A predictive-maintenance structure for a gradually deteriorating single-unit system (continuous time/continuous state) is presented in this paper. The proposed decision model enables optimal inspection and replacement decision in order to balance the cost engaged by failure and unavailability on an infinite horizon. Two maintenance decision variables are considered: the preventive replacement t...

Today’s, the transportation facilities such as terminals, street, bridge, etc, represent the major investment in highway network. Every year tremendous resources should be invested to maintain these facilities. Among them, the Bridge Management System (B.M.S.) has been necessitated by large imbalance between extensive bridge repair and maintenance needs and limited available budget. So the main...

The aim of this paper is to develop an optimization model for quality improvement by considering quality investment in rework policies and supply chain profit sharing. To improve product’s quality, the decision of process target and its tolerance is important since it directly affects the defective rate, manufacturing cost, and loss to customer due to the deviation of product from its specifica...

In this paper we consider a system consisting of a supplier with a single processing unit, a repair center, and a retailer with Poisson demand. We assume that the retailer applies one-for-one ordering policy with backorders for his inventory control. The retailer’s orders form a queue in the supplier processing unit. We also assume that a certain fraction of the products produced by the supplie...

Artificial neural network (ANN) based methods have been extensively investigated for equipment health condition prediction. However, effective condition based maintenance (CBM) optimization methods utilizing ANN prediction information are currently not available due to two key challenges: (1) ANN prediction models typically only give a single remaining life prediction value, and it is hard to q...

In this article, we survey machine repair problems (MRP) with an emphasis on historical developments of queuing models of practical importance. The survey proceeds historically, starting with developments in 1985, when the first published review on machine interference models appeared. We attempt to elaborate some basic MRP models of the real life congestion situations. The brief survey of some...

We examine repairable systems with a continous state space and partial repair options, carried out at fixed times n = 1, 2, .... Every time interval [n, n + 1) there is a manufacturing cost and a repair cost. These cost functions are not restricted to the class of bounded functions in this study. Conditions are found under which a control-limit replacement policy minimizes the discounted cost. ...

This paper provides a replacement policy for warranty products with different failure rate from the consumer’s viewpoint. Assume that the product is replaced once within a finite planning horizon, and the failure rate of the second product is lower than the failure rate of the first product. Within warranty period (WP), the failed product is corrected by minimal repair without any cost to the c...

We consider a randomized policy to control the M/G/1 queueing system with an unreliable server, second optional service and general startup times. The server is subject to breaking down according to a Poisson process, and the repair time obeys a general distribution. All arrived customers demand the first required service, and only some of the arrived customers demand the second optional servic...

This paper proposes the use of discrete stochastic approximation (DSA) algorithm for a crosslayer adaptive modulation problem in wireless communications. In this system, the throughput in the physical (PHY) layer and quality of service (QoS) incurred by the queueing effects in the data link layer are required to be optimized simultaneously and in the long run. By assuming Markov decision proces...