bluuebunny/crossref_metadata_2025 huggingface dataset:
A Diffusion Approximation to the Multi-Server Queue
Authors: Halachmi Baruch , Franta W. R.
Published: November 2008

Exact solutions to queueing problems with customer interarrival times and customer service times drawn from arbitrary (generalized) distributions have not been found. We are, therefore, much interested in good quality approximate solutions to such problems. This paper presents a methodology for obtaining (approximately) the distribution of the number of customers in a multiserver queue for which both the customer interarnval and customer service times are drawn from arbitrary distributions. The approximation is based on the theory of diffusion, depends only on the means and variances of the interarnval and service time distributions, and as the numeric examples attest is of very good quality when the queueing system is heavily loaded. The approximate solution is obtained via a very simple computational procedure, so that good quality approximate solutions to such problems can be easily produced.
Pay Satisfaction: An Empirical Test of a Discrepancy Model
Authors: Shapiro H. Jack , Wahba Mahmoud A.
Published: November 2008

Lawler's discrepancy model of pay satisfaction was tested to determine its viability as a predictor of pay satisfaction. An analysis of die data seems to indicate that a substantial portion of the model is not supported. Thirteen out of nineteen proposed variables tested were found to have little or no relationships with pay satisfaction. However, social comparison, wage history, status, actual pay, performance and job difficulty were found to have weak to moderately strong relationships with pay satisfaction. Implications for the design of reward systems in organizations are discussed.
Determining Reorder Points When Demand is Lumpy
Authors: Ward J. B.
Published: November 2008

Lumpy or sporadic demand patterns with highly skewed distributions are common in parts and supplies types of stockholdings, and much of available inventory control methodology is not appropriate for such items. This paper presents a simple, easily used regression model to calculate order points for lumpy items from knowledge of demand parameters and the desired service level. It is derived from the particular compound Poisson distribution commonly called “stuttering Poisson.” Results are derived and presented in the following framework, though application is not limited to these conditions. The control discipline is the order quantity, order point (Q, R) approach with continuous review. Lead time is assumed to be known and constant. An assigned service level is assumed based on fraction of demand supplied without backorder. Joint optimization of Q and R is not addressed, but rather order point is based on an independently calculated order quantity. Forecasting methods are not addressed, but the mean and variance of lead time demand forecasts are assumed available.
Teaching Dynamic Feedback Systems Thinking: An Elementary View
Authors: Roberts Nancy
Published: November 2008

A pilot study has demonstrated that dynamic feedback systems concepts can be taught to children as young as ten and eleven years old, when nurtured by a teaching strategy that follows Bruner's emphasis upon the teaching of basic structures [Bruner, J. S. 1963. The process of education. Vintage Books, New York.]. Focusing on the understanding and representation of underlying structures in the area of social studies, the author developed, implemented and evaluated a curriculum to teach children both to read dynamic feedback systems causal-loop diagrams and also to develop feedback diagrams explaining causal relationships among variables discussed in written materials. The curriculum enabled fifth and sixth grade children to learn analytic and synthesis skills previously taught primarily to graduate classes at M.I.T. The positive results achieved seem transferable to broader groups wishing to become familiar with dynamic feedback systems thinking and its applicability to social problems.
An Appraisal of the Empirical Performance of the Linear Decision Rule for Aggregate Planning
Authors: Schwarz Leroy B. , Johnson Robert E.
Published: November 2008

More than twenty years after the publication of the Linear Decision Rule (LDR) of Holt, Modigliani, Muth, and Simon (HMMS), the LDR remains an implementation failure. No company is reported to be using it. This paper hypothesizes that the reason for this failure may be a very simple one: the incremental benefit of aggregate planning (i.e., the coordinated optimization of aggregate work force, production, and inventory) over improved aggregate inventory management alone may be quite small. To demonstrate our hypothesis we reexamine the original paint company cost comparisons presented by HMMS, and show that virtually all of the LDR's reported saving over paint company management could have been obtained with a one time adjustment in management's aggregate buffer inventory level. We conclude that although the LDR might provide significantly larger savings than improved aggregate inventory management alone, published empirical results fail to demonstrate that potential. The implications of our hypothesis and conclusions are discussed.
Unnetworks, with Applications to Idle Time Scheduling
Authors: Bartholdi John J. , Ratliff H. Donald
Published: November 2008

