bluuebunny/crossref_metadata_2025 huggingface dataset:
The single server queue in discrete time‐numerical analysis I
Authors: Neuts Marcel F.
Published: May 2007

This is the first of a sequence of papers dealing with the computational aspects of the transient behavior of queues in discrete time

It is shown that for a substantial class of queues of practical interest, a wealth of numerical information may be obtained by relatively unsophisticated methods

This approach should prove useful in the analysis of unstable queues which operate over a limited time interval, but is by no means limited to such queues

Mathematically the service unit is modeled in terms of a multivariate Markov chain, whose particular structure is used in iterative computation. Many important queue features may then be derived from the n‐step transition probabilities of this chain.
Hyperbolic integer programming
Authors: Grunspan M. , Thomas M. E.
Published: May 2007

The hyperbolic integer program is treated as a special case of a hyperbolic program with a finite number of feasible points. The continuous hyperbolic program also belongs to this class since its solution can be obtained by considering only the extreme points of the feasible set. A general algorithm for solving the hyperbolic integer program which reduces to solving a sequence of linear integer problems is proposed. When the integer restriction is removed, this algorithm is similar to the Isbell‐Marlow procedure. The geometrical aspects of the hyperbolic problem are also discussed and several cutting plane algorithms are given.
Convergence of the bounded fixed charge programming problem
Authors: Tiplitz Charles I.
Published: May 2007

Calculating the solution for a mixed integer linear programming problem has been problematic for any sizable dimension because of the time required. Accordingly, an improved method for the fixed charge problem is presented here. The method is a modification of a bounding technique first suggested by Balinski, and it exploits fully the ratio of costio‐use, first described by Cooper and Drebes. It exploits those local properties which have global application so that enumeration is confined to those relatively few combinations which cannot be evaluated otherwise.
An empirical bayes estimator for the scale parameter of the two‐parameter weibull distribution
Authors: Bennett G. Kemble , Martz H. F.
Published: May 2007

An empirical Bayes estimator is given for the scale parameter in the two‐parameter Weibull distribution. The scale parameter is assumed to vary randomly throughout a sequence of experiments according to a common, but unknown, prior distribution. The shape parameter is assumed to be known, however, it may be different in each experiment. The estimator is obtained by means of a continuous approximation to the unknown prior density function. Results from Monte Carlo simulation are reported which show that the estimator has smaller mean‐squared errors than the usual maximum‐likelihood estimator.
Optimal allocation of unreliable components for maximizing expected profit over time
Authors: Henin Claude G.
Published: May 2007

In the present paper, we solve the following problem: Determine the optimum redundancy level to maximize the expected profit of a system bringing constant returns over a time period T; i. e., maximize the expression \documentclass{article}\pagestyle{empty}\begin{document}$ P\int_0^T {Rdt - C} $\end{document}, where P is the return of the system per unit of time, R the reliability of this system, C its cost, and T the period for which the system is supposed to work

We present theoretical results so as to permit the application of a branch and bound algorithm to solve the problem. We also define the notion of consistency, thereby determining the distinction of two cases and the simplification of the algorithm for one of them.
Using decomposition in integer programming
Authors: Schrage Linus
Published: May 2007

When implicit enumeration algorithms are used for solving integer programs, a form of primal decomposition can be used to reduce the number of solutions which must be implicitly examined. If the problem has the proper structure, then under the proper decomposition a different enumeration tree can be defined for which the number of solutions which must be implicitly examined increases with a power of the number of variables rather then exponentially. The proper structure for this kind of decomposition is that the southwest and northeast corners of the constraint matrix be zero or equivalently that the matrix be decomposable except for linking columns. Many real traveling salesmen, plant location, production scheduling, and covering problems have this structure.
Numerical treatment of a class of semi‐infinite programming problems
Authors: Gustafson S. Å. , Kortanek K. O.
Published: May 2007

Many optimization problems occur in both theory and practice when one has to optimize an objective function while an infinite number of constraints must be satisfied. The aim of this paper in to describe methods of handling such problems numerically in an effective manner. We also indicate a number of applications.
Optimal design of a multi‐item, multi‐location, multi‐repair type repair and supply system
Authors: Porteus Evan L. , Lansdowne Zachary F.
Published: May 2007

The design of a system with many locations, each with many items which may fail while in use, is considered. When items fail, they require repair; the particular type of repair being governed by a probability distribution. As repairs may be lengthy, spares are kept on hand to replace failed items. System ineffectiveness is measured by expected weighted shortages over all items and locations, in steady state. This can be reduced by either having more spares or shorter expected repair times. Design consists of a provisioning of the number of spares for each item, by location; and specifying the expected repair times for each type of repair, by item and location. The optimal design minimizes expected shortages within a budget constraint, which covers both (i) procurement of spares and (ii) procurement of equipment and manning levels for the repair facilities. All costs are assumed to be separable so that a Lagrangian approach is fruitful, yielding an implementable algorithm with outputs useful for sensitivity analysis. A numerical example is presented.
Finding equivalent transportation formulations for constrained transportation problems
Authors: Glover F. , Klingman Darwin , Ross G. Terry
Published: May 2007

