Multi-class service systems are of increasing importance in the practical modelling world but present a significant challenge for analysis. Most results to date concerning the optimal dynamic control of such systems have assumed holding cost rates to be linear in the number of customers present. In response to arguments that such an assumption is often inappropriate, we develop an index heurist...

This paper aims to develop a deteriorated bridge maintenance strategy that ensures the safe operation of steel structures and minimizes total risk. Five common failure modes are considered for bridge: flexure, shear, deflection, fatigue girder, chloride attack concrete deck. Time-dependent system reliability analyses carried out find probability under these modes. Risk-cost optimization is then...

The goal of this paper is to provide new evidence on how the zero-interest rate policy implemented by the Bank of Japan has affected the sensitivity of money demand with respect to the opportunity cost of holding money. To the empirical ends of the analysis, the study makes use of the univariate conditional autoregressive value-at-risk (CAViaR) estimator to obtain robust quantile measures. The ...

We consider the problem of allocating a single server to a system of queues with Poisson arrivals. Each queue represents a class of jobs and possesses a holding cost rate, general service distribution, and general setup time distribution. The objective is to minimize the expected holding cost due to the waiting of jobs. A setup time is required to switch from one queue to another. We provide a ...

We study the tradeoff between efficiency and service quality in tandem systems. We reward efficiency by assuming that a revenue is earned each time a job is completed, and we penalize poor service quality by incorporating positive holding costs. We study the dynamic assignment of servers to tasks with the objective of maximizing the long-run average profit. For systems of arbitrary size, genera...

In Hajek's arrival routing problem, customers are routed to one of n queues to minimize average holding cost. Interarrival and service times are exponentially distributed. We solve the associated. The optimal uid policy tells us the asymptotic slopes of the switching surfaces in the original problem when the queues are large. If these slopes are nonzero, then numerical tests indicate that the u...

the term ‘deteriorated texture’ gives all experts as well as ordinary people almost the sameimpression. despite common points in images, the differences put iran cities in different categories based on deteriorated textures. this classification not only has negative effect on the audience from mental point of view but causes various problems for the experts in determining interference method. f...

The deal for industrial companies is to satisfy their customers with the best quality, the most reliable lead times, and the lowest costs. One of the keys to achieve it is in the inventory control in the Supply Chain. Moreover, it is mandatory to possess necessary components in order to produce the requested products by the due date. But, as the components lead time is an unpredictable paramete...