bluuebunny/crossref_metadata_2025 huggingface dataset:
Letter to the Editor—George Kimball, The Man
Authors: Lathrop John B.
Published: November 2008

Presented at the George Elbert Kimball Memorial Session, Thirty-third National Meeting, Operations Research Society of America, San Francisco, California, May 2, 1968.
Letter to the Editor—George E. Kimball
Authors: Morse Philip M.
Published: November 2008

Presented at the George Elbert Kimball Memorial Session, Thirty-third National Meeting, Operations Research Society of America, San Francisco, California, May 2, 1968.
Correction to “Queues with State-Dependent Stochastic Service Rates”
Authors: Harris Carl M.
Published: November 2008

Correction to the article Harris, Carl M. “Queues with State-Dependent Stochastic Service Rates,” Operations Research, Vol. 15, 117–130 (1967).
Monte Carlo Estimation of the Mean Queue Size in a Stationary GI/M/1 Queue
Authors: Daley D. J.
Published: November 2008

The serial correlation coefficients of queue sizes in a stationary GI/M/1 queue are studied. It is shown in particular that when the traffic intensity τ is near 1, estimation of the mean queue size from a simulation run of length N requires that N ≈ K(l − τ)−2 for some constant K in order that the sample means over a range of τ should have approximately the same coefficient of variation.
Erratum
Authors: Fishman George S.
Published: November 2008

Correction for the author's paper “The Allocation of Computer Time in Comparing Simulation Experiments,” Operations Research, Vol. 16, 280–295 (1968).
Adaptive Diagnosis of Faulty Systems
Authors: Chu Wesley W.
Published: November 2008

A model is developed for diagnosis of faulty systems when symptoms are observable. The model considers the probabilities of various malfunctions conditioned on the observable symptom, pij (the probability of having the ith malfunction when observing the jth symptom), and the costs of testing various malfunctions. In practice, the exact values of these parameters are very difficult to obtain; under this condition, adaptive techniques can be used to improve our knowledge of these unknown parameters from results of past diagnoses (leaning observations). When the learning observations used to improve the knowledge of pij are from the successful diagnosis (in which the malfunction was found), then the optimal adaptive diagnostic procedure is defined as the one that yields minimum expected mean diagnostic cost based on the present state of knowledge of pij. The necessary and sufficient conditions satisfied by such a procedure are derived. The value of learning observations is the difference in the expected cost of the diagnostic procedure with and without learning observation data. A method for computing this value is presented.
Use of Geometric Programming to Maximize Reliability Achieved by Redundancy
Authors: Federowicz A. J. , Mazumdar M.
Published: November 2008

This paper considers the problem of optimum allocation of redundant elements in a simple series sytem (maximizing system reliability subject to several linear cost constraints). Under the approximation that the components of the redundancy vector can be treated as continuous variables, the paper formulates this optimization problem as a geometric programming problem, describes techniques for obtaining numerical solutions in general, and obtains asymptotic closed-form solutions. A standard numerical example is used to illustrate that the asymptotic solution, when suitably rounded, compares favorably with the discrete optimal solution.
Closed Finite Queuing Networks with Time Lags
Authors: Posner M. , Bernholtz B.
Published: November 2008

Consider a closed finite queuing system in which m units move among stations 1, 2, …, N (N ≧ 1). A unit that completes service at station i moves to station j (i, j = 1, 2, …, N) with probability ej∣i (∑j = Nj =1ej∣i=1, i = 1, 2, …, N) where it either commences service immediately if there is a server available, or queues to await service. The time taken for a unit to move from station i to station j is a random variable with distribution function Gi,j(⋯). At each station, the service times are independent and exponentially distributed, with the instantaneous service rate at a station being an arbitrary function of the number of units at that station. The positions of the units enroute between stations, measured in time units, are introduced as supplementary variables yielding a Markov process with states having a combination of discrete and continuous components. The integro-differential difference equations for the state variables are derived, and the steady-state solution is determined. The marginal joint distribution for the number of units at each station is found, and shown to depend, not on the distributions of the time lags, but rather on some linear combination of the means of the time lag distributions. An approximate technique is outlined for determining the absolute probability distribution of the number of units at a station, and some of the limitations of this method are discussed.
Bounds on the Optimal Operating Policy for a Class of Single-Server Queues
Authors: Heyman Daniel P. , Marshall Kneale T.
Published: November 2008

We consider the economic behavior of a single-channel queuing system operating with the following cost structure: a server start-up cost, a server shut-down cost, a cost per unit time when the server is turned off, a cost per unit time when the server is turned on, and a holding cost per unit time spent in the system for each customer. For the undiscounted, infinite-horizon problem, bounds are obtained for the cost rate and optimal policy when the interarrival time distribution is a member of the class of increasing-failure-rate distributions. Some of the bounds hold for all interarrival-time distributions.
An Explicit Solution of a Special Class of Linear Programming Problems
Authors: Ben-Israel A. , Charnes A.
Published: November 2008

