Reseach on Performance Evaluation Techniques and Tools of Information Systems

1992年，与参与该项目的所有研究人员一起，对宽带综合业务数字网、光纤分布式数据接口(FDDI)、ATM(异步传输模式)的数学建模和性能评估技术的相关理论结果进行了综述。然后，选择一些研究主题一起工作成为可能。在研究人员交流方面，1名加州大学教授应邀访问京都大学，3名日本人访问了加州大学。今年取得的一些具体成果如下：1.考虑到信元的突发性，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推导。它是由一个两状态马尔可夫过程指定的。分析了具有这种到达过程的排队模型，得出了ATM交换机中的信元数目、传输时延和其他性能指标。分析结果是在更宽松的假设…下得到的2.研究了支持多媒体信元的缓冲机制。3.将FDDI中的时令牌协议数学地描述为一个带周期时间约束的轮询模型，并对该模型进行了分析研究。4.提出了一种基于预留机制的树-DTA协议作为随机接入通信网络的协议。研究了协议的性能。5.研究了非阻塞交换在高速分组通信网络中的性能。具体研究了输入缓冲方案和输出缓冲方案对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暂态行为，研究了CRMA(循环预留多址接入)协议。尽管在该协议下运行的网络中，消息到达过程和传输时间之间存在相关性，并且使得该协议的性能分析比其他协议困难得多，但是关于该系统中的消息数量和传输延迟，网络的随机行为已经被阐明。较少

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