEE International Conference on Industrial Cyber Physical Systems, ICPS 2019）     517 - 521 2019年05月

ISSN  9781538685006

　概要を見る

This study aims to execute error correction service of sensor data at fog and edge, which are the computing environments for distributing the concentrated processes in a cloud by using hierarchical computing resources. Service integrity of error correction was evaluated as an essential application of fog and edge computing environment, which can use the locality of fog and edge. Errors or outliers in data may cause a serious problem in system controlling and visualization application for behavior change when by using the malformed data or visualization of the data. The proposed methods can solve the data congestion problems at a cloud in the future IoT era.

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Feature extraction and resident number prediction method using power consumption data

Yoshida M., Imanishi T., Nishi H.

IEEJ Transactions on Electronics, Information and Systems （IEEJ Transactions on Electronics, Information and Systems）  139 （ 3 ） 227 - 236 2019年

ISSN  03854221

　概要を見る

A large amount of power consumption information generated from private houses is being aggregated nowadays, particularly by the spread of smart electric meters. Applications that utilize these data are widely studied, and several services have been proposed. In order to utilize the power demand information effectively, an appropriate feature extraction and selection method is necessary. In this paper, a feature extraction method for power consumption information is proposed. Extracted features are used to predict the “number of household members (number of residents)” using typical machine learning algorithms, namely, Support Vector Machine (SVM), k-Nearest Neighborhood (k-NN), and Random Forest (RF). The number of residents represents significant information for the marketing departments of several industries such as real estate and construction industries. The proposed feature extraction method consists of two steps: feature variable generation and feature variable selection. In the feature variable generation step, we have used both fundamental statics and an ARMA model to generate 33 feature variables. In the feature variable selection step, the extracted feature variables are first ranked by applying Analysis of Variance (ANOVA). An appropriate feature variable set is selected by assessing several combinations of the 33 features, based on proposed extended algorithm of Recursive Feature Elimination (RFE). Our overall feature extraction method is evaluated based on the prediction accuracy using extracted feature variables. Compared with the accuracy using feature variables extracted by conventional methods, the accuracy is improved by 6.78%, 4.98%, and 8.11% for k-NN, SVM, and RF, respectively, and we have successfully proven validity of our proposition.

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Software-accelerated Service-oriented Router for Edge and Fog Service Enhancement Using Advanced Stream Content Analysis

Shanaka W.A., Abeysiriwardhana P., Wijekoon J., Tennekoon R.L., Nishi H.

IEEJ Transactions on Electronics, Information and Systems （IEEJ Transactions on Electronics, Information and Systems）  139 （ 8 ） 891 - 899 2019年

ISSN  03854221

　概要を見る

Fog services have been gaining momentum due to the demand generated by IoT-based services that require data and services to be provided at the edge of the network. This phenomenon creates several problems for Internet systems, such as security, and data management. Particularly, edge and fog computing addresses these problems and provides new services by solving these issues. To this end, a service-oriented router (SoR) was proposed and extended to provide edge and fog services by performing authorized stream content analysis (ASCA). Packet Capture (Libpcap) library was used to develop the initial implementation of the SoR to perform ASCA using conventional hardware and software platforms. However, Libpcap implementation together with conventional hardware demonstrated limited performance. Consequently, this paper proposes a method using Intel technologies such as the Intel Data Plane Development Kit and Hyperscan to accelerate stream processing and string matching on SoRs. The paper compares both implementations of SoRs and evaluates the performance with regard to packet throughput, CPU utilization, and memory usage. Furthermore, the latency of major functions is evaluated under Libpcap-based and DPDK-based SoR implementations. The results demonstrate an increase of more than 0.8 Gbps in bandwidth in a 1 Gbps link using less hardware utilization when SoR is implemented using Intel technologies compared to the original Libpcap implementation.

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Image analysis on the flexural behaviors of RC beams with artificial damage and the effects of repair

Kota Matsue, Takashi Matsumoto, Ko Kakuma, Hiroaki Nishi

INTERNATIONAL CONFERENCE ON SUSTAINABLE CIVIL ENGINEERING STRUCTURES AND CONSTRUCTION MATERIALS (SCESCM 2018) （E D P SCIENCES）  258 2019年

ISSN  2261-236X

　概要を見る

In cold and snowy regions, frost damage happened in an RC bridge deck slab leads to horizontally layered cracks, which results in the disintegration of cover concrete. Since this deterioration mode occurs inside an RC slab, it is usually difficult to detect them. It is possible that the slab performances have already decreased when the deteriorations appear on the exterior surface. As a preliminary step towards the establishment of a method for evaluating the structural performance of such a damaged RC slab, the purpose of this paper is to investigate the relationship between deteriorations and structural behaviors and to study the effect of an epoxy injection repair. For simplification, RC beams are prepared with artificial cracks that simulate deteriorations and these were made by the use of expansive agent. These beams are tested in flexure. Since the damage is volumetric, image analysis is useful to capture the two-dimensional deformations. It is shown that with different deterioration depths that is a part of the compression side of the beam or full of the height, there are differences about the deformation behaviors, the repair effects and the distributions of maximum and minimum principal strain.

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Hardware for Accelerating Anonymization Transparent to Network

Shohata S., Nakamura Y., Nishi H.

Proceedings - 2018 6th International Symposium on Computing and Networking, CANDAR 2018 （Proceedings - 2018 6th International Symposium on Computing and Networking, CANDAR 2018）     181 - 187 2018年12月

ISSN  9781538691823

　概要を見る

With the increase in the number of Internet of Things (IoT) devices, many applications using the data accumulated from IoT devices have been proposed. Consequently, privacy violation due to data disclosure is becoming a problem. Data anonymization is a technique for publishing data while preserving data privacy and is an effective method for solving the problem of privacy violation. There are several requirements for implementing anonymization systems suitable for IoT devices, where the amount of hardware and software resources, function extensibility, and processing throughput are limited. To satisfy these requirements, anonymization hardware for anonymizing data packets from IoT devices is proposed. The proposed hardware is allocated on the intermediate location of network and anonymizes the data packet stream from IoT devices transparently. The proposed anonymization process does not affect data communication or routing. This transparency allows an additional anonymization function to be installed on all types of IoT devices without modifying the devices. The proposed hardware allows IoT devices to anonymize the data packet stream. To reduce the latency and achieve transparent anonymization at a low cost, the proposed anonymization hardware was implemented using a field-programmable gate array. The throughput and latency of the testbed of the proposed hardware were 1,286 Mbps and 330 ns, respectively. The power consumption of the proposed hardware was lower than that for a software implementation.

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An overview of technologies for lower energy consumption in smart buildings

Moayedi S., AlJuheshi F., Almaghrebi A., Haase J., Nishi H., Tsang K., Alahmad M.

Proceedings: IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society （Proceedings: IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society）     4693 - 4698 2018年12月

ISSN  9781509066841

　概要を見る

In the last decade, the significant development of smart building technologies has led to the formation of various energy sensing and monitoring applications. Energy monitoring of appliances relies on techniques such as Intrusive Load Monitoring (ILM) and Non-Intrusive Load Monitoring (NILM). I L M is referred to a technique that a sensor installed for each load. In N I L M method, disaggregation of measured energy of all appliances at utility service entry is the main goal to provide a simple and cost-effective method of monitoring the appliances like sequence time domain reflectometry (STDR). This manuscript provides an overview of developments in energy consumption sensing and monitoring in three key areas of Internet of things (IoT), WSN and STDR for the advancement of smart building technology. This paper also provides some research directions for smart home of the future.

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TMk-anonymity: Perturbation-based data anonymization method for improving effectiveness of secondary use

Nakamura T., Nishi H.

Proceedings: IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society （Proceedings: IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society）     3138 - 3143 2018年12月

ISSN  9781509066841

　概要を見る

The recent emergence of smartphones, cloud computing, and the Internet of Things has brought about the explosion of data creation. By collating and merging these enormous data with other information, services that use information become more sophisticated and advanced. However, at the same time, the consideration of privacy violations caused by such merging is indispensable. Various anonymization methods have been proposed to preserve privacy. The conventional perturbation-based anonymization method of location data adds comparatively larger noise, and the larger noise makes it difficult to utilize the data effectively for secondary use. In this research, to solve these problems, we first clarified the definition of privacy preservation and then propose TMfc-anonymity according to the definition.

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Self-organizing map using classification method for services in multilayer computing environments

Iwai T., Ohno Y., Niwa A., Nakamura Y., Sakai K., Matsui K., Nishi H.

Proceedings: IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society （Proceedings: IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society）     4193 - 4198 2018年12月

ISSN  9781509066841

　概要を見る

The increasing amount of data running in cloud-computing environments has started inflating networks. To solve the problems caused by network inflation (e.g., latency and privacy), new types of computing environments with multiple layers have been proposed. However, service placement inside these multilayer computing environments has not been proposed. Nodes inside multilayer computing environments have different preferences, and the services deployed also have restrictions on deployment. Therefore, services must be placed carefully inside the computing environment. To place these services, we introduce a service classification method according to their properties and restrictions. However, when accommodating dynamic placement, rapid classification is needed to avoid serious damage caused by restriction changes. Therefore, we propose a classifying method using k-Nearest Neighbor Classification (k-NN). In addition, to accelerate the process, we use a dimension reduction method called Self-Organizing Maps (SOM) to preprocess the data. The proposed classification method is expected to be used as the primary step in service placement. The method will supply service placers with the identification of which layer services should be deployed.

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FROG: A Packet Hop Count based DDoS Countermeasure in NDN

Nakatsuka Y., Wijekoon J., Nishi H.

Proceedings - IEEE Symposium on Computers and Communications （Proceedings - IEEE Symposium on Computers and Communications）  2018-June   492 - 497 2018年11月

ISSN  9781538669501

　概要を見る

Named Data Networking (NDN) is a promising inter-networking paradigm that focus on content rather than hosts and their physical locations. In NDN Consumers issue Interests for Contents. Producers generate a content in response to each received interest and such content is routed back to the requesting consumer. When compared to IP, NDN brings advantages such as better throughput and lower latency, because routers are able to cache popular contents and satisfy interests for such contents locally. However, before being considered a viable approach, NDN should offer security services that are ideally better, but at least equivalent to current mechanisms in IP.In this regard, mechanisms to prevent DDoS are of paramount importance. In this work we propose FROG: a simple yet effective Interest Flooding Attack (IFA) detection and mitigation method. FROG runs on routers that are directly connected to NDN consumers and monitors packet hop counts. It then calculates mean and variance using stored hop counts to distinguish attackers from legitimate users. We use the NDN simulator ndnSIM to evaluate FROG's effectiveness. Our results show that FROG improves resilience against DDoS attacks. In particular, during an attack, legitimate users can still receive 75% of requested contents. Without FROG this number decreases to 50%.

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Improving Road Traffic Management by A Model-Based Simulation

Harahap E., Wijekoon J., Purnamasari P., Darmawan D., Ceha R., Nishi H.

Proceedings - 2018 4th International Conference on Science and Technology, ICST 2018 （Proceedings - 2018 4th International Conference on Science and Technology, ICST 2018）  2018年11月

ISSN  9781538658130

　概要を見る

Road traffic is a supporting medium that is essential to various means of land transportation that connect various locations and even large cities. Smooth traffic is a good parameter of the management of a city, also as a sign to determine the technological and economic development in the city. As the rate of civilization grows, as well as the number of people, the traffic becomes more crowded, so that congestion occurs in to an alarming level. The solution to solve the problem is by applying some methods as well as traffic engineering. However, implementing such methods without proper planning will lead to higher costs and lesser optimal results. In this article, we proposed a traffic simulation system called as 'LINTAS', a simulator tool in an attempt to resolve the traffic jam. The exact method and traffic engineering, before it is tested in a real situation, is first simulated through the LINTAS system, so that it can be known its effectiveness. LINTAS are built using the SimEvents toolbox and runs on MATLAB-Simulink software. The LINTAS simulator is performed based on the mathematical sciences, especially the field of queueing theory.

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Proposal of Feature Value Selection Method for Time-Critical Learning

Yuyama K., Nishi H.

IEEE International Conference on Emerging Technologies and Factory Automation, ETFA （IEEE International Conference on Emerging Technologies and Factory Automation, ETFA）  2018-September   1365 - 1371 2018年10月

ISSN  9781538671085

　概要を見る

The development of IoT has led to the creation of a data-enriched environment that enables data gathering by using distributed sensors and terminals. However, in this environment, the cost of data analysis has increased. Machine learning has gained attention for reducing the cost because enabling automatic data analysis, as well as multidimensional data, is expected. However, for enormous data, such as Big Data, we still have to pay costs. Therefore, selecting feature values when using machine learning technology is essential, especially as inputs of a classifier. Selecting the feature values increases its estimation accuracy. Moreover, the time cost, as well as calculation cost, needs consideration for the actual time-critical use of machine learning, especially in its learning process. Therefore, in this study, we proposed an algorithm that selected suitable feature values in required time. The proposed method consists of two stages: stepwise input selection stage using ANOVA and feature deletion stage according to the contribution rate of the features to estimate accuracy. These selection and deletion processes continue until the required processing time. We confirmed the efficiency of the proposed method by using an environment of a crystallization process in a factory and a household's occupancy estimation. A comparison with the original stepwise input method proved that the proposed method improved the estimation accuracy by 2% and 5% in the estimation of the substance amount of the crystallization process and household's occupancy, respectively.

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Request Distribution for Heterogeneous Database Server Clusters with Processing Time Estimation

Omori M., Nishi H.

Proceedings - IEEE 16th International Conference on Industrial Informatics, INDIN 2018 （Proceedings - IEEE 16th International Conference on Industrial Informatics, INDIN 2018）     278 - 283 2018年09月

ISSN  9781538648292

　概要を見る

Recently, data traffic on the Internet has increased due to the rapid growth of various Internet-based services. The convergence of user requests means that servers are overloaded. To solve this problem, service providers generally install multiple servers and distribute requests using a load balancer. The existing load balancing algorithms do not estimate the size of the load of unknown requests. However, the requested contents are heterogeneous and complex, so the size of the load is dependent on the servers and the contents of the requests. In this study, we propose a load balancing algorithm that distributes the requests based on estimates of the processing time, which avoids mismatches between the characteristics of servers and the request contents. The processing time for requests is estimated based on the requested contents by online machine learning, and a strategy to cover the latency of machine learning is proposed and partially conducted. To test the algorithm, we built a model of multiple database servers and performed an experiment using real log data for database requests. The simulation results showed that the proposed algorithm reduced the average processing time for requests by 94.5% compared with round robin and by 28.3% compared with least connections.

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Task Allocating Service-oriented Network for Smart Community Applications

Kinoshita S., Hiroaki N.

Proceedings - IEEE 16th International Conference on Industrial Informatics, INDIN 2018 （Proceedings - IEEE 16th International Conference on Industrial Informatics, INDIN 2018）     140 - 145 2018年09月

ISSN  9781538648292

　概要を見る

Smart community is the extended concept of the smart grid. Many services, including, but not limited to infrastructure services are deployed in the smart community. Some of the services in the smart community are time critical and require low latency between requests and responses. However, commonlyused cloud computing architecture is not designed with an emphasis on the latency. Therefore, the network architecture for low latency required services are necessary. This paper proposes a serviceproviding network for smart communities. In the proposed network, service-oriented router is utilized to provide the service in intermediate nodes between a cloud server and an end node. By responding to therequest at the intermediate node instead of the cloud where is close to the end devices, the latency is reduced. To demonstrate the feasibility of the proposed network, a simulation of the proposed network with two time-critical services were carried out in the network simulator ns-3. The ancillary service and intersection accident avoidance service are chosen to be considered in the simulation since they are attention-grabbing time-critical services for the smart community. The reduction of both latency and variation of the latency in both services was observed in the simulation. For the ancillary service, the proposed method has reduced the average latency to 10.85 ms that is low enough to provide stable service. The result shows the feasibility of application task allocation between intermediate SoR nodes based on a latency requirement in the smart community.

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Indoor Occupancy Estimation via Location-Aware HMM: An IoT Approach

Yoshida M., Kleisarchaki S., Gtirgen L., Nishi H.

19th IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks, WoWMoM 2018 （19th IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks, WoWMoM 2018）  2018年08月

ISSN  9781538647257

　概要を見る

Indoor occupancy estimation is a critical analytical task for several applications (e.g., social isolation of elderlies). The proliferation of Internet of Things (IoT) devices enabled the occupancy estimation, as it provided access to a mass amount of data. Several works have been proposed exploiting the IoT Passive Inference (PIR) or environmental (e.g., CO2) features. These works however are traditionally selecting the feature space at the learning phase and passively using it over time. Hence, they ignore the dynamics of indoor occupancy, such as the location of the occupant or his motion patterns, leading to a decreasing accuracy over time. In this paper, we study those dynamics and show that motion patterns, along with environmental features favor the occupancy estimation. We design a Location-Aware Hidden Markov Model (HMM), which dynamically adapts the feature space based on the occupant's location. Our experiments on real data show that Location-Aware HMM can reach up to 10% better accuracy than Conventional HMM.

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Building Thermal Performance Assessments Using Simple Sensors for the Green New Deal in Japan

Sakuma Y., Nakajo Y., Nishi H.

IEEE International Symposium on Industrial Electronics （IEEE International Symposium on Industrial Electronics）  2018-June   691 - 696 2018年08月

ISSN  9781538637050

　概要を見る

The development of smart communities has provided additional sources of data for innovative new services. In residential areas, Home Energy Management Systems (HEMS) provide a data stream from the home, including room temperature and the status of heating, ventilation, and air conditioning (HVAC) appliances. The data is of interests to both residents and utilities for energy saving purposes. The Green New Deal is a scheme that subsides building improvement to increase energy efficiency by insulating buildings and introducing energy-saving electric appliances. However, the scheme is often criticized due to high installation costs. Therefore, a simple and low cost method to assess building thermal performance is important to select those homes, that can benefit the most from the scheme. In this study, a novel method for assessing building thermal performance based on HEMS data is proposed. The thermal equilibrium of a house is modeled to state the system identification problem to estimate the unknown parameters, such as heat transfer coefficient and heat capacity of a house. The unknown parameters are estimated by using Kalman Filter. In this way, the thermal performance of building can be assessed remotely while residents live their daily lives. Estimated parameters are then validated by considering those elements affected by the behavior of residents. The proposed method was found to estimate the heat transfer coefficient well and thus aid in effectively targeting Green New Deal projects.

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スマートシティインフラの展望

西 宏章

技術雑誌「スマートグリッド」特集エネルギーを中心とした情報収集・管理技術 大河出版 2018年07月

Data prediction for response flows in packet processing cache

Yamaki H., Nishi H., Miwa S., Honda H.

Proceedings - Design Automation Conference （Proceedings - Design Automation Conference）  Part F137710 2018年06月

ISSN  9781450357005

　概要を見る

We propose a technique to reduce compulsory misses of packet processing cache (PPC), which largely affects both throughput and energy of core routers. Rather than prefetching data, our technique called response prediction cache (RPC) speculatively stores predicted data into PPC without additional access to the low-throughput and power-consuming memory (i.e., TCAM). RPC predicts the data related to a response flow at the arrival of the corresponding request flow, based on the request-response model of internet communications. RPC can improve the cache miss rate, throughput, and energy-efficiency of PPC systems by 15.3%, 17.9%, and 17.8%, respectively.

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Time slotted channel hopping scheduling based on the energy consumption of wireless sensor networks

Matsui T., Nishi H.

Proceedings - 2018 IEEE 15th International Workshop on Advanced Motion Control, AMC 2018 （Proceedings - 2018 IEEE 15th International Workshop on Advanced Motion Control, AMC 2018）     605 - 610 2018年06月

ISSN  9781538619469

　概要を見る

Wireless Sensor Nnetworks (WSNs) are becoming increasingly widespread owing to the introduction of the Internet of Things (IoT) and the networks' comparatively low cost and usability. WSNs are usually battery-powered, owing to their low power consumption, which however limits their computational performance. The lifetime of a WSN strongly depends on its communication-related power consumption. Time Slotted Channel Hopping (TSCH) solves the problem of power consumption by featuring both time-division and frequency- division multiplexing in the system's Media Access Control (MAC) layer. In this paper, Pruning-based Coloring Scheduling (PRCOS) is proposed, which is an algorithm for TSCH scheduling that accounts for the power consumption to extend the system's lifetime. Using mathematical analysis, we show that the proposed algorithm decreases the transfer time and energy consumption by factors of 0.43 and 0.57, respectively, compared with existing algorithms.

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Slightly-slacked dropout for improving neural network learning on FPGA

Sawaguchi S., Nishi H.

ICT Express （ICT Express）  4 （ 2 ） 75 - 80 2018年06月

ISSN  2405-9595

　概要を見る

Neural Network Learning (NNL) is compute-intensive. It often involves a dropout technique which effectively regularizes the network to avoid overfitting. As such, a hardware accelerator for dropout NNL has been proposed; however, the existing method encounters a huge transfer cost between hardware and software. This paper proposes Slightly-Slacked Dropout (SS-Dropout), a novel deterministic dropout technique to address the transfer cost while accelerating the process. Experimental results show that our SS-Dropout technique improves both the usual and dropout NNL accelerator, i.e., 1.55 times speed-up and three order-of-magnitude less transfer cost, respectively.

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Information and communication platform for providing smart community services: System implementation and use case in Saitama city

Nishi H.

Proceedings of the IEEE International Conference on Industrial Technology （Proceedings of the IEEE International Conference on Industrial Technology）  2018-February   1375 - 1380 2018年04月

ISSN  9781509059492

　概要を見る

Smart communities, smart cities, smart towns, and similar smart terminologies are trending recently, along with the Internet of Things (IoT) and the Cloud, as popular new information and communication technologies (ICTs). This paper proposes a synergistic solution to urbanization problems from a technological perspective that is beneficial both to residents and to local government. Case studies of a smart community implementation in Saitama city are also provided, from the viewpoint of integrated smart infrastructure services.

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An Information Platform for Smart Communities Realizing Data Usage Authentication and Secure Data Sharing

Niwa A., Nishi H.

Proceedings - 2017 5th International Symposium on Computing and Networking, CANDAR 2017 （Proceedings - 2017 5th International Symposium on Computing and Networking, CANDAR 2017）  2018-January   119 - 125 2018年04月

ISSN  9781538620878

　概要を見る

The deployment of Information and Communication Technology in existing infrastructure has increased interest in smart communities. Smart communities provide various services such as ancillary services, road traffic information management, and health care management. Each service has distinctive characteristics such as processing delay, the need for anonymity, computational cost, and the amount of data. Therefore, to optimize the system, locations to provide these services should be organized. In addition, secondary use of personal data is assumed in smart communities. Thus, measures to provide privacy protection should be implemented. In this paper, a new information platform is proposed, which allows management of a user's privacy policy, management of data usage, smooth data sharing, and adequate service location organization by introducing the concept of 'Relationship.' Response time associated with organization was evaluated on the implemented platform to ensure the feasibility of the proposed method, and it was about 15 minutes when the number of Relationships is 12,800.

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Blind Watermarking Method for Anonymized Data

Ohno Y., Iwai T., Nishi H.

Proceedings - 2017 5th International Symposium on Computing and Networking, CANDAR 2017 （Proceedings - 2017 5th International Symposium on Computing and Networking, CANDAR 2017）  2018-January   139 - 145 2018年04月

ISSN  9781538620878

　概要を見る

The secondary use of data in consideration of individual privacy has been gaining attention. Data anonymization needs to be applied to enable both secondary use and privacy protection. In distributing anonymized data, there is a concern that data users might re-distribute the data to a third party without permission. To tackle this issue, a watermarking technique that correlates data users (IDs) with anonymized data has been studied. In existing studies, a non-blind detection method has been employed to obtain the IDs; however, the problem is the use of original data in the detection, which deteriorates the applicability. In this paper, a watermarking technique in combination with a blind detection method is proposed. We evaluate and compare the proposed watermarking method with an existing non-blind method in terms of information loss, tolerance against attacks, and the processing time of watermarking and detection.

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A privacy-preserving sharing method of electricity usage using self-organizing map

Nakamura Y., Harada K., Nishi H.

ICT Express （ICT Express）  4 （ 1 ） 24 - 29 2018年01月

研究論文（学術雑誌）, 査読有り,  ISSN  2405-9595

　概要を見る

Smart meters for measuring electricity usage are expected in electricity usage management. Although the relevant power supplier stores the measured data, the data are worth sharing among power suppliers because the entire data of a city will be required to control the regional grid stability or demand–supply balance. Even though many techniques and methods of privacy-preserving data mining have been studied to share data while preserving data privacy, a study on sharing electricity usage data is still lacking. In this paper, we propose a sharing method of electricity usage while preserving data privacy using a self-organizing map.

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Improving energy efficiency in data centers by controlling task distribution and cooling

Nakajo Y., Athavale J., Yoda M., Joshi Y., Nishi H.

ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018 （ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018）  2018年

ISSN  9780791851920

　概要を見る

The rapid growth in cloud computing, the Internet of Things (IoT), and data processing via Machine Learning (ML), have greatly increased our need for computing resources. Given this rapid growth, it is expected that data centers will consume more and more of our global energy supply. Improving their energy efficiency is therefore crucial. One of the biggest sources of energy consumption is the energy required to cool the data centers, and ensure that the servers stay within their intended operating temperature range. Indeed, about 40% of a data center’s total power consumption is for air conditioning[1]. Here, we study how the server air inlet and outlet, as well as the CPU, temperatures depend upon server loads typical of real Internet Protocol (IP) traces. The trace data used here are from Google clusters and include the times, job and task ID, as well as the number and usage of CPU cores. The resulting IT loads are distributed using standard load-balancing methods such as Round Robin (RR) and the CPU utilization method. Experiments are conducted in the Data Center Laboratory (DCL) at the Georgia Institute of Technology to monitor the server outlet air temperature, as well as real-time CPU temperatures for servers at different heights within the rack. Server temperatures were measured by on-line temperature monitoring with Xbee, Raspberry PI, Arduino, and hot-wire anemometers. Given that the temperature response varies with server position, in part due to spatial variations in the cooling airflow over the rack inlet and the server fan speeds, a new load-balancing approach that accounts for spatially varying temperature response within a rack is tested and validated in this paper.

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On the effectiveness of using network device state information for network path selection

Wijekoon J., Amunugama D., Nishi H.

Procedia Computer Science （Procedia Computer Science）  130   134 - 141 2018年

　概要を見る

Network path selection defines the methodology of selecting the best routes and forwarding traffic in a network service provider (NSP). NSPs use routing protocols that are optimized for a single arbitrary metric (i.e., administrative weight), which is commonly calculated according to the link state information, to select network paths. Despite the advantages, link-state protocols lack the ability to select network paths by considering the states of network devices such as the effect of routers for network path selection. Apparently, studying possible techniques for selecting network paths based on the state information of network devices, e.g., routers, has become obligatory. This paper studies the effectiveness of using network device state information for network path selection by presenting the Extended Server Link Router state Routing Protocol (ESLR). ESLR uses the state information of network devices as parameters to calculate a composite route metric; ESLR selects the network paths based on the cumulative propagation delay. By simulating ESLR using an ISP topology, the proposed protocol is examined for the effectiveness of using network device state information for network path selection.