The linear programs considered here are of the form: [Formula: see text] where A is of full row rank, and (LP) is feasible with bounded optimal solutions. The main result is an explicit representation of the general optimal solution of (LP) in terms of a generalized inverse of A. This explicit solution of (LP)—explicit in the sense that A−1b is an explicit solution of Ax = b—has obvious theoretical (and possibly computational) advantages over the well-known iterative methods of linear programming. The results are illustrated by a simple example, and extensions to general linear programs are discussed.
Models for a Save-Discard Decision
Authors: Rothkopf M. H. , Fromovitz S.
Published: November 2008

This paper presents models for making an optimal save-discard decision under a variety of assumptions. The motivating problem involves a bulk commodity that comes in a rented container.
Optimal Simultaneous Search for the Maximum by the Principle of Statistical Information
Authors: Heymann Michael
Published: November 2008

This paper investigates the problem of estimating an optimal interval containing the location of the maximum of a unimodal function by simultaneous experimentation for the case when an arbitrary probability density function for the distribution of the maximum is given. The payoff of the estimation is taken to be the “statistical information” gained by the search. For an even number of experiments, the optimal strategy selects an interval estimate, containing the maximum point, for which the maximal a priori probability of containing this maximum is minimized. When the probability density is uniform, the optimal strategy minimizes the maximal length of the interval estimate. For an odd number of experiments, an unsymmetric search pattern results.
Letter to the Editor—The End
Authors: Bonney William H.
Published: November 2008

In the face of the view that the probability is 1 of the human race eventually being destroyed by some environmental calamity, one may argue that increasing controls over the environment may reduce this probability. But then the probability of eventual extinction via poor health is 1. However, one may argue that increasing controls over human health may reduce this probability. But then, under reasonable hypotheses (and regardless of accelerating environmental and health controls), extermination of the human race will be ensured (modulo probability 0) by a long run of consecutive human births of the same sex.
Letter to the Editor—Modification of the Primal-Dual Algorithm for Degenerate Problems
Authors: Greenberg Harold
Published: November 2008

This note presents a modification of the primal-dual algorithm for solving linear programs that speeds convergence in degenerate problems; it also gives some computational results.
Smoothing Start-Up and Shut-Down Costs in Sequential Production
Authors: Sobel Matthew J.
Published: November 2008

Zero or one unit is produced each period in this finite horizon deterministic nonstationary model of a production process in which units are produced one after another. Demand occurs at the end of each period, after which a holding cost applies to inventory. Other costs include a unit production cost if production is one, a start-up cost whenever production is one this period but zero last period, and a shut-down cost if production was one last period but is zero this period. It is shown that there is an optimal policy with a simple structure. Its exploitation reduces the determination of an optimal policy to finding a shortest route in an acyclic network with one more node than the horizon's length in periods.
Planning-Horizon Theorems for Knapsack and Renewal Problems with a Denumerable Number of Activities
Authors: Lippman Steven A.
Published: November 2008

This paper considers a class of knapsack and renewal problems and gives necessary conditions and sufficient conditions under which there is an (easily found) immediate decision that is optimal (with or without discounting) for all sufficiently large horizons.
Algorithms for the Simple Plant-Location Problem with Some Side Conditions
Authors: Spielberg Kurt
Published: November 2008

The algorithms of this paper belong to the direct-search or implicit-enumeration type. They compare to the recently proposed algorithm of Efroymson and Ray, as does the mixed integer algorithm proposed by C. E. Lemke and the author to that of Land and Doig. The general plan of procedure is expected to be equally valid for the capacitated plant-location problem and for transshipment problems with fixed charges; with some of the proposed devices more important for these difficult problems than for the simple plant location problem. Considerable computational experience has been accumulated and is discussed at some length. It suggests that additional work on the construction of “adaptive” programs, matching algorithm to data structure, is desirable.
Models of a Total Criminal Justice System
Authors: Blumstein Alfred , Larson Richard
Published: November 2008

The need to examine the total criminal justice system—police, prosecution, courts, and correction agencies—in an integrated way constitutes a central problem in improving law enforcement. Too, any such analysis must reflect the feedback into society of offenders released at various stages in the system. This paper formulates a model for the criminal justice system in one state; it depicts the flow of arrested persons through the system as a function of type of crime, and provides a basis for apportioning costs to system components and to types of crime. The model's feedback feature includes the probability of rearrest as a decreasing function of age and a crime-switch matrix reflecting the successive-crime distribution. The results from the model include a cost distribution by crime type, criminal-career costs, an examination of the courses of criminal careers, and estimates of the sensitivities of costs and offender flows within the system to changes in its controllable variables.
Optimal Strategies for Divestiture
Authors: Hayes R. H.
Published: November 2008