Integer linear programs with 0-1 constraint matrices arise frequently in scheduling and staffing models. For many such problems it is natural to model processor availability by columns of the constraint matrix, where 1's indicate processor availability for production and 0's indicate idle periods. Efficiently solvable problems have generally been identified in terms of special patterns of 1's within the matrix. Exploiting the fact that idle time is the complement of production time, we identify classes of problems that are efficiently solvable because of special patterns of 0's. In particular, several interesting idle-time scheduling problems are shown to be solvable as finite and bounded series of network flow or matching problems.
Note—An Efficient Goal Programming Algorithm Using Constraint Partitioning and Variable Elimination
Authors: Arthur Jeffrey L. , Ravindran A.
Published: November 2008

An efficient algorithm for solving linear goal programming problems using partitioning and elimination procedures is presented. The algorithm takes advantage of the definition of ordinal preemptive factors in the objective function inherent in most goal programming formulations. Preliminary results indicate that the partitioning algorithm is superior to the existing methods for solving goal programming problems.
Note—An Improved Algorithm for the Stationary Cost Dynamic Lot Size Model with Backlogging
Authors: Morton Thomas E.
Published: November 2008

For the important special case that costs are linear and stationary over time, an improved algorithm is presented for the dynamic lot size model with backlogging which is comparable in difficulty to the standard no-backlogging algorithm. Planning horizon procedures analogous to those given by Lundin-Morton and Blackburn-Kunreuther are also developed. The results are also generalized to the concave cost case.
The Process and Product of System Design
Authors: Boland Richard J.
Published: November 2008

Given that user involvement is important in system design, this study addresses the as yet unexplored question of how a user should be involved in the system design process. Two radically different processes of interaction between a systems designer and a manager were compared in an information system design exercise.

In one interaction process, the designer conducted a traditional interview of the manager. He asked questions, analyzed data and made suggestions. In the alternative interaction process, there was an initial sharing of information and mutual suggestions, followed by a critique of each other's suggestions.

The study found that for this ill-structured problem: The alternative interaction process produced higher quality designs with important implementation advantages. The two interaction processes produced designs which used different types of organization control strategies. These results may be due to a problem finding contingency—different processes of interaction may help to define different problems, and thereby produce different, but equally rational, solutions.

For the management of organization design, the process of interacting with users has important implications for the quality of the resulting design, the type of organization control strategy employed, and the subsequent implementation of the system.
(s, S) Policies Under Continuous Review and Discrete Compound Poisson Demand
Authors: Archibald Blyth C. , Silver Edward A.
Published: November 2008

We consider inventory policies for a continuous review system with discrete compound Poisson demand, convex holding-penalty cost and fixed order cost. Beckmann has showri that under these conditions (s, S) policies are optimal. We develop recursive formulae to calculate the cost for any pair (s, S). Relations among s, S, S − s and the cost are produced that lead to an efficient determination of the optimal s and S. Tighter bounds are utilized than those obtained by Veinott and Wagner for the analogous case of periodic review. Sensitivity considerations are discussed.
Archetypes of Strategy Formulation
Authors: Miller Danny , Friesen Peter H.
Published: November 2008

There have been few attempts to understand the strategy making process by examining the organizational and environmental context in which it occurs. Rather than adopting the stance of contingency theorists who focus mainly on bivariate relationships, we decided to look for simultaneous associations among a fairly large number of variables. It was hoped that these variables would configure into models or archetypes which describe a series of different, though very frequently occurring modes or organizational failure and success. The methodology used to isolate archetypes is explained. Ten archetypes are described. Successful archetypes are: the adaptive firm under moderate challenge, the adaptive firm in a very challenging environment, the dominant firm, the giant under fire, the entrepreneurial conglomerate, and the innovator. Failure archetypes include: the impulsive firm, the stagnant bureaucracy, the headless giant, and the aftermath.
Patterns in Strategy Formation
Authors: Mintzberg Henry
Published: November 2008

The literature on strategy formation is in large part theoretical but not empirical, and the usual definition of “strategy” encourages the notion that strategies, as we recognize them ex post facto, are deliberate plans conceived in advance of the making of specific decisions. By defining a strategy as “a pattern in a stream of decisions,” we are able to research strategy formation in a broad descriptive context. Specifically, we can study both strategies that were intended and those that were, realized .despite intentions. A research program suggested by this definition is outlined, and two of the completed studies are then reviewed—the strategies of Volkswagenwerk from 1934 to 1974 and of the United States government in Vietnam from 1950 to 1973. Some general conclusions suggested by these studies are then presented in terms of three central themes: that strategy formation can fruitfully be viewed as the interplay between a dynamic environment and bureaucratic momentum, with leadership mediating between the two forces; that strategy formation over time appears to follow some important patterns in organizations, notably life cycles and distinct change-continuity cycles within these; and that the study of the interplay between intended and realized strategies may lead us to the heart of this, complex organizational process.
Performance and Autonomy in Organizations: Determining Dominant Environmental Components
Authors: Aharoni Yair , Maimon Zvi , Segev Eli
Published: November 2008

The formulation of a strategy for an organization begins with identifying the opportunities and risks in the environment. A full and permanent search—or scanning—of all environmental forces is both too costly and intractable in terms of management time. Our findings indicate that managers do not try to identify all environmental forces. Identifying the dominant components of the environment focuses scanning efforts and saves energy and costs.