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On the Effectiveness of IP-Routable Entire-Packet Encryption Service over Public Networks (November 2018)

Tennekoon R., Wijekoon J., Nishi H.

IEEE Access （IEEE Access）  6   73170 - 73179 2018年

ISSN  2169-3536

　概要を見る

The Internet is an unsecured public network accessed by approximately half of the world population. There are several techniques, such as cryptography, end-to-end encryption, and tunneling, used to preserve data security and integrity and to reduce information theft. This is because the security of data transmission over public networks is an ever-questionable issue. However, none of the above techniques are capable of providing the flexibility of changing either the algorithm or its key at the intermediary routers according to the requirements of stakeholders, e.g., ISPs or Internet users. Although the transmitted data are encrypted and unreadable, the metadata contained in the packet headers are readable during traversal. Nonetheless, service-based Internet architectures, e.g., IoT architectures, demand the analysis the data streams at the intermediary routers to provide smart services such as strengthening the security of the data streams. To this end, this paper proposes a method to use service-oriented routers for providing secure data transmission by encrypting data packets including the header and trailer information. A prototype of the proposed method is implemented on the ns-3 simulator, and this paper discusses the implementation notes and evaluation of the test results. The test results demonstrate that there is only an average processing cost of 180.14/191.35, 213.96/257.41, 157.56/170.68, and 235.48/ 249.49~\mu \text{s} for encrypting the total encrypted combined packets/total encrypted separate packets using IDEA, DES, AES-GCM, and AES-CTR encryption algorithms, respectively, with a 256-bit key space. This is significantly lower than the tolerable transmission delay (150 ms) defined by the ITU-T.

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Transcriptomic features of KRT7 positive cells derived from BMP4-treated human induced pluripotent stem cells (hiPSCs)

Hiroaki Nishi

Human Reproduction 2018年

Anonymization method based on sparse coding for power usage data

Keiya Harada, Yuta Ohno, Yuichi Nakamura, Hiroaki Nishi

2018 IEEE 16TH INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS (INDIN) （IEEE）     571 - 576 2018年

査読有り,  ISSN  1935-4576

　概要を見る

In recent years, there have been rapid increases in the number of network-connected devices such as computers, smartphones, and Internet of Things devices. Thus, large amounts of data have been accumulated such as locational data, website search histories, and power usage data. These data are used in various types of services. However, these data cannot he used easily for secondary purposes in some countries because of privacy problems. Therefore, privacy protection is necessary to apply these data in secondary uses where data anonymization is the usual solution. Many conventional methods are used for anonymizing power usage data, but the conventional method has three problems. First, it cannot anonymize time-series data. Second, the information loss is so large in the conventional method that the anonymized data are no longer suitable for secondary uses. Third, the conventional method cannot preserve the type of electrical appliance used. In this study, we propose a method for anonymizing power demand data, where sparse coding is used to solve the three problems that affect the conventional method. The proposed method can anonymize time series-data and it allows data to be analyzed at a chosen time. The proposed method was used to anonymize power usage data from the Urban Design Center Misono (UDCMi) and the experimental error rate decreased compared with the conventional method. The dictionary produced using the proposed method represents the electrical appliance data.

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Presence of Visceral Adiposity Fans the Flame of Mortality Amongst Sarcopenic Patients with Liver Cirrhosis

Hiroaki Nishi

Hepatology 2018年

Analysis of batteries in the built environment: An overview on types and applications

Jan Haase, Fares AlJuheshi, Hiroaki Nishi, Joern Ploennigs, Kim Fung Tsang, Nasser Aljuhaishi, Mahmoud Alahmad

Proceedings IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society （IEEE）  2017-January   8113 - 8118 2017年12月

ISSN  1553-572X

　概要を見る

© 2017 IEEE. Recent trends in the applications of batteries in the built environment are improving the efficiency of batteries and lowering costs. This paper introduces various types of battery technologies such as sodium sulfur, lithium ion, flow and lead acid batteries and discusses their models. Various applications of batteries such as adaptive battery systems, Battery Electrical Vehicles (BEVs), Battery Energy Storage Systems (BESS), the Internet of Things (IoT), and Smart Grid and Smart Environment applications are also discussed. In their selection and use of batteries, scholars are ultimately looking to maximize occupant comfort whilst keeping costs low and optimizing the energy efficiency of buildings. This paper will provide a review of current trends in this field.

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Efficient energy utilization based on task distribution and cooling airflow management in a data center

Yusuke Nakajo, Tomomichi Noguchi, Hiroaki Nishi

Proceedings IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society （IEEE）  2017-January   7171 - 7176 2017年12月

査読有り,  ISSN  1553-572X

　概要を見る

© 2017 IEEE. With the recent emergence of smartphones, cloud computing, and the Internet of Things (IoT), our society has become more dependent on the Internet. In these circumstances, increasing energy consumption in data centers is becoming a crucial problem worldwide and data center managers are required to run them efficiently in terms of energy consumption. This study aims to reduce cooling airflow energy by achieving appropriate task distribution and adding a shutter control system, which reduces the energy consumption of an air-conditioner. In most cases, servers tend to be unnecessarily cooled at low temperatures, even when their exhaust temperatures are not high. Our proposed method solves this problem by using shutter control and introducing a task allocation method. We built an experimental rack model and implemented our proposed control system, validating it with a real HTTP data request. The results show that our experimental system reduces the cooling airflow energy by 4.4%.

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Novel infrastructure with common API using docker for scaling the degree of platforms for smart community services

Tatsuki Miura, Janaka L. Wijekoon, Shanaka Prageeth, Hiroaki Nishi

Proceedings - 2017 IEEE 15th International Conference on Industrial Informatics, INDIN 2017 （IEEE）     474 - 479 2017年11月

ISSN  1935-4576

　概要を見る

© 2017 IEEE. The development of smart communities has diversified not only service execution platforms but also the resolvers of multiple service requirements, each of which has different requirements in terms of processing delay, anonymity, computational cost, the amount of data at a given level of granularity, etc. To meet these requirements, an infrastructure that easily performs service migration and provides services with the correct processing nodes using IP-independent distributed processing methods such as Authorized Stream Contents Analysis (ASCA) is becoming a pressing need of smart communities. ASCA is an advanced method of analyzing packet streams and filtering necessary packet streams according to the marker tags in the contents of the streams under the Opt-In manner. Moreover, smart communities require that every service be able to perform ASCA and gather necessary data because of the diversified nature of the services. Consequently, in this paper, we have implemented a service infrastructure using a Docker container that facilitates service migration and provides services with a common Application Programming Interface (API) using ASCA. The API provides a process throughput of over 60 Gbps on a Docker container using Zero-Copy mechanism.

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スマートコミュニティにおける二次利用のためのBlind電子透かし手法の提案と検討 (VLSI設計技術) -- (デザインガイア2017 : VLSI設計の新しい大地)

大野 雄太, 仁和 瞭, 西 宏章

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 （電子情報通信学会）  117 （ 273 ） 191 - 196 2017年11月

ISSN  0913-5685

糖類の晶析データを用いた特徴量の重要度を決定する手法の提案と評価 (情報システム研究会 知識抽出技術と情報システム、その他一般)

湯山 要海, 吉田 将大, 服部 一裕, 村並 広章, 田中 基雅, 西 宏章

電気学会研究会資料. IS （電気学会）  2017 （ 51 ） 1 - 4 2017年11月

Decentralized hybrid switching control of multiconverter MVDC shipboard power systems

Dominik Mildt, Ryogo Kubo

Proceedings of the 43rd Annual Conference of the IEEE Industrial Electronics Society, IECON 2017 2017年10月

査読有り

スマートコミュニティとは何か –実証例から見る社会問題解決策としての可能性-

西 宏章

Journal of Human and Environmental Symbiosis, 環境共生 31   3 - 12 2017年09月

研究論文（学術雑誌）

スマートコミュニティとは何か : 実証例から見る社会問題解決策としての可能性

西 宏章

環境共生 = Journal of human and environmental symbiosis （日本環境共生学会本部事務局）  31   3 - 12 2017年09月

ISSN  1346-3489

Time-series decomposition of power demand data to extract uncertain features

Tomoya Imanishi, Masahiro Yoshida, Janaka Wijekoon, Hiroaki Nishi

IEEE International Symposium on Industrial Electronics （IEEE）     1535 - 1540 2017年08月

ISSN  2163-5137

　概要を見る

© 2017 IEEE. The spread of smart meters means that a large amount of power demand information from private houses is being collected around the world. Owing to the development of smart city infrastructure, the use of standardized frameworks for extracting features from power demand information has become vital. In this paper, we propose a novel decomposition approach useful for extracting feature values from power demand information from a house. Energy consumption was monitored for multiple houses for one month in Japan with a sampling duration of 30 minutes, which is a standard sampling time of smart meters in Japan. First, periodic characteristics were detected for 24 hours based on autocorrelation analysis. Then, the monitored information was decomposed into four components: standby power, trends, and periodic and residual parts. The distribution of the residual part is similar to a Gaussian distribution, so the behavior of the residual part was parameterized using variance and average. Trend, periodic, and residual components were clustered by means of k-means clustering in order to aggregate the difference in behaviors. There was no periodic component in the residual part according to auto-correlation analysis. Nevertheless, some clusters had a relatively large variance, which means that abnormal power demand occurred frequently in datasets. The amount of variance and climate correlation was analyzed, and the fact detected that large scale events disturb usual daily life-styles, from the viewpoint of energy usage. Last, these features were compared with actual customer information. In the evaluation, family structure and floor space were utilized to prove the effectiveness of the proposed decomposition approach. The evaluation proved that this decomposition method could extract uncertainty features from power demand information.

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Feature extraction and background information detection method using power demand

Masahiro Yoshida, Tomoya Imanishi, Hiroaki Nishi

IEEE International Symposium on Industrial Electronics （IEEE）     1336 - 1341 2017年08月

ISSN  2163-5137

　概要を見る

© 2017 IEEE. Recently, many electricity retailers have been aggregating consumer power demand information from smart meter infrastructure, and applications that utilize these data are widely studied. For example, the estimation of customers' background information using their power demand information has attracted much interest; this information can be utilized in the marketing field for background-targeted advertising. In order to utilize power demand information effectively, an appropriate feature extraction method must be applied. In this paper, appropriate data extraction methods specific to power demand information are proposed. In the experiment, power demand data for Kawasaki city were used, and 19 feature data were extracted using the proposed method. The utility of the extracted features was assessed through the performance of classification estimation for two background information types, family structure and floor space. The classification problems are solved by applying two typical machine-learning algorithms, the support vector machine and k-nearest neighbor. In particular, analysis of variance (ANOVA) was applied to the 19 feature data, which were ranked according to the F value. Then, the n (n = [1, 2, 19]) best feature data were used as the input step by step, and the score for each condition was computed to derive the best feature set. According to the results, some of the feature data were considered to be irrelevant, and the best feature data set was successfully selected. Furthermore, thee scores when raw data were input were also computed and compared with the scores when the best feature data set was used. As a result, the performance was better when using processed data instead of raw data.

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Novel Method to Watermark Anonymized Data for Data Publishing

Yuichi Nakamura, Yoshimichi Nakatsuka, and NISHI HIROAKI

IEICE Transactions on Information and Systems （IEICE）  E100-D （ 8 ） 1671 - 1679 2017年08月

研究論文（学術雑誌）,  ISSN  0916-8532

　概要を見る

Copyright © 2017 The Institute of Electronics, Information and Communication Engineers. In this study, an anonymization infrastructure for the secondary use of data is proposed. The proposed infrastructure can publish data that includes privacy information while preserving the privacy by using anonymization techniques. The infrastructure considers a situation where ill-motivated users redistribute the data without authorization. Therefore, we propose a watermarking method for anonymized data to solve this problem. The proposed method is implemented, and the proposed method's tolerance against attacks is evaluated.

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Implementation and Evaluation of an FPGA-based Network Data Anonymizer

Yuichi Nakamura, Sota Sawaguchi and HIROAKI NISHI

Journal of Information ProcessingIEEJ Transactions on Electrical and Electronic Engineering, IEEJ Trans 2017; 12(S1); S134-S140 （Wiley Online Library.）  12 （ S1 ） S124 - S140 2017年06月

共著

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Effectiveness of Service-oriented Router for ISP-CDN Collaboration

Janaka L. Wijekoon, Eriwn H. Harahap, Rajitha L. Tennekoon,NISHI HIROAKI

Journal of Information Processing （Information Processing Society of Japan）  25 （ 25 ） 44 - 45 2017年01月

研究論文（学術雑誌）, 査読有り,  ISSN  0387-5806

　概要を見る

© 2017 Information Processing Society of Japan. This article discusses a novel method to strengthen the collaboration between Internet service providers (ISPs) and content delivery networks (CDNs). CDNs are becoming the primary data delivery method in information communication technology environments because information sharing via networks is becoming the driving force of the future Internet. Moreover, it is anticipated that network routers will be equipped with additional processing power and storage modules for providing efficient end-user services. Consequently, this article studies the effectiveness of introducing a Service-oriented Router (SoR) to strengthen the ISP-CDN collaboration to leverage DNS-based request redirection in CDNs. In contrast, the proposed method yields better performance in user redirection and network resource utilization, suggesting that using SoR may a future business model which addresses adequate ISP-CDN collaboration.

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Feature expression of frequency transform regarding daily power demand information

Tomoya Imanishi, Rajitha Tennekoon, Hiroaki Nishi

Proceedings of the 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017 （Association for Computing Machinery, Inc）     23 - 23 2017年01月

査読有り

　概要を見る

© 2017 ACM. Owing to the introduction of an energy-monitoring device called the "smart meter," a large amount of power-demand information regarding private houses is being stored around the world through the development of smart grids. Such electric consumption data include a variety of features related to the structure of the customer's home, as well as their family structure and lifestyle. To capture the meaningful features from the power-demand information, a proper extraction method should be considered such as a discrete Fourier transform (DFT) or discrete cosine transform (DCT). This paper proposes the use of two frequency analysis methods, i.e., DFT and DCT, toward power-demand information. The converted power-demand information is transformed using three expression methods. A power-demand dataset was gathered from more than 100 houses in Yokohama, Japan, over a two-year period. The numbers of feature values in these three expression methods were compared by estimating the floor space of each customer's house with two support vector classification (SVC) values using both linear and RBF kernels. As a result, the proposed expression method performed better than the other two feature expression methods. The mean accuracy of this expression method is better than the other two by 20%, and the highest level of accuracy in terms of the floor-space estimation is greater than 95% when using liner SVC (L2-SVC). The accuracy shows a distribution of 50% to 100% regardless of the number of selected frequencies transformed using a DFT and DCT.

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Temperature-based request distribution for effective CRAC and equipment life-cycle extension

Yusuke Nakajo, Hiroaki Nishi

ASME 2017 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2017, collocated with the ASME 2017 Conference on Information Storage and Processing Systems （AMER SOC MECHANICAL ENGINEERS）  2017年

査読有り,  ISSN  2378-8267

　概要を見る

© 2017 ASME. With the growth of Internet-based services, data centers must deal with increasing data traffic. Load-balancing technologies can help data centers process data effectively and stably; however, the current load-balancing methods do not take into account the heat generated by servers. Excessive heat can increase the failure rate of IT devices and the energy consumption of air conditioning systems, both of which lead to higher data center maintenance costs. This paper aims to simultaneously increase the coefficient of performance (COP) of the data center's air-conditioning equipment and decrease the semiconductor-based equipment failure rate. To do so-and, consequently, reduce the operation and maintenance costs-we propose a novel request distribution system based on servertemperature and evaluate the proposed system by creating a thermal model of a data center. As a result, it is suggested that using the proposed load-balancing method the semiconductor failure rate can be reduced by 32 % when compared with the common round-robin distribution method, and by 19 % when compared with a load-balancing method based on CPU utilization. Moreover, the COP of the air-conditioning equipment obtained with the proposed method is recognized to be higher than those obtained with either the round-robin or the CPUutilization- based methods.

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Coordination middleware for secure wireless sensor networks

Yuichi Nakamura, Maxime Louvel, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）  0   6931 - 6936 2016年12月

査読有り,  ISSN  1553-572X

　概要を見る

© 2016 IEEE. Wireless sensor networks (WSNs) are implemented in various Internet-of-Things applications such as energy management systems. As the applications may involve personal information, they must be protected from attackers attempting to read information or control network devices. Research on WSN security is essential to protect WSNs from attacks. Studies in such research domains propose solutions against the attacks. However, they focus mainly on the security measures rather than on their ease in implementation in WSNs. In this paper, we propose a coordination middleware that provides an environment for constructing updatable WSNs for security. The middleware is based on LINC, a rule-based coordination middleware. The proposed approach allows the development of WSNs and attaches or detaches security modules when required. We implemented three security modules on LINC and on a real network, as case studies. Moreover, we evaluated the implementation costs while comparing the case studies.

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Shutter control for cooling air flow management in data center servers

Tomomichi Noguchi, Janaka Wijekoon, Yogendra Joshi, Minami Yoda, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     5591 - 5596 2016年12月

査読有り,  ISSN  1553-572X

　概要を見る

© 2016 IEEE. The growth of energy consumption in data centers is becoming one of the significant problems all over the world. The power usage of IT devices and air-conditioning (AC) units accounts for up to three-quarters of total energy consumption in typical data centers. This study discusses the effectiveness of using shutter-controlled air flow management to control cold air flow into the servers. It can impact the power consumption of both, the servers and the AC units. A raised floor data center has two types of aisles - cold and hot. In most cases, excessive volumes of cold air are pumped into the servers using cold aisles. We are proposing the utilization of a shutter to control the air flow and reduce wastage while preventing damage due to increased CPU temperature. The shutter is intended to control the air flow and maintain the temperature appropriately according to the workload of the servers. We evaluated the proposed system for controlling the flow of air into the servers. The results show that cold air volumes can be reduced by up to 92% while maintaining appropriate control of CPU temperature.

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Analysis and implementation of WSN with Route Selection considering Energy Consumption

Tadanori Matsui, Hiroaki Nishi

2016 IEEE International Conference on Smart Grid Communications, SmartGridComm 2016 （IEEE）     1 - 7 2016年12月

査読有り,  ISSN  2373-6836

　概要を見る

© 2016 IEEE. In a smart city infrastructure, Wireless Sensor Network (WSN) is the most important technique to collect environmental data to provide services. WSN becomes more and more popular research area because of its usefulness and huge demand. Since energy resource in WSN is limited, the design of a WSN system should consider energy effectiveness as well as fulfilling application requirements. The effectiveness of the system totally depends on its application and hardware specifications; thus, the routing algorithm of WSN must be optimized to achieve the energy effective communication. The proposed algorithm Energy Consumption-oriented Route Selection (ECORS) is the route selection algorithm attempting to prolong the system lifetime, especially for data collection application. In this paper, the suitable mechanism for data collection is proposed with focusing on implementation, which includes the actual packet transactions mechanism and the improved function for selecting routes in an assumed environment. By modifying the parameters with the thought of implementation, proposed mechanism can extend the lifetime 2.03 times longer than the fixed routing scenario. Furthermore, the simulation result is analyzed in detail with focusing on state of charge variation on each node. Moreover, the new indicator to depict the relationship between lifetime expansion rate and parameters used for the algorithm is introduced. By using this indicator, lifetime expansion rate can be assumed without simulation, which is helpful for implementation.

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Automated generation method of recommendation for effective energy utilization as a HEMS service

Takahiro Hosoe, Tadanori Matsui, Hiroaki Nishi

2016 IEEE International Conference on Smart Grid Communications, SmartGridComm 2016 （IEEE）     74 - 79 2016年12月

査読有り,  ISSN  2373-6836

　概要を見る

© 2016 IEEE. Smart Grids and Home Energy Management System (HEMS) have been propagated by energy liberalization, and there is a demand for services, which are based on analysis of energy consumption data. For instance, a recommendation on effective utilization of home appliances in order to reduce power consumption. However, it is computationally expensive to analyze data in order to provide an energy-saving handbook, which recommends low-carbon life and is written in a natural language. This kind of service is called recommendation service. Existing automated recommendation services are constrained by the range of data usage, especially when using local information, such as status of surroundings, weather, residents' behavior, etc. The proposed method of automated generation of recommendation considers this background knowledge and information by using clustering methods. The result of a questionnaire which compared a handmade recommendation with the proposed fully-automated recommendation showed that 80% of the residents selected the automated recommendation because of its appropriateness.

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Feature extraction and classification using power demand information

Tomoya Imanishi, Rajitha Tennekoon, Hiroaki Nishi

2016 IEEE International Conference on Smart Grid Communications, SmartGridComm 2016 （IEEE）     92 - 97 2016年12月

査読有り,  ISSN  2373-6836

　概要を見る

© 2016 IEEE. Electrical load monitoring, by means of a smart meter, is getting more and more popular these days. Power demand information from smart meters is drawing attention among researchers, since it could be applied for power demand control. Providing attractive services with smart meters encourage electricity retailers to utilize demand side management, which could be a solution for energy-related problems in our society. In this paper, a novel service is proposed by classifying private information from the household electricity usage. The private information is estimated using feature vectors extracted from time series analysis of power demand information. In order to extract feature vectors effectively, two extraction methods were proposed: simple statistical method, and Discrete Fourier Transform (DFT) based extraction method. Then, Support Vector Machines (SVMs) classifier is carried out after the optimization of hyper-parameters. As the estimated information, both family structure and floor space were selected. The classification result is evaluated using F-measure and accuracy. As a result, the accuracy of DFT-based classification was superior to the statistical method for detecting the floor space in a house.

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Influence of noise-based perturbation on recommendation application

Yuichi Nakamura, Takahiro Hosoe, Hiroaki Nishi

2016 IEEE International Conference on Smart Grid Communications, SmartGridComm 2016 （IEEE）     14 - 19 2016年12月

査読有り,  ISSN  2373-6836

　概要を見る

© 2016 IEEE. A typical service provided by a Smart City is a Home Energy Management System (HEMS), an automated system that uses sensor networks to collect usage of home appliances and devices such that the collected data are accessible by the local government. For example, Smart meters, installed within individual homes, can send measures of electricity consumption for analysis in the context of the global community. Such data can be used by a forecasting tool to avoid electrical outage and improve the overall management of electricity usage by the community. However, the data collected may be protected by individual privacy laws and it is possible that the network may be violated by intruders to gain access to the lifestyle of individuals within their home. For example, an intruder may be able to identify active appliances and the number of individuals present within the residence. There is a requirement to protect the data emanating from these sensors to preserve this individual privacy information. Thus, a data concierge service capable of analyzing individual HEMS data is required; such a service would improve the lifestyle by allowing access to HEMS data by a third-party analyst. Although such a service may not require raw data, one must evaluate the trade-off between the preservation of privacy information and the effectiveness of the impact of the data services on the entire community. In this paper, we implemented a prototype application in conjunction with two noise-based perturbations. The application recommends improvements to household electricity usage based on its measured electricity consumption collected by smart meters. The perturbations provide a method to support Privacy Preserving Data Mining (PPDM) techniques. Evaluation of the performance results of the prototype applications illustrates the influence of the PPDM in improving the accuracy of said application.

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Hardware accelerator for data anonymization using dynamic partial reconfiguration

Sota Sawaguchi, Hiroaki Nishi

2016 IEEE International Conference on Smart Grid Communications, SmartGridComm 2016 （IEEE）     98 - 103 2016年12月

査読有り,  ISSN  2373-6836

　概要を見る

© 2016 IEEE. Smart City is a promising infrastructure for our near future community systems. It is predicted that more and more sensor devices and computing resources will be deployed in access networks because of the Internet of Things (IoT). This movement can create a wide variety of new applications with different requirements of delay, privacy and locality. Smart community dictates less than 10ms communication as a control interval in order not to disturb the lifeline systems, such as power supply. As such, future devices should have the following attributes: low-power, low-latency, and flexibility for various applications. In this paper, we propose an energy-aware, low-latency, and flexible local device, such as gateway or coordinator, which integrates an SoC FPGA with dynamic partial reconfiguration (DPR) feature to grapple with data anonymization. The data anonymization is important to protect private information in smart community because domestic human activities can be, for example, estimated by exploiting electric power consumption data, which is known as nonintrusive load monitoring (NILM). However, anonymization operations usually require processing cost at the order of O(n2) where n denotes the number of data in a privacy processing window. In case of encapsulating privacy information in a local network, privacy preserving computation should be achieved in a local device. Hence, we have implemented four primitive operations using DPR for various anonymization purposes. The proposed system achieves 18-328 times better performance and 10-200 times lower power consumption in every primitive anonymization method than Raspberry Pi 2 Model B.

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Introducing a Distance Vector Routing Protocol for ns-3 Simulator

Janaka Wijekoon, Rajitha Tennekoon, Erwin Harahap, and NISHI HIROAKI

Journal of EAI Endorsed Transactions on Mobile Communications and Applications （EAI）  2   79 - 87 2016年11月

共著,  ISSN  2032-9504

　概要を見る

Copyright © 2015 ICST. In network research, network simulators have been shown to be useful for testing and changing network protocols by means of a controlled manner. As an Internet systems simulator, ns-3 simulator provides an ideal simulation environment for network research. However, ns-3 is lack of table-driven IPv4 routing modules. Despite the fact that a routing protocol is a mandatory component of a network, it is necessary to introduce a table-driven routing protocol for the ns-3 which is able to maintain the network connectivity and consistency. To this end, we introduce a distance vector IPv4 wired routing protocol for the ns-3 simulator (DVRP). The proposing protocol is developed as a table-driven wired routing protocol. In this study, we describe the proposing routing protocol, including its design, implementation, behavior on networks, and limitations.

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Line replacement algorithm for L1-scale packet processing cache

Hayato Yamaki, Hiroaki Nishi

ACM International Conference Proceeding Series （ASSOC COMPUTING MACHINERY）  28-November-2016   12 - 17 2016年11月

査読有り

　概要を見る

© 2016 ACM. It will become a serious problem to increase power consumption of routers resulting from explosive increase of network traffics caused by IoT data, big data, and so on. Table lookups in packet processing are known as a bottleneck of the router from the points of both processing performance and power consumption. Packet Processing Cache (PPC), which accelerates the table lookups and reduces the power consumption of them by using cache mechanism, was proposed. However, it is difficult for PPC to obtain high cache hit rate because the size of PPC should be small, such as a L1 cache of processors, to get higher access speed. For this reason, an effective line replacement algorithm was considered in this study for reducing a cache miss without increasing the cache size. First, defects of applying typical line replacement algorithms to PPC were examined. Secondly, two algorithms, LRU Insertion Policy (LIP) and Elevator Cache (ELC), and improved algorithms of LIP and ELC called LIP1, LIP2, ELC1, and ELC2 were considered for improving the above defects. In simulation, it was shown Elevator Cache could reduce the cache miss by at most 17.4% compared with Least Recently Used, which applied to many cache systems.

