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OHTA Chikara
Graduate School of System Informatics / Department of System Informatics
Professor

Researcher basic information

■ Research Areas
  • Informatics / Information networks
  • Informatics / Computer systems

Research activity information

■ Award
  • Jan. 2024 Ministry of Internal Affairs and Communications, Research and Development Encouragement Award, Strategic Information and Communications R&D Promotion Programme, Research and development of wired/wireless cooperative communication technology to reduce the weight of in-vehicle harnesses
    Chikara Ohta, Makoto Okuhara, Satoru Shimizu
    共同研究・競争的資金等の業績IDIRI

  • Nov. 2019 The 6th International Workshop on Smart Wireless Communications, Best Paper Awad, Joint Channel and AP/STA Assignment for Infrastructure-Mode IEEE 802.11 Multi-Interface Wireless Mesh Networks
    TAKAHASHI Tomoki, KAMADA Tomoki, OHTA Chikara, TAMURA Naoki, MAENO Taka
    International society

  • Jul. 2019 IEICE Technical Committee MoNA, 2018 Young Research Award, Optimal Configuration Method for Multi Wi-Fi Interface Mesh Networks Operating in Infrastructure Mode
    TAKAHASHI Tomoki, MAENO Taka, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara, TAMURA Naoyuki
    Japan society

  • Sep. 2018 The Institute of Electronics, Information and Communication Engineers, Communications Society, Outstanding Contributions Award, For contribution as an Editor-in-Chief of IEICE Communications Express
    OHTA CHIKARA
    Others

  • Sep. 2017 一般社団法人産業応用工学会, Best Paper Award, Estimation of Calf Weight from Fixed-Point Stereo Camera Images Using Three-Dimensional Successive Cylindrical Model
    山下 歩, OHKAWA TAKENAO, 大山 憲二, 太田 能, 西出 亮, 本多 健
    International society

  • Apr. 2008 財団法人 電気・電子学術振興財団, 第10回LSI IPデザイン・アワード 研究助成賞, 長波帯標準電波を用いた低電力センサノードの垂直統合設計
    OTAKE Yu, ICHIEN Masumi, TAKEUCHI Takashi, GION Akihiro, MIKAMI Shinji, FUJIWARA Hidehiro, KAWAGUCHI Hirosi, OHTA Chikara, YOSHIMOTO Masahiko

  • Dec. 2007 IEEE, SENSORCOMM 2007 ENOPT 2008 Workshop Best Paper Award, Cross-Layer Design for Low-Power Wireless Sensor Node Using Long-Wave Standard Time Code
    OTAKE Yu, ICHIEN Masumi, TAKEUCHI Takashi, GION Akihiro, MIKAMI Shinji, FUJIWARA Hidehiro, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko

■ Paper
  • Zhiyi Zhu, Junjun Zheng, Eiji Takimoto, Patrick Finnerty, Chikara Ohta
    IEEE, Oct. 2024, 2024 6th International Conference on System Reliability and Safety Engineering (SRSE), 469 - 474
    International conference proceedings

  • Yu Sun, Patrick Finnerty, Chikara Ohta
    Institute of Electrical and Electronics Engineers (IEEE), Mar. 2024, IEEE Access, 12, 45164 - 45175
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Hajime Migita, Yuki Nakagoshi, Patrick Finnerty, Chikara Ohta, Makoto Okuhara
    Institute of Electrical and Electronics Engineers (IEEE), Mar. 2024, IEICE Transactions on Communications, 1 - 13, English
    Scientific journal

  • Sidi Mohamed Mohi Dine, Patrick Finnerty, Chikara Ohta
    Last, Institute of Electrical and Electronics Engineers (IEEE), Jan. 2024, IEEE Access, 12, 8110 - 8122, English
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Makoto Okuhara, Nobuyuki Kurioka, Shigeki Mitoh, Patrick Finnerty, Chikara Ohta
    Institute of Electrical and Electronics Engineers (IEEE), 2024, IEEE Open Journal of Vehicular Technology, 1 - 14
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Ryota Matsumoto, Patrick Finnerty, Chikara Ohta, Tomio Kamada
    2024, IEEE Vehicular Networking Conference, VNC, 255 - 256
    International conference proceedings

  • Zhiyi Zhu, Eiji Takimoto, Patrick Finnerty, Chikara Ohta
    Institute of Electrical and Electronics Engineers (IEEE), 2024, IEEE Access, 1 - 1
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Interference Suppression Arbitration Control for In-vehicle Ultra Wideband Wireless Networks
    Makoto Okuhara, Nobuyuki Kurioka, Patrick Finnerty, Chikara Ohta
    Oct. 2023, Proceedings of The 9th IEEE World Forum on Internet of Things, English
    International conference proceedings

  • Mohi Dine Sidi Mohamed, Finnerty Patrick, Chikara Ohta
    Institute of Electronics, Information and Communications Engineers (IEICE), Sep. 2023, IEICE Communications Express, 12(9) (9), 511 - 516
    Scientific journal

  • Patrick Finnerty, Tomio Kamada, Chikara Ohta
    Wiley, Apr. 2023, Concurrency and Computation: Practice and Experience, English
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Yoshiki Kawanishi, Patrick Finnerty, Tomio Kamada, Chikara Ohta
    ACM, Feb. 2023, Proceedings of the 14th International Workshop on Programming Models and Applications for Multicores and Manycores
    International conference proceedings
    Link to Kobe Univ. Repository (Kernel)

  • Hajime Migita, Makoto Takenaka, Patrick Finnerty, Makoto Okuhara, Chikara Ohta
    Institute of Electronics, Information and Communications Engineers (IEICE), 2023, IEICE Communications Express
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Hajime Migita, Taiyo Tanaka, Shuji Yamaguchi, Makoto Takenaka, Patrick Finnerty, Tomio Kamada, Chikara Ohta
    Corresponding, IEEE, Oct. 2022, 2022 IEEE 8th World Forum on Internet of Things (WF-IoT), English
    International conference proceedings
    Link to Kobe Univ. Repository (Kernel)

  • Patrick Finnerty, Yoshiki Kawanishi, Tomio Kamada, Chikara Ohta
    Sep. 2022, Scientific Programming
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Chikara Ohta, Taiyo Tanaka, Hajime Migita, Shuji Yamaguchi, Makoto Takenaka, Patrick Finnerty, Tomio Kamada
    Institute of Electronics, Information and Communications Engineers ({IEICE}), Jul. 2022, IEICE Communications Express, 11(7) (7), 429 - 434, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Patrick Finnerty, Tomio Kamada, Chikara Ohta
    Last, ACM, Apr. 2022, Proceedings of the Thirteenth International Workshop on Programming Models and Applications for Multicores and Manycores, English
    [Refereed]
    International conference proceedings
    Link to Kobe Univ. Repository (Kernel)

  • Ryota Matsumoto, Patrick Finnerty, Chikara Ohta
    Institute of Electronics, Information and Communications Engineers ({IEICE}), 2022, IEICE Communications Express, English
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Enami Naoko, Uemura Saai, Asano Koh, Finnerty Patrick, Kamada Tomio, Ohta Chikara
    The purpose of this research is to share pedestrian information among multiple vehicles by vehicle-to-vehicle communication and detect the positions of all pedestrians around the vehicle. In the past, we have proposed a method of collating shared pedestrian information through image-based person Re-Identification (ReID). In this paper, in order to improve the accuracy of pedestrian information collation, the state-of-the-art ReID network is adapted to our scenario by fine-tuning. In addition, a new pedestrian image dataset for sharing pedestrian information was constructed. In our experiments using our dataset, the proposed method improved the pedestrian information collation accuracy.
    The Institute of Electronics, Information and Communication Engineers, 2022, IEICE Communications Express, advpub, English

  • Yuki Yamamoto, Takenao Ohkawa, Chikara Ohta, Kenji Oyama, Ryo Nishide
    MDPI, Nov. 2021, The 13th EFITA International Conference, English
    [Refereed]
    International conference proceedings
    Link to Kobe Univ. Repository (Kernel)

  • Daigo Yasuda, Patrick Finnerty, Tomio Kamada, Chikara Ohta
    Last, Oct. 2021, IEICE Communications Express, 10(10) (10), 792 - 797, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Tomoya Tanaka, Tomio Kamada, Chikara Ohta
    Last, Wiley, Jun. 2021, International Journal of Network Management, 31(6) (6), English
    [Refereed]
    Scientific journal

  • FINNERTY Patrick, KAMADA Tomio, OHTA Chikara
    Last, Feb. 2021, Concurrency and Computation: Practice and Experience, e6224(2) (2), English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • JIKYO Takuto, KAMADA Tomio, OHTA Chikara, YAGUCHI Takaharu, OYAMA Kenji, OHKAWA Takenao, NISHIDE Ryo
    IEEE, Jan. 2021, 2021 IEEE 18th Annual Consumer Communications & Networking Conference (CCNC)
    [Refereed]
    International conference proceedings

  • Liuyi Yang, Tomio Kamada, Chikara Ohta
    Last, 2021, IEICE COMMUNICATIONS EXPRESS, 10(8) (8), 564 - 569, English
    [Refereed]
    Scientific journal

  • Koji Yamamoto, Tomoyuki Ohta, Chikara Ohta, Kenya Sato, Hiroo Sekiya, Shigeaki Tagashira, Katsuhiro Naito, Jin Nakazawa, Kanae Matsui, Susumu Ishihara
    Dec. 2020, IEICE Transactions on Communications, E103B(12) (12), 1375
    Scientific journal

  • TANAKA Tomoya, KAMADA Tomio, OHTA Chikara
    Dec. 2020, IEICE Communications Express, 9(12) (12), 616 - 621, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • URAKAWA Go, KASHIHARA Shigeru, YAMAMOTO Atsushi, MATSUZAKI Kenta, MIYAZAKI Kosei, WADA Masashi, SEKI Tomoya, OHTA Chikara, FUKUMOTO Masahiro
    IEEE, Oct. 2020, 2020 IEEE Global Humanitarian Technology Conference (GHTC), English
    [Refereed]
    International conference proceedings
    Link to Kobe Univ. Repository (Kernel)

  • TANAKA Tomoya, KAMADA Tomio, OHTA Chikara
    Last, IEEE, Sep. 2020, 2020 21st Asia-Pacific Network Operations and Management Symposium (APNOMS), 85 - 90, English
    [Refereed]
    International conference proceedings

  • IoC: Internet of Cows - Grazing Cattle Management System based on Interaction Analysis
    YAMAUCHI Yohei, YAMANISHI Takahiro, FUKUMOTO Shunta, JIKYO Takuto, OHTA Chikara, NISHIDE Ryo, OYAMA Kenji, YAGUCHI Takaharu, OHKAWA Takenao
    Jul. 2020, Information Processing Society of Japan, Digital Practice, 11(3) (3), 511 - 532, Japanese
    [Refereed][Invited]
    Research society

  • FINNERTY Patrick, KAMADA Tomio, OHTA Chikara
    Last, ACM, Feb. 2020, Proc. of the 11th International Workshop on Programming Models and Applications for Multicores and Manycores (PMAM' 20), 1 - 10, English
    [Refereed]
    International conference proceedings

  • NAGATO Takehiro, TSUTANO Takumi, KAMADA Tomio, TAKAKI Yumi, OHTA Chikara
    Last, Institute of Electronics, Information and Communications Engineers (IEICE), Jan. 2020, IEICE Transactions on Communications, E103-B(1) (1), 20 - 31, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Joint Channel and AP/STA Assignment for Infrastructure-Mode IEEE 802.11 Multi-Interface Wireless Mesh Networks
    TAKAHASHI Tomoki, KAMADA Tomio, OHTA Chikara, TAMURA Naoyuki, MAENO Taka
    Nov. 2019, Proceedings of the 6th International Workshop on Smart Wireless Communications, 12 - 17
    [Refereed]
    International conference proceedings

  • Wi-SF: Aerial Wi-Fi Sensing Function for Enhancing Search and Rescue Operation
    KASHIHARA Shigeru, YAMAMOTO Atsushi, MATSUZAKI Kenta, MIYAZAKI Kosei, SEKI Tomoya, URAKAWA Go, FUKUMOTO Masahiro, OHTA
    Oct. 2019, Proceedings of 2019 IEEE Global Humanitarian Technology Conference (GHTC 2019), 423 - 426, English
    [Refereed]
    International conference proceedings

  • Towards Practical Utilization of Unmanned Aerial Vehicle in Disaster Mitigation - UAV Operation Drill -
    KASHIHARA Shigeru, YAMAMOTO Atsushi, MATSUZAKI Kenta, MIYAZAKI Kosei, SEKI Tomoya, URAKAWA Go, FUKUMOTO Masahiro, OHTA
    Oct. 2019, Proceedings 2019 IEEE Global Humanitarian Technology Conference (GHTC 2019), 414 - 415, English
    [Refereed]
    International conference proceedings

  • Image Extraction Based on Depth Information for Calf Body Weight Estimation
    FUKUDA Naoki, OHKAWA Takenao, OHTA Chikara, OYAMA Kenji, TAKAKI Yumi, NISHIDE Ryo
    Jun. 2019, 12th European Federation for Information Technology in Agriculture, Food and the Environment (EFITA) International Conference, English
    [Refereed]
    International conference proceedings

  • Detection of Approaching Interaction with Cattle in Estrus Based on Community Transition and Cattle Distance
    FUKUMOTO Shunta, NISHIDE Ryo, TAKAKI Yumi, OHTA Chikara, OYAMA Kenji, OHKAWA Takenao
    Jun. 2019, 12th European Federation for Information Technology in Agriculture, Food and the Environment (EFITA) International Conference, English
    [Refereed]
    International conference proceedings

  • Rate Adaptation Mechanism with Available Data Rate Trimming and Data Rate Information Provision for V2I Communications
    KASHIHARA Shigeru, SAHARA Takemi, KANEDA Shigeru, OHTA Chikara
    Hindawi, Apr. 2019, International Journal of Mobile Information Systems, 2019, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Distributed Key-Value Storage for Edge Computing and Its Explicit Data Distribution Method
    NAGATO Takehiro, TSUTANO Takumi, KAMADA Tomioi, TAKAKI Yumi, OHTA Chikara
    Last, IEEE, Jan. 2019, Proceedings of the 33th International Conference on Information Networking (ICOIN 2019), E103-B(1) (1), 20 - 31, English
    [Refereed]
    International conference proceedings

  • MAESAKO Keisuke, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    IEEE, Jan. 2019, Proceedings of IEEE Consumer Communications & Networking Conference (CCNC 2019), 1 - 7, English
    [Refereed]
    International conference proceedings

  • Kou Asano, Naoko Enami, Tomio Kamada, Chikara Ohta
    IEEE, 2019, Proceedings of IEEE Intelligent Transportation Systems Conference (ITSC2019), 764 - 770, English
    [Refereed]
    International conference proceedings

  • Takahiro Yamanishi, Takuto Jikyo, Tomio Kamada, Ryo Nishide, Chikara Ohta, Kenji Oyama, Takenao Ohkawa
    Institute of Electronics, Information and Communications Engineers ({IEICE}), 2019, IEICE Communications Express
    [Refereed]

  • Takuto Jikyo, Takahiro Yamanishi, Tomio Kamada, Ryo Nishide, Chikara Ohta, Kenji Oyama, Takenao Ohkawa
    Institute of Electronics, Information and Communications Engineers ({IEICE}), 2019, IEICE Communications Express
    [Refereed]

  • Refined Cattle Detection Using Composite Background Subtraction and Brightness Intensity from Bird’s Eye Images
    AOTANI MAMI, NISHIDE RYO, TAKAKI YUMI, OHTA CHIKARA, OYAMA KENJI, OHKAWA TAKENAO
    Dec. 2018, Proceedings of the 9th International Symposium on Information and Communication Technology, 243 - 250, English
    [Refereed]
    International conference proceedings

  • Quantifying the Approaching Behaviors for Interactions in Detecting Estrus of Breeding Cattle
    FUKUMOTO SHUNTA, NISHIDE RYO, TAKAKI YUMI, OHTA CHIKARA, OYAMA KENJI, OHKAWA TAKENAO
    Dec. 2018, Proceedings of the 9th International Symposium on Information and Communication Technology, 235 - 242, English
    [Refereed]
    International conference proceedings

  • Cattle Community Extraction Using the Interactions Based on Synchronous Behavior
    YAMAUCHI YOHEI, NISHIDE RYO, TAKAKI YUMI, OHTA CHIKARA, OYAMA KENJI, OHKAWA TAKENAO
    Dec. 2018, Proceedings of the 9th International Symposium on Information and Communication Technology, 227 - 234, English
    [Refereed]
    International conference proceedings

  • Calf Robust Weight Estimation Using 3D Contiguous Cylindrical Model and Directional Orientation from Stereo Images
    NISHIDE RYO, YAMASHITA AYUMI, TAKAKI YUMI, OHTA CHIKARA, OYAMA KENJI, OHKAWA TAKENAO
    Dec. 2018, Proceedings of the 9th International Symposium on Information and Communication Technology, 208 - 215, English
    [Refereed]
    International conference proceedings

  • Yumi Takaki, Makoto Ando, Keisuke Maesako, Keisuke Fujita, Tomio Kamada, Chikara Ohta, Hisashi Tamaki
    SAGE Publications Ltd, Jan. 2018, International Journal of Distributed Sensor Networks, 14(1) (1), English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Ayumi Yamashita, Takenao Ohkawa, Kenji Oyama, Chikara Ohta, Ryo Nishide, Takeshi Honda
    Various studies have been conducted on methods for estimating the weight of cattle. In this study, we propose a method to estimate body weight by modeling the shape of calf using three-dimensional information extracted from the stereo images. Initially, a stereo camera is set with two fixed network cameras, to take a motion image of a calf. Three-dimensional coordinate is calcu
    The Institute of Industrial Applications Engineers, Jan. 2018, Journal of the Institute of Industrial Applications Engineers (JIIAE), 6(1) (1), 39 - 46, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • A Study for Improvement of Throughput in High-Density Wireless Networks Using Transmitting Opportunity Control
    KAWASAKI Takahiro, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara
    IEEE, Jan. 2018, Proceedings of the 32th International Conference on Information Networking (ICOIN 2018), 140 - 145, English
    [Refereed]
    International conference proceedings

  • Achieving High Throughput and Fairness in Dense WLANs by Mitigating Problem Nodes
    ROSLAN Irda, KAWASAKI Takahiro, NISHIUE Toshiki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    Reserch Indis Publications, Nov. 2017, International Journal of Applied Engineering Research, 12(24) (24), 15409 - 15419, English
    [Refereed]
    Scientific journal

  • Ayumi Yamashita, Takenao Ohkawa, Kenji Oyama, Chikara Ohta, Ryo Nishide, Takeshi Honda
    Various studies have been conducted on methods for estimating the weight of cattle. In this study, we propose a method to estimate body weight by modeling the shape of calf using three-dimensional information extracted from the stereo images. Initially, a stereo camera is set with two fixed network cameras, to take a motion image of a calf. Three-dimensional coordinate is calcu
    The Institute of Industrial Applications Engineers, Jul. 2017, The 5th IIAE International Conference on Intelligent Systems and Image Processing 2017 (ICISIP2017), 247 - 254, English
    [Refereed]
    International conference proceedings

  • Ryo Nishide, Yoji Hosomi, Takenao Ohkawa, Kenji Oyama, Chikara Ohta
    Breeding cows are known to engage in social activities, such as interacting with other cows and forming groups similarly to humans. This paper proposes a method to extract information of interaction between cows, regarding it as a primary element of sociality. In order to extract such information, we record bird's eye pictures in a pasture by a fixed point camera set on a silo
    The Institute of Industrial Applications Engineers, Jul. 2017, The 5th IIAE International Conference on Intelligent Systems and Image Processing 2017 (ICISIP2017), 239 - 246, English
    [Refereed]
    International conference proceedings

  • 車車間通信を利用した歩行者検出性能向上手法の検討
    KABAYASHI Ryosuke, ENAMI Naoko, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    Feb. 2017, 電子情報通信学会パターン認識・メディア理解研究会, Japanese
    Scientific journal

  • Control of Transmission Power and Carrier Sense Threshold to Enhance Throughput and Fairness for Dense WLANs
    Irda Roslan, Takahiro Kawasaki, Toshiki Nishiue, Yumi Takaki, Chikara Ohta, Hisashi Tamaki
    2016, 2016 INTERNATIONAL CONFERENCE ON INFORMATION NETWORKING (ICOIN), 51 - 56, English
    [Refereed]
    International conference proceedings

  • A Study on Penetration Strategy of On-board Unit Taking Account of the Type of Vehicles in V2V Communications
    Hiroaki Minami, Yumi Takaki, Chikara Ohta, Hisashi Tamaki
    2016, 2016 INTERNATIONAL CONFERENCE ON INFORMATION NETWORKING (ICOIN), 35 - 39, English
    [Refereed]
    International conference proceedings

  • Keisuke Fujita, Yumi Takaki, Chikara Ohta, Hisashi Tamaki
    2016, INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS, 2016, 1 - 10, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • TAKAKI Yumi, MINAMI Hiroaki, OHTA Chikara, TAMAKI Hisashi
    Recent years have seen a great deal of research into Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communications, which will contribute to advances in driving support systems. In contrast to V2I communications, V2V communications offer the advantage of not requiring infrastructure, but introduction of such systems is not expected to be effective unless there is sufficient penetration by On-Board Units (OBUs). For that reason, it is essential to determine what extent of penetration should be encouraged in the initial stage in order to attain effectiveness. Therefore, we focus on the fact that even though Large Vehicles (LVs) such as large commercial freight carriers are large and tall, and are obstacles blocking V2V communications from the viewpoint of Small Vehicles (SVs), antennas on LVs could also be used to relay communications, thereby facilitating the success of such systems.
      This paper presents experiment s simulating traffic environment s consisting of mixed LVs and SVs, and examined how data V2V communication distribution rates varied with changes of the percentage of vehicles equipped with OBUs. Through the simulation experiments, by causing actively penetrate LVs, it revealed that the reception rate of SVs can be improved, and clarified some guidelines for policies that could encourage wider usage.
    日本シミュレーション学会, Dec. 2015, 日本シミュレーション学会論文誌, 7(4) (4), 125 - 133, Japanese
    [Refereed]

  • Takahiro Iwami, Irda Roslan, Yumi Takaki, Kyoko Yamori, Chikara Ohta, Hisashi Tamaki
    Aug. 2015, IEICE TRANSACTIONS ON COMMUNICATIONS, E98B(8) (8), 1700 - 1714, English
    [Refereed]
    Scientific journal

  • In-network guidance for new-generation content distribution
    Miki Yamamoto, Hideki Tode, Chikara Ohta, Tomohiko Yagyu
    National Institute of Information and Communications Technology, 2015, Journal of the National Institute of Information and Communications Technology, 62(2) (2), 83 - 92, English
    Scientific journal

  • Demo: Contents Sharing among Mobile Users in Breadcrumbs-enabled Cache Network
    Tomohiko Yagyu, Miki Yamamoto, Hideki Tode, Chikara Ohta, James F. Kurose
    2015, 2015 12TH ANNUAL IEEE CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE, 150 - 151, English
    [Refereed]
    International conference proceedings

  • Performance Evaluation of Emergency Vehicle Travel Support System Based on V2V Communications
    MINAMI Hiroaki, KINOSHITA Atsushii, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEEE, Jan. 2015, Proceedings of the 14th International Conference on Electronics, Information, and Communication (ICEIC2015), 1 - 2, English
    [Refereed]
    International conference proceedings

  • Side Trip Multi-path Routing Protocol for Spatial Node Failure Tolerance in Data-gathering WSNs
    Keisuke Fujita, Yumi Takaki, Chikara Ohta, Hisashi Tamaki
    2014, 2014 IEEE 11TH CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE (CCNC), 702 - 707, English
    [Refereed]
    International conference proceedings

  • 二次元通信システムにおける定在波を考慮した入力点選択型給電方式に関する研究
    TESHIMA Kosuke, MATSUDA Takasha, ZHANG Bing, INAMOTO Tsutomu, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    二次元通信システムとは,シート状通信媒体を用いた通信システムであり,シート内にマイクロ波を閉じ込めて伝搬させることでシート上の端末に限定した通信と給電を同時に実現することをねらっている.しかし,二次元通信システムにおける給電には課題がある.シンクノードからシートに入力されたマイクロ波は反射によって定在波を形成する.このため受信電力が弱くなるヌル点が複数形成され,このヌル点上の端末への給電効率は低くなる.そこで本論文では,入力点の位置に応じてヌル点の位置も変化することに着目し,複数の入力点を適切に切り換えることによって複数端末に対し総給電量を減らすように給電を行う入力点選択型給電方式を提案する.また,どの入力点からどれだけの期間,どのような順番で給電すると給電量を最小化できるかという給電量最小化問題として定式化する.この問題を解くためには,ある入力点から一定時間給電後のセンサノードのキャパシタ電圧を知る必要がある.本論文では,具体的なセンサノードのインピーダンスや受信電力を知ることなく,センサノードのキャパシタ電圧の推移から一定時間給電後のセンサノードのキャパシタ電圧を推定する方法も併せて検討する.例題において,提案方式が従来の一つの入力点を使った給電方式に比べて給電時間を87.6%減らすことができ,一点入力では十分な給電が不可能な例においても提案方式によって十分な給電が可能であることが示された.
    The Institute of Electronics, Information and Communication Engineers, Dec. 2013, 電子情報通信学会論文誌B, J96-B(12) (12), 1342 - 1354, Japanese
    [Refereed]

  • Power Provision Scheme Considering Shadowing Effect for Two-Dimensional Communication Systems
    Toshinori Kagawa, Takashi Matsuda, Bing Zhang, Ryu Miura, Youiti Kado, Kosuke Teshima, Chikara Ohta
    2013, 2013 19TH ASIA-PACIFIC CONFERENCE ON COMMUNICATIONS (APCC): SMART COMMUNICATIONS TO ENHANCE THE QUALITY OF LIFE, 525 - 530, English
    [Refereed]
    International conference proceedings

  • Takahiro Iwami, Yumi Takaki, Kyoko Yamori, Chikara Ohta, Hisashi Tamaki
    IEEE, 2013, IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 2125 - 2130, English
    [Refereed]
    International conference proceedings

  • Efficient Urban Broadcast Protocol for V2V Communications with Relay Control
    Ke Cao, Atsushi Kinoshita, Yumi Takaki, Chikara Ohta, Hisashi Tamaki
    2013, 2013 IEEE VEHICULAR NETWORKING CONFERENCE (VNC), 24 - 30, English
    [Refereed]
    International conference proceedings

  • Hiroki Kawabata, Yumi Takaki, Chikara Ohta, Hisashi Tamaki, Takaki Onizuka
    2013, CONEXT STUDENT WORKSHOP '13, 39 - 41, English
    [Refereed]
    International conference proceedings

  • Akindele Segun Afolabi, Erdenebileg Munkhbat, Yumi Takaki, Chikara Ohta, Hisashi Tamaki, Yoshizo Tanaka, Takashi Yamamoto, Yoji Okada
    Oct. 2012, IEICE TRANSACTIONS ON COMMUNICATIONS, E95B(10) (10), 3353 - 3357, English
    [Refereed]
    Scientific journal

  • Content/Location Mapping with Cache-Location Resolution for In-network Guidance
    KAWABATA Hiroki, HASHIMOTO Kensuke, TAKAKI Yumi, INAMOTO Tsutomu, OHTA Chikara, TAMAKI Hisashi
    Aug. 2012, Proceedings of the 4th International Conference on Advances in Future Internet, 1 - 6, English
    [Refereed]
    International conference proceedings

  • Takashi Matsuda, Shintaro Izumi, Yasuharu Sakai, Takashi Takeuchi, Hidehiro Fujiwara, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    Jan. 2012, IEICE TRANSACTIONS ON COMMUNICATIONS, E95B(1) (1), 178 - 188, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Gradually Resolving Procedures by a Trip-based Integer Programming to Optimize Elevator Operations
    Tsutomu Inamoto, Chikara Ohta, Hisashi Tamaki
    2012, 6TH INTERNATIONAL CONFERENCE ON SOFT COMPUTING AND INTELLIGENT SYSTEMS, AND THE 13TH INTERNATIONAL SYMPOSIUM ON ADVANCED INTELLIGENT SYSTEMS, 626 - 632, English
    [Refereed]
    International conference proceedings

  • An Implementation of Dynamic Programming for Many-Core Computers
    INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    Sep. 2011, Proceedings of SICE Annual Conference 2011, pp. 961-966, English
    [Refereed]
    International conference proceedings

  • MANET における距離情報にもとづく RAD 制御を用いたブロードキャスト方式の提案と評価
    TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    Jun. 2011, 電子情報通信学会論文誌, Vol. J94-B, No. 06, pp. 765-77, Japanese
    [Refereed]
    Scientific journal

  • A Novel Co-operative Channel Assignment Scheme for Indoor Base Stations
    Akindele Segun Afolabi, OHTA Chikara, TAMAKI Hisashi
    Feb. 2011, GSTF International Journal on Computing (JoC), vol.1, no.2, pp.205-210, English
    [Refereed]
    Scientific journal

  • Akindele Segun Afolabi, Chikara Ohta, Hisashi Tamaki
    2011, 2011 International Symposium on Modeling and Optimization of Mobile, Ad Hoc, and Wireless Networks, WiOpt 2011, CD-Paper, 434 - 439, English
    [Refereed]
    International conference proceedings

