A Bayesian Reliability Growth Model

A model is presented for the change (growth) in reliability of a system during a test program. Parameters of the model are assumed to be random variables with appropriate prior density functions. Expressions are then derived that enable estimates (in the form of expectations) and precision statements (in the form of variances) to be made of: 1) projected system reliability at time ? after the start of the test program, and 2) system reliability after the observation of failure data. Numerical examples are presented, and extension to multimode failures is indicated.     

Formal post-graduate education in automatic control in the United States

American educational institutions have developed an approach to post graduate education which is not common in the rest of the world. This paper reviews the American system of education in automatic control beyond the baccalaureate degree and discusses some of the strengths and weaknesses of this system.     

New Communication Technologies and the Information Worker: The Influence of Occupation

Attitudinal differences among professionals, managers, clerical staff, and blue-collar workers hint at emerging class and gender differences in the information society.     

Performance analysis of large systems

A hybrid analytic and experimental approach to the analysis of large systems is described. The approach is iterative under the assumption that a correct analysis will not be made first time. It is primarily aimed at the analysis of the performance effect of proposed changes prior to coding them. The requirement is for a fairly approximate analysis that is easy to make. The approach is illustrated by an experiment on a relational database system but we believe it to be applicable to many kinds of large systems. The different reasons for analysing performance of a system are discussed and then the ways of approaching the analysis, with an outline of our approach. The details of our approach are given, and illustrated by our experiment.     

Technique for the Static Fatigue Testing of Fibers

An easy-to-use, low-cost method for static fatigue testing of fibers in harsh environments was developed. Stresses greater than 550 ksi (3791 MPa) are attainable yet the specimen is insensitive to external shock. The method gave good comparative results when used to test indium-coated fused silica fibers under distilled water or 2M NaCl solution.     

Regional and temporal dimensions of metropolitan area wage structures

Principal components analysis is applied to occupational wage data for a sample of metropolitan areas. Indexes of wage levels and skilled/unskilled differentials are derived. Areas in the same region tend to have similar wage structures, which have changed little over twenty years. A simple regression model is reasonably successful in explaining interarea variation in the two dimensions.The views expressed are the author's and do not represent any official position of the Bureau of Labor Statistics.     

Zinc Iron Chromite Pigments

The system ZnO–Fe₂O₃–Cr₂O₃ is the basis of most of the brown pigments used in the whitewares industry. The ability of iron to occur on both the tetrahedral and octahedral sites of the spinel structure leads to a versatile system yielding a variety of related shades.