This paper describes a procedure for determining if constrained transportation problems (i.e., transportation problems with additional linear constraints) can be transformed into equivalent pure transportation problems by a linear transformation involving the node constraints and the extra constraints. Our results extend procedures for problems in which the extra constraints consist of bounding certain partial sums of variables.
Computerized scheduling of seagoing tankers
Authors: McKay M. D. , Hartley H. O.
Published: May 2007

Computerized Scheduling of Seagoing Tankers The tanker scheduling problem considered in this paper is that of the Defense Fuel Supply Center (DFSC) and the Military Sealift Command (MSC) in the worldwide distribution of bulk petroleum products. Routes and cargoes which meet delivery schedule dates for a multiplicity of product requirements at minimum cost are to be determined for a fleet of tankers. A general mathematical programming model is presented, and then a mixed integer model is developed which attempts to reflect the true scheduling task of DFSC and MSC as closely as possible. The problem is kept to within a workable size by the systematic construction of a set of tanker routes which does not contain many possible routes that can be judged unacceptable from practical considerations alone.
On nash subsets of bimatrix games
Authors: Millham C. B.
Published: May 2007

This work considers a class of bimatrix games to which some well‐known structure theorems of 0‐sum matrix games can be made to generalize. It is additionally shown how to construct such games and how to generate the equilibrium points defining a given game as a member of that class.
On the evaluation of investment proposals having multiple attributes
Authors: Trippi Robert R.
Published: May 2007

A framework is developed for analyzing the likelihood of acceptance of an investment project proposal when objectives are uncertain. The foundation is a utility model of top management's choice process, modified if need be through a Bayesian approach which takes into account any apparent inconsistency in the history of past proposal acceptances and rejections.
Structural models of award fee contracts
Authors: Marshall Clifford W.
Published: May 2007

This paper describes the construction of a mathematical model structure in a particular area of management. In addition it is intended as an illustration of how appropriate levels of mathematics can be utilized in management research when original formulations lack sufficient precision for conducting quantitative analyses. The specific area studied deals with the formulation and analysis of contract types. In particular the award fee type contract is treated. At present mathematical structure models for other contract types have received considerable attention, but award fee types have not been structured in mathematical terms. The paper provides a discussion of model formulation for award fee contracts, develops a detailed example of such a structure, and illustrates that model by numerical examples indicating the application of such models to the formulation and analysis of award fee contracts.
Managerial inventory formulations with stockout objectives and fiscal constraints
Authors: Schroeder Roger C.
Published: May 2007

Most inventory formulations seek to minimize the sum of ordering costs, holding costs, and stockout costs: however, management often directs inventory policy by specifying a maximum investment level and/or a purchasing budget constraint. Within these limitations, they expect lower level managers to optimize some level of customer satisfaction, such as minimum stockouts or minimum shortages. The author has developed several cases of these “managerial” inventory formulations and has presented some computational results.
Simultaneous equation production functions (cobb‐douglas type) for decisions pertaining to sea‐based tactical air resources
Authors: Lewis Chantee
Published: May 2007

This paper proposes the use of a set of simultaneous, modified Cobb‐Douglas production functions to determine the “best” mix of aircraft inputs (men, spare parts, support equipment, etc.) to achieve certain levels of output. The simultaneous equations are “solved” by the use of proxy values in an iterative search process. Tests of this production function model indicate that real world data fits quite well (R2 ranges from 0.884 to 0.951) and the residuals do not appear to have any significant bias.

The aircraft production functions for several types of aircraft (F‐4, A‐7, A‐6, A‐4) have been maximized for a fixed budget and specific constraints. A potential increase in output of up to 10 percent appears possible. In general the marginal value of spare parts surpasses the other inputs.
A two product dynamic economic lot size production model with either‐or production constraints
Authors: Crabill Thomas B. , Jaquette David L.
Published: May 2007

This paper considers the production of two products with known demands over a finite set of periods. The production and inventory carrying costs for each product are assumed to be concave. We seek the minimum cost production schedule meeting all demands, without backlogging, assuming that at most one of the two products can be produced in any period. The optimization problem is first stated as a nonlinear programming problem, which allows the proof of a result permitting the search for the optimal policy to be restricted to those which produce a product only when its inventory level is zero. A dynamic programming formulation is given and the model is then formulated as a shortest route problem in a specially constructed network.
On maximum internally stable sets of a graph
Authors: Nieminen U. J.
Published: May 2007

