bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of Product Specifications for Multi-Characteristic Inspection
Authors: Tang Kwei , Tang Jen
Published: November 2008

A product often requires inspection on more than one characteristic. The traditional method determines inspection specifications for each characteristic independently. This practice ignores the interactions among characteristics in determining the disposition of an item, and prohibits tradeoffs among the quality of characteristics. In this paper, two multi-characteristic screening (complete inspection) models are proposed with different information processing requirements. In both models, screening specifications are jointly determined by considering all the economic and stochastic factors associated with the characteristics of interest. However, in Model 1, each characteristic has separate screening specifications and the inspection results of conformance (acceptance or rejections) of all the characteristics are used to determine the disposition of an item. In the second model, a joint screening rule based on an aggregation of characteristics is used to allow direct tradeoffs among the quality of characteristics. To implement the second model, the exact measured values of all characteristics of an item have to be recorded and used for a decision on that item. These two models are formulated and the solution procedures are developed. A numerical study is used to compare the cost performance and other plan characteristics of the independently-determined single characteristic models and the two multi-characteristic models.
On Optimal Production and the Market to Book Ratio Given Limited Shareholder Diversification
Authors: Conine Thomas E. , Jensen Oscar W. , Tamarkin Maurry
Published: November 2008

Our purpose is to examine a firm's optimal output decision and valuation when its shareholders hold a limited number of risky assets. The primary theoretical result indicates that the market-to-book ratio is a function of the degree of shareholder diversification. Our theory suggests a negative relationship between a firm's market-to-book ratio and shareholder diversification.
Preference Structure Representation Using Convex Cones in Multicriteria Integer Programming
Authors: Ramesh R. , Karwan Mark H. , Zionts Stanley
Published: November 2008

A new efficient system of representing the decision-maker's preference structure in solving multicriteria integer programming problems is developed. The problem is solved by an interactive branch-and-bound method that employs the procedure of Zionts and Wallenius (Zionts, S., J. Wallenius. 1983. An interactive multiple objective linear programming method for a class of underlying nonlinear utility functions. Management Sci. 29(5).) for multicriteria linear programming. The decision-maker's underlying utility function is assumed to be pseudoconcave, and his pairwise comparisons of decision alternatives are used to determine his preference structure in terms of certain convex cones in the objective function space and constraints on the weights on the objectives in the weight space. The two forms of preference structure representation are interrelated, and their underlying theory is developed. The primary objective of a representation scheme is exactness, and, in this respect, it is shown that the constraints on the weights are not adequate for representing nonlinear utility functions. On the other hand, the convex cones exactly represent any quasiconcave utility function and clearly avoid the approximations and inaccuracies in other utility assessment systems. Accordingly, an efficient ordered representation using convex cones is developed. An algorithmic framework for multicriteria integer programming that integrates the representation using convex cones with the branch-and-bound solution procedure is developed. Computational experience with bicriteria problems having up to 80 variables and 40 constraints is presented.
On Estimating Skewness in Stock Returns
Authors: Lau Hon-Shiang , Wingender John R. , Lau Amy Hing-Ling
Published: November 2008

In recent years skewness has become a much-discussed factor in financial research, and many studies/models involve the skewness of various financial variables. This paper (i) points out the universal neglect in the finance literature of skewness' sampling error and its significant consequences; (ii) presents a simple approach for roughly constructing a confidence interval for skewness estimated from lognormal populations; (iii) points out directions of further research for developing a comprehensive approach for estimating skewness reliably.
Uncapacitated Plant Location Under Alternative Spatial Price Policies
Authors: Hanjoul Pierre , Hansen Pierre , Peeters Dominique , Thisse Jacques-Francois
Published: November 2008

