The joint optimisation of production scheduling and maintenance planning can significantly decrease interruptions (or stoppages) and, simultaneously, improve stability enhance the reliability availability equipment machines. This paper studies schedules CBM plans in a parallel-machine setting. machines are subject to deterioration, unexpected breakdowns, deterioration-based failures. is modelle...

The parallel machine replacement problem consists of finding a minimum cost replacement policy for a finite population of economically interdependent machines. In this paper, we formulate a stochastic version of the problem and analyze the structure of optimal policies under general classes of replacement cost functions. We prove that for problems with arbitrary cost functions, there can be opt...

We consider the parallel-machine scheduling problem in which the processing time of a job is a simple linear increasing function of its starting time. The objective is to minimize the total completion time. We give a fully polynomial-time approximation scheme (FPTAS) for the case with m identical machines, where m is fixed. This study solves an open problem that has been posed in the literature...

Since new drinking water regulations were implemented in England and Wales in 2000, cryptosporidiosis has been significantly reduced in the first half of the year but not in the second. We estimate an annual reduction in disease of 905 reported cases and approximately 6,700 total cases.

This longitudinal study examined the effect of the birth of the 1st child on relationship functioning using data from 218 couples (436 individuals) over the course of the first 8 years of marriage. Compared with prebirth levels and trajectories, parents showed sudden deterioration following birth on observed and self-reported measures of positive and negative aspects of relationship functioning...

We study a single batching machine scheduling problem with transportation and deterioration considerations arising from steel production. A set of jobs are transported, one at a time, by a vehicle from a holding area to the single batching machine. The machine can process several jobs simultaneously as a batch. The processing time of a job will increase if the duration from the time leaving the...

Asexual species accumulate deleterious mutations through an irreversible process known as Muller's ratchet. Attempts to quantify the rate of the ratchet have ignored the role of temporal environmental heterogeneity even though it is common in nature and has the potential to affect overall ratchet rate. Here we examine Muller's ratchet in the context of conditional neutrality (i.e., mutations th...

Leli and Filskov (1979) reported cross-validated classification accuracy that equalled 83% for a discriminant function derived on two measures of intellectual deterioration. This investigation made a preliminary assessment of the clinical utility of this function through a clinical-actuarial classification paradigm. Wechsler-Bellevue Intelligence Scale Form I protocols from 12 nonpsychotic noni...