Tolerance limits - a review

This review covers some known results on tolerance limits for univariate distributions. Results for parametric continuous and discrete distributions as well as those based on nonparametric methods are included. Some general results, including those for certain restricted families of distributions are also covered. Sample size determination and related problems are discussed     

Life Cycle Risks for Human Health: A Comparison of Petroleum Versus Bio-Based Production of Five Bulk Organic Chemicals

This article describes the development and application of a generic approach to the comparative assessment of risks related to the production of organic chemicals by petrochemical processes versus white biotechnology. White biotechnology, also referred to as industrial biotechnology, typically uses bio-based feedstocks instead of the fossil raw materials used in the petrochemical sector. The purpose of this study was to investigate whether the production of chemicals by means of white biotechnology has lower conventional risks than their production by petrochemical processes. Conventional risks are the risks of well-established processes, and not those related to genetically modified microorganisms and plants. Our approach combines classical risk assessment methods (largely based on toxicology), as developed by the life cycle assessment (LCA) community, with statistics on technological disasters, accidents, and work-related illnesses. Moreover, it covers the total process chain for both petrochemical and bio-based products from cradle to grave. The approach was applied to five products: the plastics polytrimethylene terephthalate (PTT), polyhydroxyalkanoates (PHA), polyethylene terephthalate (PET), polyethylene (PE), and ethanol. Our results show that the conventional risks related to the white biotechnology products studied are lower than those of the petrochemical products. However, considering the uncertainties with respect to the ranges of input data, the (incomplete) coverage of emissions by the environmental priority strategies (EPS) 2000 method, and the uncertainties of the assumptions made in this study (i.e., large to very large), the differences in results between bio-based and petrochemical products fall into the uncertainty range. Because of this, future research is necessary to decrease the uncertainties before we can conclude that the conventional risks of biotechnologically produced chemicals are lower than those of fossil-fuel-derived chemicals.     

Bayesian estimation of parameters of mixed geometric failure models from Type I group censored sample

The estimation problem of the parameters of a mixed geometric lifetime model, using Bayesian approach and Type I group censored sample, will be investigated in the case of two subpopulations. The Bayes estimates are derived for squared error, minimum expected, general entropy and linex loss functions under informative and diffuse priors. A practical example given by Nelson (W.B. Nelson, Hazard plotting methods for analysis of the life data with different failure models, J. Qual. Technol. 2 (1970), pp. 126–149) is considered. A simulation study is carried out along with risk.     

A fourth order rotatable design in three dimensions

The necessary and sufficient conditions for a set of points to form a rotatable design of order four have been given by Patel and Arapkoske (1985). One such set of 104 points for three factors which satisfies these conditions is given in this paper.     

A frame of reference for strategy development

Strategy development in today's volatile business environment demands increased management concern with fundamental issues which go beyond the balance sheet and the income statement to deal with the proper positioning of the corporation and its units to achieve long-term profitable survival. This is well understood. On the other hand, it is equally clear that management capacity—in terms of man hours of talent available—is the most important resource of any corporation and is also limited. In this article the authors set out to develop a frame of reference for analysing the corporation, its individual business and its competitors. Their objective is to provide management with the tools they need to deploy their creative entrepreneurial talent more efficiently by focusing on strategically relevant issues, using guidelines based on the ever-increasing body of research available today.     

A look at an interactive classroom-based drug abuse prevention program: interactive contents and suggestions for research

Interactivity has been shown to be a critical element of effective drug abuse prevention programs. This study examined the contents of Project Towards No Drug Abuse, a program that has revealed strong effects only when delivered in a highly interactive version. Types of teacher and student interactive messages were identified. It is speculated that explicit action on the part of the teacher to have students make statements and ask questions of one another may be the essence of effective drug education program delivery. Suggestions for future research on interactivity were made.     

Technological forecasting for power generation—A study using the Delphi technique

Technological forecasting is a powerful technique for obtaining insights into possible futuristic innovations. The forecast can provide a basis for long-range planning and policy formulation in organizations. Technological forecasting, though a useful and powerful tool, has yet to be applied widely in developing countries. This paper outlines a forecasting exercise carried out by the authors using the Delphi technique in India. The focus of the exercise was on electric energy generation and transportation. The findings have been compared with other available studies in India in similar areas. The paper also illustrates how additional information inputs can mould such forecasts. For this purpose, the authors have compared the results of the current study with the results of a similar study carried out in the same organization 8 years earlier. The change in perception regarding the timing of certain items is very evident and the underlying reasons have been given.     

Board of director efficacy and firm performance variability

While academic researchers continue to debate the effect of board independence in increasing performance, its efficacy could also be reflected in whether firm performance is made more stable. Board governance activities are a constellation of actions aimed at managing agency costs and ensuring the viability of a company over time. The efficacy of such actions would, therefore, be reflected in a distal outcome, specifically, in lower firm performance variability. Boards that can control agency costs and limit both underinvestment and overinvestment would reduce a firm's deviation from its mean performance trajectory. Using a longitudinal sample of publicly traded companies in the United States, we find that board stability, board resource provision, and CEO influence are negatively associated with performance variability. Board independence is not associated with performance variability. With increasing board independence, greater board stability and greater CEO influence are negatively associated with performance variability, however, greater board resource provision is not associated with performance variability.