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Sparse-coding-based household clustering for demand response services

Shintaro Ikeda, Hiroaki Nishi

IEEE International Symposium on Industrial Electronics （IEEE）  2016-November   744 - 749 2016年11月

ISSN  2163-5137

　概要を見る

© 2016 IEEE. For the development of a smart grid, smart meter is a key device to measure the electric power usage of network-connected houses. Smart meters are currently being installed into households, and play the important role for providing a demand response service. A demand response is a necessary service in order to adjust supply-demand balancing because the balance is kept by the cost in the electricity market. Therefore, the customers of the electricity supply companies are expected to be optimally assigned as a group. In this paper, we separate a set of households into clusters as optimally assigned customers. When conducting the clustering, the utilization of unsupervised learning using data from a smart meter is required. In this study, we propose a method of household clustering for a demand response event by sparse coding, which is a type of neural network. The proposed method generates a power consumption model of each household, finds simple relationship distances between households, and conducts hierarchical clustering based on these distances. In addition, to extract the characteristics of fluctuating load usage, we conduct data normalization that cuts off at a fixed load usage of each household. To confirm the effect of the proposed clustering method, the usage tendency of household air conditioning (A/C) units was evaluated.

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Estimation of Required EVs Battery Capacity for Leveling Demand Energy Considering Parking Durations

Tomoya Imanishi and NISHI HIROAKI

International Journal of Intelligent Transportation Systems Research, Online First Articles, Springer （Springer）  15 （ 3 ） 155 - 165 2016年07月

査読有り,  ISSN  1348-8503

　概要を見る

Vehicle-to-grid (V2G) is a key technology that is receiving significant attention as a method for achieving an efficient energy management system (EMS) by connecting electric vehicles (EVs) to an electric power grid. In this study, a fuzzy control method and an optimization control method were proposed as effective control methods for reducing the installation battery capacity and the electric charge in one day by leveling the electric load. As the result, the required battery capacity was 429 kWh for IEVBS model, and 480 kWh for MEVBS model using optimization control method. The control method could save at most $17.98 of an electric bill and achieve power leveling.

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High-speed decompression architecture of compressed HTTP streams for the internet routers

Hironori Okano, Hayato Yamaki, Hiroaki Nishi

2016 International Conference on FPGA Reconfiguration for General-Purpose Computing, FPGA4GPC 2016 （IEEE）     31 - 36 2016年07月

　概要を見る

© 2016 IEEE. In recent years, studies of DPI have been carried out actively. HTTP packets, which are a kind of DPI target, include GZIP compressed packets, and multi-streamed GZIP compressed HTTP cannot be analyzed directly on routers. Moreover, wire-rate processing is required to achieve on-router analysis. In this paper, HTTP decompressing architecture on routers supporting 40Gbps network is considered, and three mechanisms, which are parallelized architecture, cache architecture and piggy-back method, were proposed for achieving higher throughput. Hardware cost simulations by using Verilog HDL confirms it can achieve 10Gbps throughput at low circuit costs.

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The IOT mediated built environment: A brief survey

Jan Haase, Mahmoud Alahmad, Hiroaki Nishi, Joern Ploennigs, Kim Fung Tsang

IEEE International Conference on Industrial Informatics (INDIN) （IEEE）  0   1065 - 1068 2016年07月

ISSN  1935-4576

　概要を見る

© 2016 IEEE. The internet of things (IOT) continues to transform the world, and in many countries is now an integral part of our everyday lives-influencing everything from the way that we intercommunicate to how we conduct business. Innovators continue to find ways to integrate IOT into uses as far flung as fashion to medicine. This survey looks at how IOT is currently being integrated into the built environment for the purpose of saving energy and improving occupants' livelihoods. In particular, it reviews three technologies that have received a lot of attention in the literature as the future of an IOT mediated built environment. Based on this literature, predictions are made of the likely trends in regards to the future scholarship on these technologies.

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ECORS: Energy consumption-oriented route selection for wireless sensor network

Tadanori Matsui, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) （IEEE）  0   1044 - 1049 2016年07月

査読有り,  ISSN  1935-4576

　概要を見る

© 2016 IEEE. Automated metering infrastructure is employed widely in scientific fields as well as in industrial and commercial areas due to the development of wireless sensor network (WSN) technology. WSNs provide important features such as wireless multi-hop communication and they are easy to install everywhere; thus, extending the lifetime of WSNs is highly desirable. All WSN nodes consume a limited amount of energy from the battery during operations such as sensing, calculating, control, and communication and most of the power consumption is attributable to wireless communication. In this study, we propose energy consumption-oriented route selection (ECORS), which is a route selection algorithm that focuses on the remaining energy and energy consumption by WSN nodes. In ECORS, a sink node calculates all of the routes in the system by using the route lifetime (RL) as a metric according to the minimum residual energy (MRE) and the expected route cost (ERC). The route with the longest RL is selected by the proposed algorithm. By changing the route periodically using ECORS, the WSN system lasts 1.14 times longer as compared to that when the routes are fixed. We evaluated the performance of ECORS using an original WSN simulator. In realistic simulations, we measured the distance-packet error rate, current consumption, and discharge characteristic of a battery using actual sensor nodes assembled with an Arduino micro controller, XBee ZigBee wireless module, and lithium-polymer battery.

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Effective communicating optimization for V2G with electric bus

Toshichika Shiobara, Guillaume Habault, Jean Marie Bonnin, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) （IEEE）  0   992 - 997 2016年07月

ISSN  1935-4576

　概要を見る

© 2016 IEEE. The number of connected devices - also known as Internet of Things (IoT) - is exponentially increasing. Such sensors and devices also appear in transportation systems giving some intelligence to roads, equipment and vehicles. Nowadays, it is possible to communicate with the environment in order to have better everyday services. Furthermore, the number of registered - public or private - Electric Vehicle (EVs) is continuously increasing. These vehicles, equipped with large battery, need to be charged and so, have a significant impact on power grids. However, these EVs can also be seen as energy sources. It is therefore important to be able to plan both the charge and discharge of EVs. Including these vehicles into Vehicle-to-Grid technology is a way to efficiently manage such pools of batteries. But, as a consequence, grid requires to have almost real-time data on these vehicles and especially their battery status. This paper studies an optimized data aggregation method for a fleet of electric buses. Each bus provides different type of information with different priority level. The efficiency of the studied method was evaluated with a simulation platform developed with ns-3. Simulation results - based on real route and bus stop positions - show that an optimal buffer size has been found to both satisfy transmission delays and optimize communications.

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Prototype Implementation of Fast and Secure Traceability Service over Public Networks

R. Tennekoon, J. Wijekoon, E. Harahap and NISHI HIROAKI

IEEJ Transactions on Electrical and Electronic Engineering （WILEY）  11 （ S1 ） S122 - S133 2016年06月

査読有り,  ISSN  1931-4973

　概要を見る

© 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. Internet communication message protocol (ICMP)-based traceability methods are widely used to trace packets over the Internet; however, in their attacks, adversaries likewise use ICMP packets. Furthermore, the lack of security in ICMP-based traceability results in failures for many current traceability methods. Moreover, current routers are unable to provide extended services to Internet users and applications. To address this need, our laboratory has introduced the service-oriented router (SoR). SoR is middleware that can be implemented on a Cisco AXP and Juniper JunosV App Engine. In this paper, we propose a secure method of providing packet traceability over public networks using SoR features. We implemented a secure packet traceability service prototype on the ns-3 simulator. The test results conclude that there is a maximum additional cost of 48.69 and 123.91 μs of processing overhead per packet in each hop when the proposed secured traceability service is used with a 128-bit key space in AES-GCM and AES-CTR modes, respectively. Moreover, for 256-bit key spaces, AES-GCM and AES-CTR modes consumed additional 47.18 and 123.25 μs, respectively, over the plain traceability. Yet, from the evaluations on the test bed topology, it clearly shown that the proposed method was 79% faster than the conventional trace route method in providing the secured end-to-end traceability. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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How can a Service-oriented Router Merge with a CDN?

Janaka L. Wijekoon, Erwin H. Harahap, Rajitha L. Tennekoon and NISHI HIROAKI

IEEJ Transactions on Electronics, Information and Systems (C) （IEEJ）  136 （ 8 ） 1172 - 1179 2016年06月

査読有り,  ISSN  0385-4221

　概要を見る

© 2016 The Institute of Electrical Engineers of Japan. A large fraction of the Internet traffic is organized by the Content Delivery Networks (CDNs). CDNs redirect endusers to an appropriate server using Domain Name Servers (DNSs). Meanwhile, in future networks, it is anticipated that network routers will be equipped with more processing power and storage modules for providing most effective end-user services. From this viewpoint, a Service-oriented Router (SoR) is introduced to accelerate content-based services. This paper presents a novel method, DNS and SoR Collaborative Redirection (DSCR), to accelerate the end-user redirection. DSCR uses SoRs to collect and store network and server state information by placing SoRs at edges of the ISP network. The collected information is then used by the DSCR to leverage the DNS-based end-user redirection. We present the design and a prototype implementation of DSCR and, show how both SoR and DNS jointly can take advantage of existing Internet architecture to accelerate end-user redirection. We used a detailed simulation to evaluate the proposed method using various strategies. Simulations clearly demonstrate the effectiveness of the collaborative method, which yields 5-10% reduction in end-user latency when compared with DNS-based redirection.

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Implementation of Household’s Amenity Maintaining System Based on Behavior Estimation

Shoki Kawano, Tomoya Imanishi, Yasushi Ikedab, Hiroaki Nishi, Eiko Uchiyama

Procedia Environmental Science, Vol.34, pp.582-593, Improving Susteinability Concept in Developing Countries, ELSEVIER ScienceDirect （ELSEVIER ScienceDirect）  34   582 - 593 2016年04月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  1878-0296

　概要を見る

Research of residential EMS (Energy Management System) is mainly being promoted with a focus on energy saving initially. After that, it began to focus strikes the balance between the indoor comforts of the occupants and energy saving. Moreover, the control object is diversified in the home, there is a need for more detailed parameters of individuals to satisfy the comfort of the individual. This paper presents a novel method to estimate behaviours of the resident in a house. Also, it is to provide a comfortable environment at the same time energy saving by using the estimation results. (C) 2016 The Authors. Published by Elsevier B.V.

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A web platform for community-based adaptation decision

Yingjiu Bai, Ikuyo Kaneko, Hiroaki Nishi, Hidetaka Sasaki, Akihiko Murata, Kazuo Kurihara and Izuru Takayabu

The International Journal of Climate Change: Impacts and Responses （The Climate Change: Impacts & Responses Knowledge Community）  8 （ 2 ） 33 - 51 2016年01月

研究論文（学術雑誌）, 共著, 査読有り

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Implement domain name system (DNS) on network simulator-3: Implement RFC 1035 on ns-3

Janaka Wijekoon, Hiroaki Nishi

Proceedings of the 9th EAI International Conference on Simulation Tools and Techniques, SIMUTools 2016 （ACM）     56 - 65 2016年

　概要を見る

Copyright © 2016 EAI. This paper proposes to implement a domain name system (DNS) module to network simulator-3 (ns-3). The ns-3 is one of the well-known Internet simulators that provides the ideal simulation environment for network research. Despite its advantages, the ns-3 is not yet possesses a module to simulate DNS, which is an essential module required for Internet-oriented simulations. To this end, this paper implements a DNS module for ns-3 according to the design notes provided in RFC 1035. Moreover, this paper presents the implementation notes of the proposed ns-3 DNS module including its class structures, protocol message structures, name server application development, and host-to-IP resolver development. The proposed ns-3 DNS module is evaluated in terms of host-to-IP mapping, recursive DNS resolution, DNS cache management, and internationalized domain name support.

Panel Discussions "Computing and Communication Evolution for IoT Innovations"

Hiroaki Nishi, Jiang Xu, Luca Benini, Michael McCool, Toshitsugu Sakamoto, Shingo Fujimoto

2016 IEEE SYMPOSIUM IN LOW-POWER AND HIGH-SPEED CHIPS (COOL CHIPS XIX) （IEEE）     1 - 2 2016年

ISSN  2473-4683

　概要を見る

"Internet of Things" connects everything to provide new services. These new services confront severe requirements represented by the fact that systems handle the real world. Moreover, ubiquitous IoT devices generate a tremendous amount of data. This data concentration also makes it difficult to accomplish the requirements. Thus, future computing and communication systems have to face this difficulty. Now, computing and communication evolution is truly desired. This panel session discusses what kinds of computing and communication evolution are desired and expected and how to achieve them.

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Hyperthermic effects of hand bathing: benefits of incorporating finger flexion-extension exercise

Tadasu Ohshige, Akihiko Ohwatashi, Ryoji Kiyama, Hiroaki Nishi, Akihisa Takamori

JOURNAL OF PHYSICAL THERAPY SCIENCE （SOC PHYSICAL THERAPY SCIENCE）  27 （ 12 ） 3779 - 3782 2015年12月

ISSN  0915-5287

　概要を見る

[Purpose] The purpose of our study was to compare the effects of hand bathing using plain water and water supplemented with inorganic salt and carbonated gas and to assess the hyperthermic effects of performing finger flexion-extension exercise while bathing in water with carbonated gas and inorganic salt and without water. [Subjects and Methods] Sixteen healthy, young males were subjected to plain water bathing, CO2 bathing, kineto-CO2 bathing, or no bathing. CO2 bathing involved bathing in a solution of artificial bath additives including inorganic salts and carbon dioxide. Partial bathing of the hand was implemented for 20 minutes at 41 degrees C. The concentration of carbonic gas was set at 33 ppm. In the kineto-CO2 bathing condition, finger flexion-extension exercise was performed at 60 laps per minute in the same solution used in CO2 bathing. The control group engaged in the same exercise as those in the kineto-CO2 bathing group, but without bathing. [Results] A significant increase in deep-body temperature was observed in the CO2 bathing and kineto-CO2 bathing conditions compared with both the plain water bathing and control condition. [Conclusion] Significantly heightened hyperthermic effects were observed when finger flexion-extension exercise was performed during CO2 bathing.

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SLRouting: Server link router state routing protocol design and implementation

Janaka L. Wijekoon, Hiroaki Nishi

Asian Internet Engineering Conference, AINTEC 2015 （Association for Computing Machinery, Inc）     1 - 8 2015年11月

査読有り

　概要を見る

© 2015 ACM. Packet propagation delay reduction is becoming the primary concern of the Internet. Internet service providers (ISPs) attempt to optimize packet routing to offer the best route to their subscribers by achieving desired network performance. Consequently, a route computation metric that uses packet propagation delay instead of link state will be a strong incentive for ISP routing optimization, in which case ISPs could ensure minimal delay route paths for their subscribers. To this end, we present SLRouting, a novel Interior Gateway Routing Protocol. SLRouting calculates a composite route metric using packet waiting delays of servers and routers as well as the packet propagation delay of network links. SLRouting computes the route matrix by selecting the minimal delay path for destination networks. This paper presents the first version of the SLRouting including its theory, design, and implementation notes. A prototype of the proposed protocol is implemented using the ns-3 simulator, and the results were used to evaluate the proposed protocol.

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HVAC energy saving: considering individual thermal comfort

Mio Fukuta and Hiroaki Nishi

IFHE DIGEST 2016 （IFHE）  J98-B （ 10 ） 27 - 29 2015年10月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  2401-3912

インターネットルータにおけるHTTP圧縮ストリームの高速展開処理機構の提案

八巻　隼人, 中村　優一, 高際　兼一, 松井　加奈絵, 西　宏章

電子情報通信学会論文誌 （電子情報通信学会）  J98-B （ 10 ） 1104 - 1114 2015年10月

研究論文（学術雑誌）, 共著, 査読有り

Time Synchronization Technique Using EPON for Next-Generation Power Grids

Yuichi Nakamura, Andy Harvath and Hiroaki Nishi

IEICE TRANSACTIONS on Communications （IEICE）  E99-B （ 4 ） 859 - 866 2015年10月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  0916-8516

　概要を見る

Copyright © 2016 The Institute of Electronics, Information and Communication Engineers. Changing attitudes toward energy security and energy conservation have led to the introduction of distributed power systems such as photovoltaic, gas-cogeneration, biomass, water, and wind power generators. The mass installation of distributed energy generators often causes instability in the voltage and frequency of the power grid. Moreover, the power quality of distributed power grids can become degraded when system faults or the activation of highly loaded machines cause rapid changes in power load. To avoid such problems and maintain an acceptable power quality, it is important to detect the source of these rapid changes. To address these issues, next-generation power grids that can detect the fault location have been proposed. Fault location demands accurate time synchronization. Conventional techniques use the Global Positioning System (GPS) and/or IEEE 1588v2 for time synchronization. However, both methods have drawbacks-GPS cannot be used in indoor situations, and the installation cost of IEEE 1588v2 devices is high. In this paper, a time synchronization technique using the broadcast function of an Ethernet Passive Optical Network (EPON) system is proposed. Experiments show that the proposed technique is low-cost and useful for smart grid applications that use time synchronization in EPON-based next-generation power grids.

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Privacy-preserving data collection for demand response using self-organizing map

Kengo Okada, Kanae Matsui, Jan Haase, Hiroaki Nishi

Proceeding - 2015 IEEE International Conference on Industrial Informatics, INDIN 2015 （IEEE）     652 - 657 2015年09月

査読有り,  ISSN  1935-4576

　概要を見る

© 2015 IEEE. Homomorphic encryption for smart grids has been investigated in many studies. It is possible to estimate the total power consumption in an area without knowing the consumption data of individual households. In the case of demand response (DR), it is important to calculate the total electric power consumption in an area because DR reports are published accordingly to reduce peak power consumption when the demand is high. However, the published data may reveal private information about residents, such as the timings of specific activities (leaving from and returning home), and device details. To overcome this problem, we propose a method specialized to enable energy providers to securely share electric power consumption data. The proposed method uses a self-organizing map (SOM), which is an unsupervised learning method. In order to share power consumption data while preserving privacy, the SOM is shared without the raw data. In this framework, a target accuracy of nearly 3% is achieved, while actual data are not published by any company.

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Proposal for home energy management system to survey individual thermal comfort range for HVAC control with little contribution from users

Mio Fukuta, Kanae Matsui, Minako Ito, Hiroaki Nishi

Proceeding - 2015 IEEE International Conference on Industrial Informatics, INDIN 2015 （IEEE）     658 - 663 2015年09月

査読有り,  ISSN  1935-4576

　概要を見る

© 2015 IEEE. Heating, ventilation, and air conditioning (HVAC) control is used to effectively reduce energy consumption in a home energy management system (HEMS). For the HVAC control, it is necessary to evaluate the indoor comfort level because the HVAC operation is significantly related to indoor environmental conditions. Although there are some indices for indoor comfort, individuals have different comfort ranges. A questionnaire is one way to gather data on individual comfort ranges. However, it requires contributions from users. Therefore, we proposed a new survey method that varied the intervals of the questions addressed to users to reduce the number of responses needed. Additionally, a comfort estimation method was proposed that did not require a questionnaire. This method analyzes the user's operation of the HVAC system, such as touching its on/off switch. An HEMS with the capability of utilizing these two methods was installed in a laboratory and 16 houses in Miyagi prefecture, Japan. An experiment using this HEMS was conducted, and it was able to reduce the number of feedbacks needed to maintain each person's comfort by an average of 32.2%. The HEMS provided the same accuracy as hourly questionnaires. Namely, it confirmed that the estimation based on the air conditioner operations was almost the same as that based on an hourly questionnaire.

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Effectiveness of a Service-oriented Router in Future Content Delivery Networks

Janaka Wijekoon, Erwin Harahap, Kenichi Takagiwa, Rajitha Tennekoon, Hiroaki Nishi

International Conference on Ubiquitous and Future Networks, ICUFN （IEEE）  2015-August   444 - 449 2015年08月

査読有り,  ISSN  2165-8528

　概要を見る

© 2015 IEEE. Content Delivery Networks (CDNs) constitute a major portion of Internet traffic. To cope with increasing demand for content, CDNs have deployed distributed infrastructures on Internet Service Providers (ISPs') networks. Most CDN systems optimize their traffic flow using Domain Name Systems. However, they do not collaborate with the ISPs, and the lack of collaboration limits performance such as end-user latency. Meanwhile, in future networks, it is anticipated that network routers will be equipped with more processing power and storage modules for providing most effective end-user services. From this viewpoint, a Service-oriented Router (SoR) is introduced to accelerate content-based services. In this paper, the benefits of introducing an SoR to an ISP network for maintaining ISP-CDN collaboration is outlined. Furthermore, a prototype design of the proposed system is presented. Simulations clearly demonstrate the effectiveness of the proposed ISP-CDN collaboration, which yields a 30-50% reduction in end-user latency.

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Disaggregation of Electric Appliance's Consumption Using Collected Data by Smart Metering System

Kanae Matsui, Yoshiki Yamagata, Hiroaki Nishi

ELSEVIER Energy Procedia （ELSEVIER）  75   2940 - 2945 2015年08月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  1876-6102

　概要を見る

© 2015 The Authors. Published by Elsevier Ltd. In order to enhance electricity conservation in households, detecting which electric appliances consume high electricity is effective. However, collecting every data of electric appliances needs many devices and it would be high costs. Therefore, data disaggregation from total data to each appliance leads to the reduction of cost and electricity. This paper presents how to disaggregate the consumption of electric appliances from total electricity consumption. In order to disaggregate electricity consumption of electric appliances from total energy consumption, sparse coding has been implemented. However, changes in the use of electric appliances are difficult to express in this method. Therefore, we propose a novel sparse coding method, named, "0-1 sparse coding" to disaggregate which electric appliances were used in the total consumption of electricity. In order to collected sample data for analyzing the methods, we installed smart metering systems in two households. The system collects the data of total electricity consumption and data in the main electric appliances in every 5-minutes. We evaluate two methods, 1) our proposed method, and 2) discriminative sparse coding method. From the results, our proposed method increased the accuracy about 44.8% than the previous method.

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学習効率を考慮したキャンパスエネルギーマネジメントシステムの提案と実証

今西　智哉，松井　加奈絵，西　宏章

計測自動制御学会論文集, SICETR-D-14-00141 （公益社団法人 計測自動制御学会）  51 （ 5 ） 344 - 351 2015年05月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  0453-4654

　概要を見る

Many studies dealing with energy saving have been conducted from the viewpoint of mitigating global warming. However, most of them only consider energy saving and ignore total environmental impact toward human life. It is necessary to provide a comfortable workspace using efficient and optimized energy control, because excessive demand control may have a negative impact on a living environment. Excessive demand control also brings impact on efficiency of working and learning. In order to provide a comfortable indoor environment, some environmental indexes are necessary, including not only temperature, humidity, luminance, wind speed, but also CO₂ concentration. In this paper, we propose a novel method to allocate power optimally by using learning efficiency, which contains both PMV and CO₂ concentration as its index. We constructed experiments at real place with developed BEMS that enables both monitoring environmental indexes and controlling HVAC systems.

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スマートコミュニティにおけるインフラストラクチャとサービス (小特集 最新の情報通信技術から見たインフラ統合社会と今後の展開 : スマートコミュニティ実現のためのインフラはどうあるべきか)

西 宏章

電子情報通信学会誌 = The journal of the Institute of Electronics, Information and Communication Engineers （一般社団法人電子情報通信学会）  98 （ 2 ） 112 - 117 2015年02月

ISSN  0913-5693

　概要を見る

様々なインフラに情報通信技術を投入しつつ融合させたスマートコミュニティにおいては,スマートメータによる電力利用情報や,家庭向けエネルギー管理システムによる環境,生活情報,利用者の行動情報,気象情報,医療情報など,様々な情報が取得,活用される.これらを横断的に解析して新しい知見を入手,提供することや,本来の目的とは異なる目的で利用するなど,新しいサービスの展開が期待されている.本稿では,スマートコミュニティ向けサービスを構築する上で必要となる,プライバシー問題の解決といった情報の扱い方,必要となるインフラ,具体的なサービス事例について解説する.

Active controlled shutter for effective cooling of servers in data center

Tomomichi Noguchi, Hiroaki Nishi

IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society （IEEE）     1668 - 1673 2015年

ISSN  1553-572X

　概要を見る

© 2015 IEEE. In a data center, the main challenge is dealing with the power consumption of IT equipment and air conditioning (AC) units. To reduce the total energy in a data center, many techniques and approaches have been proposed. These strategies focused on the idle power of servers or controlling AC units while considering the temperature of server racks independently. In this paper, an active controlled shutter that enables the control of cooling airflow was proposed while considering the temperature of servers independently. By using the proposed method, wasted cooling energy could be eliminated. In a simulation of the proposed method, a conventional task assignment method was used, and start-up delays were considered. Additionally, the effect of the active controlled shutter was evaluated. The shutter blocks off cool air from cold aisles by observing the temperature of a server. As a result, the cooling power of the AC can be reduced by preventing the excessive cooling of idle or shut-down servers. An experimental result shows that the proposed method reduced the cooling energy by 22.8 %.

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Air conditioning control using self-powered sensor considering comfort level and occupant location

Sachio Godo, Jan Haase, Hiroaki Nishi

IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society （IEEE）     2497 - 2502 2015年

ISSN  1553-572X

　概要を見る

© 2015 IEEE. In this paper, an effective low-cost heating, ventilation, and air conditioning (HVAC) control system incorporating a new sensor is proposed. This research builds upon our previous system, which achieved efficient control of the air conditioning (AC) for a large room in a library. By detecting whether or not individual chairs were occupied and regulating the AC near unoccupied chairs, the system reduced the overall power consumption. This detection was achieved using pressure sensors installed in the chairs. However, the sensors required battery power to measure voltage and transmit data. The batteries needed to be replaced within several months, and thus the system required frequent maintenance. In this paper, we introduce a self-powered sensor. The sensor integrates an energy-harvesting switch and a wireless transmitter. The action of pressing or releasing the switch generates sufficient electricity to power the device, and this enables long-term operation without replacing or charging the batteries. When these sensors are integrated into chairs, occupancy status can be detected without additional power or regular maintenance. The proposed improved system with battery-free chair sensors is evaluated in an eight-day experiment conducted at a library in Kurihara, Miyagi Prefecture, Japan. The energy efficiency evaluation indicates that the proposed system can reduce electricity consumption by 18.3%. The predicted mean vote (PMV) values for the environment in the library are determined to assess the comfort level, and these values confirm that the proposed system is capable of maintaining occupant comfort. In the experiment, wireless sensor network is built through the Library to the Laboratory. All sensing data (e.g. temperature, humidity occupancy, status, power consumption, air conditioning status) are managed on the Cloud.

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Effective metering data aggregation for smart grid communication infrastructure

Toshichika Shiobara, Peter Palensky, Hiroaki Nishi

IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society （IEEE）     2136 - 2141 2015年

査読有り,  ISSN  1553-572X

　概要を見る

© 2015 IEEE. Advanced metering infrastructure (AMI) systems have been developed to perform automated meter reading, reduce peak loads, and use energy efficiently. Two issues exist regarding this system. The first issue is the communication and handling of consumer data concerning electricity collected by power utilities. The second issue is the management of communication network resources and scheduling of metering to avoid congestions and communication errors. The major device for addressing these two issues is a concentrator that acts as a data relay point in an AMI system. The concentrator collects data from the meter and sends them through communication networks. This study discusses the aggregation methods of the concentrator with respect to the aforementioned two issues and proposes a method to reduce network utilization and message size on a server. The method concatenates small smart metering messages sent from relevant meters. The traditional method aggregates and concatenates messages without numerical processing. The proposed method processes messages at the concentrator to reduce total message size and calculation cost on the server. Moreover, the method that combines the traditional and proposed methods was evaluated by considering a real-world case. These methods were simulated by using an ns-3 network simulator to evaluate their efficiency in sending messages concerning the volume of power consumption to the server. The results of the simulations show that the proposed methods reduce message size by as much as 98.5% in some cases and, by means of the concentrator, shorten the communication time between meters and the server. The proposed method can help to reduce loads on networks and servers.

