bluuebunny/crossref_metadata_2025 huggingface dataset:
Pricing Model for a Computer Center
Authors: Babad Yair M.
Published: November 2008

Managers of computer systems are interested in increased utilization of their resources, which include processing (time) capacity and various storage devices, as well as in attracting more users and revenues. To increase utilization of the system, resources have to be rationed: users' processing has to be scheduled to less utilized time slots (that is, nonpeak hours), and storage and processing capacity have to be properly allocated. This rationing may be achieved by administrative ruling, which might aggravate users and reduce the attractiveness of the system, or by an appropriate pricing policy and free market forces. In this paper the second approach is considered, and a general equilibrium model which takes into account both the system needs and the users' cost and satisfaction is presented. The model is shown to fit many marketing situations, which extends its usability beyond the scope of computer systems. Two heuristic algorithms are used to solve this model: a cobweb type algorithm, and a modified Simplex algorithm. The use of the model is illustrated by an actual pricing problem at a university computing center.
Decision Analysis in Microelectronic Reliability: Optimal Design and Packaging of a Diode Array
Authors: Ronen Boaz , Pliskin Joseph S.
Published: November 2008

This paper considers quantitative aspects in microelectronic reliability using decision analysis. In a given electronic system, a diode array (i.e., system of switches) serves as a built-in test circuit. Failure of a single component can disrupt system performance. Two failure modes are possible, short or open circuit, each resulting in different damages to the system. The decision analysis considers aspects of circuit design and packaging technology. Design involves a conventional system or one with redundancy. Important considerations are cost, total failure rate, proportion of each failure mode and malfunction costs. Three alternative packaging technologies are considered. Optimal design and packaging are determined in two alternative ways: using expected monetary costs, and using expected utility. The method and results were implemented in the Israeli electronics industry. The method has also been implemented in other areas with similar decision problems (e.g., cardiac pacemakers).
Market Equilibrium Computations in Activity Analysis Models
Authors: Norton Roger D. , Scandizzo Pasquale L.
Published: November 2008

This paper shows how an approximate competitive market equilibrium may be computed as the solution to a linear programming model, when production possibilities are described by activity analysis vectors and demand functions are locally linear. Numerical examples show that the degree of approximation may be expected to be very small in many cases. Prices and quantities of goods and resources and also incomes are explicit in the primal. (The defining characteristics of a market equilibrium are written as primal constraints.) Linearizations of inherently nonlinear expressions are attained by use of grid linearizations and the associated interpolation variables.
Determination of Optimal Variable-Sized Multiple-Block Appointment Systems
Authors: Fries Brant E. , Marathe Vijay P.
Published: November 2008

The single-block appointment system is the most common method of scheduling ambulatory care clinics today. Several studies have examined various appointment systems ranging from single-block appointments on one extreme to individual appointments on the other, and including mixtures of these such as multiple-block (m-at-a-time) and block/individual systems. In this paper we analyze a general single-server multiple-block system, one permitting blocks of variable size. In the analysis we use a dynamic programming approach, with some modifications to compensate for the non-Markov nature of the problem. Analytical results and approximations which significantly reduce the computational requirements for a solution are obtained. Examples demonstrate that under certain weightings of the criteria of waiting, idle, and overtime, the generality of the system considered here allows performance superior to that of other commonly used systems.
The Deterrent Effect of Capital Punishment: A Test of Some Recent Studies
Authors: Barnett Arnold
Published: November 2008

Three recent regression-based statistical studies on the deterrent effect of capital punishment are examined. Evidence is presented that their underlying mathematical models are subject to large systematic error of unknown cause and that, in consequence, one cannot have strong confidence in their conclusions. In addition these models are recalibrated under a modification of their assumptions about “random error” that is implied by our analysis.
Technical Note—Note on Constrained Maximization of a Sum
Authors: Washburn Alan R.
Published: November 2008

Use of a Lagrange multiplier in optimization problems often requires a search with the object of finding the multiplier for which some constraint is met. We introduce a technique that, under some severe assumptions, finds the correct multiplier in a finite number of steps.
Technical Note—Extension of the Luss-Gupta Resource Allocation Algorithm by Means of First Order Approximation Techniques
Authors: Einbu John M.
Published: November 2008