Furthermore, our findings clearly point out that achievement of autonomy may be advanced by organizational performance. An optimal strategy for a manager seeking to increase autonomy would be to concentrate efforts on dominant environmental components. A spillover effect will generalize this autonomy.
Strategic Choice as a Negotiated Outcome
Authors: Murray Edwin A.
Published: November 2008

With increasing pressures for public accountability by private enterprise, the zone of strategic discretion for top level corporate managers is being reduced. Preliminary evidence from recent field research in a major electric utility showed that corporate plans of major strategic significance were not only “formulated” (within the company) but “negotiated” (implicitly if not explicitly) with external parties. To the extent that this phenomenon characterizes policy formation in corporations generally, conventional concepts of corporate strategy formulation as a “rational comprehensive” process are not descriptively accurate and perhaps not even as prescriptively useful as they might be.
Note—On the Maximal Covering Location Problem and the Generalized Assignment Problem
Authors: Klastorin T. D.
Published: November 2008

In many public sector location problems, it is often desirable to locate facilities in such a way to minimize the number (or cost) of facilities while insuring tint all demand centers are within a stated maximal service time front any facility. However, when insufficient resources exist to allow die construction of enough facilities to serve all demand centers within the alloted time, the location problem is frequently restated in order to locate the budgeted facilities to serve the serviced population.

Problems of the latter type are generally known as maximal covering location problems, which may have a number of extensions, including mandatory closeness constraints which place an upper bound on the maximal service time requirement for the entire population. This note demonstrates how this class of frequently encountered problems can be formulated as generalized assignment problems within the conceptual framework presented by Ross and Soland (Ross, G. T., R. Soland. 1977. Modeling facility location problems as generalized assignment problems. Management Sci. 24 (3, November) 345–357.) for other discrete public and private location problems.
Evaluating Urban Growth Policies with a Systems Simulation
Authors: Sexton Donald E.
Published: November 2008

Alternate policies for controlling the growth of a city were examined with a simulation model consisting of four sectors: national services, local services, manufacturing, and population. The policies investigated included restricting growth of manufacturing and/or government activities in the capital, moving government services from the capital, lowering the national birth rate, and making cities other than the capital more attractive places in which to live. This article describes the model construction process as well as the findings and their implications.
Integer Programming Post-Optimal Analysis with Cutting Planes
Authors: Klein Dieter , Holm Sören
Published: November 2008

Sufficient conditions have been developed for testing the optimality of solutions to all-integer and mixed-integer linear programming problems after coefficient changes in the right hand side and the objective function, or after introduction of new variables. The same conditions can be used as necessary conditions for coefficient changes to alter an optimal solution. The tests are based on cutting-plane theory, and the application of the tests requires solution of the original integer problem with a cutting-plane algorithm.
Bicriteria Transportation Problem
Authors: Aneja Y. P. , Nair K. P. K.
Published: November 2008

In a transportation problem, generally, a single criterion of minimizing the total cost is considered. But in certain practical situations two or more objectives are relevant. For example, the objectives may be minimizations of total cost, consumption of certain scarce resources such as energy, total deterioration of goods during transportation, etc. Clearly, this problem can be solved using any of the multiobjective linear programming techniques; but the computational efforts needed would be prohibitive in many cases. The computational complexity in these techniques arises from the fact that each of the methods finds the set of nondominated extreme points in the solution space where such extreme points are, generally, many. Therefore, this paper develops a method of finding the nondominated extreme points in the criteria space. Such extreme points in the criteria space would be generally less and only these are needed while choosing a nondominated solution for implementation. The method involves a parametric search in the criteria space. Although the method is developed with respect to a bicriteria transportation problem, it is applicable to any bicriteria linear program in general. The bottleneck criterion included as a third objective is particularly significant in time bound transportation schedules. A numerical example is included.
A Heuristic Lot Size Reorder Point Model for Decaying Inventories
Authors: Nahmias Steven , Wang Shan Shan
Published: November 2008