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Implementation and evaluation of HEMS management middleware using XML

Yuta Emura, Toshichika Shiobara, Tomomichi Noguchi, Hiroaki Nishi

IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society （IEEE）     2148 - 2153 2015年

査読有り,  ISSN  1553-572X

　概要を見る

© 2015 IEEE. Recently, efficient energy management systems have been in high demand to reduce overall energy consumption. In particular, energy consumption in the civilian sector is increasing considerably. Therefore, the effective use of energy in this sector should be emphasized. To do so, the introduction of a Home Energy Management System (HEMS) is effective because such systems allow households to control power consumption, generation, and charging. HEMSs are designed to provide services that are appropriate from the perspective of the user. However, in order to control a variety of consumer electronics devices, existing middleware does not consider descriptive and operational abilities when designing HEMS applications. In this paper, we propose an HEMS control mechanism that uses a combination of control statements written in Extensive Markup Language. These control statements, or «HEMS modules,» comprise three types: Trigger, Condition, and Event. The modules can connect with each other to express event transitions. The proposed middleware facilitates the description and control of HEMS devices for users. The proposed middleware was implemented in an embedded HEMS controller and evaluated in a real household environment.

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Enhanced building thermal model by using CO2 based occupancy data

Tomoya Imanishi, Rajitha Tennekoon, Peter Palensky, Hiroaki Nishi

IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society （IEEE）     3116 - 3121 2015年

査読有り,  ISSN  1553-572X

　概要を見る

© 2015 IEEE. Prevailing low energy buildings attracts lots of attention in the world. Many studies have contributed in introducing higher thermal efficiency towards rooms with low energy heating, ventilation, and air-conditioning (HVAC) systems. However, current HVAC systems do not consider CO2 concentration change and thermal contribution towards human bodies in a room. This paper presents a novel method to predict thermal dynamics, including person count. Occupancy data are dynamically estimated by CO2 concentration and thermal contribution from the human bodies. The model is formulated as a resistor-capacitor circuit (RC circuit) in the Modelica modeling language. All parameters in a simulation are identified using actual building data during the winter season in Japan. Results are validated using measured information of actual building environment, and the test results concluded an improvement of absolute percentage error by 0.16 % over the conventional model. From the test results, it was concluded that the moving average filter of 20 minutes was an appropriate mean time to represent the time delay value.

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RAM-based hardware accelerator for network data anonymization

Fumito Yamaguchi, Kanae Matsui, Hiroaki Nishi

Conference Digest - 24th International Conference on Field Programmable Logic and Applications, FPL 2014 （Institute of Electrical and Electronics Engineers Inc.）     1 - 4 2014年10月

査読有り

　概要を見る

© 2014 Technical University of Munich (TUM). Many network services including intrusion detection and recommendation provide their services by analyzing information acquired from network transactions. A careful analysis of these data can reveal valuable information when deep packet inspection is performed. Since these packet analyses generate sensitive information from enormous volumes of transmitted data, the requirement for data anonymization has been discussed. There have been many studies of anonymization techniques and their implementation in software applications. However, limited research has been undertaken regarding hardware-based anonymizers. This paper proposes and evaluates a RAM-based anonymization architecture that maintains both high throughput and a low information-loss ratio.

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Electrified Vehicles and the Smart Grid: the ITS Perspective

X. Cheng, X. Hu, I. Husain, K. Inoue, P. Krein, R. Lefevre, Y. Li, H. Nishi, J. Taiber, F. Wang, L. Yang, Y. Cha, W. Gao, and Z. Li

IEEE Transactions on Intelligent Transportation Systems 15 （ 4 ） 1388 - 1404 2014年08月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  1524-9050

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Electrified Vehicles and the Smart Grid: the ITS Perspective

X. Cheng, X. Hu, I. Husain, K. Inoue, P. Krein, R. Lefevre, Y. Li, H. Nishi, J. Taiber, F. Wang, L. Yang, Y. Cha, W. Gao, and Z. Li

IEEE Transactions on Intelligent Transportation Systems 15 （ 4 ） 1388 - 1404 2014年08月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  1524-9050

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High-throughput and low-cost hardware accelerator for privacy preserving publishing

Fumito Yamaguchi, Hiroaki Nishi

Proceedings - 2014 IEEE 22nd International Symposium on Field-Programmable Custom Computing Machines, FCCM 2014 （IEEE）     242 - 242 2014年07月

査読有り

　概要を見る

© 2014 IEEE. Deep Packet Inspection (DPI) has become crucial for providing rich internet services, such as intrusion and phishing protection, but the use of DPI raises concerns for protecting the privacy of internet users. In this paper, a RAM-based hardware anonymizer is proposed for implementation on a Virtex-5 FPGA device. The results of the hardware anonymizer showed that the proposed architecture reduced circuit usage by 40%.

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Router-based Content Aware Data Redirection for Future CDN Systems

Janaka Wijekoon, Shinichi Ishida, Erwin Harahap, Rajitha Tennekoon and, Hiroaki Nishi

International Journal of Computer Network and Information Security (IJCNIS) （MECS Publisher）  6 （ 7 ）  2014年06月

共著, 査読有り,  ISSN  2074-9090

快適性指標におけるばらつきを考慮した効率のよい家電制御システム

伊東 未奈子, 西 宏章

計測自動制御学会論文集, SICETR-D-14-00001R1 （測自動制御学）  50 （ 6 ） 471 - 477 2014年06月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  0453-4654

　概要を見る

Maintaining indoor condition is an important factor for controlling electric appliances in living space. Generally speaking, a sense of feeling indoor condition is variable between residents. The conventional methods were dealing with this by supposing general residential. This means the conventional methods cannot consider all the residents. This is not realistic when considering installation of the system into the real environment. Thus, in this study, the Bayes' estimation was utilized to analyze the amenity variability. As a result of analysis, the new index, satisfaction rating index, was proposed. To achieve this, the HEMS was constructed in the actual operating residence. As a result, the analysis was acquired from 14 people from 3 different residences. To confirm the availability of the proposed index, the home appliance control system utilizing satisfaction rating index was conducted. The proposed system was evaluated by the experiment in the actual operating residence. From the result, the evaluation showed the availability of the proposed system and satisfaction rating index.

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Previous hop data retransmission service for SoR-based public networks

Rajitha Tennekoon, Janaka Wijekoon, Erwin Harahap, Hiroaki Nishi

2014 7th International Conference on Information and Automation for Sustainability: "Sharpening the Future with Sustainable Technology", ICIAfS 2014 （IEEE）  2014年03月

査読有り,  ISSN  2151-1802

　概要を見る

© 2014 IEEE. It is a well-known fact that the Internet traffic travels through public networks and these networks are vulnerable and congested. Whenever an error in a packet is detected, the packet should be retransmitted back to the receiver to reduce/overcome the data loss. Automatic repeat request (ARQ) method is a well-known data retransmission method used by protocols such as Transmission Control Protocol (TCP). This method will retransmit data all the way from the sender resulting higher end-to-end retransmission delays in the packet transmission. Nevertheless this method is widely used and operational, it will also introduce unnecessarily duplicate packets further congesting the networks when it retransmit the entire packet stream from an unacknowledged packet after detecting a retransmission requirement. Encryption and public key cryptography are important technologies that are used to preserve data security and integrity, and to reduce information theft on the public networks. These existing technologies have less flexibility over the current security requirements and the conventional routers are unable to provide end services to the users and applications. To address this need, our laboratory introduced the per-hop data encryption protocol for service-oriented router (SoR) based public networks which allows more secured and flexible method to transfer data over public networks [15]. SoRs are introduced to maintain rich information for the next-generation networks by shifting the current Internet infrastructure to an information-based and an open-innovation platform [6]. SoR is a middleware and can be implemented on a Cisco AXP and Juniper JunosV App Engine where it can analyse all packet stream transactions on its interfaces. Using the features of the SoR, in this paper, we propose a previous hop data retransmission service for public networks. This proposing service can provide higher data availability and reliability to the data that traverses through public networks, reducing the end-to-end data retransmission delays. We implemented a prototype of previous hop data retransmission service on the ns-3 simulator. Furthermore, from the evaluations on the test bed topology, it clearly showed that the proposed method was 80.43% faster than the conventional ARQ based retransmission method.

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Construction of HEMS in Japanese cold district for reduction of carbon dioxide emissions

Mio Fukuta, Minako Ito, Fumito Yamaguchi, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     5338 - 5343 2014年02月

査読有り,  ISSN  1553-572X

　概要を見る

© 2014 IEEE. Increasing carbon dioxide emissions have given rise to global warming. Therefore, the need to reduce these emissions is being widely discussed. Decreasing energy consumption by efficient energy use is required to directly influence carbon dioxide emissions. Recently, energy consumption in the civilian sector is rising in Japan. To address this problem, the introduction of a Home Energy Management System (HEMS) is effective because it enables the control of power consumption and an economical energy use. Controlled heating, ventilation, and air conditioning (HVAC) is an essential function to be implemented in HEMS. HVAC control systems are now commercial and several HEMS experiments with HVAC control have been conducted in Japan. However, only few experiments have been conducted in cold districts because peak energy consumption predominantly occurs in summer. Nevertheless, from a carbon dioxide emissions reduction viewpoint, in such districts, the use of kerosene fan heaters, which are popular, becomes a dominant source of emissions around the year, but particularly in winter. In this study, we constructed a HEMS at 16 houses in a cold district, with the collecting function of environmental conditions, heating appliances status, the amount electric/oil energy consumption, and with the control function of HVAC systems. In particular, specially designed fully-controlled and monitored kerosene fan heaters are introduced. To confirm the effectiveness of the proposed HEMS, an energy saving experiment was conducted in which the use of kerosene fan heaters was controlled on the basis of the acquired environmental information, without degrading the room comfort. A reduction in carbon dioxide emissions was monitored along with the comfort level. This is the first experiment which integrates kerosene fan heaters into HEMS. This study demonstrated the ability of autonomous heater control to reduce the burden of residents and the usefulness of HEMS in Japan's cold district.

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Cost-effective air conditioning control considering comfort level and user location

Sachio Godo, Kanae Matsui, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     5344 - 5349 2014年02月

査読有り,  ISSN  1553-572X

　概要を見る

© 2014 IEEE. Heating, ventilation, and air conditioning (HVAC) are important factors for a building energy management system (BEMS). Efficient control of the air conditioning (AC) is required to maintain both energy efficiency and human comfort. However, AC control systems are expensive to install in buildings. In this study, a cost-effective AC control system intended for a library is proposed; it is also applicable to other facilities such as offices and meeting spaces. This system uses seating sensors for maintaining both energy efficiency and human comfort. Conventional AC control systems generally use expensive motion sensors or vision sensors as well as temperature and humidity sensors to acquire information on both the location and the comfort of users and to provide location-based control to users. In order to reduce sensor-based cost, the proposed system uses low-cost pressure sensors and maintains both energy efficiency and the comfort level. For detecting seat occupancy and locations, low-cost pressure sensors and low-power communication nodes are attached to chairs and they transmit seating data to the database of a server. A programmable logic controller is used to control the proposed AC system according to the information stored in the database. The system is evaluated using a 10-day experiment conducted at a library in Kurihara City in Miyagi prefecture of Japan. The results of energy efficiency evaluation in this experiment show that the proposed system can reduce electricity consumption by 18.3%. Through measurement of the predicted mean vote values of users of the library, the proposed system is found to be capable of maintaining user comfort.

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A router-based management system for prediction of network congestion

Erwin Harahap, Janaka Wijekoon, Rajitha Tennekoon, Fumito Yamaguchi, Shinichi Ishida, Hiroaki Nishi

International Workshop on Advanced Motion Control, AMC （IEEE）     398 - 403 2014年

査読有り,  ISSN  1943-6572

　概要を見る

Network Management System (NMS) plays an important role in networks to maintain the best performance of a network. It employs variety of tools, applications, and devices in order to support network administrators to monitor and maintain the stability of a network. Fault management is part where the NMS dealing with problems and failures, such as congestion, in the network. Generally, most NMSs use Simple Network Management Protocol (SNMP) to monitor and map network availability, performance, and error rates. In the existing NMS process, an SNMP agent is deployed to get information about the network condition and then send them to the administrator for taking further action on solving the problems. However, deploying such agent to the network may increase the traffic density. On the other hand, packet latency and RTT will increase as well. In this paper, we implemented a prototype of the proposing novel system that no need to deploy such agent to obtain network information. Our system analyze the streaming traffic by implementing a Service-oriented Router (SoR). Our objective is to predict a congestion in the specific link in the network through a router-based data traffic analysis using a Bayesian network model. The purpose of the prediction is to support the network administrator to notify the early warning regarding to the fault in the network as long as possible before it actually happening. By this prediction, the network administrator can immediately taking action to avoid the problems.We provided simulation experiment to demonstrate the performance of the proposed system. Our simulation results show that the proposed system can predict a congestion link caused by a particular problem, before hand it is getting congested. © 2014 IEEE.

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Per hop data encryption protocol for transmission of motion control data over public networks

Rajitha Tennekoon, Janaka Wijekoon, Erwin Harahap, Hiroaki Nishi, Eiichi Saito, Seiichiro Katsura

International Workshop on Advanced Motion Control, AMC （IEEE）     128 - 133 2014年

査読有り,  ISSN  1943-6572

　概要を見る

Bilateral controllers are widely used vital technology to perform remote operations and telesurgeries. The nature of the bilateral controller enables control objects, which are geographically far from the operation location. Therefore, the control data has to travel through public networks. As a result, to maintain the effectiveness and the consistency of applications such as teleoperations and telesurgeries, faster data delivery and data integrity are essential. The Service-oriented Router (SoR) was introduced to maintain the rich information on the Internet and to achieve maximum benefit from networks. In particular, the security, privacy and integrity of bilateral communication are not discoursed in spite of its significance brought by its underlying skill information or personal vital information. An SoR can analyze all packet or network stream transactions on its interfaces and store them in high throughput databases. In this paper, we introduce a hop-by-hop routing protocol which provides hop-by-hop data encryption using functions of the SoR. This infrastructure can provide security, privacy and integrity by using these functions. Furthermore, we present the implementations of proposed system in the ns-3 simulator and the test result shows that in a given scenario, the protocol only takes a processing delay of 46. 32 μs for the encryption and decryption processes per a packet. © 2014 IEEE.

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Per-hop data encryption protocol for transmitting data securely over public networks

Rajitha Tennekoon, Janaka Wijekoon, Erwin Harahap, Hiroaki Nishi

Procedia Computer Science （ELSEVIER SCIENCE BV）  32   965 - 972 2014年

査読有り,  ISSN  1877-0509

　概要を見る

It is a well-known fact that the Internet traffic travels through public networks. These networks lack security and are vulnerable. Encryption and public key cryptography are important technologies that are used to preserve data security and integrity, and to reduce information theft on the public networks. However, the existing routing protocols are incapable of providing secure data transmission on public networks. To this end, our laboratory introduced the Service-oriented Router (SoR) to maintain rich information for the next-generation networks by shifting the current Internet infrastructure to an information-based and an open-innovation platform. An SoR can analyze all packet stream transactions on its interfaces and store them in high throughput databases. Using the features of the SoR, in this paper, we propose a hop-by-hop routing protocol that provides per-hop data encryption. This infrastructure is proposing to preserve both the security and the privacy of data that traverses through public networks. We implemented a prototype of per-hop data encryption protocol on the ns-3 simulator and the results obtained are discussed in this paper. © 2014 Published by Elsevier B.V.

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DC-Balanced Perfect Classified Channel for Hiding Farming Signal

西 宏章

IEEJ Transactions on Electronic Engineering （The Institute of Electrical Engineers of Japan）  8 （ 6 ） 610 - 615 2013年11月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  1931-4973

　概要を見る

Perfect classified channel (PCC) was proposed as a hardware-based Layer-1 encryption system that prevents of leakage of packet information and any indication of the existence of packets. PCC can provide high-throughput communication, which is encrypted using AES encryption hardware, while maintaining DC balancing, which is generally managed using the 8B/10B or 64B/66B coding algorithms. In this paper, we propose two methods to classify a framing signal that indicates a boundary between packets, for PCC. These methods facilitate an improved level of security compared with existing communication channels and make PCC more secure. This paper describes the details of the PCC architecture including the hardware costs while also verifying the DC-balance performance of PCC and the confidentiality of framing signals. © 2013 Institute of Electrical Engineers of Japan.

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HEMS環境におけるスマートフォンを用いた活動量の推定と空調制御への利用

伊東 未奈子, 西 宏章

組込みシステムシンポジウム2013論文集 （IEEE）  2013 （ 2013 ） 140 - 146 2013年10月

ISSN  1553-572X

　概要を見る

As a peak-cut or peak leveling control, heating, ventilation, and air conditioning (HVAC) are essential method for controlling the demand of electric power consumption. However, it is important to consider environmental amenity when designing control systems because the control may cause the deterioration of the amenity. In existing methods, metabolic equivalent (MET) values are not considered. Measurement and processing of MET values can be costly, requiring special infrastructure to both measure the values and communicate these values with a home energy management system (HEMS) or building energy management system (BEMS). This paper proposes a HVAC control method that considers the tradeoff between environmental amenity and energy conservation using the Keio University network oriented intelligent and versatile energy management system (KNIVES). The proposed method uses an iPod touch or iPhone application to obtain accurate measurements of both the MET value and the predicted mean vote (PMV). The accuracy of the PMV values after incorporation of MET estimates was confirmed experimentally. A HEMS experiment was conducted and a reduction in energy consumption was observed, demonstrating the usefulness of both the application and the proposed HVAC control method.

Modeling of Router-based Request Redirection for Content Distribution Network

Erwin Harahap, Janaka Wijekoon, Rajitha Tennekoon, Fumito Yamaguchi, Shinichi Ishida, an, Hiroaki Nishi

International Journal of Computer Applications 76 （ 13 ） 37 - 46 2013年08月

研究論文（学術雑誌）, 共著, 査読有り

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An Improved Cache Mechanism for Cache-based Network Processor

Hayato Yamaki a, Hiroaki Nishi

Journal of Communication and Computer 3   277 - 286 2013年03月

研究論文（学術雑誌）, 共著, 査読有り

A practical case study of HVAC control with MET measuring in HEMS environment

Minako Ito, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     8136 - 8141 2013年

　概要を見る

As a peak-cut or peak leveling control, heating, ventilation, and air conditioning (HVAC) are essential method for controlling the demand of electric power consumption. However, it is important to consider environmental amenity when designing control systems because the control may cause the deterioration of the amenity. In existing methods, metabolic equivalent (MET) values are not considered. Measurement and processing of MET values can be costly, requiring special infrastructure to both measure the values and communicate these values with a home energy management system (HEMS) or building energy management system (BEMS). This paper proposes a HVAC control method that considers the tradeoff between environmental amenity and energy conservation using the Keio University network oriented intelligent and versatile energy management system (KNIVES). The proposed method uses an iPod touch or iPhone application to obtain accurate measurements of both the MET value and the predicted mean vote (PMV). The accuracy of the PMV values after incorporation of MET estimates was confirmed experimentally. A HEMS experiment was conducted and a reduction in energy consumption was observed, demonstrating the usefulness of both the application and the proposed HVAC control method. © 2013 IEEE.

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Distributed algorithm for router-based management of replica server in next-CDN infrastructure

Erwin Harahap, Janaka Wijekoon, Rajitha Tennekoon, Fumito Yamaguchi, Shinichi Ishida, Hiroaki Nishi

Proceedings - 2013 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery, CyberC 2013 （IEEE）     266 - 272 2013年

　概要を見る

Extending Content Delivery Network (CDN) infrastructure that has features of router-based network management system (RNMS) is highly appealing and challenging. It allows developing a CDN architecture based upon standard design to ease interoperability, scalability, performance, and flexibility both on network monitoring and management controlled from a router. To better understand the system model, necessity, and the advantages of RNMS, this paper proposed an algorithm that distributed in to a special router called Service-oriented Router (SoR). The function of algorithm is to manage the effective and efficient number of replica server runs in the network. In CDN, minimizing the number of activated replica servers should be considered in order to reduce the operation cost of the system. We propose a semantic approached algorithm that has function to optimize the selection of active replica servers which managed from SoR. The algorithm has capability to find the best location of replica servers and performs load balancing among replica servers. Our simulation result indicates that the proposed algorithm can efficiently activate the replica servers according to user's request with 33.9% effective compared to other algorithm within about one millisecond RTT increase. © 2013 IEEE.

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Demand control of a pool by means of residual chlorine sensor

Tomoya Imanishi, Yasumasa Hayashi, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     6344 - 6349 2013年

ISSN  1553-572X

　概要を見る

Energy consumption is continuing to increase, especially the consumption of fossil fuels. It is important, therefore, to make use of our limited energy sources and reduce carbon dioxide emission. Some natural energy resources, such as solar power, have been well studied; however, they require complex systems and introduce energy fluctuations. On the other hand, demand side management (DSM) can also be studied from the consumer's point of view. One of the challenges associated with DSM is reducing the energy consumption of pumps in commercial buildings. Although water cycling systems have been well studied by large water departments, the knowledge is not generally used in most commercial facilities. Therefore, this study aims to control a water circulation pump to reduce energy consumption while maintaining water quality. This approach is applicable to buildings with pools or hot springs that are expensive to operate and maintain. Automation of water circulation systems has been well studied only by water departments. However, general water purification systems can be expensive and are highly complex. For these reasons, this paper constructs a low-cost automatic water management system to reduce management costs. An experiment was conducted to demonstrate an automatic water management system that will effectively cut water management costs using low-cost sensors. We also experimentally obtained some parameters to facilitate automatic water management. Finally, the experimental system was found to reduce electricity consumption by 8%/day and reduce the electric peak by 30%. © 2013 IEEE.

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Accurate indoor condition control based on PMV prediction in BEMS environments

Kenta Kuzuhara, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     8142 - 8147 2013年

ISSN  1553-572X

　概要を見る

Recently, there has been high demand for an efficient energy management system that decreases total energy consumption. The Great East Japan Earthquake of March 2011 resulted in the shutdown of nuclear power plants in Japan, thus limiting the supply of power. Since then, the need for an energy management system has become more pronounced in Japan. Such a situation warrants efficient energy consumption through the use of an energy management system. When heating, ventilation, and air conditioning are restricted, especially under peak-cut or peak-leveling control of electric power consumption, it should be ensured that the living environment is not uncomfortable for humans. However, in the existing methods, living environment comfort has not been considered practically in terms of the fundamental parameters, namely, volume, window size, and number of people in a given room, despite the considerable influence of these parameters on room amenity. In this study, we proposed a new control method that considers these parameters for maintaining the amenity index in indoor environments at a set value by predicting the predicted mean vote value. Furthermore, we set up a building energy management system in an office building in Kanagawa, Japan, to compare the proposed control method with an existing one. Two different cases were considered in this experiment: control using an existing method and control using the proposed method. The results show that the proposed method maintains the amenity index of the room at the desired level, while reducing peak and total power consumption levels. © 2013 IEEE.

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Feasibility study of service-oriented architecture for smart grid communications

Kenichi Takagiwa, Ryogo Kubo, Shinichi Ishida, Koichi Inoue, Hiroaki Nishi

IEEE International Symposium on Industrial Electronics （IEEE）     1 - 7 2013年

査読有り

　概要を見る

This paper proposes a service-oriented network architecture for next-generation power grids, i.e., smart grids. The proposed architecture includes Ethernet passive optical network (EPON)-based optical access systems and service-oriented routers (SoRs). The SoR function is embedded into any communication nodes for capturing, filtering, storing, selecting, calculating, and redirecting requests in network traffic. The maximum throughput of the developed SoR is 1.12 Gbps, and the size of its packet buffer is approximately 100 MB. To confirm the feasibility of the proposed service-oriented architecture for smart grid communications, the performance of a power grid model is evaluated using MATLAB/Simulink and SimPowerSystems Toolbox. © 2013 IEEE.

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SoR-based programmable network for future software-defined network

Kenichi Takagiwa, Shinichi Ishida, Hiroaki Nishi

Proceedings - International Computer Software and Applications Conference （IEEE）     165 - 166 2013年

査読有り,  ISSN  0730-3157

　概要を見る

The Future Internet architecture would be advanced and flexible depending on service requirements by program. The concept of Software-Defined Network (SDN) has a possibility to enable innovation while hiding much of the complexity on the networking design. SDN is mainly used by OpenFlow in real scenario, which can use up to layer-4. In this paper, we propose SDN which consider up to layer-7. To maintain flexible network and to get maximum benefit from networks, Service-oriented Router (SoR) was introduced. A SoR enables layer-2 to layer-7 information to be captured, analyzed, and stored and has a high-throughput database(DB) and is able to analyze all transactions on its interfaces. In addition, SoRs can provide APIs to access stored contents in order to enrich services. In our system, we make network programmable by considering layer-7 information, which can not be captured by using OpenFlow method. This feature will make future SDN more effective and convenient. © 2013 IEEE.

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Service-oriented router-based CDN system: An sor-based CDN infrastructure implementation on a real network environment

Janaka Wijekoon, Shinichi Ishida, Erwin Harahap, Hiroaki Nishi

Proceedings - International Computer Software and Applications Conference （IEEE）     742 - 747 2013年

査読有り,  ISSN  0730-3157

　概要を見る

Internet users are constantly demanding faster and higher quality services from their internet service providers. Therefore, for fast data delivery of such applications, Content Delivery Networks (CDNs) have been introduced. Most CDN providers use Domain Name Resolution (DNS) based request routing (RR) methods to find the nearest server for a particular client and it has both advantages and disadvantages. Importantly, disadvantages result high latencies of data delivery and network congestions. To maintain rich information in the Internet and to shift the current Internet infrastructure to an information-based open environment platform, Service-oriented Routers (SoRs) have been introduced. An SoR has a high-Throughput database and it is able to analyze all transactions on its interfaces. Therefore, we have used the basic functionalities of the SoR to diminish disadvantages of the DNS-based RR methods. Proposed system is independent from DNS-based RR and we have conducted experiments based on content-centric RR using the SoR basic functionalities and successfully evaluated and compared both of the round trip time (RTT) and the packet inter arrival time. Our results indicated that SoR-based method can reduce upto 40-50% latency in both connection initiation time and content migration time in-between servers. © 2013 IEEE.

