— This paper deals with the availabiïity and reliability analysis of a 2-unit System with two service facilities-one for préventive maintenance and the other for repair. The times to failure and préventive maintenance of a unit are assumed to be arbitrariîy distributed whüe the times for repair and préventive maintenance are exponentially distributed. The Laplace transforms ofthe mean down-time...

Introduction: Social support is one of the most important indices affecting adaptation to aging process as well as the problems and complications of the aging period such as anxiety, death and social support. This study was aimed to determine the correlation of social support with death anxiety among the elderly of Tehran, Iran.   Methods: In this correlational study, 208 elderly referring to...

background: including multivariate survival data can be pointed competing risks data. there are various methods to analyze such data such as semi-parametric methods of cause-specific hazard function, and cumulative incidence function. the aim of this study was to deploy competing risks model to analyze the determinants of patients with liver cirrhosis. materials and methods: during the one-year...

during one year period from 2010 to 2011 the samples from pneumonic animals were taken and transported to the laboratory. pasteurella multocida were identified in 16.6% of animal by biochemical test. the high incidence of p. multocida was obtained in the south of fars province, where the area was warm region. the mean death time between the isolates was 12-18 and 19-24 hours. only the capsular ...

Abstract: This paper presents a mathematical model for a multi-state complex repairable manufacturing system with four types of failures such as common cause, partial, human and catastrophic incorporating waiting time to repair. As regards to repairing of the system, it has to be wait for repair due to unavailability of repair facility after common cause failure. The system may also fail due to...

Un-availability can be quantitatively defined as the ratio of MTTR (mean time to repair) to the sum of MTTR (mean time to repair) and MTTF (mean time to failure). Decreasing MTTR is as valuable as increasing MTTF. By learning why systems fail, failure distribution across parts of an IS, we attempt to envision a plausible model for future Information Technology (IT). In this endeavor, we focus o...

Designing highly dependable systems requires a good understanding of failure characteristics. Unfortunately, little raw data on failures in large IT installations is publicly available. This paper analyzes failure data recently made publicy available by one of the largest high-performance computing sites. The data has been collected over the past 9 years at Los Alamos National Laboratory and in...