The two-machine permutation flowshop scheduling problem to minimize makespan or total completion time criterion is addressed where setup times are considered to be separate from processing times. Setup times are relaxed to be random variables as opposed to the common assumption in the literature that setup times are exactly known (deterministic) in advance. The probability distributions of setu...

Radiation therapy is one of the commonly used cancer therapies. The radiation treatment poses atuning problem: it needs to be effective enough to destroy the tumor, but it should maintain the func-tionality of the organs close to the tumor. Towards this goal the design of a radiation treatment has to becustomized for each patient. Part of this design are intensity matrices that defi...

In this paper a general shop scheduling problem with sequence dependent setup times arid alternative r[.~ sources is considered, where optimization criteria are both makespan and sum of setup times. Two cooperative models for the problem based on Constraint Programming arc proposed. The first is used to model the scheduling constraints, while the second is a muhipath model used for setup optimi...

Hybrid flow-shop or flexible flow shop problems have remained subject of intensive research over several years. Hybrid flow-shop problems overcome one of the limitations of the classical flow-shop model by allowing parallel processors at each stage of task processing. In many papers the assumptions are generally made that there is unlimited storage available between stages and the setup times a...

In this paper, a new mathematical model for the problem of job scheduling in virtual manufacturing cells (VMC) is presented to minimizing the completion time of all jobs. Sequence dependent setup times of machines is considered and lot-streaming is possible. In Virtual manufacturing cells, each job has a different processing path and there is a set of machines for processing each operation. The...

This investigation deals with MX/G/1 queueing model with setup, bulk- arrival, loss-delay and balking. The provision of second optional service apart from essential service by an unreliable server is taken into consideration. We assume that the delay customers join the queue when server is busy whereas loss customers depart from the system. After receiving the essential service, the customers m...

We consider the problem of allocating a single server to families of jobs with random service times and due dates. Furthermore, a setup is required when the server switches from one job family to another. We address the problems of minimizing expected weighted ow time, expected maximum lateness, and total weighted tardiness with emphasis on problems for which it is assumed that each family can ...

This paper presents different methods for solving parallel machine scheduling problems with precedence constraints and setup times between the jobs. Limited discrepancy search methods mixed with local search principles, dominance conditions and specific lower bounds are proposed. The proposed methods are evaluated on a set of randomly generated instances and compared with previous results from ...