This paper examines a class of optional stopping problems in the context of the divestiture of an asset by a business or an individual. It first describes and analyzes a simple version of the problem, and then considers various generalizations, which are reduced to modified versions of the original problem. Next, it examines a heuristic procedure for obtaining approximate solutions, together with an analysis of the sensitivity of the criterion to a nonoptimal decision rule. Finally, it discusses the effect of a nonstationary environment on the divestiture strategy.
A Single-Server Priority Queuing System with General Holding Times, Poisson Input, and Reverse-Order-of-Arrival Queuing Discipline
Authors: Durr L.
Published: November 2008

This paper gives an explicit formula for the waiting-time distribution in a single-server system with general holding times subject to a Poisson input from any number of priority classes. In the general case, where the holding-time distributions of the demands in each priority case are different, the Laplace-Stieltjes transform and the moments of the distribution are found. The queue discipline is last-come first-served in each priority class. The cases of preemptive resume and nonpreemptive priorities are considered. It is shown that the variance of the waiting-time distribution (whatever the holding-time distribution) is greater than the corresponding variance when the queue discipline is first-come first-served.
An Appraisal of Some Shortest-Path Algorithms
Authors: Dreyfus Stuart E.
Published: November 2008

This paper treats five discrete shortest-path problems: (1) determining the shortest path between two specified nodes of a network; (2) determining the shortest paths between all pairs of nodes of a network; (3) determining the second, third, etc., shortest path; (4) determining the fastest path through a network with travel times depending on the departure time; and (5) finding the shortest path between specified endpoints that passes through specified intermediate nodes. Existing good algorithms are identified while some others are modified to yield efficient procedures. Also, certain misrepresentations and errors in the literature are demonstrated.
A Computationally Compact Sufficient Condition for Constrained Minima
Authors: Reklaitis G. , Wilde D. J.
Published: November 2008

This paper derives a second-order sufficient condition in differential form for a local minimum of the nonconvex nonlinear programming problem under the requirement of twice continuous differentiability. The condition is complementary to the differential form of the Kuhn-Tucker necessary conditions and involves the positive definiteness of a matrix of constrained second derivatives of rank and order equal to the number of variables having vanishing first constrained derivatives. By using linear information, the condition avoids consideration of the entire second-order portion of the Taylor expansion of the Lagrangian. An example illustrating the test is included.
Computer Solutions to Minimum-Cover Problems
Authors: Roth R.
Published: November 2008

A covering problem may be stated as follows: [Formula: see text] An algorithm has been programmed on the IBM 7094 for solving such problems. For a given problem, it generates a set of independent “locally-optimum” solutions. If p is the probability that any one solution is actually an optimum, then for n independently generated solutions we have a prob-babiiity of 1−(1 − p)n that an optimal solution appears in the set generated. Computational experience indicates that this approach yields good results for large problems (up to m · n ≦ 0.5 × 106).
A Multiserver Queue with Enforced Idle Times
Authors: Delbrouck L. E. N.
Published: November 2008

In this paper, exact, recursive, and asymptotic formulas' are derived for a queuing system in which access to the servers takes place at regular intervals. Steady-state results, already known, are extended and utilized to construct delay distributions that are adaptable to computer work.
Some Waiting-Time Distributions for Queues with Multiple Feedback and Priorities
Authors: Enns E. G.
Published: November 2008

This paper considers a single-server queue where incoming calls require exactly N services before leaving the system. Each service has a certain priority in relation to all other services, the server always accepting for service the call at the head of the nonempty queue with highest priority whenever he completes a service. Originating calls arrive according to a Poisson process and the service times for each type of service are independent random variables with the same arbitrary distribution. We show that for the N! possible permutations of the priorities, exactly 2(N−1) different waiting-time distributions will arise. The four waiting-time distributions obtained for N = 3 are discussed and an inequality established for the mean waiting times. For arbitrary N only the distributions giving rise to the minimum and maximum mean waiting times are discussed. It is possible, however, to calculate the waiting-time distribution for arbitrary N and any priority relation. The procedure is outlined by considering a specific example.
Letter to the Editor—Availability of Renewal Functions for Gamma and Weibull Distributions with Increasing Hazard Rate
Authors: Soland Richard M.
Published: November 2008

