Consider the production of a single consumable product that is fabricated in a process of stages that is subject to an uncertain environment. There are a number of workstations on each stage that have different operating parameters. The workstations are subject to the discrete events of repair, failure, and preventive maintenance that generate a jump in the state of the system. Between each sta...

Rules governing scheduling and sequencing have accumulated overtime, driven by the manufacturing firms quest for improved operations against key performance metrics. While lead time dictates the need to preserve a focus on manufacturing efficiency, these needs must be balanced with demand-driven requirements especially at the process level, based on the finite capacity that is true of real syst...

In this paper we consider a closed queueing system in which N customers circulate between two stations. One station contains customers which are functioning, the other is a single server queue containing failed customers. Each functioning customer can fail, independently of the other customers, and when that happens it arrives at the queue. The repairman or server can repair the broken customer...

We consider the optimal scheduling of a nite capacity shuttle in a two node network with imperfect information. When shuttle trips do not depend on the number of passengers carried, we prove optimality and monotonicity of threshold policies. We derive conditions for dispatching which reduce the computational eeort required to compute an optimal threshold policy. We provide a counterexample to t...

in this paper, a new approach to overlapping operations in job shop scheduling is presented. in many job shops, a customer demand can be met in more than one way for each job, where demand determines the quantity of each finished job ordered by a customer. in each job, embedded operations can be performed due to overlapping considerations in which each operation may be overlapped with the other...

Background and Objectives: Operating room (OR) scheduling is key to optimal operating room productivity. The significant uncertainty associated with surgery duration renders scheduling of surgical operation a challenging task. This paper proposes a novel computational stochastic model to optimize scheduling of surgeries with uncertain durations. The model considers various surgical operation co...

Scheduling tasks on a radar system can be modeled as a multioperation scheduling problem where tasks are composed of two operations separated by a fixed duration. Tasks have to be scheduled on a single machine and the aim is to minimize the makespan. The complexity status of this problem has been settled for various cases but the one where all tasks are identical remains open. This paper aims a...

Optimization of timing behaviour of manufacturing systems can be regarded as a scheduling problem in which tasks model the various production processes. Typical for many manufacturing systems is that tasks or collections of tasks can be associated with manufacturing entities, which can be structured hierarchically. Execution of production processes for several instances of these entities result...

In this paper a class of queueing model is studied where servers break down but the information regarding breakdowns is not immediately available. As such, jobs continue to arrive into a queue for some period after service has ceased. These queues have finite capacity, therefore there is also the possibility that queues become full causing jobloss. The effect of the duration of any delay on inf...

We consider a finite-population queueing system with heterogeneous classes of customers and a single server. For the case of nonpreemptive service, we fully characterize the structure of the server’s optimal service policy that minimizes the total average customer waiting costs. We show that the optimal service policy may never serve some classes of customers. For those classes that are served,...