Knowledge that Transforms

This paper concerns a class of network location problems with minimum or maximum separation requirements between (uncapacitated) facilities or between demand points and the facilities, or both. Its purpose is three-fold. First, it is to recognize distance constraints as increasing real life restrictions through various motivating illustrations. Using a new classification scheme, the paper introduces a variety of distance-constrained problems defined in a unified manner. These include a number of new problems. Second, it is to survey existing solution techniques, available only for a few of such constrained problems. Finally, it is to shed some light on yet unstudied problems by exploring possible extensions of some of the known solution techniques or discussing varying degrees of difficulties involved. In particular, the paper presents integer programming formulations of several new problems along with the results of applying linear programming relaxation methods. Although the computational experience is somewhat disappointing for some of these problems, the results provide greater insight into the problems. With the stated purpose, it is hoped that this paper will stimulate future research in this important problem area.

Existing innovation diffusion models assume that individual experience with the product is always communicated positively through word-of-mouth. For certain innovations, however, this assumption is tenuous since communicators of the product experience may transfer favorable, unfavorable, or indifferent messages through word-of-mouth. This paper examines a diffusion model for products in which negative information plays a dominant role, discusses its implications for optimal advertising timing policy and presents an application to forecast attendance for the movie Gandhi in the Dallas area.

Multi-item capacitated lot-sizing problems are reformulated using a class of valid inequalities, which are facets for the single-item uncapacitated problem. Computational results using this reformulation are reported, and problems with up to 20 items and 13 periods have been solved to optimality using a commercial mixed integer code. We also show how the valid inequalities can easily be generated as part of a cutting plane algorithm, and suggest a further class of inequalities that is useful for single-item capacitated problems.

The impact of a decision maker's risk aversion on the choice of an optimal sampling plan is empirically examined for various batch sizes and prior distributions of the process quality level. These plans are compared to those of the classical linear cost model. The comparisons show that substantial differences in the characteristics of an optimal sampling plan (i.e., probability of acceptance, optimal sample size and expected total cost) occur when risk aversion is considered. A discussion of the optimization characteristics involved in the selection of a sampling plan is also presented. An optimization algorithm which obtains an optimal sampling plan based on the criterion of maximizing expected utility is proposed and evaluated.

This paper extends the usual regression analysis to include the partition of the variance to examine the possible secondary and higher order impact of policy variables in a policy impact model. The federal Medicaid program is analyzed using the methodology to assess the impact of the policy variable—differential federal matching ratio—on the per capita expenditure from state and local sources. Our result shows that the policy is ineffectual on its own but modestly effective with others when all important factors are considered simultaneously.

A complete, unified description is given of the design, implementation and use of a family of very fast and efficient large-scale minimum-cost (primal simplex) network programs. The class of capacitated generalized transshipment problems solved includes the capacitated and uncapacitated generalized transportation problems and the continuous generalized assignment problem, as well as the pure network flow models which are specializations of these problems. These formulations are used for a large number of diverse applications to determine how (or at what rate) flows through the arcs of a network can minimize total shipment costs. A generalized network problem can also be viewed as a linear program with at most two nonzero entries in each column of the constraint matrix; this property is exploited in the mathematical presentation with special emphasis on data structures for basis representation, basis manipulation, and pricing mechanisms. A literature review accompanies computational testing of promising ideas, and extensive experimentation is reported which has produced GENNET, an extremely efficient family of generalized network systems.

Independence axioms similar to those proposed for multiattribute von Neumann–Morgenstern linear utility theory are examined in the context of new nonlinear utility theories developed by Chew and MacCrimmon, and Fishburn. These new theories weaken the independence axiom of von Neumann and Morgenstern, and Fishburn's theory does not require preferences to be transitive. The paper shows that axioms for independence between attributes lead to decompositions of utility for the nonlinear theories that are related to standard decompositions for linear utility.

Plywood manufacture includes two fundamental stages. The first is to peel or separate logs into veneer sheets of different thicknesses. The second is to assemble veneer sheets into finished plywood products. At the first stage a decision must be made as to the number of different veneer thicknesses to be peeled and what these thicknesses should be. At the second stage, choices must be made as to how these veneers will be assembled into final products to meet certain constraints while minimizing wood loss. These decisions present a fundamental management dilemma. Costs of peeling, drying, storage, handling, etc. can be reduced by decreasing the number of veneer thicknesses peeled. However, a reduced set of thickness options may make it infeasible to produce the variety of products demanded by the market or increase wood loss by requiring less efficient selection of thicknesses for assembly. In this paper the joint problem of veneer choice and plywood construction is formulated as a nonlinear integer programming problem. A relatively simple optimal solution procedure is developed that exploits special problem structure. This procedure is examined on data from a British Columbia plywood mill. Restricted to the existing set of veneer thicknesses and plywood designs used by that mill, the procedure generated a solution that reduced wood loss by 79 percent, thereby increasing net revenue by 6.86 percent. Additional experiments were performed that examined the consequences of changing the number of veneer thicknesses used. Extensions are discussed that permit the consideration of more than one wood species.

For decades, policy makers in both the public and private sectors have been concerned with the question: What is the impact of changes in federal R and D support on company-financed R and D expenditures? This is one of the first empirical studies at a micro level of this topic. The results, which pertain to energy R and D, indicate a complementarity between government-financed and company-financed R and D, on the average, although there is a considerable amount of interfirm variation in this regard. In about one-third of the projects studied, federally-financed R and D projects suggested some further R and D into which the firm invested its own funds. The results of a logit analysis suggest that whether or not a government-financed R and D project results in such a spinoff depends on the extent to which the performing firm contributes to the formulation of the project’s goals and strategies.

Because many organizations have not been successful in introducing new task and managerial methods into the workplace, considerable attention has been directed toward developing a more complete understanding of organizational innovation. Three separate literatures (organizational science, engineering/R&D management, and MS/OR/MIS implementation) have, in fact, been concerned with innovation and technology diffusion; however, surprisingly little integration among the three has occurred. This paper reports on a study which examined a key tenet from each of these literatures in an effort to construct a robust model of innovative behavior. Specifically, the study utilized survey data in examining the validity of “push-pull” theory (i.e., that innovation is most likely to occur when a need and a means to resolve that need are simultaneously recognized) as well as the importance of top management attitude toward an innovation and of organizational receptivity toward change. The research context involved the diffusion of six modern software practices into 47 software development groups. While the model's independent variables explained a rather large amount of the variance in the use of these modern software practices, “push-pull” theory was not validated. A number of explanations are offered for the apparent failure of “push-pull” theory. Top management attitude and organizational receptivity toward change, however, were generally found to influence organizational innovation. As hypothesized, significant differences emerged in the factors influencing administrative and technical innovations with organizational receptivity toward change important only for the technical innovations. This suggests that organizational processes facilitating innovation should vary depending on the nature of the innovation involved.