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Expert has applied and developed statistical methods in an engineering and manufacturing context for most of his career. Some projects have been the analysis of survey data on bearing life, development of statistically-based life prediction theory, the development of statistically-based models for the analysis of the contact of rough surfaces, and the development of methodology for the analysis of Weibull distributed data. He has consulted with engineers with regard to the design of experiments and propagation of error problems in gaging. He teaches graduate-level courses in engineering statistics, quality control, reliability, design of experiments, response surface analysis, and regression analysis. He also has developed and delivered short courses in forecasting, reliability, and using the Weibull distribution.

Expert has engaged in a number of sponsored efforts aimed at evaluating life prediction theory for rolling bearings. The projects involved the compilation and reduction of life data, the prediction of life under a model, and comparison of predicted life to actual life.

Expert developed, and continues to develop, methodology for the analysis of life data, with primary emphasis on the Weibull distribution. This includes exact confidence intervals for Weibull parameters, analysis of sudden death tests, multiple comparisons, regression analysis with Weibull response as applied to the analysis of accelerated life tests, and the analysis of factorial experiments with Weibull response. He also teaches graduate courses in reliability theory.

Expert has experience in post-processing surface profile data for such things as peak count, zero-level crossings, and spectral content and developing models for predicting surface interaction based on microtopographic measurements. Since 1991, he has been Director of Penn State Great Valley Surface Microtopography Laboratory, which is equipped through NSF support with a state-of-the-art profile measurement device (Rank Taylor Hobson Form Talysurf). The laboratory works with industry in developing manufacturing processes which result in acceptable levels of surface microgeometry.

Expert has worked extensively in the area of tribology, which focuses on the microscale phenomena that occur at the tips of contacting surface asperities. He has developed computer models for predicting the means and probability distributions of microcontact area, load, and flash temperature, as well as the number and relative proportion of the microcontacts which undergo plastic deformation. Further work considers the effect on these variables of surface coatings, and skewness/kurtosis of the asperity height distribution.