Given a spatial system of clients' demand functions, this paper proposes solution methods to determine the price(s), the number, the locations, the sizes, and the market areas of the plants supplying the clients in order to maximize the profit of the firm. Three alternative spatial price policies are considered: (i) uniform mill pricing, in which the same price is charged to the clients at the plant door, (ii) uniform delivered pricing, in which clients pay the same delivered price irrespective of their locations, and (iii) spatial discriminatory pricing, which is such that the firm sets client-specific prices based on their locations. Computational results are reported.
One Warehouse Multiple Retailer Systems with Vehicle Routing Costs
Authors: Anily S. , Federgruen A.
Published: November 2008

We consider distribution systems with a depot and many geographically dispersed retailers each of which faces external demands occurring at constant, deterministic but retailer specific rates. All stock enters the system through the depot from where it is distributed to the retailers by a fleet of capacitated vehicles combining deliveries into efficient routes. Inventories are kept at the retailers but not at the depot.

We wish to determine feasible replenishment strategies (i.e., inventory rules and routing patterns) minimising (infinite horizon) long-run average transportation and inventory costs. We restrict ourselves to a class of strategies in which a collection of regions (sets of retailers) is specified which cover all outlets: if an outlet belongs to several regions, a specific fraction of its sales/operations is assigned to each of these regions. Each time one of the retailers in a given region receives a delivery, this delivery is made by a vehicle who visits all other outlets in the region as well (in an efficient route).

We describe a class of low complexity heuristics and show under mild probabilistic assumptions that the generated solutions are asymptotically optimal (within the above class of strategies). We also show that lower and upper bounds on the system-wide costs may be computed and that these bounds are asymptotically tight under the same assumptions. A numerical study exhibits the performance of these heuristics and bounds for problems of moderate size.
Strategy, Complexity, and Economic Rent
Authors: Schoemaker Paul J. H.
Published: November 2008

This paper discusses important friction forces that future theories of strategy must incorporate. Some of these are technological and environmental; but the most important ones—it is argued—are psychological. The view is developed that strategy, at its core, concerns the development and testing of heuristics for high stake decisions in environments too unstable and complex to be optimized.

The paper especially highlights the behavioral dimension, in the belief that strategies should incorporate both the rational and suboptimal aspects of human behavior. The rational approach is in many ways the easier, as there may be only one way to be right. Yet, the great variety in which people and companies can err gives strategy its creative and real-world challenge. The tension between the rational and behavioral components is what the field of strategy should seek to exploit.
Broader Product Line: A Necessity to Achieve Success?
Authors: Kekre Sunder , Srinivasan Kannan
Published: November 2008

Strategic product line breadth decisions evoke differential responses from the manufacturing and the marketing areas: manufacturing prefers keeping process disruptions to a minimum and, as a result, discourages product proliferation; however, marketing, in its attempt to match products to heterogeneous consumer needs and gain market share, emphasizes a broader product line. We systematically investigate the market benefits and cost disadvantages of broader product lines on a large sample of over 1,400 business units. Our results indicate significant market share benefits and increases in firms' profitability with broader product lines; moreover, widely held beliefs of increases in production costs are not empirically supported. American manufacturing firms may indeed be flexible enough to accommodate product variety without significant detrimental effects on costs.
Management, Strategy, and Industry Structure As Influences on the Success of New Firms: A Structural Model
Authors: Keeley Robert H. , Roure Juan B.
Published: November 2008

This study develops and tests a model examining the interrelationships and relative importance of management characteristics, business strategy and industry structure as influences on the performance of new, technology based companies. For a sample of 36 companies the founding managers had a sizeable influence on the quality of the industry/strategy positions, though exogenous forces were even more important; and regardless of source, industry/strategy positions exerted important influence on performance. Management characteristics influenced success through implementation, in addition to their influence on industry/strategy.