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Service-oriented router simulation module implementation in NS2 simulator

Janaka Wijekoon, Erwin Harahap, Hiroaki Nishi

Procedia Computer Science （ELSEVIER SCIENCE BV）  19   478 - 485 2013年

査読有り,  ISSN  1877-0509

　概要を見る

The Service-oriented Router (SoR) is a router for next generation networks. This router has a high-throughput database and it has the capability to snoop all transaction in its interfaces. The SoR also provides an API which can provide stored content in order to enrich services. The SoR has the potential to shift the current Internet infrastructure to an information-based, open innovation platform. In order to evaluate the efficiency of SoR-based applications and services, a specific simulator is required. Though the NS2 simulator does not simulate payload handling, it is a well-known network simulator and there are many resources available for evaluations. In this research, we implemented three new modules for the NS2 platform to test the concepts of an SoR, an SoR agent, a packet container and a packet analyzer. The SoR agent can interconnect the application and physical layers of the NS2 module with an additional function that can handle user data as a real payload and attaches it to the IP packet. The packet container is an improved NS2 module that can attach user data and trace information. A successful simulation has been performed for end-to-end packet transfer with a 0.02s packet delivery delay compared to typical NS2 packet delivery. The NS2 router has been enhanced for packet stream analyzing and content centric packet re-routing. Content centric packet re-routing has been achieved with 0.01s additional delay for end-to-end packet delivery. Result shows that Deep Packet Inspection and content centric networking in an SoR-based network can be achieved. © 2013 The Authors. Published by Elsevier B.V.

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Router-based request redirection management for a next-generation content distribution network

Erwin Harahap, Janaka Wijekoon, Rajitha Tennekoon, Fumito Yamaguchi, Hiroaki Nishi

2013 IEEE Globecom Workshops, GC Wkshps 2013 （IEEE）     1007 - 1012 2013年

査読有り,  ISSN  2166-0069

　概要を見る

The increase in the amount of digital data transferred between contents Servers and Clients in a network causes problems created by congestion when downloading big web files, streaming media, etc. Content Delivery Networks (CDNs) are introduced to overcome such problems by redirecting the Clients request to the nearest Server. However, as the number of people accessing Internet increases rapidly, the performance of CDN is reduced, resulting in network congestion at times. To solve these problems, we propose an architecture in which a new management method is employed to redirect the Clients request using a content-based Router called the Service-oriented Router (SoR). This method is more effective than the currently implemented, traditional DNS-based request redirection (RR). The SoR is a special router that can perform a deep packet inspection of the packet streams. Our experiments were based on analytical modeling as well as test bed experiments, and they confirmed that the response time in the Router-based RR was less than that in the DNS-based RR by 23.3%. In addition, our test bed experiments showed that the RTT in the Router-based RR is less than that in the DNS-based RR by 7.7%. © 2013 IEEE.

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Real-time METs estimation for effective indoor amenity control in HEMS

Minako Ito, Hiroaki Nishi

IEEE International Symposium on Industrial Electronics （IEEE）     1 - 6 2013年

　概要を見る

In the regulation of heating, ventilation, and air conditioning (HVAC) for a peak cut or peak leveling control of electric power consumption, the amenity of the living environment should be considered. In the existing method, the metabolic equivalent (MET) value is not considered because of the substantial measurement costs and because a special infrastructure is required for both measuring the value by the MET meter and for communicating with the HVAC control server in the home energy management system (HEMS) or building EMS (BEMS). This paper proposes a method for measuring the MET value on a mobile device for accurately calculating the predicted mean vote (PMV). This method is designed as an iPod touch or iPhone application. The application has sufficiently reduced energy consumption for use as a mobile device application and is sufficiently accurate for use as an HVAC control. The availability and usefulness of both the designed application and the proposed MET measuring method is experimentally confirmed, and the reduction in energy consumption is estimated using an actual HEMS. © 2013 IEEE.

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Hardware-based hash functions for network applications

Fumito Yamaguchi, Hiroaki Nishi

IEEE International Conference on Networks, ICON （IEEE）     1 - 6 2013年

査読有り,  ISSN  1556-6463

　概要を見る

For rich network services, it is indispensable to reconstruct TCP stream in the middle of the network. In this reconstruction function, managing a large number of streams is a crucial as an embedded hardware for achieving high-throughput processing. In this case, hashing is a well-used solution as an ID key of TCP streams. Since CRC hashes have simple tree structure of XOR logics and are perfectly composed of combination logics, they can easily be hardware implemented and enables low-latency calculation of the hash values. Therefore, CRC hash has been used in network applications where low-latency and high speed operations are necessary. Some of their usages include data identification, load balancing, encryption, and checksum. Although CRC hashes may be well suited for hardware implementation, it is not the top choice when collision rates and distribution of hash values are considered. For some network workloads, CRC hashing shows very uneven distribution of hash values and can lead to decrease in the overall performance of network systems. In this study, two hashes, Jenkins hash and MurmurHash, are implemented on a FPGA as TCP connection manager and evaluated for their aptitude for hashing used in hardware-based network applications. © 2013 IEEE.

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GPU-based multi-stream analyzer on application layer for service-oriented router

Kazumasa Ikeuchi, Janaka Wijekoon, Shinichi Ishida, Hiroaki Nishi

Proceedings - IEEE 7th International Symposium on Embedded Multicore/Manycore System-on-Chip, MCSoC 2013 （IEEE Computer Society）     171 - 176 2013年

査読有り

　概要を見る

A service-oriented router (SoR) is a new router architecture that provides rich application-layer services to Internet users by extracting information from network traffic. SoR performs stream reconstruction and selection using string matching. After on-the-fly reconstruction of stream data, SoR extracts the required information using a software-based character string analyzer. For wire-rate string matching and for design flexibility, a software-based string-matching accelerator is required. A graphics processing unit (GPU) is a promising solution as a conventional cost-effective accelerator for use in a high-end router. Existing string-matching methods do not consider the multiple-stream processing and effective thread management required in a network application. We propose an accelerated string-matching method that is customized for a router and implemented a task controller that improves thread distribution depending on the status of core processes. © 2013 IEEE.

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環境快適性と消費電力量を考慮した家電制御最適化手法

中部 知久, 西 宏章

日本建築学会環境系論文集 （日本建築学会）  77 （ 682 ） 1011 - 1019 2012年12月

ISSN  1348-0685

　概要を見る

In the DSM (Demand Side Management) system, a control method for controlling electric appliances in living space should take account of environmental amenity. This paper focuses on a trade-off relationship between power consumption and environmental amenity. We proposed a new method to evaluate this relationship, and it enables to optimize the environmental amenity by air conditioning under the restriction of total power consumption. The proposed method was evaluated by using real environment. This evaluation shows the proposed could improve up to 27.4% in temporary summation of comfort index compared with an existing method.

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環境快適性と消費電力量を考慮した家電制御最化手法

西 宏章

建築学会環境系論文集 （日本建築学会）  7 （ 682 ） 1011 - 1019 2012年12月

研究論文（学術雑誌）, 共著, 査読有り

トラヒックからアプリケーションレイヤ情報の検索・抽出を可能とするソフトウェアの実装と評価

西 宏章

コンピュータソフトウェア （日本ソフトウェア科学会）  29 （ 4 ） 59-73 - 73 2012年11月

研究論文（学術雑誌）, 単著,  ISSN  0289-6540

　概要を見る

近年，ルータやゲートウエイが取得可能な情報を使って新たなサービスを提供する試みが提案，検討されている．従来，NIDS (Network Intrusion Detection System)構築のため，ゲートウェイ上でレイヤ7での情報検出を可能とするソフトウェア実装は存在したが，アプリケーションプロトコルのHTTP/1.1のgzip encodeやchunk encodeに対応し，情報の検索と抽出を主目的とした実装は公開されていない．そこで本論文ではlibpcapを利用してLinuxゲートウェイのethデバイスやpcapファイルのトラヒックからTCPストリーム再構築と前記HTTPのデコードを行い，文字列抽出を実現するオープンソース・ソフトウエアSLIM (Smart Linux Interface Monitor)を実装，評価した．SLIMにおいて使用メモリ量を削減するため，コンテキストスイッチを利用したパケット単位のTCPストリーム再構築を独自に実装した．評価結果より，SLIMはオンライン解析を行った場合，ゲートウェイ上で21.3Mbpsの処理が可能であり，pcapファイルを直接処理した上でPostgreSQLに保存した場合86.8Mbps, ファイルとして保存した場合1.12Gbpsを達成した．また，オフライン解析を行った場合，1.5TB・最大73万コネクションを含むコアネットワークの仮想トラヒックを解析可能であることを示した．この時，使用メモリ量は5.87GBであった．また，SLIMは研究室ゲートウェイで3ヶ月以上安定して連続動作に成功した．

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Effective Hash-based Filtering Architecture for Highthroughput Regular-expression Matching

Hayato Yamaki, Yasutsugu Nagatomi, NISHI HIROAKI

International Journal of Information and Electronics Engineering (IJIEE) 2 （ 5 ） pp.672-677 2012年09月

研究論文（学術雑誌）, 共著

Enhanced Patricia Tree with Reordering and Fast Incremental and Decremental Update Functions

西 宏章

International Journal of Information and Electronics Engineering (IJIEE) 2 （ 5 ） 656-660 2012年09月

研究論文（学術雑誌）, 単著

A Case for Routing Cache on HPC Switches

西 宏章

IEICE Electronics Express (ELEX) （IEICE）  1 （ 1 ） 49-53 - 53 2012年06月

研究論文（学術雑誌）, 単著,  ISSN  2187-0136

　概要を見る

Large many-core parallel applications become sensitive to communication latencies, suggesting the need for low-latency networks in high-performance computing systems. Switch delay dominates network latencies. To reduce the network latencies, we exploit routing cache on a switch. Routing decision based on off-chip CAM (Content Addressable Memory)-based table lookup imposes a significant delay, however, using on-chip small routing cache can bypass it when it hits. Our simulation results show that the only 256-entry routing cache hits 98% on over 4k-host systems with the matrix-transpose traffic, and the 1024-entry routing cache improves not only up to 16% of packet latency but also up to 18% of network throughput.

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Field Demonstration of Building Energy Management Systems

Tianmeng Shen, Daichi Kawashima, Ryogo Kubo, Masaru Ihara, Toshiro Togoshi, and, NISHI HIROAKI

International Journal of Energy Engineering 2 （ 4 ） 115 - 125 2012年

研究論文（学術雑誌）, 単著,  ISSN  2225-6571

The impact of routing cache on high-performance switches

Michihiro Koibuchi, Shin Ichi Ishida, Hiroaki Nishi

10th International Conference on Optical Internet, COIN 2012    40 - 41 2012年

査読有り

　概要を見る

Large parallel applications become sensitive to communication latencies, suggesting the need for low-latency networks in high-performance computer systems. Switch delay dominates network latencies, especially for a large number of small transfer data. To reduce the network latencies, we exploit routing cache on a switch. Routing decision based on off-chip CAM(Content Addressable Memory)-based table lookup imposes a significant delay, however, using on-chip small routing cache can bypass it when it hits. Our simulation results showed that 1,024-entry routing cache improves not only up to 13% of packet latency but also up to 18% of network throughput compared with no-cache switches. © 2012 IEICE Institute of Electronics Informati.

Estimation of the number of people under controlled ventilation using a CO<inf>2</inf> concentration sensor

Seiya Ito, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     4834 - 4839 2012年

ISSN  1553-572X

　概要を見る

Recently, many studies dealing with energy saving have been conducted from the viewpoint of mitigating global warming. However, most of them only consider energy saving and ignore the total environmental impact. It is necessary to provide a comfortable work space using efficient and optimized energy control, because excessive demand control can have a negative impact on the environment. It can also have a negative impact on working or learning efficiency. To provide a comfortable indoor environment, it is important to measure environmental indexes, including not only temperature, humidity, illuminance, and wind speed, but also CO2 concentration. Moreover, to forecast air conditioner demand, it is important to know the number of people in the controlled space. In this paper, we propose a new method to estimate the number of people in a ventilation-controlled environment by using a CO2 sensor. The proposed method will provide a demand control system that achieves more intelligent and accurate control of ventilation fans. © 2012 IEEE.

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SoR based request routing for future CDN

Janaka Wijekoon, Erwin Harahap, Hiroaki Nishi

2012 6th International Conference on Application of Information and Communication Technologies, AICT 2012 - Proceedings 2012年

査読有り

　概要を見る

Internet users are constantly demanding faster and higher quality services from their internet service providers. This results an increase in broadband services, and access to delivery of applications enriched in data become top priority. Therefore, for fast delivery of such applications, Content Delivery Networks (CDNs) have been introduced. The Internet has become a massive system consisting of enormous amounts of information. To maintain the rich information in the Internet and to achieve maximum benefit from networks, Service-oriented Routers (SoRs) have been introduced. A SoR has a high-throughput database and is able to analyze all transactions on its interfaces. In addition, SoRs can provide APIs for accessing stored contents in order to enrich services. CDNs generally use Request Routing (RR) methods to achieve low user latency by performing load balancing among servers. RR is accomplished by selecting the nearest server for a particular user. In this paper we implement a new RR infrastructure that is based on the content of packet streams. The proposed system is independent of DNS-based RR, which is the predominant RR method used by current CDN infrastructures. In our system, content-centric request re-routing with SoR is used. Experimental evaluation and comparison of the round trip time (RTT) result of our proposed system with DNS-based RR indicates that our system achieves 50-60% reduction in connection initiation time. The SoR based RR method is able to reroute packets without disturbing clients, which is not possible using existing RR methods. This feature will make future CDNs more effective and convenient. © 2012 IEEE.

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Service-oriented communication platform for scalable smart community applications

Ryogo Kubo, Tianmeng Shen, Toshiro Togoshi, Koichi Inoue, Hiroaki Nishi, Masashi Tadokoro, Ken Ichi Suzuki, Naoto Yoshimoto

IECON Proceedings (Industrial Electronics Conference) （IEEE）     3594 - 3599 2012年

ISSN  1553-572X

　概要を見る

This paper proposes a service-oriented communication platform enabling the provision of scalable smart community services. The proposed platform is managed using Extensible Markup Language (XML) that has advantages in terms of flexibility, cost-effective implementation and affinity with databases. In practice, the platform is embedded into distributed communication nodes, e.g. routers, switches and home gateways, and both existing IP services and smart community services are provided over public networks. In this research, as an application, a building energy management system (BEMS) using the platform is demonstrated. The feasibility of the network architecture with the platform is discussed based on experimental results of data acquisition and control in the BEMS demonstration. © 2012 IEEE.

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Real-time simulation of cooperative demand control method with batteries

Daichi Kawashima, Masaru Ihara, Tianmeng Shen, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     3588 - 3593 2012年

査読有り,  ISSN  1553-572X

　概要を見る

Currently, electricity generation requires both fossil energy resources and the supply of renewable energy. In addition, efficient energy management is necessary. This need became more pronounced in Japan after the Great East Japan Earthquake of March 2011. Since then, Japan's power supply has been limited because of the shutdown of nuclear power plants, and this has led to several problems. To deal with this problem, the effective use of renewable energies such as photovoltaic and wind power is required. Since these energy sources are unstable, batteries need to be introduced in the power grid for power supply leveling. However, the financial burden of introducing batteries on the demand side, such as in houses or buildings, is very high. To solve this problem, the required battery capacity needs to be reduced by controlling the air conditioners used by consumers in order to facilitate the peek-shift effect. In this study, we constructed a real-time simulation using a hardware-in-the-loop (HIL) system that can control air conditioners through power leveling with batteries. We propose two different cooperative demand control methods for comparison. These methods consider consumer comfort and the state of charge (SoC) of the batteries. The aim of this simulation was to compare three cases: no control, battery control, and control of both the air conditioner and the battery by a cooperative demand control method. This simulation showed that the cooperative control method achieves power consumption reduction and power leveling at the same time, which proves that the proposed method can reduce the battery capacity required for power leveling. © 2012 IEEE.

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Hardware acceleration and data-utility improvement for low-latency privacy preserving mechanism

Junichi Sawada, Hiroaki Nishi

Proceedings - 22nd International Conference on Field Programmable Logic and Applications, FPL 2012 （IEEE）     499 - 502 2012年

　概要を見る

With the recent growth in the quantity and value of data, data holders have come to realize the importance of being able to utilize information that is otherwise abandoned or concealed. In this situation, they face the difficulty of publishing data without revealing private information. One of the methods used to protect private information when publishing data is privacy-preserving method based on constraints known as k-anonymity and l-diversity. In this paper, we propose a hardware architecture composed of Ternary Content Addressable Memory (TCAM) and a cache mechanism to efficiently reduce the time required for executing the methods. An evaluation proves that an implementation of the proposed architecture on a reconfigurable device performs approximately 10-50 times faster than a RAM-based architecture and up to 60% of the information loss can be eliminated by using the cache mechanism. © 2012 IEEE.

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構造物ヘルスモニタリングシステムのためのデータバックアップ機構

松柴　由直西 宏章

建築学会環境系論文集 （建築学会環境系論文集）  76 （ 662 ） 439-447 - 447 2011年04月

研究論文（学術雑誌）, 単著,  ISSN  1348-0685

　概要を見る

建築構造物における継続的耐震性評価システムとして運営する際に必要なフォルトトレランシーを維持しつつ，地震発生による倒壊が起きた際においても，その貴重な計測データを極力システムで保持し将来の構造物設計に役立てるシステムについて提案するとともに，実モデルを利用した実験により耐故障性効果を確認している．

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A simulation study of electric power leveling using V2G infrastructure

Masaru Ihara, Tianmeng Shen, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     3224 - 3229 2011年

査読有り,  ISSN  1553-572X

　概要を見る

To cope with global energy-related problems, the effective use of renewable energy such as photovoltaic and wind power is required. As these energy sources are unstable, it is required to introduce batteries into the power grids. Vehicle to grid (V2G) is a technology that is receiving much attention as a method for achieving an efficient energy management system (EMS) by connecting electric vehicles (EVs) to an electric power grid. In this study, we constructed an EMS model using MATLAB/Simulink and determined the optimized capacity of the fixed batteries and EVs based on data sampled at an experimental site in terms of capital cost. Fixed batteries as well as EV batteries were modeled and evaluated using the actual parameters and constraints of the terminal. The main aim was to level the received energy and achieve the recharge level of the battery in one day to maintain a long battery lifetime. Through simulations, we determined the optimized capacity based on actually measured data. We could exploit the management method by considering the relation between fixed batteries and EV batteries. Using this relation, the proposed method could predict the optimized fixed or EV batteries capacity required. © 2011 IEEE.

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Evaluation of power consumption and comfort using inverter control of air-conditioning

Kyosuke Funami, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     3236 - 3241 2011年

ISSN  1553-572X

　概要を見る

Saving energy is indispensable in the solving of environmental problems such as global warming and resource depletion. In the household and office sectors, which are growing in terms of electric power consumption, it is desired to improve the efficiency of air conditioning because power consumption due to air conditioning is dominant particularly in summer when conditions of electricity usage are tight. However, the drawback with the excessive reduction in power consumption is the consequent reduction in indoor comfort levels and working efficiency. Therefore, it is important to reduce power consumption with comfort in mind. In our study, we carry out experiments on environmental measurement and control of an air conditioner by using the Keio university network oriented intelligent and versatile energy saving system (KNIVES). Three different control methods are used for evaluation of power consumption. The first method involves ON/OFF control of the air conditioner through its demand control terminal; this method is widely used. The second method involves infrared control in changing the temperature of the air conditioner by means of automatic infrared signals. The thirds method involves inverter control that changes the inverter power output of the air conditioner by using a special demand control unit. Power consumption and comfort are compared and evaluated for each of the three methods. © 2011 IEEE.

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Implementation and substantiation of energy management systems for terminal buildings

Tianmeng Shen, Toshiro Togoshi, Hiroaki Nishi

IEEE International Conference on Emerging Technologies and Factory Automation, ETFA （IEEE）     1 - 4 2011年

査読有り,  ISSN  1946-0740

　概要を見る

Many different approaches are currently used in the field of network integrated control systems known as the Smart Grid. We implemented an energy management system with the aim of developing a future standard for this area. It is difficult to connect a heterogeneous system containing different standards, even if standardized technologies are available. A metastandard concept is proposed and substantiated to overcome this problem. The concept was substantiated in an energy management system constructed at the Fukue port terminal building in Goto City, Nagasaki Prefecture. This system uses a variety of devices produced by seven different companies. An air-conditioning control system to reduce carbon dioxide emissions was implemented and substantiated as an application of the proposed system. Our results demonstrate the effects of a common platform and its advantages. © 2011 IEEE.

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Self-organized Link State Aware Routing for Multiple Mobile Agents in Wireless Network

Akihiro OdaNISHI HIROAKI

IEICE Transaction on Communication, Special Issue Implementation, Experiments, and Practice for Ad Hoc and Mesh Networks E93-B （ ０８ ） 2012-2021 2010年08月

研究論文（研究会，シンポジウム資料等）, 共著

　概要を見る

自由に桁数を選択可能なハッシュ関数を利用し，そのORを取ることでグルーピングを行うとともに，アドホックネットワークにおけるルーティングテーブルをHELLOメッセージ中の有効ノード情報を削減し，軽量な分散ルーティングテーブル構築手法を提案し評価している．

Hardware Architecture for Supporting High-speed Database Insertion on Service-oriented Router for Future Internet

Tomoaki Makino, Michihiro Koibuchi, Hideyuki Kawashima, Koichi Inoue, Hiroaki Nishi

Proc. of the 2010 International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA’10) （CSREA Press）     402 - 407 2010年06月

査読有り

環境センサを利用した在室人数推定手法

立川　智一，西　宏章

日本建築学会環境系論文集 （日本建築学会）  75 （ 650 ） 355-358 - 362 2010年04月

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  1348-0685

　概要を見る

The estimation of the number of people is useful for various situations. In this paper, hybrid estimation method of the number of people in a room is proposed. This estimation method is achieved by using CO₂ sensor and motion sensor. Adaptive adjusting method of hold time for motion sensor is also proposed for its self-calibration. Proposed method was implemented on an energy management system and evaluated in a classroom environment. This evaluation proves that proposed method can improve the precision from 0.9 in the previous method to 0.4 in the proposed method at the number of people.

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トラフィック局所性を利用した拡張パトリシアツリーの提案と評価

明石　大，西　宏章

電子情報通信学会論文誌 J93-B （ 2 ） 242-250 2010年02月

研究論文（学術雑誌）, 単著, 査読有り

伝達遅延を考慮したシステム結合の一表現法

名取 賢二, 西 宏章, 大西 公平

電気学会論文誌. D, 産業応用部門誌 （一般社団法人 電気学会）  170 （ 1 ） 45 - 54 2010年01月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  0424-7760

　概要を見る

This paper presents an expression of system connection considering transmission delay. In a research field of decentralized system or information system, expression method of the system connection is very important issue. Therefore some expression methods of system connection have been proposed so far. However those expressions are mainly based on binary operation and can not consider the transmission delay on connection paths although the concept of time is efficient for expression of system connection.<br>In this paper, expression methods of system connection considering transmission delays on the paths are proposed. Those expressions are based on exponential-type expression and can express both connections and transmission delays. Furthermore the expression that can express connections, transmission delays and past subsystems is also proposed. As one example of the application of proposed expressions, application for path selection of the design of network-based control system is described.

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コールドブートアタックに対する防御手法の提案

池原　幸司，西　宏章

電気学会情報通信部門誌 （一般社団法人 電気学会）  130 （ 8 ） (to be appeared) - 1356 2010年

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  0385-4221

　概要を見る

This paper proposes four different methods for preventing cold boot attacks. These attacks exploit DRAM remanence to acquire private information stored in a memory. DRAM modules can keep stored values for many seconds without a power supply, in particular at low temperature. To address cold boot attacks, circuit-shorting method, SRAM preservation method, and cell selection method are proposed. The integrated method of these methods is also proposed because these methods are independent and can be achieved together. These proposed methods are evaluated by using actual testbeds.

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Self-organized Link State Aware Routing for Multiple Mobile Agents in Wireless Network

Akihiro Oda, Hiroaki Nishi

IEICE TRANSACTIONS on Communications E93-B （ 8 ） 2012-2021 2010年

研究論文（学術雑誌）, 単著, 査読有り

A regular expression processor embedded in service-friendly router for future Internet

Yasutsugu Nagatomi, Michihiro Koibuchi, Hideyuki Kawashima, Koichi Inoue, Hiroaki Nishi

Proceedings of the International Conference on Parallel Processing Workshops （IEEE Computer Society）     82 - 88 2010年

査読有り,  ISSN  1530-2016

　概要を見る

For the future application-friendly Internet, we have presented a router architecture that enables to interact with a variety of rich services. The proposed router snoops a traffic data stream, inspects the packet payload as well as packet headers, and stores the designated data in the associated database. The service-friendly router uses the technology of DPI (Deep Packet Inspection) for enriching services. For this purpose, high-throughput regular expression processing becomes a crucial component embedded in the router in order to extract the required information from traffic streams. Moreover, target patterns of the regular expression processing can be dynamically and frequently updated according to the applications requests. In this paper, we mainly focus on the design and evaluation of the high-throughput regularexpression processor. It accelerates the processing performance of OR matching (pipe(\)-based matching) that is familiar in various emerging applications of future Internet. The proposed regular-expression processor achieves a low overhead processing under the condition that the updates of the regularexpression patterns are frequently issued. Evaluation results show that the proposed processor achieves 6.0-Gbps throughput of regular-expression matching when using 45nm standard cell library. © 2010 IEEE.

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Distributed Demand Side Management system for home Energy Management

Yukio Suhara, Tomohisa Nakabe, Gouki Mine, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     2430 - 2435 2010年

ISSN  1553-572X

　概要を見る

Energy Management System, including Demand Side Management, are contributing to energy saving. However, power demand for home consumers, unlike large power consumers, is considered difficult to control each electric device because these power demands depend on consumer's behavior. Therefore, predicting power demand eagerly requested. KNIVES (Keio University Network oriented Intelligent and Versatile Energy saving System) is an ICT based demand side management system and controls electric power by using distributed and cooperative power control algorithm. We propose a management system for households with a smart circuit breaker box, which can measure power consumption of each outlet and enables integrated control by using KNIVES. In addition, I propose prediction method of demand power in a household by using proposed system. © 2010 IEEE.

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Construction of energy measuring system in a university for cluster Energy Management System

Yuto Kamiyoshi, Tomohisa Nakabe, Gouki Mine, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     2423 - 2429 2010年

ISSN  1553-572X

　概要を見る

To deal with environmental problems such as global warming and depletion of energy resources, energy conservation measures in the civilian sector and the spread of renewable energy are required strongly. As a next-generation energy system to achieve them, Cluster Energy Management System (CEMS) is beginning to be studied in Japan. CEMS is the energy management system, which cooperates with various dispersed power sources and buildings using information technology. CEMS monitors and adjusts energy supply and demand in real-time to form the best combination of them, and achieves high efficiency energy usage. In this study, the electricity energy measurement system using KNIVES (Keio University Network oriented Intelligent and Versatile Energy saving System) was build in Keio University Shonan Fujisawa Campus (SFC). In addition, it is declared that this system can predict electric power demand based on the past data obtained from itself. © 2010 IEEE.

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Construction method of dynamic microgrid by using optimized grouping method

Gouki Mine, Robert Borer, Friederich Kupzog, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN)    780 - 785 2010年

ISSN  1935-4576

　概要を見る

Dynamic microgrid was proposed in our laboratory in order to utilize distributed power sources effectively. It means that structure of microgrid is varying according to demand fluctuation. To realize the dynamic microgrid, it is indispensable to obtain both energy demand and supply and keeps balance them by using ICT based sensor network. KNIVES (Keio University Network oriented Intelligent and Versatile Energy saving System) is an ICT based supply and demand side management system that supports distributed and cooperative power control. In this study, KNIVES is introduced to actual consumers such as care facility, school and store as a platform of dynamic microgrid. Topology of the microgrid is changeable dynamically, and it is determined to conduct optimized calculation by referring energy consumption data and targeted value set measured from individual groups. This paper describes construction method of the dynamic microgrid and evaluation of feasibility and availability from a standpoint of calculation cost. © 2010 IEEE.

