bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling and Solving the Crew Rostering Problem
Authors: Caprara Alberto , Toth Paolo , Vigo Daniele , Fischetti Matteo
Published: November 2008

The Crew Rostering Problem (CRP) aims at determining an optimal sequencing of a given set of duties into rosters satisfying operational constraints deriving from union contract and company regulations. Previous work on CRP addresses mainly urban mass-transit systems, in which the minimum number of crews to perform the duties can easily be determined, and the objective is to evenly distribute the workload among the crews. In typical railway applications, however, the roster construction has to take into account more involved sequencing rules, and the main objective is the minimization of the number of crews needed to perform the duties. In this paper we propose a basic model for CRP, and describe a Lagrangian lower bound based on the solution of an assignment problem on a suitably defined graph. The information obtained through the lower bound computation is used to drive an effective algorithm for finding a tight approximate solution to the problem. Computational results for real-world instances from railway applications involving up to 1,000 duties are presented, showing that the proposed approach yields, within short computing time, lower and upper bound values that are typically very close. The code based on the approach we propose won the FARO competition organized by the Italian railway company, Ferrovie dello Stato SpA, in 1995.
Determining Production Schedules Under Base-Stock Policies in Single Facility Multi-Item Production Systems
Authors: Federgruen Awi , Katalan Ziv
Published: November 2008

In this paper we address periodic base-stock policies for stochastic economic lot scheduling problems. These represent manufacturing settings in which multiple items compete for the availability of a common capacity source, in the presence of setup times and/or costs, incurred when switching between items, and in the presence of uncertainty regarding demand patterns, production, and setup times. Under periodic base-stock policies, items are produced according to a given periodic item-sequence. This paper derives effective heuristics for the design of a periodic item-sequence minimizing system-wide costs. This sequence is constructed based on desirable production frequencies for the items, obtained as the solution of lower bound mathematical programs. An extensive numerical study gauges the quality of the proposed heuristics.
On Quasi-Reversibility and Local Balance: An Alternative Derivation of the Product-Form Results
Authors: Chao Xiuli , Miyazawa Masakiyo
Published: November 2008

We are concerned with a queueing network, described by a continuous-time Markov chain, in which each node is quasi-reversible. A new class of local balance equations is derived for the Markov chain with respect to a product-form distribution, which simultaneously provides an alternative and short proof for product form results of queueing networks with customers and signals. Furthermore, if each node is internally balanced, i.e., the total arrival rate equals the total departure rate for each node, the Markov chain is locally balanced in the ordinary sense. Our arguments reveal a close relationship between quasi-reversibility and local balance, and provide further insights into how transition rates are balanced in product form queueing networks.
How Larger Demand Variability May Lead to Lower Costs in the Newsvendor Problem
Authors: Ridder Ad , van der Laan Erwin , Salomon Marc
Published: November 2008

In this paper we consider the Newsvendor Problem. Intuition may lead to the hypothesis that in this stochastic inventory problem a higher demand variability results in larger variances and in higher costs. In a recent paper, Song (1994a) has proved that the intuition is correct for many demand distributions that are commonly used in practice, such as for the normal distribution function. However, this paper shows that there exist demand distributions for which the intuition is misleading, i.e., for which larger variances occur in combination with lower costs. To characterize these demand distributions we use stochastic dominance relations.
The Founding of INFORMS: A Decision Analysis Perspective
Authors: Keller L. Robin , Kirkwood Craig W.
Published: November 2008

We provide a decision analysis perspective on the decision making process leading to the merger of The Institute of Management Sciences (TIMS) and the Operations Research Society of America (ORSA) to form the Institute for Operations Research and the Management Sciences (INFORMS). Throughout the merger negotiation era from 1989 until the merger in 1995, discussion regarding a possible merger was framed in an objectives-oriented manner characteristic of decision analysis methods. In addition, as ORSA and TIMS officers, we applied multiobjective decision analysis and financial analysis methods in portions of the planning and negotiation process leading to the formation of INFORMS. The merger process serves as an instructive case study of the uses and limitations of formal decision analysis methods in strategy formulation and implementation.
Design of an Automated Shop Floor Material Handling System with Inventory Considerations
Authors: Johnson M. Eric , Brandeau Margaret L.
Published: November 2008

Material handling systems are almost always intertwined with the production system they serve, but problems at this interface are rarely considered together. This paper develops a model that explicitly considers the costs of material handling and inventory to simultaneously design a material handling system and set shop floor inventory policy. The research was inspired by material handling problems we observed at computer manufacturing companies such as Apple Computer and Hewlett Packard Company. Shop floor inventory policies are often a result of trial and error or simple usage calculations—and material handling system design is usually addressed given an existing inventory policy. However, a tradeoff exists between shop floor inventory policy (reorder quantities and safety stock amounts) and demands for material handling. Inventory decisions can have a particularly large impact on cost when an automated material handling system, such as an automated guided vehicle system, is used to deliver materials. This paper develops a material handling/inventory system design model that is a nonlinear mixed integer program with nonlinear constraints, and presents a solution approach based on decomposition. Computational results show that simultaneous consideration of inventory policy and material handling system design can lead to significant reductions in overall production cost.
Finding Disjoint Routes in Telecommunications Networks with Two Technologies
Authors: de Jongh Anne , Gendreau Michel , Labbé Martine
Published: November 2008

