Strategic planning for resources

In the field or purchasing and supply, 1973 was a year to be remembered. A world-wide boom in industrialised countries produced record prices in markets for food, raw materials and manufactured goods. Rates of inflation in the U.S.A., Western Europe and Japan began to approach South American levels. The value of the dollar, the pound and other major currencies fluctuated dramatically, and the stock market experienced falls comparable to those which occurred during the slump in the thirties. Finally, 1973 was the year of the oil embargo, when oil prices were almost doubled and oil supplies to the West were cut by 15–20%, resulting in the rationing of oil and other commodities in Western Europe.By any standards, this was a momentous year. It is conceivable that supply markets will never be quite the same again. The traditional form of multi-national business, integrated from supply to consumer markets, is fast disappearing as the companies formed in developing countries to secure the supply of oil, food and raw materials are being taken over by the host governments. Indeed it may be that after the traumatic experiences of this year, negotiations for food and key raw materials will be increasingly carried out by governments rather than by private companies.To cope with shortages and higher prices in food, fuels and essential raw materials, government bodies and public and private enterprises will have to develop new capabilities. Western governments have responded quickly by setting up Ministers and Ministries for Energy and by establishing huge budgets for research into the exploration and exploitation of alternative fuels. The large oil companies have declared that they are in the “energy business” and have bought interests in nuclear power and coal.But what does the energy and resource crisis mean for the average firm? It seems that in the 1970s we are experiencing a level of competition for supplies similar to the competition for consumer markets which first produced “Marketing” in the late fifties and early sixties.     

The consequences of early marriage on marital dissolution

Research has been consistent in documenting the direct negative effect of early marriage on marital stability, while disagreeing over the level of influence of status attainment measures on divorce. However, the discipline has failed to come to consensus on the complexity of these relationships: that early marriage may operate indirectly through mediating variables to increase the likelihood of divorce. The focus of this paper is an analysis of a path model which includes the estimated effects of antecedents of early marriage, early marriage and education on the probability of divorce. Findings using the General Social Surveys support research that suggests that early marriage is the most important variable influencing divorce. Further, little influence of the early marriage measure through education was found.     

A Note on standardized rates

The authors of this note demonstrate that it is not necessarily true that the standardized death-rate of a combined population will lie between the standardized death-rates of its two components.     

A test for crossing receiver operating characteristic (roc) curves

The receiver operating characteristic (ROC) curve gives a graphical representation of sensitivity and specificity of a prediction model when varying the decision treshold on a diagnostic criterion. A classical test for comparing the overall accuracies for two models -1 and 2- is based on the difference between ROC curves areas - related to its standard error. This test is designed for the situation where ROC curve 1 caps ROC curve 2. Often both curves cross :in this paper, a new test, based on the integrated difference between the curves, is proposed to deal with this situation. In a simulation experiment, the new test was less powerful than the old test for detecting an overall superiority, but much more powerfull against the crossing alternative.     

Calculation of the Prokhorov distance by optimal quantization and maximum flow

Calculating exact values of the Prokhorov metric for the set of probability distributions on a metric space is a challenging problem. In this paper probability distributions are approximated by finite-support distributions through optimal or quasi-optimal quantization, in such a way that exact calculation of the Prokhorov distance between a distribution and a quantizer can be performed. The exact value of the Prokhorov distance between two quantizers is obtained by solving an optimization problem through the Simplex method. This last value is used to approximate the Prokhorov distance between the two initial distributions, and the accuracy of the approximation is measured. We illustrate the method on various univariate and bivariate probability distributions. Approximation of bivariate standard normal distributions by quasi-optimal quantizers is also considered.