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Effective data sharing system for fault tolerant structural health monitoring system

Yoshinao Matsushiba, Hiroaki Nishi

International Workshop on Advanced Motion Control, AMC （IEEE）     76 - 81 2010年

　概要を見る

Structural Health Monitoring (SHM) system is a promising technology to determine the health condition of a structure and localize its damage. SHM system is widely used, especially in gigantic structures for its strong requirements of safety. Many researches about SHM system have been conducting. However, conventional SHM system did not take account of an accidental collapse caused by earthquake. As a result, there is a possibility that sensor nodes, network links, and a center server cause failures in processing or storing of data gathered in the building. These failures may lose important data that contains useful information for post-analyzing the collapse. The data includes when, where and why the structure is damaged and collapsed. Theses information have a great deal of potential for preventing similar damage or collapse and it will make great contribution to accelerate future structural researches. To solve the problem of data losses in a damage, data sharing system for SHM system is proposed. This system shares data within sensor nodes. The proposed system achieves the following three processes; node search, backup node selection and backup data transfer process. It is important to conduct these processes under the condition of limited resources due to small and not powerful sensor nodes. Backup node selection is an important process of this system. This paper mainly focused on this selection. Round-trip time, a size of free memory space of backup nodes and value of displacement caused by vibration are used for the selection. In this paper, the selection method based on displacement was checked. An experiment was conducted by using practical sensor nodes and acceleration data. From the result of this experiment, proposed system could share data by using selection method based on displacement. © 2010 IEEE.

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Multi-context-aware cache accelerating processing on network processors for future internet traffic

Airi Akimura, Hiroaki Nishi

International Conference on Advanced Communication Technology, ICACT （IEEE）  1   377 - 382 2010年

査読有り,  ISSN  1738-9445

　概要を見る

The next-generation backbone routers need large-bandwidth communication capability because of increased future Voice over Internet Protocol (VoIP) services. Providing these or other future ubiquitous services will require new Network Processor (NP) designs, since these protocols or services are expected to require enormous increases in processing power in order to address their fine-grain communication pattern. These improvements of processing power will not be enough for future NP designs due to the requirements of cost reduction and lower power consumption. To meet these requirements, the cache mechanism has received increasing attention in NP design. Cache can reduce the load and time needed for table lookup by taking advantage of temporal localities in network traffic. For these reasons P-Gear, an advanced cache-based network processor, has been proposed by our laboratory. P-Gear, which provides a sophisticated cache architecture, can be used not only for table lookup but also for determining processing results, and achieves high-speed packet processing. In this paper, the cache architecture of P-Gear is shown and an extended cache mechanism called Multi-Context-Aware cache is proposed. Multi-Context-Aware cache can improve the speed of packet processing because it can control cache entry by analyzing the packet header and payload. To evaluate the validity of this proposed method, simulators of SIP (Session Initiation Protocol)-Aware cache, IKE (Internet Key Exchange)-Aware cache and FTP (File Transfer Protocol)-Aware cache were designed as subsets of Multi-Context-Aware cache. According to the simulation results, SIP-Aware, IKE-Aware and FTP-Aware cache can all make contributions to improving the cache hit rate by managing cache entry. In addition, they all can reduce processing unit requirements.

Link state aware routing for multiple mobile robots in wireless sensor network

Akihiro Oda, Hiroaki Nishi

Proceedings of the 9th IASTED International Conference on Parallel and Distributed Computing and Networks, PDCN 2010    143 - 149 2010年

　概要を見る

In recent years, instead of wired communication, wireless communication technology has been utilized in many applications. Particularly, wireless sensor networks can be utilized as a communication medium of multiple mobile robots for environmental monitoring, security service, space exploration etc. In this paper, to accomplish reliable packet routing in mobile ad-hoc network, a novel QoS sensitive routing algorithm is discussed. Wireless network topology could be changing dynamically by robot movement, radio disturbance or fading in continuously shifting situation. Therefore, a packet routing algorithm should guarantee QoS by using some quality indicators of a wireless network. In proposed routing algorithm, routing table is constructed by using Received Signal Strength Indicator(RSSI) and the table information is periodically flooded in the network. Novel hash based routing entry management by using extended-MAC address can eliminate the overhead of message flooding. An analysis of the collision of hash values contributes to determine the length of the hash values, which is minimum required. Simulations are conducted to evaluate the effectiveness of proposed algorithm and to validate the theory in general wireless network routing algorithm.

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Implementation of lossy haptic data compression using integer DCT to FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     1726 - 1731 2010年

査読有り,  ISSN  1553-572X

　概要を見る

In this paper, lossy compression based on Integer DCT (Discrete Cosine Transform) for haptic data is presented and implemented to an FPGA (Field Programmable Gate Array). The lossy data compression accomplishes to reduce data size of the haptic data. In the lossy data compression, DCT-based techniques are often used. The Integer DCT (IntDCT) achieves the operation of the DCT with the format of integer. The compatibility of the IntDCT with the FPGA is therefore high. The lossy compression method is applied to a bilateral control system and the efficacy is confirmed by experiments. © 2010 IEEE.

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Failure prediction method for network management system by using Bayesian network and shared database

Erwin Harahap, Wataru Sakamoto, Hiroaki Nishi

8th Asia-Pacific Symposium on Information and Telecommunication Technologies, APSITT 2010 2010年

　概要を見る

Network Management System (NMS) is a service that employs a variety of tools, applications, and devices to assist network administrators on monitoring and maintaining network. Keeping the network in high quality of service is the main purpose of NMS. This paper proposed a method to solve the network problem by making a prediction of failure based on network-data behavior. The prediction represented by conditional probability generated by Bayesian network. Bayesian network is a probability graphical model for representing the probabilistic relationship among a large number of variables and doing probabilistic inference with those variables. In order to describe how the prediction works, we discuss the prediction result by simulation on network congestion.

Environmental-amenity aware controller for demand side management

Tomohisa Nakabe, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN)    798 - 803 2010年

ISSN  1935-4576

　概要を見る

Deterioration of indoor condition is confirmed by decreasing efficiency of working in earlier study. Maintaining indoor condition is an important factor to control electric appliances in living space. This paper focuses on a trade-off relationship between power consumption and environmental amenity. In DSM (Demand Side Management) system, a control method for controlling electric appliances should aware environmental amenity. In addition, life styles of the system users differs request of demand control policy. In this policy, there are three elements of control, power consumption control, environment control, and user defined control. Proposed control method integrates these elements of the control policy. In addition, the proposed method enables to compare some operational methods. Simulation results suggest a possible beneficial effect of the proposed method in the environmental-amenity aware DSM. © 2010 IEEE.

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パケットストリームの正規表現処理を可能とするネットワークプロセッサ

永冨 泰次, 石田 慎一, 原島 真悟, 鯉渕 道紘, 川島 英之, 西 宏章

情報処理学会研究報告. 計算機アーキテクチャ研究会報告 （情報処理学会）  184 （ 21 ） U1 - U9 2009年08月

ISSN  0919-6072

　概要を見る

正規表現は，ネットワーク侵入検知システム （NIDS） などをはじめ様々なネットワークアプリケーションで広く使われている．しかしこれらの多くはソフトウェアベースのため処理速度が遅くネットワークのサービス品質に影響を及ぼしている．高速な処理を妨げる要因の一つは処理時間の大半を占めるパターンマッチングである．NIDS のパターンマッチングに用いられるパターン数は膨大であり，かつ複雑な正規表現も含まれている．このような膨大かつ複雑な正規表現を高速で処理できるエンジンのニーズは高い．本論文では膨大なパターン処理を可能とするパターン絞り込み機構を提案する．Regular-expression is widely used in various network applications, such as a network intrusion detection system (NIDS). However, high-throughput regular-expression execution couldn't achieve enough processing throughput because most of NIDSs have been implemented by software. Pattern matching function, which is a part of regular-expression processing， requires comparatively longer processing time. A huge amount of patterns are used for this pattern matching in NIDS. High-throughput processing engine are strongly required in order to execute a large number of complicated regular expression. In this paper, a pattern filtering architecture is discussed that enables to achieve a large number of patterns matching.

Implementation of Bilateral Control System Based on Acceleration Control Using FPGA for Multi-DOF Haptic Endoscopic Surgery Robot

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi, Toshikazu Kawai, Yasuhide Morikawa, Soji Ozawa, Toshiharu Furukawa

IEEE Trans. on Industrial Electronics （IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC）  56 （ 3 ） 618-627 - 627 2009年03月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  0278-0046

　概要を見る

Bilateral control systems are strongly required to apply to endoscopic surgeries. It is necessary that the system has enough degrees of freedom for applying various operation procedures including endoscopic surgery. When the degrees of freedom of the system are increased, the amount of control calculation is also increased, and it is hard to keep sampling periods short. The bilateral control systems, however, require comparatively shorter sampling periods, particularly the control system based on an acceleration control system. Hence, it is a difficult issue to increase the degrees of freedom of the bilateral control system. In this paper, the sampling period is kept short in the multi-degree of freedom system by using field programmable gate arrays as processors. The bilateral control system based on the acceleration control system is implemented in a robot system, which has 12 DOF, and some experimental results are shown, and the errors between the response of the master and slave robots are discussed. © 2009 IEEE.

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Design of acceleration control system considering current dynamics

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi

Proceedings of the IEEE International Conference on Industrial Technology （IEEE）     591 - 596 2009年

査読有り

　概要を見る

Sampling periods in digital control systems have been shortened thanks to the development of both hardware and software technologies. In recent years, FPGA (Field Programmable Gate Array) has been applied to robot systems to achieve hard real-time system with short sampling periods. Due to the short sampling periods, the effect of the time quantization has been reduced. Some other hardware restrictions, however, become critical issue. In this paper, current dynamics in motor driver is considered as the hardware restriction. The current response dynamics acts as a low-pass filter, and it can be the restrictions of performance improvement. In the proposed method, the dynamics is modeled as low-pass filter, and the modeled dynamics is compensated by a phase-lead compensator. The tracking performance in an acceleration control system is improved by the proposed method. The effectiveness of the proposed method is validated through simulations and experimental results.

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Evaluation of cooperative demand control system on micro grid

Gouki Mine, Toshihiko Handa, Tomokazu Tachikawa, Yuji Watanabe, Jun Ichi Ichimura, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     3593 - 3598 2009年

ISSN  1553-572X

　概要を見る

KNIVES (Keio University Network oriented Intelligent and Versatile Energy saving System) is an IT based supply and demand side management system that supports distributed and cooperative power control. In this study, KNIVES is constructed on a real experimental facility of microgrid. The facility includes some distributed power generator and controllable/uncontrollable loads. It is also connected with general power grid. Therefore, it can introduce the electric power from the power grid when the power supply is insufficient. An experiment of demand control was achieved in this facility and the affectivity of KNIVES was confirmed. In this experiment, error ratio of demand balancing with distributed and cooperative demand controls were evaluated and compared with that without the demand control. ©2009 IEEE.

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Quality of Connectivity Guarantee of ZigBee based Wireless Mobile Sensor Network

Akihiro Oda, Tomohisa Nakabe, Hiroaki Nishi

2009 7TH IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS, VOLS 1 AND 2 （IEEE）     452 - 457 2009年

査読有り,  ISSN  1935-4576

　概要を見る

In recent years, instead of wired communication, wireless communication technology has been utilized in many applications. Particularly, sensor networks are used in cases such as environmental monitoring, security service, space exploration etc. In this paper, motion planning and keeping connectivity of multiple robots distributed in a ZigBee based sensor networks are discussed in order to sense their unknown surroundings. The multiple robots distributed in a ZigBee based sensor network exchange information each other over the wireless sensor network and accomplish cooperative tasks in a closed area. In a rescue task, it changes dynamically according to the continuously shifting situation. In this case, the robots need to keep connectivity between other robots in order to accomplish the tasks in the real world. The proposed method enables mobile robot to be controlled under non-holonomic constraint and it is controlled based on the indicator of communication connectivity, which is related to the quality of communication as a real-time and real world application.

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Lightweight data duplication for fault tolerant Structural Health Monitoring System

Yoshinao Matsushiba, Hiroaki Nishi

IFAC Proceedings Volumes (IFAC-PapersOnline) 42 （ 3 ） 255 - 258 2009年

ISSN  1474-6670

　概要を見る

Structural Health Monitoring (SHM) is a key technology for determining the health condition of structures, such as buildings and bridges. SHM is widely used especially in gigantic structures due to the requirements of safety. However, conventional sensor network system for SHM did not take account of an accidental collapse. As a result, there is a possibility that a sensor network node, a network link, and also a center server cause failures in processing or storing of data gathered system. These failures may lose important data that contains useful information for a post-analyzing of the collapse. To solve this problem, a lightweight data duplication system for SHM that prevents the data failures or loss is proposed. Proposed system consists of three functions; node search, backup node selection and backup data transfer function. In backup node selection, round-trip delay and a size of free memory space of backup nodes are used.

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Haptic communication system using FPGA and real-time network framework

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     2931 - 2936 2009年

査読有り,  ISSN  1553-572X

　概要を見る

In this paper, a scheme for a haptic communication system is proposed by using an FPGA (Field Programmable Gate Array) and real-time network framework, RTnet. In the haptic communication system, the FPGA is used as a motion control processor, and the Linux-based real-time network framework is applied to the communication line between a master and a slave robot. The FPGA can execute control calculations in a short interval. Sending a large number of packets in a short period is, however, not acceptable for the communication line. In the haptic communication system, the FPGA execute the control calculation in every 50 μs, and the packets are sent in every 1 ms to prevent network congestion. The degrees-of-freedom(DOF) of the haptic device can be increased without increasing the number of sending packets, since the data of the each DOF is packed into one packet in a Linux module. In this paper, a master-slave haptic communication system is developed. The master side consists of a haptic device, whereas the slave side consists of a virtual haptic device and a virtual environment. The validity of the haptic communication system is shown through an experiment. ©2009 IEEE.

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バイラテラル遠隔操作における操作性向上のための重力補償

武井 貴義，下野 誠通，久保 亮吾，西 宏章，大西 公平

電気学会産業応用部門誌 （一般社団法人 電気学会）  128-D （ 6 ） 767 - 774 2008年06月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  0913-6339

　概要を見る

In this paper, the estimation method of only gravity and the compensation method of only the disturbance caused by gravity are proposed. The proposed method is able to estimate gravity, even when the system has the unknown posture. The proposed method is based on the concept of &ldquo;environment quarrier&rdquo;. Then, environment quarry is expanded to multilateral control. In this paper, two dummy robots that are the environment quarrier are implemented besides master-slave system, in order to abstract only gravity disturbance. The proposed method is adaptable, even when mass of master system differs from one of slave system. To verify the viability of the proposed method, experimental results are shown.

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Development of multi-degree-of-freedom bilateral forceps robot system using FPGA

Ena Ishii, Seiichiro Katsura, Hiroaki Nishi and Kouhei Ohnishi

Electronics and Communications in Japan （WILEY）  91 （ 6 ） 23 - 33 2008年06月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  1942-9533

　概要を見る

Fast growing use of minimally invasive endoscopic surgeries called for development of robots assisting in such procedures. However, existing surgical robots cannot transmit tactile sensation to the operator. To overcome this shortcoming, a bilateral teleoperation method was developed making it possible to accurately convey tactile sensation in single-degree-of-freedom forceps robots. This paper deals with the development of a multi-degree-of-freedom bilateral forceps robot system for surgical procedures which can adapt to actual conditions of the surgery.Bilateral teleoperation of multi-degree-of-freedom robots requires exchange of environmental information between master and slave devices in common coordinates. In this study we adopted mode coordinates which are better related to the motion of the robot. We also proposed a method to decouple the mechanical interference in mode coordinates. An FPGA-based controller introduced in this study makes it possible to reduce data processing time and to use hardware-based real-time control. As a result, multi-degree-of-freedom force feedback is attained.The experimental results show the viability of the proposed method. (C) 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(6): 23-33, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10118

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Semantic router using data stream to enrich services

Koichi Inoue, Dai Akashi, Michihiro Koibuchi, Hideyuki Kawashima, Hiroaki Nishi

International Conference on Future Internet Technologies (CFI08)    20 - 23 2008年06月

査読有り

Realization of acceleration control using multirate sampling method

Mariko Mizuochi, Toshiaki Tsuji, Hiroaki Nishi, and Kouhei Ohnishi

Electrical Engineering in Japan （WILEY）  192 （ 4 ） 72 - 81 2008年03月

研究論文（学術雑誌）,  ISSN  0424-7760

　概要を見る

This paper focuses on the realization of high-performance motion control based on acceleration control. The characteristics of acceleration control are investigated and the relationship between the performance and sampling frequency of the system is discussed. This paper then describes that a higher sampling frequency is required for acquisition of output information than for updating the input value. Based on this idea, a new multirate sampling method for an acceleration control system is proposed. A disturbance observer for the multirate system is designed by adopting a new definition of disturbance torque. A bilateral system is introduced as a preeminent example of a system that requires robust acceleration control. Both simulations and experiments are performed on the system, and the validity of the proposition is verified by the results. © 2007 Wiley Periodicals, Inc.

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An approach to acceleration estimation using FPGA

Hiroyuki Tanaka, Hiroaki Nishi, Kouhei Ohnishi

IEEE International Symposium on Industrial Electronics （IEEE）     1959 - 1964 2008年

査読有り

　概要を見る

the field of motion control, robustness is an important issue to accomplish desired motion of robots. To achieve robust motion control, acceleration control has been studied. In the acceleration control, disturbance observer is used to estimate and compensate disturbance force applied to an actuator. In the disturbance observer, the disturbance is estimated with calculating acceleration based on velocity/position information, and the estimated disturbance is obtained through a low-pass filter. To achieve accurate disturbance estimation, higher cut-off frequency of the low-pass filter and exact acceleration information are required. To set higher cut-off frequency of the low-pass filter, shortening sampling period is an effective method using FPGA as a motion control processor. However, short sampling period generally deteriorates the resolution of the velocity/acceleration information. This means that the estimated disturbance can include large error. In this paper, an acceleration estimation method is proposed to improve the resolution of acceleration in systems whose sampling period is very short. The validity of the proposed method is demonstrated by simulation and experimental results. © 2008 IEEE.

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Cooperative distributed demand control by environmental sensor network estimating the number of people by co<inf>2</inf> concentration

Tomokazu Tachikawa, Akihiro Oda, Toshihiko Handa, Junichi Ichimura, Yuji Watanabe, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) （IEEE）     336 - 341 2008年

ISSN  1935-4576

　概要を見る

KNIVES is a system for providing balanced power supply and effective demand control. This system controls the power of electric devices over the Internet, due to reduce total power consumption. For the control, KNIVES also considers indoor environmental affinity by using environmental sensors. In this paper, CO2 sensor is implemented on KNIVES terminal and it enables to measure CO2 concentration for assessing indoor vitiation. This paper verifies the effectiveness of this sensor by estimating the number of people. Also, the number of people is one of the parameter for effective control. Existing estimating method for counting the number of people, however, is difficult to install in a existing building. This paper describes the new estimating method for the number of people by CO2 concentration. As a result, this method can accomplish accurate measurement, and it can be applied to various applications for a future demand control. ©2008 IEEE.

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Haptic endoscopic surgery robot utilizing FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi, Toshikazu Kawai, Yasuhide Morikawa, Soji Ozawa, Toshiharu Furukawa

International Workshop on Advanced Motion Control, AMC （IEEE）  1   601 - 606 2008年

査読有り

　概要を見る

In late years, techniques and instruments for endoscopic surgery have been developed. The endoscopic surgery is a minimally invasive surgery, hence the Quality of Life (QOL) of patients can be improved. The endoscopic surgery still has, however, great difficulty for surgeons despite the development of the techniques and the instruments. To solve the problem, it has been studied to apply the technology of robotics to the endoscopic surgery. In this paper, a multi-degree of freedom haptic endoscopic surgery robot is developed aiming at the practical application of applying the robotics technology to the endoscopic surgery. The developed robot is a master-slave type robot, and a bilateral control system based on acceleration control is implemented. To achieve a short sampling period of the control calculation, FPGAs are utilized as processors. The validity of the developed robot is verified through some experimental results. © 2008 IEEE.

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Table-based scheduling method for distributed demand side management

Toshihiko Handa, Akihiro Oda, Tomokazu Tachikawa, Yuji Watanabe, Jun Ichi Ichimura, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     2748 - 2753 2008年

ISSN  1553-572X

　概要を見る

Internet based demand and supply control system is expected as an effective solution for saving fossil fuels by controlling power consumption automatically with taking account of environmental information. KNIVES is one of this systems and it uses distributed and cooperative power control algorithm. In 2007, the latest prototype of KNIVES has been developed and be operated so as to evaluate in real environment. KNIVES aims to improve the total efficiency of energy utilization in general household. The distributed and cooperative control is considered to improve the advantages of demand control system even if the controlled building is a small-scale customer. In this paper, the table-based scheduling method adapted to the distribute DSM is introduced. Furthermore, the enhancement of this method in order to aware environmental amenity is also indicated. © 2008 IEEE.

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Structural health monitoring system considering fault-tolerance

Yoshinao Matsushiba, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) （IEEE）     330 - 335 2008年

ISSN  1935-4576

　概要を見る

Structural Health Monitoring (SHM) system uses a number of sensors for a precise prediction. This prediction enables to provide early indication of vulnerability of a structure and the timing of reinforcement in order to prevent future collapse. SHM systems are now widely spreading in infrastructures. However, conventional SHM systems did not take account of accidental collapse. There is a possibility that sensor node goes down or network goes offline. If sensor nodes are broken by damage, important data, stored in the nodes will have lost. To prevent the data loss, this paper proposes data-distributed fault-tolerant sensor network system for a SHM system. Proposed system consists of three functions, PING (Packet InterNet Groper) based network monitoring function (PNM), backup node selecting function (BNS) and socket communication function. Proposed system is implemented on PCs and practically evaluated in a laboratory environment on terminals of KNIVES, which is a test bed of sensor network system. As a result, Data sharing process on PC and KNIVES was confirmed and proposed method can provide a light-weight fault-tolerant system taking account of accidental collapse. ©2008 IEEE.

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Perfect Classified Channel retaining DC balance for high-throughput communication

Hiroki Matsuoka, Kouichi Inoue, Hiroaki Nishi

2008 International Symposium on Information Theory and its Applications, ISITA2008 （IEEE）     1273 - 1278 2008年

査読有り

　概要を見る

In this paper, a practical architecture of physical layer for preventing from a leak of information, named Perfect Classified Channel (PCC), is proposed. PCC is a hardware- based Layer-1 encryption system and it prevents leak of not only packet information but also existence of packet. PCC can be used as high-throughput communication path without using 8B/10B or 64B/66B coding algorithm in order to achieve DC balancing, by using AES circuit fully made of logic gates. PCC establishes Hop-by-Hop classified channel for data transmission between routers, switches, or nodes. This paper confirms the DC balancing ability of PCC and shows the detail of its hardware architecture.

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KNIVES: A distributed demand side management system - integration with ZigBee wireless sensor network and application -

Toshihiko Handa, Akihiro Oda, Tomokazu Tachikawa, Junichi Ichimura, Yuji Watanabe, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) （IEEE）     324 - 329 2008年

ISSN  1935-4576

　概要を見る

KNIVES is proposed as Internet based demand and supply control system and controls power by using distributed and cooperative power control algorithm. However, if KNIVES aims to maintain indoor environmental amenity, installed locations and the numbers of environmental sensors are critical issues. Wireless sensor network is useful to measure environmental data of various points where a wired sensor is not available or cost of wired installation is expensive, and makes it easy to install or to relocate the sensors. In this paper, we implement ZigBee wireless sensor network and make operational test to discuss about the application of demand control method by using wireless sensor network. Furthermore, we propose some demand control application with ZigBee, customized environment-based control and head-count-based control, to make DSM more efficient. ©2008 IEEE.

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Implementation of multirate acceleration control based bilateral control system including mode transformation on FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     2465 - 2470 2008年

査読有り,  ISSN  1553-572X

　概要を見る

FPGA has been focused on as a controller of robot systems. Haptic robot system based on bilateral control system is one of the significant applications using the FPGA. In this paper, the bilateral control system including mode transformation is implemented on the FPGA. The bilateral control system is based on acceleration control system. The mode transformation is a transformation between robot mode space and operational mode space. Furthermore, multirate sampling method is introduced to consider hardware limitation. Some experimental results are shown in order to verify the validity of the implementation. © 2008 IEEE.

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Martini: A Network Interface Controller Chip for High Performance Computing with Distributed PCs

Konosuke Watanabe, Tomohiro Otsuka, Junichiro Tsuchiya, Hiroaki Hiroaki, Junji Yamamoto, Noboru Tanabe, Tomohiro Kudoh, Hideharu Amano

IEEE Transactions on Parallel and Distributed Systems （IEEE Computer Society）  18 （ 9 ） 1282-1295 - 1295 2007年09月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  1045-9219

　概要を見る

In this paper, "Martini," a network interface controller chip for our original network called RHiNET is described. Martini is designed to provide high-bandwidth and low-latency communication with small overhead. To obtain high performance communication, protected user-level zero-copy RDMA communication functions are completely implemented by a hardwired logic. Also, to reduce the communication latency efficiently, we have proposed PIO-based communication mechanisms called "On-the-fly (OTF)" and have implemented them on Martini. The evaluation results show that Martini connected to a 64bit/66MHz PCI-bus achieves 470MByte/s maximum bidirectional bandwidth and 1.74 μsec minimum latency on host-to-host memory copying. © 2007 IEEE.

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Improvement of Performances in Bilateral Teleoperation by Using FPGA

Ena Ishii, Hiroaki Nishi, Kouhei Ohnishi

IEEE Transactions on Industrial Electronics 54 （ 4 ） 1876-1884 2007年08月

研究論文（学術雑誌）, 単著, 査読有り

Collision Avoidance Method of Humanoid Robot With Arm Force

Eijiro Ohashi, Takahiro Aiko, Toshiaki Tsuji, Hiroaki Nishi, Kouhei Ohnishi

IEEE Transaction on Industrial Electronics （IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC）  54 （ 3 ） 1632-1641 - 1641 2007年08月

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  0278-0046

　概要を見る

This paper describes a collision avoidance method for a biped robot with an upper body. We propose a method wherein the robot stops in front of an obstacle by generating arm force. When the robot detects the obstacle by the arm tip, it should stop short of the obstacle to avoid crash. Hence, we propose trajectory planning in consideration of the pushing force of the arm. The arm force is controlled to be generated as a function of the distance from the robot body to the obstacle. The closer the robot approaches the obstacle, the larger the arm force becomes. As a result, the robot can stop by utilizing the arm force. In case the obstacle is unmovable, the robot can stop by exerting arm force. If it is movable, the robot can continue walking by pushing it. In this paper, the linear inverted pendulum mode (LIPM) and the idea of orbital energy are introduced, and then, we extend LIPM and orbital energy in consideration of the dynamics of the arm force. The extended orbital energy is utilized to discriminate whether the robot can stop or not and to modify the trajectory of the robot to avoid collision. © 2007 IEEE.