The study demonstrates the effect of the founding managers on the eventual performance of a new venture. It suggests that formulation of the initial concept and execution of that concept call upon different characteristics, and therefore may be separable. That is, one group might initially devise the plan and another carry it out.
Output Decision Under Demand Uncertainty with Stochastic Production Function: A Contingent Claims Approach
Authors: Chung Kee H.
Published: November 2008

This paper presents a contingent claims analysis of output decisions for the firm facing technological and demand uncertainty. The paper reveals that: (i) the optimal output level increases with the higher interest rate when the firm is subject to demand (and technological) uncertainty; (ii) the effect of demand volatility and production lead time on the optimal output level could be either positive or negative; (iii) the optimal project value decreases with the higher demand volatility; (iv) the optimal project value decreases with the longer production lead time when the firm is subject to demand uncertainty; and (v) the optimal project value decreases with the higher interest rate when the firm is subject to demand uncertainty; it increases with the higher interest rate, however, when the firm is subject to both demand and technological uncertainty. Some important managerial implications are discussed.
Tax-Adjusted Discount Rates
Authors: Sick Gordon A.
Published: November 2008

This paper develops models for discount rates that are adjusted for the interest tax shields of an infra-marginal firm in a general tax equilibrium where there is cross-sectional variation in corporate tax rates. Under the assumption that the firm optimally maintains a predetermined debt ratio, a tax-adjusted riskless discount rate model is given for valuing certainty-equivalents and a tax-and-risk-adjusted discount rate model is given for valuing expected cash flows. For the latter case, the asset, equity, debt and tax-shield betas are derived and a weighted average cost of capital interpretation is given. The tax-adjusted CAPM/APT security market lines for expected returns in stock and bond markets both have the same slope but different intercepts. A formula is also provided for the present value of the interest tax shield when the firm optimally maintains a predetermined debt level.

The analysis here also differs from the existing literature in the following respects: It allows for cross-sectional variation in corporate tax rates and personal tax rates. It shows that the market values of risky and riskless interest tax shields differ only to the extent that tax laws provide for nonlinear taxation of gains and losses. It also shows that interest tax shields should be discounted at a tax-adjusted discount rate that reflects the fact that they accrue to equity investors, rather than debt investors. Continuous-time simplifications of the formulas in this paper and the previous literature are also given.
Adjusting Replenishment Orders to Reflect Learning in a Material Requirements Planning Environment
Authors: Dolinsky Larry R. , Vollmann Thomas E. , Maggard Michael J.
Published: November 2008

Some manufacturing firms, particularly in the high-technology sector, have production processes which are characterized by very low initial yields followed by steady “experience” based yield improvement. Material Requirements Planning literature reveals that MRP implementations are seldom adjusted in any systematic way to account for such yield improvement. A single product, single stage MRP model is developed which incorporates learning curve behavior into conventional MRP logic. A series of experiments systematically examine the impact on mean inventory level of various combinations of environmental conditions and managerial policies. The research demonstrates that substantial reductions in mean inventory levels can be realized in low yield environments if learning is properly included in the order release logic. This finding proves to be robust with respect to modest errors in the estimation of learning rate.
Routing and Scheduling on a Shoreline with Release Times
Authors: Psaraftis Harilaos N. , Solomon Marius M. , Magnanti Thomas L. , Kim Tai-Up
Published: November 2008

In this paper we examine computational complexity issues and develop algorithms for a class of “shoreline” single-vehicle routing and scheduling problems with release time constraints. Problems in this class are interesting for both practical and theoretical reasons. From a practical perspective, these problems arise in several transportation environments. For instance, in the routing and scheduling of cargo ships, the routing structure is “easy” because the ports to be visited are usually located along a shoreline. However, because release times of cargoes at ports generally complicate the routing structure, the combined routing and scheduling problem is nontrivial. For the straight-line case (a restriction of the shoreline case), our analysis shows that the problem of minimizing the maximum completion time can be solved exactly in quadratic time by dynamic programming. For the shoreline case we develop and analyze heuristic algorithms. We derive data-dependent worst-case performance ratios for these heuristics that are bounded by constant. We also discuss how these algorithms perform on practical data.
Note—New Confidence Interval Estimators Using Standardized Time Series
Authors: Goldsman David , Schruben Lee
Published: November 2008

