Modeling And Performance Analysis Of Heterogeneous Distributed Real-time Systems

With the advance of distributed computing and development of computer network, the application and design technogoly of distributed system become the focus point in computer science research field. Also the application of distributed real-time system enters people' s daily life, including virtual reality, tele-teaching, tele-medicine, VOIP and so on.Distributed real-time system demands strict requirement of time and QoS, therefore calls for high quality tools and technologies to design, implement and test. Fuzzy-Timing Petri Net(FTN) employ fuzzy set theory to express uncertain or subjective timing information, by each transition being associated with a firing interval, we get Extended Fuzzy-Timing Petri Net(EFTN). Extended Fuzzy-Timing Petri Net(EFTN) is a formal model for modeling and analysis of network-based real-time systems, Petri Net' s mathematical theory basis will ensure the reliability and correctness of concurrent systems.The thesis detailedly introduces the definition of FTN and EFTN, model check method, net-reduction technology, using CPN Tools to simulate EFTN. Distributed multimedia systems support the integration and coordination of audio, video, text and numeric data originating from databases or high-speed networks. In distributed multimedia synchronization involving, asynchronous communicatina with heterogeneous sources and media, not all media segments have a prior known presentation time-durations, multimedia synchronization among several distributed and independent sources may include uncertain temporal requirements. So we need a temporal model which can deal with this temporal uncertainties. This thesis models and analyses distributed multimedia synchronization by EFTN. In distributed multimedia system, Resource Reservation Protocol is an important protocol to ensure Quality of Service. Some parts of the document may be ambiguous, difficult to understand and imprecise;also the cost for fixing errors in the protocolfound in the implementation can be high. The formal specification and verification of RSVP clarifies the problem;also finding errors in time whithout cost. The thesis introduces the Resource Reservation Protocol, models the network using CPN Tools, analyses time parameter and the performance. In succession introduces an example of distributed multimedia system—Remote Education System, and models the session control modul and simply analyses the model. Finally gives some directions of future work.