bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pricing Patterns of Cellular Phones and Phonecalls: A Segment-Level Analysis
Authors: Jain Dipak C. , Muller Eitan , Vilcassim Naufel J. 
Published: November 2008

One expectation of the U.S. Federal Communications Commission (FCC) in the early stages of the cellular communications industry was that the presence of two licensees in each market would ensure competition, and thereby result in declining prices over time for both cellular phones (handsets) and phonecalls. However, industry observers have noted recently that although the price of handsets has declined over time, the price of the phonecalls has not. We investigate this interesting pricing issue by modeling the market interaction between the providers of cellular services and also their interaction with customers using a game theoretic framework. A critical assumption in the development of our model is that there exist segments of customers with different valuations, usage levels, and price sensitivities for cellular service. Empirically, we provide support for the existence of two customer segments (viz., Business/Professional and Personal) from both secondary data on industry usage and revenue, and primary data collected from a conjoint analysis study of cellular service customers. From the latter source, we also establish that the Business/Professional customers are more sensitive to prices of phonecalls than the Personal segment. From our analytical model, we characterize the conditions under which penetration and skimming pricing strategies for the handsets are profit-maximizing from the sellers’ standpoint, and derive the corresponding price of phonecalls. One of our main analytical results is that a competitive structure can result in lower prices over time for the handset, but higher prices for the phonecalls, depending on production costs of the handset. We are thus able to provide a theoretical explanation for the observed price patterns for the handset and phonecalls.
Single-Stage Resource Allocation and Economic Lot Scheduling on Multiple, Nonidentical Production Lines
Authors: Bollapragada Ramesh , Rao Uday 
Published: November 2008

This paper focuses on simultaneous resource allocation, lot-sizing, and scheduling in a multimachine, deterministic ELSP environment. We consider the problem of apportioning item production to distinct manufacturing lines with different costs and capabilities (production rates). The objective is to minimize the long-run average production, setup, inventory, and shortage penalty costs (due to lost sales). Restricting attention to rotation schedules, we develop a concave minimization model of the problem, generate heuristic solutions and a lower bound on the cost of any feasible solution. Computational experiments indicate that our heuristic solution is within a few percent of the lower bound. We also investigate sensitivity of costs to model parameters, and illustrate how our model may be used to determine target values for equipment utilization.
A Branch-First, Cut-Second Approach for Locomotive Assignment
Authors: Ziarati Koorush , Soumis François , Desrosiers Jacques , Solomon Marius M. 
Published: November 2008

The problem of assigning locomotives to trains consists of selecting the types and number of engines that minimize the fixed and operational locomotive costs resulting from providing sufficient power to pull trains on fixed schedules. The force required to pull a train is often expressed in terms of horsepower and tonnage requirements rather than in terms of number of engines. This complicates the solution process of the integer programming formulation and usually creates a large integrality gap. Furthermore, the solution of the linearly relaxed problem is strongly fractional. To obtain integer solutions, we propose a novel branch-and-cut approach. The core of the method consists of branching decisions that define on one branch the projection of the problem on a low-dimensional subspace. There, the facets of the polyhedron describing a restricted constraint set can be easily derived. We call this approach branch-first, cut-second. We first derive facets when at most two types of engines are used. We then extend the branching rule to cases involving additional locomotive types. We have conducted computational experiments using actual data from the Canadian National railway company. Simulated test-problems involving two or more locomotive types were solved over 1-, 2-, and 3-day rolling horizons. The cuts were successful in reducing the average integrality gap by 52% for the two-type case and by 34% when more than 25 types were used. Furthermore, the branch-first, cut-second approach was instrumental in improving the best known solution for an almost 2,000-leg weekly problem involving 26 locomotive types. It reduced the number of locomotives by 11, or 1.1%, at an equivalent savings of $3,000,000 per unit. Additional tests on different weekly data produced almost identical results.
A Regional Production and Transportation Model
Authors: Berman Edward B. 
Published: November 2008

A linear programming model is set forth for maximizing a vector of final demand deliveries under both regional production constraints and transportation network constraints. The model is essentially designed to study short-run effects, and hence no provision is made for the expansion of either industrial or transportation capacities. Within available capacities, however, the location of production is chosen so as to maximize final demand deliveries. A rough dynamic version of the model is presented as well as an algorithm for reaching an approximation of the optimum solution.
Some Team Models of a Sales Organization
Authors: McGuire C. B. 
Published: November 2008