The paper makes some remarks on the paper of Hakimi and Frank and shows a simplified way of applying the concept of alternating forest. An algorithm for finding a maximum internally stable set of an undirected graph is constructed and some examples are given.
Efficient computational devices for the capacitated transportation problem
Authors: Langley Robert W. , Kennington Jeff , Shetty C. M.
Published: May 2007

This paper presents the details for applying and specializing the work of Ellis Johnson [10] and [11] to develop a primal code for the well‐known capacitated transportation problem. The code was developed directly from the work of Johnson, but is similar to codes developed by Glover, Karney, Klingman, and Napier [6] and Srinivasan and Thompson [14]. The emphasis in the presentation is the use of the graphical representation of the basis to carry out the revised simplex operations. This is a means of exploiting the special structure and sparseness of the constraint matrix to minimize computational effort and storage requirements. We also present the results of solving several large problems with the code developed.
Optimization of strategic defenses to provide specified post‐attack production capacities
Authors: Bracken Jerome , McGill James T.
Published: May 2007

This paper presents a model for choosing a minimum‐cost mix of strategic defenses to assure that specified production capacities for several economic sectors survive after a nuclear attack. The defender selects a mix of strategic defenses for each of several geographic regions. The attacker chooses an allocation of attacking weapons to geographic regions, within specified weapon inventories. The attack is optimized against any economic sector. This formulation allows the defense planner the capability to assess the results of the optimal defense structure for a “worst case” attack. The model is a mathematical program with nonlinear programming problems in the constraints; an example of its application is given and is solved using recently developed optimization techniques.
Properties of an approximate hazard transform
Authors: Esary J. D. , Hayne W. J.
Published: May 2007

The calculation of the exact reliability of complex systems is a difficult and tedious task. Consequently simple approximating techniques have great practical value.

The hazard transform of a system is an invertible transformation of its reliability function which is convenient and useful in both applied and theoretical reliability work. A simple calculus for finding an approximate hazard transform for systems formed by series and parallel combinations of components is extended so that it can be used for any coherent system. The extended calculus is shown to lead to conservative approximations.

A first order version of the extended calculus is also discussed. This method of approximation is even more simple to use, but is not always conservative. Examples of its application indicate that it is capable of giving quite accurate results.
Optimal schedules for special structure flowshops
Authors: Gupta Jatinder N. D.
Published: May 2007

This paper considers the problem of scheduling a given number of jobs on a specified number of machines in a flowshop where the objective function is to minimize the total throughput time in which all jobs complete processing on all machines. Based on the combinatorial analysis of the problem, several simple algorithms are developed for solving special structure flowshop scheduling problems where the process times are not completely random, but bear a well‐defined relationship to one another. The proposed algorithms are both simple and computationally efficient and can optimally solve large‐sized problems even with manual computational devices.
An operator theory of parametric programming for the generalized transportation problem‐III‐weight operators
Authors: Balachandran V. , Thompson G. L.
Published: May 2007

This paper investigates the effect on the optimum solution of a capacitated generalized transportation problem when any coefficient of any row constraint is continuously varied as a linear function of a single parameter. The entire analysis is divided into three parts. Results are derived relative to the cases when the coefficient under consideration is associated, to a cell where the optimal solution in that cell attains its lower bound or its upper bound. The discussion relative to the case when the coefficient under consideration is associated to a cell in the optimal basis is given in two parts. The first part deals with the primal changes of the optimal solution while the second part is concerned with the dual changes. It is shown that the optimal cost varies in a nonlinear fashion when the coefficient changes linearly in certain cases. The discussion in this paper is limited to basis‐preserving operators for which the changes in the data are such that the optimum bases are preserved. Relevant algorithms and illustrations are provided throughout the paper.
A computation procedure for the exact solution of location‐allocation problems with rectangular distances
Authors: Love Robert F. , Morris James G.
Published: May 2007

A method is presented to locate and allocate p new facilities in relation to n existing facilities. Each of the n existing facilities has a requirement flow which must be supplied by the new facilities. Rectangular distances are assumed to exist between all facilities. The algorithm proceeds in two stages. In the first stage a set of all possible optimal new facility locations is determined by a set reduction algorithm. The resultant problem is shown to be equivalent to finding the p‐median of a weighted connected graph. In the second stage the optimal locations and allocations are obtained by using a technique for solving the p‐median problem.
Approximations for the consolidation of multiechelon repair facilities
Authors: Morey Richard C.
Published: May 2007

