bluuebunny/crossref_metadata_2025 huggingface dataset:
Technical Note—Complementary Programming
Authors: Ibaraki Toshihide
Published: November 2008

A mathematical programming problem P: minimize z = dTx + eTu + fTv subject to Ax + Bu + Cv ≧ g, x, u, v ≧ 0, uTv = 0, is called a complementary programming (CP) problem. The condition uTv = 0 distinguishes CP problems from ordinary LP problems. A variety of nonlinear programming problems can be formulated in this form, including absolute-value programming problems, 0-1 mixed-integer-programming problems, quadratic-programming problems, and so forth. This paper proposes a branch-and-bound algorithm for CP problems and reports some computational results.
Technical Note—Exact Solution of the Fixed-Charge Transportation Problem
Authors: Gray Paul
Published: November 2008

In the fixed-charge transportation problem, a fixed charge is associated with each route that can be opened, in addition to the variable transportation cost proportional to the amount of goods shipped- This note presents an exact solution of this mixed integer programming problem by decomposing it into a master integer program and a series of transportation subprograms. To reduce the number of vertices that need to be examined, bounds are established on the maximum and minimum values of the total fixed cost, and feasibility conditions for the transportation problem are used extensively. Computational results show the method to be particularly suitable when fixed costs are large compared to variable costs. A composite algorithm based on Murty's and the author's results is proposed.
Decentralized Transshipment Networks
Authors: Ruefli Timothy W.
Published: November 2008

In the usual formulation of the transshipment problem it is assumed that a single decision-maker is dealing with a unified network of nodes and arcs and that supply and demand levels at each source are determined a priori. This paper develops a transshipment model in which subnetworks are controlled by a decentralized management level and supply levels at each source node are to be determined by a central manager.
Scheduling Bioproduction Harvest
Authors: Liang Tung , Huang Wen-yuan , Wang Jaw-Kai
Published: November 2008

Bioproduction is unique in its heterogeneous growth, unsteady product value, and production-rate-dependent harvesting cost structure. This paper develops a stochastic model for the harvesting process of a bioproduction, uses it to optimize a tropical-fruit-production harvesting operation, and conducts a sensitivity analysis with respect to the parameters in the model.
Production-Planning Algorithms for the Inventory-Overtime Tradeoff
Authors: Kunreuther Howard
Published: November 2008

This paper develops planning-horizon theorems and algorithms for determining optimal production in period 1 when there are linear costs associated with overtime and inventory, and demand is deterministic. If overtime in each period is unrestricted and no shortages are permitted, then it is easily shown that the firm will have to know future demand for at most the next k* periods, where k* is determined by the ratio of the wage differential between overtime and regular time to the per unit holding cost per period. Using the k* concept, the paper determines planning horizons when both storage and backlogging of demand are allowed. If overtime constraints are imposed, a planning algorithm is proposed that requires less information on future demand than a linear programming model. Economic implications of this approach for decision-making and information processing in firms are discussed.
Two Casualty-Estimation Problems Associated with Area Targets and the Circular Coverage Function
Authors: Read Campbell B.
Published: November 2008

The problems studied here may seem unrelated, although the analysis of each requires the use of the circular coverage function. The first considers an n-weapon attack on a circular area with uniform target density; the damage function is based on Hunter's (Hunter, J. J. 1967. An analytical technique for urban casualty estimation from multiple nuclear weapons. Opns. Res. 15 1096–1108.). The second considers a single-weapon attack on a target area with a symmetric normal density of targets, using a generalized “cookie-cutter” damage function. The damage functions used are believed to provide better fits to certain empirical damage curves than the cookie-cutter, and they have not previously been studied with the target models here. Algorithms are derived for calculating the expected number of casualties, or of targets damaged. Symmetric Gaussian aiming errors are assumed in both problems.
Technical Note—Parametric Solution of a Class of Nonconvex Programs
Authors: Hocking R. R. , Shepard R. L.
Published: November 2008

This note describes a parametric solution for the class of bicriterion mathematical programs identified by Geoffrion [Opns. Res. 15, 39–54 (1967)]. The algorithm described is based on a “parametric resource” optimization as opposed to the “parametric price” optimization suggested by Geoffrion. The relative merits of the two approaches are indicated.
Technical Note—System Simulation and Maximum Entropy
Authors: Chan Maynard M. W.
Published: November 2008

In the simulation of discrete systems, such as those using the popular GPSS simulator, the following problem is often encountered: What probability distribution should we employ for the value of a system parameter in the absence of any knowledge except its range? Based on the concept of entropy, this note provides justification for the use of several well-known distributions in various cases.
Technical Note—An Improved Combinatorial Algorithm for the Flowshop-Scheduling Problem
Authors: Gupta Jatinder N. D.
Published: November 2008