The models presented in this paper grew out of an attempt to apply the theory of teams of Marschak and Radner to the organization of the sales force in a typical wholesale bakery. As organizations go, the one we have chosen to analyze is an extremely simple one, even when—as is quite obviously not the case in what follows—it is viewed in its full complexity. At the risk of achieving results of quite limited general interest, a “simple,” easily quantified subject was deliberately chosen as the best place to begin to apply a theory that pretends to prescribe optimum decisions of a team in a precise way. We shall not here go much beyond a discussion of some mathematical models which deal only with the day-to-day problem a bakery sales force faces in attempting to “properly” supply its regular customers with a single product. Problems of advertising, of price policy, of product design, and of obtaining new customers are ignored. All the reader needs to know, to begin with, is that the sales force consists of truck-driver salesmen who daily visit each of their given customers (i.e. grocery stores) leaving, on consignment, an amount of bread to be decided by the salesman. At the end of the day the salesman returns to the plant and submits an order for the next day. For our purposes here the “organization” is characterized by the way in which these orders are jointly formed. In the last section, after the models have pin-pointed the organization problem, we shall return to a more detailed description of procedures found in practice.
A Model of Customer Behavior for the Task Manufacturing Corporation
Authors: Sprowls R. Clay , Asimow Morris 
Published: November 2008

The Task Manufacturing Corporation is a computer-simulated business firm. The objective is to simulate the operations of a real business firm on a greatly contracted time scale for use in education and research. The methodology is to build a business firm from detailed models of its subsystems. This paper discusses the model of one subsystem, the customer, who is viewed as a participant in an organization and whose behavior involves such participating notions as inducements, contributions, satisfactions, dissatisfactions and searches for alternative sources of supply.
Indices of the Hierarchical Structure of Industrial Organizations
Authors: Evan William M. 
Published: November 2008

A postulate common to both the structural-functional theory of social stratification and to organization theory is that hierarchical organization is functionally necessary. An alternative formulation of this postulate—which is probably more heuristic—is that different degrees of hierarchical organization have different consequences for total and partial social systems. The present inquiry into the problem of measuring organizational hierarchy begins with the selection of three central dimensions of organization: the hierarchy of skills, the hierarchy of rewards, and the hierarchy of authority. For each dimension an attempt is then made to develop and codify one or more indicators. The question of the empirical application of the indicators of the hierarchical dimensions in turn leads to a consideration of the problems of index construction, analysis of change over time, analysis of causes and consequences of variation in degree of organizational hierarchy, and of comparative research, whether cross-national, cross-organizational, or experimental in character.
The Effect of Promotional Effort on Sales
Authors: Magee John F. 
Published: November 2008

The management of an industrial enterprise is constantly faced with the problem of deciding how much advertising, selling, or promotional effort is economically justified. A reasonable response to this question implies at least an intuitive knowledge of the relation between sales volume and promotional effort. This paper presents a case study of the development of such a relationship. 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—Report on the First Summer Program on Operations Research at the Massachusetts Institute of Technology, June 16–July 2, 1953
Authors: Morse Philip M. 
Published: November 2008

This 15-day special course in operations research, for persons from industry, government, and the military services, was planned and supervised by the Institute Committee on Operations Research: Prof. Philip M. Morse, Department of Physics, Chairman; Prof. G. P. Wadsworth, Department of Mathematics; Prof. N. C. Dahl, Department of Mechanical Engineering; Prof. M. J. Gordon, School of Industrial Management; Prof. W. K. Linvill, Department of Electrical Engineering; Prof. H. M. Paynter, Department of Civil Engineering; and Mr. A. N. Watson, Research Associate, School of Industrial Management. 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 Media Planning Calculus
Authors: Little John D. C. , Lodish Leonard M. 
Published: November 2008

