| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
This research deals with the design and control of modern information highways. The main purposes are (i) to develop a continuous model as a network design tool, and (ii) to examine the model efficiency in controlling networks. To these purposes, I obtained the following results.
1.Under general assumptions on the arrival and service processes of packets in a network, I obtained a new diffusion model approximating the queue-length process in each node of the network, which is called the BD-based diffusion model. The new model has significant advantage over others on the accuracy, that is, it is consistent with any known exact results, whereas the previous diffusion models are not. Also, the new model can be easily applied to some network design problems such as optimal buffer design, because the approximate queue-length distribution is given in an explicit form. This result is summarized in a paper under submission ; see the data #2 in the report.
2.I applied the BD-based diffusion model to a finite-capacity multi-server queue, obtaining an approximate queue-length distribution that is consistent with the general arrival and exponential service case. This result is summarized in a paper under submission ; see the data #3 in the report.
3.Assuming pseudo local balance in each node and using the BD-based diffusion model, I developed a continuous model for a general closed queueing network. This result have been presented in the 1997 Spring National Meeting of the OR Society of Japan ; see the data #4 in the report.
4.To compare the BD-based diffusion model with the previous ones, I surveyed diffusion models for queues in computer/communication systems. It is found from this survey that the BD-based diffusion model is also useful in the design and control of computer systems such as data-base management problems. The survey and related results are summarized in two separate papers ; see the data _<5 and >6 in the report.
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