Availability Taken from Fall 2005 Newsletter
Abstract: Availability is the probability the system is up, available for use, at a given time. This paper explores the meaning and implications of statistical methods used for measuring and assessing system availability. The paper focuses on maintained systems that can be repaired and put back into operation. The paper examines two cases. First, it presents an overview and gives numerical examples of the statistical treatment of the availability of a simple, repairable system in discrete times. Then, it considers the case of a simple, repairable, parallel redundant system. It compares two different statistical modeling and analysis approaches. It illustrates these approaches by developing more numerical examples, performing systems analyses, and comparing their results. Finally, the paper mentions several ways to improve system availability and provides additional bibliography for further study of these topics.
Keywords: Availability - Uniform distribution - Exponential distribution - Beta distribution - Joint density function - Markov Chain - Geometric Distribution - Transition probability - State diagram matrix