  • In-network Hop-aware Query Induction Scheme for Implicit Coordinated Content Caching
    Kensuke Hashimoto, Yumi Takaki, Chikara Ohta, Hisashi Tamaki
    2011, PROCEEDINGS OF THE THIRD INTERNATIONAL CONFERENCE ON ADVANCES IN FUTURE INTERNET (AFIN 2011), pp. 106-109, 69 - 73, English
    [Refereed]
    International conference proceedings

  • Fair Resource Partitioning Between Cell-center and Cell-edge of FFR-based Multi-tier Wireless Access Networks
    Akindele Segun Afolabi, Erdenebileg Munkbat, Chikara Ohta, Hisashi Tamaki
    2011, 2011 7TH INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS, NETWORKING AND MOBILE COMPUTING (WICOM), CD-Paper, English
    [Refereed]
    International conference proceedings

  • A Base Station Co-operation Protocol for Indoor Base Stations
    Akindele Segun Afolabi, OHTA Chikara, TAMAKI Hisashi
    Nov. 2010, Proceedings Annual International Conference on Network Technologies & Communications (NTC2010), pp.N37-42, English
    [Refereed]
    International conference proceedings

  • Takashi Matsuda, Takashi Takeuchi, Takefumi Aonishi, Masumi Ichien, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    Network protocols for wireless sensor networks should be evaluated in terms of life time in a whole system. There exists power variation node due to the manufacturing variation. In this paper, we develop a power model, in which we consider threshold-voltage variation. We implement it to QualNet in order to evaluate the impact against a life time. The simulation results show that the conventional model has overestimated the life time longer than our model when nodes are randomly deployed. In addition, the network life time is extended by 19.3% compared with the conventional model by an optimum deployment.
    The Institute of Electronics, Information and Communication Engineers(IEICE), Mar. 2010, IEICE Electron. Express, Vol. 7, No. 3, pp.197-202(3) (3), 197 - 202, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Shintaro Izumi, Takashi Takeuchi, Takashi Matsuda, Hyeokjong Lee, Toshihiro Konishi, Koh Tsuruda, Yasuharu Sakai, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    Mar. 2010, IEICE TRANSACTIONS ON ELECTRONICS, E93C(3) (3), 261 - 269, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Toru Yoshikawa, Shinichiro Kawasaki, Masahiro Takase, Yasushi Hiraoka, Yumi Takaki, Chikara Ohta, Takeshi Inoue
    2010, ICUFN 2010 - 2nd International Conference on Ubiquitous and Future Networks, 177 - 182, English
    [Refereed]
    International conference proceedings

  • INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    In this paper, an approach to complement legacy rules for the elevator operation is proposed. The approach is derived from the analysis that the elevator operation in the real world often obeys a heuristic rule, and such a rule can be divided into a legacy rule and ad-hoc rules. In the approach, ad-hoc rules are represented as polysemous rules, and a Genetics-Based Machine Learning (GBML) method is applied to acquire such rules. Here, a polysemous rule encodes, not a set of environments' states as the well-known if-then rule does, but a relative attribute vector of an arbitrary elevator. The elevator selection rule based on polysemous rules is simple: if there is a polysemous rule which matches one of attribute vectors of the elevators, select the elevator which corresponds to the matching vector; otherwise select an elevator according to a legacy rule. In computer illustrations, the GBML method is applied to 3 traffic patterns formed by the system's users. It is shown that the resultant polysemous rules seem to complement an existing (legacy) operational rule. Furthermore, polysemous rules, which are selected among those acquired by the GBML method, are successfully applied to harder problems with more elevators than those used in learning.
    The Japan Society of Mechanical Engineers, 2010, Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol. 4, No. 3, pp. 651-663(3) (3), 651 - 663, English
    [Refereed]
    Scientific journal

  • Augusto Foronda, Chikara Ohta, Hisashi Tamaki
    Jun. 2009, IEICE TRANSACTIONS ON COMMUNICATIONS, E92B(6) (6), 2160 - 2167, English
    [Refereed]
    Scientific journal

  • Takashi Takeuchi, Shinji Mikami, Hyeokjong Lee, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    Jun. 2009, IEICE TRANSACTIONS ON ELECTRONICS, E92C(6) (6), 815 - 821, English
    [Refereed]
    Scientific journal

  • 低消費電力センサノードVLSIのための時刻同期型MACプロトコルの研究
    IZUMI Shintaro, MATSUDA Takashi, TAKEUCHI Takashi, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    Mar. 2009, 電子情報通信学会技術研究報告(信学技報), vol. 108, no. 457, NS2008-174,(457(NS2008 143-233)) (457(NS2008 143-233)), Japanese
    International conference proceedings

  • A Simple Approach on Mitigating the Gray Zone Effect to Improve Throughput in IEEE802.11 based Ad-hoc Network
    Nhy Nguyen Tu Pham, Yiyuan Diao, Yusuke Kato, Kenichiro Yagura, Yumi Takaki, Chikara Ohta
    2009, MESH: 2009 SECOND INTERNATIONAL CONFERENCE ON ADVANCES IN MESH NETWORKS, 7 - 11, English
    [Refereed]
    International conference proceedings

  • Implementation and Experiment of Publish/Subscribe System on Wireless Mesh Networks - Word-mouth Information Distribution Service
    Yusuke Kato, Yiyuan Diao, Nhy Nguyen Tu Pham, Ken-ichiro Yagura, Takayuki Kitada, Kazuhiro Yamaguchi, Yumi Takaki, Mitsuhiro Kuwano, Chikara Ohta
    2009, MESH: 2009 SECOND INTERNATIONAL CONFERENCE ON ADVANCES IN MESH NETWORKS, 103 - +, English
    [Refereed]
    International conference proceedings

  • A 58-mu W Single-Chip Sensor Node Processor Using Synchronous MAC Protocol
    Takashi Takeuchi, Shintaro Izumi, Takashi Matsuda, Hyeokjong Lee, Yu Otake, Toshihiro Konishi, Koh Tsuruda, Yasuharu Sakai, Hidehiro Fujiwara, Chikara Ohta, Hiroshi Kawaguchi, Masahiko Yoshimoto
    2009, 2009 SYMPOSIUM ON VLSI CIRCUITS, DIGEST OF TECHNICAL PAPERS, 290 - 291, English
    [Refereed]
    International conference proceedings

  • Takashi Takeuchi, Shintaro Izumi, Takashi Matsuda, Hyeokjong Lee, Toshihiro Konishi, Koh Tsuruda, Yasuhiro Sakai, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2009, 2009 INTERNATIONAL SOC DESIGN CONFERENCE (ISOCC 2009), 202 - 207, English
    [Refereed]
    International conference proceedings

  • Tsutomu Inamoto, Chikara Ohta, Hisashi Tamaki, Hajime Murao
    Institute of Electrical Engineers of Japan, 2009, IEEJ Transactions on Electronics, Information and Systems, 129(7) (7), 10 - 1245, English
    [Refereed]

  • Takashi Takeuchi, Yu Otake, Masumi Ichien, Akihiro Gion, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    Nov. 2008, IEICE TRANSACTIONS ON COMMUNICATIONS, E91B(11) (11), 3480 - 3488, English
    [Refereed]
    Scientific journal

  • Shintaro Izumi, Takashi Takeuchi, Takashi Matsuda, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    Nov. 2008, IEICE TRANSACTIONS ON COMMUNICATIONS, E91B(11) (11), 3489 - 3498, English
    [Refereed]
    Scientific journal

  • ワイヤレスセンサネットワークのためのデータ集約を考慮した部分起動メモリの電力削減効果に関する研究
    SAKAI Yasuharu, MATSUDA Takashi, IZUMI Shintaro, TAKEUCHI Takashi, FUJIWARA Hidehiro, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    Sep. 2008, 電子情報通信学会ソサイエティ大会, B-20-10, pp. 346, Japanese
    International conference proceedings

  • Augusto Foronda, Chikara Ohta, Hisashi Tamaki
    Jun. 2008, IEICE TRANSACTIONS ON COMMUNICATIONS, E91B(6) (6), 1952 - 1961, English
    [Refereed]
    Scientific journal

  • An Enhanced Proportional Fair Algorithm to Provide QoS over a Shared Wireless Link
    Augusto Foronda, Chikara Ohta, Hisashi Tamaki
    2008, 2008 INTERNATIONAL CONFERENCE ON ADVANCED TECHNOLOGIES FOR COMMUNICATIONS, PROCEEDINGS, 106 - 109, English
    [Refereed]
    International conference proceedings

  • Implementation of publish/subscribe system on wireless mesh networks - Word-mouth information distribution service
    Ken-ichiro Yagura, Yusuke Kato, Takayuki Kitada, Kazuhiro Yamaguchi, Yumi Takaki, Mitsuhiro Kuwano, Chikara Ohta
    2008, 2008 7TH ASIA-PACIFIC SYMPOSIUM ON INFORMATION AND TELECOMMUNICATION TECHNOLOGIES, 178 - +, English
    [Refereed]
    International conference proceedings

  • Impact of divided static random access memory considering data aggregation for wireless sensor networks
    Takashi Matsuda, Shintaro Izumi, Takashi Takeuchi, Hidehiro Fujiwara, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2008, 2008 7TH ASIA-PACIFIC SYMPOSIUM ON INFORMATION AND TELECOMMUNICATION TECHNOLOGIES, pp. 130-134, 115 - +, English
    [Refereed]
    International conference proceedings

  • Hop Count Aware broadcast algorithm with Random Assessment Delay Extension for wireless sensor networks
    Shintaro Izumi, Takashi Matsuda, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2008, 2008 7TH ASIA-PACIFIC SYMPOSIUM ON INFORMATION AND TELECOMMUNICATION TECHNOLOGIES, pp. 30-35, 207 - +, English
    [Refereed]
    International conference proceedings

  • Takashi Matsuda, Masumi Ichien, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    Dec. 2007, IEICE TRANSACTIONS ON COMMUNICATIONS, E90B(12) (12), 3410 - 3418, English
    [Refereed]
    Scientific journal

  • Augusto Foronda, Yuhi Higuchi, Chikara Ohta, Masahiko Yoshimoto, Yoji Okada
    Nov. 2007, IEICE TRANSACTIONS ON COMMUNICATIONS, E90B(11) (11), 3158 - 3169, English
    [Refereed]
    Scientific journal

  • 長波帯標準電波を用いた低電力センサーノードのための垂直統合設計
    OTAKE Yu, ICHIEN Masumi, TAKEUCHI Takashi, GION Akihiro, MIKAMI Shinji, FUJIWARA Hidehiro, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    Jul. 2007, 電子情報通信学会技術研究報告,ICD2007-49, Vol.107,No.163,pp.71-76, Japanese
    International conference proceedings

  • ワイヤレスセンサーネットワーク応用キャリアセンス機能を持つ433MHz帯、356-uW電圧増幅器
    LEE Hyeokjong, MIKAMI Shinji, TAKEUCHI Takashi, ICHIEN Masumi, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    Jul. 2007, 電子情報通信学会技術研究報告,ICD2007-50, Vol.107,No.163,pp.77-82, Japanese
    International conference proceedings

  • Takashi Matsuda, Masumi Ichien, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    Institute of Electronics, Information and Communication, Engineers, IEICE, 2007, IEICE Transactions on Communications, E90-B(12) (12), 3410 - 3418, English
    [Refereed]
    Scientific journal

  • A fair scheduling algorithm to improve stability region with zero-forcing beamforming for a multiuser MIMO wireless systems
    Augusto Foronda, Chikara Ohta, Hisashi Tamaki
    2007, 2007 FOURTH INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATION SYSTEMS, VOLS 1 AND 2, CD-Paper, 95 - 99, English
    [Refereed]
    International conference proceedings

  • Shinji Mikami, Takashi Takeuchi, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2007, Proceedings - 2007 IEEE Radio and Wireless Symposium, RWS, pp.447-450, 447 - 450, English
    [Refereed]
    International conference proceedings

  • A 356 mu W, 433-MHz, rail-to-rail voltage amplifier with carrier sensing function for wireless sensor networks
    Shinji Mikami
    2007, 2007 IEEE RADIO AND WIRELESS SYMPOSIUM, pp.451-454, 160 - 163, English
    [Refereed]
    International conference proceedings

  • Delay guarantee and service interval optimization for HCCA in IEEE 802.11e WLANs
    Yuhi Higuchi, Augusto Foronda, Chikara Ohta, Masahiko Yoshimoto, Yoji Okada
    2007, 2007 IEEE WIRELESS COMMUNICATIONS & NETWORKING CONFERENCE, VOLS 1-9, pp.00-00, 2082 - +, English
    [Refereed]
    International conference proceedings

  • Analysis of the statistical time-access fairness index under a scheduler exploiting multiuser diversity
    Fumio Ishizaki, Chikara Ohta
    2007, 2007 WIRELESS TELECOMMUNICATIONS SYMPOSIUM, CD-ROM, 176 - +, English
    [Refereed]
    International conference proceedings

  • Multipath routing using Isochronous medium access control with multi wakeup period for wireless sensor networks
    Takashi Matsuda, Takafumi Aonishi, Takashi Takeuchi, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2007, 2007 FOURTH INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATION SYSTEMS, VOLS 1 AND 2, pp.718-721, 796 - 799, English
    [Refereed]
    International conference proceedings

  • Shintaro Izumi, Takashi Matsuda, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2007, 2007 International Conference on Sensor Technologies and Applications, SENSORCOMM 2007, Proceedings, pp.76-81, 76 - 81, English
    [Refereed]
    International conference proceedings

  • Yu Otake, Masumi Ichien, Takashi Takeuchi, Akihiro Gion, Shinji Mikami, Hidehiro Fujiwara, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2007, 2007 International Conference on Sensor Technologies and Applications, SENSORCOMM 2007, Proceedings, pp.341-346, 341 - 346, English
    [Refereed]
    International conference proceedings

  • A fair scheduling algorithm to improve stability region with zero-forcing beamforming for a multiuser MIMO wireless systems
    Augusto Foronda, Chikara Ohta, Hisashi Tamaki
    2007, 2007 FOURTH INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATION SYSTEMS, VOLS 1 AND 2, pp. 16-19, 95 - 99, English
    [Refereed]
    International conference proceedings

  • Shinji Mikami, Takafumi Aonishi, Hironori Yoshino, Chikara Ohta, Hiroshi Kawaguchi, Masahiko Yoshimoto
    Oct. 2006, IEICE TRANSACTIONS ON COMMUNICATIONS, E89B(10) (10), 2741 - 2751, English
    [Refereed]
    Scientific journal

  • A New Scheduler to Guarantee Delay Bound with Bwidth Optimization for HCCA in IEEE 802.11e WLANs
    HIGUCHI Yuhi, OHTA Chikara, OKADA Youji, YOSHIMOTO Masahiko
    Jun. 2006, 電子情報通信学会技術研究報告, IN2006-28Vol.106 No.118pp.67-7, 67 - 72, Japanese
    Scientific journal

  • 定期情報収集型センサネットワークのためのRTS/CTS交換に基づくデータ送信スケジューリング
    MATSUDA Takashi, ICHIEN Masumi, MIKAMI Shinji, OHTA Chikara, KAWAGUCHI Hiroshi, YOSHIMOTO Masahiko
    One of challenging issues on the sensor networks is to extend lifetime of network system as a whole. In periodic data gathering applications, idle time occupies longer than transmission time in the state of a sensor node. Consequently, it is important to decrease wasteful power consumption during idle time. In this study, we propose a scheduling algorithm based on history of RTS/CTS exchange during setup phase. Scheduling the transmission during transfer phase enables each node to turn off its RF circuit during idle time. By tracing ongoing RTS/CTS exchange during data transfer phase, each node knows progress of data transfer process so that it can wait to receive packets for data aggregation. Simulation results show that system lifetime of our scheduling extends 220% longer than that of existing "power scheduling."
    一般社団法人電子情報通信学会, Apr. 2006, 電子情報通信学会技術研究報告, NS2006-7Vol.106No.14pp.25-28(14) (14), 25 - 28, Japanese

  • 送信電力制御による効率劣化の影響
    MIKAMI Shinji, TAKEUCHI Takashi, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    ワイヤレスセンターネットワークの長寿命化において送信電力はその重要な1つの方法として考えられる。従来研究においては、消費電力はO(d^n)(ここでdは最大通信距離、nはパス損失係数)で変化すると仮定されてきた。しかし、この仮定は送信効率が常に一定の場合において成り立つものであり、実際には送信効率は変動すると考えられる。そこで本稿では、送信器の最終段であるパワーアンプ、インピーダンス整合回路、アンテナをモデル化し,インピーダンス整合理論ならびに,典型的なA、C級パワーアンの実回路シミュレーションにより、送信効率の劣化が及ぼす影響を検討した。その結果、送信効率が劣化する場合、送信器の消費電力がO(d^r)([numerilal formulu])により変化することを明らかにした。 In order to extend available period of wireless sensor networks, transmission power control is regarded as one of the promising schemes. In most of previous research about transmission power control, it is assumed that a transmitter has power consumption of O(d^n), where d and n denote maximum communication distance and pass loss factor. This assumption substantially holds under the condition that the transmitter efficiency is always constant (efficiency-fixed model). In practice, however, the transmitter efficiency can vary with antenna-output power. In this paper, we show a transmitter with its efficiency degradation has power consumption of O(d^r), where [numerilal formulu] (efficiency degradation model). To do so, we model the final stage of transmitter including antenna as an integrated circuit of PA (power amplifier), impedance matching circuit and antenna impedance, and then analyze the model in two ways. The first analysis is based on matching theorem. The second analysis treats of a typical and realistic circuit for class-A and C power amplifiers, and also verify the analytical results by circuit simulations.
    一般社団法人電子情報通信学会, Apr. 2006, 電子情報通信学会技術研究報告, NS2006-4Vol.106No.14pp.13-16(14) (14), 13 - 16, Japanese

  • 製造ばらつきを考慮したセンサネットワークノード消費電力モデルの提案と評価
    TAKEUCHI Takashi, YOSHINO Hironori, ICHIEN Masumi, MATSUDA Takashi, MIKAMI Shinji, OHTA Chikara, KAWAGUCHI Hiroshi, YOSHIMOTO Masahiko
    ワイヤレスセンサネットワークでは、ライフタイムの拡大が最も重要な課題である。ネットワークのライフタイムを拡大するためには、システム全体の最適設計をしなければならない。設計したシステムを評価するために、シミュレータに実装可能なセンサノードの消費電力モデルが求められていた。本研究では、センサノードの消費電力モデルに、現在CMOS回路で問題となっている閾値電圧の製造ばらつきを導入した。従来モデルと比較すると、閾値電圧ばらつきを考慮した場合、消費電力がばらつき、平均消費電力が増大することが判明した。さらに、ネットワークシミュレータに実装し、ネットワークレベルで比較した。その結果、従来のモデルはばらつきのあるモデルよりもシステムライフタイムを長く見積もる傾向にあることがわかった。 We introduced manufacturing variation into a power model for a wireless sensor network node. Network protocols for wireless sensor networks such as media access control and routing should be evaluated in terms of life time as a whole system. In fact, there exists variation in power node-by-node due to the manufacturing variation. In the previous research, however, this effect has not been investigated at all since it has been supposed that all nodes have the same power. In this paper, we develop a more exact power model for sensor nodes, which we name the threshold-voltage variation model, considering threshold-voltage variation in a manufacturing process. A microprocessor and RF part are considered as hardware blocks in the model, which is then implemented to QualNet in order to evaluate the impact on the life time. The simulation results show that the conventional model overestimates the life time longer than our model.
    一般社団法人電子情報通信学会, Apr. 2006, 電子情報通信学会技術研究報告, NS2006-6Vol.106No.14pp.21-24(14) (14), 21 - 24, Japanese

  • センサネットワークのための長波帯標準電波時刻同期を用いた周期起動型MACの提案
    ICHIEN Masumi, TAKEUCHI Takashi, MIKAMI Shinji, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    本稿では,センサネットワークのためのメディアアクセス制御として,長波標準電波時刻同期を用いたマルチホップ通信可能なI-MAC(Isochronous-MAC)を提案する.I-MACはLow Power Listening方式をベースに,長波標準電波時刻同期によりノード全体が同じタイミングで起動する.受信ノードの起動時刻が予想できるため,LPLに比べてプリアンブル長を短くでき,消費電力を削減できる.本論文では,時刻同期に必要な消費電力オーバヘッドを考慮した解析モデルにより,起動周期,クロックドリフト,時刻同期頻度が消費電力に与える影響を調査した.その結果,LPLは,送信範囲内ノード数,データ送信頻度に対して最適な起動周期の感度が高く,起動周期の設定を注意深く選択する必要があるのに対し,I-MACは,起動周期の選択が容易であり,時刻同期に要する消費電力を考慮してもLPLに対して消費電力を低く抑えることができることを明らかにした. This paper proposes Isochronous-MAC (I-MAC), which utilizes low-frequency radio waves time synchronization for radio controlled clocks, for sensor networks. Using I-MAC, based on the Low Power Listening (LPL), all sensor nodes wake and listen channel periodically and synchronously. Since a sender can easily predict wakeup time of an intended receiver, it can shorten the length of preamble to make the receiver prepare for reception of the following data packet. In the paper, we use an analytical model to investigate the impact of the data transmission frequency, the number of neighboring nodes, the wakeup period, the clock drift, and the time-synchronization frequency on the power consumption for consideration of the power overhead to perform the time synchronization. Those results demonstrate that I-MAC allows determination of any arbitrary wakeup period without much difficulty, whereas LPL requires a much more careful setting of the wakeup period because its optimum wakeup period is sensitive to the frequency of data transmission as well as to the number of neighboring nodes. Therefore, I-MAC has a great potential to reduce the power consumption in most situations compared with LPL, in spite of the overhead to perform time synchronization.
    一般社団法人電子情報通信学会, Apr. 2006, 電子情報通信学会技術研究報告, NS2006-8Vol.106No.14pp.29-32(14) (14), 29 - 32, Japanese

  • センサネットワークのための集約率を考慮したGIT経路制御の評価
    AONISHI Takafumi, YOSHINO Hironori, MIKAMI Shinji, OHTA Chikara, KAWAGUCHI Hiroshi, YOSHIMOTO Masahiko
    センサネットワークのための経路制御の研究では, 完全集約が仮定されている場合が多くみられる.そのような仮定は, センサネットワークのアプリケーションを制約する.本稿では, GIT経路制御において集約効率がエネルギ消費に及ぼす影響を検討する.われわれは, 集約効率に応じた最適な集約点を選択することで, どの程度のエネルギ消費を削減できるのかに興味がある.本稿では, GITを改良したAGIT(Aggregation afficiency-aware GIT)方式を提案する.また, exploratory messageを抑圧するための方法として, minimum exploratory方式とhop exploratory方式を検討する.シミュレーション結果より, AGITはGITに比べてデータ転送時のエネルギ消費を削減できることを示す. In most research work for sensor network routings, perfect aggregation has been assumed. Such an assumption might limit the application of the wireless sensor networks. We address the impact of aggregation efficiency on energy consumption in the context of GIT routing. Our question is the extent to which energy consumption can decrease compared to the original GIT. In this paper, we propose an improved GIT : "aggregation efficiency-aware routing", or AGIT. We also consider two suppression schemes for exploratory messages : "minimum exploratory" and "hop exploratory." Our simulation results show that the AGIT saves the energy consumption of the data transmission compared to the original GIT.
    一般社団法人電子情報通信学会, Apr. 2006, 電子情報通信学会技術研究報告, NS2006-9Vol.106No.14pp.33-36(357) (357), 37 - 40, Japanese

  • Min-Te Sun, Ten-Hwang Lai, Yu Wang, Chin-Tser Huang, Saad Biaz, Richard Brooks, Sheikh Iqbal Ahamed, Phillip Bradford, Chung-Kuo Chang, Cho-Yu Chiang, Jen-Yao Chung, Xinwen Fu, Xiaoyan Hong, Jianping Jiang, Ying Jing, Sandeep Kulkarni, Qun Li, Masakatsu Ogawa, Chikara Ohta, Bin Wang, Wenye Wang
    2006, Proceedings of the International Conference on Parallel Processing Workshops, English
    [Refereed]
    International conference proceedings

  • Isochronous MAC using long-wave standard time code for wireless sensor networks
    Masumi Ichien, Takashi Takeuchi, Shinji Mikami, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2006, 2006 FIRST INTERNATIONAL CONFERENCE ON COMMUNICATIONS AND ELECTRONICS, 172 - +, English
    [Refereed]
    International conference proceedings

  • A New Framework to Provide Quality of Service in MPLS Network
    Augusto Foronda, Leandro C. Pykosz, Chikara Ohta, Masahiko Yoshimoto
    2006, PROCEEDINGS OF THE IEEE INTERNATIONAL TELECOMMUNICATIONS SYMPOSIUM, VOLS 1 AND 2, 1005 - +, English
    [Refereed]
    International conference proceedings

  • Impact of aggregation efficiency on GIT routing for wireless sensor networks
    Takafumi Aonishi, Takashi Matsuda, Shinji Mikami, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2006, 2006 INTERNATIONAL CONFERENCE ON PARALLEL PROCESSING WORKSHOPS, PROCEEDINGS, pp.00-00, 151 - +, English
    [Refereed]
    International conference proceedings

  • A power-variation model for sensor node and the impact against life time of wireless sensor networks
    Takashi Matsuda, Takashi Takeuchi, Hironori Yoshino, Masumi Ichien, Shinji Mikami, Hiroshi Kawaguchi, Chikara Ohta, Masahiko Yoshimoto
    2006, 2006 FIRST INTERNATIONAL CONFERENCE ON COMMUNICATIONS AND ELECTRONICS, pp.106-111, 106 - +, English
    [Refereed]
    International conference proceedings

  • センサネットワークのための集約率を考慮したGIT経路制御の評価
    AONISHI Takafumi, YOSHINO Hironori, MIKAMI Shinji, OHTA Chikara, KAWAGUCHI Hiroshi, YOSHIMOTO Masahiko
    センサネットワークのための経路制御の研究では,完全集約が仮定されている場合が多くみられる.そのような仮定は,センサネットワークのアプリケーションを制約する.本稿では,GIT経路制御において集約効率がエネルギ消費に及ぼす影響を検討する.われわれは,集約効率に応じた最適な集約点を選択することで,どの程度のエネルギ消費を削減できるのかに興味がある.本稿では,GITを改良したAGIT(Aggregation efficiency-aware GIT)方式を提案する.また,exploratory messageを抑圧するための方法として,hop exploratory方式を検討する.シミュレーション結果より,AGITはGITに比べてデータ転送時のエネルギ消費を削減できることを示す. In most research work for sensor network routings, perfect aggregation has been assumed. Such an assumption might limit the application of the wireless sensor networks. We address the impact of aggregation efficiency on energy consumption in the context of GIT routing. Our question is the extent to which energy consumption can decrease compared to the original GIT. In this paper, we propose an improved GIT: "aggregation efficiency-aware routing", or AGIT. We also consider a suppression scheme for exploratory messages: "hop exploratory." Our simulation results show that the AGIT saves the energy consumption of the data transmission compared to the original GIT.
    一般社団法人電子情報通信学会, Oct. 2005, 電子情報通信学会技術研究報告;NS2005-108, Vol.105; No.357; pp.37-40(14) (14), 33 - 36, Japanese

  • ワイヤレスセンサノードのための送信電力制御におけるインピーダンス不整合の影響
    MIKAMI Shinji, TAKEUCHI Takashi, OHTA Chikara, KAWAGUCHI Hiroshi, YOSHIMOTO Masahiko
    Sep. 2005, 2005年電子情報通信学会ソサイエティ大会;B-5-148, p.148, Japanese
    International conference proceedings

  • Index-server optimization for P2P file sharing in mobile ad hoc networks
    C Ohta, ZH Ge, Y Guo, J Kurose
    2004, GLOBECOM '04: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6, 未記入, 960 - 966, English
    [Refereed]
    International conference proceedings

  • Rescue System Based on Location Aware Information Exchange in Mobile AdHoc Network
    NIKOLOV Andrey, TSUBOTA Shigeru, WATANABE Terumasa, OHTA Chikara, UEHARA Kuniaki
    2003, Proc. of the 2003 International Workshop on Mobile Systems, E-Commerce and Agent Technology (MSEAT'2003),, pp.325-330, English
    [Refereed]
    International conference proceedings

  • Moment Calculating Algorithm for Busy-period of Discrete-time Finite-capacity M/G/1 Type Queue
    OHTA Chikara, MORII Masakatu
    In this paper, we propose an algorithm to calculate the higher moments of the busy period length of a discretetime M/G/1 type queue with finite buffer. The queueing model has a level-dependent transition probability matrix. Our algorithm is given as a set of recursive formulas which are derived from the relationship among the generating function matrices of the fundamental period. As an example of our algorithm, we provide an approximate analysis of a HOL (Head Of Line) priority control queue.
    The Institute of Electronics, Information and Communication Engineers, Jan. 2002, IEICE transactions on communications, 85(1) (1), 293 - 304, English