This note draws attention to the availability of tables of the principal renewal functions for cases in which the underlying lifetime distribution of the renewal process is gamma or Weibull with increasing hazard rate. The mathematical formulation is given, along with a description of the method of computation and an example illustrating the use of the tables.
On Assembly-Line Balancing Problems
Authors: Reiter Raymond
Published: November 2008

This paper considers three kinds of assembly-line disciplines: assembly lines without parallel subassemblies, lines with parallel subassemblies, and single-product assembly lines. To each such discipline there corresponds a line balancing problem. For the second and third disciplines, feasible (but not necessarily optimal) balances are characterized in terms of the directed graph defining the line. For any feasible balance, the minimum cycle time or assembly time can be computed easily from a certain graph, and a corresponding Gantt diagram determined. For the case of lines with parallel subassemblies, the paper gives a line initialization procedure such that, after initialization, the line can easily be balanced optimally.
A Mixed-Priority Queue with Applications to the Analysis of Real-Time Systems
Authors: Schrage Linus
Published: November 2008

Jobs arrive in a Poisson stream to a single processor. Associated with each job is a priority j = 1, 2, …. The processing time requested by a job can be partitioned into an arbitrary number of intervals of two types, (1) noninterruptible portions and (2) interruptible portions. Type 2 intervals can further be classified as preemptive-resume intervals and preemptive-repeat intervals that, in turn, can be further classified as being repeat with resampling or repeat without resampling. When a job is interrupted, a setup time (which is interruptible) must first be expended before the job can regain the processor. Steady-state moments and Laplace transforms are obtained.
Letter to the Editor—An Approach to Some Structured Linear Programming Problems
Authors: Bennett John M. , Green David R.
Published: November 2008

A recent paper by J. M. Bennett describes a decomposition algorithm for the class of linear programming problems commonly called “angular systems.” This note draws attention to a variant of the algorithm that is particularly suited to problems in which certain submatrices are sparse.
Letter to the Editor—A Critique of the Norman-White Dynamic Programming Approximation
Authors: Morton Thomas E.
Published: November 2008

This note points out that the Norman-White procedure utilizes the full apparatus of Bellman's value iteration, but stops after one iteration. This would seem wasteful unless either one iteration could be shown to give uniformly good results, or better stopping rules could not be found. A simple counterexample shows that the possible percentage cost error of the Norman-White procedure is unbounded. The note then discusses the excellent results of the approximation for their two examples, and mentions a stopping criterion for nondiscounted value iteration that is due to D. J. White himself.
Brains and Personality
Authors: Engel Joseph H.
Published: November 2008

Retiring Presidential Address given in the 35th National Meeting of the Society, Denver, Colorado, June 18, 1969.
A Model of Adaptive Team Decision
Authors: Ying Charles C.
Published: November 2008

This paper formulates a team-decision problem in the format of an adaptive approach to multiperiod decisions. It emphasizes attaining a conceptual clarity about the nature of team decision-making. As in the case of single-person adaptive decision processes, the optimal team-communication rule and team-decision rule for a given period generally depend on the number of periods remaining in an adaptive team-decision process.
Optimal Redundancy for Reliability in Series Systems
Authors: Ghare P. M. , Taylor R. E.
Published: November 2008

This paper considers the problem of determining the optimal number of redundant components in order to maximize the reliability of a series system subject to multiple resource restrictions. After formulating and solving an associated zero-one programming problem by a branch-and-bound procedure, the paper shows that the optimal solution to the associated problem is equivalent to the optimal solution for the optimal redundancy problem. Finally, the paper shows that this technique solves fairly large problems with multiple constraints without excessive storage-space requirements.
Probability Density of a Moving Particle
Authors: Washburn Alan
Published: November 2008

This paper studies a particular random tour (continuous random walk): A particle moves in two dimensions at constant speed by choosing successive travel directions that are independent and uniformly distributed between 0 and 2π, with the lengths of the steps between direction changes being independent, exponentially distributed, random variables. An analytic expression for the probability density of the particle's position after a time t is derived, and an application is made to a military situation where the “particle” is a target trying to escape being destroyed by an unseen enemy. The bulk of the paper is devoted to deriving the density function.
Constrained Nonlinear Optimization by Heuristic Programming
Authors: Paviani D. A. , Himmelblau D. M.
Published: November 2008

This paper develops a new algorithm for solving the general nonlinear programming problem that melds the flexible simplex search of Nelder and Mead with various additional rules to take care of equality and/or inequality constraints. The set of violated inequalities and equalities is lumped into one inequality constraint loosely satisfied during the early progress of the optimization and more closely satisfied during its final stages. To permit this type of search, the method sets up a special tolerance criterion, a function that does not depend on either the values of the objective function or the values of the constraints. The new algorithm has solved successfully a number of problems that have been proposed in the literature as test problems. Finally, to indicate the algorithm's capabilities, the paper describes an example composed of a linear objective function of twenty-four variables subject to fourteen nonlinear equalities and thirty inequalities.
A Force Effectiveness Model with Area Defense of Targets
Authors: Kooharian A. , Saber N. , Young H.
Published: November 2008