A resource allocation algorithm proposed by Luss and Gupta is extended by the introduction of a numerical method for the optimal distribution of a continous resource among preselected activities as an option to the analytical method applied in the original algorithm. The numerical method allows return functions which cannot be dealt with by the analytical method. An integral part of the numerical method is a composite recurrence relation obtained from the Kuhn-Tucker conditions of the problem with linear functions substituted for the derivatives of the return functions. The convergency of the recurrence process is proven for a class of return functions.
A Review of Production Scheduling
Authors: Graves Stephen C.
Published: November 2008

Production scheduling can be defined as the allocation of available production resources over time to best satisfy some set of criteria. Typically, the scheduling problem involves a set of tasks to be performed, and the criteria may involve both tradeoffs between early and late completion of a task, and between holding inventory for the task and frequent production changeovers. The intent of this paper is to present a broad classification for various scheduling problems, to review important theoretical developments for these problem classes, and to contrast the currently available theory with the practice of production scheduling. This paper will highlight problem areas for which there is both a significant discrepancy between practice and theory, and for which the practice corresponds closely to the theory.
Analytical Evaluation of Hierarchical Planning Systems
Authors: Dempster M. A. H. , Fisher M. L. , Jansen L. , Lageweg B. J. , Lenstra J. K. , Rinnooy Kan A. H. G.
Published: November 2008

Hierarchical planning systems have become popular for multilevel decision problems. After reviewing the concept of hierarchical planning and citing some examples, we describe a method for analytic evaluation of a hierarchical planning system. We show that multilevel decision problems can be nicely modeled as multistage stochastic programs. Then any hierarchical planning system can be measured against the yardstick of optimality in this stochastic program. We demonstrate this approach on a hierarchical system that can be shown to be asymptotically optimal for a job shop design/scheduling problem.
Equalization of Runout Times
Authors: Karmarkar Uday S.
Published: November 2008

The Equalization of Runout Times (ERT) rule has been suggested as a heuristic for allocating production capacity across a group of items with a common set up cost. A natural interpretation of this rule is given by showing that for a single allocation under certain conditions it maximizes the time at which the group will next be scheduled. An equivalent interpretation is that the rule minimizes remnant stocks. The case of multiple allocations is studied next and it is shown that applying the ERT rule myopically, minimizes the sum of discounted setup costs.
A Nonlinear Network Flow Algorithm for Maximization of Benefits in a Hydroelectric Power System
Authors: Rosenthal Richard E.
Published: November 2008

A nonlinear network flow algorithm for maximization of benefits in a multireservoir hydroelectric power system is presented. The problem was posed by Tennessee Valley Authority (TVA) as an optimization model with a nonseparable nonlinear objective function and with linear network flow constraints. The proposed algorithm is based on reduced gradient methodology (with somewhat nonstandard modifications) and on primal linear network flows (with simplifications resulting from the special structure of the problem network). An unusual feature of the algorithm is an integer programming subproblem whose exact solution determines the superbasic set and the search directions. The algorithm is coded by means of an efficient basis-tree labeling system which consists of a single node-length array and which is specifically designed for the physical context of the problem. Test problems on a 6-reservoir TVA subsystem were solved with computer costs well within the “affordable” range.
The Multiregion Dynamic Capacity Expansion Problem, Part II
Authors: Fong C. O. , Srinivasan V.
Published: November 2008

Consider the problem of determining a schedule of capacity expansions for m producing regions and a schedule of shipments from the regions to the n markets so as to meet the market demands over a T-period planning horizon at minimum discounted capacity expansion and shipment costs. The capacity expansion costs are assumed to be in the form of a fixed charge plus a cost proportional to the size of the expansion and the shipment costs are assumed to be proportional to the amounts involved. The heuristic algorithm of this paper improves on feasible solutions by the exchange of capacities between pairs of regions. The algorithm imbeds a branch and bound procedure to determine the optimal amounts for the pair-wise exchange of capacities and uses as a subroutine the corresponding algorithm for linear capacity expansion costs developed in an earlier paper. Computational results for both real and randomly generated problems show that the heuristic algorithm is computationally efficient and yields close to optimum solutions.
M/G/1 Queues with Scheduling within Generations and Removable Server
Authors: Shanthikumar J. G.
Published: November 2008