  • SHIRAISHI Yoshiaki, SHIRAKAWA Yoshinori, OHTA Chikara, SONE Naoto, MORII Masakatu
    In the Internet, the IXP (Internet Exchange Point) /s tend to be congested since all traffic must go through the IXP's if the ISP (Internet Service Provider) 's belong to the different upper ISP's. In particular, this problem is serious in Japan since we have only a few IXP's. To ease this problem, we focus on the HTTP traffic exchanged among the neighboring ISP's since the web browsing causes major traffic in the Internet. In this paper, we provide a structure of regional HTTP-IXP and its experimental results. Our HTTP-IXP system aims to reduce the backborn traffic with comparatively low cost by exchanging the regional HTTP traffic via HTTP cash server. Our experimental results show that the backborn traffic can be reduced without the degradation of any user QoS (Quality of Service).
    THE INSTITUTE OF SYSTEMS, CONTROL AND INFORMATION ENGINEERS (ISCIE), Apr. 2000, Transactions of the Institute of Systems, Control and Information Engineers, 13(4) (4), 168 - 178, Japanese
    Scientific journal

  • Chikara Ohta, Tetsuya Takine, Masayuki Murata
    Feb. 2000, International Journal of Communication Systems, 13(1) (1), 51 - 77
    [Refereed]
    International conference proceedings

  • Phase Assignment Algorithm Based on Traffic Measurement for Real-Time MPEG Sources in ATM Networks
    TOJO Shinya, ISHIZAKI Fumio, OHTA Chikara
    This paper proposes a phase assignment algorithm "Silent Wave Algorithm (SWA)" for real-time MPEG traffic in ATM networks. Our algorithm decides when a new MPEG source should begin to transmit based on its notification parameters and traffic measurement of ongoing connections. Simulation results show that it is hard to accommodate MPEG traffic effectively without any control of phase assignment. On the other hand, the SWA can provide better QOS and improve the network utilization.
    The Institute of Electronics, Information and Communication Engineers, Dec. 1999, IEICE transactions on communications, 82(12) (12), 2073 - 2080, English

  • Phase Assignment Control for Periodic and Bursty Sources in ATM Networks
    ISHIZAKI Fumio, OHTA Chikara
    In order to accommodate periodic and bursty sources into ATM networks effectively, we propose phase assignment control (PAC), which actively controls the phase of the new connection at its connection setup phase. To realize PAC, we develop an algorithm to find a good phase of the new connection in a short time. Simulation results show that the PAC can improve the system performance.
    The Institute of Electronics, Information and Communication Engineers, Jul. 1999, IEICE transactions on communications, 82(7) (7), 1064 - 1068, English

  • Output process of shaper and switch with self-similar traffic in ATM networks
    OHTA Chikara, ISHIZAKI Fumio
    This paper studies how the self-similarity of traffic changes through shaper (buffered leaky bucket) and switch in ATM networks by numerical experiments. Further the applicability of CAC algorithm to shaped self-similar traffic is also investigated. Numerical experiments show self-similarity of total output traffic from shapers and switch is kept while connection-wise self-similarity is broken.
    The Institute of Electronics, Information and Communication Engineers, Oct. 1998, IEICE Trans. on Commun., 81(10) (10), 1936 - 1940, English

  • A Packet Distribution Experiment of Still and Moving Images over the Internet : The Project of Awadance Internet Live '96 and '97
    MORII Masakatu, SHIRAISHI Yoshiaki, SONE Naoto, IWATA Ken-ich, OHTA Chikara, OIE Takahiro
    画像電子学会, Jun. 1998, The Journal of the Institute of Image Electronics Engineers of Japan, 27(3) (3), 253 - 262, Japanese

  • Shinya Tojo, Fumio Ishizaki, Chikara Ohta
    Institute of Electrical and Electronics Engineers Inc., 1998, Proceedings - 7th International Conference on Computer Communications and Networks, ICCCN 1998, 1998-, 178 - 182, English
    International conference proceedings

  • Fumio Ishizaki, Chikara Ohta
    1998, International Conference on Communications - Proceedings, 3, 1510 - 1514, English
    [Refereed]
    International conference proceedings

  • Bounded-delay and loss-free guarantees for real-time video in integrated services packet networks
    Chikara Ohta, Tetsuya Takine, Masayuki Murata
    1998, Conference Record / IEEE Global Telecommunications Conference, 1, 477 - 483
    [Refereed]
    Scientific journal

  • Comparison of Cell Transfer Quality Control for Multimedia Traffic in ATM Networks
    OHTA Chikara, SATO Katsunori, ONOZATO Yoshikuni
    This paper compares three cell transfer quality control schemes, namely HPS, DAS and ORS, which integrate a preventive congestion control and a reactive congestion control in ATM switch. Simulation results showed that ORS achieves the largest network utilization, and HPS provides enough large throughput compared with DAS only when many VBR connections are multiplexed.
    The Institute of Electronics, Information and Communication Engineers, Aug. 1997, IEICE transactions on communications, 80(8) (8), 1273 - 1277, English

  • Chikara Ohta, Miki Yamamoto, Hiromasa Ikeda
    John Wiley and Sons Inc., 1997, Electronics and Communications in Japan, Part I: Communications (English translation of Denshi Tsushin Gakkai Ronbunshi), 80(2) (2), 44 - 54, English
    Scientific journal

  • RATE-Based Congestion Control with Little Influence of the Number of Virtual Channels
    UENO Yoshiaki, OHTA Chikara, YAMAMOTO Miki, OKADA Hiromi, IKEDA Hiromasa
    Interval-based Approachのレートベース型ふくそう制御方式を改良し, 多重VC数の影響が少ないMAIMD方式を提案した. シミュレーション結果から, 提案方式が多重VC数によらず大きなパワーを示す制御パラメータを有することがわかった.
    The Institute of Electronics, Information and Communication Engineers, Aug. 1996, The transactions of the Institute of Electronics, Information and Communication Engineers, 79(8) (8), pp.585 - 586, Japanese

  • Feedback Type Rate-Based Congestion Control with Adaptive Parameter
    OHTA Chikara, YAMAMOTO Miki, IKEDA Hiromasa
    ATM-LANにおけるABRサービスクラスのトラヒック制御手法としてフィードバック型レート制御方式がある.本論文では,送出レートを加算増加,乗算減少させる2値フィードバック型レート制御方式において,ボトルネックキューを経由するコネクション数が増加するとグッドプットが低下する可能性があることを示し,この問題を解決する方法として,ボトルネックノードにおける待ち行列長の変動のピーク値から,伝送中のコネクション数の増減を検知し,送信端末の送出レートの増加幅を動的に変更する"適応パラメータを用いたフィードバック型レート制御方式"を提案している.シミュレーション結果は,提案方式がボトルネックノードを共有するコネクション数にかかわらず良好なパワー特性を示すことを明らかにしている.
    The Institute of Electronics, Information and Communication Engineers, Nov. 1995, The Transactions of the Institute of Electronics,Information and Communication Engineers B-(0xF9C1), 78(11) (11), 642 - 651, Japanese

  • A VIRTUAL STM TRANSMISSION METHOD BASED ON ATM NETWORK
    N KAMIYAMA, C OHTA, H TODE, M YAMAMOTO, H OKADA
    Jun. 1995, ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS, 78(6) (6), 13 - 29, English
    [Refereed]
    Scientific journal

  • Analysis of a Discrete-Time Finite-Buffer Single Server Queue with Correlation in Both Arrival Process and Service Process
    OHTA Chikara, TODE Hideki, YAMAMOTO Miki, OKADA Hiromi
    本論文ではATMに親和性の高い離散時間環境において,到着過程だけでなく,サービス過程にも相関性のある有限容量単一サーバ待ち行列としてD-BMAP / D-MAP / 1 / Nを解析し,定常状態確率分布,廃棄率,および稼働期間,システム滞留時間,退去間隔の確率母関数を得ている.また本待ち行列モデルの応用例としてバッファドリーキーバケットを考え,数値例を示している.リーキーバケットに代表されるような,ATM網でのトラヒック制御手法の中には,そのセル送出規律に相関性を有するものがあり,これらのシステムを待ち行列モデルにより性能評価する場合は,到着過程だけでなくトラヒック制御によるサービス過程の相関性も考慮する必要がある.本待ち行列モデルでは,到着過程にD-BMAPを,サービス過程にD-MAPを仮定している.Blondiaらによって提案されたD-BMAPは,D-MAPを集団到着に拡張したものであり,その重畳過程もまたD-BMAPで表現できる.またD-MAPは,MMBP等の相関性を有する到着過程だけでなく,リーキーバケットなどのトラヒック制御システムのセル送出規律も表現できる.従って,サービス過程をD-MAPとすることにより,到着過程だけでなくトラヒック制御によるサービス過程の相関性も反映させた性能評価が可能となる.
    The Institute of Electronics, Information and Communication Engineers, Aug. 1994, The Transactions of the Institute of Electronics,Information and Communication Engineers B-(0xF9C1), 77(8) (8), 493 - 505, Japanese

  • A Virtual STM Transmission Method Based on ATM Network
    KAMIYAMA Noriaki, OHTA Chikara, TODE Hideki, YAMAMOTO Miki, OKADA Hiromi
    本論文では,ATM網においてセルの無廃棄,網内遅延無変動を実現する方法として,ATM交換基盤に回線交換における時間スイッチの概念を導入した新しい伝送方式(Q-STM:Quasi-Synchronous Transfer Mode)を考え,その交換機構造と呼設定方法を提案する.本方式では,時間スイッチの導入によりATM交換基盤における出力端子競合が原理的に発生せず,また,ある一定量のバッファを配置することによりATM交換機の出力端子におけるバッファあふれによるセル廃棄を完全に防止できる.更に,時間交換単位となるサブフレームを新たに導入し,フレーム構成として,フレーム,サブフレーム,スロットの3階層構造をとることにより,割当て帯域の柔軟性を保持しつつ,サブフレームを導入しない場合と比較して時間交換に伴う遅延を減少させる.また,ATM交換機を基盤としているため,フレームに束縛されない通常のATMセルをフレーム内の空きスロットにより伝送,ATM交換することにより,ATMの特徴である統計多重効果による回線の有効利用を図る.シミュレーションにより,通常ATMセル品質の基本特性を明らかにした.
    The Institute of Electronics, Information and Communication Engineers, May 1994, The Transactions of the Institute of Electronics,Information and Communication Engineers B-(0xF9C1), 77(5) (5), 353 - 365, Japanese

  • QUASI-STM TRANSMISSION METHOD BASED ON ATM NETWORK
    N KAMIYAMA, C OHTA, H TODE, M YAMAMOTO, H OKADA
    1994, 1994 IEEE GLOBECOM - CONFERENCE RECORD, VOLS 1-3, AND COMMUNICATIONS THEORY MINI-CONFERENCE RECORD, 1808 - 1814, English
    [Refereed]
    International conference proceedings

  • A PROPOSAL OF QUASI-STM TRANSMISSION METHOD IN ATM-BASED NETWORK
    H TODE, N KAMIYAMA, C OHTA, M YAMAMOTO, H OKADA
    Jul. 1993, IEICE TRANSACTIONS ON COMMUNICATIONS, E76B(7) (7), 719 - 722, English

  • PEAK RATE REGULATION SCHEME FOR ATM NETWORKS AND ITS PERFORMANCE
    C OHTA, H TODE, M YAMAMOTO, H OKADA, Y TEZUKA
    1993, IEEE INFOCOM 93 : THE CONFERENCE ON COMPUTER COMMUNICATIONS, PROCEEDINGS, VOLS 1-3, 6a.4, pp.680-689, 680 - 689, English
    International conference proceedings

  • TRAFFIC CONTROL SCHEME FOR INTERCONNECTION OF FDDI NETWORKS THROUGH ATM NETWORK
    M YAMAMOTO, T HIRATA, C OHTA, H TODE, H OKADA, Y TEZUKA
    1993, IEEE INFOCOM 93 : THE CONFERENCE ON COMPUTER COMMUNICATIONS, PROCEEDINGS, VOLS 1-3, 411 - 420, English
    [Refereed]
    International conference proceedings

■ MISC
  • Ohta Chikara
    The Institute of Electronics, Information and Communication Engineers, 01 Dec. 2018, IEICE Communications Society Magazine, 12(3) (3), 229 - 233, Japanese

  • 高木 由美, 南 浩明, 木下 敦志, 太田 能, 玉置 久
    神戸大学都市安全研究センター, Mar. 2015, 神戸大学都市安全研究センター研究報告, 19(19) (19), 232 - 240, Japanese
    Link to Kobe Univ. Repository (Kernel)

  • 藤田 圭佑, 高木 由美, 太田 能, 玉置 久, 有木 康雄
    神戸大学都市安全研究センター, Mar. 2013, 神戸大学都市安全研究センター研究報告, 17(17) (17), 269 - 278, Japanese
    Link to Kobe Univ. Repository (Kernel)

  • パレート最適ネットワーク実現のためのユーザ・資源管理アプリケーションデモシステムの開発—Development of a demonstration system for User and Resource Management Technologies towards Pareto-optimal Wired-wireless Networks
    矢守 恭子, 太田 能, 長谷川 剛
    東京 : 電子情報通信学会, 25 Jan. 2013, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 112(414) (414), 1 - 4, Japanese

  • 山里 敬也, 佐波 孝彦, 塩田 茂雄, 太田 能
    一般社団法人 電子情報通信学会, 2013, 電子情報通信学会 通信ソサイエティマガジン, 6(3) (3), 222 - 230, Japanese

  • パレート最適ネットワーク実現のためのユーザ・資源管理アプリケーション—User and Resource Management Technologies towards Pareto-optimal Wired-wireless Networks—情報ネットワーク
    太田 能, 長谷川 剛, 新熊 亮一
    東京 : 電子情報通信学会, Oct. 2012, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 112(230) (230), 39 - 44, Japanese

  • BT-4-5 Network Management and Control Technologies for Pareto Optimal Network
    Yamori Kyoko, Ohta Chikara, Shinkuma Ryoichi, Hasegawa Go, Murase Tutomu, Oguchi Masato
    The Institute of Electronics, Information and Communication Engineers, 06 Mar. 2012, Proceedings of the IEICE General Conference, 2012(2) (2), "SS - 91"-"SS-92", Japanese

  • パネル討論 無線・有線統合環境におけるパレート最適ネットワーク実現のためのユーザおよび資源管理・制御機構—Panel Discussion : Management and Control of User and Resource toward Pareto-optimal Wireless and Wired Networks—ソフトウェア無線
    太田 能, 長谷川 剛, 新熊 亮一
    東京 : 電子情報通信学会, Jan. 2012, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 111(417) (417), 37 - 42, Japanese

  • EGUCHI Koji, YASUMURA Yoshiaki, NAKAMURA Masahide, TAKIGUCHI Tetsuya, OHTA Chikara, LUO Zhiwei
    Japanese Society for Engineering Education, 2008, Proceedings of Annual Conference of Japanese Society for Engineering Education, 2008, 22 - 23, Japanese

  • Horigami Shinji, Ohta Chikara, Tamaki Hisashi
    模型自動車のコース走行における速度調節・操舵決定方法を獲得することを目的とし，まず模型自動車の運動特性をモデル化し，車両シミュレータを作成する．続いて，車両の速度調節・操舵の決定方法をシミュレータに実装し，シミュレーションベースで実験を行う．その結果より速度調節・操舵の決定方式の有効性・可能性を検討する．
    The Institute of Systems, Control and Information Engineers, 2008, Proceedings of the Annual Conference of the Institute of Systems, Control and Information Engineers, SCI08, 297 - 297, Japanese

  • OHTA Chikara, NAKATANI Hiromasa
    THE INSTITUTE OF SYSTEMS, CONTROL AND INFORMATION ENGINEERS, 2004, SYSTEMS, CONTROL AND INFORMATION, 48(2) (2), 70 - 71, Japanese

  • Development of Network Application using JGN and Construction of Internet Access Network using Distributed Wireless Packet Networks
    Ohta Chikara, Mohri Masami, Morii Masakatsu
    The University of Tokushima, 2001, Scientific papers of Faculty of Engineering, Tokushima University, 46, 5, Japanese

  • 小野 功, 太田 能, 泓田 正雄, 伊藤 拓也, 越智 洋司, 毛利 公美
    公益社団法人 日本工学教育協会, 2000, 工学・工業教育研究講演会講演論文集, 2000(0) (0), 325 - 328, Japanese

■ Books And Other Publications
  • 電子情報通信学会通信ソサイエティマガジン
    TAKAKI Yumi, OHTA Chikara, KANEDA Shigeru, TAKAI Mineo
    Joint work, 電子情報通信学会通信ソサイエティ, Jun. 2009, Japanese
    Scholarly book

■ Lectures, oral presentations, etc.
  • Indoor Localization Using Router-to-Router RSSI and Transfer Learning for Dynamic Environments
    Liuyi Yang, Patrick Finnerty, Chikara Ohta
    IEICE Network System, Oct. 2024, English
    Oral presentation

  • Efficient Policy Retrieval for Attribute-Based Access Control on Ethereum
    Shota Kuroki, Patrick Finnerty, Chikara Ohta
    IEICE the 2024 General Conference, Mar. 2024, Japanese
    Oral presentation

  • Development of regional data sharing edge application considering uneven distributions of mobile clients
    Tomio Kamada, Yuma Yamashita, Kazuhiro Fujisawa, Shota Uneno, Patrick Finnerty, Chikara Ohta
    IEICE the 2024 General Conference, Mar. 2024, Japanese
    Oral presentation

  • A Study on Pedestrian Map for Vehicle to Vehicle Blind Spot Information Sharing
    Nobutaka FUKUDA, Naoko Enami, Tomio Kamada, Patrick Finnerty, Chikara Ohta
    IEICE the 2024 General Conference, Mar. 2024, Japanese
    Oral presentation

  • A Study of Admission Control Optimization Using Ising Machines for Non-Orthogonal Multiple Access Wireless Systems
    Hiroto NAKANO, Patrick Finnerty, Chikara Ohta, Fumio Ishizaki
    IEICE Technical Committee, Information Network, Dec. 2023, Japanese
    Oral presentation

  • Research and Development on Packet Scheduling for Wireless Harness
    Chikara Ohta, Hajime Migita, Yuki Nakagoshi, Patrick Finnerty, Makoto Okuhara, Nobuyuki Kurioka, Satoru Shimizu, Makoto Usui
    Academic eXchange for Information Environment and Strategy (AXIES), Security ICT, Nov. 2023, Japanese
    [Invited]
    Invited oral presentation

  • Configurable testbed for low-latency edge applications
    Shota Uneno, Patrick Finnerty, Tomio Kamada, Chikara Ohta
    IEICE the 2023 Society Conference, Sep. 2023, Japanese
    Oral presentation

  • Research and Development of Integrated Wire/Wireless Communications Technology for Light-weight In-vehicle Harness
    Hajime Migita, Makoto Takenaka, Patrick Finnerty, Chikara Ohta, Makoto Okuhara, Nobuyuki Kurioka, Satoru Shimizu, Makoto Usui
    IEICE the 2023 Society Conference, Sep. 2023, Japanese
    [Invited]
    Invited oral presentation

  • Topic Assignment Optimization Using Annealing Machines in Distributed Publish-Process-Subscribe Systems
    Ryoma Minakata, Patrick Finnerty, Chikara Ohta, Fumio Ishizaki
    IEICE Technical Committee, Network Systems, Jun. 2023, Japanese
    Oral presentation

  • A Migration Method of OpenFlow Controller Considering Both Transmission Delay and Load Balancing
    Songyi Zhou, Sho Hiraiishi, Patrick Finnerty, Chikara Ohta, Fumio Ishizaki
    IEICE Technical Committee, Network Systems, Jun. 2023, Japanese
    Oral presentation

  • Research and development of wired/wireless cooperative communication technology to reduce the weight of in-vehicle harnesses
    Hajime Migita, Makoto Takenaka, Patrick Finnerty, Chikara Ohta, Makoto Okuhara, Nobuyuki Kurioka, Satoru Shimizu, Makoto Usui
    IEICE Technical Committee, Information Network, May 2023, Japanese
    [Invited]
    Invited oral presentation

  • Study on minimal frame scheduling for in-vehicle UWB wireless communications
    Hajime Migita, Makoto Takenaka, Patrick Finnerty, Chikara Ohta
    IEICE the 2023 General Conference, Mar. 2023, Japanese
    Oral presentation

  • Evaluation of UWB communication feasibility to realize in-vehicle harnessless
    Makoto Okuhara, Nobuyuki Kurioka, Chikara Ohta
    IEICE the 2023 General Conference, Mar. 2023, Japanese
    Oral presentation

  • Localization of grazing cattle by dead reckoning using Kalman filter and Rauch-Tung-Striebel smoother
    Satoshi Wakana, Takenao Ohkawa, Mizuka Komatsu, Chikara Ohta, Kenji Oyama
    The 85th Natonal Convetion of IPSJ, Mar. 2023, Japanese
    Oral presentation

  • Research and Development on Packet Scheduling for Wireless Harness
    Chikara Ohta, Hajime Migita, Makoto Takenaka, Makoto Okuhara, Patrick Finnerty, Tomio Kamada
    Academic eXchange for Information Environment and Strategy (AXIES) SIG-HQSICT, Nov. 2022, Japanese
    Oral presentation

  • Evaluation of UWB communication feasibility to realize in-vehicle harnessless
    Makoto Okuhara, Chikara Ohta, Nobuyuki Kurioka
    2022 IEICE Society Conference, Sep. 2022, Japanese
    Oral presentation

  • A study on cluster optimization in wireless sensor networks based on linear programming
    Sidi Mohamed, Mohi Dine, Patrick Finnerty, Tomio Kamada, Chikara Ohta
    SCIE, Proc. SCI2022, May 2022, Japanese

  • Optimization and Implementation Evaluation of Polling Scheduling for In-vehicle UWB Communications
    Chikara Ohta, Taiyo Tanaka, Hajime Migita, Shuji Yamaguchi, Makoto Takenaka, Patrick Finnerty, Tomio Kamada
    SCIE, Proc. SCI2022, May 2022, Japanese

  • Optimization of Polling Scheduling for In-vehicle UWB Wireless Communications
    Hajime Migita, Taiyo Tanaka, Shuji Yamaguchi, Makoto Takenaka, Patrick Finnerty, Tomio Kamada, Chikara Ohta
    IEICE, Proc. the 2022 IEICE General Conference, Mar. 2022, Japanese

  • Implementation and Evaluation of Polling Scheduling for In-vehicle UWB Wireless Communications
    Taiyo Tanaka, Hajime Migita, Shuji Yamaguchi, Makoto Takenaka, Patrick Finnerty, Tomio Kamada, Chikara Ohta
    IEICE, Proc. the 2022 IEICE General Conference, Mar. 2022, Japanese

  • Latency reduction of nearby notification in a distributed publish-process-subscribe system for edge computing
    Ryota Matsumoto, Tomio Kamada, Patrick Finnerty, Chikara Ohta
    IEICE, Proc. the 2022 IEICE General Conference, Mar. 2022, Japanese

  • Prototype of a Monitoring System for Firefighter’s Location and Environmental Information
    Taiki Kitashouji, Shigeru Kashihara, Chikara Ohta, Atsushi Yamamoto
    IEICE, Proc. the 2022 IEICE General Conference, Mar. 2022, Japanese

  • Evaluating the Effects of Different Handover Algorithms for Het-Nets Using Petri Nets
    Zhiyi Zhu, Chikara Ohta, Tomio Kamada, Eiji Takimoto, Junjun Zheng
    IEICE Technical Report, Network Systems, Jan. 2022, English

  • Basic Study on Integrated Wire/Wireless Communications Technology for Light-weight In-vehicle Harness
    Chikara Ohta, Makoto Okuhara, Nobyuki Kurioka, Satoru Shimizu, Kazushi Sakuma
    Proc. of Kansai-section Joint Convention of Institutes of Electrical Engineering, Proc. of Conference, Dec. 2021, Japanese

  • 車載ハーネスの軽量化を実現する有線/無線連携通信技術の研究開発の概要紹介
    太田 能, 奥原 誠, 栗岡 伸行, 清水 聡, 佐久間 和司
    大学ICT推進協議会 高品質・セキュリティICT部会, Nov. 2021, Japanese

  • Introduction of Continuous Query into Distributed Key-Value Store with Explicit Cache Rules
    Ryo Machida, Tomio Kamada, Patrick Finnerty, Chikara Ohta
    IEICE, Proc. the 2021 IEICE Society Conference, Sep. 2021, Japanese

  • Research and Development of Integrated Wire/Wireless Communications Technology for Light-weight In-vehicle Harness
    Chikara Ohta, Makoto Okuhara, Nobyuki Kurioka, Satoru Shimizu, Kazushi Sakuma
    IEICE, Proc. the 2021 IEICE Society Conference, Sep. 2021, Japanese

  • A Study on Application of Quantum Annealing for NOMA Packet Scheduling
    Sho Nakata, Patrick Finnerty, Tomio Kamada, Chikara Ohta, Fumio Ishizaki
    IEICE, Proc. the 2021 IEICE Society Conference, Sep. 2021, Japanese

  • A Study on Radio Resource Allocation for LTE-V2X Sidelink
    Daigo Yasuda, Patrick Finnerty, Tomio Kamada, Chikara Ohta
    IEICE, Proc. the 2021 IEICE Society Conference, Sep. 2021, Japanese

  • Localization of Grazing Cattle Based on RSSI Considering Connectivity between Nodes
    Satoshi Wakana, Takenao Ohkawa, Chikara Ohta, Kenji Oyama
    Proc of IEICE/IPSJ Forum on Information Technology (FIT), Aug. 2021, Japanese

  • RNN-Based Behavioral Classification of Cattle Using Data from Collar Device
    Shunnosuke Ueda, Takenao Ohkawa, Chikara Ohta, Kenji Oyama
    Proc of IEICE/IPSJ Forum on Information Technology (FIT), Aug. 2021, Japanese

  • Experience in testing MPI+Java parallel and distributed programs with Junit
    Patrick Finnerty, Yoshiki Kawanishi, Tomio Kamada, Chikara Ohta
    IJPS, Proc. of Summer United Workshops on Parallel, Distributed and Cooperative Processing (SWoPP2021), Jul. 2021

  • Position Tracking using Low Power Radio for Extraction of Interaction among Grazing Cattle
    Chikara Ohta, Takahiro Yamanishi, Takuto Jikyo, Tomio Kamada, Takenao Ohkawa, Kenji Oyama, Takaharu Yaguchi, Ryo Nishide
    Proc. the 8th Korea-Japan Joint Workshop on Complex Communication Sciences, Dec. 2020, English
    [Invited]

  • Collaborative Caching for Pub/Sub System in Edge Computing
    TANAKA Tomoya, Tsutano Takumi, KAMADA Tomio, OHTA Chikara
    IEICE General Conference 2020, Mar. 2020, Japanese
    Oral presentation

  • Position Tracking using Low Power Radio for Extraction of Interaction among Grazing Cattle
    OHTA Chikara, YAMANISHI TAKAHIRO, JIKYO Takuto, KAMADA Tomio, OHKAWA Takenao, OYAMA Kenji, YAGUCHI Takaharu, NHISHIDE Ryo
    The 8th Korea-Japan Joint Workshop on Complex Communication Sciences, Jan. 2020, English
    [Invited]
    Keynote oral presentation

  • A study on outdoor localization method using bidirectional LSTM based on time series of received signal strength from low power wireless tags
    Takahiro Yamanishi, Takuto Jikyo, Tomio Kamada, Chikara Ohta, Ryo Nishide, Kenji Oyama, Takaharu Yaguchi, Takenao Ohkawa
    The First International Workshop on Control, Communication, and Multimedia 2019, Dec. 2019, English, Yangon, Myanmar, International conference
    Poster presentation

  • Position tracking using low power radio for analyzing interaction among grazing cattle
    OHTA Chikara, OHKAWA Takenao, OYAMA Kenji
    IEICE Technical Committee on Radio Communication Systems, Jul. 2019
    [Invited]
    Invited oral presentation

  • Position tracking using low power radio for analyzing interaction among grazing cattle
    太田 能, 大川 剛直, 大山 憲二
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Jul. 2019, Japanese, 電子情報通信学会

  • Experiments for Detection of Handheld Game Console by UAV with Wi-Fi Sensing Function
    KASHIHARA Shigeru, YAMAMOTO Atsushi, MATSUZAKI Kenta, MIYAZAKI Kosei, SEKI Tomoya, URAKAWA Go, FUKUMOTO Masahiro, OHTA Chikara
    IEICE SeMI, May 2019, Japanese, IEICE Sensor Networks and Mobile Intelligence, Amami-shi Syakai Fukushi Center, Domestic conference
    Oral presentation

  • 省電力無線タグ受信電力に基づく時系列を考慮した深層学習による屋外位置推定
    YAMANISHI Takahiro, JIKYO Takuto, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara, NISHIDE Ryo, OYAMA Kenji, OHKAWA Takenao
    電子情報通信学会総合大会, Mar. 2019, Japanese, 電子情報通信学会, 新宿区, Domestic conference
    Oral presentation

  • 省電力無線タグのモデルベース受信電力推定データを用いた深層学習に基づく屋外位置推定方式に関する一検討
    JIKYO Takuto, YAMANISHI Takahiro, TAKAKI Yumi, OHTA Chikara, OHKAWA Takenao, NISHIDE Ryo, OYAMA Kenji, KAMADA Tomio
    電子情報通信学会総合大会, Mar. 2019, Japanese, 電子情報通信学会, 新宿区, Domestic conference
    Oral presentation

