Papers - KAMADA Tomio
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Person ReIDentification for Detection of Pedestrians in Blind Spots through V2V Communications. Reviewed
Kou Asano, Naoko Enami, Tomio Kamada, Chikara Ohta
Proceedings of IEEE Intelligent Transportation Systems Conference (ITSC2019) 764 - 770 2019
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CARAVAN: A Framework for Comprehensive Simulations on Massive Parallel Machines Reviewed
Yohsuke Murase, Hiroyasu Matsushima, Itsuki Noda, Tomio Kamada
Massively Multi-Agent Systems II. MMAS 2018. Lecture Notes in Computer Science 11422 130 - 143 2019
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Asymmetric Hidden Node Problem Aware Routing Metric for Wireless Mesh Networks. Reviewed
Keisuke Maesako, Yumi Takaki, Tomio Kamada, Chikara Ohta
Proceedings of IEEE Consumer Communications & Networking Conference (CCNC 2019) 1 - 7 2019
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Takahiro Yamanishi, Takuto Jikyo, Tomio Kamada, Ryo Nishide, Chikara Ohta, Kenji Oyama, Takenao Ohkawa
IEICE Communications Express 2019
Publisher：Institute of Electronics, Information and Communications Engineers ({IEICE})
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Takuto Jikyo, Takahiro Yamanishi, Tomio Kamada, Ryo Nishide, Chikara Ohta, Kenji Oyama, Takenao Ohkawa
IEICE Communications Express 2019
Publisher：Institute of Electronics, Information and Communications Engineers ({IEICE})
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Efficient and reliable packet transfer protocol for wireless multihop bidirectional communications Reviewed
Yumi Takaki, Makoto Ando, Keisuke Maesako, Keisuke Fujita, Tomio Kamada, Chikara Ohta, Hisashi Tamaki
International Journal of Distributed Sensor Networks 14 ( 1 ) 2018.1
Publisher：SAGE Publications Ltd
In wireless multihop bidirectional communication environment, there is a possibility that packet collision and retransmission owing to the hidden node problem decrease efficiency of throughput. The aim of this article is to achieve efficient and reliable packet transmissions in such environments. To do so, we propose a packet transmission scheme named inter-flow network coding with passive acknowledgment. In inter-flow network coding with passive acknowledgment, it is necessary to optimize the encoding latency and to avoid passive acknowledgment packet collision, so we address these issues in this article. Finally, we also confirm that the inter-flow network coding with passive acknowledgment scheme is effective in terms of the collection ratio and delay through simulations.
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A Study for Improvement of Throughput in High-Density Wireless Networks Using Transmitting Opportunity Control Reviewed
KAWASAKI Takahiro, TAKAKI Yumi, KAMADA Tomio, OHTA Chikara
Proceedings of the 32th International Conference on Information Networking (ICOIN 2018) 140 - 145 2018.1
Publisher：IEEE
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Roadmap and research issues of multiagent social simulation using high-performance computing Reviewed
Noda, Itsuki, Ito, Nobuyasu, Izumi, Kiyoshi, Mizuta, Hideki, Kamada, Tomio, Hattori, Hiromitsu
Journal of Computational Social Science 1 ( 1 ) 155 - 166 2018
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Platform design for large-scale artificial market simulation and preliminary evaluation on the K computer Reviewed
Takuma Torii, Tomio Kamada, Kiyoshi Izumi, Kenta Yamada
Artificial Life and Robotics 22 ( 3 ) 301 - 307 2017.9
Publisher：Springer Tokyo
Artificial market simulations have the potential to be a strong tool for studying rapid and large market fluctuations and designing financial regulations. High-frequency traders, that exchange multiple assets simultaneously within a millisecond, are said to be a cause of rapid and large market fluctuations. For such a large-scale problem, this paper proposes a software or computing platform for large-scale and high-frequency artificial market simulations (Plham: /plΛ m). The computing platform, Plham, enables modeling financial markets composed of various brands of assets and a large number of agents trading on a short timescale. The design feature of Plham is the separation of artificial market models (simulation models) from their execution (execution models). This allows users to define their simulation models without parallel computing expertise and to choose one of the execution models they need. This computing platform provides a prototype execution model for parallel simulations, which exploits the variety in trading frequency among traders, that is, the fact that some traders do not require up-to-date information of markets changing in millisecond order. We evaluated a prototype implementation on the K computer using up to 256 computing nodes.
