11/06/2014 – Talk by Ivan Stojic

Title: Optimisation of servers with different quality of services
Time: 14:00
Location: Meeting room
Type: Research Result
Speaker: Ivan Stojic

In many applications involving client/server or equivalent architecture, it is possible to vary the quality of services provided by the servers. Dynamic control of the quality of services is an effective mechanism for control of the performance of the system in conditions of varying system load. One of the basic problems involved in applying this mechanism is optimisation of the controlling policy that determines the level of quality of services based on the state of the system. In this seminar, after a brief introduction to Markov chains and basic queueing models, a Markov chain based model of a multiserver queue with processor-sharing discipline and different quality of services is presented. Calculation of the performance indices from the model and the prohibitive complexity of the exact solution are discussed next, motivating the introduction of a simpler model that heuristically approximates the original model and allows for more efficient model solution and optimisation of the controlling policy.