  • 車両間情報共有による歩行者検知に関する一検討
    ASANO Kou, OHTA Chikara, TAKAKI Yumi, ENAMI Naoko, KAMADA Tomio
    電子情報通信学会総合大会, Mar. 2019, Japanese, 電子情報通信学会, 新宿区, Domestic conference
    Oral presentation

  • 車車間通信における電波伝搬特性の深層学習に基づく情報中継車両選択に関する検討
    YAMAMOTO Yujin, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara
    電子情報通信学会総合大会, Mar. 2019, Japanese, 電子情報通信学会, 新宿区, Domestic conference
    Oral presentation

  • インフラストラクチャモードで動作するマルチWi-Fi インタフェースメッシュネットワークの最適設定法
    TAKAHASHI Tomoki, MAENO Taka, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara, TAMURA Naoyuki
    電子情報通信学会MoNA研究会, Mar. 2019, Japanese, 電子情報通信学会, 目黒区, Domestic conference
    Oral presentation

  • LDMサービスのためのWi-Fiマルチインタフェース無線メッシュネットワークの構築
    MAENO Taka, TAKAHASHI Tomoki, YAMANISHI Takahiro, TAKAKI Yumi, OHTA Chikara
    電子情報通信学会総合大会, Mar. 2019, Japanese, 電子情報通信学会, 新宿区, Domestic conference
    Oral presentation

  • Optimal Configuration Method for Multi Wi-Fi Interface Mesh Networks Operating in Infrastructure Mode
    Tomoki Takahashi, Taka Maeno, Yumi Takaki, Tomio Kamada, Chikara Ohta, Naoyuki Tamura
    IEICE Technical Report, MoNA, Feb. 2019, Japanese

  • Optimal Configuration based on Constraint Programming for Wireless Mesh Networks with Multi-Interface in IEEE802.11 Infrastructure Mode
    高橋 智輝, 前野 誉, 高木 由美, 鎌田 十三郎, 太田 能, 田村 直之
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Nov. 2018, Japanese, 電子情報通信学会

  • IEEE802.11インフラストラクチャモードマルチインタフェース無線メッシュネットワークのための制約プログラミングによる最適設定法
    TAKAHASHI Tomoki, MAENO Taka, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara, TAMURA Naoyuki
    電子情報通信学会CCS研究会, Nov. 2018, Japanese, 電子情報通信学会, 神戸市, Domestic conference
    Oral presentation

  • 消防活動での無人航空機の利活用に向けた現状と課題
    KASHIHARA Shigeru, YAMAMOTO Atsushi, MATSUZAKI Kenta, MIYAZAKI Yasunari, SEKI Tomoya, URAKAWA Gou, FUKUMOTO Masahiro, OHTA Chikara
    日本災害情報学会第20回学会大会, Oct. 2018, Japanese, 日本災害情報学会, 文京区, Domestic conference
    Oral presentation

  • マルチチャネル無線メッシュネットワークのための無線チャネル・インタフェースモード割当問題の定式化
    TAKAHASHI Tomoki, MAENO Taka, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara, TAMURA Naoyuki
    電子情報通信学会ソサイエティ大会, Sep. 2018, Japanese, 電子情報通信学会, 金沢市, Domestic conference
    Poster presentation

  • デバイス間通信におけるマルチWi-Fiインタフェースを用いた柔軟な接続手法の提案
    HASHIMOTO Naoya, TAKAKI Yumi, KASHIHARA Shigeru, OHTA Chikara
    電子情報通信学会ソサイエティ大会, Sep. 2018, Japanese, 電子情報通信学会, 金沢市, Domestic conference
    Oral presentation

  • IoTを活用した放牧牛のインタラクション分析に基づく飼養管理技術の開発
    NISHIDE Ryo, OHKAWA Takenao, OYAMA Kenji, OHTA Chikara, TAKAKI Yumi
    平成30年度 第68回関西畜産学会大会, Sep. 2018, Japanese, 関西畜産学会, Domestic conference
    Oral presentation

  • IEEE802.11インフラストラクチャモードマルチインタフェース無線メッシュネットワークの最適設定法に関する一検討
    TAKAHASHI Tomoki, MAENO Taka, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara, TAMURA Naoyuki
    電子情報通信学会MIKA研究会, Sep. 2018, Japanese, 電子情報通信学会, 伊東市, Domestic conference
    Poster presentation

  • LDM サービス向け無線メッシュネットワークの基礎評価
    MAENO Taka, FAJARDO Jovilyn, TAKAHASHI Tomoki, OSHIMA Hiroshi, YANO Nagisa, TAKAKI Yumi, OHTA Chikara
    DICOMO2018 シンポジウム, Jul. 2018, Japanese, 情報処理学会, あわら市, Domestic conference
    Oral presentation

  • LDMサービス向け無線メッシュネットワークの基礎評価
    前野 誉, Jovilyn Fajardo, 高橋 智輝, 大島 宙, 矢野 渚, 高木 由美, 太田 能
    マルチメディア，分散協調とモバイルシンポジウム2018論文集, Jun. 2018, Japanese

  • Invited Talk : Wi-Fi Mesh Network for LDM Service and Information Sharing Service
    木下 和彦, 太田 能, 前野 誉, ファハルド ジョビリン
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, May 2018, Japanese, 電子情報通信学会

  • 平時LDMサービスと災害時情報共有サービスを提供するWi-Fiメッシュネットワーク
    KINOSHITA Kazuhiko, OHTA Chikara, MAENO Taka, FAJARDO Jovilyn
    電子情報通信学会ASN研究会, May 2018, Japanese, 電子情報通信学会, 広島市, Domestic conference
    Oral presentation

  • エッジ環境向け分散 key-value ストアと明示的データ分散管理手法
    NAGATO Takehiro, YAMANISHI Takahiro, KAMADA Tomio, TAKAKI Yumi, OHTA Chikara
    cross-disciplinary workshop on computing Systems, Infrastructures, and programming (xSIG2018), May 2018, Japanese, 情報処理学会, 千代田区, Domestic conference
    Oral presentation

  • Proposal of Channel Assignment Scheme based on Coloring Problem for Wireless Multi-channel Mesh Networks considering Traffic Flow
    矢野 渚, 前野 誉, 高木 由美, 鎌田 十三郎, 太田 能
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Mar. 2018, Japanese, 電子情報通信学会

  • 無線マルチチャネルメッシュネットワークのためのフローを考慮した彩色問題解法に基づくチャネル割当方式の提案
    YANO Nagisa, MAENO Taka, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    電子情報通信学会ネットワークシステム研究会, Mar. 2018, Japanese, 電子情報通信学会, 宮崎市, Domestic conference
    Oral presentation

  • 無線マルチチャネルメッシュネットワークのためのフローを考慮した彩色問題解法に基づくチャネル割当方式に関する一検討
    YANO Nagisa, MAENO Taka, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    電子情報通信学会総合大会, Mar. 2018, Japanese, 電子情報通信学会, 足立区, Domestic conference
    Poster presentation

  • ウェブデータストア上で個人情報共有するためのロールベース細粒度アクセス制御フレームワーク
    YAMANISHI Takahiro, KAMADA Tomioi, TAKAKI Yumi, OHTA Chikara
    電子情報通信学会総合大会, Mar. 2018, Japanese, 電子情報通信学会, 足立区, Domestic conference
    Poster presentation

  • LDM サービス向け無線メッシュネットワークの構築に関する検討
    MAENO Taka, TAKAHASHI Tomoki, OSHIMA Hiroshi, YANO Nagisa, TAKAKI Yumi, OHTA Chikara
    電子情報通信学会総合大会, Mar. 2018, Japanese, 電子情報通信学会, 足立区, Domestic conference
    Oral presentation

  • Overlapping Communication and Computation in an Artificial Market Simulation Using a Distributed Collection Library
    藤島, 大輔, 鎌田, 十三郎, 長門, 広洋, 高木, 由美, 太田, 能
    情報処理学会論文誌プログラミング（PRO）, Feb. 2018, Japanese, 大規模並列環境において，オブジェクト指向プログラミングが望まれるアプリケーション領域が増加している．人工市場シミュレーションソフトウェアの開発基盤であるPlhamは並列分散処理向けオブジェクト指向言語X10で実装されており，市場やトレーダなどはオブジェクトとして表現されている．Plhamでは市場計算および通信処理とトレーダの計算を並行して行えるよう，長期/短期トレーダを導入しその通信と計算のオーバラップを実現している．本発表では，我々のグループが提供している分散集合ライブラリをPlhamの並列実行系の実装に適用し，あわせてライブラリの機能拡張を行うことにより記述性改善を図った．分散集合ライブラリは，分散集合データ構造の要素であるオブジェクトの分散配置状況を管理し，要素の再配置機能やキャッシュの配置・更新機能を提供する．また，マルチコア環境において非同期に実行されその終了を待つことができる並列処理機能も提供する．これらの機能を利用することにより，Plhamでの通信と計算のオーバラップを簡潔に記述することができる． In large-scale parallel environment, application fields that prefer object oriented programming have been increasing. A Platform for Large-scale and High-frequency Artificial Market (Plham) is written in X10 language, and markets and traders are represented by objects. In Plham, to execute computation for markets and communication concurrently with computation for traders, long/short-term traders are introduced and communication is overlapped with computation. In this presentation, we try to apply our distributed collection library to a parallel execution system of Plham and enhance its functions to improve productivity. Our distributed collection library manages the distribution of element objects. It provides features to relocate elements or allocate and update caches of elements. To enable data parallel operation using multi-core CPUs, the library offers an asynchronous method that invokes data parallel processing over local elements using a thread pool and returns a condition variable to wait its completion. The overlapping of communication and computation in Plham was briefly described using these features.

  • Flexible Connectivity with Multiple Wi-Fi Interfaces for D2D Communication
    橋本 尚弥, 樫原 茂, 高木 由美, 太田 能
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Jan. 2018, Japanese, 電子情報通信学会

  • デバイス間通信におけるマルチ Wi-Fi インタフェースを用いた柔軟な接続手法の提案
    HASHIMOTO Naoya, KASHIHARA Shigeru, TAKAKI Yumi, OHTA Chikara
    電子情報通信学会モバイルネットワークとアプリケーション研究会, Jan. 2018, Japanese, 電子情報通信学会, 京都市, Domestic conference
    Oral presentation

  • Wi-Fiを用いたLDMエッジサーバの災害時利用
    KINOSHITA Kazuhiko, OHTA Chikara, MAENO Taka, FAJARD Jovylin
    電子情報通信学会ネットワークシステム研究会, Oct. 2017, Japanese, 電子情報通信学会, 足立区, Domestic conference
    Poster presentation

  • 無線マルチホップネットワークにおける隠れ端末による干渉と捕捉効果を考慮したルーティングメトリックの提案
    MAESAKO Keisuke, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    電子情報通信学会ソサイエティ大会, Sep. 2017, Japanese, 電子情報通信学会, 世田谷区, Domestic conference
    Oral presentation

  • 明示的なデータ分散管理を記述可能なエッジ環境向け分散データベースプラットフォーム
    長門 広洋, 纐纈 雄士, KAMADA TOMIO, TAKAKI YUMI, OHTA CHIKARA
    第9回ICN研究会ワークショップ, Aug. 2017, Japanese, 電子情報通信学会情報指向ネットワーク技術特別研究専門委員会(ICN研究会), 小金井市, Domestic conference
    Oral presentation

  • 無線タグによる和牛の個体識別・トラッキングに関する取り組み
    OHTA Chikara, OHKAWA Takenao, OYAMA Kenji
    電子情報通信学会コミュニケーションクォリティ研究会研究会, Jul. 2017, Japanese, 電子情報通信学会, 神戸市, Domestic conference
    Invited oral presentation

  • 分散集合ライブラリを用いた人工市場シミュレーションにおける通信と計算のオーバラップ実現
    藤島 大輔, 鎌田 十三郎, 長門 広洋, 高木 由美, 太田 能
    情報処理学会第115回プログラミング研究会 (SWoPP2017), Jul. 2017, Japanese, 情報処理学会, 秋田, Domestic conference
    Oral presentation

  • A Study for Improvement of Throughput in High Dense Wireless LAN Access Networks
    河崎 鷹大, 高木 由美, 鎌田 十三郎, 太田 能
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Mar. 2017, Japanese, 電子情報通信学会

  • User Selection Algorithm Considering Time Degradation of CSI for MU-MIMO Systems
    河北 雄飛, 高木 由美, 鎌田 十三郎, 太田 能
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Mar. 2017, Japanese, 電子情報通信学会

  • 無線 LAN における多端末・AP 環境下での最低スループット改善に関する研究
    KAWASAKI Takahiro, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    電子情報通信学会ネットワークシステム研究会, Mar. 2017, Japanese, 電子情報通信学会, 中頭郡読谷村, Domestic conference
    Oral presentation

  • マルチユーザMIMOにおけるフィードバック情報の経時劣化を考慮したユーザ選択手法
    KAWAKITA Yuhi, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    電子情報通信学会ネットワークシステム研究会, Mar. 2017, Japanese, 電子情報通信学会, 中頭郡読谷村, Domestic conference
    Oral presentation

  • 車車間通信を利用した歩行者検出性能向上手法の検討
    KABAYASHI Ryosuke, ENAMI Naoko, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    電子情報通信学会パターン認識・メディア理解研究会, Feb. 2017, Japanese, 電子情報通信学会, 札幌市, Domestic conference
    Poster presentation

  • Max-min Fair Flow Allocation considering Link Interference in Wireless Mesh Networks
    矢野 渚, 高木 由美, 鎌田 十三郎, 太田 能
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Dec. 2016, Japanese, 電子情報通信学会

  • 無線メッシュネットワークにおけるリンク間干渉を考慮したMax-Min Fairフロー割当
    YANO Nagisa, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    電子情報通信学会情報ネットワーク研究会, Dec. 2016, Japanese, 電子情報通信学会, 広島市, Domestic conference
    Oral presentation

  • 高密度 IEEE802.11 WLAN 環境下における最低スループット改善に関する研究
    KAWASAKI Takahiro, TAKAKI Yumi, KAMADA Tomioi, OHTA Chikara
    電子情報通信学会コミュニケーションクォリティ研究会ワークショップ, Oct. 2016, Japanese, 電子情報通信学会, 長野市, Domestic conference
    Poster presentation

  • A-14-5 A Study on Penetration Strategy of On-board Unit Taking Account of the Large-sized Vehicle and the Obstacle Shadowing in V2V Communications
    Takaki Yumi, Minami Hiroaki, Ohta Chikara, Tamaki Hisashi
    電子情報通信学会基礎・境界ソサイエティ/NOLTAソサイエティ大会講演論文集, Mar. 2016, Japanese, 一般社団法人電子情報通信学会

  • BP-2-4 Demonstration Test of Content Distribution Platform with In-Network Guidance
    Yagyu Tomohiko, Yamamoto Miki, Toda Hideki, Ohta Chikara
    Proceedings of the IEICE General Conference, Mar. 2016, Japanese, The Institute of Electronics, Information and Communication Engineers

  • 車車間通信における大型車両の遮蔽を考慮した車載機普及方策の一検討
    TAKAKI Yumi, MINAMI Hiroaki, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会総合大会, Mar. 2016, Japanese, 電子情報通信学会, 福岡市, Domestic conference
    Oral presentation

  • 初動対応期における様々な移動体を用いた情報収集・伝達手法の検討
    KASHIHARA SHIGERU, TAKAI MINEO, URAKAWA GO, FUKUMOTO MASAHIRO, OHTA CHIKARA
    Japan Society for Disaster Information Studies, 17th Conference, Oct. 2015, Japanese, Kofu-shi, 本論文では、ドローンによる情報収集手法を概説し、課題を踏まえた上で、実用化への次のステップとして、初動対応期を対象とした様々な移動体を用いた情報収集・伝達手法について検討する。, Domestic conference
    Oral presentation

  • A Study on Inter-flow Network Coding with Passive ACK for Efficient and Reliable Bidirectional Communication : Optimal Waiting Time for Encoding and Timing Control for Passive ACK
    安藤 誠, 高木 由美, 太田 能
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Aug. 2015, Japanese, 電子情報通信学会

  • 高効率高信頼双方向通信のためのパッシブ ACK 付きインターフローネットワークコーディング方式の検討
    ANDO Makoto, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会モバイルネットワークとアプリケーション研究会, Aug. 2015, Japanese, 電子情報通信学会, 神戸市, Domestic conference
    Oral presentation

  • A Study on Control of Transmission Power andCarrier Sense Threshold to Enhance Throughput and Fairness in IEEE802.11 Wireless Networks
    ROSLAN Irda, KAWASAKI Takahiro, NISHIUE TOSHIKI, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE MoNA, Aug. 2015, Japanese, IEICE, Kobe, Domestic conference
    Oral presentation

  • Rate Adaptation with Dataset for V2I Communication
    SAHARA Takemi, KASHIHARA Shigeru, OHTA Chikara, TAKAI Mineo, KANEDA Shigeru, YAMAGUCHI Suguru
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, Mar. 2015, Japanese, 一般社団法人電子情報通信学会, Existing rate adaptation mechanisms (RAs) are basically targeted for selecting the best transmission rate at indoor environments. As a result, RA in mobile environments, such as in Vehicular to Infrastructure communication, is more challenging due to frequently changing of channel quality. In this paper, we evaluate existing RAs in mobile environments using a simulator, and disclose the RAs' problems. We also present Rate Adaptation with Dataset (RAD) for selecting the appropriate data rate in mobile environments. Finally, we show that RAD outperforms other existing RAs in FTP/CBR communication.

  • A Study on Management of ContentID/Cache Location based on Estimation of Content Popularity for In-network Guidance
    ONIZUKA Takaki, KATAOKA Naomi, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Mar. 2015, Japanese, The Institute of Electronics, Information and Communication Engineers, Circulation of large-size contents like high-definition video leads to increasing content server load and core network traffic. Content oriented network (CON), which is expected to realize efficient content distribution, is vigorously studied as a future Internet. A Mapping Server with Cache-location Resolution (MSCR) has been proposed, which provides functions to resolve content ID and not only content sever location but also prospective cache locations in order to effectively utilize in-network caches by guiding content requests to content cache locations. Its performance is, however, evaluated only under assumption that content popularity is time-invariant. In this paper, we verify the effectiveness of MSCR under more realistic assumption where content popularity is time-variant. VPCL (Variable Prospective Cache Location) is also proposed, which varies the number of stored cache locations for each content according to its estimated popularity, so that ineffective query guidance is reduced. Simulation results show that MSCR is effective even in the case of time-variant content popularity and VPCL reduces unexpected query guidance.

  • Rate Adaptation with Dataset for V21 Communication
    SAHARA Takemi, KASHIHARA Shigeru, OHTA Chikara, TAKAI Mineo, KANEDA Shigeru, YAMAGUCHI Suguru
    IEICE Technical Committee on Mobile Network and Applications, Mar. 2015, Japanese, IEICE Technical Committee on Mobile Network and Applications, Shibaura Institute Technology, Domestic conference
    Oral presentation

  • インネットワーク誘導のためのコンテンツ人気度推定に基づく ContentID/Cache Location 情報管理に関する研究
    ONIZUKA Takaki, KATAOKA Naomi, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会ネットワークシステム研究会, Mar. 2015, Japanese, 電子情報通信学会, 宜野湾市, Domestic conference
    Oral presentation

  • BK-2 Lectures on How to Write Papers
    Saba Takahiko, KASAHARA Shoji, Ohta Chikara
    電子情報通信学会総合大会講演論文集, Feb. 2015, Japanese, 一般社団法人電子情報通信学会

  • Rate Adaptation with Dataset for V21 Communication
    佐原 壮海, 樫原 茂, 太田 能, 高井 峰生, 金田 茂, 山口 英
    情報処理学会研究報告. UBI, [ユビキタスコンピューティングシステム], Feb. 2015, Japanese, Information Processing Society of Japan (IPSJ), Existing rate adaptation mechanisms (RAs) are basically targeted for selecting the best transmission rate at indoor environments. As a result, RA in mobile environments, such as in Vehicular to Infrastructure communication, is more challenging due to frequently changing of channel quality. In this paper, we evaluate existing RAs in mobile environments using a simulator, and disclose the RAs' problems. We also present Rate Adaptation with Dataset (RAD) for selecting the appropriate data rate in mobile environments. Finally, we show that RAD outperforms other existing RAs in FTP/CBR communication.

  • 20190808
    山本 幹, 戸出 英樹, 太田 能, 柳生 智彦
    Kenkyu Houkoku, 2015, Japanese, National Institute of Information and Communications Technology

  • Demo: Contents Sharing among Mobile Users in Breadcrumbs-enabled Cache Network
    YAGYU Tomohiko, YAMAMOTO Miki, TODE Hideki, OHTA Chikara, KUROSE James
    IEEE the 12th Consumer Communications and Networking Conference (CCNC2015), Jan. 2015, English, IEEE, Las Vegas, International conference
    Poster presentation

  • Performance Evaluation of Efficient Reliable Packet Transfer Protocol for Wireless Multihop Bidirectional Communication Environment
    ANDO Makoto
    IEICE technical report. MoNA, Mobile network and applications, Sep. 2014, Japanese, The Institute of Electronics, Information and Communication Engineers, Bidirectional traffic flow appears in multi-sink wireless sensor networks (WSN) depending on their topologies. The aim of this study is to achieve efficient and reliable packet transmissions in such environments. To do so, first, we employ inter-flow network coding (NC) to reduce the number of relayed packets so that data collection delay is reduced compared with an ordinary scheme which utilizes unicast communications with acknowledgement (ACK). The inter-flow NC scheme is, however, unreliable because encoded packets are broadcasted and no ACK is executed for them. Therefore, we improve its reliability by a combination of passive ACK scheme. We call the proposed scheme by inter-flow NC with PA (IFNCPA). Through simulations, we confirm that IFNCPA scheme achieves shorter data collection delay and higher data-collection ratio compared with NC scheme and the ordinary scheme.

  • 無線マルチホップ双方向通信環境のための高効率高信頼パケット伝送プロトコルの評価
    ANDO Makoto, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会モバイルネットワークとアプリケーション研究会, Sep. 2014, Japanese, 電子情報通信学会, 石巻市, Domestic conference
    Oral presentation

  • Performance Evaluation of V2V Emergency Vehicle Warning System in Urban Area
    MINAMI Hiroaki, KINOSHITA Atsushi, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report. ASN, Ambient intelligence and sensor networks, Jul. 2014, Japanese, The Institute of Electronics, Information and Communication Engineers, An emergency vehicle such as an ambulance and a police-car needs to travel to a destination as quickly as possible. As a field of ITS (Intelligent Transport Systems), there is a lot of research on systems to support drive of emergency vehicles. Performance of such systems, however, has not been evaluated enough especially in urban environment. In this paper, we focus on the situation that an ambulance goes to a hospital via a traffic accident site in urban, and in this situation, we evaluate the effectiveness of emergency vehicle drive support based on vehicle-to-vehicle communications. We consider two types of schemes: in one scheme, an emergency vehicle broadcasts information on its location and velocity to prompt neighboring vehicles to avoid slowing down, changing lane, and entering intersection; in another scheme, an emergency vehicle floods information on its path to drive to prompt other vehicles to avoid using the path. Through simulation results, we confirm that the latter scheme shortens traveling time of an ambulance by 10.4% compared with the case of no support.

  • 都市部における車車間通信を用いた緊急車両通行支援システムに関する評価
    MINAMI Hiroaki, KINOSHITA Atsushi, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会知的環境とセンサネットワーク研究会, Jul. 2014, Japanese, 電子情報通信学会, 京都市, Domestic conference
    Oral presentation

  • A study on cache suppression control according to content popularity for in-network guidance
    KAWABATA Hiroki, ONIZUKA Takaki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report. Information networks, Nov. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers, In recent years, the popularity of large contents such as high-definition video and music is increasing content server loads and the amount of traffic on backbone networks. When a user obtains a content, he/she needs to resolve the content name (ID) as well as content server location. To mitigate the above problem, we have already proposed, a Mapping Server with Cache-location Resolution (MSCR), which resolves prospective cache locations (PCLs) close to the requesting user, and comfirmed the efficiency by some simulations. In this paper, we introduce an improved version of MSCR, named MSCR with Cache Suppression (MSCR/CS) which suppresses excess cache duplication of high popularity contents in a netowrk in order to increase the variety of content caches that enable users to obtain a content within the network.

  • インネットワーク誘導のためのコンテンツ人気度に応じたキャッシュ抑制制御に関する一検討
    KAWABARA Hiroki, ONIDUKA Takaki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会情報ネットワーク研究会, Nov. 2013, Japanese, 電子情報通信学会, 熊本市, Domestic conference
    Oral presentation

  • A Study on Transmission Power Control for Improvement of Throughput in Wireless LAN Access Networks
    NISHIUE Toshiki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Oct. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers, Internet is being transformed to "Internet of Things" to accommodate many things. In this study, we focus on IEEE802.11 as wireless access networks for IoT. In recent years, IEEE802.11APs (Access Points) using a same channel are often deployed near to each other. Such situation leads to "exposed terminal problem," where a terminal misses an opportunity of successful transmission due to unnecessary carrier sense to transmission by another terminal which belongs to a different AP. In this paper, we verify the effectiveness of transmission power control for uplink in order to mitigate exposed terminal problem. We analyze a simple model, and further perform packet-level simulations in more practical scenarios. As results, we confirm that transmission power control enhances uplink throughput.

  • 無線LANアクセス網におけるスループット改善のための送信電力制御法に関する 一検討
    NISHIUE Toshiki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会ネットワークシステム研究会, Oct. 2013, Japanese, 電子情報通信学会, 札幌市, Domestic conference
    Oral presentation

  • Load-Adaptive Flooding Schemes on Ad Hoc Networks
    Kinoshita Atsushi, Takaki Yumi, Ohta Chikara, Tamaki Hisashi
    Proceedings of the Society Conference of IEICE, Sep. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers

  • 負荷適応型フラッディング方式に関する一考察
    KINOSHITA Atsushi, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2013年電子情報通信学会ソサエティ大会, Sep. 2013, Japanese, 電子情報通信学会, 福岡市, Domestic conference
    Oral presentation

  • Case Study on Commercial Network Simulator : Scenargie and QualNet
    Ohta Chikara, Takaki Yumi
    IEICE technical report, May 2013, Japanese, The Institute of Electronics, Information and Communication Engineers

  • 商用シミュレータ活用事例 －ScenargieとQualNetについて－
    OHTA Chikara, TAKAKI Yumi
    電子情報通信学会ネットワークシステム研究会, May 2013, Japanese, 電子情報通信学会, 葉山町, Domestic conference
    [Invited]
    Invited oral presentation

  • Proposal of Detour Multipath Routing Protocol in Wireless Sensor Networks for Data Gathering
    FUJITA Keisuke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Mar. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers, In battery-powered wireless sensor networks (WSNs), system lifetime is strongly affected by drain of nodes' batteries. In severe environments such as disaster scenarios, WSNs also need to be tolerant to failure or loss of nodes due to external factors. The aim of this paper is to increase data collection ratio by enhancing tolerance to nodes' failure or loss while keeping system lifetime as long as possible in data-gathering WSNs. In this paper, we propose not only a detour multipath data gathering protocol called "Side Trip (ST)" scheme to enhance regional node-failure tolerance but also an improved version of ST called "Side Trip Network Coding (STNC)" scheme which utilizes network coding to reduce redundant packets without affecting the system lifetime significantly. In datagathering WSNs, nodes further away from sink node tend to have less relayed packets. In ST scheme, then, a node establishes another detour path which partially traces on nodes same hop away from the sink in order to increase the tolerance to geographically-correlated node-failure. In STNC, redundant packets from different source nodes are network-coded into an encoded packet in order to reduce redundant packets. By comparison of ST, STNC, and SMRP which is an existing multipath protocol by means of a self-developed simulator, it is shown that STNC and ST enhance tolerance for node failure compared with SMRP without significant influence to system lifetime.

  • Performance Evaluation of V2V Information Dissemination Schemes by Network Simulations Considering Urban Area
    KINOSHITA Atsushi, CAO Ke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Mar. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers, Recently, there have been an increase in research into VANETs (Vehicular Ad-hoc NETworks)communications, and various flooding schemes have been proposed for information dissemination in VANETs. These flooding protocols, however, were often evaluated under unrealistic conditions such as small-scale, line-of-sight, and static mobility environment. In this study, we evaluate how the performance of some well-known flooding schemes are affected according to whether vehicles are mobile or static and whether buildings exist or not. Simulation results show that these factors strongly affect the performance of flooding schemes.