This paper examines the combinatorial approach to the solution of the n-job, M-machine flowshop scheduling problem under the assumptions outlined by Dudek and Teuton [Opns. Res. 12, 471–497 (1964)] and proposes an improved combinatorial algorithm that, according to our computational experience, is more efficient than the Smith-Dudek algorithm [Opns. Res. 15, 71–82 (1967), and 17, 756 (1969)].
Technical Note—On a Formula Dual to Erlang's Loss Formula
Authors: Cohen J. W.
Published: November 2008

For a service system with an infinite number of servers, Poisson arrivals, and negative exponentially distributed service times, this note considers various taboo probabilities, and derives an expression for the probability distribution of the maximum number y of customers simultaneously present during a busy cycle. It turns out that the expression for pr{y = n ∣ y ≧ n} is, in a certain sense, dual to Erlang's loss formula.
Operations Analysis in the United States Air Force
Authors: Brothers Leroy A.
Published: November 2008

Examples of operations analysis done for the United States Air Force are given, together with the author's conclusions as to conditions necessary for successful operations analysis, and an approach to a definition of the term.

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 Comparison of Order Structures for Automatic Digital Computers
Authors: Carter W. C. , Ellis M.
Published: November 2008

The choice of design parameters of automatic digital computers represents compromises among many factors. Some of these factors are programing convenience, speed of operation, ease of maintenance, efficiency of storage, cost of implementation, number precision, and machine capacity. The choice of particular values of a design parameter is simplified if the effect of the parameter on some of the indicated factors can be measured. A method is developed which results in a numerical measure of the effect of order types on speed and storage efficiency. This method and considerations of equipment cost are applied to a company payroll calculation in order to determine which of two specific order types is preferable. In addition to testing order type, some estimate of the equipment required to implement these order types is made. Only generally accepted features of the organization of automatic digital computers are assumed for this analysis. The example illustrating an application of this method is taken from actual experience and indicates the kind of information designers and potential customers should have in order to evaluate the performance of automatic digital computing equipment. Some of the detailed programing used in illustrating the method is included. Sample tabulations are also included and show how numerical measures of performance are calculated.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Priority Assignment in Waiting Line Problems
Authors: Cobham Alan
Published: November 2008

There are several commonly occurring situations in which the position of a unit or member of a waiting line is determined by a priority assigned to the unit rather than by its time of arrival in the line. An example is the line formed by messages awaiting transmission over a crowded communication channel in which urgent messages may take precedence over routine ones. With the passage of time a given unit may move forward in the line owing to the servicing of units at the front of the line or may move back owing to the arrival of units holding higher priorities. Though it does not provide a complete description of this process, the average elapsed time between the arrival in the line of a unit of a given priority and its admission to the facility for servicing is useful in evaluating the procedure by which priority assignments are made. Expressions for this quantity are derived for two cases—the single-channel system in which the unit servicing times are arbitrarily distributed (Eq. 3) and the multiple-channel system in which the servicing times are exponentially distributed (Eq. 6). In both cases it is assumed that arrivals occur at random.

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—Operations Research in a Period of Business Readjustment
Authors: Camp Glen D.
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—Opsearch in Germany
Authors: Knayer Manfred
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.
Traffic Delays at Toll Booths
Authors: Edie Leslie C.
Published: November 2008

The collection of vehicular tolls at Port Authority tunnels and bridges is one of the most important operations conducted by the police personnel. More than 250 traffic officers are utilized, and the payroll costs exceed a million dollars annually. In staffing its toll plazas the Port Authority attempts to handle traffic with a minimum number of toll collectors consistent with uniformly good service to the public and properly spaced relief periods for the toll collectors. This requires finding the level of traffic delays that gives the best compromise between the conflicting objectives of economy and service. In the past the number of toll collectors provided for operating a toll plaza was determined by judgment based on experience and a rule-of-thumb work standard which had not been related to service. Judgment was likewise used to allocate manpower and control the number of toll booths opened at any time. This method resulted in patron delays observed to vary from 2 to 50 sec. The tools of probability theory provide methods for dealing with the problem in quantitative terms. They enable determination of the relations between traffic volumes, number of toll booths, and grade of service. With this knowledge the optimum grade of service can be established in a logical manner and the number of toll booths required at any time of day can be specified in advance. Use of this method permitted savings in toll collection expenses and better service.