This paper develops and illustrates an approximate approach for analytically assessing the impacts on both costs and service of consolidation of repair facilities. The repair facilities are two echelon generalizations of the classical repairmen problem in which two types of failures, say major and minor, can occur, each type requiring repair at a different echelon: The questions addressed are the reductions possible in spares, repairmen, and service rates due to the consolidated system's increased efficiency, as well as the physical separation between the users and the consolidated repair facility that is economical. The method of analysis is based upon asymptotic approximations developed for the repairmen problem, valid when the number of operational equipments is large (greater than 50); it is helpful since it provides a tractable means for predicting the steady‐state performance of the decentralized and consolidated installations as a function of the many parameters involved without having to resort to an exhaustive computation of all the exact steady‐state probabilities.
Bayesian estimation: A sensitivity analysis
Authors: Canavos George C.
Published: May 2007

The robustness of the assigned prior distribution in a Bayesian estimation problem is examined. A Bayesian analysis for a stochastic intensity parameter of a Poisson distribution is summarized in which the natural conjugate is assigned as the prior distribution of the random parameter. The sensitivity analysis is carried out by assuming the existence of a true prior which is different in form from that of the assigned prior distribution. By using mean‐squared error as a measure of performance, the ensuing Bayes decision function is compared to the corresponding minimum variance unbiased estimator. Results indicate that the Bayes estimator is largely robust to deviations from the assigned prior and remains squared‐error superior to the MVU type within a broad region.
Control charts for exponentially distributed product life
Authors: Yegulalp Tuncel M.
Published: May 2007

This paper introduces a special control chart procedure for exponentially distributed product life. Statistical control of product life in manufacturing requires continuing life tests of manufactured product so as to detect changes in product life and take appropriate corrective action. These life testing experiments may become exceedingly time consuming and thus can be both impractical because of serious time delays in implementing corrective action on the process when indicated, and quite uneconomical.

It is desirable to inquire into the character of life testing by means of a control chart procedure based on the real time to first failure within given samples. Measuring the real minimum life provides a considerable reduction in duration of the testing procedure and in the number of specimens destroyed, yielding a considerable economy over the Shewhart's X control chart.
Approximate probability distributions for the extreme spread
Authors: Taylor Malcolm S. , Grubbs Frank E.
Published: May 2007

The extreme spread, or greatest distance between all pairs of impact points on a target, is often used as a rapid measure of dispersion or precision of shot groups on a target. It is therefore desirable to know its statistical properties. Since the exact theoretical distribution has not yet been worked out, this paper examines the accuracy of several approximations which are checked against large sample monte carlo values. We find in particular that for the sample sizes considered the extreme spread can be approximated well by a Chi variate.
Optimal inventory policy when stockouts alter demand
Authors: Caine G. J. , Plaut R. H.
Published: May 2007

An inventory model in which future demand is affected by stockouts has been considered recently by B. L. Schwartz. Some generalizations of Schwartz's model are presented in this paper and properties of the optimal policies are determined. In the case of deterministic demand, a set‐up cost is included and a mixture of backlogged and nonbacklogged orders is allowed during stockout. It is proved that the optimal policy entails either no stockout or continual stockout, depending on the values of three parameters. For stochastic demand, the effect of stockouts on demand density is postulated, the resulting optimal inventory policy is discussed, and an example involving an exponential density function is then analyzed in detail.
Scheduling to minimize the weighted sum of completion times with secondary criteria
Authors: Burns Richard N.
Published: May 2007

A result of Smith previously published in this journal [3], on the use of secondary criteria in scheduling problems, is shown to be incorrect and a counter example is presented.

Heck and Roberts [2] suggested that their paper would be extended in the same way Smith's algorithm was. A new algorithm is given that converges to a local optimum for both problems.
Redundant spares allocation to reduce reliability costs
Authors: Shaw Leonard , Sinkar Sharad G.
Published: May 2007

The problem considered here is the optimal selection of the inventory of spares for a system built from two kinds of modules, the larger of which can be connected so it performs the role of the smaller one. The optimal inventory is the least costly one which achieves a specified probability that the spares will not be exhausted over the design lifetime. For some costs and failure rates it is most economical to use the larger module for both roles, due to the resulting increase in flexibility in the deployment of a single type of spare module.

Both analytical and simulation methods have been used to study this problem.
An asymptotically optimal inspection policy
Authors: Anbar Dan
Published: May 2007

An inspection model in life testing situations is discussed. The system under study is assumed to consist on n independent components all of which fail independently in an exponential fashion. Failures can be discovered only through inspection. The experimenter is assumed to lack the knowledge of the parameter of the exponential distribution. A stochastic sequential inspection policy is suggested which uses the data collected through experimentation to estimate the unknown parameter. It is shown that this policy is asymptotically optimal. Some numerical demonstrations are included.
Improved convergence rate results for a class of exponential penalty functions
Authors: Murphy Frederic H.
Published: May 2007

An improved theoretical rate of convergence is shown for a member of the class of exponential penalty function algorithms. We show that the algorithm has a superlinear convergence rate.
A dynamic nonlinear constrained optimal replacement model
Authors: Kalman Peter J. , Wickström Bengt‐Arne
Published: May 2007

A stochastically constrained optimal replacement model for capital equipment is constructed. Each piece of capital equipment, or machine, is characterized by its age and “utility” or “readiness” class. The readiness of a machine at any age is a stochastic function of its initial utility class and its age.