  • BI-5-6 In-network Guide for Caching Networks
    Yamamoto Miki, Tode Hideki, Ohta Chikara, Yagyu Tomohiko
    Proceedings of the IEICE General Conference, Mar. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers

  • B-6-133 A Study on Content/Location Mapping for ln-network Content Cache Considering Cache Suppression
    Hashimoto Kensuke, Kawabata Hiroki, Takaki Yumi, Ohta Chikara, Tamaki Hisashi
    Proceedings of the IEICE General Conference, Mar. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers

  • B-19-13 A Method for Estimating Capacitor Voltage in Two-Dimensional Communication System
    Teshima Kosuke, Matsuda Takashi, Zhang Bing, Ohta Chikara
    Proceedings of the IEICE General Conference, Mar. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers

  • 二次元通信システムにおけるセンサノードのキャパシタ電圧推定法の検討
    TESHIMA Kosuke, MATSUDA Takasha, ZHANG Bing, OHTA Chikara
    2012年電子情報通信学会総合大会, Mar. 2013, Japanese, 電子情報通信学会, 岐阜市, 二次元通信システムとは，面で構成されたシート状通信媒体を用いた通信と給電を同時に可能にする新しい通信システムである.シート上に設置されたセンサノードはシートに入力された電力を受けることで充電をおこなうが，定在波の影響によりセンサノードの設置位置によって受信電力に大きく差が出る．そこで我々は，複数の入力点を用意して最適な入力点を選択する効率的な給電方式を提案している．この方式の実現のためには，どの入力点からどれだけの長さで給電をおこなうと，どれだけセンサノードのキャパシタ電圧が上昇するかを知る必要がある．本研究では，具体的なセンサノードのインピーダンスや受信電力の値を知ることなく，センサノードのキャパシタ電圧の推移から一定時間給電後のセンサノードのキャパシタ電圧を推定する方法について検討する．, Domestic conference
    Oral presentation

  • 都市環境を想定したシミュ レーションによる車車間情報配信手法の性能評価
    KINOSHITA Atsushii, CAO Ke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Mar. 2013, Japanese, 電子情報通信学会, 中頭郡読谷村, Domestic conference
    Oral presentation

  • 情報収集型無線センサネットワークにおける耐故障性を考慮した迂回マルチパス型情報収集プロトコルの提案
    FUJITA Keisuke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Mar. 2013, Japanese, 電子情報通信学会, 中頭郡読谷村, Domestic conference
    Oral presentation

  • キャッシュネットワークにおけるインネットワーク誘導
    YAMAMOTO Miki, TODE Hideki, OHTA Chikara, YAGYU Tomohiko
    2012年電子情報通信学会総合大会, Mar. 2013, Japanese, 電子情報通信学会, 岐阜市, CS)の概要について報告する．, Domestic conference
    Oral presentation

  • インネットワークキャッシュのためのキャッシュ抑制を考慮したコンテンツ/ロケーションマッピング方式の一検討
    HASHIMOTO Kensuke, KAWABARA Hiroki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2012年電子情報通信学会総合大会, Mar. 2013, Japanese, 電子情報通信学会, 岐阜市, Domestic conference
    Oral presentation

  • An Efficient Flooding Scheme for V2V Communications Considering Intersections of Urban Area
    CAO Ke, KINOSHITA Atsushii, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Mar. 2013, Japanese, 電子情報通信学会, 中頭郡読谷村, Domestic conference
    Oral presentation

  • Development of a demonstration system for User and Resource Management Technologies towards Pareto-optimal Wired-wireless Networks
    YAMORI Kyoko, OHTA Chikara, HASEGAWA Go, SHINKUMA Ryoichi, OGUCHI Masato, MURASE Tutomu
    Technical report of IEICE. CQ, Jan. 2013, Japanese, The Institute of Electronics, Information and Communication Engineers, In New Generation Networks, it is necessary to utilize network resources efficiently while avoiding selfish/greedy usages that result in unbalanced and poor resource utilization. Further, it is necessary to develop some mechanisms that appropriately organize and control network resource in order to satisfy various user requirements for power-saving, throughput, link speed, connectivity, and mobility. In this paper, the concept of PONET (Pareto Optimal NETwork) and the demonstration system are introduced.

  • Improvement and Evaluation of Rate Adaptation based on Average Fade Region Duration Estimation for IEEE802.11
    MISHIMA Chie, ROSLAN Irda, INAMOTO Tsutomu, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Jan. 2013, English, The Institute of Electronics, Information and Communication Engineers, Most rate adaptation schemes for IEEE802.11 such as ARF and AMARF decide to increase the data rate when the count-based success threshold of sequential frames is successfully transmitted. Unfortunately, ARF and AMARF do not work well if the terminals are not greedy to send messages and if the message length is vanable. We have proposed an RA scheme, which we call MARFFE (Multi-rate Auto Rate Fallback with average Fade region duration Estimation), it uses time-based success thresholds instead of the count-based one. In this manuscnpt, we improve MARFFE to promptly adapt changing environment, and evaluate MARFEE, AMARF, and ARF to confirm the effectiveness of MARFFE

  • パレート最適ネットワーク実現のためのユーザ・資源管理アプリケーションデモシステムの開発
    OHTA Chikara, HASEGAWA Go, MURASE Tutomu, SARKAR Dilip, RAYCHAUDHURI Dipankar
    電子情報通信学会コミュニケーションクォリティ研究会, Jan. 2013, Japanese, 電子情報通信学会, 東京, 新世代ネットワークでは，多岐にわたるユーザ要求条件（例えば，省電力，通信の速度・接続性，多様なモビリティ）を満足するよう，ユーザ間での資源競合を解決しながら，網資源・サービスを適切に構成し，ユーザが利用しやすい形で提供する仕組みが必要になると考えられる．本稿では，このコンセプトとしてパレート最適なネットワーク制御について述べ，実証実験のために試作した実験システムの概要を紹介する．, Domestic conference
    Oral presentation

  • Improvement and evaluation of rate adaptation based on average fade region duration estimation for IEEE 802.11
    MISHIMA Chiei, Roslan Irda Binti, INAMOTO Tsutomu, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Jan. 2013, Japanese, 電子情報通信学会, 熊本市, Domestic conference
    Oral presentation

  • Performance Evaluation of Distributed User Association based on User Utility in Wireless Networks
    IWAMI Takahiro, INAMOTO Tsutomu, TAKAKI Yumi, YAMORI Kyoko, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Dec. 2012, Japanese, The Institute of Electronics, Information and Communication Engineers, In recent, public WLANs based on IEEE802.11 standard are widely deployed. In an environment that several APs (Access Points) are available, a UTE (User Terminal Equipment) needs to choose an AP to associate. In such a case, the UTE associates with the AP with the strongest RSSI (Received Signal Strength Indicator). This simple and conventional scheme, however, may make the UTE choose a heavily loaded AP even though there is any unloaded AP. Thus, it possibly leads to inefficient network utilization. Then, so far, more sophisticate schemes for AP association and/or user guidance have been proposed. To the best of our knowledge, however, these existing schemes do not take into account of individual difference among UTEs with respect to user utility, physical data rate, traffic characteristics such as traffic demand and packet length. In this paper, we propose a distributed user association control considering such diversity of UTEs. Through our numerical simulations, we confirm that our distributed control scheme can improve user utility.

  • 無線アクセス網におけるユーザ効用に基づく分散型ユーザ帰属制御の性能評価
    IWAMI Takahiro, INAMOTO Tsutomu, TAKAKI Yumi, YAMORI Kyoko, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Dec. 2012, Japanese, 電子情報通信学会, 松山市, Domestic conference
    Oral presentation

  • 集団的ルール設計に関する初等的調査
    INAMOTO Tsutomu, OHTA Chikara, TAMAKI Hisashi
    平成24年度電気関係学会関西連合大会, Dec. 2012, Japanese, 電気学会・電子情報通信学会・照明学会・映像情報メディア学会・電気設備学会 各関西支部, 吹田市, Domestic conference
    Oral presentation

  • Performance Evaluation of Content/Location Mapping for In-network Guidance
    KAWABATA Hiroki, HASHIMOTO Kensuke, INAMOTO Tsutomu, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Oct. 2012, Japanese, The Institute of Electronics, Information and Communication Engineers, In recent years, the popularity of large contents such as high-definition video and music is increasing content. server load and the amount of traffic on core networks. It is indispensable for users to resolve a content ID in advance to get the content. Then, a mapping server which resolves a content ID by keywords is necessary. We have already proposed a Mapping Server with Cache-location Resolution (MSCR), which resolves prospective cache locations (PCLs) close to a requesting user as well as content ID. In this paper, we show additional simulation results to verify the effectiveness of an MSCR.

  • 二次元通信システムにおける定在波を考慮した入力点選択型給電方式の検討
    TESHIMA Kosuke, MATSUDA Takasha, ZHANG Bing, INAMOTO Tsutomu, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会USN研究会, Oct. 2012, Japanese, 電子情報通信学会, 福岡市, Domestic conference
    Oral presentation

  • パレート最適ネットワーク実現のためのユーザ・資源管理アプリケーション
    OHTA Chikara, HASEGAWA Go, MURASE Tutomu, SARKAR Dilip, RAYCHAUDHURI Dipankar
    電子情報通信学会ネットワークシステム研究会, Oct. 2012, Japanese, 電子情報通信学会, 東京, 我々は，新世代ネットワークの一つのあり方として「パレート最適ネットワーク」を想定し，これを実現するためのネットワーク制御アーキテクチャコンセプトとしてC3E2（Cognition, Coordination, and Cooperation for Economically Efficient resource-usage）を提案している．ネットワーク利用が成熟すると共に，トラヒック特性の多様化，利用形態の多様化，ネットワーク形態の多様化に加えて，ユーザ効用および網効用の多様化がますます進むと考えられる．これに対して，個々のユーザによる利己的な網資源選択は資源利用の偏重を生み，網資源の効率利用を図ることはできない．そこで，新世代ネットワークでは，様々な特性の網資源を上手く組み合わせ，多岐にわたるユーザ要求条件（例えば，省電力，通信の速度・持続性，多様, Domestic conference
    Oral presentation

  • ネットワーク誘導を利用した新世代コンテンツ配信アプリケーション
    YAMAMOTO Miki, TODE Hideki, OHTA Chikara, YAGYU Tomohiko
    電子情報通信学会ネットワークシステム研究会, Oct. 2012, Japanese, 電子情報通信学会, 東京, ユーザがコンテンツを取得するには，まずコンテンツがどこにあるのかを発見するコンテンツ発見フェーズを経たうえで，さらにコンテンツをその存在箇所からユーザまで転送するコンテンツ転送フェーズを経る必要がある．本研究では，これらコンテンツ発見フェーズとコンテンツ転送フェーズの双方に対し，ユーザにとってはコンテンツがどこから得られるのかには関心がなく，どのように効率的にコンテンツを取得できるのかという観点が重要であるという考えに基づき，負荷分散やトラヒック分散の観点で効率的なコンテンツ発見と，ロバスト性と効率を実現するコンテンツ転送を実現する．これにより，新世代コンテンツ配信アプリケーションが具備すべきSpace decoupling（コンテンツ提供者とコンテンツ要求者間のロケーションオリエンテッドな強い関係を緩和し，誰からコンテンツを得るのか，どこからコンテ, Domestic conference
    Oral presentation

  • インネットワーク誘導のためのコンテンツ／ロケーションマッピング
    KAWABARA Hiroki, HASHIMOTO Kensuke, INAMOTO Tsutomu, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Oct. 2012, Japanese, 電子情報通信学会, 宇治市, Domestic conference
    Oral presentation

  • 無線アクセス網における ユーザ効用にもとづく分散型ユーザ帰属制御
    IWAMI Takahiro, INAMOTO Tsutomu, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2012年電子情報通信学会ソサエティ大会, Sep. 2012, Japanese, 電子情報通信学会, 富山市, Domestic conference
    Oral presentation

  • 動的計画法の GPGPU による実装例 －確定的／確率的マルコフ決定過程を対象として－
    INAMOTO Tsutomu, OHTA Chikara, TAMAKI Hisashi
    平成24年電気学会電子・情報・システム部門大会, Sep. 2012, Japanese, 電気学会, 弘前市, Domestic conference
    Oral presentation

  • 多端末環境下におけるIEEE802.11とLTEのスループット性能に関する一検討
    TAKAKI Yumi, KANEDA Shigeru, TANAKA Yoshizo, OHTA Chikara, TAKAI Mineo, OKADA Yoji
    電子情報通信学会MoMuC研究会, May 2012, Japanese, 電子情報通信学会, 那覇市, Domestic conference
    Oral presentation

  • B-6-107 Study on Multi-Source Any Pair Network Coding for Wireless Sensor Networks
    Fujita Keisuke, Takaki Yumi, Ohta Chikara, Tamaki Hisashi
    Proceedings of the IEICE General Conference, Mar. 2012, Japanese, The Institute of Electronics, Information and Communication Engineers

  • BT-4-5 Network Management and Control Technologies for Pareto Optimal Network
    Yamori Kyoko, Ohta Chikara, Shinkuma Ryoichi, Hasegawa Go, Murase Tutomu, Oguchi Masato
    Proceedings of the IEICE General Conference, Mar. 2012, Japanese, The Institute of Electronics, Information and Communication Engineers

  • A Study on Content/Location Mapping for In-network Guidance
    KAWABATA Hiroki, HASHIMOTO Kensuke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Mar. 2012, Japanese, The Institute of Electronics, Information and Communication Engineers, Breadcrumbs (BC) scheme has been proposed for content distribution in next-generation networks. In BC scheme, when a user obtains a content via networks, first, by using Mapping Server (MS), he/she needs to resolve a location of a server which stores the content and then issues a query toward the server. If the query encounters a corresponding BC on the way to the server, it is guided along the BC trail toward a cache which may store the content. If the query heads toward a prospective cache initially instead of the server, it is expected that the server load and traffic of core-networks can be reduced. In this paper, we study a MS to resolve cache-locations in addition to server-locations, which we call "MSCR: Mapping Server with Cache-location Resolution." Simulation results show that MSCR can suppress server-load and traffic of core-network compared with MS.

  • Performance Evaluation of Flooding Protocols in VANETs Considering Shadowing
    MURAKAMI Hiroaki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Mar. 2012, Japanese, The Institute of Electronics, Information and Communication Engineers, In recent years, with the fast development in ad-hoc wireless communications and vehicular technology, it is expected that VANETs (Vehicular Ad-Hoc Networks) will be realized. VANETs enable vehicles to easily collect and disseminate emergency information in short time. In urban areas, corner-lots at intersections are often occupied by buildings. In general, radio signal remarkably decreases when turning a corner from a LoS (line-of-sight) onto a NLoS (non-line-of-sight) street at an intersection. Therefore, emergency information is not disseminated efficiently into NLoS streets. In past studies on ITS, only small-scale simulations were executed and shadowing due to buildings were not taken into account. In this research, we try to run large-scale simulations of flooding protocols to disseminate emergency information, in which influence of shadowing is considered.

  • A Study on Estimation of Session-based Throughput in IEEE802.11 Wireless Access Network
    IWAMI Takahiro, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Mar. 2012, Japanese, The Institute of Electronics, Information and Communication Engineers, In recent years, public wireless local area networks (WLANs) access points (APs) using IEEE802.11 have been widely deployed. A wireless terminal may associate with an appropriate IEEE802.11 AP if it can predict throughput of up-link and down-link. In this study, we propose a simple method to estimate up-link and down-link throughput of IEEE802.11 AP service. By comparing results of simulations and those of the method, we have confirmed that the method can estimation the up-link and down-link throughput on session basis accurately.

  • 情報収集型無線センサネットワークのための任意組み合わせ型ネットワークコーディングに関する一検討
    FUJITA Keisuke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2012年電子情報通信学会総合大会, Mar. 2012, Japanese, 電子情報通信学会, 岡山市, Domestic conference
    Oral presentation

  • インネットワーク誘導のた めのコンテンツ/ロケーションマッピングに関する一検討
    KAWABATA Hiroki, HASHIMOTO Kensuke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Mar. 2012, Japanese, 電子情報通信学会, 宮崎市, Domestic conference
    Oral presentation

  • VANETsにおけるフラッディングプロト コルの建物によるシャドウイングを考慮した通信特性評価
    MURAKAMI Hiroaki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Mar. 2012, Japanese, 電子情報通信学会, 宮崎市, Domestic conference
    Oral presentation

  • IEEE802.11無線アクセスポイントにお けるセッションベーススループット推定に関する一検討
    IWAMI Takahiro, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会NS研究会, Mar. 2012, Japanese, 電子情報通信学会, 宮崎市, Domestic conference
    Oral presentation

  • Panel Discussion : Management and Control of User and Resource toward Pareto-optimal Wireless and Wired Networks
    Ohta Chikara, Hasegawa Go, Shinkuma Ryoichi, Yamori Kyoko, Oguchi Masato, Murase Tutomu, Sarkar Dilip, Raychaudhuri Dipankar
    IEICE technical report, Jan. 2012, Japanese, The Institute of Electronics, Information and Communication Engineers, We have proposed a network architecture concept named C3E2 (Cognition, Coordination and Cooperation for Economically Efficient resource-usage) for "Pareto-optimal networks" which we regard as a modality of future networks such as New Generation Networks. Advances of network usage will bring not only broad characteristics of traffic patterns, applications, and networks but also various user utilities and network utilities. In order to achieve Pareto optimality, it is necessary to utilize network resources efficiently while avoiding selfish/greedy usages that result in unbalanced and poor resource utilization. Further, it is necessary to develop some mechanisms that appropriately organize and control network resource in order to satisfy various user requirements for power-saving, throughput, link speed, connectivity, and mobility. In this literature, the C3E2 concept and some approaches of network control based on the concept are discussed.

  • Management and Control of User and Resource toward Pareto-optimal Wireless and Wired Networks
    OHTA Chikara, HASEGAWA Go, SHINKUMA Ryoichi, YAMORI Kyoko, OGUCHI Masato, MURASE Tutomu, SARKAR Dilip, RAYCHAUDHURI Dipankar
    電子情報通信学会技術研究報告. SR, ソフトウェア無線 : IEICE technical report, Jan. 2012, Japanese

  • BS-4-1 Distributed User Association Control based on User Utility in Wireless Access Networks
    Iwami Takahiro, Inamoto Tsutomu, Takaki Yumi, Ohta Chikara, Tamaki Hisashi
    Proceedings of the Society Conference of IEICE, 2012, Japanese, The Institute of Electronics, Information and Communication Engineers

  • 無線・有線統合環境におけるパレート最適NW最適ネットワーク実現のためのユーザおよび資源管理・制御機構
    OHTA Chikara, HASEGAWA Go, SHINKUMA Ryoichi, YAMORI Kyoko, OGUCHI Masato, MURASE Tutomu, SARKAR Dilip, RAYCHAUDHURI Dipankar
    電子情報通信学会ソフトウェア無線研究会, Jan. 2012, Japanese, 電子情報通信学会, 霧島市, Domestic conference
    Public symposium

  • Network Control for Pareto Optimality in Future Internet : User-Centric Wired-Wireless Cognitive Technology
    MURASE Tutomu, SHINKUMA Ryoichi, HASEGAWA Go, YAMORI Kyoko, OGUCHI Masato, OHTA Chikara, SARKAR Dilip, RAYCHAUDHURI Dipankar
    IEICE technical report, Sep. 2011, Japanese, The Institute of Electronics, Information and Communication Engineers, We have proposed a concept, C3E2 (Cognition, Coordination and Cooperation for Economically Efficient resource-usage) for Pareto optimality in future networks such as New Generation Networks. Advances of network usage could bring broad characteristics of traffic patterns, applications, networks as well as those of individual user utilities and network utilities. In order to achieve Pareto optimality, it is necessary to efficiently use network resources with avoiding selfish/greedy usages that result in unbalanced and poor resource utilization. Therefore, it is necessary to develop some mechanisms that appropriately organize and control network resource elements both to meet various user requirements such as power-saving, throughput, link speed and connectivity and to fit various kinds of mobility. The C3E2 concept and some approaches of network control based on the concept are here discussed.

  • Network Control for Pareto Optimality in Future Internet : User-Centric Wired-Wireless Cognitive Technology
    MURASE Tutomu, SHINKUMA Ryoichi, HASEGAWA Go, YAMORI Kyoko, OGUCHI Masato, OHTA Chikara, SARKAR Dilip, RAYCHAUDHURI Dipankar
    IEICE technical report, Sep. 2011, Japanese, The Institute of Electronics, Information and Communication Engineers, We have proposed a concept, C3E2 (Cognition, Coordination and Cooperation for Economically Efficient resource-usage) for Pareto optimality in future networks such as New Generation Networks. Advances of network usage could bring broad characteristics of traffic patterns, applications, networks as well as those of individual user utilities and network utilities. In order to achieve Pareto optimality, it is necessary to efficiently use network resources with avoiding selfish/greedy usages that result in unbalanced and poor resource utilization. Therefore, it is necessary to develop some mechanisms that appropriately organize and control network resource elements both to meet various user requirements such as power-saving, throughput, link speed and connectivity and to fit various kinds of mobility. The C3E2 concept and some approaches of network control based on the concept are here discussed.

  • パレート最適ネットワーク制御技術の実現にむけて ~ 無線・有線コグニティブ環境におけるユーザを主体としたネットワーク制御 ~
    MURASE Tutomu, SHINKUMA Ryoichi, HASEGAWA Go, YAMORI Kyoko, OGUCHI Masato, OHTA Chikara, SARKAR Dilip, RAYCHAUDHURI Dipankar
    電子情報通信学会コミュニケーションクオリティ研究会, Sep. 2011, Japanese, 電子情報通信学会, 熊本市, Domestic conference
    Invited oral presentation

  • Proposal of Rate Adaptation Scheme based on Average Fade Region Duration for IEEE 802.11
    MISHIMA Chie, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Jun. 2011, Japanese, The Institute of Electronics, Information and Communication Engineers, In IEEE802.11a/b/g/n, which are widely used as wireless LAN standards, multiple modulation rates are available. Then adaptive modulation schemes for IEEE802.11 wireless LAN has been studied in order to select an adequate modulation rate according to channel condition. ARF, which is known as a practical adaptive modulation scheme, has two drawbacks: 1) unnecessary and undesirable rate decrease due to frame collisions, and 2) low following capability to fluctuation of channel condition. In this paper, we propose a novel adaptive modulation scheme based on CARA, named CARA-FE, which estimates adequate timing for rate increase by learning average rate region duration. Simulation results show that CARA-FE achieves higher throughput than existing schemes, ARF, AMARF, and CARA.

  • Proposal and Evaluation of Broadcast Schemes Using RAD Control Based on Distance Information in Mobile Ad-Hoc Networks
    TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    The IEICE transactions on communications B, Jun. 2011, Japanese, The Institute of Electronics, Information and Communication Engineers, MANETにおけるブロードキャスト方式DISCOUNTに対し,RSSIに応じでRAD制御を行うDISCOUNT-SJ方式を提案する.シミュレーション実験により提案方式が配信率を維持し,転送率や配信時間を改善することを示す.

  • IEEE802.11 のための平均フェード範囲区間推定にもとづく適応変調方式の提案
    MISHIMA Chiei, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会RCS研究会, Jun. 2011, Japanese, 電子情報通信学会, 中頭郡, Domestic conference
    Oral presentation

  • Proposal and evaluation of flooding schemes using RAD control in maritime MANETs
    村上 浩章, 高木 由美, 太田 能
    IEICE technical report, May 2011, Japanese, 電子情報通信学会

  • 海上アドホックネットワークにおけるRAD制御を用いたフラッディング方式の提案と評価
    MURAKAMI Hiroaki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会AN研究会, May 2011, Japanese, 電子情報通信学会, 港区, Domestic conference
    Oral presentation

  • Acquiring Approval Voting Polysemous Rule Sets for Elevator Operation Problems by Genetics-Based Machine Learning
    INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    SICE Symposium on Systems and Information 2011, May 2011, Japanese, システム制御情報学会, 大阪, Domestic conference
    Oral presentation

  • マルチバンド無線アクセス網のための負荷バランスハンドオーバに関する一検討
    TANAKA Daiki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2011年電子情報通信学会総合大会, Mar. 2011, Japanese, 電子情報通信学会, 世田谷区, Domestic conference
    Oral presentation

  • マルチバンド無線アクセス網のためのモビリティ情報を考慮した負荷バランスハンドオーバに関する検討
    TANAKA Daiki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2011年電子情報通信学会NS/IN合同研究会, Mar. 2011, Japanese, 電子情報通信学会, 宜野湾市, Domestic conference
    Oral presentation

  • パレート最適ネットワーク制御技術の実現にむけて
    OHTA Chikara, 新熊 亮一, 長谷川 剛, 矢守 恭子, 村瀬勉
    2011年電子情報通信学会総合大会, Mar. 2011, Japanese, 電子情報通信学会, 世田谷区, Domestic conference
    Oral presentation

  • コンテンツキャッシュへのホップ数を考慮したインネットワーククエリ誘導方式の性能評価
    HASHIMOTO Kensuke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2011年電子情報通信学会総合大会, Mar. 2011, Japanese, 電子情報通信学会, 世田谷区, Domestic conference
    Oral presentation

  • B-6-36 Performance Evaluation of Hop-aware In-network Query Induction Scheme for Contents Cache
    Hashimoto Kensuke, Takaki Yumi, Ohta Chikara, Tamaki Hisashi
    Proceedings of the IEICE General Conference, Feb. 2011, Japanese, The Institute of Electronics, Information and Communication Engineers

  • BS-5-6 A Study on Load Balancing Handover for Multi-band Wireless Access Systems
    Tanaka Daiki, Takaki Yumi, Ohta Chikara, Tamaki Hisashi
    Proceedings of the IEICE General Conference, Feb. 2011, Japanese, The Institute of Electronics, Information and Communication Engineers

  • Study on Load Balancing Handover Considering Mobility Information for Multi-band Wireless Access Systems
    TANAKA Daiki, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    IEICE technical report, Feb. 2011, Japanese, The Institute of Electronics, Information and Communication Engineers, In recent years, terminals using multi-band wireless access systems are spreading because diverse wireless access systems are available. In this paper, we clarify the impact of terminal's mobility on channel capacity in an environment where a multi-band wireless system is available. Furthermore we investigate the effect of a load balancing handover based on channel capacity considering terminal's mobility. To doing so, we define a channel model, channel capacity model, channel allocation model, and user utility model. Our simulation results show that the capacity-based access point selection with load balancing handover considering terminal's mobility achieves higher user utility than the access point selection without load balancing handover.

  • 同一チャネルにより給電と通信をおこなう二次元通信センサシステムの充電特性
    TESHMA Kousuke, 松田 隆志, 張 兵, OHTA Chikara
    ユビキタスセンサネットワーク研究会, Jan. 2011, Japanese, 電子情報通信学会, 広島市, Domestic conference
    Oral presentation

  • コンテンツキャッシュへのホップ数を考慮したインネットワーククエリ誘導方式の提案
    HASHIMOTO Kensuke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2011年電子情報通信学会NS研究会, Jan. 2011, Japanese, 電子情報通信学会, 高松市, Domestic conference
    Oral presentation

  • Comparison of Interference Reduction Schemes by Femto Base Stations to Macro Cell Users
    TANABE Yuya, AFOLABI Akindele Segun, OHTA Chikara, TAMAKI Hisashi, TANAKA Yoshizo, YAMAMOTO Takashi, OKADA Yoji
    IEICE technical report, Dec. 2010, Japanese, The Institute of Electronics, Information and Communication Engineers, In 3GPP TR25.820, three kinds of approaches, access control, bandwidth control, and power control, to reduce interference from femtocell to macrocell are examined. Further, five types of configurations as combinations of these approaches are also discussed. The relative effectiveness among these configurations are, however, not clear since they are not compared in the same scenario enough. Therefore, at the beginning in this paper, under the simple scenario where one femto-cell exists in one macro-cell, we compare Shannon capacities of the following three configurations: 1) Open Access, Co-channel, and Fixed Power, 2) CSG (Closed Subscriber Group), Dedicated Channel, and Fixed Power, 3) CSG, Co-channel, and Adaptive Transmission Power. We also investigate conditions that transmission power control is effective.