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 Verification of Lanchester's Law
Authors: Engel J. H.
Published: November 2008

The validity of Lanchester's equations is demonstrated in an actual combat situation where U.S. forces captured the island of Iwo Jima. The equations tested are dM/dt = P(t) − AN, and dN/dt = −BM, with t the time elapsed since the beginning of the engagement, measured in days; M(t), and N(t) the number of effective friendly and enemy troops, respectively; A and B the friendly and enemy combat loss rates, respectively, per opposing combatant; and P(t) the rate friendly troops enter combat. Information required for the verification is the number of friendly troops put ashore each day and the number of friendly casualties for each day of the engagement, knowledge that enemy troops are not reinforced or withdrawn, the number of enemy troops at the beginning and end of the engagement, and the time T at the end of the engagement. If the number of enemy troops at the beginning of the engagement is not known, but the time, T, when the enemy is destroyed is known, it is still possible to determine whether Lanchester's equations are valid. In the analysis of the capture of Iwo Jima, the equations were found to be applicable. The value of such analyses increases when repeated often enough to permit general conclusions to be drawn.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Optimum Preventative Sampling
Authors: Whittle P.
Published: November 2008

The situation envisaged is that in which a number of articles of varying value and liability to defect are sampled and inspected, the ultimate aim being not so much to detect defects as to discourage their arisal. General results are obtained (see “The General Equations”), of which the following specific result is typical, under certain circumstances the optimum sampling fraction for those articles having value vi is approximately [Formula: see text] Here F is the predetermined total sampling fraction, vG the geometric mean value of all articles, and C a coefficient measuring the deterrent effect of sampling on carelessness, etc. Under the same circumstances, the ratio of the expected total avoidable loss under optimum sampling to that under uniform sampling is approximately vG/vA, where vA is the arithmetic mean article value. The ratio vA/vG thus provides a measure of the advantage to be expected in using an optimum sampling scheme.

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—Simulation by Computation as an Operations Research Tool
Authors: Hurd Cuthbert C.
Published: November 2008

An object of operations research in business is to apply scientific methodology to the solution of management problems; in particular, the operations-research tool, simulation, in useful. In this paper the simulation employed in two engineering design problems is described, and it is shown that similar methods can be employed in two other management problems: estimation of costs and machine shop loading.

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—Railroad Executives' Seminar on Operations Research
Authors: Davidson Harold O.
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—Comment on the Theory of Value
Authors: Steinhardt Jacinto
Published: November 2008

Comment on “The Theory of Value and the Science of Decision—A Summary,” Jour. Op. Res. Soc. Am. 1, 103, 1953.

Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Observations on Operations Research
Authors: Hurni M. L.
Published: November 2008

If this meeting is typical, we will hear a number of fine papers on such specific methods as queuing theory, decision theory, search theory, linear programming, etc. I would predict there will also be many excellent case studies discussed. In view of this display of professional talent, it seems that what is reserved for me, is to discuss operations research from the viewpoint of an inquisitive potential client who is at the same time intrigued by what we claim and confused by what we seem to do.

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 Effect of Reliability of “Supervisory” Equipment on the Accuracy of a “Supervised” System
Authors: Boldyreff Alexander W.
Published: November 2008

This study deals with a basic system, the performance of which degenerates through random errors increasing with the square root of operating time. The probable circular error of this system can be made independent of the time by the addition to the system of supervisory equipment capable of periodic correction of the errors of the basic system. Assuming the supervisory equipment “fail safe” and subject to constant hazard type of failure, the performance of the supervised system is determined for various values of reliability of the supervisory equipment. It is shown that a great improvement in performance is possible even with unreliable supervision.

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 Family of Queuing Problems
Authors: Morse Philip M. , Garber H. N. , Ernst M. L.
Published: November 2008

Operational situations involving waiting lines differ from each other primarily in the number of service channels available and in the statistics of the service process. Other differences are possible, such as the occurrence of a non-Poisson arrival pattern or the imposition of priorities (A. Cobham, J. Opns. Res. Soc. Am. 2, 70 (1954).) but such differences are less frequent. Consequently it appears likely that a two-parameter family of queuing problems, one parameter being the number a of service channels and the other parameter specifying the statistics of the service process, would correspond to most of the waiting-line situations ordinarily encountered.