We consider networks in which a cost is associated with each arc or edge and a transition cost is associated with each node. This last cost is related to the presence of two technologies on the network and is incurred only when a flow enters and leaves the corresponding node on arcs of different types. The problem we consider consists in finding two node disjoint paths with minimum total cost. We show that it is strongly NP-complete. Then we propose two heuristics, study their worst case behavior, provide a lower bounding procedure based on Lagrangean relaxation, and finally embed those elements in a branch and bound procedure.
Pricing and the Newsvendor Problem: A Review with Extensions
Authors: Petruzzi Nicholas C. , Dada Maqbool
Published: November 2008

In the newsvendor problem, a decision maker facing random demand for a perishable product decides how much of it to stock for a single selling period. This simple problem with its intuitively appealing solution is a crucial building block of stochastic inventory theory, which comprises a vast literature focusing on operational efficiency. Typically in this literature, market parameters such as demand and selling price are exogenous. However, incorporating these factors into the model can provide an excellent vehicle for examining how operational problems interact with marketing issues to influence decision making at the firm level. In this paper we examine an extension of the newsvendor problem in which stocking quantity and selling price are set simultaneously. We provide a comprehensive review that synthesizes existing results for the single period problem and develop additional results to enrich the existing knowledge base. We also review and develop insight into a dynamic inventory extension of this problem, and motivate the applicability of such models.
Solving Inverse Spanning Tree Problems Through Network Flow Techniques
Authors: Sokkalingam P. T. , Ahuja Ravindra K. , Orlin James B.
Published: November 2008

Given a solution x* and an a priori estimated cost vector c, the inverse optimization problem is to identify another cost vector d so that x* is optimal with respect to the cost vector d and its deviation from c is minimum. In this paper, we consider the inverse spanning tree problem on an undirected graph G = (N, A) with n nodes and m arcs, and where the deviation between c and d is defined by the rectilinear distance between the two vectors, that is, L1 norm. We show that the inverse spanning tree problem can be formulated as the dual of an assignment problem on a bipartite network G0 = (N0, A0) with N0 = N1 ∪ N2 and A0 ⊆ N1 × N2. The bipartite network satisfies the property that |N1| = (n − 1), |N2| = (m − n + 1), and |A0| = O(nm). In general, |N1| ≪ |N2|. Using this special structure of the assignment problem, we develop a specific implementation of the successive shortest path algorithm that runs in O(n3) time. We also consider the weighted version of the inverse spanning tree problem in which the objective function is to minimize the sum of the weighted deviations of arcs. The weighted inverse spanning tree can be formulated as the dual of the transportation problem. Using a cost scaling algorithm, this transportation problem can be solved in O(n2m log(nC)) time, where C denotes the largest arc cost in the data. Finally, we consider a minimax version of the inverse spanning tree problem and show that it can be solved in O(n2) time.
The Importance of Power-Tail Distributions for Modeling Queueing Systems
Authors: Greiner Michael , Jobmann Manfred , Lipsky Lester
Published: November 2008

Power-tail distributions are those for which the reliability function is of the form x−α for large x. Although they look well behaved, they have the singular property that E(Xℓ) = ∞ for all ℓ ≥ α. Thus it is possible to have a distribution with an infinite variance, or even an infinite mean. As pathological as these distributions seem to be, they occur everywhere in nature, from the CPU time used by jobs on main-frame computers to sizes of files stored on discs, earthquakes, or even health insurance claims. Recently, traffic on the “electronic super highway” was revealed to be of this type, too.

In this paper we first describe these distributions in detail and show their suitability to model self-similar behavior, e.g., of the traffic stated above. Then we show how these distributions can occur in computer system environments and develop a so-called truncated analytical model that in the limit is power-tail. We study and compare the effects on system performance of a GI/M/1 model both for the truncated and the limit case, and demonstrate the usefulness of these approaches particularly for Markov modeling with LAQT (Linear Algebraic Approach to Queueing Theory, Lipsky 1992) techniques.
A Punt Returner Location Problem
Authors: Brimberg Jack , Hurley W. J. , Johnson R. E.
Published: November 2008

