Recent advances in queueing networks: a survey with applications to automated manufacturing

Queueing models have been the most widely used analytical modelling tool for performance studies on complex manufacturing systems. Conventional analysis has proceeded along the lines of product form queueing models, and their extensions. Traditional applications of these models have been restricted to the computation of mean values of important performance measures; besides, certain simplifying assumptions have to be made for these models to be applicable. The last decade has witnessed important advances in the applicability of these tradi tional queueing networks, as well as in newer queueing models that exhibit constructs capable of modelling generic issues arising in a real-life manufacturing system. The issues taken up in this pager are: (i) computation of higher moments of performance measures, besides mean values; (ii) the phenomenon of blocking due to limitations of buffer capacities, and (iii) analysis of a network of multiqueues model of an Automated Manufacturing System. We survey the recent advances in these three modelling issues which are of great importance in the manufacturing context, and present analytical models of Automated Manufacturing Systems incorporating these features. Each model is illustrated with a numerical example.