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—Logical Translation of English
Authors: Davidson Leon
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.
Cost-of-Research Index, 1920–1970
Authors: Milton Helen S.
Published: November 2008

The current study brings up through 1970 the cost-of-research index that was published in Operations Research 14, 977–991 (1966). This paper points out various economic aspects and effects of the R&D fluctuations between 1965 and 1970 within the framework of the index pattern for the twenty-year period 1950–1970. The objective of the index is to provide a measure of (l) the change in the cost of a technical man-year of research in the US, and (2) the change in the amount of research and development (R&D) effort in terms of technical man-years of effort applied to it as derived from total dollars spent on R&D. The index is a tool to be utilized in determining the rate of change in costs per technical man-year in R&D and for use in R&D planning and budgeting.
A Noniterative Algorithm for Tridiagonal Transportation Problems and Its Generalization
Authors: Lev Benjamin
Published: November 2008

Some transportation problems are such that, when origins and destinations are suitably indexed, the cost matrix contains elements along the main diagonal, a band above it, and a band below it, while the other elements of the cost matrix are infinite. We present here a procedure that yields optimal solution to such tridiagonal problems in n steps for an n-origin, n-destination problem. We also suggest a method for solving any other model that is “close” to a tridiagonal one by Bender's Algorithm. The algorithm presented here works by eliminating all off-diagonal variables in terms of the diagonal ones, and then specifying values for the diagonal variables. The extension with Bender's Algorithm involves solution of a sequence of tridiagonal models and small linear programming problems.
On Refinements of Some Duality Theorems in Linear Programming over Cones
Authors: Kortanek K. O. , Soyster A. L.
Published: November 2008

Recently Schechter (in a Lehigh University report) formulated two dual linear programming problems over closed convex cones in quite general spaces and showed that, if precisely one of the problems is feasible, then the feasible one has infinite value. In this paper we obtain a refinement by using asymptotic duality states as defined by Ben Israel-Charnes-Kortanek and their classification theorem [Bull. Am. Math. Soc. 74, 318–324 (1969) and 76, 426 (1970)]. The sharpened version shows that in general the feasible-infinite states of the dual problem-pair are not quite as symmetrical as, for example, in the special case of polyhedral cones. Similarly, a sharpened version of Duffin's Theorem 1 [H. W. Kuhn and A. W. Tucker (eds.) Linear Equalities and Related Systems. Princeton University Press, pp. 317–329, 1956] is also developed.
Technical Note—Strengthened Dantzig Cuts for Integer Programming
Authors: Rubin David S. , Graves Robert L.
Published: November 2008

In 1959, Dantzig proposed a particularly simple cut for integer programming. However, in 1963, Gomory and Hoffman showed that, in general, this cut does not provide a finite algorithm. In 1968, Bowman and Nemhauser showed that a slightly modified version of the Dantzig cut does provide a finite procedure. We show how this latter cut can be strengthened through the use of group-theoretic techniques.
Technical Note—A Note on Zero-One Integer and Concave Programming
Authors: Bowman V. Joseph , Glover Fred
Published: November 2008

It has been shown that the zero-one linear integer programming problem can be formulated as a minimization of a concave quadratic objective function subject to linear constraints. This note extends the concept to a broad class of concave objective functions.
On Scheduling the Delivery of Babies
Authors: Kabak Irwin W.
Published: November 2008

With the advent of elective induction of labor, the management of an obstetrical practice has assumed the problem of scheduling the delivery of babies. The problem can be thought of as a delay queuing system with a modified finite-source arrival pattern. This paper analyzes the case of a single server to determine the probability of interference (viz. the obstetrician must serve two or more patients simultaneously), solves the special case of “Poisson” arrivals and gamma (Erlangian) service times, and presents numerical values for these cases. An extension is presented wherein the probability of interference occurring within a finite time is analyzed.
Technical Note—Some Comments on Engel's “A Verification of Lanchester's Law”
Authors: Samz Robert W.
Published: November 2008

A recent reexamination of the combat data from the WWII battle for Iwo Jima has yielded some revisions of the data used in Engel's paper [Opns. Res. 2, 163–171 (1954)]. However, the revised data also fit Lanchester differential and difference equations closely, as Theil's inequality coefficient shows.
An Equilibrium Flow Model of a University Campus
Authors: Oliver Robert M. , Hopkins David S. P.
Published: November 2008

This paper develops a simple deterministic model that relates student admissions and enrollments to the final demand for educated students. It includes the effects of drop-out rates and student-teacher ratios upon student enrollments and faculty staffing levels. Certain technological requirements are assumed known and given. These, as well as the laws of flow conservation and the relations between equilibrium enrollment levels and average flow rates, are used to predict the effects of specific administrative policies and institutional controls at the campus level.
A Probabilistic Model for Optimal Project Scheduling
Authors: Rubinovitch Michael
Published: November 2008