We formulate and solve a location problem that determines where to position punt returners to maximize the number of punts caught. The problem is unusual within the location literature because it includes the dimension of time as well as Euclidean distance. The parameters of the model are estimated from actual punt return data. Our major finding is that the standard horizontal configuration of two punt returners results in only a small increase in the percentage of punts fielded over the case where a single returner is used. Moreover if a punter is not “directionalizing,” the vertical configuration of two returners (the punter and two returners are colinear) outperforms a horizontal configuration.
Approximation Algorithms to Solve Real-Life Multicriteria Cutting Stock Problems
Authors: Chu Chengbin , Antonio Julien
Published: November 2008

This paper addresses a real-life unidimensional cutting stock problem. The objective is not only to minimize trim loss, as in traditional cutting stock problems, but also to minimize cutting time. A variety of technical constraints are taken into account. These constraints often arise in the iron and steel cutting industry. Since cutting stock problems are well known to be NP-hard, it is prohibitive to obtain optimal solutions. We develop approximation algorithms for different purposes: quick response algorithms for individual customer requirement planning to build a quotation, and elaborate algorithms to provide a production plan for the next day. These latter algorithms are submitted to less strict computation time limitations. Computational results show that our algorithms improve by 8% the performance of our partner company where the cutting plan had been carried out manually by very experienced people. Numerical comparison for small sized problems shows that these algorithms provide solutions very close to optimal. These algorithms have been implemented in the company.
Optimal Variance Structures and Performance Improvement of Synchronous Assembly Lines
Authors: Erlebacher Steven J. , Singh Medini R.
Published: November 2008

Contemporary management theories such as Just-in-Time and Total Quality Management emphasize variance reduction as a critical step in improving system performance. But little is said about how such efforts should be directed. Suppose a manager has only limited resources for variance reduction efforts. How should she allocate them among a set of competing activities? Which activity should receive the highest priority? We explore such questions in the context of a synchronous assembly line where processing times are variable, incomplete jobs are reworked at the end of the line, and the objective is to minimize the total expected work overload. Our results indicate that the station with the highest variance may not always be the best choice for variance reduction. Identifying the set of stations that should receive variance reduction in an optimal solution is not trivial. Moreover, the variances at these stations may not be reduced by the same amount or to the same level. We establish that the remaining variances among stations that receive variance reduction must conform to one of two preferred structures: equal variance or spike-shaped. Dominance results are presented to identify the set of stations and the amount of reduction in an optimal solution.
Identifying and Structuring Values to Guide Integrated Resource Planning at BC Gas
Authors: Keeney Ralph L. , McDaniels Timothy L.
Published: November 2008

British Columbia Gas, a major utility, was required by the British Columbia Utilities Commission (BCUC) to develop an integrated resource plan that addressed multiple objectives and involved the participation of stakeholders. To assist BC Gas, we elicited values separately from most of the senior executives at BC Gas, members of the BCUC, and representatives of several stakeholder groups. Based on these values, we structured a set of objectives and associated performance measures for integrated resource planning (IRP) at BC Gas. A multistakeholder process then provided judgments about appropriate value tradeoffs among these objectives. This information was used in several ways in the IRP process. It fostered improved communication and served as a guide for designing more attractive plans and identifying future information needs. It also provided the basis for a quantitative evaluation of alternative plans and resources. Both the IRP process and the chosen integrated resource plan were reviewed by lawyers representing intervenors at a quasi-judicial hearing of the BCUC. Their concerns are informative in providing lessons for the use of the elicited values in the context of regulatory hearings.
Using Analogical Reasoning and Schema Formation to Improve the Success in Formulating Linear Programming Models
Authors: Murphy Frederic H. , Panchanadam Venkat
Published: November 2008

In this paper we look at alternative ways of teaching linear programming model formulation and show that the material needs to be presented within the context of a structure that improves the ability of students to apply the models to subsequent problems. This work builds on the cognitive psychology literature on formulating algebra word problems. We show that presenting a conceptual framework prior to teaching linear programming examples is better then either no conceptual framework or presenting the framework after teaching the examples.
Asymptotic Mean and Variance of Electric Power Generation System Production Costs via Recursive Computation of the Fundamental Matrix of a Markov Chain
Authors: Shih Fen-Ru , Mazumdar Mainak , Bloom Jeremy A.
Published: November 2008

The cost of producing electricity during a given time interval is a random variable that depends both on the availability of the generating units during the study horizon and on the magnitude of the load. Based upon a Markov model, we present a recursive scheme for estimating the asymptotic mean and variance of the production cost. These computations are difficult because the state space for a typical power generation system is very large and because the asymptotic variance depends upon the fundamental matrix. Its computation requires the inversion of a matrix whose dimension depends on the size of the state space. The recursion relations given here preclude the need for such matrix inversion and provide approximate estimates that compare very favorably with a realistic Monte Carlo simulation.
A Heuristic Method for the Set Covering Problem
Authors: Caprara Alberto , Fischetti Matteo , Toth Paolo
Published: November 2008

