The media streams of a multimedia communication application may traverse through different communication channels. Because of the network delay and jitter, data in these streams sent at the same time may not arrive at a destination simultaneously. In this paper a multimedia synchronization protocol that resynchronizes the media streams is proposed. The protocol inserts extra control cells into the media streams, and aligns the cells at the receiver site. Three synchronization policies, namely, the Drop-Old, the Transmit-Old and the Delayed-Transmit, are introduced to align the control cells. To satisfy the Quality of Service (QOS) specified by an application, the protocol must negotiate an appropriate QOS with the underlying ATM network. For each of the three synchronization policies, the relationship between the specified QOS and the negotiated QOS is derived.>

A key issue in distributed scheduling is selecting appropriate jobs to transfer. A job selection policy that considers the diversity of job behaviors is proposed. A mechanism used in artificial neural networks, called weight climbing, is employed. Using this mechanism, a distributed scheduler can learn the behavior of a job from its past executions and make a correct prediction about whether transferring the job is worthwhile. A scheduler using the proposed job selection policy has been implemented and experimental results show that it is able to learn job behaviors fast, make decisions accurately and adjust itself promptly when system configuration or program behaviors are changed. In addition, the selection policy introduces only negligible time and space overhead.>

An automatic test case generation method for Estelle is proposed. A formal model is introduced to describe the dynamic properties of Estelle specifications so as to verify the difference between the behavior of the specification and the behavior of its models. Based on the difference, an algorithm is presented to produce test cases that can detect such implementation faults. The algorithm can generate test cases not only for single module specifications but also for systems containing multiple modules that run concurrently. In addition, heuristics are suggested to improve the performance of the test case generation process.>

A test case generation method is proposed for the conformance testing of communication protocols. Given a protocol specification and a fault model, both specified by extended finite state machines (EFSMs), the proposed method generates test cases that detect the given faults. A theoretical model is proposed to describe the dynamic properties of EFSMs. Test cases can be generated by analyzing the differences in the dynamic properties between the specification and the fault models.>

A test suite generation method is proposed for conformance testing of communication protocols to solve the problem of generating test sequences for protocol specification models that have memories. A program verification technique called axiomatic semantics, is used to test protocols specified by extended finite state machines (EFSMs). While an EFSM is verified by the technique, observable events are recorded. By carefully manipulating the execution path in EFSM, the observed events can be used to examine the correctness of the protocol implementations.>