We develop new asymptotically valid confidence interval estimators (CIE's) for the underlying mean of a stationary simulation process. The new estimators are weighted generalizations of Schruben's standardized time series area CIE. We show that the weighted CIE's have the same asymptotic expected length and variance of the length as the area CIE; but in the small sample environment, the new CIE's exhibit performance characteristics which are different from those of the area CIE.
Conflict in Organizational Decision Making: An Exploratory Study of Its Effects in For-Profit and Not-For-Profit Organizations
Authors: Schwenk Charles R.
Published: November 2008

Though past research has shown that conflict may improve organizational decision making, business executives may have very different perceptions of the effects of conflict than executives of not-for-profit organizations. This exploratory study deals with executives' descriptions of the effects of conflict on their own organizations' decisions. Results show that high conflict is associated with high quality for the executives of not-for-profit organizations but with low quality for executives of for-profit organizations. Analysis of executives' written descriptions of these decisions suggests some reasons for this difference.
Some Heuristics for Scheduling Jobs on Parallel Machines with Setups
Authors: So Kut C.
Published: November 2008

This paper studies the problem of scheduling jobs on parallel machines with setup times. When a machine switches from processing one type of job to another type, setup times are incurred. The problem is to find a feasible schedule for each machine which maximizes the total reward. We study three heuristics for solving this problem. Analytical and empirical results of the heuristics are given.
Note—Derivation of Covariance Probit Elasticities
Authors: Hofacker Charles F.
Published: November 2008

The full covariance probit model is highly regarded due to the flexibility with which it can represent cross brand effects. Explicit formulae for these cross brand effects for the general N brand case have never appeared in print, nor have the direct elasticities for the model. This note fills that omission.
Note—A Branch-and-Fathom Algorithm for the Long Range Process Design Problem
Authors: Singhal Jaya , Katz Joseph L.
Published: November 2008

Several problems, including the long-range process design problem, have been formulated as a compatibility matrix. Earlier, Singhal et al. (1988) proposed a partial enumeration algorithm which found all feasible designs and reported computational results. However, for large problems, the partial enumeration algorithm requires an excessive amount of computational effort to locate all feasible designs. This paper presents a branch and fathom algorithm which is more efficient than the partial enumeration algorithm, and which significantly reduces the computational effort necessary to identify all feasible designs.
Properties of Standardized Time Series Weighted Area Variance Estimators
Authors: Goldsman David , Meketon Marc , Schruben Lee
Published: November 2008

We wish to estimate the variance of the sample mean from a continuous-time stationary stochastic process. This article expands on the results of a technical note (Goldsman and Schruben 1990) by using the theory of standardized time series to investigate weighted generalizations of Schruben's area variance estimator. We find a simple expression for the bias of the weighted area variance estimator, and we give weights which yield variance estimators with lower asymptotic bias than certain other popular estimators.

We use the weighted area variance estimators to derive asymptotically valid confidence interval estimators (CIEs) for the mean of a stationary stochastic process. Although the weighted area CIEs have the same asymptotic expected value and variance of the length as Schruben's area CIE, we show that the new CIEs sometimes yield coverages which are closer to the nominal value.
Performance of Shortest Path Algorithms in Network Flow Problems
Authors: Divoky James J. , Hung Ming S.
Published: November 2008

It is known that minimum cost flow problems can be solved by successive augmentations along shortest paths. In this paper the issues of implementing shortest path algorithms in this context are examined. Of particular interest is the dynamic topology that the flow networks exhibit. We develop a network generator capable of emulating such topology. Strategies for exploiting the special structures in such networks are discussed. A set of 9000 test problems is offered, from which a particular strategy/algorithm combination is shown to consistently produce superior results when compared to the other combinations.
Optimal Solution of Set Covering/Partitioning Problems Using Dual Heuristics
Authors: Fisher Marshall L. , Kedia Pradeep
Published: November 2008