In this paper we consider the problem of finding a “good” lot size and reorder point policy for an inventory which is subject to continuous exponential decay. Examples of decaying inventories include alcohol, certain types of food items, and radioactive materials. The method of analysis is an approximate approach which parallels that of Hadley and Whitin in the no-decay case. To evaluate the effectiveness of the approximation, a computer simulation is developed to estimate and evaluate the best (Q, r) policy. A comparison of the approximate and simulated policies is made for a total of thirty test cases resulting in a maximum cost error of only 2.77%.
Channel Optimization in Complex Marketing Systems
Authors: Corstjens Marcel , Doyle Peter
Published: November 2008

Channel optimization in multiple-channel systems is a basic problem in marketing and one which has not received much attention in the literature. A model is presented which simultaneously solves three distribution decisions—the manufacturer's choice of channels (channel strategy), the number of outlets to operate within each channel (channel intensity), and the pricing structure between channels (channel management). The general form of this model is not solvable by conventional programming techniques because it is intrinsically nonconvex. The paper shows how signomial geometric programming can provide a theoretically attractive and practical solution procedure. The model is estimated and solved on a real-life case study and the important managerial and theoretical implications are discussed.
Note—A Critical Note on a Result by Lemoine
Authors: Mitrani I.
Published: November 2008

In a recent paper [Lemoine, A. J. 1977. Networks of queues—a survey of equilibrium analysis. Management Sci. 24 (4) 464–481.], A. J. Lemoine has derived an expression for the Laplace transform of the residence time T of a customer in a feed-forward exponential network. That expression was used to obtain the first two moments of T and the results agreed with those obtained earlier by Reich for the special case of single-server queues in tandem.
Note—Some Results on Sojourn Times in Acyclic Jackson Networks
Authors: Simon B. , Foley R. D.
Published: November 2008

Lemoine (Lemoine, A. 1977. Networks of queues—a survey of equilibrium analysis. Management Sci. 24 464–481.) studies sojourn times in acyclic, Jackson networks as part of his survey of equilibrium results. In his paper, he argues that a particular customer has a sojourn time at node i that is independent of his remaining sojourn time in the network given that the customer transfer from node i to node j. This assumption is then used to derive a set of equations involving the Laplace-Stieltjes transform of the sojourn times at each node from which several properties of sojourn times are determined.

In a private communication, Mitrani (Mitrani, I. 1978. A critical note on a result of Lemoine. Private communication.) argues that the independence assumption is in error and provides a heuristic argument based on a four node, acyclic, Jackson network. From this, Mitrani concludes that the sojourn time in such networks is still an unsolved problem. We make Mitrani's argument rigorous, using some new results on sojourn times in Jackson networks.
Note—A Delegation Process for Combining Individual Utility Functions
Authors: Bodily Samuel E.
Published: November 2008

A delegation process is proposed for setting the weights when a weighted sum of individual utility functions is used to make group decisions. Conditions under which a unique set of weights exist and methods for calculating these weights are obtained using the theory of Markov chains. It is shown that the Pareto optimal set at each step of delegation is a subset of the Pareto optimal set at the previous step.
Probability Models in Medicine and Biology: Avenues for Their Validation for Humans in Real Life
Authors: Neyman Jerzy
Published: November 2008

This paper represents the text of a lecture invited by The Institute of Management Sciences (TIMS). In nontechnical terms it explains certain pitfalls involved in real life public health studies concerned with exposures to low-level irradiation. Two particular recently-announced studies are discussed. The first of them is the study of health effects, particularly cancer, connected with radiation from uranium mill tailings. It is connected with the enactment in November 1978 of Public Law 95-604. The second study was announced last May. It is connected with the accident at the Three Mile Island A-plant. While both studies are irradiation oriented, the validity of their conclusions requires taking into account the exposure to noxious chemical pollutants.
An Exact Hierarchical Algorithm for Determining Aggregate Statistics from Individual Choice Data
Authors: Gensch Dennis H. , Svestka Joseph A.
Published: November 2008

A review of the literature from many disciplines reveals conceptual agreement that individuals choose among alternatives by comparing the attributes of the alternatives in a sequential process. Yet in almost all the published empirical work the model used is a simultaneous compensatory model such as regression, logit, or probit. The sequential choice modeling approach has been severely retarded by the lack of an algorithm to generate the sample statistics projectable to hold-out samples and populations. This paper attempts to fill this void by presenting a prototype aggregate hierarchical model, called HIARC, for analyzing individual choice decisions.