The total discounted replacement cost of several replacement streams, each commencing with an initial machine, is minimized with respect to the replacement age and initial utility class of each machine, subject to a readiness constraint stating the lower bound on the expected number of machines in each utility class at any time. A general solution procedure is outlined and a specific case is solved in detail.
A two‐echelon inventory model with purchases, dispositions, shipments, returns and transshipments
Authors: Hoadley Bruce , Heyman Daniel P.
Published: May 2007

This paper presents a one‐period two‐echelon inventory model with one warehouse in the first echelon and n warehouses in the second echelon. At the beginning of the period the stock levels at all facilities are adjusted by purchasing or disposing of items at the first echelon, returning or shipping items between the echelons and transshipping items within the second echelon. During the period, demands (which may be negative) are placed on all warehouses in the second echelon and an attempt is made to satisfy shortages either by an expedited shipment from the first echelon to the second echelon or an expedited transshipment within the second echelon. The decision problem is to choose an initial stock level at the first echelon (by a purchase or a disposition) and an initial allocation so as to minimize the initial stock movement costs during the period plus inventory carrying costs and system shortage costs at the end of the period.

It is shown that the objective function takes on one of four forms, depending on the relative magnitudes of the various shipping costs. All four forms of the objective function are derived and proven to be convex.

Several applications of this general model are considered. We also consider multi‐period extensions of the general model and an important special case is solved explicitly.
Convex and polaroid extensions
Authors: Burdet Claude‐Alain
Published: May 2007

In an effort towards a comprehensive and unified theory, this note presents some new results in the area of non‐convex programming within the framework of convex (sets and function) analysis.

The entire study is primarily devoted to the development of useful tools for extreme point programs (such as concave or integer programs).
Cyclical job sequencing on multiple sets of identical machines
Authors: Stern Helman I. , Rodriguez Edgardo P. , Utter Merlin L.
Published: May 2007

The problem posed in this paper is to sequence or route n jobs, each originating at a particular location or machine, undergoing r−1 operations or repairs, and terminating at the location or machine from which it originated. The problem is formulated as a 0‐1 integer program, with block diagonal structure, comprised of r assignment subproblems; and a joint set of constraints to insure cyclical squences. To obtain integer results the solutions to each subproblem are ranked as required and combinations thereof are implicitly enumerated. The procedure may be terminated at any step to obtain an approximate solution. Some limited computational results are presented.
A note on a confidence interval for an interclass mean
Authors: Jayachandran T.
Published: May 2007

An exact confidence interval for an interclass mean, that is, the mean of a composite sample made up several subsamples of unequal sizes ni, is presented.
A priori error bounds for procurement commodity aggregation in logistics planning models
Authors: Geoffrion A. M.
Published: May 2007

A complete logistical planning model of a firm or public system should include activities having to do with the procurement of supplies. Not infrequently, however, procurement aspects are difficult to model because of their relatively complex and evanescent nature. This raises the issue of how to build an overall logistics model in spite of such difficulties. This paper offers some suggestions toward this end which enable the procurement side of a model to be simplified via commodity aggregation in a “controlled” way, that is, in such a manner that the modeler can know and control in advance of solving his model how much loss of accuracy will be incurred for the solutions to the (aggregated) overall model.
A node covering algorithm
Authors: Balas Egon , Samuelsson Haakon
Published: May 2007

This paper describes a node covering algorithm, i.e., a procedure for finding a smallest set of nodes covering all edges of an arbitrary graph. The algorithm is based on the concept of a dual node‐clique set, which allows us to identify partial covers associated with integer dual feasible solutions to the linear programming equivalent of the node covering problem. An initial partial cover with the above property is first found by a labeling procedure. Another labeling procedure then successively modifies the dual node‐clique set, so that more and more edges are covered, i.e., the (primal) infeasibility of the solution is gradually reduced, while integrality and dual feasibility are preserved. When this cannot be continued, the problem is partitioned and the procedure applied to the resulting subproblems. While the steps of the algorithm correspond to sequences of dual simplex pivots, these are carried out implicitly, by labeling. The procedure is illustrated by examples, and some early computational experience is reported. We conclude with a discussion of potential improvements and extensions.
Two‐characteristic markov‐type manpower flow models
Authors: Hayne W. J. , Marshall K. T.
Published: May 2007