Two models of M/G/1 queues with removable server and scheduling within generations are considered in this paper. The scheduling policy considered here is the shortest processing time; the control policies are the multiple vacations policy and N-control policy. The Laplace-Stieltjes transforms of the waiting time distribution, the mean cost rates and the optimal control policies are derived for these two models. Properties of the delayed busy cycle are used in our analysis.
Branch and Bound Methods for Multi-Item Scheduling
Authors: Sweeney Dennis J. , Murphy Richard A.
Published: November 2008

This paper presents two solution approaches for the multi-item activity scheduling problem; a problem of practical importance because it models many resource allocation and combinatorial problems. Both approaches are easily incorporated into commercially available linear programming (LP) based branch-and-bound codes such as IBM's MPSX370-MIP. Many practitioners rely on such codes and will find these approaches useful. The first approach is a specialization of a method for decomposing integer programs with block angular structure. In the second approach, the reduced costs in the solution to the usual LP relaxation are used to develop improved priorities for branching. Computational results on real applications are reported using MPSX 370-MIP.
Markov Chain Design Problems
Authors: Evans Richard V.
Published: November 2008

System design problems using Markov chains and denoted Markov chain design problems are introduced. It is assumed that the chains of the problem have transition matrices and one period conditional expected rewards which are differentiable functions of a vector parameter. A gradient algorithm for maximizing the sum of the discounted expected reward or the limit of the one period expected reward is presented. The algorithm uses approximate objective function values and approximate gradients at each stage. Numerical work on a simple one dimensional queueing model solved the design problem correctly and quickly even though minimal approximation accuracy was used. The convergence of the approximation is proven for an appropriately converging sequence of design parameter values.
The Design of Distributed Service Systems
Authors: Strip David R. , Engelbrecht-Wiggans Richard
Published: November 2008

A variety of practical situations involve supplying a particular commodity by some locations to satisfy the demand at others. If the demands and the costs of producing varying amounts of commodity at each location are known, then the question is how much commodity should be supplied by each location in order to minimize the total system cost. Under some relatively general conditions, there will be an optimal solution with the property that the vector of amounts supplied by the various locations is one of a distinguished set of points. In the case of star networks, this combinatorial nature may be exploited to give a very efficient algorithm for finding an optimal solution. A numerical example illustrates the results.
Myopic Solutions of Markov Decision Processes and Stochastic Games
Authors: Sobel Matthew J.
Published: November 2008

Sufficient conditions are presented for a Markov decision process to have a myopic optimum and for a stochastic game to possess a myopic equilibrium point. An optimum (or an equilibrium point) is said to be “myopic” if it can be deduced from an optimum (or an equilibrium point) of a static optimization problem (or a static [Nash] game). The principal conditions are (a) each single period reward is the sum of terms due to the current state and action, (b) each transition probability depends on the action taken but not on the state from which the transition occurs, and (c) an appropriate static optimum (or equilibrium point) is ad infinitum repeatable. These conditions are satisfied by several dynamic oligopoly models and numerous Markov decision processes.
Optimal Smoothing Rules for University Financial Planning
Authors: Massy William F. , Grinold Richard C. , Hopkins David S. P. , Gerson Alejandro
Published: November 2008

The determination of each year's endowment payout, total spending, and transfers to or from reserves is set up as an optimal smoothing rule problem. Stochastic laws of motion are formulated for total spending, operating income, changes in the balances for endowment and operating reserves, and the acquisition of new gifts to endowment. Parameters of the smoothing rules are obtained by making subjective tradeoffs among objectives such as the means and meansquare deviations of budget quantities and the probabilities that these quantities will exceed certain control limits. The model currently is being used to determine the endowment payout rate for Stanford University.
Optimal Whereabouts Search for a Moving Target
Authors: Stone Lawrence D. , Kadane Joseph B.
Published: November 2008

This paper shows that solving the optimal whereabouts search problem for a moving target is equivalent to solving a finite number of optimal detection problems for moving targets. This generalizes the result of Kadane (Kadane, J. B. 1971. Optimal whereabouts search. Opns. Res. 19 894–904.) for stationary targets.
Congestion Formulas for a Heterogeneous Server Loss System with Random Selection Discipline
Authors: Kaufman J. S.
Published: November 2008

A heterogeneous server loss model which has found considerable use in modeling faulty trunk circuits is studied. The server selection discipline is random, service time distributions are general and the arrival process is Poisson. Results obtained include closed form expressions for the server occupancies and group blocking which involve only the well studied and tabulated Eriang Loss Function. The results are useful for the insight they yield about system behavior, as well as the ease with which numerical results can be obtained.
Technical Note—Analysis of a Preference Order Traveling Salesman Problem
Authors: Sniedovich Moshe
Published: November 2008