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Collective relocation for associative distributed collections of objects Reviewed
Daisuke Fujishima, Tomio Kamada
International Journal of Software Innovation 5 ( 2 ) 55 - 69 2017.4
Publisher：Taru Publications
The field of parallel computing has experienced an increase in the number of computing nodes, allowing broader applications, including computations that have irregular features. Some parallel programming languages handle object data structures and offer marshaling/unmarshaling mechanisms to transpose them. To manage data elements across computing nodes, some research on distributed collections has been conducted. This study proposes a distributed collection library that can handle multiple collections of object elements and change their distributions while maintaining associativity between their elements. This library is implemented on an object-oriented parallel programming language, X10. The authors assume pairs of associative collections such as vehicles and streets in a traffic simulation. When many vehicles are concentrated on streets assigned to certain computing nodes, some of these streets should be moved to other nodes. The authors' library assists the programmer in easily distributing the associative collections over the computing nodes and collectively relocating elements while maintaining the data sharing relationship among associative elements. The programmer can describe the associativity between objects by using both declarative and procedural methods. They show a preliminary performance evaluation of their library on a Linux cluster and the K computer.
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Overlapping Communication and Computation for Large-Scale Artificial Market Simulation Reviewed
Daisuke Fujishima, Tomio Kamada, Takumi Torii, Kiyoshi Izumi
Proceedings of of 22nd International Symposium on Artificial Life and Robotics (AROB 2017) 708 - 713 2017.1
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Introducing a multithread and multistage mechanism for the global load balancing library of X10 Reviewed
Kento Yamashita, Tomio Kamada
Journal of Information Processing 24 ( 2 ) 416 - 424 2016.3
Publisher：Information Processing Society of Japan
Load balancing is a major concern in massively parallel computing. X10 is a partitioned global address space language for scale-out computing and provides a global load balancing (GLB) library that shows high scalability over ten thousand CPU cores. This study proposes a multistage mechanism for GLB to assign execution stages to tasks and introduces a multithread design into GLB to allow efficient data sharing between CPU cores. The system gives high priority to tasks that are assigned to earlier stages and then proceeds with subsequent stage tasks. When a computing node runs out of tasks at the earliest stage, it requests tasks at the earliest stage from other nodes and awaits responses by processing subsequent stage tasks. When the system identifies the task termination at a certain stage, it executes a reduction operation over nodes. Programmers can define their reduction operations to gather or exchange results of completed tasks. This study provides the implementation method of the extended library and evaluates its runtime overhead using the K computer to a maximum of 256 nodes.
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Platform Design for Large-Scale Artificial Market Simulation and Preliminary Evaluation on the K computer Reviewed
Takuma Torii, Tomio Kamada, Kiyoshi Izumi, Kenta Yamada
Proceedings of 21st International Symposium on Artificial Life and Robotics (AROB 2016) 492 - 497 2016.1
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Redistribution Mechanism for Associative Distributed Collections of Objects Reviewed
Daisuke Fujishima, Tomio Kamada
2016 IEEE/ACIS 15TH INTERNATIONAL CONFERENCE ON COMPUTER AND INFORMATION SCIENCE (ICIS) 583 - 588 2016
Publisher：IEEE COMPUTER SOC
The field of parallel computing has experienced an increase in the number of computing nodes and parallel computing has widened its application to include computations that have irregular features. Some parallel programming languages handle object data structures and offer marshaling/unmarshaling mechanisms to transport them. To manage data elements spread over computing nodes, some research on distributed collections has been conducted. This study proposes a distributed collection library that can handle multiple collections of object elements and change their distributions while maintaining the associativity between their elements. This library is implemented on an object-oriented parallel programming language, X10. We suppose pairs of associative collections such as vehicles and streets in a traffic simulation. When many vehicles are concentrated on streets assigned to certain computing nodes, some of those streets should be moved to other nodes. Our library supports the programmer in easily distributing the associative collections over the computing nodes and re-allocating their elements while maintaining the data sharing relationship among associative elements. The programmer can describe the associativity between objects using both declarative and procedural methods.