A two‐dimensional state space Markov Model of a Manpower System with special structure is analyzed. Examples are given from the military services. The probabilistic properties are discussed in detail with emphasis on computation. The basic equations of manpower stocks and flows are analyzed.
Estimation of ordered parameters from k stochastically increasing distributions
Authors: Chen Hubert J.
Published: May 2007

There are given k (⩾ 2) univariate cumulative distribution functions (c.d.f.'s) G(x; θi) indexed by a real‐valued parameter θi, i=1,…, k. Assume that G(x; θi) is stochastically increasing in θi. In this paper interval estimation on the ith smallest of the θ's and related topics are studied. Applications are considered for location parameter, normal variance, binomial parameter, and Poisson parameter.
Force‐annihilation conditions for variable‐coefficient lanchester‐type equations of modern warfare
Authors: Taylor James G. , Comstock Craig
Published: May 2007

This paper develops a mathematical theory for predicting force annihilation from initial conditions without explicitly computing force‐level trajectories for deterministic Lanchester‐type “square‐law” áttrition equations for combat between two homogeneous forces with temporal variations in fire effectivenesses (as expressed by the Lanchester attrition‐rate coefficients). It introduces a canonical auxiliary parity‐condition problem for the determination of a single parity‐condition parameter (“the enemy force equivalent of a friendly force of unit strength”) and new exponential‐like general Lanchester functions. Prediction of force annihilation within a fixed finite time would involve the use of tabulations of the quotient of two Lanchester functions. These force‐annihilation results provide further information on the mathematical properties of hyperbolic‐like general Lanchester functions: in particular, the parity‐condition parameter is related to the range of the quotient of two such hyperbolic‐like general Lanchester functions. Different parity‐condition parameter results and different new exponential‐like general Lanchester functions arise from different mathematical forms for the attrition‐rate coefficients. This theory is applied to general power attrition‐rate coefficients: exact force‐annihilation results are obtained when the so‐called offset parameter is equal to zero; while upper and lower bounds for the parity‐condition parameter are obtained when the offset parameter is positive.
A note on distribution‐free tolerance limits
Authors: Govindarajulu Z.
Published: May 2007

This note presents methods for solving for any one of the four parameters (such as sample size) involved in the construction of distribution‐free tolerance limits in terms of the other three. These solutions are based on a normal approximation to the incomplete beta function. Numerical examples indicate that the approximations are very reasonable. Also considered are tolerance limits with a specified precision.
A parallel sequencing algorithm for minimizing total cost
Authors: Rajaraman M. K.
Published: May 2007

The problem of sequencing jobs on parallel processors when jobs have different available times, due dates, penalty costs and waiting costs is considered. The processors are identical and are available when the earliest job becomes available and continuously thereafter. There is a processor cost during the period when the processor is available for processing jobs. The proposed algorithm finds the sequence (or sequences) with minimum total cost (sum of waiting, penalty and processor costs.). A proof of the algorithm and numerical results are given.
Adaptive forecasting of the size of a work force subject to random withdrawals
Authors: Zacks S. , Haber S. E.
Published: May 2007

Adaptive forecasting procedures are developed for predicting the size of a work force which is subject to random withdrawals. The procedures are illustrated using Marine Corps data in which four stages of service for incoming cohorts are distinguished. Using these data, three forecasting procedures—conditional maximum likelihood estimation of prediction intervals; tolerance intervals; and Bayes prediction intervals—are compared.
A note on values and multilinear extensions
Authors: Roth Alvin E.
Published: May 2007

An axiomatic formulation is given of a class of values for cooperative games. This class includes the Shapley value and the Banzhaf index, and is related to the multilinear extension of a game.
Explicit steady state solutions for a particular M(x)/M/1 queueing system
Authors: Jensen George L. , Paulson Albert S. , Sullo Pasquale
Published: May 2007

An explicit steady state solution is determined for the distribution of the number of customers for a queueing system in which Poisson arrivals are bulks of random size. The number of customers per bulk varies randomly between 1 and m, m arbitrary, according to a point multinomial, and customer service is exponential. Queue characteristics are given.
On the aggregation of preferences
Authors: Rödding Walburga , Nachtkamp Hans H.
Published: May 2007

The article attempts to show how network theory may be applied to gain new and better insights into basic economic problems. Starting with a precise definition of what is meant by acting and, in particular, by economic acting, we direct the line of argumentation toward solving the problem of how to aggregate economic decisions. Results indicate that network theory might well prove itself to be a powerful instrument in developing a theory of human behavior much more comprehensive than currently used models.
Weibull tolerance intervals associated with moderate to small survival proportions for use in a new formulation of lanchester combat theory
Authors: Mann Nancy R.
Published: May 2007

Given herein is an easily implemented method for obtaining, from complete or censored data, approximate tolerance intervals associated with the upper tail of a Weibull distribution. These approximate intervals are based on point estimators that make essentially most efficient use of sample data. They agree extremely well with exact intervals (obtained by Monte Carlo simulation procedures) for sample sizes of about 10 or larger when specified survival proportions are sufficiently small. Ranges over which the error in the approximation is within 2 percent are determined.