This paper formulates a model for the scheduling and control of a multiphase project that consists of a given sequence of jobs to be completed by a specified due date. The duration of each job is the sum of a known fixed time and a random delay; and, while the former may be shortened within given limits, there is no control over the latter. The decision variables are the level of activity in each job and the starting time of the first in the sequence. An optimal decision policy for this model is obtained assuming a simple cost structure. It is shown that, if this policy is followed, a minimum a priori probability of meeting the due date is guaranteed.
Some Reliability Fault-Testing Models
Authors: Butterworth Richard
Published: November 2008

This paper presents several fault-testing models. Our system is composed of n components that either work or fail. The systems treated are the k-out-of-n type (k/n). This system works if and only if k or more of its components work, making the series (n/n) and parallel (1/n) systems special cases. Components can be individually tested and tests give perfect information. Each test has a time to complete it and testing procedures are judged by the expected cumulative testing time they require. In the first model, the components are assumed to function or fail independently of each other. A feasible test procedure must determine (as) if the system is working or has failed. This is solved for the series and parallel systems and, under a possibly restrictive hypothesis, for the general k/n system. In another model, the components are assumed to be nominally independent conditioned on the system being failed. Here a feasible test procedure must locate all failed components. This problem is solved for the general k/n system.
Expected Damaged Area for Stick and Triangular Pattern Bombing
Authors: Jaiswal N. K. , Sangal P. P.
Published: November 2008

Three bombs are to be dropped on a rectangular target either in a stick or in an equilateral triangular pattern. Assuming bombing and aiming errors to be normally distributed and the damage function of each bomb to follow a non-circular exponential square fall-off law, the expected damaged area in both the cases is determined.
Stochastic Duels with Damage
Authors: Nagabhushanam A. , Jain G. C.
Published: November 2008

This paper considers the duel between two contestants with unlimited ammunition supplies, each one firing at the other. It assumes that the damage resulting from a round of fire is measurable and has a probability distribution. The cumulative damage function depends both on time and on number of rounds fired. For given rates of fire, damage functions, and other parameters, the paper calculates the probabilities that a given side will win.
Two Measures for Describing Queue Behavior
Authors: Bhat U. Narayan
Published: November 2008

This paper defines two finite time measures that describe the transient behavior of queuing systems and investigates their convergence properties in some detail. These measures are: (i) a utilization factor that gives the fraction of time during which the system is expected to be busy, and (ii) an effectiveness factor that gives the ratio of the lengths of time during which the system is expected to be busy and idle, respectively. For the sake of convenience, these are expressed relative to their steady-state values. Tables are provided for these two measures in special cases.
Multilevel Bulk Service Queues
Authors: Bahary Emil , Kolesar Peter
Published: November 2008

This paper uses the imbedded-Markov-chain method to study bulk service queuing systems in which the server chooses the capacity and service mechanism depending on the number of customers waiting in line at the start of the service. It derives conditions under which the systems studied are ergodic and obtains the stationary state probability generating functions. A bilevel hysteretic bulk service system is studied in detail using numerical methods. A concept of system “scale” is introduced that permits the calculation of operating characteristics of large systems from those of small systems. This property is important because the computations for large systems are much more difficult, if not impossible, to perform. The characteristics studied are the expectation and variance of the queue size, the proportion of time each service level is used, and the transition rate between service levels.
Queuing with Two Servers Working in Shifts
Authors: Scott Meckinley
Published: November 2008

This note deals with the analysis of a single-counter queuing model operated by two servers. In any busy period, only one of the servers operates the service mechanism and, at its termination, the other server replaces him. In this manner, the two servers work alternately. Some generalizations of the model are discussed briefly.
The Infinite-Server Queue with Poisson Arrivals and Semi-Markovian Services
Authors: Neuts Marcel F. , Chen Shun-Zer
Published: November 2008

This paper considers the queue with an infinite number of servers with a Poisson arrival process and with semi-Markovian service times. It studies jointly the queue-length process and the type of the first customer to join the queue after t and obtains transient and asymptotic results that are matrix extensions of the corresponding results of the M/G/∞ queue. In particular, it proves that the limiting distribution of the queue-length process is Poisson.
Remark on a Service System with Mixed Input Streams
Authors: Ryba Teresa
Published: November 2008

In a paper published in Opns. Res. 14, 145–156 (1966) J. P. Young discusses multiple-channel queuing systems with exponential service-time distribution, no waiting space, and two parallel input streams (Poisson input mixed with an L-phase Erlang input). This note discusses the consequences of an additional assumption introduced by Young to obtain steady-state probabilities of having n channels occupied. Since the assumption is justified only for the pure Poisson input in the case of mixed input, the Erlang formula (4), proposed by Young, gives only an approximation to the exact probabilities.
Systems Problems in the City
Authors: Szanton Peter L.
Published: November 2008