We present a Lagrangian-based heuristic for the well-known Set Covering Problem (SCP). The algorithm was initially designed for solving very large scale SCP instances, involving up to 5,000 rows and 1,000,000 columns, arising from crew scheduling in the Italian Railway Company, Ferrovie dello Stato SpA. In 1994 Ferrovie dello Stato SpA, jointly with the Italian Operational Research Society, organized a competition, called FASTER, intended to promote the development of algorithms capable of producing good solutions for these instances, since the classical approaches meet with considerable difficulties in tackling them. The main characteristics of the algorithm we propose are (1) a dynamic pricing scheme for the variables, akin to that used for solving large-scale LPs, to be coupled with subgradient optimization and greedy algorithms, and (2) the systematic use of column fixing to obtain improved solutions. Moreover, we propose a number of improvements on the standard way of defining the step-size and the ascent direction within the subgradient optimization procedure, and the scores within the greedy algorithms. Finally, an effective refining procedure is proposed. Our code won the first prize in the FASTER competition, giving the best solution value for all the proposed instances. The algorithm was also tested on the test instances from the literature: in 92 out of the 94 instances in our test bed we found, within short computing time, the optimal (or the best known) solution. Moreover, among the 18 instances for which the optimum is not known, in 6 cases our solution is better than any other solution found by previous techniques.
A Fully Polynomial Approximation Scheme for the Weighted Earliness–Tardiness Problem
Authors: Kovalyov Mikhail Y. , Kubiak Wieslaw
Published: November 2008

A fully polynomial approximation scheme for the problem of scheduling n jobs on a single machine to minimize total weighted earliness and tardiness is presented. A new technique is used to develop the scheme. The main feature of this technique is that it recursively computes lower and upper bounds on the value of partial optimal solutions. Therefore, the scheme does not require any prior knowledge of lower and upper bounds on the value of a complete optimal solution. This distinguishes it from all the existing approximation schemes.
Warranty Economic Decision Models: A Summary and Some Suggested Directions for Future Research
Authors: Thomas Marlin U. , Rao Sridevi S.
Published: November 2008

Product guarantees or warranties have been around for generations, but formal approaches for establishing and examining warranties have been considered only during the past 20 years. A review of the literature on warranty models and analysis methods is provided, along with some suggestions for further research.
Scheduling in Robotic Cells: Heuristics and Cell Design
Authors: Kamoun Hichem , Hall Nicholas G. , Sriskandarajah Chelliah
Published: November 2008

This paper considers scheduling problems arising in robot-served manufacturing cells in which the machines are configured in a flowshop that repetitively produces a family of similar parts. We study the problem of determining the robot move cycle and the part sequence that jointly minimize the average steady-state cycle time required for the repetitive production of a minimal part set, or equivalently maximize the long-run throughput rate. Three earlier related papers provide algorithms, or proofs of intractability, for a variety of cell configurations. We use the intuition developed there to design and test simple heuristic procedures for the part sequencing problem under different robot move cycles in three-machine cells where that problem is intractable. This enables us to develop a heuristic procedure for a general three-machine cell. A methodology for extending this heuristic to four-machine cells is described and tested. Ideas for extension to even larger cells are also discussed. We also describe and test two heuristics for a cell design problem that involves partitioning machines into cells as well as determining the sequence of robot moves and parts. Finally, we provide a list of open research problems.
Letter to the Editor—A Proposal for Merging ORSA and TIMS
Authors: Lathrop John B.
Published: November 2008

It is desirable that the Operations Research Society of America and The Institute of Management Sciences be merged, and the time for this merger is ripe.
Economic-Lot-Size Formulas in Manufacturing
Authors: Vazsonyi Andrew
Published: November 2008

Economic-lot-size formulas result in order quantities that minimize combined inventory and set-up (and ordering) costs. In manufacturing problems, economic-lot-size formulas may result in unrealizable schedules—in some production periods the shop may not be able to meet requirements, whereas at other times slack periods that result in idleness may occur. This paper describes a technique that permits the computation of order quantities so that requirements are met with available labor and machines. The technique involves a simple step-by-step computation particularly adaptable to electronic computers.
Bombing Problems—A Statistical Approach
Authors: Laurent Andre G.
Published: November 2008

Bombing problems are studied from the viewpoint of statistical inference and from the viewpoints of the bomber and its opponent. The probability of a hit inside a circle centered at the target is given. A method is proposed to obtain the “best” estimate of the probability of a hit in a given area, with a known or unknown target, on the basis of the information given by the points of impact during a flight. The method is applied to the cases of a rectangle and of a circle centered at the (known) target. Methods of approximation for any area are given. The problem of “dangerous” and “safe” regions is discussed. A method to obtain “distribution free” safe regions is proposed and conditions to obtain “safe” regions with a given confidence level are stated. Two examples of “safe confidence regions” are given.
Some Factors Tending to Limit the Utility of the Social Scientist in Military Systems Analysis
Authors: Michael Donald N.
Published: November 2008