This paper describes an analytic method for computing the effectiveness of an ICBM force for the assured destruction mission, in which the missile force must attack a number of targets of different value, all protected by a fully preferential area defense. Some targets may also be protected by a terminal defense. The ICBM force is assumed to be composed of several types of re-entry vehicles that differ in lethality and in the numbers of area and terminal interceptors required for intercept. The model assumptions are offense-conservative in that the defense is credited with maximum information and capability. However, the offense allocation is optimum against the best cooperative use of the area and terminal defenses so that the computed force effectiveness is offense-enforceable. The paper derives the optimum employment of the missile force and the area defense, and proves that, in the presence of an area defense, the terminal interceptor stockpile should be allocated among terminally defended targets strictly in proportion to their value. Because of its simplicity, the inclusion of defense penetration parameters, the allowance for several types of re-entry vehicles, and its two levels of defense, the model is useful as a force-evaluation submodel in force-mix, force-defense, and re-entry-vehicle configuration studies.
Letter to the Editor—Educational Planning in Developing Countries—A Possible Role for Operations Research
Authors: Durstine Richard M. , Davis Russell G.
Published: November 2008

This letter suggests education in developing nations for possible applications of operations research and allied methods.
Letter to the Editor—Computational Experience with a Zero-One Programming Problem
Authors: Steinmann Horst , Schwinn Rolf
Published: November 2008

Previous papers by Fleischmann and by Lemke and Spielberg have reported computational experience with different algorithms for zero-one programming problems. This note supplements these papers by describing the experience with a special zero-one programming problem that arose from a mining context.
On a Class of Queuing Problems and Discrete Transforms
Authors: Rao S. Subba , Jaiswal N. K.
Published: November 2008

The main object of the paper is to demonstrate a method by which a number of problems arising in the study of impatient customers in queues can be solved. The main difficulty in analyzing such queuing systems is the presence of variable coefficients in the difference-differential equations describing the processes; the usual generating function method fails in such cases. When there is a finite number of states, it has been shown that at least formal solutions can be obtained through matrix algebra, which yields what are called “discrete transforms.” The results are explicitly given when the balking and reneging coefficients are linear in n. An alternative method in which the spectral resolution of matrices is used is also given for solution of the set of equations. In the special case of a M/G/1 queue with finite waiting room, both the methods fail (as the underlying matrix is in the Jordan form), and the solution is obtained by a simple manipulation of the underlying matrix. The methods presented here lend themselves readily to computer solutions. This paper demonstrates the generality of the basic M/G/1 model by relating it to problems arising in other branches of operations research, such as reliability theory, inventory control, etc. Finally, the methods used for the M/G/1 case are shown to hold for a similar class of problems in the GI/M/1 case. As very little work has been reported on impatient customer phenomena in GI/M/1, systems, possibly because of the difficulty in solving equations with variable coefficients, this method may prove to be useful.
Machine Sequencing Via Disjunctive Graphs: An Implicit Enumeration Algorithm
Authors: Balas Egon
Published: November 2008

One formulation of the machine sequencing problem is that of finding a mini-maximal path in a disjunctive graph. This paper describes an implicit enumeration procedure that solves the problem by generating a sequence of circuit-free graphs and solving a slightly amended critical-path problem for each graph in the sequence. Each new term of the sequence is generated from an earlier one by complementing one disjunctive arc. The search tree is drastically cut down by the fact that the only disjunctive arcs that have to be considered for being complemented are those on a critical path. An evaluation of these candidates is used to direct the search at each stage. The procedure can start with any feasible schedule (like the one actually used in production, or generated by some heuristics), and gradually improve it. Thus one can possibly stop short of the optimum, with a reasonably “good” feasible schedule. Storage requirements are limited to the data pertinent to the current node of the search tree.
A Problem in Optimal Search and Stop
Authors: Ross Sheldon M.
Published: November 2008

We are told that an object is hidden in one of m(m < ∞) boxes and we are given prior probabilities pi0 that the object is in the ith box. A search of box i costs ci and finds the object with probability α, if the object is in the box. Also, we suppose that a reward Ri is earned if the object is found in the ith box. A strategy is any rule for determining when to search, and, if so, which box. The major result is that an optimal strategy either searches a box with maximal value of αipi/ci or else it never searches such boxes. Also, if rewards are equal, then an optimal strategy either searches a box with maximal αipi/ci or else it stops.
A New Decomposition Procedure for Dynamic Programming
Authors: Wong Peter J.
Published: November 2008

