Pioneers of the reliability theories of the past 50 years

This paper is dedicated to all the researchers for their contributions in reliability theories in the past 50 years. The paper provides a summary on the pioneers of reliability theories, and how their works placed a great influence on our reliability analysis today. This is also a survey paper on reliability theories and methods. The information provided in this paper is mostly based on literatures found first hand to provide as much a neutral view as possible. However, some of the information is adopted from Refs. 1-4. Area of interest in the reliability analysis included representation of reliability parameters, renewal theory, coherent structure, diagram-based models, theoretical methods, and other miscellaneous techniques. Diagram based models included block diagrams, fault tree analysis (FTA), event tree analysis, and flowgraphs. Theoretical methods included queueing theory, asymptotic analysis, Boolean algebra, Bayesian method, Monte Carlo simulation, optimization techniques. Miscellaneous methods that cannot be classified in any of the categories are also provided. Looking back in the last century, a lot of the contributions to reliability research were done in the last 50 years. Weibull, Epstein and Sobel had made a significant influence on the distribution functions we used today. Lotka, Campbell, Feller, Cox, Smith, Barlow, Proschan, Hunter, Marshall, Esary, Gnedenko, Belyaev, and Solov´yev had advanced the theories for reliability. Takacs´ paper in sojourn time provided an initiative to the asymptotic studies. Birnbaum started a whole family on component importance measure for coherent structure.