Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Throughout this work, conditional failure rates for discrete positive integer-valued random variables and some of their applications are considered in some detail. Conditional failure rates are of fundamental importance in the study of lifetime distributions and many of their properties. All the notions introduced and the results derived here can be used in reliability theory, operations research, inventory theory, biometry, etc. Chapter 1 begins with the concept of conditional failure rate of a discrete random variable. Then, it is shown how to obtain explicit expressions for probability densities and survival distributions in terms of this notion. Next, extensions of the univariate results are discussed for bivariate discrete random vectors. Finally, some multivariate concepts and results are outlined. One of the fundamental applications of conditional failure rates is the mathematical representation of ageing. In Chapter 2, several univariate notions of ageing are given for discrete random variables. Such notions constitute the starting point for the classification and study of lifetime distributions that have significant importance in reliability theory, biometry, and several other areas. In Chapter 3, three important ordering relations, and a chain of implications among them, are discussed; the likelihood ratio ordering, the failure rate ordering, and the stochastic ordering. These orderings are useful in applied probability, stochastic processes, statistics, etc. In particular, they are an essential tool in the study and analysis of systems with dependent components, specially when the components are associated. No attempt is made, however, to consider specific applications of these orderings here. Finally, Chapter 4 contains an application of conditional failure rates in the analysis of repairable systems. A random mechanism of repair of failed units, called imperfect repair, is introduced and some simplified models are considered in some extent. These models can be used in the analysis and design of maintenance policies.

Pavement performance prediction in terms of fatigue cracking and surface rutting are essential for any mechanistically-based pavement design method. Traditionally, the estimation of the expected fatigue field performance has been based on the laboratory bending beam test. Full-scale Accelerated Pavement Testing (APT) is an alternative to laboratory testing leading to advances in practice and economic savings for the evaluation of new pavement configurations, stress level related factors, new materials and design improvements. This type of testing closely simulates field conditions; however, it does not capture actual performance because of the limited ability to address long-term phenomena. The same pavement structure may exhibit different response and performance under APT than when in-service. Actual field performance is better captured by experiments such as Federal Highway Administration's Long-Term Pavement Performance (LTPP) studies. Therefore, to fully utilize the benefits of APT, there is a need for a methodology to predict the long-term performance of in-service pavement structures from the results of APT tests that will account for such differences. Three models are generally suggested to account for the difference: shift factors, statistical and mechanistic approaches. A reliability based methodology for fatigue cracking prediction is proposed in this research, through which the three models suggested previously are combined into one general approach that builds on their individual strengths to overcome some of the shortcomings when the models are applied individually. The Bias Correction Factor (BCF) should account for all quantifiable differences between the fatigue life of the pavement site under APT and in-service conditions. In addition to the Bias Correction Factor, a marginal shift factor, M, should be included to account for the unquantifiable differences when predicting the in-service pavement fatigue life from APT. The Bias Correction Factor represents an improvement of the currently used "shift factors" since they are more general and based on laboratory testing or computer simulation. By applying the proposed methodology, APT performance results from a structure similar to an in-service structure can be used to perform four-point bending beam tests and structural analysis to obtain an accurate estimate of the necessary Bias Correction Factor to estimate in-service performance.

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Industrial and Systems Engineering." Includes bibliographical references (p. 171-179).

Thesis (Ph.D.)--McMaster University, 2002. / Adviser: N. Balakrishnan. Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.)--McMaster University, 2002. / Adviser: N. Balakrishnan. Includes bibliographical references. Also available via World Wide Web.

Thesis (M.S. in Management)--Naval Postgraduate School, June 1990. / Thesis Advisor(s): Boger, Dan C. Second Reader: Roberts, Benjamin J. "June 2009." Description based on title screen as viewed on October 19, 2009. DTIC Descriptor(s): Accelerated testing, cycles, emergencies, global, international, marine transportation, marketing, military reserves, patterns, procurement, requirements, ships DTIC Indicator(s): Airlift operations, Sealift operations, Military reserves, Ready reserve force, Market research, International trade, Theses. Author(s) subject terms: Sealift, used ship market. Includes bibliographical references (p. 87-89). Also available in print.

Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Begovic, Miroslav; Committee Member: Hampton, Nigel; Committee Member: Harley, Ronald; Committee Member: Michaels, Thomas; Committee Member: Vidakovic, Brani. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Lo, Kwok Yuen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 52-53). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Scope of the thesis --- p.3 / Chapter 2 --- Lifetime Model --- p.4 / Chapter 2.1 --- Introduction --- p.4 / Chapter 2.2 --- Weibull Distribution --- p.4 / Chapter 2.3 --- Step-Stress Experiment --- p.5 / Chapter 3 --- Maximum Likelihood Estimation of Model Parameters --- p.9 / Chapter 3.1 --- Introduction --- p.9 / Chapter 3.2 --- Maximum Likelihood Estimation --- p.10 / Chapter 3.3 --- Fisher Information Matrix --- p.13 / Chapter 3.4 --- Numerical Methods improving Newton's method. --- p.17 / Chapter 3.4.1 --- Initial values --- p.18 / Chapter 3.4.2 --- Fisher-Scoring method --- p.19 / Chapter 4 --- Optimal Experimental Design --- p.21 / Chapter 4.1 --- Introduction --- p.21 / Chapter 4.2 --- Optimal Criteria --- p.22 / Chapter 4.3 --- Optimal Stress-changing-time Proportion --- p.23 / Chapter 4.3.1 --- Optimal n versus the shape parameter B --- p.24 / Chapter 4.3.2 --- "Optimal n versus the parameters ao, a1" --- p.27 / Chapter 4.3.3 --- Optimal n versus the initial stress level x1 --- p.32 / Chapter 4.3.4 --- Optimal n versus the censoring time t2 --- p.33 / Chapter 4.4 --- Sensitivity Analysis --- p.34 / Chapter 4.4.1 --- Effects of the shape parameter B --- p.34 / Chapter 4.4.2 --- "Effects of the parameters ao, al" --- p.37 / Chapter 5 --- Conclusion Remarks and Further Research --- p.39 / Chapter A --- Simulation Algorithm for a Weibull Type-I Censored Simple Step-Stress Model --- p.41 / Chapter B --- Expected values of Fisher Information Matrix --- p.42 / Chapter C --- "Derivation of P(A1, A2)" --- p.50 / Bibliography --- p.52

The quantity and length of optical fibers required for the Hobby-Eberly Telescope Dark Energy eXperiment (HETDEX) create unique fiber handling challenges. More than 33,000 optical fibers will enable the Hobby-Eberly Telescope (HET) to collect data on at least one million galaxies that are 9 billion to 11 billion light-years away, yielding the largest map of the universe ever produced [1,2]. The design advantages made possible by optical fibers also forms challenges to prevent damage to the fragile fibers that can lead to Focal Ratio Degradation (FRD) [3]. Therefore, a life cycle test must be conducted to study fiber behavior and measure FRD as a function of time. This thesis describes the design and design methodology of an electro-mechanical test apparatus for accelerated life testing of optical fiber assemblies. The design methodology summarizes the development of functional requirements and constraints that drove the design. The test apparatus design utilizes six linear actuators to replicate the movement of the fiber system deployed on HETDEX for over 65,000 accelerated cycles, simulating five years of actual operation. The electro-mechanical test apparatus will provide insight into the effects of load history on the performance of optical fibers which published data has thus far been lacking. Performance of the electro-mechanical test apparatus will be demonstrated through simulation, modeling and calculations. The test results that will be generated from the accelerated life test will be of great interest to designers of robotic fiber handling systems for major telescopes. / text