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Webアプリケーション向け結合ビューライブラリにおける更新内容の即時反映機能とその実装 Reviewed
畑谷 卓哉, 熊谷 良夫, 鎌田 十三郎
情報処理学会論文誌データベース（TOD） 8 ( 2 ) 68 - 77 2015.6
Publisher：情報処理学会
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Roadmap for Multiagent Social Simulation on HPC Reviewed
Itsuki Noda, Nobuyasu Ito, Kiyoshi Izumi, Tomohisa Yamashita, Hideki Mizuta, Tomio Kamada, Yohsuke Murase, Sachiko Yoshihama, Hiromitsu Hattori
2015 IEEE/WIC/ACM INTERNATIONAL CONFERENCE ON WEB INTELLIGENCE AND INTELLIGENT AGENT TECHNOLOGY (WI-IAT), VOL 3 3 22 - 25 2015
Publisher：IEEE COMPUTER SOC
In this article, we show roadmaps of multiagent social simulation to illustrate directions of technological achievements. Compared with physical simulation, social simulation is still in a phase of establishing models of simulations. We focus three issues, 'undetermined model', 'obscure boundary', and 'incomplete data', and consider a way to overcome these issues by using huge computational powers of high-performance computing (HPC). We pick-up three applications, evacuation, road-traffic, and market, and estimate required computational cost for the real applications.
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Client-Side Joined View Library to integrate CRUD Web services Reviewed
畑谷 卓哉, 熊谷 良夫, 鎌田 十三郎
第7回 Webとデータベースに関するフォーラム予稿集 2014.11
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GLB: Lifeline-based global load balancing in X10 Reviewed International coauthorship
Wei Zhang, Olivier Tardieu, David Grove, Benjamin Herta, Tomio Kamada, Vijay Saraswat, Mikio Takeuchi
PPAA 2014 - Proceedings of the 2014 Workshop on Parallel Programming for Analytics Applications 31 - 40 2014
Publisher：Association for Computing Machinery
We present GLB, a programming model and an associated implementation that can handle a wide range of irregular parallel programming problems running over large-scale dis- tributed systems. GLB is applicable both to problems that are easily load-balanced via static scheduling and to prob- lems that are hard to statically load balance. GLB hides the intricate synchronizations (e.g., inter-node communication, initialization and startup, load balancing, termination and re- sult collection) from the users. GLB internally uses a version of the lifeline graph based work-stealing algorithm proposed by Saraswat et al [25]. Users of GLB are simply required to write several pieces of sequential code that comply with the GLB interface. GLB then schedules and orchestrates the par- allel execution of the code correctly and efficiently at scale. We have applied GLB to two representative benchmarks: Betweenness Centrality (BC) and Unbalanced Tree Search (UTS). Among them, BC can be statically load-balanced whereas UTS cannot. In either case, GLB scales well - achieving nearly linear speedup on different computer archi- tectures (Power, Blue Gene/Q, and K) - up to 16K cores. Copyright © 2014 ACM.
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結合ビューや複数ビューを提供するWebデータ閲覧・編集環境におけるデータ整合性管理
熊谷 良夫, 仙波 雅也, KAMADA TOMIO
第5回データ工学と情報マネジメントに関するフォーラム 論文集 2013.3
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An environment for information integration with editable views of joined Web services
熊谷 良夫, 仙波 雅也, 鎌田 十三郎
第4回データ工学と情報マネジメントに関するフォーラム 論文集 F1-3 (5pages) 2012.3