Reliability: Modeling, Prediction, and Optimization

CHAPTER 1

An Overview

1.1 INTRODUCTION

The twentieth century was characterized by rapid changes in technology, with many changes occurring at an exponential rate, and this will certainly continue into the twenty-first century as well. Technology is, according to a standard dictionary definition, “the totality of the means employed to provide objects necessary for human sustenance and comfort.” A more appropriate definition for our purposes is “the totality of goods, tools, processes, methods, techniques, procedures, and services that are invented and put into some practical use.” (Bayraktar, 1990). Our interest in this book is on “objects” in the first definition and “goods” in the second. They can vary from relatively simple products, such as light bulbs, tires, toasters, or articles of clothing, to complex systems such as bridges, factories, power generating systems, or communications networks. Items such as these are engineered and manufactured to perform in some specified manner when operated under normal operating conditions.

By and large, engineered objects such as these perform satisfactorily, but occasionally they fail. A dictionary definition of failure is “falling short in something expected, attempted, or desired, or in some way deficient or lacking.” From an engineering point of view, it is useful to define failure in a broader sense. Witherell (1994) elaborates as follows: “It [failure] can be any incident or condition that causes an industrial plant, manufactured ...