We present an algorithm for a mixed set covering/partitioning model that includes as special cases the well-known set covering problem and set partitioning problem. The novel feature of our algorithm is the use of continuous heuristics applied to the dual of the linear programming relaxation to provide lower bounds for a branch and bound algorithm. The heuristics are continuous adaptations of the well-known greedy and 3-opt methods that have been applied to a variety of combinatorial optimization problems. Our algorithm has outperformed the current best set covering algorithm of Balas and Ho (1980) by about a factor of 3, and appears to improve on the best existing set partitioning algorithm by more than an order of magnitude.
A Model of New Product Development: An Empirical Test
Authors: Zirger Billie Jo , Maidique Modesto A.
Published: November 2008

This paper reports on the culmination of a four year study of high technology product innovation. During the course of this research, we examined over 330 new products in the electronics industry in order to better understand the factors that differentiated successful from unsuccessful product development efforts.

This paper presents the conclusions from the final phase of the research. In this study we empirically test a model of product development that incorporates our findings from the earlier exploratory survey and case study phases of our research. The model identifies the critical organizational subunits, development activities and communication channels that influence product outcome, as well as, external factors such as characteristics of the product and the competitive environment.

Our findings suggest the following key factors affect product outcome: (1) the quality of the R&D organization, (2) the technical performance of the product, (3) the product's value to the customer, (4) the synergy of the new product with the firm's existing competences, and (5) management support during the product development and introduction processes. Also important but less significant were the (6) competence of the marketing and manufacturing organizations and market factors, such as the (7) competitiveness and the (8) size and rate of growth of the target market.
Database Models and Managerial Intuition: 50% Model + 50% Manager
Authors: Blattberg Robert C. , Hoch Stephen J.
Published: November 2008

We focus on ways of combining simple database models with managerial intuition. We present a model and method for isolating managerial intuition. For five different business forecasting situations, our results indicate that a combination of model and manager always outperforms either of these decision inputs in isolation, an average R2 increase of 0.09 (16%) above the best single decision input in cross-validated model analyses. We assess the validity of an equal weighting heuristic, 50% model + 50% manager, and then discuss why our results might differ from previous research on expert judgment.
Accumulation Point Location on Tree Networks for Guaranteed Time Distribution
Authors: Iyer Ananth V. , Ratliff H. Donald
Published: November 2008

A guaranteed time distribution system is organized so that movement of items between any source-destination pair (serviced by the system) is completed within a guaranteed period of time (T). Various express mail services are examples of such distribution systems. The movement of items between source and destination consists of a combination of different modes of travel with varying speeds (i.e. trucks, airplanes etc.). Decisions have to be made regarding location of accumulation points (called local centers) at which changes in the mode of travel occur. All customers have to be allocated to these local centers so as to provide the best (minimum) time guarantee for travel between every source-destination pair. Accumulated flows between local centers pass through a global center in a centralized sorting system (CSS) and move directly between local centers in a decentralized sorting system (DSS). For tree structured distribution systems we provide polynomial time algorithms that locate a given number of local centers, allocate customers to local centers and provide the best possible time guarantee for both centralized and decentralized guaranteed time distribution systems.
Shared Storage Policies Based on the Duration Stay of Unit Loads
Authors: Goetschalckx Marc , Ratliff H. Donald
Published: November 2008

This paper addresses duration-of-stay-based shared storage policies for a unit load warehouse. We show that, for single command storage and retrieval, shared storage policies based on duration of stay of individual unit loads have the potential to significantly decrease travel time. An optimal storage policy with respect to travel time and storage space is developed for systems with balanced input and output. Based on the same principles, two heuristic policies are developed for more complex systems. Simulation results are provided which compare travel times for dedicated storage, random storage, turnover-based storage classes, and duration-of-stay-based storage classes.
Solving Multi-Item Lot-Sizing Problems Using Strong Cutting Planes
Authors: Pochet Yves , Wolsey Laurence A.
Published: November 2008

We consider two classes of multi-item lot-sizing problems. The first is a class of single stage problems involving joint machine capacity constraints and/or start up costs, and the second is a class of multistage problems with general product structure.