The motivation for investigation of the methodology for obtaining the approximate tolerance intervals was provided by the new formulation of Lanchester Combat Theory by Grubbs and Shuford [3], which suggests a Weibull assumption for time‐to‐incapacitation of key targets. With the procedures investigated herein, one can use (censored) data from battle simulations to obtain confidence intervals on battle times associated with given low survivor proportions of key targets belonging to either specified side in a future battle. It is also possible to calculate confidence intervals on a survival proportion of key targets corresponding to a given battle duration time.
A mathematical programming approach to the scheduling of sorting operations
Authors: Murphy Frederic H. , Stohr Edward A.
Published: May 2007

In this paper we describe an approach to the scheduling and/or real‐time control of sorting operations in the presence of deadlines. The problem arises in the postal service where mail has to be sorted by zip codes, and in the banking system where checks have to be sorted according to the bank on which they are drawn. In both applications losses are incurred if items miss their clearing deadlines. For example, in check‐sorting an extremely important objective of the control system is to reduce the “float” i.e., the total dollar value of the checks which miss their deadlines. The proposed real‐time control system utilizes a linear program which chooses between alternative sort‐patterns and assigns the various processing steps to the time periods between deadlines.
On convexity proofs in location theory
Authors: Love Robert F. , Morris James G.
Published: May 2007

It is often assumed in the facility location literature that functions of the type øi(xi, y) = βi[(xi‐x)2+(yi‐y)2]K/2 are twice differentiable. Here we point out that this is true only for certain values of K. Convexity proofs that are independent of the value of K are given.
A recursive algorithm for a summed multinomial density function
Authors: Fink Raymond K. , Moskowitz Herbert
Published: May 2007

An algorithm for calculating the probabilities of a summed multinomial density function which is recursive with n (the number of trials) is presented. Having application in inspector error models for auditing and quality control problems with Cartesian product structures, the algorithm is discussed in the context of computing optimal economic sampling plans. Computational experience with the algorithm is presented.
Multiple‐attribute decision making with partial information: The comparative hypervolume criterion
Authors: Charnetski Johnnie R. , Soland Richard M.
Published: May 2007

A new approach is presented for analyzing multiple‐attribute decision problems in which the set of actions is finite and the utility function is additive. The problem can be resolved if the decision makers (or group of decision makers) specifies a set of nonnegative weights for the various attributes or criteria, but we here assume that the decision maker(s) cannot provide a numerical value for each such weight. Ordinal information about these weights is therefore obtained from the decision maker(s), and this information is translated into a set of linear constraints which restrict the values of the weights. These constraints are then used to construct a polytope W of feasible weight vectors, and the subsets Hi (polytopes) of W over which each action ai has the greatest utility are determined. With the Comparative Hypervolume Criterion we calculate for each action the ratio of the hypervolume of Hi to the hypervolume of W and suggest the choice of an action with the largest such ratio. Justification of this choice criterion is given, and a computational method for accurately approximating the hypervolume ratios is described. A simple example is provided to evaluate the efficiency of a computer code developed to implement the method.
Solution of continuous‐time markovian decision models using infinite linear programming
Authors: Kakumanu Prasadarao
Published: May 2007

Infinite‐horizon, countable‐state, continuous‐time Markovian decision models are solved by formulating as a pair of infinite linear‐programming problems. Expected discounted and average returns are considered as criterion functions. For both criterion functions, the existence of deterministic optimal stationary policies is established by solving the associated infinite linear‐programming problems. Computational procedures for finite state and action sets are discussed by considering associated finite linear‐programming problems.
Renewal processes of phase type
Authors: Neuts Marcel F.
Published: May 2007

This paper discusses a class of analytically and numerically tractable renewal processes, which generalize the Poisson process. When used to describe interarrival or service times in queues, these renewal processes lead to computationally explicit solutions which involve only real arithmetic. Previous modifications of the Poisson process, based on the Erlang or the hyperexponential distributions, appear as particular cases.
A home rule puzzle
Authors: Tollenaar Kenneth C.
Published: May 2007

Metropolitan area functional consolidation calls for modification of established theory.
How the vote is bought
Authors: Legislator Kentucky
Published: May 2007

It isn't rascally politicians who corrupt, it's the citizens who are eager to sell their votes.
New urban challenge
Authors: Leach Richard H.
Published: May 2007