  • マルチホップ無線ネットワークにおける受信SINRの均等化を目指した送信電力制御
    WATANABE Shunsuke, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2010年電子情報通信学会NS研究会, Dec. 2010, Japanese, 電子情報通信学会, 岡山市, Domestic conference
    Oral presentation

  • Macrocell batch resource allocation for a co-channel macrocell/femtocell network
    Akindele Segun Afolabi, OHTA Chikara, TAMAKI Hisashi
    IEICE Tech. Report, Dec. 2010, English, IEICE, 岡山市, Domestic conference
    Oral presentation

  • A Total Dominant Pruning-based Scheme with Passive ACK and Active NACK for Reliable Broadcasting in MANETs
    DION Yiyuan, TAKAKI Yumi, OHTA Chikara, TAMAKI Hisashi
    2010 IEICE Technical Committee on Network Systems, Dec. 2010, English, IEICE, 岡山市, Domestic conference
    Oral presentation

  • A Preliminary Study on Effects by Adopting Majority Rule to a Genetics-Based Machine Learning Method based on Polysemous Rules
    INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    SICE Symposium on Systems and Information 2010, Nov. 2010, Japanese, 計測自動制御学会, 京都, Domestic conference
    Oral presentation

  • A 58-uW Sensor Node LSI with Synchronous MAC Protocol
    S. Izumi, T. Takeuchi, T. Matsuda, H. Lee, T. Konishi, K. Tsuruda, Y. Sakai, C. Ohta, H. Kawaguchi, M. Yoshimoto
    Proceedings of Asia-aPacific Radio Science Conference (AP-RASC), Sep. 2010, English
    Others

  • A Preliminary Study on a Divide-and-Conquer Approach to Acquiring Polysemous Rule Sets for Job-shop Scheduling Problems
    INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    54th Annual Conference of The Institute of Systems, Control and Information Engineers, May 2010, Japanese, システム制御情報学会, 京都, Domestic conference
    Oral presentation

  • "時刻同期型MACプロトコルを用いる6.4μWシングルチップセンサーノードLSI,
    和泉 慎太郎, 李 赫鍾, 小西 恵大, 岡 顕久, 松田 隆志, 竹内 隆, 太田 能, 川口 博, 吉本 雅彦
    LSIとシステムのワークショップ 2010, May 2010, Japanese, 北九州市, Domestic conference
    Poster presentation

  • B-5-110 Proposal of Distributed Resource Allocation Scheme for Wireless Networks
    AFOLABI Akindele Segun, OHTA Chikara, TAMAKI Hisashi
    Proceedings of the IEICE General Conference, Mar. 2010, English, The Institute of Electronics, Information and Communication Engineers

  • B-21-8 Proposal on Rate Control Algorithm to Mitigate Gray Zone Effect in Wireless Ad-hoc Networks
    PHAM Nhy Nguyen Tu, DIAO Yiyuan, KATO Yusuke, TAKAKI Yumi, OHTA Chikara
    Proceedings of the IEICE General Conference, Mar. 2010, English, The Institute of Electronics, Information and Communication Engineers

  • Zero-Forcing Beamformingを用いたマルチユーザMIMOにおけるフィードバック情報の信頼性を考慮したユーザ選択手法
    YAMABAYASHI Jun, OHTA Chicara, TAMAKI Hisashi, KANEKO Megumi, HAYASHI Kazunori
    電子情報通信学会技術研究報告, Mar. 2010, English, 電子情報通信学会, 宮崎市, Domestic conference
    Oral presentation

  • Proposal on Rate Control Algorithm to Mitigate Gray Zone Effect in Wireless Ad-hoc Networks
    PHAM Nguyen Tu Nhy, DION Yiyuan, KATO Yusuke, TAKAKI Yumi, OHTA Chikara
    2010 IEICE General Conference, Mar. 2010, English, IEICE, 仙台市, Domestic conference
    Oral presentation

  • Proposal of Distributed Resource Allocation Scheme for Wireless Networks
    AFOLABI Akindele Segun, OHTA Chikara, TAMAKI Hisashi
    電子情報通信学会2010年総合大会講演論文集, Mar. 2010, Japanese, IEICE, 仙台市, Domestic conference
    Oral presentation

  • User Selection Algorithm Considering Reliability of CSIT for MU-MIMO Systems Using Zero-Forcing Beamforming
    YAMABAYASHI Jun, OHTA Chikara, TAMAKI Hisashi, KANEKO Megumi, HAYASHI Kazunori
    IEICE technical report, Feb. 2010, Japanese, The Institute of Electronics, Information and Communication Engineers, This paper proposes a user selection algorithm for multi-user multiple input multiple output (MU-MIMO) system using Zero-Forcing Beamforming (ZFBF). A base station (BS) employs the channel response between antennas of the BS and those of mobile stations (MS) for adjusting transmission weights. The BS gets the channel response by, for example, receiving feedbacks from MSs. Because the channel response varies over time, it involves the error margin and cannot be reliable as time passes by. When responses of channels with the error margin are used for selecting users and adjusting transmission weights by the BS, qualities of channels reduce as orthogonality of channels is lost and the interference between users increases. When MSs frequently give feedbacks of the channel response to the BS, the overhead in the uplink control increases. In this paper we proposed a user selection algorithm which employs a metric representing reliability of the channel response for balancing the sum rate capacity with the feedback frequency. The simulation results display that the proposed algorithm achieves larger sum rate capacity with lower feedback frequency than a conventional algorithm.

  • Performance Evaluation of Network Protocols using QualNet : GUI Environment and Simulator Architecture
    TAKAKI Yumi, OHTA Chikara
    IEICE technical report, Dec. 2009, Japanese, The Institute of Electronics, Information and Communication Engineers, QualNet is a network simulator which is developed by Scalable Network Technologies, Inc. Due to its high speed process and scalability, the user population is growing up. In this lecture, we talk about the overview of QualNet GUI environment and the simulator architecture for those unfamiliar with QualNet and/or those being at a loss what to do in order to modify the existing protocol models and/or develop new protocol models and then evaluate their performance. With the GUI environment, we explain Scenario Designer, Animator, Analyzer, and Packet Tracer. With the simulator architecture, we represent Message API, Layer API, Initialize/Event Dispatcher/Finalize functions, and how to manage protocol state variables.

  • [チュートリアル招待講演]QualNetによるネットワークプロトコル性能評価 －神戸大における事例とデモを交えて－
    TAKAKI Yumi, OHTA Chikara
    2009年電子情報通信学会技術研究報告, Dec. 2009, Japanese, 電子情報通信学会, 松山市, Domestic conference
    Invited oral presentation

  • A Preliminary Application of a Knowledge Discovery Method based on Action-Less Rule Sets
    INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    52nd Japan Joint Automatic Control Conference, Nov. 2009, Japanese, 大阪, Domestic conference
    Oral presentation

  • 時刻同期型MACプロトコルを用いる58-uWワンチップセンサノードプロセッサ
    和泉 慎太郎, 竹内 隆, 松田 隆志, 李 赫鍾, 小西 恵大, 鶴田 嵩, 酒井 康晴, 川口 博, 太田 能, 吉本 雅彦
    電子情報通信学会技術研究報告, Oct. 2009, Japanese, 電子情報通信学会, Domestic conference
    Poster presentation

  • A 58-μW Single-Chip Sensor Node Processor Using Synchronous MAC Protocol
    IZUMI Shintaro, TAKEUCHI Takashi, MATSUDA Takashi, LEE Hyeokjong, KONISHI Toshihiro, TSURUDA Koh, SAKAI Yasuharu, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    IEICE technical report, Sep. 2009, Japanese, The Institute of Electronics, Information and Communication Engineers, In this paper, we propose a single-chip ultra low-power sensor node processor with a synchronous media access control (MAC). It is comprised of a transceiver, i8051 micro processor, and dedicated MAC processor. The test chip occupies 3x3mm^2 in a 180-nm CMOS process, including 1.38M transistors. The power is 58.0μW under a network environment.

  • An Approach Using Genetics-Based Machine Learning to Complementing Legacy Rules for the Elevator Operation
    INAMOTO Tsutomu, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    International Symposium on Scheduling 2009, Jul. 2009, English, 機械学会, スケジューリング学会, Nagoya, Domestic conference
    Oral presentation

  • Implementation and Experiment of Publish/Subscribe System on Wireless Mesh Networks
    KATO Yusuke, DION Yiyuan, PHAM Nguyen Tu Nhy, YAGURA Ken-ichiro, KITADA Takayuki, YAMAGUCHI Kazuhiro, TAKAKI Yumi, KUWANO Mitsuhiro, OHTA Chikara
    Proc. of the Second International Conference on Advances in Mesh Networks MESH 2009, Jun. 2009, English, IARIA, Athens, International conference
    Oral presentation

  • A Simple Approach on Mitigating the Gray Zone Effect to Improve Throughput in IEEE802.11 Based Ad-hoc Network
    PHAM Nguyen Tu Nhy, DION Yiyuan, KATO Yusuke, YAGURA Kenichiro, TAKAKI Yumi, OHTA Chikara
    Proc. of the Second International Conference on Advances in Mesh Networks MESH 2009, Jun. 2009, English, IARIA, Athens, International conference
    Oral presentation

  • 時間同期型MACプロトコルの垂直統合設計によるセンサノードVLSIの低消費電力化
    和泉 慎太郎, 松田 隆志, 竹内 隆, 川口 博, 太田 能, 吉本 雅彦
    LSIとシステムのワークショップ2009 ポスターセッション, May 2009, Japanese, 電子情報通信学会集積回路研究専門委員会, 北九州国際会議場, Domestic conference
    Poster presentation

  • A Study on An Acquisition Method for Action-Less Rule Sets by Its Application to Job-shop Scheduling Problems
    INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    53rd Annual Conference of The Institute of Systems, Control and Information Engineers, May 2009, Japanese, システム制御情報学会, 神戸(とりやめ), Domestic conference
    Oral presentation

  • B-21-22 Transmission Rate Setting for the Gray Zone Problem in IEEE802.11 based MANETs
    PHAM Nhy Nguyen Tu, DIAO Yiyuan, KATO Yusuke, YAGURA Kenichiro, TAKAKI Yumi, OHTA Chikara
    Proceedings of the IEICE General Conference, Mar. 2009, English, The Institute of Electronics, Information and Communication Engineers

  • BS-5-7 Experimental Report for Word-mouth Information Distribution Service on the Wireless Ad-hoc Network
    Tanaka Yusuke, Yagura Ken-ichiro, Kato Yusuke, Takaki Yumi, Ohta Chikara, Sugiura Hironori, Omae Takashi, Kitada Takayuki, Yamaguchi Kazuhiro, Kuwano Mitsuhiro
    Proceedings of the IEICE General Conference, Mar. 2009, Japanese, The Institute of Electronics, Information and Communication Engineers

  • BS-5-6 A Study of Visualization with Regional Characteristic at Word-mouth Information Distribution Service
    Sugiura Hironori, Yagura Ken-ichiro, Kato Yusuke, Takaki Yumi, Ohta Chikara, Tanaka Yusuke, Omae Takashi, Kitada Takayuki, Yamaguchi Kazuhiro, Kuwano Mitsuhiro
    Proceedings of the IEICE General Conference, Mar. 2009, Japanese, The Institute of Electronics, Information and Communication Engineers

  • 無線アドホックネットワークにおけるクチコミ情報流通サービスの実証実験
    TANAKA Yusuke, YAGURA Ken-ichiro, KATO Yusuke, TAKAKI Yumi, OHTA Chikara, SUGIURA Hironori, OMAE Takashi, KITADA Takayuki, YAMAGUCHI Kazuhiro, KUWANO Mituhiro
    2009年電子情報通信学会総合大会, Mar. 2009, Japanese, 電子情報通信学会, 松山市, Domestic conference
    Oral presentation

  • 並列化実装した動的計画法による最適なエレベータ運行ルールの計算
    稲元 勉, 松本 卓也, 太田 能, 玉置 久, 村尾 元
    情報処理学会第71回全国大会講演論文集, Mar. 2009, Japanese, 情報処理学会, 草津市, Domestic conference
    Oral presentation

  • 適応度評価が例題に基づく遺伝的機械学習手法のサンプリングによる効率化技法
    稲元 勉, 太田 能, 玉置 久, 村尾 元
    第36回知能システムシンポジウム資料, Mar. 2009, Japanese, 計測自動制御学会, 京都市, Domestic conference
    Oral presentation

  • A Sampling-based Technique to Improving Efficiency of a Genetics-Based Machine Learning Method with Fitness Evaluation based on Problem Instances
    INAMOTO Tsutomu, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    36th SICE Symposium on Intelligent Systems, Mar. 2009, Japanese, 計測自動制御学会, 京都, Domestic conference
    Oral presentation

  • 狭帯域海上アドホック通信のための分散型送信電力制御の提案と評価
    WATANABE Shunsuke, OKADA Kazuya, TAKAKI Yumi, OHTA Chikara, KIDO Akira, ARITAKE Nobuo
    2009年電子情報通信学会技術研究報告, Mar. 2009, Japanese, 電子情報通信学会, 沖縄県中頭郡, Domestic conference
    Oral presentation

  • クチコミ情報流通サービスにおける地域特性の可視化に関する一検討
    SUGIURA Hironori, YAGURA Ken-ichiro, KATO Yusuke, TAKAKI Yumi, OHTA Chikara, TANAKA Yusuke, OMAE Takashi, KITADA Takayuki, YAMAGUCHI Kazuhiro, KUWANO Mituhiro
    2009年電子情報通信学会総合大会, Mar. 2009, Japanese, 電子情報通信学会, 松山市, Domestic conference
    Oral presentation

  • Transmission Rate Setting for the Gray Zone Problem in IEEE802.11 based MANETs
    PHAM Nguyen Tu Nhy, DION Yiyuan, KATO Yusuke, YAGURA Ken-ichiro, TAKAKI Yumi, OHTA Chikara
    2009 IEICE General Conference, Mar. 2009, English, IEICE, 松山市, Domestic conference
    Oral presentation

  • Isochronous MAC Protocol for Low-Power Wireless Sensor Node VLSI
    IZUMI Shintaro, MATSUDA Takashi, TAKEUCHI Takashi, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    IEICE technical report, Feb. 2009, Japanese, The Institute of Electronics, Information and Communication Engineers, In this paper, we propose the isochronous media access control (I-MAC) processor by cross layer design. The I-MAC can be simplified because all nodes are synchronized and predict their operations. And then, the time synchronization system is implemented in physical layer. Hence, a simple processor for the I-MAC can be implemented as dedicated hardware. As well, the power management module (PMM) controls the power supplies of the components, based on the I-MAC state transition of I-MAC processor. The proposal processor achieves a power of 10.93uW. The chip area is 200x200um2 in a 180-nm CMOS process.

  • Proposal and Evaluation of Distributed Transmission Power Control for Narrowband Maritime Ad-hoc Networks
    WATANABE Shunsuke, OKADA Kazuya, TAKAKI Yumi, OHTA Chikara, KIDO Akira, ARITAKE Nobuo
    IEICE technical report, Feb. 2009, Japanese, The Institute of Electronics, Information and Communication Engineers, In this paper, the simulation results on AODV (Ad hoc On-Demand Distance Vector) with transmission power control in technical committee of Ministry of Internal Affairs and Communications, "Development of Technical Examination Services Concerning Frequency Crowding," are shown. The committee are working on realization of maritime ad-hoc networks, and considering AODV with transmission power control since AODV is suitable for narrowband networks due to small overhead. Transmission power control is expected to reuse spatial resource efficiently by controlling a radio transmission range. As a result, more amount of simultaneous communications can be achieved. Simulation results show 5.6% and 29% increase of throughput on a random nodes scenario and a group nodes scenario.

  • 3A2 AN APPROACH USING GENETICS-BASED MACHINE LEARNING TO COMPLEMENTING LEGACY RULES FOR THE ELEVATOR OPERATION :
    Inamoto Tsutomu, Ohta Chikara, Tamaki Hisashi, Murao Hajime
    Proceedings of International Symposium on Scheduling, 2009, English, 日本機械学会, In this paper, an approach using a Genetic-Based Machine Learning (GBML) method to acquire rule sets which complement legacy rules for the elevator operation is shown. A rule set is designed to be comprised of unit-rules, each of which encodes an elevator's augmented attribute vector and matches an arbitrary elevator which has such attributes. The GBML method is built in the Pittsburgh-style and tailored for acquiring such rules sets. In computer illustrations, the effectiveness of acquired rule sets is displayed as for three traffic patterns.

  • High Performance Simulation Technology and Evaluation Scenario Management Framework:—QualNet and Scenargie—
    Takaki Yumi, Ohta Chikara, Kaneda Shigeru, Takai Mineo
    IEICE Communications Society Magazine, 2009, Japanese, The Institute of Electronics, Information and Communication Engineers, 本稿では，商用シミュレータQualNetとScenargieの解説を行っている．両シミュレータとも基本設計から並列処理による高速化を念頭に置いて設計されている点に特徴があり，忠実なモデルの実行やシミュレート可能なネットワーク規模の増大に寄与している．また後発のScenargieは，実世界の表現能力を向上させることや性能評価作業の効率を改善することを念頭に開発が進められている．QualNetについては，その開発の歴史として，並列処理ライブラリPARSECやQualNetの前身であるGloMoSimの並列処理高速化技術，商用シミュレータとしてのQualNetの特徴について解説している．Scenargieについては，そのねらいである実世界の表現能力の向上を実現するGIS（Geographical Information System）技術とマルチエージェントシミュレーション技術，シナリオ構築及び評価結果の集計・分析の効率化を実現するGUIによるシナリオ構築環境やデータベースとの連携技術について解説している．

  • A 58-μW Single-Chip Sensor Node Processor Using Synchronous MAC Protocol
    Izumi Shintaro, Yoshimoto Masahiko, Takeuchi Takashi, Matsuda Takashi, Lee Hyeokjong, Konishi Toshihiro, Tsuruda Koh, Sakai Yasuharu, Kawaguchi Hiroshi, Ohta Chikara
    ITE Technical Report, 2009, Japanese, The Institute of Image Information and Television Engineers, In this paper, we propose a single-chip ultra low-power sensor node processor with a synchronous media access control (MAC). It is comprised of a transceiver, i8051 micro processor, and dedicated MAC processor. The test chip occupies 3x3mm^2 in a 180-nm CMOS process, including 1.38M transistors. The power is 58.0μW under a network environment.

  • Computations of Optimal Elevator Operation Rules by a Parallel Implementation of a Dynamic Programming Method
    INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    情報処理学会第71回全国大会, Jan. 2009, Japanese, 情報処理学会, 滋賀, Domestic conference
    Oral presentation

  • A Simple Approach on Mitigating the Gray Zone Effect to Improve Throughput in IEEE802.11 based Ad-hoc Network
    PHAM Nguyen Tu Nhy, DION Yiyuan, KATO Yusuke, YAGURA Ken-ichiro, TAKAKI Yumi, OHTA Chikara
    2009 IEICE Technical Report, Jan. 2009, English, IEICE, 佐賀市, Domestic conference
    Oral presentation

  • Acquisition of Elevator Operation Rule-Bases Using Genetics-Based Machine Learning Considering Rule Independence
    INAMOTO Tsutomu, MATSUMOTO Takuya, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    進化計算シンポジウム2008, Dec. 2008, Japanese, 北海道, Domestic conference
    Oral presentation

  • Parallelizing Computation of Reachable Sets of Stochastic Discrete Event Systems Exhibiting Imbalanced State Transitions
    INAMOTO Tsutomu, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    SICE Symposium on Systems and Information 2008, Nov. 2008, Japanese, 計測自動制御学会, 兵庫, Domestic conference
    Oral presentation

  • A Parallel Computation of Reachable Sets of Elevator Systems by Distributing States by a Simple Method
    INAMOTO Tsutomu, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    平成20年度情報処理学会関西支部 支部大会, Oct. 2008, Japanese, 情報処理学会, 京都, Domestic conference
    Oral presentation

  • スケジュールの多重化によるリアクティブ・スケジューリングの静的最適化モデル
    杉川 智, 玉置 久, 諏訪 晴彦, 太田 能
    スケジューリング・シンポジウム2008講演論文集, Oct. 2008, Japanese, スケジューリング学会, 東京都, Domestic conference
    Oral presentation

  • B-6-36 Evaluation of routing protocol for marine ad hoc networks using narrowband digital wireless
    Okada Kazuya, Watanabe Shunsuke, Takaki Yumi, Ohta Chikara
    Proceedings of the Society Conference of IEICE, Sep. 2008, Japanese, The Institute of Electronics, Information and Communication Engineers

  • B-6-37 Mean Transmission Rate Estimation Scheme for the Channel Allocation in Multi-channel Access Networks
    Yamabayashi Jun, Higuchi Yuhi, Ohta Chikara, Tamaki Hisasi
    Proceedings of the Society Conference of IEICE, Sep. 2008, Japanese, The Institute of Electronics, Information and Communication Engineers

  • B-6-47 Proposition of Path Restructuring Procedure for Information Distribution Publish/Subscribe-type Word-mouth Information Distribution Service
    KATO Yusuke, Tu Nhy, Pham Nguyen, YAGURA Ken-ichiro, KITADA Takayuki, YAMAGUCHI Kazuhiro, TAKAKI Yumi, KUWANO Mitsuhiro, OHTA Chikara
    Proceedings of the Society Conference of IEICE, Sep. 2008, Japanese, The Institute of Electronics, Information and Communication Engineers

  • B-20-10 Study on Divided Static Random Access Memory Considering Data Aggregation for Wireless Sensor Nodes
    Sakai Yasuharu, Matsuda Takashi, Izumi Shintaro, Takeuchi Takashi, Fujiwara Hidehiro, Kawaguchi Hiroshi, Ohta Chikara, Yoshimoto Masahiko
    Proceedings of the Society Conference of IEICE, Sep. 2008, Japanese, The Institute of Electronics, Information and Communication Engineers

  • 狭帯域ディジタル無線を用いた海上アドホックネットワーク用ルーティングプロトコルの評価
    OKADA Kazuya, WATANABE Shunsuke, TAKAKI Yumi, OHTA Chikara
    2008年電子情報通信学会通信ソサイエティ大会, Sep. 2008, Japanese, 電子情報通信学会, 川崎市, Domestic conference
    Oral presentation

  • Publish/Subscribe 型クチコミ情報配信サービスのための情報配信木更新手法の提案
    KATO Yusuke, PHAM Nguyen Tu Nhy, YAGURA Ken-ichiro, KITADA Takayuki, YAMAGUCHI Kazuhiro, TAKAKI Yumi, KUWANO Mituhiro, OHTA Chikara
    2008年電子情報通信学会通信ソサイエティ大会, Sep. 2008, Japanese, 電子情報通信学会, 川崎市, Domestic conference
    Oral presentation

  • Decreasing Computational Cost of Dynamic Programmings for Binary Coded Models by Algebraically Localizing State Transition Functions
    INAMOTO Tsutomu, OHTA Chikara, TAMAKI Hisashi, MURAO Hajime
    2008 Electronics, Information and Systems Conference, Electronics, Information and Systems Society of Japan, Aug. 2008, Japanese, 電気学会, 北海道, Domestic conference
    Oral presentation

  • Implementation of Publish/Subscribe System on Wireless Mesh Networks-Word-mouth Information Distribution Service-
    YAGURA Ken-ichiro, KATO Yusuke, KITADA Takayuki, YAMAGUCHI Kazuhiro, TAKAKI Yumi, KUWANO Mitsuhiro, OHTA Chikara
    7th Asia-Pacific Symposium on Information and Telecommunication Technologies, Apr. 2008, English, IEICE, Bandos Island, International conference
    Oral presentation

  • B-6-6 Proposition of Path Establishment Protocol for Information Distribution Publish/Subscribe-type Word-mouth Information Distribution Service
    YAGURA Ken-ichiro, KATO Yusuke, KITADA Takayuki, YAMAGUCHI Kazuhiro, TAKAKI Yumi, KUWANO Mitsuhiro, OHTA Chikara
    Proceedings of the IEICE General Conference, Mar. 2008, Japanese, The Institute of Electronics, Information and Communication Engineers

  • B-6-7 Implementation of Word-mouth Information Distribution Service with Publisher/Subscribe Method on the Wireless Ad-hoc Network Infrastructure
    Kitada Takayuki, Yagura Ken-ichiro, Kato Yusuke, Takaki Yumi, Ohta Chikara, Nishimoto Daisuke, Matsui Ryota, Yamaguchi Kazuhiro, Kuwano Mitsuhiro
    Proceedings of the IEICE General Conference, Mar. 2008, Japanese, The Institute of Electronics, Information and Communication Engineers

  • Interaction analysis of higher education reform: a video-based-ethnography of practice-type-lessons for engineering
    Kashida Yoshio, Okada Mitsuhiro, Igarashi Motoko, Miyazaki Ayako, Deguchi Hirofumi, Manabe Rikutaro, Fujisaki Kazuhiko, Kitamura Takanori, Takayama Tomoko, Ohta Chikara, Tamaki Toshiaki, Terashima Yoshiyasu, Abe Chieko, Shimada Akihito, Koizumi Hideki
    Journal of university education research, Mar. 2008, Japanese, The University of Tokushima, ビデオエスノグラフィーは、当事者的知識を十分に摂取しながら行うビデオ分析であり、我々はこの方法で、高等教育改革の現場を研究した。生涯学習社会の到来を受けて、日本の高等教育は現在第2 次世界大戦直後以来の改革期にある。すなわち、「知識」より「生涯学習能力」の獲得を志向した、自発性を尊重するような様々な取り組みがなされ始めている。この高等教育の現場に対し、ワークプレース研究を行った。Ｂ大学工学部都市工学演習α班を分析対象とした調査の結果、①演習の課題解釈には「従来の指標の相対化の要求の程度」を巡って２つの解釈があり得たこと、②班内にはその２種類の解釈に対応した葛藤・対立的相互行為が存在したこと、③にもかかわらず、班内葛藤を生きる当事者がともに専門性（「都市工学」）を志向していたこと、④したがって、課題理解のいかんにかかわらず、班活動の全体が「都市工学演習」と呼び得るものになっていたこと、⑤その一方で、最終審査会場（ジュリー）ではこの２重性が十分レリバントなものとして浮かび上がって来ていなかったこと、これらのことがわかった。諸結果を総合すると、学生の自主的活動を尊重するタイプの、新しい学習方法の吟味・評価のためには、学生によるその方法の実践状況の分析が有意義であるだろうこと、また、それは、場合によっては教員の評価のパラダイムを変える力を持つだろうことなどが予測された。なお、本報告は、文科省科学研究費補助金「高等教育改革のコミュニケーション分析－現場における文化変容の質的検討－」（基盤研究（Ｂ）、 課題番号 １８３３０１０５、研究代表者：樫田美雄）ほかによる研究成果の一部である。

  • Implementation of Word-mouth Information Distribution Service with Publisher/Subscribe Method on the Wireless Ad-hoc Network Infrastructure
    Kitada Takayuki, Yagura Ken-ichiro, Kato Yusuke, Takaki Yumi, Ohta Chikara, Nishimoto Daisuke, Matsui Ryota, Yamaguchi Kazuhiro, Kuwano Mituhiro
    Proc. IEICE General Conference, Mar. 2008, Japanese, 電子情報通信学会, Kita-Kyushu, Domestic conference
    Oral presentation

  • Information Distribution Publish/Subscribe-type Word-mouth Information Distribution Service
    YAGURA Ken-ichiro, KATO Yusuke, KITADA Takayuki, YAMAGUCHI Kazuhiro, TAKAKI Yumi, KUWANO Mituhiro, OHTA Chikara
    Proc. IEICE General Conference, Mar. 2008, Japanese, 電子情報通信学会, Kita-Kyushu, Domestic conference
    Oral presentation

  • 2-102 Programing Counseling Room: Improvement of the level of the basic skills of all students
    EGUCHI Koji, YASUMURA Yoshiaki, NAKAMURA Masahide, TAKIGUCHI Tetsuya, OHTA Chikara, LUO Zhiwei
    Proceedings of Annual Conference of Japanese Society for Engineering Education, 2008, Japanese, Japanese Society for Engineering Education

  • Acquisition of a Rule-set for Autonomous Course Driving of a RC-Car
    Horigami Shinji, Ohta Chikara, Tamaki Hisashi
    Proceedings of the Annual Conference of the Institute of Systems, Control and Information Engineers, 2008, Japanese, The Institute of Systems, Control and Information Engineers, 模型自動車のコース走行における速度調節・操舵決定方法を獲得することを目的とし，まず模型自動車の運動特性をモデル化し，車両シミュレータを作成する．続いて，車両の速度調節・操舵の決定方法をシミュレータに実装し，シミュレーションベースで実験を行う．その結果より速度調節・操舵の決定方式の有効性・可能性を検討する．

  • 長波帯標準電波を用いた低電力センサノードのための垂直統合設計
    OTAKE Yu, ICHIEN Masumi, TAKEUCHI Takashi, GION Akihiro, MIKAMI Shinji, FUJIWARA Hidehiro, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    第11回システムLSIワークショップ ポスタセッション, Nov. 2007, Japanese, 電子情報通信学会集積回路研究専門委員会(ICD), 北九州市, Domestic conference
    Poster presentation

  • A-21-26 Improvement of Counter-based Broadcasting for Wireless Sensor Networks using Timer Control
    IZUMI S., MATSUDA T., MIKAMI S., KAWAGUCHI H., OHTA C., YOSHIMOTO M.
    Proceedings of the IEICE General Conference, Mar. 2007, Japanese, The Institute of Electronics, Information and Communication Engineers

  • ワイヤレスセンサネットワークのためのタイマ制御によるカウンターベースブロードキャスティング方式の改良
    IZUMI Shintaro, MATSUDA Takashi, MIKAMI Shinji, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    2007年電子情報通信学会総合大会, Mar. 2007, Japanese, 電子情報通信学会, 名古屋, Domestic conference
    Oral presentation

  • ワイヤレスセンサーネットワーク応用キャリアセンス機能を持つ433MHz帯、356-uW電圧増幅器
    OTAKE Yu, MIKAMI Shinji, TAKEUCHI Takashi, ICHIEN Masumi, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    第10回システムLSIワークショップ ポスタセッション, Nov. 2006, Japanese, 電子情報通信学会集積回路研究専門委員会(ICD), 北九州, Domestic conference
    Poster presentation

  • ワイヤレスセンサーネットワークにおける送信電力制御による送信効率劣化が消費電力モデルに与えるネガティブインパクト
    MIKAMI Shinji, TAKEUCHI Takashi, OTAKE Yu, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    第10回システムLSIワークショップ ポスタセッション, Nov. 2006, Japanese, 電子情報通信学会集積回路研究専門委員会(ICD), 北九州, Domestic conference
    Poster presentation

  • Isochronous MAC using Low Frequency Radio Wave Time Synchronization for Wireless Sensor Networks
    ICHIEN Masumi, TAKEUCHI Takashi, MIKAMI Shinji, KAWAGUCHI Hiroshi, OHTA Chikara, YOSHIMOTO Masahiko
    IEICE technical report, Oct. 2006, English, The Institute of Electronics, Information and Communication Engineers, This paper proposes Isochronous-MAC (I-MAC), which utilizes low-frequency radio waves time synchronization for radio controlled clocks, for sensor networks. Using I-MAC, based on the Low Power Listening (LPL), all sensor nodes wake and listen channel periodically and synchronously. Since a sender can easily predict wakeup time of an intended receiver, it can shorten the length of preamble to make the receiver prepare for reception of the following data packet. In the paper, we use an analytical model to investigate the impact of the data transmission frequency, the number of neighboring nodes, the wakeup period, the clock drift, and the time-synchronization frequency on the power consumption for consideration of the power overhead to perform the time synchronization. Those results demonstrate that I-MAC allows determination of any arbitrary wakeup period without much difficulty, whereas LPL requires a much more careful setting of the wakeup period because its optimum wakeup period is sensitive to the frequency of data transmission as well as to the number of neighboring nodes. Therefore, I-MAC has a great potential to reduce the power consumption in most situations compared with LPL, in spite of the overhead to perform time synchronization.