HIARC can be viewed as a semi-order lexicographic model that empirically estimates a set of tolerances directly from the data. HIARC and logit are applied to the same empirical data set. While the predictive accuracy is about equal, the two approaches yield different types of diagnostic information and the set of individuals whose choice is correctly predicted by one method is substantially different from the set correctly predicted by the other method.
The Cost of Decent Subsistence
Authors: Balintfy Joseph L.
Published: November 2008

Food preference and utility measures are functionally related to the frequency and quantity of foods consumed within fixed time periods. The coefficients of these functions can be estimated by psychometric or econometric methods. Total preference or utility can be maximized subject to budgetary and dietary constraints by nonlinear programming techniques. Postoptimal analysis provides the marginal utility of calories maintained in the diet at any level of the budget. The food budget where the marginal utility of calories becomes zero is defined as the Cost of Decent Subsistence (COS). It is a unique measure that embodies all the relevant factors of human food consumption such as food likes and dislikes, food prices and nutrition in a single numerical value. Computational examples with USDA food group data are presented for two time periods a decade apart. Approximations of the CDS estimates show a marked sensitivity to nutritional needs and an increase in cost over time that slightly exceeds the change of the food price index. The applicability of the the CDS concept to income maintenance policies and volume feeding programs are discussed.
Airline Safety: Some Empirical Findings
Authors: Barnett Arnold , Abraham Michael , Schimmel Victor
Published: November 2008

We consider the fatal accident records of 58 major world airlines, and in particular try to compare appropriately the safety records of airlines whose route structures overlap and which thus compete for passengers. We separately review data about the 18 principal U.S. domestic airlines and 40 major international flag carriers. A good part of effort involves trying to develop sensible measures of safety performance, and considering differences between airlines that might make misleading the direct comparison of their accident rates.

Our analysis leads us to conclude that: As a group, the U.S. domestic carriers have achieved a safety record that is excellent in both absolute and relative terms. There is no real basis for identifying any of them as especially safe or especially dangerous, for the disparities in their observed accident records are smaller than would be expected from chance fluctuations alone. Among international airlines, however, divergences in safety records arise that are both substantial and statistically significant. Generally speaking, large airlines from “Westernized” countries seem demonstrably safer than those from most countries in Latin America, Eastern Europe, and the Middle East. In all segments of the airline industry, fatality rates have dropped over 50% in the last 15 years.
A Capacitated Bottleneck Facility Location Problem
Authors: Dearing P. M. , Newruck F. C.
Published: November 2008

This paper considers the problem of locating capacitated facilities to meet customer demands. The objective of the problem considers both a bottleneck transportation cost and a total cost of opening facilities. The structure of the problem is similar to that of the total cost capacitated facility location problem. Problems with a bottleneck objective function are solved via a Lagrangean relaxation.

An implicit enumeration algorithm is developed to solve the relaxed problem. After a feasible facility configuration is selected, the resulting allocation problem is a bottleneck transportation problem. Special attention is given to the dual of the bottleneck transportation problem to aid the branching and fathoming steps of the solution procedure. Computation results are presented for several test problems.
Must—A Multiple Solutions Technique for Balancing Single Model Assembly Lines
Authors: Dar-El E. M. , Rubinovitch Y.
Published: November 2008

Research on single-model assembly line balancing has produced several good algorithms for solving large problems. All these algorithms, however, generate just one solution to the balancing problem. With these, line designers wishing to investigate alternative station combinations of work elements are forced to do so manually. This paper concerns an algorithm (MUST) which generates alternative solutions of equal quality for single-model assembly line balancing problems. The method is based on the Mansoor-Yadin algorithm and in its optimum seeking form, MUST generates all existing optimal balances in a single pass. Three heuristics, used singularly or together, are introduced for solving the larger balancing problems. These are designed to produce about 100 different balance solutions of equal quality at each pass. MUST has been successfully used in balancing assembly lines having up to 140 work elements with widely differing precedence structures. A comparison of this method with MALB, one of the most efficient known heuristic methods, results in MUST dominating or equalling MALB in every case. Reasonable computation times (average 125.4 sec.—IBM 370/168) and core usage are achieved through the use of advanced computation methods.

