研究者詳細 - 西　宏章

論文 - 西　宏章

分割表示 314 件中 201 - 220 件目／全件表示 >>

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

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．

Access to Document (DOI)

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

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.

Access to Document (DOI)

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

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

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.

Access to Document (DOI)

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

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.

Access to Document (DOI)

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

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.

Access to Document (DOI)

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

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.

Access to Document (DOI)

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

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.

Access to Document (DOI)

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

Access to Document (DOI)

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

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.

Access to Document (DOI)

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

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.

Access to Document (DOI)

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

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.

Access to Document (DOI)

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

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

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 CO<sub>2</sub> 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.

Access to Document (DOI)

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

　前のページ - 次のページ　

西 宏章

論文 - 西 宏章

西　宏章

論文 - 西　宏章