Local leaders urged to take responsibility for finding metropolitan problem solutions.
Rebirth of philadelphia
Authors: Havemann Ernest
Published: May 2007

City is living proof of what citizens can do to secure good government, civic renaissance.
Cradle of liberty
Authors: O'Hare Robert J. M.
Published: May 2007

Massachusetts, rich in tradition of freedom, lags far behind in granting local home rule.
For tomorrow's voter
Authors: Mueller Donald E. , Benninghoven Donald C.
Published: May 2007

Californians tackling problem of beefing up high school courses in municipal government.
An unconditionally convergent algorithm for the evaluation of the ultimate limit state of RC sections subject to axial force and biaxial bending
Authors: Alfano G. , Marmo F. , Rosati L.
Published: May 2007

We present a numerical procedure, based upon a tangent approach, for evaluating the ultimate limit state (ULS) of reinforced concrete (RC) sections subject to axial force and biaxial bending. The RC sections are assumed to be of arbitrary polygonal shape and degree of connection; furthermore, it is possible to keep fixed a given amount of the total load and to find the ULS associated only with the remaining part which can be increased by means of a load multiplier. The solution procedure adopts two nested iterative schemes which, in turn, update the current value of the tentative ultimate load and the associated strain parameters. In this second scheme an effective integration procedure is used for evaluating in closed form, as explicit functions of the position vectors of the vertices of the section, the domain integrals appearing in the definition of the tangent matrix and of the stress resultants. Under mild hypotheses, which are practically satisfied for all cases of engineering interest, the existence and uniqueness of the ULS load multiplier is ensured and the global convergence of the proposed solution algorithm to such value is proved. An extensive set of numerical tests, carried out for rectangular, L‐shaped and multicell sections shows the effectiveness of the proposed solution procedure. Copyright © 2007 John Wiley & Sons, Ltd.
Cholestasis is a marker for hepatocellular carcinomas displaying β‐catenin mutations
Authors: Audard V , Grimber G , Elie C , Radenen B , Audebourg A , Letourneur F , Soubrane O , Vacher‐Lavenu M‐C , Perret C , Cavard C , Terris B
Published: May 2007

The Wnt/β‐catenin signalling pathway is activated in many human hepatocellular carcinomas (HCC). Identification of β‐catenin mutation relies mostly on sequence analysis and/or immunohistochemistry. β‐catenin mutation may also be detected by analysing the expression of its target genes. The GLUL gene encoding glutamine synthetase (GS), for example, appears to be a pertinent marker. The aim of this study was to correlate GS immunostaining and β‐catenin mutations with clinicopathological features in HCC. We found that GS immunostaining had a sensitivity of 90% for the detection of β‐catenin mutations, with 98% specificity, whereas β‐catenin immunostaining had a sensitivity of 63% with 98% specificity. We used the sensitive GS marker to characterize 190 HCC cases. Sixty‐eight (36%) cases displayed Wnt/β‐catenin activation. In addition to their well‐differentiated pattern, these tumours exhibited significant features such as a homogeneous microtrabeculo‐acinar pattern, low‐grade cellular atypia, and cholestasis. As these tumours exhibited cholestasis, we hypothesized that β‐catenin acts on specific bile synthesis and/or transport pathways. In conclusion, we propose that GS immunostaining and a cholestatic pattern are relevant criteria for the identification of HCC with β‐catenin mutations. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Investigation of water absorption in pultruded composites containing fillers and low profile additives
Authors: Ben Daly H. , Ben Brahim H. , Hfaied N. , Harchay M. , Boukhili R.
Published: May 2007

This work investigates the humidity absorption process in the polyester/glass fiber composite materials containing fillers and low profile additives. These composite materials were exposed to both distilled and sea water at different temperatures. The moisture diffusivity and the moisture equilibrium reached by these composites were determined using the gravimetric test method and their humidity distribution profile across the thickness direction was characterized using the microtome technique. The obtained results indicate that the distilled water diffuses in all composites much more rapidly than the sea water, particularly at high immersion temperatures. However, the opposite is observed at low immersion temperature (5°C), since at this temperature the distilled water is almost in its icy state. For high immersion temperatures, a mass loss of the aged specimen in the sea water was observed 2 months after the first immersion. Such behavior was not observed during the immersion in the distilled water. Moreover, it is observed that the water absorption is higher in the composite materials containing low profile additives. This behavior is explained in terms of microvoids formation promoted by low profile additives. The microtome technique reveals clearly that the humidity profile across the thickness of the aged specimen follows a parabolic trend with a maximum at the outside surface of that specimen and a minimum at its center. These experimental results were found to confirm the theory. POLYM. COMPOS., 28: 355–364, 2007. © 2007 Society of Plastics Engineers