An invited address presented at the Joint National Conference on Major Systems held at Anaheim, California, October 25–29, 1971, and sponsored jointly by the Operations Research Society of America and the Man and Cybernetics Group of the Institute of Electrical and Electronic Engineers.
The Application of Multifunction Stochastic Service Systems in Allocating Ambulances to an Urban Area
Authors: Hall William K.
Published: November 2008

Alternative policies for the allocation and distribution of ambulances are studied for the city of Detroit, Michigan. Data on emergency occurrence and service processes were collected and analyzed, and these data analyses are utilized to model the ambulance system as a multifunction stochastic service system with semi-Markov arrivals and state-dependent server selection. Numerical results are developed predicting the performance of both single function recovery systems and dual function police-ambulance systems under alternative operating policies.
Response Areas for Two Emergency Units
Authors: Carter Grace M. , Chaiken Jan M. , Ignall Edward
Published: November 2008

This paper gives a model in which two urban emergency service units (such as fire engines or ambulances) cooperate in responding to alarms or calls from the public in a specified region of a city. Given the home locations of the units and the spatial distribution of alarm rates, it is possible to specify which unit should respond to each alarm by defining a response area for each unit. The average response time to alarms and the workload of each unit are calculated as functions of the boundary that separates their response areas. The boundaries that minimize average response time and the ones that equalize workload are determined. Some boundaries can be dominated, in the sense that another boundary improves both workload balance and response time. The set of undominated boundaries is found.
A Method for Districting Among Facilities
Authors: Keeney Ralph L.
Published: November 2008

A problem shared by many municipal agencies and many large industries is: Given n service facilities whose locations have been set in a region, how should that region best be apportioned among the facilities if each facility is to have primary responsibility for service in one district of the region? This paper presents a simple and intuitive procedure for determining the boundaries of the service districts, using the criterion that each facility serves all points to which it is closest in either distance or travel time. The procedure is designed to be computed rapidly, either by hand or on a computer.
A Telephone-Access Biomedical Information Center
Authors: Rossi J. A. Dei , Mills G. F. , Sumner G. C.
Published: November 2008

This paper examines the costs of information centers using voice-grade telephone lines to provide access to recorded messages on subjects of interest to physicians. The methods developed are applicable to the analysis of any telephone-access information system. Telephone-line rental charges constitute the major portion of costs. Sufficient lines must be available so that no more than 5 percent of peak-usage calls will be blocked; the number of lines required is obtained from queuing theory. A break-even volume of calls is calculated from the rate structure, and the appropriate mix of flat-rate and metered-rate lines determined and costed. Also examined are the sensitivities of communication costs to errors in usage estimates, variations in mean service time, and changes in the peak-hour blocking criterion. Multiple-center configurations are also investigated. Although communication costs are generally lower than for a single center, the single center has the lowest total annual operating cost, due primarily to the higher personnel costs of multiple centers. The cost advantage of a single center is accentuated if equipment-investment costs are considered.
Maximal Flow with Gains through a Special Network
Authors: Jarvis John J. , Jezior Anthony M.
Published: November 2008

This paper uses the special structure at a (directed) acyclic network with positive gains to develop an extremely simple and powerful algorithm for maximal flow. Finiteness of the algorithm is achieved through a theorem characterizing basic solutions for this special network.
Solution of the Flowshop-Scheduling Problem with No Intermediate Queues
Authors: Wismer D. A.
Published: November 2008

This paper presents an algorithm that will minimize the total processing time for a particular case of the n-job, m-machine scheduling problem. In many industrial processes, jobs are processed by a given sequence of machines. Often, once the processing of a job commences, the job must proceed immediately from one machine to the next without encountering any delays en route. The machine sequence need not be the same for an jobs. Because of this processing constraint that prohibits intermediate queues, most normal scheduling techniques are not applicable. This paper obtains a solution to this constrained scheduling problem by modeling it as a traveling-salesman problem; known solution techniques can then be employed. The paper solves a sample problem and discusses computational considerations.
Optimal Operating Policies for the Finite-Source Queuing Process
Authors: Jaiswal N. K. , Simha P. S.
Published: November 2008

This paper evaluates the queue-length distribution, the busy-period density and other characteristics of the finite-source queuing process in which the server remains idle until a queue of n units is built up. It also determines values of n that optimize the net profits for discounted, as well as undiscounted, infinite-horizon models.
Errata
Authors: Layno Salvador B.
Published: November 2008

