研究者詳細 - 西　宏章

論文 - 西　宏章

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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

© 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

© 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

© 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

© 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

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 CO<sub>2</sub> concentration. In this paper, we propose a novel method to allocate power optimally by using learning efficiency, which contains both PMV and CO<sub>2</sub> 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

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

© 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

© 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

© 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

© 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

© 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

© 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

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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

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

© 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

© 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

© 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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