Simulation comparison of collaboration protocol-based testing models

This paper uses a simulation modelling approach to investigate two collaboration protocols; timeout and frequent request collaboration protocols. The models presented here are very generic and can be adopted in general testing environments with a single tester shared by many types of jobs and with the repair process. This research presents different results from earlier studies, while addressing their misleading simplifying assumptions that are a common pitfall in practice. The two collaboration protocols are redefined based on the results. The timeout protocol improved system performance by collaborating with the shortest processing time (SPT) rule in the gamma repair time distributions with left biased shape. This collaboration is simple to implement and does not require the parameter estimation that is often a drawback of most heuristics for the combination of dispatching rules. The frequent service request dispatching rule showed as good performance as the SPT rule with respect to overall mean flow time in this problem. Research is being continued to further investigate the properties of the timeout collaboration protocol with various factors.