  • BS-10-5 Long-lived network by considering production tolerance or sensor node
    Yoshino Hironori, Aonishi Takafumi, Ichien Masumi, Matsuda Takashi, Ohta Chikara, Kawaguchi Hiroshi, Yoshimoto Masahiko
    Proceedings of the IEICE General Conference, Mar. 2006, Japanese, The Institute of Electronics, Information and Communication Engineers

  • センサノードの製造バラツキを考慮したネットワーク可用時間改善の一検討
    YOSHINO Hironori, AONISHI Takafumi, ICHIEN Masumi, MATSUDA Takashi, OHTA Chikara, KAWAGUCHI Hiroshi, YOSHIMOTO Masahiko
    2006年電子情報通信学会総合大会;BS-10-5, Mar. 2006, Japanese, 電子情報通信学会, 東京都, Domestic conference
    Oral presentation

  • Long-lived network by considering production trelance of sensor node
    YOSHINO Hironori, AONISHI Takafumi, ICHIEN Masumi, MATSUDA Takashi, OHTA Chikara, KAWAGUCHI Hiroshi, YOSHIMOTO Masahiko
    電子情報通信学会総合大会, Mar. 2006, Japanese, Tokyo, Domestic conference
    Oral presentation

  • Evaluation of GIT Routing Considering Aggregation Ratio in Sensor Networks
    AONISHI Takafumi, YOSHINO Hironori, MIKAMI Shinji, OHTA Chikara, KAWAGUCHI Hiroshi, YOHIMOTO Masahiko
    電子情報通信学会技術研究報告, Oct. 2005, Japanese, 新潟, Domestic conference
    Oral presentation

  • B-5-148 Impact on impedance mismatch of output power control for wireless sensor nodes
    Mikami Shinji, Takeuchi Takashi, Ohta Chikara, Kawaguchi Hiroshi, Yoshimoto Masahiko
    Proceedings of the Society Conference of IEICE, Sep. 2005, Japanese, The Institute of Electronics, Information and Communication Engineers

  • Impact on impedance mismatch of output power control for wireless sensor nodes
    MIKAMI Shinji, TAKEUCHI Takashi, OHTA Chikara, KAWAGUCHI Hiroshi, YOSHIMOTO Masahiko
    電子情報通信学会ソサイエティ大会, Sep. 2005, Japanese, 北海道大学, Domestic conference
    Oral presentation

  • Congestion Control in the Network Router Introducing a Nonlinear Characteristics
    NISHIUCHI Yusuke, UETA Tetsushi, OHTA Chikara
    IEICE technical report. Nonlinear problems, Jan. 2005, Japanese, The Institute of Electronics, Information and Communication Engineers, The congestion state of the packet in a network will get worse if the state is left as it is. Active Queue Management (AQM) predicts a congestion and rejects packet in the network router. One of the most fundamental AQM is Random Early Detection (RED). RED predicts the buffer of router and rejects packets by probability. If RED parameters suitable for environment of a network is set up, throughput and fairness of a network are improved. However, since the environment of a network changes dynamically, a setup of a RED parameters is difficult. Packet-dropping probability is determined in a linear probability according to the state of a buffer. In this report, we show that RED improve in quality, if a nonlinear curve substitutes for a linear of probability. Practically, we built the network environment of simulesion where some machines communicated by one machine, and we experiment in TCP connection.

  • MANETにおけるP2Pファイル共有のための最適インデックスサーバ数
    OHTA Chikara, GE Zihui, GUO Yang, KUROSE Jim
    電子情報通信学会技術研究報告. CS, 通信方式, Dec. 2004, English, 一般社団法人電子情報通信学会, 本稿では,モバイルアドホックネットワーク(MANET)におけるピア・ツー・ピアファイル共有のための二つの基本的な情報検索方式を比較している.インデックスサーバを利用することで,インデックスサーバ内のファイルインデックスを高速に検索することが可能になるが,キャッシュの一貫性を保つためにオーバヘッドが生じる.本稿では,二つのインデックスサーバキャッシュ方式(CC(Consistent Caching),LC(Local Caching))とフラッディング方式の比較をおこなった.本稿では,インデックスサーバ方式により,検索のオーバヘッドがフラッディング方式に比べてどのくらい削減できるのかを明らかにするとともに,最適インデックスサーバ数が,ネットワークサイズ,キュエリレート,インデックス生成レートに従ってどのように変化するかを調査した.比較にあたっては,二つのキュエリ方式,HQ(History Query)とLQ(Latest Query)を対象とした.数値結果から,ネットワークサイズ,インデックス生成レート,キュエリレートに応じて,CCとLCを選択すべきであることがわかった. In this paper, we compare two basic approaches towards providing peer-to-peer file-sharing (or more generally, information search) in mobile ad-hoc networks (MANETs). The use of index servers presents the possibility of locating a file index quickly in an index server cache, but requires additional overhead to maintain cache consistency. We compare the performance of the flooding approach to two index-server caching approaches: consistent caching and local caching. We quantify the reduction in search overhead using the index-server scheme rather than flooding in MANETs, and study how the optimal number of index servers varies according to network size, query rate, arid index generation rate. We compare the flooding scheme and the consistent caching and local caching schemes, for. two types of queries: history queries and latest queries. Numerical results show how one can choose between the alternatives of consistent caching and local caching depending on network size, index generation rate and query rate.

  • モバイルアドホック網における位置情報交換レスキューシステム
    NIKOLOV Andrey, OHTA Chikara, UEHARA Kuniaki
    電子情報通信学会技術研究報告. RCS, 無線通信システム, Jul. 2003, English, 一般社団法人電子情報通信学会, 位置情報と関連付けられた被災状況情報は救助活動にとって有用である.われわれは,モバイルアドホックネットワーク技術,P2Pリソース共有技術,GPS技術を利用して,災害救助活動時に位置関連情報を共有するためのグループ通信システムを開発している.本システムでは,救助隊員は,P2Pリソース共有技術によって,位置情報と関連付けられたテキスト,音声,画像といったさまざまな情報を効率よく共有することができる.モバイルアドホックネットワークは,救助隊員の機動性を高め,救助活動の迅速な展開を強化する.本システムでは,被災者の救助信号から得られる参照情報を共有することにより,救助隊員が被災者の位置を推測することを可能にしている.本稿では,関連技術の検討,レスキューシステムが満たすべき条件の明確化,システム実装の設計コンセプトの概要説明,今後の課題について述べている. Information about the extent of disaster related with precise location is useful for rescue operation. Based on Mobile Ad-hoc Network (MANET), Peer-to-Peer (P2P), Global Positioning System (GPS) technologies, we develop a system for team communication to share location aware information during disaster rescue operations. In our system, rescue workers efficiently share various types of data such as text, voice, and image, which are related with location obtained from GPS, using P2P resource sharing technology. MANET enhances mobility of rescue workers and quick deployment of rescue activity. Our system enables rescue works to estimate the location ofa rescuee by sharing reference information which is obtained from his or her beacon. In this paper, we define the requirements a rescue system has to fulfill, review the achievements in the respective technology fields, outline the design concepts for the systems implementation, and discuss proposals R)r further improvement.

  • Rescue System Based on Location Aware Information Exchange in Mobile AdHoc Network
    NIKOLOV Andrey, OHTA Chikara, UEHARA Kuniaki
    電子情報通信学会情報ネットワーク研究会, 2003, English
    Others

  • Rescue System on Location Aware Information Exchange in Mobile AdHoc Network
    NIKOLOV Andrey, 坪田 繁, 渡辺 照正, 太田 能, 上原 邦昭
    計測自動制御学会 システムインテグレーション部門講演会 講演概要集, pp.284,3J4-4, 2003, English, 計測自動制御学会 システムインテグレーション部門, 東海大学代々木キャンパス, Domestic conference
    Oral presentation

  • Improvement of TCP Throughput for IEEE 802.11 DCF in Wireless Multi-hop Networks
    HARADA Takahiro, OHTA Chikara, MORII Masakatu
    The Transactions of the Institute of Electronics,Information and Communication Engineers B, Dec. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, IEEE802.11DCFは,規格化が進み,無線LAN製品の主流となっていること,隠れ端末問題への対策としてRTS/CTSを利用できることなどから,モバイルアドホック網の性能評価やそのルーチング方式を実装する際のメディアアクセス制御(MACと略記)としてよく用いられている.しかし近年,IEEE802.11DCFをマルチホップ環境で利用した場合,TCPスループット特性が不安定になることがXuらによって明らかになった.これは,NAV BlockingによりRTS/CTS交換が連続して失敗することによりリンク切断が発生したと誤検出されることや,RTS/CTS交換の失敗によりRTSを受信した隣接局の仮想キャリヤセンスが誤機能することでチャネル利用効率が低下することが原因である.そこで本論文では,dot11ShortRetryLimitを大きな値に設定することでリンク切断の誤検出を回避できることを示すとともに,仮想キャリヤセンスの誤機能の影響を小さくすることが可能なRTS/CTS+CRTS方式を提案した.シミュレーション結果から,dot11ShortRetryLimitを大きな値に設定することでリンク切断誤検出の発生が減少し,RTS/CTS+CRTS方式と組み合わせることでスループット特性が向上することが明らかになった.

  • Improvement on Power Consumption in MANET : Effect of Battery-aware Routing and Directional MAC
    SAIKI Haruhiko, OHTA Chikara, MORII Masakatu
    IEICE technical report, Nov. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, As described in RFC2501, nodes are possibly operated by battery in MANET. In this case, if transmission relay is concentrated for a certain node, the node consumes buttery unfairly. For this problem, C. -K. Toh et al. considered battery-aware routings. The simulation experiment by C. -K. Toh et al., however, did not take account of power consumption to receive packets. In this study, we investigated effectiveness of power-aware routing by more realistic simulation where we consider power consumption to receive packets. As results, we revealed that power-aware routing can not be very effective in combination with omni-antenna. Further, we clarified that battery-aware routing is effective in combination with directional MAC using directional-antenna.

  • Improvement on Power Consumption in MANET : Effect of Battery-aware Routing and Directional MAC
    SAIKI Haruhiko, OHTA Chikara, MORII Masakatu
    IPSJ SIG Notes, Nov. 2002, Japanese, Information Processing Society of Japan (IPSJ), As described in RFC2501, nodes are possibly operated by battery in MANET. In this case, if transmission relay is concentrated for a certain node, the node consumes buttery unfairly. For this problem, C. -K. Toh et al. considered battery-aware routings. The simulation experiment by C. -K. Toh et al., however, did not take account of power consumption to receive packets. In this study, we investigated effectiveness of power-aware routing by more realistic simulation where we consider power consumption to receive packets. As results, we revealed that power-aware routing can not be very effective in combination with omni-antenna. Further, we clarified that battery-aware routing is effective in combination with directional MAC using directional-antenna.

  • Improvement on Power Consumption in MANET Effect of Battery-aware Routing and Directional MAC
    SAIKI Haruhiko, OHTA Chikara, MORII Masakatu
    IEICE technical report. Information networks, Nov. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, As described in RFC2501, nodes are possibly operated by battery in MANET. In this case, if transmission relay is concentrated for a certain node, the node consumes buttery unfairly. For this problem, c. -K. Toh et al. considered battery-aware routings. The simulation experiment by c. -K. Toh et al., however, did not take account of power consumption to receive packets. In this study, we investigated effectiveness of power-aware routing by more realistic simulation where we consider power consumption to receive packets. As results, we revealed that power-aware routing can not be very effective in combination with omni-antenna. Further, we clarified that battery-aware routing is effective in combination with directional MAC using directional-antenna.

  • Improvement of Power Consumption in MANET : Effect of Battery-aware Routing and Directional MAC
    SAIKI Haruhiko, OHTA Chikara, MORII Masakatu
    Technical report of IEICE. Multimedia and virtual environment, Nov. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, As described in RFC2501, nodes are possibly operated by battery in MANET. In this case, if transmission relay is concentrated for a certain node, the node consumes buttery unfairly. For this problem, C. -K. Toh et al. considered battery-aware routings. The simulation experiment by C. -K. Toh et al., however, did not take account of power consumption to receive packets. In this study, we investigated effectiveness of power-aware routing by more realistic simulation where we consider power consumption to receive packets. As results, we revealed that power-aware routing can not be very effective in combination with omni-antenna. Further, we clarified that battery-aware routing is effective in combination with directional MAC using directional-antenna.

  • Employment of Communication System Supporting Welfare Volunteer for Local Community : Development and Expansion Enterprise of Information Communication System for Welfare Activity Support at Kainan-town, Tokushima
    MAITANI Takao, ARAO Gorou, NAKABAYASHI Kumiko, NODA Masuhiro, MAENO Yoko, KAGEISHI Masaki, OHTA Chikara, MOHRI Masami, MORII Masakatu, KASHIDA Yoshio
    IEICE technical report. Welfare Information technology, Oct. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, We have constructed a communication system supporting welfare volunteer for local community at Kainan-town, Tokushima, under a project of TAO (Telecommunications Advancement Organization of Japan). Our system consists of three sub-systems: 1) Staff arrangement system to collect volunteer's schedules and to call adequate volunteers in sequence in order to ask whether he or she can serve requests from clients, 2) Information registration system to register volunteer activity, 3) Information distribution system to distribute volunteer information in multicast fashion,. The system was operated in practice from May 2001. Through the operation, we have investigated the availability of the system. In this paper, we explain the outline of the project and the three sub-systems, and discuss the issue of the system based on the results of the experiment.

  • Employment of Communication System Supporting Welfare Volunteer for Local Community : Development and Expansion Enterprise of Information Communication System for Welfare Activity Support at Kainan-town, Tokushima
    MAITANI Takao, ARAO Gorou, NAKABAYASHI Kumiko, NODA Masuhiro, MAENO Yoko, KAGEISHI Masaki, OHTA Chikara, MOHRI Masami, MORII Masakatu, KASHIDA Yoshio
    IEICE technical report. Speech, Oct. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, We have constructed a communication system supporting welfare volunteer for local community at Kainan-town, Tokushima, under a project of TAO (Telecommunications Advancement Organization of Japan). Our system consists of three sub-systems: (1) Staff arrangement system to collect volunteer's schedules and to call adequate volunteers in sequence in order to ask whether he or she can serve requests from clients, (2) Information registration system to register volunteer activity,(3) Information distribution system to distribute volunteer information in multicast fashion. The system was operated in practice from May 2001. Through the operation, we have investigated the availability of the system. In this paper, we explain the outline of the project and the three sub-systems, and discuss the issue of the system based on the results of the experiment.

  • Improvement of IEEE 802.11 DCF for Wireless Multi-hop Networks
    HARADA Takahiro, OHTA Chikara, MORII Masakatu
    IEICE technical report. Communication systems, Jun. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, IEEE 802.11 DCF is often used as a MAC to evaluate or to implement MANET. However, S. Xu et al. reveal that TCP throughput becomes unstable in multi-hop environment using IEEE 802.11 DCF. In this paper, we will show that wrong detection of link failure is avoidable by setting the value of dot11ShortRetryLimit large, and propose RTS/CTS+CRTS which can reduce the side effect of virtual carrier sense mechanism. Simulation results show that setting the value of dot11ShortRetryLimit large reduces wrong detection of link failure and RTS/CTS+CRTS mechanism enhances throughput.

  • Improvement of IEEE 802.11 DCF for Wireless Multi-hop Networks
    HARADA Takahiro, OHTA Chikara, MORII Masakatu
    Technical report of IEICE. RCS, Jun. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, IEEE 802.11 DCF is often used as a MAC to evaluate or to implement MANET. However, S. Xu et al. reveal that TCP throughput becomes unstable in multi-hop environment using IEEE 802.11 DCF. In this paper, we will show that wrong detection of link failure is avoidable by setting the value of dot11ShortRetryLimit large, and propose RTS/CTS+CRTS which can reduce the side effect of virtual carrier sense mechanism. Simulation results show that setting the value of dot11ShortRetryLimit large reduces wrong detection of link failure and RTS/CTS+CRTS mechanism enhances throughput.

  • Accuracy Improvement of Lecturer Position Detection for Partial Distribution System of High Definition Images
    TAKANO Tomohide, TERADA Keisuke, YAGO Haruo, TOKURA Nobuyuki, YASUKAWA Hiroshi, SASAKI Jun, HAYASHI Toshihiro, HAYASHIDA Yukuo, OTSUKA Takeshi, OHTA Chikara, MORII Masakatu
    IEICE technical report. Education technology, Mar. 2002, Japanese, The Institute of Electronics, Information and Communication Engineers, For most distance learning or teaching system, someone have to operate camera and edit image data. We develop high definition image distribution system by split data transmission. Our system transmits sequence images taken by plural cameras to each client via high speed network. On this system each client operate PC and get view of whole and enraged selected area. Sending lecture position applied for decreasing of distribution data flow and sound placement. In this paper, we discuss about the accuracy improvement of lecturer position detection, the reduction method of transmit data amount and the arrangement of the sound placement.

  • Evaluation Experiment of High Resolution Partial Images Distribution System via High Speed Networks
    OTSUKA Takeshi, SONE Naoto, TAKANO Tomohide, TOKURA Nobuyuki, OHTA Chikara, MORII Masakatu
    IEICE technical report. Communication systems, Dec. 2001, Japanese, The Institute of Electronics, Information and Communication Engineers, A high-resolution partial image distribution system(HPIDS)is one of network-applications through high-speed networks. It can be utilized for tele-education systems. The HPIDS consists of an image capture sub-system and an image distribution sub-system. From multi-platform point of view, we have developed clients of image distribution sub-system using Java applet. From the previous work[2], [3], we newly implement the history function for users to take a look of recieved pictures in mainly the University of Tokushima. In addition to this, the functions of detection of a lecture's position and voice distribution are also implemented by Optwave Laboratory. In this paper, we explain the functions newly implemented and experimental results.

  • Minimal Channel Interference Routing for Distributed Wireless Packet Networks
    OHTA Chikara, KAIHOTSU Kazunori, MORII Masakatu
    IEICE technical report. Information networks, Jun. 2001, Japanese, The Institute of Electronics, Information and Communication Engineers, Distributed control wireless networks(DCWNs) which consist of wireless routers have merits of high expansibility, fault-tolerance and so on. In a DCWN, however, a frame transmission of a wireless router restricts the ones of other wireless routers within its transmission area. Thus it has a demerit of the decrease of effective interface capacity due to link interference. In this paper, we propose "minimal link interference routing", and show some simulation results to compare with minimum hop routing and APFS. From simulation results, it is found that our method has larger throughput than minimum hop routing and APFS.

  • TCP Vegasの公平性の改良と実装
    渡辺 照正, 太田 能, 森井 昌克
    電子情報通信学会技術研究報告, May 2001, Japanese, 電子情報通信学会

  • Construction of Communication System Supporting Welfare Volunteer for Local Community : Development and Expansion Enterprise of Information Communication System for Welfare Activity Support at Kainan-town, Tokushima
    OHTA Chikara, FUJITA Kouji, MAITANI Takao, WAKAKI Isamu, KUWAYAMA Isao, ARAO Gorou, NODA Masuhiro, MORII Masakatu
    Technical report of IEICE. OFC, May 2001, Japanese, The Institute of Electronics, Information and Communication Engineers, We have constructed a communication system supporting welfare volunteer for local community at Kainan-town, Tokushima, under a project of TAO (Telecommunications Advancement Organization of Japan). Our system consists of three sub-systems: 1) Staff arrangement system to collect volunteer's schedules and to call adequate volunteers in sequence in order to ask whether he or she can serve requests from clients, 2) Information registration system to register volunteer activity, 3) Information distribution system to distribute volunteer information in multicast fashion,. The system is operated in practice from May 2001. Through the operation, we will find the problems of the system. In this paper, we explain the outline of the project and the three sub-systems.

  • Design Method for Multi Channel Distributed Wireless Packet Networks
    HARADA Takahiro, OHTA Chikara, MORII Masakatu
    IEICE technical report. Communication systems, May 2001, Japanese, The Institute of Electronics, Information and Communication Engineers, Multi-channel distributed wireless packet networks utilize several channels and interconnect them via gateway routers which can use all channel. Compared with single channel ones, such a multi-channel network is expected to increase network capacity since the channel interference can be decreased in addition to the increase of channel capacity itself. However, it is necessary to place gateway routers adequately and to allocate an adequate channel to each non-gateway router. In this paper, we propose a design method for Multi-channel distributed wireless packet networks. Our method is based on a heuristic approach and twofolded: linear programming and genetic algorithm. As a future work, we will evaluate our proposal design method using simulations.

  • Fairness Improvement of TCP Vegas and Its Implementation
    WATANABE Terumasa, OHTA Chikara, MORII Masakatu
    IEICE technical report. Communication systems, May 2001, Japanese, The Institute of Electronics, Information and Communication Engineers, TCP Reno provides good fairness property, but its throughput performance is not so fine in tong-fat pipe networks. On the other hand, in such a networks, TCP Vegas provides good throughput performance, but its fairness property is not so fine. In this paper, we develop the window control method of TCP Vegas in order to improve its fairness property. We show some results of simulation and implementation experiment using JGN. From these results, our improvement accomplishes the fairness performance which is almost equal to TCP Reno and the throughput one which is almost equal to TCP Vegas.

  • Design Method for Multi Channel Distributed Wireless Packet Networks
    HARADA Takahiro, OHTA Chikara, MORII Masakatu
    Technical report of IEICE. OCS, May 2001, Japanese, The Institute of Electronics, Information and Communication Engineers, Multi-channel distributed wireless packet networks utilize several channels and interconnect them via gateway routers which can use all channel. Compared with single channel ones, such a multi-channel network is expected to increase network capacity since the channel interference can be decreased in addition to the increase of channel capacity itself. However, it is necessary to place gateway routers adequately and to allocate an adequate channel to each non-gateway router. In this paper, we propose a design method for Multi-channel distributed wireless packet networks. Our method is based on a heuristic approach and twofolded: linear programming and genetic algorithm. As a future work, we will evaluate our proposal design method using simulations.

  • Wireless Ad-Hoc Network Technologies
    OHTA Chikara
    ITE Technical Report, 2001, Japanese, The Institute of Image Information and Television Engineers, MANET(Mobile Ad-hoc NETworks)has been discussed in IETF MANET WG, MANET is assumed to be used in various situations, say a case where rescue networks are needed in disaster or a case when mobile terminals should be connected each other with ease in a conference. Recently, MANET is being realized as mobile terminals become into wide use and wireless technologies have been developed. Existing routing methods for IP networks, however, is not applicable to MANET straightforward due to mobility of terminals. In this presentation, I will explain the characteristics and its requirements of MANET, performance issues, typical routing protocols(DSDV, CGSR, AODV, DSR, TORA, ABR, ZRP), and problems.

  • Evaluation Experiment of High Resolution Partial Images Distribution System via High Speed Networks
    OTSUKA Takeshi, SONE Naoto, TAKANO Tomohide, TOKURA Nobuyuki, OHTA Chikara, MORII Masakatu
    ITE Technical Report, 2001, Japanese, The Institute of Image Information and Television Engineers, A high-resolution partial image distribution system(HPIDS)is one of network-applications through high-speed networks. It can be utilized for tele-education systems. The HPIDS consists of an image capture sub-system and an image distribution sub-system. From multi-platform point of view, we have developed clients of image distribution sub-system using Java applet. From the previous work[2], [3], we newly implement the history function for users to takea look of received pictures in mainly the University of Tokushima. In addition to this, the functions of detection of a lecture's position and voice distribution are also implemented by Optwave Laboratory. In this paper, we explain the functions newly implemented and experimental results.

  • Proposal of an Routing Algorithm for Distributed Wireless Networks
    KAIHOTSU Kazunori, OHTA Chikara, MORII Masakatu
    Proceedings of the Society Conference of IEICE, Sep. 2000, Japanese, The Institute of Electronics, Information and Communication Engineers

  • Construction of High Resolution Partial Images Distribution System on High Speed Networks
    KUSUBA Katsumi, TAKANO Tomohide, TOKURA Nobuyuki, OHTA Chikara, MORII Masakatu, SHIMADA Sadakuni
    Technical report of IEICE. OFC, May 2000, Japanese, The Institute of Electronics, Information and Communication Engineers, We develop a higy resolution partial image distribution system as an application for high-speed network such as Fast Ethernet, Gigabit Ethernet and ATM. This system consists of two subsystems : image capture sub-system and image distribution sub-system. Several digital cameras for home use are utilized in image capture sub-system so that it can be constructed in low price. Each digital camera sends the captured image only when any change is detected. This enables the effective utilization of network resouerce. Image distribution system is based on Web technologies. WWW browser acquires JAVA applet from WWW server, and composes high resolution image from part still picture. This applet enables WWW browser to display the part which a user selects. In this report, we explain the high resolution partial image distribution system in detail.

  • Cluster Design Method for Hierarchical Distributed Wireless Local Loop
    KAIHOTSU Kazunori, SHIRAKAWA Yoshinori, OHTA Chikara, MORII Masakatu
    Technical report of IEICE. OFC, May 2000, English, The Institute of Electronics, Information and Communication Engineers, The distributed wireless packet network using wireless router ISM band is one of the most promising solutions to construct the access network to Internet. In the previous study, we have proposed the hierarchical distributed wireless packet networks (HDWPN) to enhance the scalability. In this paper, we provide a design method for the cluster configuratuon of HDWPN. Our method is a heuristic approach using simulated annealing and linear programming. Simulation results show that our design method can find better cluster configuration than that divided geographicall equally by manual operation.

  • Configuration Study of High Resolution Partial Image Distribution System on High Speed Networks
    Kusuba Katsumi, Takano Tomohide, Tokura Nobuyuki, Ohta Chikara, Morii Masakatu
    Proceedings of the IEICE General Conference, 2000, Japanese, The Institute of Electronics, Information and Communication Engineers

  • (96)徳島大学工学部知能情報工学科における創成型科目への取り組み(第24セッション 創成教育(IV)):: ネットワークを用いた対戦型ゲームのグループによる作成
    小野 功, 太田 能, 泓田 正雄, 伊藤 拓也, 越智 洋司, 毛利 公美
    工学・工業教育研究講演会講演論文集, 2000, Japanese, 公益社団法人 日本工学教育協会

  • Moment Calculating Algorithm of Busy Period of Discrete-Time M/G/1 Type Queue
    Ohta Chikara, Shimada You, Morii Masakatu
    日本オペレーションズ・リサーチ学会秋季研究発表会アブストラクト集, Sep. 1999, English, The Operations Research Society of Japan

  • Proposal of a Layered Routing Algorithm for Destributed Wireless Networks and Its Performance
    KAIHOTSU Kazunori, SHIRAKAWA Yoshinori, OHTA Chikara, MORII Masakatu, MANO Hiroshi
    IEICE technical report. Communication systems, Jun. 1999, Japanese, The Institute of Electronics, Information and Communication Engineers, In this paper, we propose a layered source routing algorithm for distributed wireless networks, which is named GLRDWN (Grouped Layered Routing for Distributed Wireless Networks). In GLRDWN nodes exchange the quality of wireless link cach other, and create the routing information in the node layer and the gateway and the routing information in the group layer. Such the layered structure of GLRDWN suppresses the amount of traffic of the control packet, and it leads to the increase of throuhtput of user packet. Further we compare the layered structure with the non-layered one using simulation. Simulation results show the effectiveness of GLRDWN in the sense that the layered structure brings the scalability for the number of nodes.

  • Proposal of a Layered Routing Algorithm for Destributed Wireless Networks and Its Performance
    KAIHOTSU Kazunori, SHIRAKAWA Yoshinori, OHTA Chikara, MORII Masakatu, MANO Hiroshi
    Technical report of IEICE. RCS, Jun. 1999, Japanese, The Institute of Electronics, Information and Communication Engineers, In this paper, we propose a layered source routing algorithm for distributed wireless networks, which is named GLRDWN (Grouped Layered Routing for Distributed Wireless Networks). In GLRDWN nodes exchange the quality of wireless link cach other, and create the routing information in the node layer and the gateway and the routing information in the group layer. Such the layered structure of GLRDWN suppresses the amount of traffic of the control packet, and it leads to the increase of throuhtput of user packet. Further we compare the layered structure with the non-layered one using simulation. Simulation results show the effectiveness of GLRDWN in the sense that the layered structure brings the scalability for the number of nodes.

