| Project/Area Number |
12680422
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
情報システム学(含情報図書館学)
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| Research Institution | Tokyo Denki University |
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Principal Investigator |
MAKOTO Takizawa Tokyo Denki Universiity, School of Science and Engineering, Professor, 理工学部, 教授 (80188119)
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| Co-Investigator(Kenkyū-buntansha) |
KATSUYA Tanaka Tokyo Denki University, School of Science and Engmeering,Resarch Assistant, 理工学部, 助手 (70318161)
桧垣 博章 東京電機大学, 理工学部・情報システム工学科, 助教授 (70287431)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | group communication / multimedia communications / object-oriented systems / flexible systems / QoS (quality of service) / causally ordered delivery. / 因果順序配送 / やわらかいグループ通信 / オブジェクト / 分散型システム / グループ通信プロトコル / マルチメディア / Qos(サービス品質) |
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| Research Abstract |
Distributed applications like virtual-conferences are realized by cooperation of multiple processes which are interconnected by high-speed communication networks. The communication network supports reliable communication. A group is composed of multiple processes. A process sends messages to multiple processes and receive messages from multiple processes in a group. In the group, messages are requited to be causally delivered to the destination processes in addition to reliable, efficient delivery of messages. We define a novel precedent relation of multimedia objects exchanged among application processes. The relation is named object-precedent (O-precedent) one. Only subset of messages are required to be causally ordered according to the O-precedent relation while all the messages are tried to be causally ordered by traditional group protocols. Thus, our group protocol implies less communication and computation overheads than the traditional protocols. In distributed applications, multimedia objects like video and voice objects are exchanged among multiple processes in addition to traditional text data. In the multimedia communication, quality of service (QoS) of multimedia objects are required to be supported for applications. QoS supported by the underlying communication network is changed due to congestions and communication foults. We also discusses the group communication protocol which support flexibility for applications. In the protocol, most suitable functions of transmission, retransmission, and confirmation are selected so as to satisfy QoS required by applications in change of network service.
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