Application is made to the preference order dynamic programming solution procedure proposed by Kao for a stochastic traveling salesman problem. Although the procedure is flawed from the myopic interpretation of the monotonicity condition, it may be used as a convenient heuristic tool for solving stochastic problems.
Observation, Experiment, and Measurement in Operations Research
Authors: Solandt Omond
Published: November 2008

Talk presented at the Informal Seminar in Operations Research, The Johns Hopkins University, April 6, 1954.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Letter to the Editor—A Note on Amusement Park Economics
Authors: Platt William J.
Published: November 2008

The news in the amusement-park industry, and in Walt Disney's weekly ABC-TV series, is the building of Disneyland, described by the Disney studio as “a combination world's fair, playground, museum of living facts, and show-place of beauty and magic.” In helping Walt Disney select a site for Disneyland and plan its economics, we found that the amusement-park industry is not all fantasy: it offers some intriguing opportunities for quantitative research on operations.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Letter to the Editor—Why Operations Research?
Authors: Johnson W. T. M.
Published: November 2008

No abstract available.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Letter to the Editor—Comments on “Threats to the Growth of Operations Research”
Authors: Brigham Georges
Published: November 2008

I should like to comment on the points mentioned by Dr. Rinehart at the May meeting and in his article in the August issue of the Journal, in the same order which he followed.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Simulation as an Aid in Model Building
Authors: Rich R. P.
Published: November 2008

An example drawn from fleet air defense illustrates the use of a very simple device which simulates the physical situation to be analyzed in the task of constructing a mathematical model of the situation. Such a simulator is also helpful in explaining the results of the analysis to the people for whom they are intended and in estimating the errors introduced by various computational approximations.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Financial Analysis in Johns-Manville
Authors: Green Stanley
Published: November 2008

This is a condensed version of the paper presented to the session on Accomplishments of Industrial Operations Research at the Washington meeting of the Society on November 19, 1954.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
A Statistical Guide for Accident Research, Illustrated by Application to Non-Air-Carrier Flying, 1949–51
Authors: Duncan Acheson J.
Published: November 2008

Because of lack of information on flying time it is difficult to appraise the statistics published by the C.A.B. on frequencies of accidents of aircraft used in non-air-carrier flying. Comparison of relative frequencies, however, may still be a useful guide in accident research. This paper develops a rating index for this purpose, illustrates its application to six important single-engine aircraft used in non-air-carrier flying in 1949-51, and discusses the difficulties and dangers in the use of the index when applied to aircraft accidents. The technique may be found equally useful in other fields of accident research.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
The Competence and Limitations of Scientific Method
Authors: Margenau Henry
Published: November 2008

Talk presented to the Johns Hopkins University Conference on Philosophy and Operations Research in Washington, November 2, 1954.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Mathematical Models for Freely-Flowing Highway Traffic
Authors: Newell G. F.
Published: November 2008

An attempt is made to construct models for the motion of cars on a highway in a manner analogous to the way one treats the motion of molecules in a gas as described by the kinetic theory of gases. In particular the comparison is made between a traffic flow at very low volumes and the motion in a rarefied gas. From this, we are led to expect that even a very crude model of the interaction between individual cars will give a quite reasonable description of the collective behavior of large groups of cars. Some simple estimates of the dependence of average velocity on density and distribution of cars in various lanes of a multilane highway based upon very crude models seem to confirm this expectation.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Letter to the Editor—Training for Operational Research at the University of Birmingham
Authors: Gander R. S.
Published: November 2008

No abstract available.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Stochastic Properties of Waiting Lines
Authors: Morse Philip M.
Published: November 2008

The stochastic properties of waiting lines may be analyzed by a two-stage process: first solving the time-dependent equations for the state probabilities and then utilising these transient solutions to obtain the auto-correlation function for queue length and the root-mean-square frequency spectrum of its fluctuations from mean length. The procedure is worked out in detail for the one-channel, exponential service facility with Poisson arrivals, and the basic solutions for the m-channel exponential service case are given. The analysis indicates that the transient behavior of the queue length n(t) may be measured by a “relaxation time,” the mean time any deviation of n(t) away from its mean value L takes to return (1/e) of the way back to L. This relaxation time increases as (1 − ρ)−2 as the utilization factor ρ approaches unity, whereas the mean length L increases as (1 − ρ)−1. In other words, as saturation of the facility is approached, the mean length of line increases; but, what is often more detrimental, the length of time for the line to return to average, once it diverges from average, increases even more markedly.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Road Safety and Traffic Research in Great Britain
Authors: Glanville W. H.
Published: November 2008