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Improvement of Performances in Bilateral Teleoperation by Using FPGA

Ena Ishii, Hiroaki Nishi, Kouhei Ohnishi

IEEE Transactions on Industrial Electronics 54 （ 4 ） 1876-1884 2007年08月

研究論文（学術雑誌）, 共著, 査読有り

伝搬遅延を考慮したシステム結合の一表現法

名取 賢治，西　宏章，大西　公平

電気学会論文誌D 産業応用部門誌 127 （ 6 ） 635-642 2007年06月

研究論文（学術雑誌）, 単著, 査読有り

FPGAを用いた多自由度バイラテラル鉗子ロボットシステムの構築

石井 恵那，桂 誠一郎，西　宏章，大西　公平

電気学会産業応用部門誌 （一般社団法人 電気学会）  127-D （ 5 ） 508-517 - 517 2007年05月

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  0913-6339

　概要を見る

In recent days, minimally invasive surgery by using endoscope has spread and robots that support endoscopic surgery are being focused on. However, existing surgery robots could not transmit information of tactile sensation to operators. To improve the safety of robotic surgery, it is required to transmit the tactile sensation to the operator. To attain that need, a teleoperation method called bilateral has developed and we have achieved to transmit keen tactile sensation with one degree-of-freedom forceps robots. In this paper, multi degrees-of-freedom bilateral forceps robot system will be developed to make surgery robot adaptable to actual situation of the surgery.<br>In bilateral teleoperation of multi degrees-of-freedom robots, environmental information of master and slave should be exchanged in common coordinates. In this paper, mode coordinates is used as common coordinates. Mode coordinates are closely related to the motion of the robot. Method to decouple the mechanical interference on mode coordinate is proposed. The paper also proposes a controller implemented on FPGA to achieve short processing time and hard-realtime control. As a result, multi-degrees-of freedom force feedback is attained.<br>The experimental results show the viability of the proposed method.

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An approach to velocity estimation using FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) （IEEE）     2349 - 2354 2007年

査読有り,  ISSN  1553-572X

　概要を見る

FPGAs are focused on recently as motion control processors. Sampling periods become shorter by using FPGAs, and it is expected that improvement of the performance of the motion control system. However in M method, which is the most generally used velocity estimation method, velocity resolution becomes low due to the short sampling period. This leads to a limitation of the performance, especially in acceleration control using a disturbance observer which requires accurate velocity information. There are several velocity estimation methods to improve the resolution. These methods require a dividing operation. From point of view of resource sharing and resource utilization of FPGAs, implementing divider is not desired. In this paper, velocity estimation which does not require any divider is proposed to improve the velocity resolution in the short sampling period system. The validity of the proposed method is demonstrated by simulation, and the proposed method is implemented into position control system based on the acceleration control in experiments. ©2007 IEEE.

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Bilateral control in multi DOF haptic surgical robotic system utilizing FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi, Toshikazu Kawai, Yasuhide Morikawa, Masaki Kitajima, Soji Ozawa, Toshiharu Furukawa

IEEE International Symposium on Industrial Electronics （IEEE）     3084 - 3089 2007年

査読有り

　概要を見る

Minimally invasive surgery is an important issue from the point of view of patients' Quality of Life (QoL). An endoscopic surgery is one of the minimally invasive surgeries. With the endoscopic surgery, pain could be less. This operation, however, has difficulty, and surgeons have to be well trained. To solve this problem, an endoscopic surgery system based on haptic teleoperation was proposed. The characteristic of the system is position and force information is transmitted bilaterally between master and slave robots. This means that a teleoperation with haptic information can be achieved, and surgeons can perform a telesurgery safely and smoothly. The system, however, does not have enough degrees of freedom for an actual operation. In this paper, a multi degrees of freedom endoscopic robotic system is proposed. This system has 6 degrees of freedom on each master and slave robot. A haptic control system implemented in the proposed system is based on acceleration control. Due to control in acceleration dimension, robust and ideal position and force control are able to be attained simultaneously. The control system requires a short sampling period for attainment of wide bandwidth to transmit keen force sensation. To ensure the short sampling period in a multi degrees of freedom system, this paper proposes the multi degrees of freedom tele-robotic system utilizing FPGA as a controller. Finally the validity of the proposed system is shown by experimental results. ©2007 IEEE.

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KNIVES: Network based demand and supply control system - Enhancement for network and environmental affinity -

Toshihiko Handa, Charlotte Roesener, Junichi Ichimura, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) （IEEE）  2   1171 - 1176 2007年

ISSN  1935-4576

　概要を見る

KNIVES (Keio University Network oriented Intelligent and Versatile Energy saving System) is an IT based system, designed for Japanese power grids, that supports efficient control and balanced power supply. As KNIVES focuses on the integration of a vast numbers of end-users, it provides the necessary scalability, reliability, and dynamic adaptability. The latest generation of KNIVES system (V2) provides a new hardware concept for a local control that reflects environmental affinity. KNIVES terminals use Internet communication and supports ZigBee based environment sensors. The implementations of this system and practical field tests are described in this paper. ©2007 IEEE.

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Position control using an FPGA based on multirate acceleration control

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi

Proceedings of the 2007 4th IEEE International Conference on Mechatronics, ICM 2007 （IEEE）     323 - 328 2007年

査読有り

　概要を見る

Acceleration control using a disturbance observer is a strategy of robust motion control. In the acceleration control, fast sampling rate is a key issue to improve the performance of robustness. By using FPGAs, faster sampling rates can be achieved than those using PCs. The sampling rates of the systems using FPGAs can be faster than the frequency of PWM wave. In that case, the performance of the acceleration control is not improved as expected. The frequency of the PWM wave becomes a performance limitation of the system. In this paper, a position control system based on acceleration control using multirate sampling method is implemented into an FPGA to overcome the limitations. In these multirate systems, the sampling rates of the system output and control calculations are faster than that of the system input. Experimental results show that the robustness of the system can be improved, even though the sampling rates of the system output and the control calculations are faster than the PWM frequency by using the multirate sampling method. ©2007 IEEE.

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ジッタバッファを用いたネットワークバイラテラル制御システム

加藤 敦，西 宏章，大西 公平

電気学会論文誌D 産業応用部門誌 （一般社団法人 電気学会）  126 （ 12 ） 1737-1738 - 1738 2006年12月

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  0913-6339

　概要を見る

Jitter is a technical issues of network bilateral control system. Hence, this paper proposed the jitter buffer method, which makes transmission delay constant. The validity of proposed system is confirmed by the experiments.

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Cache-based Network Processor Architecture: Evaluation with Real Network Traffic

Michitaka Okuno, Shinji Nishimura, Shinichi Ishida Hiroaki Nishi

Special Section on Novel Device Architectures and System-Integration Technologies, IEICE Transactions on Electronics （IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG）  E89-C （ 11 ） 1620-1628 - 1628 2006年11月

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  0916-8524

　概要を見る

A novel cache-based network processor (NP) architecture that can catch up with next generation 100-Gbps packet-processing throughput by exploiting a nature of network traffic is proposed, and the prototype is evaluated with real network traffic traces. This architecture consists of several small processing units (PUs) and a bit-stream manipulation hardware called a burst-stream path (BSP) that has a special cache mechanism called a process-learning cache (PLC) and a cache-miss handler (CMH). The PLC memorizes a packet-processing method with all table-lookup results, and applies it to subsequent packets that have the same information in their header. To avoid packet-processing blocking, the CMH handles cache-miss packets while registration processing is performed at the PLC. The combination of the PLC and CMH enables most packets to skip the execution at the PUs, which dissipate huge power in conventional NPs. We evaluated an FPGA-based prototype with real core network traffic traces of a WIDE backbone router. From the experimental results, we observed a special case where the packet of minimum size appeared in large quantities, and the cache-based NP was able to achieve 100 throughput with only the 10-throughput PUs due to the existence of very high temporal locality of network traffic. From the whole results, the cache-based NP would be able to achieve 100-Gbps throughput by using 10- to 40-Gbps throughput PUs. The power consumption of the cache-based NP, which consists of 40-Gbps throughput PUs, is estimated to be only 44.7 that of a conventional NP. Copyright © 2006 The Institute of Electronics, Information and Communication Engineers.

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A Controller Design Method of Decentralized Control System

Toshiaki Tsuji, Hiroaki Nishi and Kouhei Ohnishi

IEEJ Trans. On Industry Applications 126-D （ 5 ） 630-638 2006年05月

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  0913-6339

　概要を見る

Decentralized control is a promising method with many advantages while an effective design method for it is desired. Design in conventional methods is complicated because the correspondence between a system role and its controllers is unclear. To solve this problem, we have proposed the idea of "functionality" for a bilateral control system. The idea is to divide the system role into minimum components. The design method based on this idea is clear since controllers correspond to respective functions. Furthermore, the design method is simple since each function is a minimum component. This study expands the idea of the functionality to design of decentralized control systems. Subsystems are constructed based on functions. Functions for normal operation and for exception handling are treated in a unified manner. The system can automatically sustain important functions by a priority order of functions. This method realizes simple and explicit controller design for a decentralized control system with exception handling. Simulation and experimental results show the flexibility, fault tolerance and expandability of the decentralized system.

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A Controller Design Method of Bilateral Control System

Toshiaki Tsuji, Kenji Natori, Hiroaki Nishi, Kouhei Ohnishi

European Power Electronics and Drives Journal (EPE Journal) （TAYLOR & FRANCIS LTD）  14 （ 2 ） 22-28 - 27 2006年05月

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  0939-8368

　概要を見る

Haptic sense is indispensable for skillful operation in a telerobotic system. Bilateral control attracts considerable interest because it transfers the haptic sense to a remote place. Although it is simply composed of two manipulators, its design is complicated. This study proposes an idea that provides a new framework on design of a bilateral control system. The idea is to design the bilateral control system based on a "function", a minimum component of a system role. It enables simple and explicit design for various tasks. The features of the proposed method provide a way to design an adjustable system. Experimental results show the validity of the proposed method.

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100-Gb/s Physical-layer Architecture for Next-Generation Ethernet

Hidehiro Toyoda, Shinji Nishimura, Michitaka Okuno, Kouji Fukuda, Kouji Nakahara, and Hiroaki Nishi

IEICE Transactions on Communications （IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG）  E89-B （ 3 ） 696-703 - 702 2006年03月

研究論文（学術雑誌）, 単著, 査読有り,  ISSN  0916-8516

　概要を見る

A high-speed physical-layer architecture for Ethernet is described that supports 100-Gb/s throughput and 40-km transmission, making it well suited for next-generation metro-area and intrabuilding networks. Its links comprise 12 × 10-Gb/s synchronized parallel optical lanes. Ethernet data frames are transmitted by coarse wavelength division multiplexing link and bundled optical fibers. Ten of the lanes convey 640-bit data synchronously (64 bits × 10 lanes). One conveys forward error correction code ((132 b, 140 b) Hamming code), providing highly reliable (BER < 10-12) data transmission, and the other conveys parity data, enabling fault-lane recovery. A newly developed 64B/66B code-sequence-based deskewing mechanism is used that provides low-latency compensation for the lane-to-lane skew, which is less than 88 ns. Testing of this physical-layer architecture in a field programmable gate array circuit demonstrated that it can provide 100-Gb/s data communication with a 590 k gate circuit, which is small enough for implementation in a single LSI circuit. Copyright © 2006 The Institute of Electronics, Information and Communication Engineers.

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マルチレートサンプリング手法を用いた加速度制御系の実現

水落　麻里子，辻　俊明，大西　公平，西　宏章

電気学会論文誌産業応用部門誌 126 （ 3 ） 261-268 2006年03月

研究論文（学術雑誌）, 単著, 査読有り

ネットワークトラフィックの時間的局所性を利用したブロードバンドネットワーク向けキャッシュ型パケット処理技術

奥野 通貴, 西村 信治, 石田 慎一, 西 宏章

情報処理学会論文誌ブロードバンド・ユビキタス・ネットワークとその応用特集号 （一般社団法人情報処理学会）  47 （ 2 ） 346-353 - 354 2006年02月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  1882-7764

　概要を見る

急速なネットワークのブロードバンド化にともない，2007 年以降頃のバックボーンルータは回線あたり現在比10 倍の100Gbps（Gigabit per second）のパケット処理スループットを大幅な消費電力の増加なしで実現することが求められる．筆者らは，ネットワークトラフィックで短時間に同一のヘッダを持つパケットが大量に出現することを利用するキャッシュ型パケット処理技術を提案した．本技術を用いるパケット処理エンジン（PPE）は，消費電力増加の原因となる内蔵プロセッサを増加させず，専用ハードウェア部にパThe cache-based packet-processing enginge (PPE) that consists of Process-Learning Cache (PLC) and Cache-Miss Handler (CMH) is proposed to achieve 100-Gbps (Gigabit per second) wire-rate throughput which would be needed for backbone routers in 2007 or late

Discussion of aspects in energy management with demand response system KNIVES

S. Ishida, C. Roesener, H. Nishi, J. Ichimura

IEEE International Conference on Emerging Technologies and Factory Automation, ETFA （IEEE）     465 - 468 2006年

　概要を見る

This paper describes with the design of a communication network necessary for Demand Response systems adapted to the requirements of the Japanese power grid. Based on KNIVES controllers and network devices an exemplary redundant hierarchical tree structure is proposed to meet high demands on reliability, scalability and dynamic adaptability in order to be capable to secure the wholesale competition. Therefore essential information for energy management has to be secured, managed, processed and delivered. Using Internet for communication, the network has to guarantee reliability facing a high variety of network availability. This approach focuses on redundant data management combined with non local control loops of the power supply system, which shall guarantee a functional safe and high-performance microglia. © 2006 IEEE.

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Energy assessment of cogeneration and air conditioning system on Keio University Shonan Fujisawa Campus

Atsushi Mise, Hitoaki Nishi, Haruki Sato

2006 IEEE International Conference on Industrial Informatics, INDIN'06    387 - 392 2006年

　概要を見る

Conservation of energy has become a major concern all over the world. Especially in the domestic area, public buildings, and office buildings, energy supply systems have to be optimized swiftly balancing with the time-dependent energy demand. This paper discusses the exemplary energy assessment of the cogeneration and air-conditioning system on Keio University Shonan Fujisawa Campus with approximately 5,000 students and 200 faculty members. The purpose of the cogeneration system consisting of prime mover and exhaust heat recovery equipment is a conlribution to energy conservation. Exhaust heal of lhe prime mover can be reutilized in form of heated or chilled water by the exhaust heat recovery equipment. Optimized reutilization of exhaust heat shall bring the main benefit for energy conservation. Therefore, the effectiveness of the cogeneration system has been evaluated based on collected annual data of energy consumption on the campus. Furthermore, curtailment of air-conditioning systems during peak load caused by the congestion of the grid power has been examined. In order to optimize the energy management under these conditions, the forecast of power consumption has been discussed, and the relation of power consumption to air temperature has been examined. © 2006 IEEE.

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Internet-based hybrid demand control system for Japanese power grid

C. Roesener, S. Ishida, J. Ichimura, H. Nishi

IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS    395 - 400 2006年

　概要を見る

Worldwide the demand on a higher level of automatic control of power systems rises to comply with system objectives of reliability, efficiency, cost minimization as well as emission requirements. With the transition of the power systems towards a more volatile on-site generation based on renewable resources, a higher degree of flexibility in energy consumption for reduced system congestion is evident. This paper presents a real-time information system for active control of the demand side in Japanese power grids. The proposed system allows local data processing of environmental and consumption data to schedule and curtail loads of shops, small and medium size enterprises. The concept comprises specialized control hardware for end-use supervision, local and internet based server architecture and control methods for global energy management. © 2006 IEEE.

Improvement of performance in bilateral teleoperation by using FPGA

Ena Ishii, Hiroaki Nishi, Kouhei Ohnishi

International Workshop on Advanced Motion Control, AMC （IEEE）  2006   317 - 322 2006年

査読有り

　概要を見る

Bilateral teleoperation has been needed in many scenes such as space activities or undersea, work on a atomic power plant and minimally invasive surgery, etc. In bilateral teleoperation, transfer of keen tactile sense as if the operator directly touch the environment without using the robot is required. Wide frequency bandwidth of force sensing is required to achieve transfer of a keen tactile sensation. Bilateral controller based on acceleration control with disturbance observer is available to achieve transfer of a keen tactile sensation. The frequency bandwidth of force sensing is determined by cut-off frequency of low-pass filter used in disturbance observer. The cut-off frequency is in inverse proportion to a sampling period. Therefore, shortening of the sampling period improves performance of bilateral teleoperation. In this paper, bilateral teleoperation system by using FPGA(Field Programmable Gate Array) is introduced. FPGA is a LSI that user can design its internal logic. When motion controller is implemented on FPGA, it operates faster than that implemented in a PC(Personal computer) with RTOS(Real Time Operating System). The sampling period is shortened from 100/its to 10μs by using FPGA. © 2006 IEEE.

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Implementation of Internet based demand controlling system

S. Ishida, C. Roesener, J. Ichimura, H. Nishi

2006 IEEE International Conference on Industrial Informatics, INDIN'06    381 - 386 2006年

　概要を見る

Due to liberalization processes initiated on Japan's power market since 2000, a significant higher congestion on the power grid is expected entailing a higher vulnerability to shortages. With increasing aspirations on power supply security, an interaction with the demand side has become inevitable to reduce the congestion without the need for new generation or transmission capacities. Attaining efficiency close to the optimum in curtailing and rescheduling loads, the fast automatic processing of essential information affecting the performance of the power grid is crucial. This approach shows a solution for hybrid demand control integrating a vast number of small and medium sized enterprises for centralized load management based on locally collected environmental data. The hardware and software of this system has been prototyped and evaluated. Evaluation tests show the capability of this system to deliver the necessary infrastructure necessary for demand control. © 2006 IEEE.

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Evaluation of cache base network processor by using real backbone network trace

Shinichi Ishida, Michitaka Okuno, Hiroaki Nishi

2006 Workshop on High Performance Switching and Routing, HPSR 2006 （IEEE）     49 - 54 2006年

査読有り

　概要を見る

In this paper a novel cache-based packet-processing-engine (PPE) architecture that achieves high packet-processing throughput with low-power consumption is proposed and evaluated. As network packets of the same header information appear repeatedly in a short time, a special cache, the so called header-learning cache(HLC), memorizes the packet-processing method and enables most packets to skip the execution at the processing units array. The implementation of the cache-based PPE architecture, P-Gear, was designed. Real backbone network trace was used to evaluate the performance of it. This P-Gear can achieve over 80% cache hit rate using 4K/32K entry for access/core networks. Compared to conventional PPE, P-Gear can achieve 100-Gbps (gigabit per second) packet-processing throughput with only 36.5% of the die size and 32.6% of the power consumption required by the conventional PPE. © 2006 IEEE.

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A 100-Gb-Ethernet subsystem for next-generation metro-area network

Hidehiro Toyoda, Shinji Nishimura, Michitaka Okuno, Ryouji Yamaoka, Hiroaki Nishi

IEEE International Conference on Communications （IEEE）  2   1036 - 1042 2005年

ISSN  0536-1486

　概要を見る

An ultra high-speed Ethernet subsystem, which realizes 100-Gb/s throughput and transmission up to 40 km, is examined for next-generation metro-area networks. A parallel link of 12 10-Gb/s synchronized parallel optical lanes is proposed. The 10 optical lanes are used to transmit 10-bit parallel data. The one of redundant lanes transmits a forward error correction code ((132b, 140b) Hamming code) to achieve highly-reliable (BER < 10-12) data transmission, and the other lane transmits a parity data used for the fault-lane recovery. Here, a 64B/66B code-sequence-based de-skewing mechanism is proposed, and its effectiveness to realize low-latency compensation of the inter-lane skew (< 80 ns) is shown. We have implemented the 100-Gb-Ethernet interface architectures into FPGA circuits, and confirmed the performance of 100 Gb/s data communication with compact 385-kgates circuit size, which is practically small for implementation in a single LSI circuit. © 2005 IEEE.

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Bilateral teleoperation based on modal system design

Ena Ishii, Seiichiro Katsura, Hiroaki Nishi, Kouhei Ohnishi

IEEE International Symposium on Industrial Electronics IV   1527 - 1532 2005年

査読有り

　概要を見る

Technology for teleoperation has been needed in many scenes. Especially in robotic surgery, It is required that to transmit the tactile sensation to the operator. To attain that need, teleoperation method called bilateral has developed. Bilateral means transmit information each other. Environmental information is transmitted both from master to slave and from slave to master in bilateral teleoperation. In bilateral teleoperation, environmental information of master and slave should be exchanged in common coordinates. It is difficult to define a common coordinates in different structured bilateral teleoperation. Mode based control for bilateral teleoperation is proposed in this paper. Coordinates based on geometric mode is used to common coordinates to exchange the environmental information between master robot and slave robot. Geometric environmental mode is quarried by quarry matrix and hypothetical axes bilateral controller based on acceleration control is applied to hypothetical mode motors. Hypothetical mode master motor and mode slave motor are transformed to mode common motor and mode differential motor. Force servo controller is applied to mode common motor and position regulator is applied to mode differential motor. Viability of proposed method is shown in experimental result. ©2005 IEEE.

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A velocity measurement method for acceleration control

Toshiaki Tsuji, Mariko Mizuochi, Hiroaki Nishi, Kouhei Ohnishi

IECON Proceedings (Industrial Electronics Conference) 2005   1943 - 1948 2005年

査読有り

　概要を見る

This paper proposes a novel method of velocity measurement for motor drives with optical encoders. Acceleration control is indispensable for advanced motion control while it requires accurate velocity information. Although many methods on velocity measurement have been proposed, accurate measurement was not achieved in a high-speed range. We therefore propose " synchronousmeasurement method (S method)" that measures the velocity synchronized with alteration of pulse numbers. Accurate velocity measurement is achieved in all speed ranges with this method. Furthermore, other estimation methods are applicable in addition since the method does not require any model of a control object. Simulation and experimental results verify the validity of the proposed method. © 2005 IEEE.

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A packet forwarding layer for DIMMnet and its hardware implementation

Yoshihiro Hamada, Hiroaki Nishi, Akira Kitamura, Noboru Tanabe, Hideharu Amano, Hironori Nakajo

Proceedings of the 2005 International Conference on Parallel and Distributed Processing Techniques and Applications, PDPTA'05 （CSREA Press）  2   461 - 467 2005年

　概要を見る

DIMMnet-1 is a high-performance network interface for a PC cluster system. It uses memory bus for IO bus to relax a bottleneck of networks. Moreover, a PC memory bus is spread bandwidth earliest in a PC, the DIMMnet-1 can reorganize a NIC according to spreading bandwidth of a communication link. However, the NIC that use a parallel transmission lacks a scalability of a bandwidth of a communication link. To resolve this problem, we developed new NICs : DIMMnet-1/bDais and DIMMnet-2. We employ a high-speed serial transmission on these NICs. Therefore we have to expand the DIMMnet network protocol. Now we have been developing new DIMMnet network protocol by two parts. The One is the CoreLogic which includes communication primitives. In this paper, we describe the rest of that which is the InfiniSWIF that includes functions of packet forwarding. And we propose the Concurrent Datagram communication service which is implemented in the InfiniSWIF and gives reliability and scalability for the DIMMnet network protocol.

SoC architecture synthesis methodology based on high-level IPs

Michiaki Muraoka, Hiroaki Nishi, Rafael K. Morizawa, Hideaki Yokota, Yoichi Onishi

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E87-A （ 12 ） 3057 - 3067 2004年12月

ISSN  0916-8508

　概要を見る

We propose a sophisticated synthesis methodology for SoC (System-on-Chip) architectures from the system level specification based on reusable high-level IPs named as Virtual Cores (VCores), in this paper. This synthesis methodology generates an initial architecture that consists of a CPU, buses, IPs, peripherals, I/Os and an RTOS (Real Time Operating System), as well as making tradeoffs to the architecture, between hardware and software on assigned software VCores and hardware VCores. The results of an architecture level design experiment, using the proposed methodology, shows that the partial automation of the architecture synthesis process, allied with design reuse, accelerates the architecture design, therefore, reducing the time required to design an architecture of SoC.

Autonomous Decentralized Control for Formation of Multiple Mobile-Robots Considering Ability of Robot

Hiroamasa Takahashi, Hiroaki Nishi, Kouhei Ohnishi

IEEE Transactions on Industrial Electronics （IEEE）  Vol. 51 （ 6 ） 1272- 1279 - 1279 2004年05月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  0278-0046

　概要を見る

The purpose of this study is to control multiple mobile robots in formation considering the ability of a robot using the "Leader-Following" strategy. There are three features of this study. First, a performance index that shows mobile robot ability is quantified. Specifically, maximum acceleration and maximum velocity of a robot are defined by maximum admissible rotation and maximum continuous torque of a motor. The performance index is quantified from arrival time on the destination using these parameters. Second, a new controller is proposed based on the performance index, so that robots can be controlled according to robot ability. Third, a compliance controller using a virtual repulsion is suggested in this paper, so that each robot can avoid collision. Finally, simulation and experiments are done in a real-time system using RT-Messenger. RT-Messenger allows robots to transmit information regarding their positions to each other in real time. These results shows the validity of the proposed method. © 2004 IEEE.

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Design methodology for SoC architectures based on reusable virtual cores

Michiaki Muraoka, Hiroaki Nishi, Rafael K. Morizawa, Hideaki Yokota, Hideyuki Hamada

Proceedings of the Asia and South Pacific Design Automation Conference, ASP-DAC （IEEE Computer Society）     256 - 262 2004年

　概要を見る

The design reuse methodology, which has been developed at the VCDS Project, is a SoC design methodology to reduce the SoC design time using high level design intellectual properties named as Virtual Cores (VCores). In this paper, we propose the VCore based design methodology to synthesize the SoC architecture from the system level specification. This synthesis methodology generates an initial architecture that consists of a CPU, buses, I/Os peripherals, and RTOS (Real Time Operating System), and makes tradeoffs between hardware and software on assigned software VCores and hardware VCores models to the architecture. The results of an architecture level design experiment using the proposed methodology shows that the partial automation of the communication refinement process, allied with design reuse, accelerates the architecture synthesis, thus reducing the design time required to design an architecture.