  • A Proposal of Moment Calculating Algorithm of Busy Period of Discrete-Time M/G/1 Type Queue and Its Applications
    SHIMADA You, YAMAMURA Takeshi, OHTA Chikara, MORII Masakatu
    IEICE technical report. Information networks, Jun. 1999, English, The Institute of Electronics, Information and Communication Engineers, In this paper, we propose the algorithm to calculate moments of busy period of the discrete-time M/G/1 type queue with finite buffer. Further, we show the application of our algorithm to the approximate analysis of HOL (Head Of Line) priority queue with two traffic-classes. As an example, we evaluated the accuracy of the approximate analysis considering the second moment of busy period in high priority queue. Numerical results show that the cell loss ratio of low priority queue is estimated accurately by the approximate analysis named the decomposition approach.

  • Construction of WLL using low power data transmission system and its experimental results
    Shirakawa Yoshinori, Ohta Chikara, Mano Hiroshi, Shiraishi Yoshiaki, Morii Masakatu, Yamashita Toru, Takahashi Tomio, Takeda Yoshiyuki
    Technical report of IEICE. OFC, May 1999, Japanese, The Institute of Electronics, Information and Communication Engineers, In this paper, we report the wireless local loop (WLL) which is experimentally constructed in Wajiki Town, Tokushima prefecture mainly by the ministry of posts and telecommunications, and its experimental results. The WLL is realized as a distributed wireless network using low power CDMA transceiver, and it has some good features from the point of view of institution, management and cost. From the experimental results, it is observed that the WLL networks show the almost equal throughput to INS and the communication applications such as IP-FAX, IP-Phone, TV-phone, mail, Web server and video server are available in practice.

  • Proposal of Feedback Picture Sequence Control for MPEG Video Transfer through ATM Networks
    OHTA Chikara, MORII Masakatsu
    Technical report of IEICE. SSE, Jul. 1998, English, The Institute of Electronics, Information and Communication Engineers, This paper proposes a novel feedback picture sequence control(FPSC) for real-time MPEG video transfer through ATM networks in order to provide better QOS and more effective usage of network resource. The FPSC utilizes the feedback mechanism of ABR service and the flexibility of MPEG video coding in order to resolve the collision of I-pictures at ATM switches. The FPSC requires only a very little modification of usage of RM cell in ABR service. The MPEG encoder for the FPSC can also be realized easily without much modification of the ordinary MPEG encoder. Simulation results show that the FPSC can improve QOS such as cell loss ratio and mean buffering delay in the cell buffer of ATM switch.

  • Study on Construction of Local IXP and Its Experimental Results
    Shirakawa Yoshinori, Shiraishi Yoshiaki, Ohta Chikara, Sone Naoto, Morii Masakatsu
    Technical report of IEICE. OFC, May 1998, Japanese, The Institute of Electronics, Information and Communication Engineers, In this paper, we discuss the structure of local HTTP-IXP server and its experimental results. Such local HTTP-IXP server aims to reduce HTTP traffic, which is major in Internet, by refining the network topology among local ISP's and sharing WWW contents in local area effectively by means of the layered cache structure. Experimental results show that local HTTP-IXP server can reduce HTTP traffic in backborn network and improve quality of service of ISP.

  • Initial Phase Assignment Algorithms for Periodic and Bursty Sources in ATM Networks
    ISHIZAKI Fumio, OHTA Chikara
    IEICE technical report. Information networks, Mar. 1998, English, The Institute of Electronics, Information and Communication Engineers, Our study aims to construct the framework to accommodate periodic and bursty sources into ATM networks effectively. For this purpose, we develop two algorithms which can find a good combination of the initial phases of periodic sources in a short time. We then consider a CAC scheme which controls phase combinations of the periodic sources and decides whether a new call is accepted or not by taking account of the controlled phase combinations. Our CAC scheme will be applicable to real-time MPEG video traffic which will be major traffic in ATM networks. Simulation results show that our algorithms can find a bette combination of initial phases than those chosen randomly in any our trials.

  • Initial Phase Assignment Algorithms for Periodic and Bursty Sources in ATM Networks
    ISHIZAKI Fumio, OHTA Chikara
    Technical report of IEICE. SSE, Mar. 1998, English, The Institute of Electronics, Information and Communication Engineers, Our study aims to construct the framework to accommodate periodic and bursty sources into ATM networks effectively. For this purpose, we develop two algorithms which can find a good combination of the initial phases of periodic sources in a short time. We then consider a CAC scheme which controls phase combinations of the periodic sources and decides whether a new call is accepted or not by taking account of the controlled phase combinations. Our CAC scheme will be applicable to real-time MPEG video traffic which will be major traffic in ATM networks. Simulation results show that our algorithms can find a better combination of initial phases than those chosen randomly in any our trials.

  • Proposal of feedback-control of picture sequence for MPEG video transfer via ATM networks
    KITAMURA Tatsuyoshi, OHTA Chikara, MORII Masakatsu
    Proceedings of the IEICE General Conference, Mar. 1998, Japanese, The Institute of Electronics, Information and Communication Engineers

  • A Study of 2-Hop Transmission scheme in Mesh-type Lightwave Network
    KUDOU Hikaru, OHTA Chikara, ONOZATO Yoshikuni
    Technical report of IEICE. SSE, Feb. 1996, Japanese, The Institute of Electronics, Information and Communication Engineers, In this paper we propose a 2-Hop transmission scheme in the logical network topolopgy of lightwave network of the RookNet for high speed communication. In the proposed scheme it is possible to reduce the number of receivers and internal buffer size by using TDMA technology and ultrashort optical pulse technology. It has been shown from analysis that the proposed scheme achieves the maximum throughput of 0.58 that is better than the one of the RookNet and good delay performance under middle and high traffic load comparing with that of the RookNet.

  • A study on multiplexing characteristics of MPEG video sources considering picture coding type in ATM networks
    SHINAGAWA Kazuhiro, OHTA Chikara, ONOZATO Yoshikuni
    Technical report of IEICE. SSE, Sep. 1995, English, The Institute of Electronics, Information and Communication Engineers, MPEG is the most promising coding compression technique for video transmission in ATM networks. In MPEG coding, there are three picture types. The data amount of each picture type is different, and data loss of each picture type affects the quality of video differently. In the paper, we analyzed the effect of multiplexing of MPEG video sources in an ATM switching node for the cell loss rate of each picture type of a certain source. Transient analysis was also shown to investigate the effect of I-P-B pattern for the cell loss rate of each picture type. In a case study, numerical results showed that the value of cell loss rate of I-picture is greater than the value of overall one by almost one figure.

  • A Study on Interference Between Traffic Classes That Implement Different Traffic Controls
    Adi Andreas P, SATOH Katsunori, OHTA Chikara, ONOZATO Yoshikuni, SHIMIZU Hideo, KIMURA Hiroshige
    Proceedings of the Society Conference of IEICE, Sep. 1995, Japanese, The Institute of Electronics, Information and Communication Engineers, 高速パケット交換網において、音声、画像、データなどの様々なトラヒックを収容する場合、各トラヒックが要求する通信品質を満足する必要がある。そこで、音声や画像など一定の通信容量を必要とするトラヒックに対しては、呼接続数の制限により輻輳を防止する輻輳予防型トラヒック制御を適用し、データなどの遅延に寛容なトラヒックに対しては、帯域を共有するという目的から、輻輳発生時に送出レートを制限するフィードバック型トラヒック制御を適用することが考えられている。クラス別にこれらの輻輳制御を実装するためには、交換機においてクラス毎にバッファを設け、クラス間でセル転送制御(優先権制御)を行なう方法が考えられる。各クラスヘの帯域割当は、このセル転送制御により決定されるが、異なる輻輳制御を実装するクラス間にセル転送制御が及ぼす影響についての検討はまだ十分なされていない。そこで本研究では、まず、セル転送制御方式がフィードバック型トラヒック制御に及ぼす影響という観点から検討を行う。

  • Study on bandwidth allocation method using dynamic bandwidth control in ATM Networks
    SHINAGAWA Kazuhiro, OHTA Chikara, ONOZATO Yoshikuni, SHIMIZU Hideo, KIMURA Hiroshige
    Proceedings of the Society Conference of IEICE, Sep. 1995, Japanese, The Institute of Electronics, Information and Communication Engineers, 近年、B-ISDN において多様なサービスを実現する方法が検討されている。本稿では、ATM の可変容量性を利用したサービスとして、マルチポイント-ポイント接続において、複数の送信端末から伝送されてくる情報のうち重要度が高いものに大きな帯域を動的に割当てることにより、受信端末の下りリンクの限られた帯域を有効に利用する方法を提案する。本手法は、遠隔監視制御システムや遠隔講義システムヘの適用が可能である。

  • A Study on feedback type rate control scheme with adaptive parameter
    OHTA Chikara, YAMAMOTO Miki, IKEDA Hiromasa
    Proceedings of the IEICE General Conference, Mar. 1995, Japanese, The Institute of Electronics, Information and Communication Engineers, ATM-LANにおけるABRクラスやVBR^+クラスの輻輳制御としてフィードバック型レート制御方式が検討されている.これらの方式では,交換機を経由するコネクション数の影響が考慮されていない.本稿では,交換機を経由する送信中のコネクションの増減を交換機のセルキュー長の変動から検出し,端末が送出速度を増加させる際の加算幅を適応的に変更することで,遅延とスループットの改善をはかる適応パラメータ方式を提案する.

■ Research Themes
  • Integrated development of quantum annealing optimization into edge computing platform
    太田 能, 鎌田 十三郎, 榎並 直子, Finnerty Patrick・Martin
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 01 Apr. 2022 - 31 Mar. 2026
    イジングモデルで定式化された組み合わせ最適化問題を求解可能な量子アニーリング型コンピュータを模擬したイジングマシンのユビキタス化に期待し、エッジコンピューティングアプリケーション最適化応用のための要素技術開発とテストベッド実装による有効性検証に取り組む。課題1：ソフトウェア開発を容易にするソフトウェアプラットフォームのイジングマシン・オンサイト利用拡張開発・実装、課題2：エッジアプリケーションである情報通知サービスなどのイジングマシン応用最適化技術開発、課題3：エッジアプリケーションである歩行者検出・照合技術のイジングマシン応用高速・高精度化技術開発に取り組み、テストベッドに統合実装、イジングマシン最適化の有効性を検証する。 本研究では、前述した目的を達成するために、本年度は上記３つの課題に関し、以下の内容に取り組んだ。 （課題1）EC アプリケーションとして高度交通システムを想定した情報伝搬事例をベンチマークとして作成した。加えて宣言的ルールに基づく情報伝達機構と継続的クエリとの統合をおこなった。これは、IM などの外部計算機構と EC データサービスの連携技術の在り方を検討する一方で、継続的クエリを用いたサイバー空間におけるオブジェクト関係管理が今後の EC アプリケーションにとっても重要と考えたためである。 （課題2）IM の計算サーバ実装、情報配信サービスなどの EC アプリケーションにおける組み合わせ最適化問題を整理、イジングモデル/QUBO 定式化の検討、求解可能規模・解の質・求解時間の評価を行い、IM による求解に向き不向きな問題を整理、加えて、EC 通信システム最適化に取り組んだ。 （課題3）サンプリングアルゴリズムの改良のため、本年度はUnityにより作成した歩行者の3Dモデルから歩行者画像を生成し、歩行者情報照合の学習データとしての有効性を評価、検証した。

  • Integrated development of quantum annealing optimization into an edge computing platform
    太田 能
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 01 Apr. 2022 - 31 Mar. 2026

  • Health Monitoring of Grazing Cattle by Time Series Analysis of Interactions
    大川 剛直, 太田 能, 大山 憲二
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), Kobe University, 05 Apr. 2021 - 31 Mar. 2026
    本研究では、放牧牛に装着した無線センサタグを利用して得られる精緻な牛間インタラクションの時系列変化を分析することで、個別の牛から計測される運動情報や生体情報だけでは実現が困難であった高感度なヘルスモニタリング（ストレス検知、発情検知、健康状態把握、疾病・負傷発見）手法の開発を目的としている。令和3年度の主要な研究実績は以下の通りである。 放牧牛同士のインタラクションを抽出するためには、牛の位置を的確に把握することが求められる。そこで、牛間相互通信による位置推定の実現に向けて、双方向通信機能を有するBLE送受信デバイスの仕様について検討・試作を進めるとともに、受信電波強度データをもとに個々の放牧牛の位置推定が可能な手法について提案した。この手法では、放牧場のような実環境においてデータ欠損が頻繁に発生することに留意し、ゾーン分けによって欠損影響の削減を試みている。 また、詳細なインタラクション情報を得るためには、それぞれの時刻において牛がどのような行動を行っているかを把握する必要があることに着目し、BLE送受信デバイスに内蔵した加速度センサから得られる時系列データをもとに、個々の牛の行動（歩行、採食、横臥、佇立など）を推定するための手法について、基礎的な検討を実施した。 さらに、実際の牛における異常状態を把握するため、定期的な血液検査を実施し、データ蓄積を行った。具体的には、ストレス関連ホルモンであるコルチゾールの血中値をもとにストレスの度合いを定量化するとともに、一般生化学検査を通して、各個体の健康状態に関するデータを継続的に収集した。

  • Research and development of wired/wireless cooperative communication technology to reduce the weight of in-vehicle harnesses
    Makoto OKUHARA, Nobuyuki KURIOKA, Satoru SHIMIZU, Makoto Shirai
    Ministry of Internal Affairs and Communications, Strategic Information and Communications R&D Promotion Programme, Advanced radio wave effective use type (social deployment promotion type), Kobe University, May 2021 - Mar. 2023, Principal investigator

  • Ohta Chikara
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, 01 Apr. 2018 - 31 Mar. 2022, Principal investigator
    Most car-to-pedestrian traffic accidents are caused by pedestrians jumping out. In this research, (Task 1) we have developed an application platform (information/communication cooperation platform) that enables developers to quickly write edge computing (EC) applications by defining hook functions; (Task 2) as an application, we have developed a pedestrian detection algorithm that makes it possible to recognize pedestrians in dead spots by sharing and re-identifying pedestrian images through vehicle-to-vehicle communication; (Task 3) we have investigated the communication capacity by network simulation. Finally, we have revealed the effectiveness of the information/communication cooperation platform and the pedestrian detection algorithm.
    Competitive research funding

  • Quantitative measurement and visualization of social networks among community-dwelling elderly people.
    Masumoto Kouhei
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, 10 Jul. 2015 - 31 Mar. 2018
    Many developed countries are faced with the rapid aging of their populations and as a result, they have encountered severe problems. Mutual support and cooperation in neighborhoods and communities are essential for solving these problems. However, effective intervention strategies aimed at increasing older adults’ social networks have not yet been established. The present study examined whether a university-led community intervention that provided communication opportunities could increase older Japanese adults’ neighborhood social networks. The present study found that participants of the intervention expanded their neighborhood social network, but non-participants did not. Additionally, we successfully measured face-to-face interactions by using wearable sensors, and identified conditions and changes in communication networks, and we developed a method of statistical testing to evaluate a program to promote communication among residents.

  • Ohta Chikara
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2015 - 31 Mar. 2018, Principal investigator
    In multi-hop wireless sensor networks based on carrier-sense multiple access, there is a problem that throughput is lowered in bidirectional communication due to packet collision and packet retransmission caused by a hidden terminal problem. In this research, in order to realize highly efficient and reliable packet transmission in a bidirectional communication environment, IFNC (Inter-flow Network Coding with Passive ACK), which combines IFNC (Inter-flow Network Coding) and Passive ACK), was developed. We examined the control parameter optimization of encoding latency and passive ACK collision avoidance mechanisms in order to improve the performance of IFNCPA. Computer simulations revealed that IFNCPA is effective from the viewpoint of collection ratio and end-to-end delay.
    Competitive research funding

  • OHKAWA TAKENAO
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research, Grant-in-Aid for Challenging Exploratory Research, Kobe University, 01 Apr. 2015 - 31 Mar. 2018
    In this study, we presented several new methods of detecting estrus and monitoring health condition of cows through extraction and analysis of interaction between cows by focusing on cows' sociality. In order to extract various types of information about interaction, we developed some methods of tracking a cow and classifying its behavior based on the data obtained from an active BLE (Bluetooth Low Energy) tag attached on the neck of each cow and bird's eye videos. In addition, we proposed a method of predicting condition of the cow by analyzing temporal change of interactions and/or communities of cows and confirmed experimentally that the proposed method obtained accurate results of estrus detection.
    Competitive research funding

  • TAKAKI YUMI
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2015 - 31 Mar. 2018
    Emergency vehicles are required to travel safely and smoothly in order to increase the life-saving rate and save more lives.Therefore, in this study, we first studied the information delivery method leading to shortening the traveling time of emergency vehicles from the viewpoint of the penetration rate of onboard devices.Then, we evaluated by simulation experiment that what kind of vehicle type would be more effective if it was spreaded.As a result, we found that it is desirable to spread large vehicles and small vehicles in a balanced manner.Next, we studied the method of delivering approach notification from emergency vehicles and confirmed the superiority of the method by simulation experiment.
    Competitive research funding

  • 増本 康平
    科学研究費補助金／基盤研究(B), Apr. 2015 - Mar. 2018
    Competitive research funding

  • OHTA Chikara
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2012 - 31 Mar. 2015, Principal investigator
    In this study, we apply network coding which can reduce the number of packet transfers for multi-path configuration or multi-sink configuration which can increase dependability in data gathering wireless sensor networks. More precisely, STNC (Side Trip with Network Coding) for multi-path configuration and IFNCPA (Inter-Flow Network Coding with Passive ACK) for multi-sink configuration are proposed and the effectiveness of the proposed scheme is verified through simulation experiments, which contributes the development of network coding technologies for sensor networks.
    Competitive research funding

  • 新世代ネットワークアプリケーションの研究開発 ～ネットワーク誘導を利用した新世代コンテンツ配信アプリケーション～
    太田 能
    独立行政法人情報通信研究機構, 高度通信・放送研究開発委託研究 新世代ネットワークを支えるネットワーク仮想化基盤技術の研究開発, 2014, Principal investigator
    Competitive research funding

  • TAKAKI YUMI, OHTA Chikara
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 2011 - 2013
    In recent years, dissemination of emergency information, such as accidents and disasters, has been studied as an application of vehicle-to-vehicle (V2V) communications. Therefore, in this study, we focus on the flooding scheme, in which each vehicle rebroadcasts only once whenever it received a new information, among information delivery schemes. In urban areas where there are many high-rise buildings and intersection, information is hard to reach to vehicles which are located on roads of non-line-of-sight (NLOS). To cope with this problem, we propose a flooding scheme which gives higher priority of rebroadcasting to vehicles on NLOS roads in order to achieve quick delivery by utilizing RSSI (Received Signal Strength Indicator) instead of digital maps which are required to update periodical. And simulation results show the superiority of the proposed scheme in terms of reception ratio and delivery time.
    Competitive research funding

  • 新世代ネットワークアプリケーションの研究開発 ～ネットワーク誘導を利用した新世代コンテンツ配信アプリケーション～
    太田 能
    独立行政法人情報通信研究機構, 高度通信・放送研究開発委託研究 新世代ネットワークを支えるネットワーク仮想化基盤技術の研究開発, 2013, Principal investigator
    Competitive research funding

  • 新世代ネットワークアプリケーションの研究開発 ～ネットワーク誘導を利用した新世代コンテンツ配信アプリケーション～
    太田 能
    独立行政法人情報通信研究機構, 高度通信・放送研究開発委託研究 新世代ネットワークを支えるネットワーク仮想化基盤技術の研究開発, 2012, Principal investigator
    Competitive research funding

  • パレート最適ネットワーク実現のためのユーザ・資源管理アプリケーション
    太田 能
    独立行政法人情報通信研究機構, 高度通信・放送研究開発委託研究 新世代ネットワークを支えるネットワーク仮想化基盤技術の研究開発, 2012, Principal investigator
    Competitive research funding

  • OHTA Chikara
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 2009 - 2011, Principal investigator
    Wireless sensor networks are expected to realize various monitoring systems such as disaster monitoring for river floodplain, forest fire and so on. Sensor networks need to collect sensed data reliably as long time as possible. In this study, we developed network protocols such as reliable broadcasting schemes, adaptive modulation schemes, and path construction schemes to realize reliable data gathering considering power consumption, and verified their effectiveness by means of network simulations and demonstration experiments.
    Competitive research funding

  • 新世代ネットワークアプリケーションの研究開発 ～ネットワーク誘導を利用した新世代コンテンツ配信アプリケーション～
    太田 能
    独立行政法人情報通信研究機構, 高度通信・放送研究開発委託研究 新世代ネットワークを支えるネットワーク仮想化基盤技術の研究開発, 2011, Principal investigator
    Competitive research funding

  • パレート最適ネットワーク実現のためのユーザ・資源管理アプリケーション
    太田 能
    独立行政法人情報通信研究機構, 高度通信・放送研究開発委託研究 新世代ネットワークを支えるネットワーク仮想化基盤技術の研究開発, 2011, Principal investigator
    Competitive research funding

  • TAKAKI Yumi, OHTA Chikara
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 2008 - 2010
    First of all, the feasibility of data transmission over multi-hop wireless communications in 27/40MHz wireless bands was verified in the at-sea experiment. In this environment, transmission speed is extremely low, that is, 1,200bps. Then we developed a new broadcast scheme called DISCOUNT-SJ (distance and counter-based scheme with short jitter) in order to surely and quickly disseminate messages from land-station to vessels (esp. fishing boats) in such a narrow band environment. We also developed a transmission power control called EqPC (equalized power control) scheme to enhance throughput of unicast communications. Our simulation results show that are superior to the existing ones.
    Competitive research funding

  • YOSHIMOTO Masahiko, TUKAMOTO Masahiko, ARIKI Yasuo, TAKIGUCHI Tetuya, KAWAGUCHI Hirosi
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), Kobe University, 2006 - 2009
    The design technology of ultra-low power VLSI processor to improve the perception recognition ability of the next generation wearable computer has been developed. A SIFT Descriptor Generation Engine which features a VLSI oriented Scale Invariant Feature Transform (SIFT) algorithm was realized and it provides high energy efficiency, 2.79mJ/frame, and processing capability for HDTV resolution video (1920x1080 pixels) at 30 frames per second (fps). Moreover, the development of VLSI architecture for the real-time continuous speech recognition was completed about 20000 vocabularies.
    Competitive research funding

  • communication analysis of university educational reform : on-the-spot examination
    KASHIDA Yoshio, TERASHIMA Yoshiyasu, TAMAKI Toshiaki, FUJISAKI Kazuhiko, DEGUCHI Hirofumi, MIYAZAKI Ayako, TAKAYAMA Tomoko, OOTA Chikara, MANABE Rikutarou, IGARASHI Motoko, KITAMURA Takanori, ABE Chieko, OKADA Mitsuhiro
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), The University of Tokushima, 2006 - 2008
    ビデオエスノグラフィーという新しい研究手法を開発しつつ、実際的な分析にも成果をあげた。即ち、大学生が専門技能を学ぶ実践の状況を相互行為の観点から明らかにした。例えば、医学部PBLチュートリアルにおいて、レントゲン写真をみる'専門的'方法としての「離して見る」という技法が、教師から学ばれ、学生集団のなかで模倣的に獲得されていく状況が確認できた。教育を結果から評価するのではなく、プロセスとして分析していくことへの展望が得られた。ISCAR第2回サンジエゴ大会等で報告を行った。

  • OHTA Chikara, YOSHIMOTO Masahiko, KAWAGUCHI Hiroshi
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 2006 - 2008, Principal investigator
    無線センサネットワークは、センシング機能を有する小型ノードを無線通信によりマルチホップ接続した無線センサネットワークであり、センサから得られる実世界情報を収集し、アクチュエータを介して実世界へ関与するための基盤システムとして期待されている。本研究では、無線センサネットワークのための低消費電力通信プロトコルの開発をおこない、プロトタイプにおいて消費電力を81%削減した。
    Competitive research funding

  • ユーザニーズに基づいた街中クチコミ情報流通システムに関する研究開発
    太田 能
    2007, Principal investigator
    Competitive research funding

  • モバイルアドホック網におけるピア・ツー・ピア情報共有技術に関する研究
    太田 能
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), Grant-in-Aid for Young Scientists (B), Kobe University, 2004 - 2005
    本研究では,ネットワーク分断予測をおこなうファイル複製配置方式の基礎検討とシミュレーション評価実験をおこなった。 平成16年度に検討したハイブリッド型検索メカニズムを想定して,まず,これに適した最適ファイル複製数分布に関する基礎検討をおこなった.経路制御には,IETF MANET WGで議論されているOLSRを想定し,OLSRのトポロジ情報から,各ノードへの接続度を算出し,ネットワーク分断を予測する手法を検討した. シミュレーションにはQualNet3.8を用いた.その結果,OLSRでは,経路が安定せず,接続度が絶えず変化することように観測されることが明らかになった.そこでまず,経路を安定させるための方法について検討した.シミュレーションデータを分析した結果,経路が不安定になる要因は,グレイゾーン問題に起因していることがわかった.そこで次に,OLSRの性能改善を図ることを試みた.不安点リンクの除去とリンク間干渉をメトリックにとりいれることで,経路情報が安定し,スループットが約10パーセント改善されることを明らかにした. また,ネットワークの分断は,接続度が小さいところから必ず発生するのではないため,他の箇所で切断が発生していても,そこでの接続度が最小接続度を下回るまでは,その状況を発見できず,ネットワーク切断を早期に予測することが難しいことが明らかになった. この問題に対しては,最小カットセットとなるリンクの容量を増大させることで,他のリンクを最小カットセットに含ませることが可能であり,これによってリンク接続度の変化を検出する方法が有効と考えられる.

  • 太田 能
    科学研究費補助金／若手研究(B), 2005, Principal investigator
    Competitive research funding

  • IPネットワークにおけるベストエフォート型エンド間遅延保証制御に関する研究
    太田 能
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), Grant-in-Aid for Young Scientists (B), The University of Tokushima, 2002 - 2002

  • Structure analysis for Reed-Solomon codes and fast decoding method
    MORII Masakatu, MOHRI Masami, IWATA Kenichi, OHTA Chikara
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), The University of Tokushima, 1998 - 2000
    In the following, we summarize the main results of our studies. 1. A new decoding method for shortended Reed-Solomon codes We proposed a decoding algorithm for shortended Reed-Solomon codes using some information which is shortended symbol positions. 2. Decoding of Reed-Solomon codes beyond the error-correction bound We proposed a decoding method of Reed-Solomon codes beyond the error-correction bound. Our method is based on the histgram decoding and remainder decoding. 3. On computing the local distance profile for cyclic codes We proposed a method for computing the local distance profile of cyclic codes. Using our method, we can obtain the upper bound for decoding error probability. It is tighter than the usual upper bound (union bound).

  • 高速パケット交換網を介した動画像通信のための確定的エンド間遅延保証に関する研究
    太田 能
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Encouragement of Young Scientists (A), Grant-in-Aid for Encouragement of Young Scientists (A), The University of Tokushima, 1998 - 1999
    本研究の目的は,高速パケット(セル)交換網を介したMPEG動画像通信において,エンド・ツー・エンド遅延時間を保証可能なトラヒック制御パラメータの設定方法を確立し,コネクション受付制御への応用を検討することである.本年度は,平成10年度に開発した呼受付制御と組み合わせる候補パス選択アルゴリズムを検討した. 候補パス選択アルゴリズムとしては,Q.Maらが検討しているShortest-widest pathアルゴリズム,Widest-shortest pathアルゴリズム,Shortest-distanceアルゴリズムを対象とした.Widest-shortest pathアルゴリズムは遅延を優先して選択し,Shortest-widest pathアルゴリズムは最大残余帯域が大きなパスを選択する方式である.また,Shortest-distanceアルゴリズムは,遅延の負荷分散をバランスさせながらパス選択をおこなう方式である. 本研究では,Q.Maらとことなり,送信局での遅延も考慮したアプリケーションレベルでの遅延・廃棄保証を試みている.このため,ホップ数(+伝搬遅延)が小さくなると,平成10年度に開発した上界式からセッションへの割当帯域,スイッチに割当バッファをより小さく設定できる.このため,呼損率では,Short-distanceアルゴリズム,Shortest-widestアルゴリズムが,Widest-shortestアルゴリズムに比べてもより小さくなり,候補パス選択アルゴリズムとして優れていることが明らかになった.

■ Industrial Property Rights
  • センサネットワークにおける無線トランシーバー用電圧増幅器
    YOSHIMOTO MASAHIKO, OHTA CHIKARA, KAWAGUCHI HIROSHI, 三上 真司
    特願2007-035223, 15 Feb. 2007, 大学長, 特許5019362, 22 Jun. 2012
    Patent right

  • センサネットワークシステム及びメディアアクセス制御方法
    YOSHIMOTO MASAHIKO, OHTA CHIKARA, KAWAGUCHI HIROSHI, 一圓 真澄
    特願2006-279761, 13 Oct. 2006, 大学長, 特許4919204, 10 Feb. 2012
    Patent right

  • データ送信スケジューリング方法およびそれを用いたセンサネットワークシステム
    YOSHIMOTO MASAHIKO, KAWAGUCHI HIROSHI, OHTA CHIKARA, 三上 真司
    特願2006-279760, 13 Oct. 2006, 大学長, 特許4863069, 18 Nov. 2011
    Patent right

  • 基地局、端末装置、情報源装置及び通信方法
    OHTA CHIKARA, 樋口 雄飛
    特願2006-043111, 20 Feb. 2006, 大学長, 特許4756592, 10 Jun. 2011
    Patent right

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