The problems are solved as mixed integer programs based on (i) an appropriate choice of the initial problem formulation and (ii) the addition of cuts which are generated automatically by a mathematical programming system (MPSARX). Our results extend and complement those of Karmarkar and Schrage (1985), Afentakis and Gavish (1986), Eppen and Martin (1987) and Van Roy and Wolsey (1987). A major advantage of this approach is its robustness or flexibility. By using just a matrix generator and a mathematical programming system with automatic cut generation routines we can formulate and solve model variants without incurring the costs of adapting an algorithm.
Constructing School Timetables Using Simulated Annealing: Sequential and Parallel Algorithms
Authors: Abramson D.
Published: November 2008

This paper considers a solution to the school timetabling problem. The timetabling problem involves scheduling a number of tuples, each consisting of class of students, a teacher, a subject and a room, to a fixed number of time slots. A Monte Carlo scheme called simulated annealing is used as an optimisation technique. The paper introduces the timetabling problem, and then describes the simulated annealing method. Annealing is then applied to the timetabling problem. A prototype timetabling environment is described followed by some experimental results. A parallel algorithm which can be implemented on a multiprocessor is presented. This algorithm can provide a faster solution than the equivalent sequential algorithm. Some further experimental results are given.
Interactive Process Quality Improvement
Authors: Marcellus Richard L. , Dada Maqbool
Published: November 2008

An ongoing production process produces defective parts at random intervals. Each defective part provides a learning opportunity which the decision maker may use to improve the process by investing resources to identify and remove the causes of the defective. For various cost criteria, it is optimal to invest in learning until the probability of producing a defective becomes sufficiently small. This policy has economic interpretations in terms of marginal benefits. In addition, the optimal policy for expected discounted present cost has an interpretation in terms of tradeoffs between “cost of failure” and “cost of prevention”. The shape of the tradeoff curve gives insight into the controversy between the traditional and zero defects views towards cost of quality.
Business Risk and Return: A Test of Simultaneous Relationships
Authors: Oviatt Benjamin M. , Bauerschmidt Alan D.
Published: November 2008

Bowman (1980) found an unexpected and paradoxical negative relationship between risk and return in many firms, and, for about a decade, various researchers have attempted to explain the paradox. This article summarizes some of those explanations, and shows that industry conditions and business strategies are likely to influence both risk and return. The relationships are depicted in a simultaneous model where business return, risk, and debt are endogenously determined.

The model is tested with 132 nondiversified firms in 8 disparate industries. OLS estimates of the parameters of the model show the risk-return relationship to be significantly negative, as many past researchers have found. However, 3SLS estimates of the parameters of the simultaneous model reveal no significant relationship between risk and return. The tentative conclusion is that many of the studies in the line of research concerned with Bowman's (1980) paradox may have used an improperly specified model, and that when a more realistic simultaneous model is used, return and risk are shown to be influenced by various industry conditions and business strategies, but not by each other.
Multiple Market Entry, Cost Signalling and Entry Deterrence
Authors: Srinivasan Kannan
Published: November 2008

A low-cost incumbent may limit price to informatively signal her cost to an uncertain potential entrant, and therefore deter entry. We enrich this model by investigating the strategic pricing behavior of the incumbent when she operates in multiple markets. We demonstrate that the low-cost incumbent's ability to separate from a ghost high-cost type is enhanced when she combines her signalling effort across markets, instead of independent signalling in each market. We show that, in the combined least-cost signalling, the low-cost incumbent limit prices in each market. In an attempt to minimize dissipative but informative signalling costs, the low-cost incumbent may enter unprofitable markets, but exit after credible separation.
Resource-Use Efficiency in Public Schools: A Study of Connecticut Data
Authors: Ray Subhash C.
Published: November 2008

