A MAP/PH Perishable Inventory System with an Unreliable Server having Two Modes of Service

This model discusses the impact of variation in service rate at two different levels of inventory on a perishable inventory system with an unreliable server. The primary arrival follows the Markovian arrival process(MAP), and the service time is phase-type distributed. The lifetime of items in the inventory is subject to an exponential distribution. A retrial facility with an infinite orbit is equipped with the system. The service rate modification is done at two different inventory levels. We compare the optimal profits in both cases and study the impact of various parameters on the system.