A convenient on-line computer system selects and schedules advertising media. The system consists of a market-response model, a heuristic search routine, and a conversational input-output program. The user supplies a list of media options, a budget, and various objective and subjective data about the media options and the desired audience. The system selects a set of options and schedules them over time, seeking to maximize total market response. The model of market response works as follows: The population is divided into market segments. People in each segment are characterized by their sales potential and media habits. Ads placed in the media options lead people to be exposed to the advertising. The pattern of exposures in each market segment is determined by media coverage and duplication data. People tend to forget exposures and so the retained exposure level decays in the absence of new advertising. The response of an individual, in terms of the fraction of sales potential realized by the advertiser, increases with exposure level but with diminishing returns. Total market response is a sum over people, market segments, and time periods. The calculation of response is based on analytic formulas that are computationally very efficient. A maximum-seeking, heuristic calculation starts with any schedule, adds options with a high increment of response per dollar and deletes options with a low increment per dollar until no more improvement can be found for the given budget. An on-line system, called mediac, permits the use of model and heuristic at a remote console of a time-shared computer. Communication with the computer is conversational and largely self-explanatory. The system is operational. Computing costs have been a fraction of a per cent of the cost of the media scheduled. Improvements over previous schedules, as calculated by the model from the user's input data, have run from 5 per cent to over 20 per cent.
The Problem of Testing for the Fraction of Defectives
Authors: Breakwell J. V. 
Published: November 2008

A balance is sought between (1) the cost of testing for reliability and (2) the risks, because of limiting the testing, of either accepting an insufficiently reliable product or rejecting a sufficiently reliable one. The latter risk is generally less serious than the former. With a suitably defined pay-off function, “optimum” parameters are obtained both for a fixed-size test and a sequential test of the type introduced by Wald. The mathematical treatment is valid except for very high reliabilities. Modifications are discussed for (i) an optimum sequential test when the pay-off function includes some uncertainty as to what is meant by sufficiently reliable, and (ii) an optimum sequential test between two rival products. Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Threats to the Growth of Operations Research in Business and Industry
Authors: Rinehart Robert F. 
Published: November 2008

It is customary at annual meetings of professional societies such as ours, for the president to devote much or all of his retiring address to the many accomplishments and advances of the organization during the preceding year or years. In the case of ORSA we call point with some pride to our 40 per cent increase in membership, to the increased health and size of our Journal and to other signs of healthy growth. Our optimism regarding past achievements should not be permitted to obscure, however, those dangers or threats to our continued development which may loom in the future. I propose, therefore, to be the devil's advocate and to depart from precedent by playing the part of a viewing-with-alarm prognosticator rather than that of a pointing-with-pride historian. Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Mathematical Foundations and Computational Methods for a Digital Logic Machine
Authors: Ledley Robert S. 
Published: November 2008

The manipulations of the propositional calculus (and the analogous Boolean algebra) have recently become of fundamental importance in fields other than set theoretical proofs of pure mathematics. For example, in the analysis and evaluation of intelligence and military reports, preparation and analysis of tactical methods and principles, complex logical nonnumerical problems often arise more frequently than do problems of a numerical nature. Consequently there is the need for a systematic method of analyzing and solving propositional functions and equations. The purpose of this paper is to present the systematic rules of an “arithmetic” for handling propositional functions and equations, formulated in a manner amenable to easy computation and mechanization. Among the important results given are: (a) a simple method of expressing a propositional calculus in terms of the shortest digitalized words possible, (b) a systematic method for generating the simplest and absolute simplest forms for Boolean functions, (c) a method for systematically generating all true and false implications of given propositions, (d) a method for systematically generating all possible changes of variables (i.e., substitution of new variables) that can be made on a propositional calculus while preserving the logical meaning, and (e) the systematic generation of all solutions to any number of simultaneous propositional equations in any number of unknowns. The solution of this latter problem implies the ability to perform manipulations with propositional variables in a manner analogous to manipulations of ordinary algebraic equations. A number of illustrative applications to military situations are given, including an analysis of certain propositions and conclusions of Clausewitz. Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
Information Theory and Man-Machine Systems
Authors: Krulee Gilbert K. 
Published: November 2008

Information theory has been used recently as the basis for some experimental studies of the abilities of humans as processors of information. One possible approach to the analysis of man-machine systems is to consider the implications of such experimental knowledge for the design of man-machine systems. The functions performed by human operators in these systems are primarily those of control of the energy resources of the system. Control functions involve, by their very nature, the availability of relevant information and the opportunity to transmit control decisions reached on the basis of this information. It is important not only that enough information be available to an operator in order to carry out his control responsibilities, but also that these tasks be not complicated unnecessarily by the provision of too much or irrelevant information. Moreover, in applying an informational analysis to control tasks, it is essential that consideration be given as to what sorts of categories are perceptually possible for operators since any analysis which does not take into account certain perceptual limitations of humans is likely to be invalid. Following this point of view it is suggested that intelligent design of man-machine systems involves compatibility between the control requirements of a system and the capabilities of the men in the system. Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
On the Optimal Operating Policy for the Machine Repair Problem When Failure and Repair Times Have Erlang Distribution
Authors: Coleman Goheen Lola 
Published: November 2008