Talk presented to the Informal Seminar on Operations Research, The Johns Hopkins University, November 3, 1954.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Production Scheduling for an Arbitrary Number of Periods Given the Sales Forecast in the form of a Probability Distribution
Authors: Dannerstedt Gunnar
Published: November 2008

In this paper a mathematical model is presented for solving an optimum production scheduling problem. The optimum program is not dependent on the sale price as long as the production is forced to fulfill all the sales orders. The sales forecast is given in the form of a probability distribution for a number of periods. The costs consist of ordinary production costs, overtime production costs, and costs for carrying inventory. The importance of a unique policy for the calculation of the program is pointed out. Three different policies have been treated (1) scheduling for one period each time, (2) scheduling over two periods every second period, and (3) scheduling over as many periods as the enterprise is expected to last. The three different policies give different optimal programs. A numerical example has been carried out analytically where the differences are shown. Policy (1) above gives the lowest cost because all information about the inventories is known at the beginning of each of the periods.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Production and Inventory Control in a Chemical Process
Authors: Ackoff Russell L.
Published: November 2008

A great deal of research effort has been directed towards the construction of mathematical models for representing the cost of production in terms of pertinent variable factors. But having the model does not guarantee that it is economical, or even feasible, to use it for control purposes. This paper describes how a model was constructed for a complex chemical process, and why the use of the model was abandoned in favor of a simple operating scheduling rule.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Letter to the Editor—Some Thoughts on Operations Research on Municipal Operations
Authors: Horvath William J.
Published: November 2008

The rapid expansion in the use of mathematical methods of inventory control and production scheduling brought about in the last few years through the efforts of an active group of operations analysts and econometricians has led me to reflect on the forces that determine the directions in which new developments and new ideas such as operations research are channeled.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Letter to the Editor—Social Implications of Operations Research
Authors: Cowan Thomas A.
Published: November 2008

No abstract available.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Letter to the Editor—“Such Solutions are Very Little Solved”
Authors: Charnes A. , Cooper W. W.
Published: November 2008

The May, 1955, issue of JORSA carried two articles which seem to call for comment—one, a serious article by Bertram Klein entitled “Direct Use of Extremal Principles in Solving Certain Optimizing Problems Involving Inequalities” and two, a short, humorous one by Paul Gunther entitled “Use of Linear Programming in Capital Budgeting.” We believe that readers of JORSA will be well advised to treat the humorous article seriously and the serious article humorously.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
An Analog Solution of Programming Problems
Authors: Ablow C.M. , Brigham Georges
Published: November 2008

A simple, fast, and accurate method for solving (static) programming problems is presented. The method is particularly well adapted to electronic analog computers. The problem is interpreted as the asymptotic solution of a problem in the dynamics of a massless particle. The “particle” is considered to move in n-space away from those regions forbidden by the constraints of the problem and toward optimization of the criterion function. Constraint or criterion functions need not be linear but merely expressible with available computer components. The speed with which a solution is attained is under the operator's control.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
On a Congestion Problem in an Aircraft Factory
Authors: Brigham Georges
Published: November 2008

This is a study of the optimum number of clerks to be placed behind service counters. It involves queuing theory and was solved in two parts: First, we considered the counter from the customers' side, the “obverse” queue. Observational data showed that arrivals at the counter occur at random, the order of serving was random, and the distribution of the service times was exponential, so that Erlang's “C” formula for the probability that a customer has to wait applied. A formula is derived and graphed that shows the optimum number of clerks to be used behind the counter and the over-all minimum cost caused by waiting on the part of the customers and the clerks as a function of the queue input and the ratio of the cost of the customers' time to that of the clerks'. Second, the queue from the clerks' side was considered, that is, from the “reverse” queue. Clerks' time spent waiting for customers to appear is not altogether lost, if they can do work behind the counter. What happens to the clerks is governed by the characteristics of the “obverse” queue. From that is derived the probability distribution of the clerks' waiting time, considering the clerks to form a queue, as customers do. With this we calculate the saving in clerks' time that can be effected subject to the limitations of the shortest free period and the total length of time that can be used productively. This saving can then be subtracted from the cost computed in the first part of the study. The results obtained are applicable to any queuing operation which has the same characteristics.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
An Appreciation of Systems Analysis
Authors: Hitch Charles
Published: November 2008