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Signal Transmission and Coding Architecture for Next Generation Ethernet

西 宏章

IEICE Transaction on Information and Systems E-86-D （ 11 ）  2003年11月

研究論文（学術雑誌）, 共著

Signal Transmission and Coding Architecture for Next Generation Ethernet

Hidehiro Toyoda, Hiroaki Nishi, Shinji Nishimura, Hisaaki Kanai, Katsuyoshi Harasawa

IEICE Journal Special Issue on New Technologies in the Internet and their Architecture E-86-D （ 11 ） 2317-2324 2003年11月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り

Low-Power Network-Packet-Processing Architecture Using Process Learning Cache for High-end Backbone Router

Michitaka Okuno, Shin-ichi Ishida, Hiroaki Nishi

IEICE Transaction on Electronics(Special Section on Low-Power LSI, Low-Power IP and Low Power Devices) （Institute of Electronics, Information and Communication, Engineers, IEICE）  E88-C （ 4 ） 536-543 - 543 2003年10月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り,  ISSN  0916-8524

　概要を見る

A novel cache-based packet-processing-engine (PPE) architecture that achieves low-power consumption and high packet-processing throughput by exploiting the nature of network traffic is proposed. This architecture consists of a processing-unit array and a bit-stream manipulation path called a burst stream path (BSP) that has a special cache mechanism called a process-learning cache (PLC). Network packets, which have the same information in their header, appear repeatedly over a short time. By exploiting that nature, the PLC memorizes the packet-processing method with all results (i.e., table lookups), and applies it to other packets. The PLC enables most packets to skip the execution at the processing-unit array, which consumes high power. As a practical implementation of the cache-based PPE architecture, P-Gear was designed. In particular, P-Gear was compared with a conventional PPE in terms of silicon die size and power consumption. According to this comparison, in the case of current 0.13-μm CMOS process technology, P-Gear can achieve 100-Gbps (gigabit per second) packet-processing throughput with only 36.5% of the die size and 32.8% of the power consumption required by the conventional PPE. Configurations of both architectures for the 1- to 100-Gbps throughput range were also analyzed. In the throughput range of 10-Gbps or more, P-Gear can achieve the target throughput in a smaller die size than the conventional PPE. And for the whole throughput range, P-Gear can achieve a target throughput at lower power than the conventional PPE. Copyright © 2005 The Institute of Electronics, Information and Communication Engineers.

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The Architecture and Evaluation of 3rd-generation RHiNET Switch for High-performance Parallel Computing

Hiroaki Nishi, Shinji Nishimura, Katsuyoshi Harasawa, Tomohiro Kudoh, Hideharu Amano

Special Issue on Development of Advanced Computer Systems E-86-D （ 10 ） 1987-1995 2003年10月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り

Architecture and Evaluation of a Third-Generation RHiNET Switch for High-Performance Parallel Computing

Hiroaki Nishi, Shinji Nishimura, Katsuyoshi Harasawa, Tomohiro Kudoh, Hideharu Amano

IEICE Transactions on Information and Systems E86-D （ 10 ） 1987 - 1995 2003年10月

ISSN  0916-8532

　概要を見る

RHiNET-3/SW is the third-generation switch used in the RHiNET-3 system. It provides both low-latency processing and flexible connection due to its use of a credit-based flow-control mechanism, topology-free routing, and deadlock-free routing. The aggregate throughput of RHiNET-3/SW is 80 Gbps, and the latency is 140 ns. RHiNET-3/SW also provides a hop-by-hop retransmission mechanism. Simulation demonstrated that the effective throughput at a node in a 64-node torus RHiNET-3 system is equivalent to the effective throughput of a 64-bit 33-MHz PCI bus and that the performance of RHiNET-3/SW almost equals or exceeds the best performance of RHiNET-2/SW, the second-generation switch. Although credit-based flow control requires 26% more gates than rate-based flow control to manage the virtual channels (VCs), it requires less VC memory than rate-based flow control. Moreover, its use in a network system reduces latency and increases the maximum throughput compared to rate-based flow control.

LAN領域での高性能並列処理に適したネットワークスイッチ用ASIC

西 宏章，西村 信治，工藤 知宏，天野 英晴

電子情報通信学会論文誌システムＬＳＩのための先進アーキテクチャ特集号C （一般社団法人電子情報通信学会）  J86-C （ 8 ） 836-844 - 844 2003年08月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り,  ISSN  1345-2827

　概要を見る

本論文では,LAN領域で低遅延かつ高信頼な計算環境を実現するRHiNETシステムについて,このシステムで用いるネットワークスイッチRHiNET-3/SWに搭載するスイッチASIC,及びスキュー調整ASICについて述べる.スイッチASICは小さい処理遅延,高い柔軟性,高い信頼性を兼ね備える.また,スキュー調整ASICは,1kmの伝送路で発生するスキューを効率良く調整するため新しい環状スキュー調整符号を用いる.

Virtual core based synthesis of SoC architectures

Hiroaki Nishi, Michiaki Muraoka, Rafael K. Morizawa, Hideaki Yokota, Hideyuki Hamada

IEEE International Symposium on Semiconductor Manufacturing Conference Proceedings 1   35 - 40 2003年

ISSN  1523-553X

　概要を見る

© 2003 IEEE. The reuse of high-level design intellectual properties is indispensable to reduce SoC design time. It has been difficult for SoC designers to design and compare two or more SoC architectures in a given product design time. In this paper, we present a synthesis methodology of SoC architectures using Virtual Cores (VCores) to perform architectural explorations in a short period. The proposed synthesis methodology generates an initial architecture, which consists of a CPU, buses, I/Os. etc., and makes tradeoffs between hardware and software on mapped software VCores and hardware VCores models. The authors show the usefulness of me proposed method from the results of an architecture level design experiment.

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VCore-based design methodology.

Michiaki Muraoka, Hideyuki Hamada, Hiroaki Nishi, Toshihiko Tada, Yoichi Onishi, Toshinori Hosokawa, Kenji Yoshida

Proceedings of the 2003 Asia and South Pacific Design Automation Conference(ASP-DAC) （ACM）     441 - 445 2003年

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Performance Evaluation of a Prototype of RHiNET-2: A Network-based Distributed Parallel Computing System

Tomohiro Otsuka, Konosuke Watanabe, Jun ichiro Tsuchiya, Hiroshi Harada, Junji Yamamoto, Hiroaki Nishi, Tomohiro Kudoh, Hideharu Amano

IASTED International Multi-Conference on Applied Informatics （IASTED/ACTA Press）  21   738 - 743 2003年

　概要を見る

RHiNET is a network which has advantages of both Local Area Networks (LANs) and System Area Networks (SANs). In this paper, preliminary performance evaluation of RHiNET-2 on a small prototype system is described. We use two benchmark applications, IS from the NAS Parallel Benchmarks and LU from the SPLASH-2 Benchmark Suite, on the SCore Cluster System Software. The performance is improved 3.12 times in IS and 3.64 times in LU on a system with four nodes.

Synthesis for SoC architecture using VCores

H. Nishi, M. Muraoka, R. K. Morizawa, H. Yokota, H. Hamada

Proceedings of the Asia and South Pacific Design Automation Conference, ASP-DAC （ACM）  2003-January   446 - 452 2003年

　概要を見る

© 2003 IEEE. In this paper, we propose a novel architecture synthesis method for SoCs using VCores (virtual cores). VCores are reusable and configurable high-level descriptions. An initial SoC architecture, which consists of a CPU, buses, and peripherals, is generated, based on an architecture template. The hardware and software tradeoff is possible on the architecture model after assignment of software VCores or hardware VCores. The assignment is based on the results of the architecture's performance estimation. We present a prototype of the synthesis for SoC architecture using VCores and an architecture level design experiment using this prototype.

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Performance evaluation of RHiNET 2/NI: A network interface for distributed parallel computing systems

Konosuke Watanabe, Tomohiro Otsuka, Jun Ichiro Tsuchiya, Hideharu Amano, Hiroshi Harada, Junji Yamamoto, Hiroaki Nishi, Tomohiro Kudoh

Proceedings - CCGrid 2003: 3rd IEEE/ACM International Symposium on Cluster Computing and the Grid （IEEE Computer Society）     318 - 325 2003年

査読有り

　概要を見る

RHiNET-2/NI is a network interface for a parallel and distributed computing system with network connected PCs. The core of the network interface is an ASIC network controller chip Martini, which provides low-latency and large-bandwidth communication. Evaluation results show that it achieves almost full bandwidth of the 66MHz/64bit PCI bus, which is much larger than that of Myrinet-2000. The performance of a small prototype parallel system achieves almost linear speed up. © 2003 IEEE.

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高性能計算をサポートするネットワークインタフェース用コントローラチップ Martini

山本 淳二，渡邊 幸之介，土屋 潤一郎，原田 浩，今城 英樹，寺川 博昭，西 宏章，田邊 昇，上嶋 利明，工藤 知宏，天野 英晴

情報処理学会論文誌 （一般社団法人情報処理学会）  43 （ SIG6 ） 122-133 - 133 2002年09月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り,  ISSN  0387-5806

　概要を見る

ユーザレベル・ゼロコピー通信を用いることで低レイテンシ・広バンド幅な通信を提供するネットワークRHiNETのネットワークインタフェースコントローラMartiniについて述べる.Martiniでは基本のRDMA機能をすべてハードワイヤード処理することで,低レイテンシ・広バンド幅のRHiNETネットワークを最大限利用する.その一方で内部にプロセッサを持つことで複雑な処理についても柔軟に対処できる構成となっている.

A network switch for supporting high-performance parallel processing by computers distributed in local areas

Hiroaki Nishi, Koji Tasho, Tomohiro Kudoh, Hideharu Amano

Systems and Computers in Japan 32 （ 14 ） 24 - 33 2001年12月

査読有り,  ISSN  0882-1666

　概要を見る

The authors have developed a communications architecture called RHiNET that is capable of high-performance parallel processing by interconnecting PCs and WSs. RHiNET uses not only computers concentrated in one place but also computers used for daily business within buildings and within floors for parallel processing. Networks used by RHiNET should have high effective bandwidths and small latencies for high-efficiency computing, as well as link lengths for connecting the computers within buildings and floors and a free topology. The former requirements are not satisfied sufficiently by the conventional LANs, while the latter is not satisfied by SANs which are used in cluster systems. RHiNET satisfies both conditions by using a switch having a large memory capacity. In this paper, the architecture and implementation of the RHiNET/SW1 switch used by RHiNET networks are discussed. A scheme called virtual cache is used in RHiNET/SW1 such that a large-capacity packet buffer is installed by SRAM outside the switch ASIC. In addition, the performance of the switch is evaluated by a simulator. © 2001 Scripta Technica, Syst. Comp. Jpn.

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RHiNET-2/SW: 並列光インタコネクションを搭載した並列計算機システム用高速ネットワークスイッチ

Shinji Nishimura, Tomohiro Kudoh, Hiroaki Nishi, Junji Yamamoto, Katsuyoshi Harasawa, Shuji Fukuda, Yasutaka Shikichi, and Shigeto Akutsu

電子情報通信学会論文誌. C, エレクトロニクス （一般社団法人電子情報通信学会）  85 （ 6 ） 756-765 - 10 2001年09月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り,  ISSN  8756-663X

　概要を見る

分散配置したPC間を光インタコネクションで接続し, 大容量並列処理を可能とする計算機システムRHiNET-2に搭載する高速ネットワークスイッチRHiNET-2/SWを開発した.RHiNET-2/SWは, スイッチLSIと並列同期光インタコネクションモジュール(800Mbit/s×12ch)送受8対をボード上に高密度実装し, 単体で64Gbit/sの大容量スイッチング処理を実現する(8Gbit/s×8ポート).今回, ビットエラーレート測定により, 10^<-11>以下(近似計算によると10^<-20>台)の信頼性を確認すると共に, 本スイッチ5台とPCノード16台を接続して計算システムを構成し, 計算機システムとしての安定動作に成功した.本結果により, 並列計算機システムにおいて大容量かつ柔軟なネットワークを実現する光インタコネクションの実用性を実証した.

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RHiNET-2/SW: 並列光インタコネクションを搭載した並列計算機システム用高速ネットワークスイッチ，

西村 信治，工藤 知宏，西 宏章，山本 淳二，原澤 克嘉，福田 周司，敷地 泰卓，圷 重人

電子情報通信学会論文誌 J84-C （ 9 ） 756-765 2001年09月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り

Recursive Diagonal Torus: An Interconnection Network for Massively Parallel Computers

Yulu Yang, Akira Funahashi, Akiya Jouraku, Hiroaki Nishi, Hideharu Amano, and Toshinori Sueyoshi

IEEE TRANSACTIONS on Parallel And Distributed Systems （IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC）  12 （ 7 ） 701-715 - 715 2001年07月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り,  ISSN  1045-9219

　概要を見る

Recursive Diagonal Torus (RDT), a class of interconnection network is proposed for massively parallel computers with up to 2 16 nodes. By making the best use of a recursively structured diagonal mesh (torus) connection, the RDT has a smaller diameter (e.g., it is 11 for 2 16 nodes) with a smaller number of links per node (i.e., 8 links per node) than those of the hypercube, A simple routing algorithm, called vector routing, which is near-optimal and easy to implement is also proposed. Although the congestion on upper rank tori sometimes degrades the performance under the random traffic, the RDT provides much better performance than that of a 2D/3D torus in most cases and, under hot spot traffic, the RDT provides much better performance than that of a 2D/3D/4D torus. The RDT router chip which provides a message multicast for maintaining cache consistency is available. Using the 0.5μm BiCMOS SOG technology, versatile functions, including hierarchical multicasting, combining acknowledge packets, shooting down/restart mechanism, and time-out/setup mechanisms, work at a 60MHz clock rate.

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Optical interconnection as an IP macro of a CMOS library

T. Yoshikawa, I. Hatakeyama, K. Miyoshi, K. Kurata, J. Sasaki, N. Kami, T. Sugimoto, M. Fukaishi, K. Nakamura, K. Tanaka, H. Nishi, T. Kudoh

Proceedings - Symposium on the High Performance Interconnects, Hot Interconnects （IEEE Computer Society）  2001-January   31 - 35 2001年

ISSN  1550-4794

　概要を見る

© 2001 IEEE. With the aim of producing a switch LSI with several-hundred-Gb/s-class throughput, we first developed LAN-LSIs with 10-Gb/s-class optical input/output (I/O) buffer. The optical I/O buffer was supplied as a set consisting of an optical-electrical package, soft or hard macros of the optical interface, and library files for a targeted CMOS technology. Using such library files, system LSI designers can implement an optical interface in their chips in a conventional design manner.

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RHiNET-3/SW: An 80-Gbit/s high-speed network switch for distributed parallel computing

S. Nishimura, T. Kudoh, H. Nishi, J. Yamamoto, R. Ueno, K. Harasawa, S. Fukuda, Y. Shikichi, S. Akutsu, K. Tasho, H. Amano

Proceedings - Symposium on the High Performance Interconnects, Hot Interconnects （IEEE Computer Society）  2001-January   119 - 123 2001年

ISSN  1550-4794

　概要を見る

© 2001 IEEE. We have developed a prototype network switch, RHiNET-3/SW, for a RHiNET high-performance distributed parallel computing environment. It has eight I/O ports and each port provides high-speed, bi-directional 10-Gbit/s-per-port parallel optical data transmission in a distance of over 300 m. The aggregate throughput is 80 Gbit/s per board. A switch consists of a one-chip CMOS ASIC 8x8 switch LSI (SW-LSI; a 784-pin BGA package), four deskew LSIs, and eight pairs of 1.25-Gbit/s x 12-channel optical interconnection modules on a single board. The switch uses a hop-by-hop retransmission mechanism and credit-based flow control to provide reliable and long-transmission-distance data communication. The deskew LSI has a skew compensation function for 10-bit parallel data channels and an 8B10B encoder/decoder. Its optical transmitter modules use an 850-nm VCSEL and a 12-channel MMF (multi-mode fiber) ribbon. RHiNET-3/SW enables high-throughput. Long-distance and flexible-flow-control network communication by means of distributed parallel computing using commercial PCs.

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ハイパフォーマンスルータアーキテクチャに関する研究

西 宏章

慶應義塾大学大学院理工学研究科 博士学位論文 2000年12月

研究論文（その他学術会議資料等）, 単著

64-Gb/s highly reliable network switch (RHiNET-2/SW) using parallel optical interconnection

Shinji Nishimura, Tomohiro Kudoh, Hiroaki Nishi, Junji Yamamoto, Katsuyoshi Harasawa, Nobuhiro Matsudaira, Shigeto Akutsu, Hideharu Amano

Journal of Lightwave Technology 18 （ 12 ） 1620 - 1627 2000年12月

査読有り,  ISSN  0733-8724

　概要を見る

RHiNET-2/SW is a network switch that enables high-performance optical network-based parallel computing system in a distributed environment. The switch used in such a computing system must provide high-speed, low-latency packet switching with high reliability. Our switch allows high-speed 8-Gb/s/port optical data transmission over a distance of up to 100 m, and the aggregate throughput is 64 Gb/s. In RHiNET-2/SW, eight pairs of 800 -Mb/s × 12-channel optical interconnection modules and a one-chip CMOS ASIC switch LSI (a 784-pin BGA package) are mounted on a single compact board. To enable high-performance parallel computing, this switch must provide high-speed, highly reliable node-to-node data transmission. To evaluate the reliability of the switch, we measured the bit error rate (BER) and skew between the data channels. The BER of the signal transmission through one I/O port was better than 10-11 at a data rate of 800 Mb/s × 10 b with a large timing-budget margin (870 ps) and skew of less than 140 ps. This shows that RHiNET-2/SW can provide high-throughput, highly reliable optical data transmission between the nodes of a network-based parallel computing system.

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64-Gbit/s highly reliable network switch (RHiNET-2/SW) using parallel optical interconnection

Shinji Nishimura, Tomohiro Kudoh, Hiroaki Nishi, Junji Yamamoto, Katsuyoshi Harasawa, Nobuhiro Matsudaira, Shigeto Akutsu, and Hideharu Amano

IEEE journal of lightwave technology (Special issue on Optical Networks) 18 （ 12 ） 1620-1627 2000年11月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り

A high-speed, highly-reliable network switch for parallel computing system using optical interconnection

Shinji Nishimura, Tomohiro Kudoh, Hiroaki Nishi, Koji Tasho, Katsuyoshi Harasawa, Shigeto Akutsu, Shuji Fukuda, and Yasutaka Shikichi

The IEICE Transaction on Electronics (Special Issue on Optical Interconnects/ Optical Signal Processing) E84 （ 9 ） 756-765 - 294 2000年09月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り,  ISSN  0916-8524

　概要を見る

RHiNET-2/SW is a network switch for the RHiNET-2 parallel computing system. RHiNET-2/SW enables high-speed and long-distance data transmission between PC nodes for parallel computing. In RHiNET-2/SW, a one-chip CMOS switch-LSI and eight pairs of 800-Mbit/s × 12-channel parallel optical interconnection modules are mounted into a single compact board. This switch allows high-speed 8-Gbit/s/port parallel optical data transmission over a distance of up to 100 m, and the aggregate throughput is 64 Gbit/s/board. The CMOS-ASIC switching LSI enables high-throughput (64 Gbit/s) packet switching with a single chip. The parallel optical interconnection modules enable high-speed and low-latency data transmission over a long distance. The structure and layout of the printed circuit board is optimized for high-speed, high-density device implementation to overcome electrical problems such as signal propagation-loss and crosstalk. All of the electrical interfaces are composed of high-speed CMOS-LVDS logic (800 Mbit/s/pin). We evaluated the realibility of the optical I/O port through long-term data transmission. No errors were detected during 50 hours of continuous data transmission at a data of 800 Mbit/s × 10 bits (BER: < 2.44×10-14). This test result shows that RHiNET-2/SW can provide high-throughput, long-transmission-length, and highly reliable data transmission in a practical parallel computing system.

効率良い並列処理をサポートするローカルエリア向けネットワークスイッチ

西 宏章，多昌 廣治，工藤 知宏，天野 英晴

電子情報通信学会論文誌 （一般社団法人電子情報通信学会）  J-83-DI （ 2 ） 245-254 - 254 2000年04月

研究論文（研究会，シンポジウム資料等）, 単著, 査読有り,  ISSN  0915-1915

　概要を見る

我々は、PCやWSを相互に接続して効率の良い並列処理を行うための通信アーキテクチャRHiNETの開発を行っている.RHiNETでは, 1箇所に集められた計算機だけでなく, ビル内やフロア内に設置され日常の業務に使用されている計算機を並列処理に利用する.RHiNETで用いるネットワークには, 高性能計算のための高い実効バンド幅と小さなレイテンシ, 及びビル内やフロア内の計算機を接続するためのリンク長と自由なトポロジーが求められる.従来のLANでは、スイッチに大容量のメモリをもつことにより両方の条件を満たす.本論文ではRHiNETのネットワークで用いるスイッチRHiNET / SW1のアーキテクチャと実装について述べる.RHiNET / SW1では, スイッチASIC外部にSRAMによる大容量パケットバッファを備え, 仮想チャネルキャッシュと呼ぶ手法を用いている.また, シミュレータによる性能評価も示す.

RHiNET-2/SW: a large- throughput, compact network- switch using 8.8-Gbit/s optical interconnection

Shinji Nishimura, Katsuyoshi Harasawa, Nobuhiro Matsudaira, Shigeto Akutsu, Tomohiro Kudoh, Hiroaki Nishi, and Hideharu Amano

New Generation Computing 18 （ 2 ） 188-197 2000年01月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り

Low latency high bandwidth message transfer mechanisms for a network interface plugged into a memory slot

Noboru Tanabe, Junji Yamamoto, Hiroaki Nishi, Tomohiro Kudoh, Yoshihiro Hamada, Hironori Nakajo, and Hideharu Amano

Cluster Computing 5 （ 5 ） 7-17 - 17 2000年

研究論文（学術雑誌）, 単著

• Access to Document (DOI)

A local area system network RHiNET-1: A network for high performance parallel computing

H. Nishi, K. Tasho, J. Yamamoto, T. Kudoh, H. Amano

Proceedings of the IEEE International Symposium on High Performance Distributed Computing （IEEE Computer Society）  2000-January   296 - 297 2000年

ISSN  1082-8907

　概要を見る

© 2000 IEEE. The Real World Computing Partnership (RWCP) has developed a local area system network (LASN) called RHiNET-1 (RWCP High-performance NETwork, version 1) using 1.33-Gbps optical interconnections for high-performance computing using personal computers distributed in an office or laboratory environment. The network interface, RHiNET-1/NI, uses a complex programmable logic device (CPLD) based protocol controller to provide an easy evaluation platform for various protocols. It fits in a 32-bit/33-MHz PCI bus. The switch, RHiNET-1/SW, consists of a single-chip CMOS switch and external SRAM. It provides low-latency, reliable communication with a flexible topology design. We are currently evaluating protocols on RHiNET-1. RHiNET-1 will enable a new form of high-performance computing environment. We are also developing the second implementation, RHiNET-2. RHiNET-2/NI will support a 64-bit/66-MHz PCI bus. RHiNET-2/SW is an 8-Gbps/port 8x8 single-chip ASIC switch. The aggregate bandwidth of RHiNET-2/SW is 64 Gbps.

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High-throughput network switch for the RHiNET-2 optically interconnected parallel computing system

Shinji Nishimura, Tomohiro Kudoh, Hiroaki Nishi, Katsuyoshi Harasawa, Nobuhiro Matsudaira, Shigeto Akutsu, Koji Tasyo, Hideharu Amano

Proceedings of SPIE - The International Society for Optical Engineering 4089   562 - 569 2000年

ISSN  0277-786X

　概要を見る

We have produced a prototype network-switch board (the RHiNET-2/SW) for optical interconnection. Eight pairs of 800-Mbit/s×12-channel optical interconnection modules and a one-chip CMOS ASIC switch LSI (a 784-pin BGA package) are mounted on to a single board. This board allows 8-Gbit/s/port parallel optical data transmission over a distance of up to 100 m, and the aggregate throughput is 64 Gbit/s/board. All of the electrical interfaces are composed of CMOS-LVDS logic. We have evaluated the skew of the signal and the reliability of each optical port by measuring the BER. No errors were detected during the 1011-bit packet data transmission at a data rate of 880 Mbit/s×10 bits (8.8 Gbit/s/port). (This corresponds to a BER of less than 10-11). The skew between data channels in one I/O port was less than 141 ps. The fiber length was 50 m. This test result shows that we achieved a high-throughput and long-transmission-length RHiNET-2/SW system using optical interconnection, and that the reliability of the I/O ports in the RHiNET-2/SW is sufficient for the RHiNET-2 parallel computing system.

RHiNET：A network for high performance parallel computing using locally distributed computers

T Kudoh, S Nishimura, J Yamamoto, H Nishi, O Tatebe, H Amano

Innovative Architecture for future generation high performance processors and systems （IEEE COMPUTER SOC）     69 - 73 2000年

査読有り,  ISSN  1063-6404

　概要を見る

A local area distributed computing system called RHiNET (RWCP High Performance Network), in which thousands of commodity personal computers and workstations can be connected by high speed optical interconnection is being developed. RHiNET consists of network interfaces, network switches and optical interconnections. RHiNET will provide a single system image to users and support high performance parallel computing. This paper presents an overview of the system.

RHiNET-2/SW: A high-throughput, compact network-switch using 8.8-Gbit/s optical interconnection

Shinji Nishimura, Katsuyoshi Harasawa, Nobuhiro Matsudaira, Shigeto Akutsu, Tomohiro Kudoh, Hiroaki Nishi, Hideharu Amano

New Generation Computing （SPRINGER VERLAG）  18 （ 2 ） 187 - 197 2000年

査読有り,  ISSN  0288-3635

　概要を見る

We have developed a high-throughput, compact network switch (the RHiNET-2/SW) for a distributed parallel computing system. Eight pairs of 800-Mbit/s×12-channel optical interconnection modules and a CMOS ASIC switch are integrated on a compact circuit board. To realize high-throughput (64 Gbit/s) and low-latency network, the SW-LSI has a customized high-speed LVDS I/O interface, and a high-speed internal SRAM memory in a 784-pin BGA one-chip package. We have also developed device implementation technologies to overcome the electrical problems (loss and crosstalk) caused by such high integration. The RHiNET-2/SW system enables high-performance parallel processing in a distributed computing environment.

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MEMOnet: Network interface plugged into a memory slot

N. Tanabe, J. Yamamoto, H. Nishi, T. Kudoh, Y. Hamada, H. Nakajo, H. Amano

Proceedings - IEEE International Conference on Cluster Computing, ICCC （IEEE Computer Society）  2000-January   17 - 26 2000年

ISSN  1552-5244

　概要を見る

© 2000 IEEE. The communication architecture of the DIMMnet-1 network interface, based on MEMOnet, is described. MEMOnet is an architecture consisting of a network interface plugged into a memory slot. The DIMMnet-1 prototype will have two banks of PC133 based SO-DIMM slots and an 8 Gbps full duplex optical link or two 448 MB/s full duplex LVDS channel links. The software overhead incurred to generate a message is only I CPU cycle and the estimated hardware delay is less than 100 ns using the atomic on-the-fly sending with header TLB. The estimated achievable communication bandwidth with block on-the-fly sending with protection stampable window memory is 440 MB/s which was observed in our experiments writing to the DIMM area with a write combining attribute. This is 3.3 times higher than the maximum bandwidth of PCI. This high performance distributed computing environment is available using economical personal computers with DIMM slots.

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The RDT Router Chip: A versatile router for supporting a distributed shared memory

Hiroaki Nishi, Ken-ichiro Anjo, Tomoiro Kudoh, Hideharu Amano

IEICE TRANSACTIONS on Information and Systems E80-D （ 9 ） 854-862 1997年09月

研究論文（学術雑誌）, 共著

相互結合網RDT上での階層マルチキャストによるメモリコヒーレンシ維持手法

西村 克信，工藤 知宏，西 宏章，楊 愚魯，天野 英晴

情報処理学会論文誌「並列処理」特集 37   1367-1377 1996年08月

研究論文（学術雑誌）, 共著