What I am about to discuss should not be construed as pessimistic or negative since I have considerable hope for the future of the social sciences as a resource in military systems analysis. However, it has been my experience, and that of other social scientists, that there are certain difficulties which, when they arise, tend to limit our present value as a military resource. These difficulties seem more often to arise when the subject of evaluation is behavioral or institutional stress, though they are not the exclusive characteristics of a particular work problem. To the extent that an appreciation of these difficulties can provide conditions which encourage the reduction of their significance or prevalence, to that extent we will increase our utility in this field of research and application. This is a slightly revised version of an address delivered at the panel on Problems and Prospects for Military Sociology at the American Sociological Society, September 9, 1956. These comments do not necessarily reflect the views of any organizations with which the writer has been affiliated.
On a Problem of Production Scheduling
Authors: Bishop George T.
Published: November 2008

In a recent paper, Bowmar showed that the problem of balancing costs of overtime production and inventory storage to minimize the total cost of meeting given sales requirements can be set up as a transportation problem. Accordingly, he suggested the use of the Stepping Stone Method of Charnes and Cooper for the solution of this problem. The present paper discusses features of the cost matrix that lead to a simplified method of solution.
Optimum Component Redundancy for Maximum System Reliability
Authors: Gordon Robert
Published: November 2008

The method of increasing the reliability of a complex system by adding redundant components is examined using the criterion that inadvertent operation of a component (which is a possible mode of component failure) may lead to failure of the system. On this basis the use of an infinite number of redundant components leads to zero system reliability instead of 100 per cent system reliability. A simple model of a system consisting of off-on-off components is analyzed using separate probabilities for non-operation and for inadvertent operation. Considering only the effects of redundancy, it is shown that maximum system reliability occurs with a relatively small number, m, of redundant components. The value of m depends on the values of the two separate probabilities. Curves are presented which show the effect of the number of redundant elements, m, on system reliability as a function of the two separate component probabilities. The ratio, k, between failures due to non-operation and failures due to inadvertent operation permits estimation of the two separate reliabilities used in the analysis from the conventional definition of component reliability.
Letter to the Editor—A. K. Erlang
Authors: Saaty Thomas L.
Published: November 2008

I feel that it would be appropriate if the Journal would publish some highlights of the life of A. K. Erlang, whose ideas and work in telephony anticipated by almost half a century the modern concepts of queuing theory. The following remarks are all taken from The Life of A. K. Erlang, by E. Brockmeyer and H. L. Halstrom (Transactions of the Danish Academy of Technical Sciences, 1948, No. 2, pp. 16–18).
Letter to the Editor—A Proposed Measure for Determining the Value of a Design
Authors: Epstein L. Ivan
Published: November 2008

Situations continually arise in engineering design work where a choice must be made between alternatives. Typically, a design may be modified to improve it in one respect with resulting impairment in another respect. In such a case, the two opposing results must be weighted and a decision must be made. The following is an attempt to give a function of the design parameters, which yields the over-all value of the design.
Letter to the Editor—Proposed Amendments to the Constitution
Authors: Brothers LeRoy A.
Published: November 2008

The Council of the Society has proposed amendments to the Constitution which will be discussed at the Annual Meeting in May 1957 and then will be voted on by mail ballot.
Letter to the Editor—Comments on Precoda's Paper on Air Weapons Systems Analysis
Authors: Lathrop John B.
Published: November 2008

It would be very unfortunate if the readers of Operations Research were to judge the state of the art in systems analyses of aircraft bombing systems from Precoda's paper on “Air Weapons Systems Analyses” [Opns. Res. 4, 684–698 (December 1956)]. The author is perhaps forced to appear somewhat naive by reason of writing on a subject for which the extensive literature and methodology appear in classified reports.
A Comparison of the Original and Revised Simplex Methods
Authors: Wagner Harvey M.
Published: November 2008

The procedure for the revised simplex method is outlined by making use of only the rudiments of matrix algebra. For a typical simplex iteration, a step by step comparison is made between the calculations for the revised and the original method. Finally, several reasons for recommending the revised method are briefly discussed.
Distribution of Seasonal Inventory of the Hawaiian Pineapple Company
Authors: Eagle Alan R.
Published: November 2008

