State-Dependent Admission Control

The paper is dedicated to a retrial queueing-inventory system with constant retrial rate, heterogeneous customer classes (distinguished by various inventory demands) working under the class- and inventory level-based admission control to a service zone with class-specific servers (one server per class). The replenishment policy is a mixture of the two classical policies, $(s,Q)$ and $(s,S)$. The model is treated by matrix-analytic method in steady- and in transient states in Markov case.