This paper presents a new decomposition procedure that reduces the highspeed memory requirement and interpolations, associated with the dynamic programming algorithm. It shows that an nth-order system described by k coupled difference or differential equations can be treated as a kth-order system with respect to the high-speed memory requirement and interpolations in the dynamic programming procedure.
Simultaneous Success-Run Chains
Authors: Teugels Jozef L.
Published: November 2008

If every element from a source of identical particles has to perform a certain fixed success-run Markov chain with n + 2 states, and if the particles are put into the initial state one at a time, they act independently and reach the absorbing state n + 2 after n + 2 steps or they return to the source. This sequence of simultaneous success-run chains can be analysed by using a “basic” Markov chain with 2n different states that is studied in great detail. Among others, we derive the transition matrix and the stationary distribution. It further turns out that, for m ≧ n the basic Markov chain already behaves in a stationary way , so that it is easy to find the distribution of the number of absorbed particles at a certain instant, as well as the number of particles that return to the source. The proofs of the main theorems are based on mathematical induction and matrix methods.
Steady-State Solution of the Queuing System Eu/M/s with Batch Service
Authors: Love R. F.
Published: November 2008

This paper develops the steady-state solution for the queuing system with s parallel servers when arrivals are serviced in batches of size Q. The service time for all servers is exponentially distributed and the customer interarrival times are Erlangian of degree u.
Letter to the Editor—An Approach to Reducing the Computing Time for Dynamic Programming
Authors: Wong Peter J.
Published: November 2008

This note presents a procedure for reducing the computing time for dynamic programming when the optimal control function can be assumed to be piecewise smooth.
Making Short-Run Changes in Production when the Employment Level is Fixed
Authors: Sobel Matthew J.
Published: November 2008

In a factory with a given employment level, there are often opportunities to make adjustments to that level via overtime, the use of subcontractors, a curtailed work week, etc. These temporary adjustments are unlike those in production smoothing models where any change in the employment level during one period is carried over to the beginning of the next one. For a single product having stochastic demand, we characterize optimal production policies when the temporary adjustments have proportional costs. Other production costs in the model are proportional to the quantity produced and expected inventory holding and penalty costs are convex. The cases treated include nonstationary finite horizon stationary infinite horizon, discounted cost, average cost, and excess demand being either backlogged or lost. The infinite-horizon problems have optimal policies that depend on two parameters that can be computed with relatively small linear programming problems. The computations exploit the structure of the streamlined separable version of our Markovian decision problem.
Minimizing the Number of Operations in Certain Discrete-Variable Optimization Problems
Authors: Brioschi Francesco , Even Shimon
Published: November 2008

This paper deals with the solution to a discrete optimization problem by decomposition. It develops a criterion for ranking the decomposition procedures, discusses the properties of the optimal decompositions, and gives an algorithm for finding the best decomposition in the case of no storage limitation.
Solving Resource-Constrained Network Problems by Implicit Enumeration—Nonpreemptive Case
Authors: Schrage Linus
Published: November 2008

This paper considers a scheduling problem that has both precedence constraints (of a general form as in PERT-CPM problems) and resource constraints (of the form in the general job-shop scheduling problem), and gives an efficient enumerative procedure for generating all active schedules for this problem. Based on this enumerative scheme, the paper describes a branch-and-bound method for implicitly enumerating all schedules and determining the optimum; finally, it gives computational experience for the problem where the objective is minimizing the project makespan.
A Note on Quadratic Programming in Activation Analysis
Authors: Smith Lee H.
Published: November 2008

Various statistical techniques have been employed in “activation analysis” in order to provide a better means of estimating the amounts of various pure chemical elements contained in an unknown mixture. In particular, the method of least squares has been employed extensively. However, for the most part, the usual least squares applications in activation analysis have utilized the ordinary matrix model Y = Xβ + e, under the “error” assumptions (a) zero means, (b) variances proportional to Y, and (c) zero covariances. In addition to the fact that assumptions (b) and (c) may lead to erroneous results, the usual applications allow only point estimation, with no provision for confidence intervals and tests for model goodness of fit. Further, the usual applications fail to eliminate the drawback that negative coefficients are sometimes obtained. The present paper sets forth an iterative quadratic programming estimation procedure that not only eliminates the necessity for assumptions (b) and (c), but also alleviates the other above-mentioned difficulties.
Modular Design: An Application of Structured Geometric Programming
Authors: Passy U.
Published: November 2008

