Holding buses to scheduled departure time at timepoints involves a tradeoff between reliability and speed, with impacts on user and operating cost. Two new measures of user cost, excess waiting time and potential travel time, are proposed. They relate to the early extreme of a bus’s departure time distribution from a passenger’s origin stop, and the late extreme of a bus’s arrival time distribu...

We consider the order ful ̄llment process of a customized capital equipment supplier. Prior to receiving a ̄rm purchase order from the customer, the supplier receives a series of shared forecasts, which are called `soft orders'. Facing a stochastic internal manufacturing lead-time, the supplier must decide at what time to begin the ful ̄llment of the order. This decision requires a trade-o® betwe...

We analyze two scheduling problems for a queueing system with a single server and two customer classes. Each class has its own renewal arrival process, general service time distribution, and holding cost rate. In the first problem, a setup cost is incurred when the server switches from one class to the other, and the objective is to minimize the long-run expected average cost of holding custome...

Stochastic flexible flow shop scheduling problem (SFFSSP) is one the main focus of researchers due to the complexity arises from inherent uncertainties and also the difficulty of solving such NP-hard problems. Conventionally, in such problems each machine’s job process time may encounter uncertainty due to their relevant random behaviour. In order to examine such problems more realistically, fi...

In this paper we consider the problem of allocating bandwidth to two transmitters/queues with arbitrary arrival processes, so as to minimize the total expected (discounted) holding cost of backlogged packets in the system over a finite (infinite) horizon. The bandwidth is in the form of time slots in a TDMA schedule. Allocation decisions are made based on the queue backlog information, which is...

This paper presents a reliability-based optimization model of inspection, maintenance, and replacement for a system of several highway bridges. The objective in the formulation is to minimize the total expected social cost, including the expected cost of failure. The frequency of inspections is included as a decision variable. The probability of failure is explicitly taken into account in the c...

Among both inventory theorists and practitioners, it is common use to include an opportunity cost rate in the holding cost rate. In that way, the cost of capital can be roughly incorporated in an average cost (AC) inventory model. The traditional way for calculating the opportunity cost rate is to multiply the interest rate (or discount rate) by the marginal cost for producing/ordering an item....