In the machine repair problem we are given m + n identical machines, m operating and n spares. All machines are independent of one another. When an operating machine fails, it is immediately sent to one of K repair facilities and immediately replaced by a spare machine, if one is available. Repair facility i has sj independent and identical repairmen, 1 ≦ i ≦ k. Repairmen work on machines on a one-to-one basis. The cost of repairing a failed machine is a constant depending upon the facility performing the repair. Moreover, if the number of operating machines falls below m, a penalty is accrued at a rate depending on the shortage. This paper treats the following decision problem: to assign (at the time of each failure) the failed machine to a repair facility so as to minimize the long-run average cost when K ≧ 2 and failure and repair times have Erlang distribution. We show that determining a stationary policy to minimize long-run average cost and long-run average expected cost is equivalent to solving a certain nonlinear program. The nonlinear program has a simple structure and an optimal solution.
The Influence of Vehicular Speed and Spacing on Tunnel Capacity
Authors: Olcott Edward S. 
Published: November 2008

In the flow of traffic through vehicular tunnels, it is shown that an approximate linear relationship between speed and density of traffic exists, whereby, as the average speeds of vehicles increase, the density of the traffic stream decreases. The relationship is used to establish a series of theoretical equations that, in turn, permit the determination of optimum conditions of speed and spacing required to produce maximum volumes under given conditions of traffic composition. The significance of uniform speeds and spacings in moving large volumes of traffic, which is disclosed in this study, has been clearly recognized in practice. In the Lincoln Tunnel in New York City, the Port Authority has established minimum speed limits, banned slow under-powered trucks from the tunnel, and erected a number of signs to influence motorists to maintain a specified distance behind preceding vehicles. All of these traffic control devices are directed toward an optimizing of vehicular speeds and spacings, and have resulted in significant increases in maximum hourly traffic volumes accommodated by the tunnel. 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—Further Remarks on the Direct Use of Extremal Principles in Solving Certain Optimizing Problems Involving Inequalities
Authors: Klein B. 
Published: November 2008

In reply to a recent commentary on the paper, “Direct Use of Extremal Principles in Solving Certain Optimizing Problems Involving Inequalities,” which appeared in the May, 1955 issue of this Journal (p. 168), the author wishes to make some remarks. Operations Research, ISSN 0030-364X, was published as Journal of the Operations Research Society of America from 1952 to 1955 under ISSN 0096-3984.
On the Objective Function Behavior in (s, S) Inventory Models
Authors: Sahin Izzet 
Published: November 2008

The most common measure of effectiveness used in determining the optimal (s, S) inventory policies is the total cost function per unit time, E(s, Δ), Δ = S − s. In stationary analysis, this function is constructed through the limiting distribution of on-hand inventory, and it involves some renewal-theoretic elements. For Δ ≥ 0 given, E(s, Δ) turns out to be convex in s, so that the corresponding optimal reorder point, s1(Δ), can be characterized easily. However, E(s1(Δ), Δ) is not in general unimodal on Δ ≥ 0. This requires the use of complicated search routines in computations, as there is no guarantee that a local minimum is global. Both for periodic and continuous review systems with constant lead times, full backlogging and linear holding and shortage costs, we prove in this paper that E′(s1(Δ), Δ) = 0, Δ ≥ 0, is both necessary and sufficient for a global minimum (E(s1(Δ), Δ) is pseudoconvex on Δ ≥ 0) if the underlying renewal function is concave. The optimal stationary policy can then be computed efficiently by a one-dimensional search routine. The renewal function in question is that of the renewal process of periodic demands in the periodic review model and of demand .sizes in the continuous review model.
The Optimality of Unbalancing Both Workloads and Machine Group Sizes in Closed Queueing Networks of Multiserver Queues
Authors: Stecke Kathryn E. , Solberg James J. 
Published: November 2008

Using a closed queueing network model, we explore the consequences of varying workloads among multiserver queues that may be of unequal size. In addition, we solve the problem of assigning servers of similar types to the queues in the network to maximize expected throughput. We show that (1) unbalanced configurations of assigned servers are superior to balanced ones, and (2) unbalanced workloads are better than balanced ones. We find that there can be significant differences in system throughput from balanced versus unbalanced configurations/workloads. Finally, we discuss applications to planning problems of flexible manufacturing systems.