Errata to author's paper “A Model of the ABM-vs.-RV Engagement With Imperfect RV Discrimination,” Opns. Res. 19, 1502–1517 (1971).
A Model of a Traffic Jam Behind a Bottleneck
Authors: Brill Edward A.
Published: November 2008

This paper discusses a model for the stochastic motion of the slow-down points of cars behind a bottleneck. The model considered assumes cars to have nonzero length, and employs a simple “car-following-slowdown rale.” The case where “gaps” between cars form a stationary reversible sequence of random variables is discussed, and the main result consists of an explicit expression for the steady-state distribution of the physical length of the stream of cars behind the bottleneck when “gaps” are independent and identically distributed (iid) with exponential tail and atom at the origin. When this atom has zero mass (i.e., the gaps are iid exponential) it turns out that the result yields the steady-state distribution of waiting time in an M/D/1 queue and agrees with the known result. When this atom is nonzero, the main result in the queuing context yields the steady-state distribution of waiting time in an M′/D/1 queue, where M′ denotes an arrival stream with interarrival times being iid with exponential tail and atom at the origin.
A Problem in Bulk Service Scheduling
Authors: Nemhauser G. L. , Yu P. L.
Published: November 2008

Given the operating costs, usage function, and planning horizon of a bulk service system, say a common-carrier transportation system, the objective is to determine the number and the starting times of the services so that the total profit is maximized. For such problems, this paper studies the existence and computability of optimal schedules. It shows that an ϵ-optimal schedule can be found by a discrete optimization on a sufficiently fine grid. It then makes more specific assumptions regarding the dependence of usage on the schedule and presents a dynamic-programming algorithm for the discrete optimization. Finally, an analytic solution is given for a simple case.
Scheduling to Minimize the Variance of Holding Costs in Joint Production
Authors: Fairhurst J. H.
Published: November 2008

This paper considers the case of a product consisting of several components, each of which is batch manufactured. It assumes that the product demands occur singly, and that the components are manufactured in equal-batch quantities in a reorder level-batch quantity system. The paper is concerned with the optimal phasing of the components in order to minimize the variance of holding cost for the product. It shows that the optimal policy is independent of the order of sequencing of the components and is given when the phase lag between consecutive components in the cycle is equal to [(Ai + Aj)/∑all i Ai](q/2), where Ai, Aj are the unit values of the components, and q is the batch quantity. A specific example is included to illustrate the three-component case and the discrete practical solution for any number of components is indicated.
An Algorithm for Project (Job) Sequencing with Resource Constraints
Authors: Corenstein Samuel
Published: November 2008

This paper treats the problem of project (or machine) scheduling with resource constraints to achieve minimum total duration time as a disjunctive graph. The prospective advantage of this approach is the elimination of the need to consider individual time periods over the program horizon; a feasibility check determines whether the resource constraints can be met by any particular network representation of the project. The paper gives an algorithm that uses partial enumeration for what is essentially a mixed integer program. The algorithm employs a maximum-flow computation as a check for feasibility with respect to available resources.
Optimal Control Systems with Stochastic Boundary Conditions and State Equations
Authors: Baum Richard F.
Published: November 2008

We consider here control problems of optimization with stochastic boundary conditions that are obtained by allowing; boundary data and certain constraints to depend upon a random variable π = π(a), α ϵ I1π continuous over I1. We also allow the state equations to depend upon a random variable or a stochastic process η = η(t, b), b ϵ I2, with suitably smooth sample paths. We take for admissible controls measurable functions u = u(t) of t only with values in a compact control set U(t) ⊂ Em. Hence the admissible trajectories x = x(t, a, b) are stochastic processes, that is, for each t, x is a random variable over I = I1 × I2 with respect to a given probability measure P over I. We take as our cost functional Ek[t2, x(t2, a, b)] where E denotes expectation with respect to P. We state an existence theorem for such systems, and give necessary conditions that an optimal pair x0, u0 must satisfy. We also discuss applications of these results to various models in operations research.
Reliability Estimation in Life Testing in the Presence of an Outlier Observation
Authors: Sinha S. K.
Published: November 2008

The behavior of R̂t, the uniformly minimum variance unbiased estimator (umvne) of the reliability function for the one-parameter exponential family, is discussed when an outlier observation is present. Bounds of E(R̂t∣α) and MSE(R̂t∣α) have been obtained and a new estimator Rt* is proposed, where α reflects the “outlier effect on the scale” parameter. A “semi-Bayesian” approach is discussed when α is treated as a random variable with a Beta-type prior. A similar solution, when δ reflects the “outlier effect of the location” has been obtained.
Technical Note—A Scheduling Problem Involving Sequence Dependent Changeover Times
Authors: Lockett A. G. , Muhlemann A. P.
Published: November 2008

