We consider an inventory-production system where items deteriorate at a constant rate. The objective is to develop an optimal production policy that minimizes the cost associated with inventory and production rate. The inventory problem is first modeled as a linear optimal control problem. Then linear quadratic regulator (LQR) technique is applied to the control problem in order to determine th...

In this paper we study an assembly system which supplies an end-product inventory. We allow assembly operation times to be G.I. distributed and analyze the system as a Markov renewal process, deriving a closed-form expression for long-run Palm probabilities of both kit and end-product inventory positions. We then present a numerical procedure to obtain various performance measures using the mat...

Seasonal items like fruits, fish, winter cosmetics, fashion apparel, etc. generally exhibits different demand patterns at various times during the season. Production and inventory planning must reflect this property for cost effectiveness and optimization of resources. This paper presents two production-inventory models for perishable seasonal products that minimize total inventory costs. The m...

In this paper, we study a production-inventory systems with finite production capacity and fixed setup costs. The demand process is modeled as a mixture of a compound Poisson process and a constant demand rate. For the backlog model we establish conditions on the holding and backlogging costs such that the average-cost optimal policy is of (s, S)-type. The method of proof is based on the reduct...

in this paper, the study deals with the lead time and setup reduction problem in the vendor-purchaser integrated inventory model. the cost of capital (i.e., opportunity cost) is one of the key factors in making the inventory and investment decisions. lead time is an important element in any inventory system. the proposed model is presents an integrated inventory model with controllable lead tim...

In this paper, a finite-source retrial queueing system with twoway communication is investigated the help of simulation program own. If randomly arriving request from finds single server idle its service starts immediately, otherwise it joins an orbit where generates retrial/repeated calls after random time. To increase utilization when becomes time outgoing called for infinity source. Upon arr...

This paper considers an M/G/1 retrial G-queue with general retrial times, in which the server is subject to working breakdowns and repairs. If the system is not empty during a normal service period, the arrival of a negative customer can cause the server breakdown, and the failed server still works at a lower service rate rather than stopping the service completely. Applying the embedded Markov...

We consider basic M/M/c/c (c ≥ 1) retrial queues where the number of busy servers and that of customers in the orbit form a level-dependent quasi-birth-and-death (QBD) process with a special structure. Based on this structure and a matrix continued fraction approach, we develop an efficient algorithm to compute the joint stationary distribution of the numbers of busy servers and retrial custome...

Multi-objective inventory models of deteriorating items have been developed with vague and imprecise information about available storage area. Here, the objectives are (i) to maximize the profit, (ii) to minimize the wastage cost due to deterioration and (iii) to minimize the total production cost. These objectives are also fuzzy in nature. In these models, production rate is a decision variabl...

A multi-class c-server retrial queueing system in which customers arrive according to a class-dependent Markovian arrival process (MAP) is considered. Service and retrial times follow class-dependent phase-type (PH) distributions with the further assumption that PH distributions of retrial times are acyclic. A necessary and sufficient condition for ergodicity is obtained from criteria based on ...