This paper considers an efficient algorithm for finding the optimal design of a module under a special set of circumstances that prevail in the design of a module for logistical applications. The method is based on primal-dual relations between generalized polynomial minimization and its quasi dual.
On the Explicit Solution of a Special Class of Linear Economic Models
Authors: Ben-Israel A. , Charnes A. , Hurter A. P. , Roberts P. D.
Published: November 2008

This paper derives explicit solutions for a class of linear (inequality) economic models heretofore treated by linear programming. These solutions are quite elementary and the decision criteria given are easily interpreted. The explicit solutions may involve the inversion of a single matrix, but even this is not necessary for the three applications in capital budgeting, production planning, and input-output analysis given in the paper.
Allocation of Sorties in Air Interdiction
Authors: Armitage John V.
Published: November 2008

This paper analyzes the problem of air interdiction in a simplified “hostile country” in which the flow of interdicted material is entirely unidirectional. The action is assumed to be constrained by a minimum tour-survival probability. Results are presented that permit the existence of feasible solutions of the constrained problem to be determined, that solve the problem completely in the unconstrained case, and that enable optimal solutions to be determined in the constrained case (but only when the probability-of-loss function p(x) is a step function).
Letter to the Editor—On the Merit of the Generalized Origin and Restarts in Implicit Enumeration
Authors: Salkin Harvey M.
Published: November 2008

This note discusses the concept of starting a (zero-one) tree search at an integer solution obtained from the associated linear program and restarting it at improved feasible solutions. Computational experience indicates that the length of the enumeration is inversely proportional to the closeness of the origin to the minimal integer vector.
Letter to the Editor—On Stochastic Linear Approximation Problems
Authors: Ben-Israel A. , Charnes A. , Kirby M. J. L.
Published: November 2008

This paper considers the extension of the linear approximation problem minimize ‖ϵ‖ subject to AX + ϵ = b to the case where the elements of b are independent random variables with known distributions. This extension is accomplished by the use of chance constraints. An analysis of this stochastic problem shows that the problem can be solved by some of the powerful computational methods of approximation theory.
Letter to the Editor—A Note on “Modular Design—A Special Case in Nonlinear Programming”
Authors: Evans David H.
Published: November 2008

A generalization of the modular design problem is explained and posed as an unsolved problem in nonlinear programming.
Science, Government, and Citizen Feedback
Authors: Stevens Chandler Harrison
Published: November 2008

This paper is based on the keynote address given at the 36th National Meeting of the Operations Research Society of America in Miami Beach, Florida; the theme of the meeting was “Operations Research in the Development of Emerging Countries.”
A Methodology to Compare Policies for Exploring the Solar System
Authors: Chamberlain Robert G. , Kingsland Louis
Published: November 2008

This paper describes procedures to process part of the information affecting decisions about unmanned exploration of the solar system. Since direct iteration between analysts and several levels of decision makers is, at best, a slow process, we have attempted to design the results of the analysis so that such iteration will not be necessary. In particular, we have avoided attempting to encode decision makers' judgments of probabilities or relative worths, relying instead on the technical judgments of technical experts in their areas of competence. Specifically, the contributions of proposed sequences of unmanned missions toward achieving the primary scientific objectives of exploring the solar system are determined. Consideration of the relative worths of these objectives, however, is left to the decision makers. Risks and uncertainties are explicitly considered, and results are depicted by probability contours. The utilization of resources—funding and manpower—is estimated and displayed. However, decisions cannot be made solely on the basis of the information processed with these procedures. Hence, mission sequences that the procedures indicate are less than optimal are retained. Since portions of the scientific objectives may be fulfilled (or preempted) by the space exploration programs of other nations, several foreign space programs are assumed as background to provide further insight into the wisdom of alternative decisions.
A Program of Astronomy Research on the Moon and its Logistics Implications
Authors: Freeman Raoul J. , Moore Roger C. , Schilling Gerhard F.
Published: November 2008

This study concerns itself with one aspect of possible post-Apollo space activity—a program of astronomical research on the moon that culminates in the establishment of a lunar observatory. A mathematical model is utilized to analyze the logistics implications of conducting such an astronomical research program. The nature of the research equipment needed for the accomplishment of the program is outlined. Superposition of this research program upon a basic, long-term, lunar-base operations plan tentatively indicates that it could be feasible to conduct such a program of research during the 1970's and 1980's well within the constraints imposed by the logistics of presently planned spacecraft, boosters, and launching facilities. In an earlier study, a mathematical model was described that can be used to evaluate various aspects of the logistics supply support of space operations. The present study utilizes this model to investigate the implications of superimposing a set of demanding scientific requirements on an existing space base support plan. First, a scenario is developed for a lunar astronomical research program in sufficient detail to fulfill the input requirements of the model. The resulting scientific requirements are described in terms of the equipment and instrumentation desired in a temporal sequence of gradually increasing demands that culminates in the establishment of an astronomical observatory on the moon. These requirements then are superimposed on a supply-support system that provides for the establishment and operation of a manned lunar base over an eight-year period. Detailed input parameters consider such aspects as capacities of launch vehicles and spacecraft, earliest and latest delivery times for various supply and scientific modules, etc.