This paper describes a program developed for the Hawaiian Pineapple Company, Ltd., to reduce inventory costs incurred in the distribution of canned pineapple products. The Dole plantations harvest about 75 per cent of their total annual crop during the five summer months, thus creating large canned goods inventories. These inventories are stored in the Company's Honolulu warehouse and at commercial warehouses on the U.S. mainland. The mainland warehouses store a portion of the seasonal inventories and also provide forward supply points for the Company's buyers, but at considerable expense. An inventory-control model was developed to determine the required inventory at each warehouse for specified protection against an out-of-stock condition. A procedure was developed for allocating inventories in excess of those needed for immediate sales requirements among the available storage points to minimize the total annual warehousing cost. The procedure takes into account the different storage, handling, and tax costs at the various locations and all relevant operating requirements. The principles involved are explained by a graphical approach, which is easy to understand and which facilitates changing the allocation rules in response to changes in operating conditions. The program has been adopted by the Company's management and steps are in progress to incorporate the recommendations in the Company's inventory distribution operations.
A Monte Carlo Analysis of the Ground Controlled Approach System
Authors: Blumstein Alfred
Published: November 2008

The Ground Controlled Approach (GCA) is an all-weather landing system in which a ground controller, watching the landing airplane on a radar scope, transmits maneuver orders to produce a proper approach path. By a Monte Carlo analysis of this system, it has been possible to estimate the distribution of airplane positions along the approach path, and the probability of a successful landing. Sample flight paths have been simulated by using random numbers to represent the stochastic variations in initial position, wind, controller decisions, and execution of turn orders.
A Hand-Computation Determination of Kill Probability for Weapons Having Spherical Lethal Volume
Authors: Lilliefors H. W.
Published: November 2008

A method suitable for hand computation is presented for determining the probability of killing a point target when (a) the lethal volume is a sphere centered on the burst point of the weapon, and (b) the distribution of the weapon's burst points is described by a three-dimensional multivanate normal distribution about the target.
Letter to the Editor—What is a System?
Authors: Hoag Malcolm W.
Published: November 2008

When a scientist of almost any specialty asks what Operations Research or Systems Analysis is, we can take it for granted that he knows the meaning of research and analysis. But this leaves an embarrassing question.
Operations Research and National Planning
Authors: Ackoff Russell L.
Published: November 2008

I want to apologize in advance for what I am about to do to you. My presentation will not be in the relaxed spirit of this occasion, nor will it be entertaining. In fact it will be very trying to you. My only excuse for such behavior is the deep conviction that my subject is a very important one. I wish I were as convinced that my treatment of it merits using this opportunity in the way that I am going to. The subject is “Operations Research and National Planning.” Retiring Presidential Address at the banquet of the Fifth Annual Meeting of the Operations Research Society of America, Philadelphia, Pennsylvania, May 9, 1957.
Networks of Waiting Lines
Authors: Jackson James R.
Published: November 2008

One of the least understood classes of operations problems is that concerned with the design, loading, and, especially, the scheduling of discrete, statistically varying flows through complex networks. The present paper abstracts what is perhaps the simplest theoretical question related to this class of problems, and derives expressions for certain steady-state parameters.
An Operations-Research Study of the Collection of Defaulted Loans
Authors: Mitchner Morton , Peterson Raymond P.
Published: November 2008

Statistical decision techniques are developed for loan screening that provide a guide as to how long nonpaying defaulted loans of various types should be pursued by adjusters or collectors before they are completely dropped as uncollectible. A mathematical model yields the optimum pursuit duration and maximum expected net profit for each type of delinquent loan considered and which, if followed, will maximize the over-all net profit of a loan adjustment or collection department. The application of these rules by simulation to a random sample of defaulted loans indicates a potential increase in net profit of approximately 33 per cent.
The Theory of Search
Authors: Koopman Bernard O.
Published: November 2008

This is Part III, concluding the series of three papers on The Theory of Search Part I, Kinematic Bases, appeared in Opns. Res. 4, 324–346 (1956) and Part II, Target Detection, in 4, 503–531 (1956). The present paper, while similar in content and results to the third chapter of Search and Screening (O.E.G. Report No. 56, confidential) represents a considerable change in methodology as well as in exposition. The material was first presented by the author at the fall meeting of the Operations Research Society of America in 1953, where it was treated as a natural extension of his paper, The Optimum Distribution of Effort [this Journal, 1, 52–63 (1953)].
An Equipment-Investment Analog
Authors: Fetter Robert B. , Goodman Thomas P.
Published: November 2008

This study was instituted to explore the feasibility of solution of an economic model for equipment investment by an analog computer. The relevance of various models to the equipment-replacement model is discussed and the equivalence of these shown. An analog is constructed and computations made for a wide range of system parameters. The sensitivity of the decision to changes in the values of the factors considered is analyzed and conclusions drawn.
Letter to the Editor—Operations Research and National Planning—A Dissent
Authors: Hitch Charles
Published: November 2008