The need to explore alternative station combinations may arise in several ways—for example, the line designer may prefer (but not require) that certain work elements be allocated to a common station either because of: access to materials handling and storage facilities, service availability (e.g., compressed air lines), use of common tools or operator skills, etc. Alternatively, minor adjustments to the line may be required between adjacent stations in order to alleviate conditions at one station which exhibits excessive variability in its performance times. The generation of multiple solutions of equal efficiency adds a new dimension to the quality of balancing effectiveness, enabling the line designer to select the alternative that best suits his requirements.
Crew Planning at Flying Tiger: A Successful Application of Integer Programming
Authors: Marsten Roy E. , Muller Michael R. , Killion Christine L.
Published: November 2008

This paper presents a successful application of integer programming to the scheduling of flight crews for a cargo airline. The crew planning process is discussed, the role of the set partitioning model is explained, and representative computational experience is reported. The success of this application is shown to rest upon improved problem conceptualization and decomposition rather than on any advances in solution techniques.
Controlled Experimental Design for Statistical Comparison of Integer Programming Algorithms
Authors: Lin Benjamin W. , Rardin Ronald L.
Published: November 2008

Testing and comparison of integer programming algorithms is an integral part of the algorithm development process. When test problems are randomly generated, the techniques of statistical experimental design can provide a basis around which to structure computational experiments. This paper formulates the problem of constructing and analyzing controlled integer programming tests in the experimental design context and develops approaches to dealing with a number of issues that arise. Both analytic results and empirical evidence from a large experiment are employed in deriving the suggested techniques.
An Example of a Multi-Object Auction Game
Authors: Engelbrecht-Wiggans Richard , Weber Robert J.
Published: November 2008

Concurrent auctions of several objects are traditionally analyzed as if they were independent single-object auctions. Such an approximation may be very crude if bidders have budgetary restrictions, capacity constraints, or, in general, have non-linear utility functions. This paper presents a very simple multi-object auction for which explicit equilibrium strategies can be calculated; these equilibrium strategies have several qualitative characteristics arising from the multi-object nature of the example and therefore not present in typical single-object auctions. In particular, these results suggest that the observed variance in bids for offshore oil leases is not solely due to bidder uncertainty, but also to the method of auction currently employed.
Planning Horizon Procedures for Machine Replacement Models
Authors: Sethi Suresh , Chand Suresh
Published: November 2008

This paper develops efficient forward algorithms and planning horizon results for several machine replacement models under an improving technological environment over time. The models are that of cost minimization, profit maximization, and cost minimization with probabilistic breakdowns. The conditions of the improving technological environment are stated in terms of operating costs, incremental profits, and expected operating costs, respectively, for these models. The state of technology can be assumed to improve every period or every so many periods. The conditions are fairly general and are likely to be satisfied by most improving technologies.

What is shown, specifically, is that there exists a forecast horizon T such mat the optimal replacement decision for the first machine (new or existing) based on the forecast of machine technology until period T remains optimal for any longer (than T) horizon, and for that matter, the infinite horizon problem. In particular, it is possible to decide whether it is optimal to replace an existing machine at the beginning of a period or keep it at least one more period with much less information than the entire future forecast of technology. It should be noted that the forecasts become less precise farther into the future and that requiring an infinite horizon forecast for decision-making would be unrealistic. Because the planning horizon results obtained in this paper free the solution from an arbitrary horizon and ascertain the optimality of the first period decision or the first few periods decisions based on the forecast of technology only up to some finite period T, these results represent a major advance in the machine replacement literature.

These planning horizon results also enable us to develop a computationally highly efficient forward algorithm for the models under consideration. The algorithm is illustrated with a numerical example. Another important corollary of the planning horizon results is that the optimal number of machine replacements cannot decrease as the length of the horizon (planning period) increases. Planning horizon procedures are shown to be easily extendable to the existing machine case as well as the case when machine lives are constrained within a prespecified finite interval. The paper concludes with various suggestions for future research efforts.
The Reversibility Property of Production Lines
Authors: Muth Eginhard J.
Published: November 2008

A production line is treated as a series arrangement of k work stations. An unlimited supply of raw production items is available at the first station, and each item passes through all of die stations in sequence. The service time for a single item at station j is assumed to be a random variable with a probability distribution peculiar to that station. In this mode of operation any station will at any time be either busy, or idle, or blocked. A measure of the productivity of such a line is its mean production rate r. It has been conjectured that the production rate remains invariant under reversal of the production line. Line reversal means that every item passes through the stations in the reverse order, that is, beginning with station k and ending with station 1. A general proof of the reversibility property is given. First it is shown that with predetermined service times the total time required to process n dissimilar items through k dissimilar stations does not change when the order of the stations and the order of the items is reversed. Then it is shown for the stochastic case that the order of the items does not affect the production rate.
A Theory of Academic Interdisciplinary Research Performance: A Contingency and Path Analysis Approach
Authors: Birnbaum Philip H.
Published: November 2008