Military systems analysis is an extension of operations-research techniques of World War II to problems of broader context and longer range—e.g., force composition and development as well as operations decisions. Greater complexity is inevitable as we attempt analyses to aid decisions affecting more distant time periods: growth in number of relevant variables, compounding of uncertainties; increased importance of enemy reactions; complications of time phasing, the need for a broader concept of criteria Techniques available to the systems analyst for dealing with these complexities are less than satisfactory. “Factoring” is inevitable. All routine or mechanistic approaches are deficient; e.g., expected value and minimax criteria. Design and criteria problems are of dominant importance. The systems analyst may have to be content with better rather than optimal solutions, or with devising and costing sensible methods of hedging; or merely with discovering critical sensitivities. He has an important role as inventor of systems. The difficulties of systems analysis are rooted in the nature of the military problems. Other methods—e.g, piecemeal analysis or intuition—do not escape them and have limitations of their own. Military systems analysis provides a framework for combining the knowledge of experts in many fields to reach solutions which transcend any individual expert's judgment.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Expectancy of Multiple Vehicular Breakdowns in a Tunnel
Authors: Edie Leslie C.
Published: November 2008

One of the principal operating problems at vehicular tunnels is that of traffic stoppages resulting from disabled vehicles. These vehicles break down for such various reasons as flat tires, overheating, no gasoline, and mechanical failures. The stoppages are particularly troublesome in peak traffic periods when the full capacity of the tunnel may be badly needed. Subaqueous tunnels consist of two-lane tubes, so that a stoppage in one lane immediately reduces the capacity of the tube affected by one-half. Actually, the reduction in capacity is even greater than one-half, since the movement of traffic in the unstopped lane is reduced by the operations necessary to remove the disabled vehicle.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Letter to the Editor—A Suggestion for Programming ORSA Meetings
Authors: Hoeber Francis P.
Published: November 2008

No abstract available.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Linear-Time Algorithms for Scheduling on Parallel Processors
Authors: Monma Clyde L.
Published: November 2008

Linear-time algorithms are presented for several problems of scheduling n equal-length tasks on m identical parallel processors subject to precedence constraints. This improves upon previous time bounds for the maximum lateness problem with treelike precedence constraints, the number-of-late-tasks problem without precedence constraints, and the one machine maximum lateness problem with general precedence constraints.
On Scheduling Independent Tasks with Restricted Execution Times
Authors: Leung Joseph Y.-T.
Published: November 2008

We consider the problem of nonpreemptively scheduling n independent tasks on m identical and parallel machines with the objective of minimizing the overall finishing time. The problem has been shown to be NP-complete in the strong sense and hence there probably will not be any pseudopolynomial time algorithm for solving this problem. We show, however, that if the execution times are restricted to a fixed number, say k, of different values, then it can be solved in polynomial time. Our algorithm can be implemented to run in time 0(log2p * log2m * n2(k−1)) and space 0(log2m * nk−1) in the worst case, where p is the largest execution time.
Technical Note—A Limit Theorem on Subintervals of Interrenewal Times
Authors: Green Linda
Published: November 2008

Consider a renewal process {Xn, n ≥ 1} for which there is defined an associated sequence of independent and identically distributed random variables {Bn, n ≥ 1} such that Bn is the length of a subinterval of Xn. We show that when attention is restricted only to B-intervals, the asymptotic joint distribution of the residual life and total life of a B-interval is that of a renewal process generated by {Bn, n ≥ 1}.
Optimal Sizing of Records when Divided Messages Can Be Stored in Records of Different Sizes
Authors: Erickson Ranel E. , Halfin Shlomo , Luss Hanan
Published: November 2008

In many computer applications, messages of various lengths need to be stored efficiently. We examine the problem in which a fixed number of record lengths can be used to store messages. Whenever a message arrives it is stored in the smallest possible record that can contain the message. If the message length exceeds the largest record length, the message is divided into segments whose lengths are equal to the largest record length except for the final segment which may be smaller. Each segment is then stored in the smallest possible record. Furthermore, each record is accompanied by a header that contains overhead information. Using a nonlinear programming approach, an efficient algorithm is developed that finds the record lengths which minimize the expected space used to store a message. Numerical examples are presented and compared to those obtained in a previous work in which it was assumed that divided messages are stored in several records all of the same length.
A Mixed Delay Dependent Queue Discipline
Authors: Kanet John J.
Published: November 2008

