Queueing models can be useful in solving many complex reliability problems. Component failures are usually interpreted as the arrival of customers and the repair or replacement of failed components is typically associated with the service facility. A distinctive characteristic of queues in reliability is that requests for service are usually generated by a finite customer population because, in...

A case-referent study of 345 prostate cancer cases and 1,346 referents was carried out in the Netherlands to investigate the relationship between work environment and prostate cancer risk. Cases were selected from the Cancer Registry of the Comprehensive Cancer Centre IKO. Referents (men diagnosed with benign prostate hyperplasia) were recruited with assistance of the pathology laboratories in ...

In an occupational mortality analysis of 486,000 adult male death records filed in Washington State in the years 1950-1982, leukemia and the non-Hodgkin's lymphomas show increased proportionate mortality ratios (PMRs) in workers employed in occupations with intuitive exposures to electromagnetic fields. Nine occupations of 219 were considered to have electric or magnetic field exposures. These ...

We study a variant of the maximum coverage problem which we label the maximum coverage problem with group budget constraints (MCG). We are given a collection of sets S = {S1, S2, . . . , Sm} where each set Si is a subset of a given ground set X. In the maximum coverage problem the goal is to pick k sets from S to maximize the cardinality of their union. In the MCG problem S is partitioned into ...

Spina bifida aperta are complex congenital malformations resulting from failure of fusion in the spinal neural tube during embryogenesis. Despite surgical repair of the defect, most patients who survive with spina bifida aperta have a multiple system handicap due to neuron deficiency of the defective spinal cord. Tissue engineering has emerged as a novel treatment for replacement of lost tissue...

We study a situation where several independent service providers collaborate by complete pooling of their resources and customer streams into a joint service system. These service providers may represent such diverse organizations as hospitals that pool beds, call centers that share telephone operators, or maintenance firms that pool repairmen. We model the service systems as Erlang delay syste...

This paper deals with the G/G/R machining system consisting of M operating machines as well as S cold standbys. The concepts of balking and reneging are incorporated which make our model more versatile to deal with real time systems. The broken-down machines are sent to repair facilities consisting of R permanent repairmen. The failure times and repair times are generally identical and independ...

The importance in promoting, sustaining industries, manufacturing systems and economy through reliability measurement has become an area of interest. The profit of a system may be enhanced using highly reliable structural design of the system or subsystem of higher reliability. On improving the reliability and availability of a system, the production and associated profit will also increase. Re...

An availability model is developed to optimize the availability of a series repairable system with multiple k-out-of-n subsystems in this paper. There are two types of decision variables that determine the system designer’s decision to allocate the number of repairmen and to allocate the number of redundant components in each subsystem in the presence of weight, volume and cost constraint...

Reliability optimization problem has a wide application in engineering area. One of the most important problems in reliability is redundancy allocation problem (RAP). In this research, we worked on a RAP with repairable components and k-out-of-n sub-systems structure. The objective function was to maximize system reliability under cost and weight constraints. The aim was determining optimal com...