A theoretical model of interdisciplinary research project performance is formulated using the contingency and single-stage multivariate path analysis approaches. The model is developed using sequences of variables identified as belonging to various organizational subsystems. The model explains performance as due to problem complexity and whether the research is basic or applied. These variables are in turn moderated by the group's perceived sense of urgency, the task orientation of the project manager, the extent to which disagreements are openly discussed, and the length of time the group remains together. The manager's role was found to be crucial in project success through his/her diagnosis of the conditions calling for task oriented behaviors. The findings presented here also indicate a major difference between industrial enterprises and research projects in the sequence with which managers respond to environmental changes.
Note—Competitive Bidding with Asymmetric Information Reanalyzed
Authors: Weverbergh M.
Published: November 2008

This note reanalyzes the following problem, formerly treated by Wilson (Wilson, R. B. 1967. Competitive bidding with asymmetric information. Management Sci. 13 (July) 816–820): two parties have to submit bids for an object One of them knows the value with certainty, the other does not. The equilibrium derived differs from Wilson's solution and yields a simple explanation for the case cited by Wilson: the value of the game is essentially zero for the party with incomplete information.
Learning Curves, Production Rate, and Program Costs
Authors: Womer Norman Keith
Published: November 2008

This paper deals with a model of the firm engaged in production to order. Models of this situation frequently conclude that the size of the order and production rate each influence the costs of production. Despite this fact, empirical work on production costs focus almost exclusively on either production rate or the size of the order as explainers of variations in costs. In this paper, a model is developed which is consistent with both these facts. The model permits production rate to be a decision variable in the manufacturer's production planning. The model is solved for an optimal production plan which requires production rate to change throughout the life of the program. The planning situation, where alternative order sizes are considered, is then contrasted with the production situation, where unit costs are related to cumulative output given a production plan. This approach provides guidance for the use of data on past programs in the estimation of cost functions and the evaluation of future production plans.
An Analytic Framework for Evaluating Rolling Schedules
Authors: Baker Kenneth R. , Peterson David W.
Published: November 2008

A rolling schedule is formed by solving a multi-period problem and implementing only the first period's decisions; one period later the multi-period model is updated and the process repeated. In this paper, we provide a general framework for analyzing rolling schedules, and we examine analytically a fundamental quadratic-cost model for the effects of such factors as the length of the planning interval, the uncertainty in forecasts, and the periodicity of demand. For the quadratic model our main result is that cost performance improves monotonically as the planning horizon is lengthened. We also find that the use of terminal conditions in the multi-period model can dramatically improve rolling schedule performance.
A Simulation Study of Predictable Due-Dates
Authors: Weeks James K.
Published: November 2008

This paper describes a simulation study of assigning attainable or predictable due-dates in hypothetical labor and machine constrained job shop settings of varying size and structure. Several predictable due-date assignment rules are developed based on conditional estimates of individual job flow time derived from initial simulation runs. Mean lateness, mean earliness and mean missed due-dates are used as measures of shop performance to compare the various predictable due-date rules under conditions of varying dispatching rules and shop size and structure.

Results indicate that due-dates assigned based on expected job flow time and shop congestion information may provide more attainable due-dates than rules based solely upon job characteristics. In addition, better due-date performance appears to be achieved when due-date oriented dispatching rules are employed and when the shop system is not structurally complex.
The Cut Search Algorithm with Arc Capacities and Lower Bounds
Authors: Phillips Steve , Dessouky Mohamed I.
Published: November 2008

This paper presents a computational procedure for solving maximal flow problems in flow networks subject to positive upper bound or capacity constraints and lower bound restrictions that are equal to or greater than zero. This procedure, referred to as the cut search algorithm, locates directly the minimal cut in a flow network structure. The algorithm not only has demonstrated computational efficiency over the existing out-of-kilter procedure, but also it provides a direct solution routine for project time/cost tradeoff problems and other network cut based problem situations in which the restricting arcs of the network formulation must be located.
The Use of Optimization Models in Public-Sector Planning
Authors: Brill E. Downey
Published: November 2008

When applied to public-sector planning, traditional least-cost optimization models and their offspring, contemporary multiobjective models, have often been developed under the optimistic philosophy of obtaining “the answer.” Frequently, such models are not very useful because there is a multitude of local optima, which result from wavy indifference functions, and because important planning elements are not captured in the formulations. Omitted elements, in fact, may imply that an optimal planning solution lies within the inferior region of a multiobjective analysis instead of along the noninferior frontier. The role of optimization methods should be re-thought in full recognition of these limitations and of the relevant planning process. They should be used to generate planning alternatives and to facilitate their evaluation and elaboration; they should also be used to provide insights and serve as catalysts for human creativity. As illustrated by recent examples, these roles may require the use of several models as well as new types of optimization formulations and modified algorithms and computer codes.
Does Lag Structure Really Matter in Optimizing Advertising Expenditures?
Authors: Bultez Alain V. , Naert Philippe A.
Published: November 2008