Previous research on delay-dependent priority queues is generalized to the case of general independent service times and where the priority of classes of units is permitted to increase or decay linearly with time. An expression for expected class waiting time for such systems is provided.
Technical Note—Complementary Slackness Theorem in Multiple Objective Linear Programming
Authors: Park Soondal
Published: November 2008

A complementary slackness theorem in multiple objective linear programming (MOLP) is proved. MOLP problems may have many efficient solutions, and the objective values of the solutions may not be equal to those of efficient solutions of their dual problems. We show that the necessary and sufficient condition for existence of a pair of primal and dual efficient solutions with equal objective values is as follows if a variable in the primal problem is positive, then the corresponding relation in the dual is equality, and if a relation in the dual problem is not equality, then the corresponding variable in the primal must be zero.
Decision Aid Development for Use in Ambulatory Health Care Settings
Authors: White Chelsea C. , Wilson Edward C. , Weaver Alfred C.
Published: November 2008

An approach is presented using interactive microcomputers for the development of diagnostic decision aids applicable to some complaints encountered in ambulatory care. The central feature of the descriptive phase of the approach is the use of the underlying (and perhaps dynamic) state of patient health. The central feature of the prescriptive phase of the approach is quick, simple assessment which produces a set of nondominated diagnostic tests, the selection of which is biased by the subjectively determined disease(s) that the diagnostician wishes to rule out or confirm. We present an application of the approach to the complaint, “diarrhea of recent onset in adults,” discuss the hardware/software implementation, and summarize preliminary evaluation results.
Explicit Steady-State Solutions to Some Elementary Queueing Models
Authors: Neuts Marcel F.
Published: November 2008

Several simple queueing models, commonly used as textbook examples, have explicit steady-state solutions, which to date have escaped notice. These solutions are easily computable. In addition to their didactic interest, the results presented here are also useful in the analysis of more complex queueing models.
Linear Estimators for a Class of Stationary Queueing Processes
Authors: Halfin Shlomo
Published: November 2008

We find the minimum-variance linear estimator for the expected value of a stationary stochastic process, observed over a finite time interval, whose covariance function is a sum of decaying exponentials. Such processes and estimators include many of the common measurements on Markovian queueing systems, such as the number of busy servers, all servers busy, number in queue, etc. We derive an explicit form for the best linear estimator, and investigate its properties. Next, we compare it to the standard estimator which assigns equal weights to all the observations, and show that asymptotically both behave in the same way. We conclude that in many practical cases, using the optimal weights will reduce slightly the estimator's variance.
Bounding the Reliability of Multistate Systems
Authors: Butler David A.
Published: November 2008

Determining the exact reliability of a complex system can involve extremely large amounts of computation. This paper develops a number of upper and lower bounds for the reliability of multistate systems, that is, systems for which each component may exist in one of a finite number of states. These bounds are based on the notions of minimal paths and minimal cuts and are far more easily computed than the exact system reliability. To further reduce the computations required and to obtain sharper bounds, a modular-decomposition-based bound is developed for multistate systems.
Detecting Initialization Bias in Simulation Output
Authors: Schruben Lee W.
Published: November 2008

A general approach to testing for initialization bias in the mean of a simulation output series is presented. The output is transformed into a standardized test sequence that can be contrasted with a known limiting stochastic process. This transformation requires very little computation and the asymptotic theory is applicable to a wide variety of simulations. An initialization bias test is developed and several examples of its application are presented.
Feature Article—Operations Research for Agricultural Pest Management
Authors: Feldman Richard M. , Curry Guy L.
Published: November 2008

It is increasingly important to maximize the productivity of our agricultural land. As concern for efficient food and fiber production increases, the importance of the application of operations research to agricultural problems increases. During the past decade, there has been much effort to combine mathematics and agriculture. This paper presents the role that operations research has played in integrated pest management for the agricultural industry. An effort is made to present the state-of-the-art in biological modeling for agriculture pest management and to provide an understanding of the type of mathematical techniques utilized.
Time-Inhomogenous Bulk Server Queue in Discrete Time: A Transportation Type Problem
Authors: Alfa Attahiru Sule
Published: November 2008

