Improving perishable product inventory management using goal programming

The multiple objectives of perishable product inventory management are examined in this paper. These objectives include: (1) satisfying demand by carrying sufficient inventories, (2) holding down inventory carrying costs, (3) keeping the amount of product spoilage (outdating) at an acceptable level, and (4) maintaining quality by using the product while it is still fresh, and (5) keeping the cost of rotation low. Some of the above objectives are in conflict. Thus, certain redistribution policies may help attain one or more of these objectives to a greater extent. Redistribution involves the transfer of the product from outlets where demand is low to outlets where demand is high. A goal programming model for solving redistribution problems is presented. An example is provided and sensitivity analysis is performed in order to determine when redistribution is advantageous. Applicability of the model is discussed.     

Testing equality of variances in the analysis of repeated measurements

The problem of comparing the precisions of two instruments using repeated measurements can be cast as an extension of the Pitman-Morgan problem of testing equality of variances of a bivariate normal distribution. Hawkins (1981) decomposes the hypothesis of equal variances in this model into two subhypotheses for which simple tests exist. For the overall hypothesis he proposes to combine the tests of the subhypotheses using Fisher's method and empirically compares the component tests and their combination with the likelihood ratio test. In this paper an attempt is made to resolve some discrepancies and puzzling conclusions in Hawkins's study and to propose simple modifications.
The new tests are compared to the tests discussed by Hawkins and to each other both in terms of the finite sample power (estimated by Monte Carlo simulation) and theoretically in terms of asymptotic relative efficiencies.     

The transformational management of conflict: A perspective from the early Christian church

An understanding of transformational leadership has been developed for many spheres of management, but not previously for organizational conflict. This paper analyzes a successful conflict mediation attempt in the early Christian church and draws from it elements of a model of the transformational management of conflict that can be applied by managers in many contemporary work organizations. The elements include (a) reframing the conflict, (b) a focus on a shared organizational vision, (c) the placement of responsibility for dispute resolution in the hands of organizational members directly and indirectly involved in conflict, and (d) the use of communication devices consistent with the desired outcome. The paper suggests skills necessary for managers to implement the model and implications for research on it.     

Firm Growth and Survival: Does Ownership Structure Matter?

The publication of the passive learning model of Jovanovic and subsequently the active exploration model of Ericson and Pakes led to a resurgence in research on firm growth and survival. Empirical work measuring the relationship of growth and survival relative to size and age uncovered a number of strong regularities, consistent with the new theoretical models and also with a rather broad class of models of which the above represent special cases. But recent theoretical work has shown that when the learning models are applied to the special case of the labor managed firm, most of the sharp empirical predictions derived for profit maximization are rendered indeterminate. Given the impact of ownership structure on the theoretical results of the learning models, we use a dataset of French producer cooperatives to determine whether firms of different ownership structures actually have substantially different growth and survival patterns. We find that French cooperatives survive and grow in very much the same way as has been found for U.S. firms, suggesting that the empirical regularities previously uncovered hold for a much broader class of firms. We are left to conclude that the underlying empirical growth and survival relationships continue to hold for firms with sharply differing ownership structures, and the theoretical models are attempting to explain these broad-based relationships by means of overly specific modeling.     

Rising marginal cost and concavity of the production function

Suppose a production function, f, is continuous, quasi-concave and weakly monotone on the non-negative orthant of Euclidean n-space. Let c(·, ·) be the associated cost function. Then it is shown that f is concave if and only if for each w, c(w, ·) is convex.     

THE DETERMINANTS OF THE INTER-INDUSTRY PATTERN OF DIVERSIFICATION BY U.K. MANUFACTURING ENTERPRISES*

Evidence of the diversity of output of larger U.K. manufacturing enterprises’in 1958, 1963 and 1968 is provided in the Reports on the Census of Production. The Censuses show that between 1958 and 1968 diversification was a significant and general trend in manufacturing industries and an important element in the growth of firms during the period. Moreover diversification seems to be part of a longer term trend in U.K. industry and part of the typical development pattern of the large firm. A theory of the firm's diversification decision is proposed and from this theory predictions are made of the structural features both of a firm's primary industry and of outside industries which are likely to encourage diversification from the one industry to the other. The power of the model in explaining the pattern of diversification between SIC manufacturing orders in the period 1963–68 is weak, due in part to the wide variety of factors influencing diversification and to the aggregated form of the data. Nevertheless, the results show the importance of research and development effort in encouraging diversification and the stimulus to diversification given by profitability and risk in firms’primary industries and high rates of output growth in outside industries. While the findings offer no clear conclusions regarding the impact of diversification upon economic performance, the results are consistent with the propositions that (i) diversification encourages technical progress in industry and (ii) diversification increases the efficiency with which resources are allocated between industries.