In this article, we examine whether a better econometric specification of the sales-advertising relationship leads to significantly improved decisions. Extending the pioneering work of Nerlove and Arrow, we analyze the sensitivity of the discounted profit flow to the dynamics of advertising. On the basis of a generalized variant of their constant-elasticity model, we compare various lag structures, and derive the corresponding decision rules to determine the optimal advertising budget.

Financial consequences of misspecifications of the distributed-lag function are then evaluated. Our investigation is empirically illustrated on the basis of the data which served Palda for his demonstration of advertising cumulative effects.
Turnpike Results for Single Location Capacity Expansion
Authors: Smith Robert L.
Published: November 2008

We consider the problem of selecting capacity additions from a finite set of possible facility sizes to meet demand at a single location over an infinite horizon. The problem is motivated and illustrated by an application to the planning for the deployment of long haul transmission facilities in the nationwide intercity telephone network. Under the assumption that demand grows at an increasing rate, taken to be exponential for purposes of exposition, we prove a “turnpike theorem” which characterizes the optimal policy as one in which the least average cost facility is eventually the only optimal facility type installed over the infinite horizon. This structural result, together with an efficient algorithm for solving the finite horizon problem, which has been implemented in a facilities network planning tool known as OFNPS, leads to a constructive algorithm for finding the optimal first facility for the infinite horizon problem. The approach avoids the end of study effects inherent in a finite horizon approach to the problem.
Note—Effects of Centralization on Expected Costs in a Multi-Location Newsboy Problem
Authors: Eppen Gary D.
Published: November 2008

This paper concerns a multilocation newsboy problem with normal demand at each location and identical linear holding and penalty cost functions at each location. Consolidation of demand from several facilities is considered, and an expression is derived for the resulting expected holding and penalty costs as a function of the demand parameters for each location (means, variances, and correlation coefficients). The expression is used to demonstrate that (i) the expected holding and penalty costs in a decentralized system exceed those in a centralized system; (ii) the magnitude of the saving depends on the correlation of demands; and (iii) if demands are identical and uncorrelated, the costs increase as the square root of the number of consolidated demands.
A Closure Approximation for the Nonstationary M/M/s Queue
Authors: Rothkopf Michael H. , Oren Shmuel S.
Published: November 2008

Typical queues do not have constant arrival rates. This paper discusses effective computational methods for dealing with queues having nonstationary arrival processes. It presents a computationally undemanding approximate method for finding the time dependent mean and standard deviation of the number of customers in an s server queueing system with time-varying arrival and service rates. Results are exhibited for various 1 and 3 server queues with constant service rates and sinusoidal components in the arrival rate.
Optimal Pilfering Policies for Dynamic Continuous Thieves
Authors: Sethi Suresh P.
Published: November 2008

This paper considers the problems of a dynamic continuous thief, such as a habitual shoplifter or a gas siphoner, who must choose the pilfering rate (which increases the probability of his arrest over time) to maximize the present value of his total expected gain over a given finite or infinte horizon. The gain function incorporates the amount of pilfering, the one-shot penalty at the time of arrest and the continuous punishment subsequent to arrest. A thief is classified as a profit-maximizer, a kleptomaniac, or a risk-averter depending on whether he considers his gain function to be linear, convex, or concave in the pilfering rate, respectively. Optimal pilfering rates are obtained for each of these different types of thieves by using the methods of optimal control.

It is shown that the optimal pilfering policy of a profit-maximizing thief is bang-bang, i.e., either to pilfer at the maximum possible rate or not to pilfer at all. In the particular case of a finitely-lived profit-maximizing thief, the optimal policy is not to pilfer while the thief is young and then to pilfer at the maximum rate toward the end of his life so that the continuous punishment subsequent to his arrest will not last too long. In the infinite horizon cases, both the profit-maximizing thieves and kleptomaniacs will either never pilfer or pilfer at the maximum rate depending on whether the parameters of the problem they are facing are unfavorable or favorable. The risk-averse thief, on the other hand, would settle at an intermediate pilfering rate throughout the infinite horizon.

Finally, it is expected that knowledge of these optimal policies will have implications for the allocation of money between police, courts and penal institutions.