When Russell Ackoff made his eloquent plea at the Philadelphia meeting for operations researchers to help underdeveloped countries with their national economic planning, I felt compelled to register a qualified dissent. Now that his address has been published in Operations Research (August 1957, pp. 457–468), I should like to take advantage of a generous suggestion by the author that I present my dissenting point of view to members of the Society.
The Application of a High Speed Computer to the Definition and Solution of the Vehicular Traffic Problem
Authors: Goode Harry H.
Published: November 2008

After an examination of the methodology used by the operations researcher, it becomes clear that the mathematical model is central to this methodology. It therefore becomes of interest to examine mathematical models. The latter are classified into analytic and numerical, as well as into deterministic or stochastic. Attention is then centered on the numerical stochastic model. The use of a computer in this connection is explored and the resulting model is discussed from the standpoint of operations-research methodology—all in connection with the vehicular traffic problem. Conclusions are drawn concerning the estimated usefulness of such a model in the future.
Letter to the Editor—Graphic Solution of the Traveling-Salesman Problem
Authors: Barachet L. L.
Published: November 2008

The traveling-salesman problem consists in selecting from a total number of closed-circuit routes all passing through a number N of given points the one shortest route. To consider all the possible circuits would lead to excessive computations. However, this problem may be solved practically by using a simple, essentially intuitive method.
Letter to the Editor—Comments on “A Possible Solution to the Shortage of Scientists”
Authors: Andrews Thomas G. , Kahn Lessing A.
Published: November 2008

We have read with some interest the paper of the above title by Taylor and Balloch in the June 1957 issue of this Journal (vol. 5, pp. 311–318).
Letter to the Editor—Errors of Estimate in Operations Analysis
Authors: Peters George A.
Published: November 2008

The effectiveness of military weapons is often determined by rigorous study of the appropriate weapons-system components and their interaction. The criterion of effectiveness is usually defined in terms of tactical needs in combat situations. Unfortunately, it is not always possible to check on the validity of such effectiveness estimates, since there are some very practical limitations imposed upon the setting-up and conduct of real life tests of military weapons.
Errata
Authors: Marshall Byron O. , Boggess William P.
Published: November 2008

Correction to the authors' paper “The Practical Calculation of Reorder Points” Operations Research, vol. 5, pp. 513–517 (August 1957).
Education in Operations Research at the Ohio State University
Authors: Morris W. T.
Published: November 2008

The Educational Program in Operations Research at Ohio State is centered in the Department of Industrial Engineering, within which the academic aspects of the program are organized, and in the Operations Research Group of the Engineering Experiment Station, which engages in contract research and serves as a laboratory for the academic program. The Operations Research Group was established in 1954 to provide opportunities for actual experience in operations research as an essential aspect of training in this area, and to provide conditions under which a program of basic research could be developed.
Heuristic Problem Solving: The Next Advance in Operations Research
Authors: Simon Herbert A. , Newell Allen
Published: November 2008

Address at the banquet of the Twelfth National Meeting of the Operations Research Society of America, Pittsburgh, Pennsylvania, November 14, 1957. Mr. Simon presented the paper; its content is a joint product of the authors. In this, they rely on the precedent of Genesis 27:22, “The voice is Jacob's voice, but the hands are the hands of Esau.”
Letter to the Editor—Written in a Queue
Authors: Ellis H. F.
Published: November 2008

An article reproduced from Punch.
Letter to the Editor—Incidental Intelligence
Authors: Chow W. M.
Published: November 2008

The following bit of information was discovered by accident “Directory of Newspapers and Periodicals,” 1957 Edition, published by N. W. Ayers and Sons, Philadelphia, lists on page 1458, Operations Research, Journal of the Operations Research Society of America, under the classification of “Medical and Surgical.”
Link-Length Minimization in Networks
Authors: Miehle William
Published: November 2008

Three general methods are described for attacking link-length minimization problems. All methods assume a system of fixed points that are to be interconnected by a network of links the sum of whose lengths is a minimum. In the mechanical and numeric-analytic methods, the interconnections are made through a specified number of junction points whose locations are to be determined although the connections thereto are specified initially. Constraints on the variable points and weighting of links are possible. In the soap-film method, network configurations are produced directly without assuming variable points or junctions.
Letter to the Editor—Production and Inventory Planning in a Fluctuating Market
Authors: Dano Sven , Jensen Ernst Lykke
Published: November 2008

Discussion about an important contribution to the theory of inventory planning by F. Modigliani and F. E. Horn (F. Modigliani and F. E. Hohn, “Production Planning Over Time and the Nature of the Expectation and Planning Horizon,” Econometrica, vol. 23, No. 1 (1955). A similar model was developed by Schneider in 1938, cf. E. Schneider, “Absatz, Produktion und Lagerhaltung bei einfacher Produktion,” Archiv für mathematische Wirtschafts und Sozialforschung 4 (1938), and T. M. Whitin, “Erich Schneider's Inventory Control Analysis,” Opns Res 2, 329–334 (1954).).
Simulation Techniques in Operations Research—A Review
Authors: Harling John
Published: November 2008

The purpose of this paper is to give an introductory account of the techniques of simulation, to present a few of the leading ideas which have been developed, and to draw attention to what is in fact a very open and somewhat ill-defined subject.