The numerical results from two computer runs determine the necessary delivery schedules and provide an indication of the logistic cost of the postulated mission. For the specific astronomical example investigated, the results indicate that a lunar astronomical research program that culminates in the construction of a lunar-based observatory is logistically feasible. Further, such an observatory with sizable equipment could be established—without any unrealistic logistic requirements—within the next decades rather than during the next century.

However, these numerical results are of secondary significance at this time. The primary importance of the study is the demonstration of a technique that permits the quantitative comparison of the logistical aspects of alternative space missions where many interrelated input parameters can be examined in parametric fashion to determine the sensitivity of the system to each.
Queuing Analysis of Satellite Networks
Authors: El-Bardai M. T.
Published: November 2008

This paper models satellite communications systems by means of bipartite graphs. It assumes stochastic inputs and time delay is the factor of interest. The paper formulates the model and describes the routing and digital transmission schemes, assuming the network links to be synchronized. Messages may be transmitted only in the synchronized time slots, on a first-come first-served basis. The queuing problem is discussed for the single branch and for the satellite network cases, and approximate solutions are obtained for the case of satellites with finite memories.
A Continuation of Delay-Dependent Queue Disciplines
Authors: Hsu Jiunn
Published: November 2008

Kleinrock has studied linearly time-dependent queue disciplines with a set of positive variable parameters. This paper continues his work by deriving a result for a delay-dependent priority system in which a unit's priority is decreased from zero linearly with time in proportion to a negative rate assigned to the unit's group. The two queuing structures provide the system designers the same number of degrees of freedom.
A Statistical Analysis of Aircraft Maintenance Costs
Authors: Gilster Herman L.
Published: November 2008

This paper outlines the merits of the recursive regression model in analyzing aircraft-failure and manhour-cost data. The parameters of this model are estimated from maintenance data generated by the entire Boeing B-52 fleet during the period August 1965 to August 1966. Failure rates and manhours of repair are found to be a significant function of the calendar age of the aircraft, the length of the missions flown, the time spent in low-altitude flight, and the technological developments in newer aircraft. The estimated parameters are used to develop a marginal cost analysis that can be used by the decision maker in evaluating his maintenance operation. Although the paper is based on a specific military operation, the method outlined can be used to determine maintenance costs for any large jet aircraft.
Moment Estimation in a Markov-Dependent Firing Distribution
Authors: Rustagi J. S. , Laitinen Richard
Published: November 2008

The probability distribution of a number of Bernoulli trials required to obtain a preassigned number of successes under Markovian dependence arises in the study of certain weapon systems. If the sequences of observations are completely known, the maximum likelihood estimates can be obtained easily for the parameters in the distribution. However, when only partial information is available on the observed sequences, other methods of estimation, such as the method of moments, are employed. This paper obtains moment estimates of the parameters in this distribution and studies some of their properties.
Measures of Health-System Effectiveness
Authors: Packer Arnold H. , Shellard Gordon D.
Published: November 2008

This note extends some recent work of Packer by developing an alternative set of measures for the effectiveness of a health system.
Work Measurement and the Radiologist
Authors: Drui Albert B.
Published: November 2008

Work-measurement techniques generally are based upon the objective categorization of work activity. Several troublesome characteristics arise when applying the concept to professional people: antagonisms may develop between the observer and the professional being observed, and the importance of the qualitative aspect of the activity may say that the reason for doing something is as important as the fact that it is being done. This paper describes a project where these issues were faced in a constructive way by using subjective appraisal on the part of the professional being observed without unduly jeopardizing the principles of systematic scientific investigation.
Letter to the Editor—A Guide to the Application of Limit Theorems for Sequences of Stochastic Processes
Authors: Whitt Ward
Published: November 2008

This is a bibliography for applications in operations research of the theory of weak convergence for sequences of probability measures on function spaces. The reasons for using this theory are mentioned, the major issues are outlined, and appropriate sources of information are provided.
Letter to the Editor—Selecting Price Quotations for an Industrial Firm's Sale of Individual Contract Projects
Authors: Benson Purnell H.
Published: November 2008

Finns in contract work have data available from their bidding experience that are useful in making bids on future work for marketing their plant capacity. This note describes a procedure, based upon probability principles, for estimating the demand curve for the firm's output from its record of successes and failures in bidding for orders.