Age-replacement is one of the most commonly usedmaintenance policies based on preventive action to prevent system failure. Inmany age-replacement settings, it assumed that maintenance time can beignored since short compared with operation time. However, maintenance,especially corrective maintenance, may take a non-negligible amount dueto various factors such as ordering replacement parts, equip...

farm machinery managers often need to make complex economic decisions on machinery replacement. repair and maintenance costs can have significant impacts on this economic decision. the farm manager must be able to predict farm machinery repair and maintenance costs. this study aimed to identify a regression model that can adequately represent the repair and maintenance costs in terms of machine...

background osteoarthritis (oa) is a multifactorial, disabling and degenerative disease that worsens with age and affects patient’s health-related quality of life (hrqol). objectives the current study aimed to assess if age and comorbidities have an influence on knee oa and knee replacement outcome before and after the surgery. methods a quasi-experimental intervention study was conducted on a s...

juvenile idiopathic arthritis is the leading cause of hip replacement in young children. however, arthroplasty in this population is challenging with several concerns about quality of the growing bone, young age for revision surgery, and difficulties in potential several revisions. in this study we introduce a case of a 12-year old who is one of the youngest patients to undergo revision hip art...

8 Abstract This research presents a bus fleet replacement optimization model to 9 analyze vehicle replacement decisions when there are competing technologies. The 10 focus of the paper is on sensitivity analysis. Model properties that are useful for 11 sensitive analysis are derived and applied utilizing real-world data from King 12 County (Seattle) transit agency. Two distinct technologies, di...

Age replacement of technical units has received much attention in the reliability literature over the last four decades. Mostly, the failure time distribution for the units is assumed to be known, and minimal costs per unit of time is used as optimality criterion, where renewal reward theory simplifies the mathematics involved but requires the assumption that the same process and replacement st...

In this paper we use the Generalised Population Based Incremental Learning (GPBIL) in order to find profit-maximizing strategies for the Artificial Payment Card Market (APCM). The artificial market has modeled explicitly a multidimensional consumers’ and merchants’ demand for payment instruments. Given the complex shape of the demand, we have found that the GPBIL effectively explores the areas ...

esults: Women in the CBT NRT arm were almost three times more likely than women in the CBT-only arm to have biochemically validated cessation at both pregnancy time points (after 7 weeks: 24% vs 8%, p 0.02; at 38 weeks gestation: 18% vs 7%, p 0.04), but not at 3 months postpartum (20% vs 14%, p 0.55). Recruitment was suspended early by an Independent Data and Safety Monitoring Board when an int...

This study aimed at presenting a method for formulating optimal production, repair and replacement policies. The system was based on the production rate of defective parts and machine repairs and then was set up to optimize maintenance activities and related costs. The machine is either repaired or replaced. The machine is changed completely in the replacement process, but the productio...