Considerable confusion exists over the best terminology to use. The term ‘Monte Carlo’ is presently somewhat fashionable, the term ‘simulation’ is to be preferred, because it does not suggest that the technique is limited to what is familiar to statisticians as a sampling experiment.

By simulation is meant the technique of setting up a stochastic model of a real situation, and then performing sampling experiments upon the model. The feature which distinguishes a simulation from a mere sampling experiment in the classical sense is that of the stochastic model. Whereas a classical sampling experiment in statistics is most often performed directly upon raw data, a simulation entails first of all the construction of an abstract model of the system to be studied.
Application of Operations Research to Development Decisions
Authors: Klein Burton , Meckling William
Published: November 2008

It is the main argument of this paper that an efficient allocation of the development budget is a very different sort of a problem from the efficient conduct of a current operation. We attempt to show that the problem is essentially not one of choosing among specific end-product alternatives, but rather a problem of choosing a course of action initially consistent with a wide range of such alternatives, and of narrowing the choice as development proceeds. The implications, for the analyst, of viewing the development problem as this kind of problem are sketched in the concluding section of the paper.
Optimum Lot Sizes for Parts Used in Aircraft Production
Authors: Chambers John C. , Bond Angus F. , Leake James H.
Published: November 2008

In the treatment of most inventory problems, obsolescence is either ignored or a constant factor is included in the inventorycarrying cost to account for obsolescence. However, the high obsolescence rate of detailed parts in the aircraft industry necessitates a more precise consideration of obsolescence. A method is developed for evaluating and including obsolescence costs in an inventory model. Other important and unusual factors in this inventory situation are (a) a demand rate that increases irregularly until the maximum rate is reached and (b) splitting of lots in the shop.
Optimizing a Catalytic Cracking Operation by the Method of Steepest Ascents
Authors: Schrage Robert W.
Published: November 2008

The optimization of complicated nonlinear systems, involving many variables and constraints, is a familiar problem in the chemical and petroleum industries. A typical example occurred in trying to find the optimum operating conditions for a fluid catalytic cracking unit. As a first step in investigating this particular problem, an elaborate mathematical model of the catalytic cracking operation was developed. When programmed on a large-scale digital calculator, this model permitted convenient simulation of both the engineering and economic aspects of the system. However, the number of variables subject to control, and the complicated relationships between them, precluded the use of any haphazard approach to finding the optimum operating conditions. The method of steepest ascents (taken from a part of the Box-Wilson technique for designed experiments) and linear programming were used to develop a rational sequential method for solving this problem. These methods optimized six key variables, subject to various operating constraints. The study was completed in a reasonable time and at a moderate cost. A substantial economic advantage was indicated between the final solution and the base case chosen to initiate the study.
Long Range Planning—A Kaleidoscopic View
Authors: Stewart Earle
Published: November 2008

In recent years, corporate planning of a formal nature has expanded markedly. Surveys by the Stanford Research Institute, Business Week magazine, the National Industrial Conference Board, and the American Management Association disclose an increasing number of large firms adopting more formalized planning. This increase has been especially marked in the past five years, with the last several years particularly productive of papers on the applications of “scientific” approaches to corporate long-range planning. But organized planning has not always had such support.
A Working Model of the Financial Dynamics of a Business
Authors: Whitney Bernard , Israel Marion S.
Published: November 2008

In this paper we do not propose to analyze whether traditional accounting statements portray the true financial picture. Nor is there need to elaborate on the time and labor required for the compilation of modern accounting statements. With few exceptions, businessmen consider them excessive, although many in the accounting field disagree. An extension of the method suggested here has made possible the successful solution of complicated accounting problems taken from CPA examinations in less than one-third the usual time.
Cargo Containerization in the West Coast-Hawaiian Trade
Authors: Weldon Foster L.
Published: November 2008

This paper is a summary account of a detailed systems study carried out for the top management of the Matson Navigation Company as a part of their long-range planning program. The basic question to which the study addresses itself is whether or not the company should develop and operate a cargo-container shipping service as an integral part of its West Coast-Hawaiian shipping operations.
Game-Theory Models in the Allocation of Advertising Expenditures
Authors: Friedman Lawrence
Published: November 2008

The allocation of advertising expenditures by area and by media is a problem faced by most marketing organizations. The problem with certain assumptions can be treated with some of the techniques of game theory. In this paper several mathematical models will be described along with their solutions. The models are theoretical and are based on various assumptions about the effect of advertising on sales. The validity of these assumptions as well as the possible application of these models is discussed.