This paper investigates the effects of preventive-maintenance cost functions on the optimal preventive-maintenance policy for a leased product with Weibull life-time distribution. During the lease period, any product failures are rectified by minimal repairs and may incur a penalty to the lessor, if the time duration for performing a minimal repair exceeds a pre-specified time limit. To reduce ...

In this paper we analyze the consistency and stability properties of Runge-Kutta discrete adjoints. Discrete adjoints are very popular in optimization and control since they can be constructed automatically by reverse mode automatic differentiation. The consistency analysis uses the concept of elementary differentials and reveals that the discrete Runge-Kutta adjoint method has the same order o...

Article history: Received 1 April 2011 Received in revised form 23 September 2011 Accepted 24 September 2011 Available online 2 October 2011

The paper deals with the continuous-time BMAP/G/1 queue with multiple vacations and with its application to IEEE 802.16e sleep mode. The lengths of the vacation periods have general distribution and they depend on the number of preceding vacations (dependent multiple vacation). We give the expressions for the vector generating function of the stationary number of customers and its mean. Moreove...

Most existing condition based maintenance (CBM) work reported in the literature only focuses on determining the optimal CBM policy for single units. Replacement and other maintenance decisions are made independently for each component, based on the component’s age, condition monitoring data and the CBM policy. In this paper, a CBM optimization method is proposed for multi-component systems, whe...

In this paper, an integrated approach for production scheduling and maintenance is proposed for a multi-component system. The model in this paper is based on the selective maintenance policy. The objective is to obtain a minimum cost solution with availability, allowable maintenance time as constraints. The optimization procedure using the proposed integrated approach results into maintenance d...

This paper analyzes renewal input state dependent queue with $N$- policy wherein the server takes exactly one vacation. Using the supplementary variable technique and recursive method, we derive the steady state system length distributions at various epochs. Various performance measures has been presented. Finally, some numerical  computations in the form of graphs are presented to show the par...

Optimal control problems are applied to a variety of dynamical systems with random law motion. In this paper we show that the degradation processes defined on discrete set intermediate states also suitable for formulating and solving optimization finding an appropriate optimal policy. Two models considered in paper: time instantaneous failure preventive maintenance. both cases, threshold-based ...

A complex multi-state redundant system with preventive maintenance subject to multiple events is considered. The online unit can undergo several types of failure: both internal and those provoked by external shocks. Multiple degradation levels are assumed as external. Degradation observed random inspections and, if they major, the goes a repair facility where carried out. This composed single r...