This paper studies the queue length distributions of a discrete time bulk server queue with time-inhomogenous compound Poisson input in which service is provided in time-inhomogenous batches and the interarrival times of the server have a general distribution. We assume that the service epochs form a renewal process. This sort of queue occurs during peak periods at intermediate bus stops, where passengers are waiting to catch a bus. In the queueing literature, this problem is known as a transportation type problem. The joint distribution of the number of customers waiting at any epoch and the remaining time before the next arrival of the server is obtained. The results are then extended to cover the case in which the waiting space is limited.
Setting Standards for Offshore Oil Discharges: A Regulatory Decision Analysis
Authors: von Winterfeldt Detlof
Published: November 2008

Offshore oil production platforms continually discharge oily water into the surrounding marine environment. To reduce the risk of these discharges, emission standards are set on the oil concentration in the effluent. This paper describes a decision analytic model for aiding regulators and platform operators in the standard setting process. The model combines three submodules: a regulator model, an operator model, and an impact model. The regulator model is a simple additive value function to evaluate different standards in terms of political objectives. The operator model is an expected utility model that determines optimal oily water treatment based on the standard set by the regulator, penalties for violating the standard, and equipment performance. The impact model simply uses random pollution levels, conditional on the standard and operator's decision, as a proxy for the effects on the marine environment. Given a particular standard, the model allows calculation of utilities or expected utilities for the regulator, the operator, and for environmental impact. An application of the model to setting discharge standards for North Sea production platforms identified several dominated standards. Non-dominated standards clustered around cutoff points at which the operator switched from inferior to superior treatment. These cutoff points were, in turn, very sensitive to treatment equipment uncertainty, and the regulator's monitoring and inspection procedures. In contrast, the analysis found cutoff points to be insensitive to penalties imposed by the regulator or to the risk attitude of the operator.
A Hybrid Decomposition Method for Integrating Coal Supply and Demand Models
Authors: Shapiro Jeremy F. , White David E.
Published: November 2008

A number of large scale models have been proposed and implemented in recent years to study the anticipated expansion of coal production and utilization in the United States. This paper reports on the application of mathematical programming decomposition methods to the constructive integration and optimization of these models. In particular, it was found that an implemented hybrid decomposition approach, part resource directed and part price directed, exhibited fast convergence to an optimal solution.
A Multiserver Queue with Thresholds for the Acceptance of Customers into Service
Authors: Neuts Marcel F. , Nadarajan R.
Published: November 2008

A queue with Poisson arrivals is served by N identical exponential servers. When a server becomes free, a group of customers of size at most b can be served. The server is not allowed to process a group of size less than a, 1 ≤ a ≤ b. The actual size of each group served depends on the number of waiting customers. The queue is studied as a Markov process. In the stable case, the stationary probability vector of this process has a simple, readily computable form. Using this form, the stationary waiting time distribution, which is analytically intractable, may be expressed in an algorithmically useful form. Several questions, related to the optimal design of such a service system, may be algorithmically investigated. This model serves to illustrate the advantages of the algorithmic approach. The design criteria are not analytically tractable in general.
Generalized Network Problems Yielding Totally Balanced Games
Authors: Kalai Ehud , Zemel Eitan
Published: November 2008

A class of multiperson mathematical optimization problems is considered and is shown to generate cooperative games with nonempty cores. The class includes, but is not restricted to, numerous versions of network flow problems. It was shown by Owen that for games generated by linear programming optimization problems, optimal dual solutions correspond to points in the core. We identify a special class of network flow problems for which the converse is true, i.e., every point in the core corresponds to an optimal dual solution.
An Alternative Method for Hospital Partition Determination Using Hierarchical Cluster Analysis
Authors: Klastorin T. D.
Published: November 2008

The classification of short-term hospitals into homogeneous groups has become an integral part of many systems designed to abate continuing cost inflation in the hospital industry. This paper describes one approach which was developed to identify homogeneous groups of short-term hospitals. The approach, based on hierarchical cluster analysis, defines an objective measure (called expected distinctiveness) to evaluate any group of hospitals identified by a hierarchical grouping structure or dendrogram. Using this measure, an efficient algorithm is developed which finds the hospital partition from the identified groups which maximizes total expected distinctiveness. A numerical example illustrates the application and extensions.