| Project/Area Number |
10480084
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
社会システム工学
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KIMURA Toshikazu Hokkaido Univ., Graduate School of Economics, Professor, 大学院・経済学研究科, 教授 (50143649)
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| Co-Investigator(Kenkyū-buntansha) |
OKAMURA Hiroyuki Hiroshima Univ., Faculty of Eng., Instructor, 工学部, 助手 (10311812)
DOHI Tadashi Hiroshima Univ., Faculty of Eng., Associate Professor, 工学部, 助教授 (00243600)
OSAKI Shunji Hiroshima Univ., Faculty. of Eng., Professor, 工学部, 教授 (10034399)
TAKAHASHI Yoshitaka Waseda University. Faculty of Commerce, Associate Professor, 商学部, 助教授
KAIO Naoto Hiroshima Shudo Univ., Dept.of Economic Infomatics, Professor, 経済科学部, 教授 (80148741)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Performance Evaluation / Reliability / Stochastic Models / Diffusion Approximations / Queues / Database Systems / Switching Systems / 持ち行列 / 情報通信システム |
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| Research Abstract |
This research deals with the design and control of highly reliable computer and communication systems. The main purpose is to develop new mathematical models for these systems by uniting performance evaluation and reliability analysis. For this purposes, we obtained the following results :
(1)For queues formulated as continuous-time Markov processes, Kimura developed an accurate diffusion approximation model being consistent with the exact results for those processes. This model has a significant value in the sense that the class of target queues is extended and that the approximations are expressed in explicit forms. This model was first applied to GI/G/s/s+r queue as a special case, and then to more general cases ; see the data #4, #10 and #11 in the report. The associated results for M/G/s/s+r queue were summarized in a separate paper ; see the data #12.
(2)Okamura, Dohi, Kaio and Osaki have extended the diffusion model for a controlled queue with N-Policy, which was developed by Kimura in 1981, to two different directions : The one is a queue with vacation times and the other is a queue with breakdowns, which are summarized in two papers ; see the data #1 and #9.
(3)Dohi, Kaio and Osaki studied an optimal policy for recovering failures in database systems by checkpointing and rollback strategies ; see #2 and #6. Also, Dohi and Osaki analyzed recovering behavior in distributed systems by using a generalized stochastic Petri nets ; see #3. All of these results certainly realized the purpose of this research.
(4)Okamura, Dohi and Osaki developed a stochastic model for computer systems with automatic sleep scheduling, which maximizes the effectiveness of electric power ; see the data #5 and #8.
(5)Takahashi applied the diffusion model to study trunk reservation effects in a switching system with multiple servers and batch arrivals ; see the data #7.
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