Reseach on Performance Evaluation Techniques and Tools of Information Systems

1992年，与项目有关的所有研究人员一起，对宽带ISDN、FDDI（光纤分布式数据接口）、ATM（异步传输模式）的数学建模和性能评估技术的理论结果进行了审查。然后就可以选择一些研究课题一起工作。在研究人员的交流方面，京都大学邀请了加州大学的一位教授，日本的三位教授访问了加州大学。今年取得的一些具体成果如下：1.在考虑突发性的情况下，对支持多媒体通信的ATM网络中的信元到达过程进行了数学描述。它是由一个两状态马尔可夫过程。本文分析了一个具有这种到达过程的ATM交换模型，导出了ATM交换机中信元的数目、传输延迟和其它性能指标。分析结果是在较宽松的条件下得到的 ...更多信息 本文对FDDI中的定时令牌协议进行了分析，将其表示为一个具有周期时间约束的轮询模型，并对该模型进行了扩展，引入了优先级机制。具有预留方案的DTA已经被提出作为用于随机接入通信网络的协议。研究了无阻塞交换机在高速分组通信网络中的性能。详细研究了输入缓冲区和输出缓冲区对网络吞吐量和丢包率的影响。6.分析了流量控制下高速分组通信网络的瞬态行为，研究了CRMA（Cyclic Reservation Multiple Access）协议。虽然，在这个协议下运行的网络中，消息到达过程和传输时间之间的相关性的出现，并使协议的性能分析比其他协议更困难，th随机行为的网络已经澄清了关于th系统中的消息的数量和传输延迟。少

In 1992, the theoretical results related to the mathematical modelling and performance evaluation technique for Broadband ISDN, FDDI(Fiber Distributed Date Interface), ATM(Asynchronous Transfer Mode were Reviewed in corporation with all the researchers involved in project. Then it became possible to select some research topics to work on together. As for the exchange of researchers, one professor of University of California was invited to Kyoto Unibersity and three from Japan visited University of California.Some of specific achievement which carried out this year wear as follows.1.Cell arrival process in ATM networks supporting multimedia communication has been mathematically formulated taking its burstiness into account. It is specified by a two-state Markov process. A queuein model with this arrival process has been analysed to derive the number of cells in ATM switches transmission delay and other performance measures. The analytical result as been obtained unde more relaxed assump … More tion than before and includes several important queueing theoretical results.2.Buffering schemes to accomodate cells from multimedia sources have n investigated.3.Timed token protocol in FDDI has been mathematically formulated as a polling model with cycle tim constraints and analytically investigated Furthermore the model has been extended to incorporate priority mechanism.4.Tree-DTA with reservation scheme has been proposed as a protocol for random access communication networks. The performance of protocol has been investigated.5.Performance of non-blocking switches in high speed packet communication networks has been considered. Specifically, input buffer scheme and output buffer scheme have been elaborately investigated to clarify its effect on the throughput and packet loss rate.6.The transient behaviour of a high speed packet communication network under a flow control has been analysed.CRMA(Cyclic Reservation Multiple Access) protocol has investigated. Although, in the network operated under this protocol, correlation between message arrival process and transmission time arise and makes the performance analysis of the protocol much more difficult that other protocols, th stochastic behavior of the network has been clarified with respect to the number of messages in th system and the transmission delay. Less