This note discusses a problem of scheduling jobs on a machine using various machine tools in which considerable changing of the tools is necessary, and the changeover time depends critically on the previous jobs. It derives a branch-and-bound algorithm, which has been shown to be computationally restrictive at the present time. Various heuristic methods have been tried and the computational results are very promising.
Technical Note—Markov Decision Processes with State-Information Lag
Authors: Brooks D. M. , Leondes C. T.
Published: November 2008

The Markov-decision-process formulation provides a method for selecting the optimal policy in a process where changes of state are Markovian, but assumes perfect information as to process state at each stage of the process. Where the available observations of the actual process state provide imperfect state information, the Markov-decision-process approach is applicable only if the observed state changes in a Markovian fashion. Although this is not true in the general case, it does apply in the important special case where information about the physical state becomes available after a delay of one transition or stage. This information-lag process can be analyzed as a Markov decision process. The degradation in gain, or expected return per unit time, from that of the perfect-information process provides a measure of the potential value of improving the information system.
A Partitioning Problem with Applications in Regional Design
Authors: Corley H. W. , Roberts S. D.
Published: November 2008

Many problems in two-dimensional location analysis can be formulated as one of optimally dividing a given region into n subregions with specified areas. Examples are problems involving districting, facility design, warehouse layout, and urban planning. This paper contains a study of such a partitioning problem. Theoretical results are presented for a problem of optimally partitioning a given set of points in k-dimensional Euclidean space into n subsets, where each subset has a specified Lebesgue measure. The existence of an optimal solution is established, and necessary and sufficient optimality conditions are proved. Models are then formulated in terms of this partitioning problem for specific districting and warehouse-layout problems.
Technical Note—Bounds for the Travelling-Salesman Problem
Authors: Christofides Nicos
Published: November 2008

This paper concerns finding a tight lower bound to the travelling-salesman problem, with the hope that all the different branch-and-bound algorithms for this problem can benefit from it. The bound is calculated by an iterative procedure with guaranteed convergence and is shown to require a computation time only about 9 per cent greater than the time required to solve an equivalent assignment problem. This new bound was tested on 14 sample problems and, on the average, found to be only 4.7 per cent below the optimum for symmetrical, and 3.8 per cent below the optimum for asymmetrical problems.
Acknowledgment
Authors: Oliver Robert M. , Hopkins David S. P.
Published: November 2008

Robert L. Armacost should be listed as one of the authors of our paper “An Equilibrium Flow Model of a University Campus,” Opns. Res. 20, 249–264 (1972).
Operations Research in Planning Political Campaign Strategies
Authors: Barkan Joel D. , Bruno James E.
Published: November 2008

Costs of running political campaigns have increased enormously over the last decade and methods have been sought to make campaigns, especially for national office, more efficient in their utilization of resources. This paper reports the results of applying operations-research techniques to the 1970 John V. Tunney Senatorial campaign. The principal task for the operations-research specialist was to develop a method to target precincts in the state for registration drives and for the get-out-the-vote effort in the campaign. In addition, “swing” precincts were identified for media and candidate attention.
Financing Mental-Health Services in the State of New York
Authors: Bodin Lawrence D. , Carroll T. Owen , Lee Allen , Stout Sally
Published: November 2008

Mental-health care is a major public-sector problem in the State of New York. We were asked by the Ways and Means Committee of the New York State Assembly to recommend a new fiscal structure with shared funding between the state and the counties to better achieve the objective of the state's mental-health-care program. We developed a simulation model for the problem and used it to design new funding plans; the results of our analysis have been written into legislation introduced into the New York State Assembly.
A Statistical Technique for the Control of Traffic Intensity in the Queuing Systems M/G/1 and GI/M/1
Authors: Bhat U. Narayan , Rao S. Subba
Published: November 2008

This paper presents a statistical technique for the control of the traffic intensity in single-server queuing systems with (i) Poisson arrivals and general service times and (ii) recurrent arrivals and exponential service times. The procedure is such that the system is readjusted only if the number of customers in the system either falls and stays beyond the upper control limit longer than a preassigned number of consecutive transitions or falls and stays below the lower control limit longer than a preassigned number of consecutive transitions. Methods are given to derive these two pairs of control limits using available transition probability tables, and tables of control limits have been provided for a selected number of parameter values in the queue with Poisson arrivals and general service times.