This study combines Data Envelopment Analysis (DEA) with regression modelling to estimate relative efficiency in the public school districts of Connecticut. Factors affecting achievements are classified as school inputs and other socio-economic factors. DEA is performed with the school inputs only. Efficiency measures obtained from DEA are subsequently related to the socio-economic factors in a regression model with a one-sided disturbance term. The findings suggest that while productivity of school inputs varies considerably across districts this can be ascribed to a large extent to differences in the socio-economic background of the communities served. Variation in managerial efficiency is much less than what is implied by the DEA results.
Optimal Sequencing and Resource Allocation in Research and Development Projects
Authors: Granot Daniel , Zuckerman Dror
Published: November 2008

The main purpose of this study is to construct a suitable research and development (R&D) model which would facilitate the analysis of activity sequencing and resource allocation in R&D projects. In the proposed model, essential characteristics of R&D projects are incorporated. Namely, the activities and the technological specifications of the project are selected dynamically, and the stopping time of the R&D process is introduced as a decision variable to be determined endogeneously. We characterize the collection of optimal sequencing of R&D activities that would maximize the expected net present value of the project, and we evaluate the possibility of incorporating various learning aspects into the model. We further analyze a resource allocation problem associated with the R&D model. It is shown that in certain cases one can efficiently implement a greedy-optimal resource allocation procedure for increasing the expected net present value of the R&D project.
Storing Crossmatched Blood: A Perishable Inventory Model with Prior Allocation
Authors: Jagannathan Raj , Sen Tarun
Published: November 2008

The process of testing a sample of a patient's blood against units of blood from inventory to ensure compatibility is called crossmatching. When a physician orders blood, it is crossmatched and then held for a patient. As a precautionary measure, physicians tend to order blood in excess of the amount that is transfused (used by the patient). Consequently, a large proportion of blood held for a patient (often higher than 50 percent) is eventually not transfused. This leads to increased outdates. The effects of crossmatching on outdates are widely acknowledged, but have seldom been included in blood inventory control models. In this paper, we develop a model for determining outdates and shortages for crossmatched blood using generally accepted parameters, such as proportion of crossmatched blood that is actually transfused, and the number of days after which crossmatched blood is released if not transfused. This model can be used as a decision support system that allows the blood bank administrator to do sensitivity analyses related to controllable blood inventory parameters.
Approximations for Networks of Queues with Overtime
Authors: Bitran Gabriel R. , Tirupati Devanath
Published: November 2008

This paper presents simple approximations for networks of queues with overtime operation at some stations. This type of network is commonly encountered in several manufacturing applications. We provide bounds on the performance of the approximations for single and multiple machine stations. Our results suggest that the methods perform satisfactorily. These approximations can be used in conjunction with parametric decomposition methods to analyze queueing networks. The computational results indicate that the performance of the decomposition approach does not deteriorate when combined with the methods proposed in this paper.
Variance Effects in Cyclic Production Systems
Authors: Sarkar Debashish , Zangwill Willard I.
Published: November 2008

Utilizing a cyclic queue system, this paper investigates the effect of variance on a multi-item production facility. The variance of setup time, service rate and arrival rate is shown to have a powerful and sometimes paradoxical influence. Reduction in setup time, for example, is usually presumed to reduce inventory. We demonstrate that inventory can blow up if setup time is cut. Another paradoxical effect of variance is on processing rate. Speeding up the processing rate should reduce the material waiting to be processed. Again we show that the opposite can hold. Other properties of variance are examined, such as its relationship to KAIZEN and Just-In-Time production practices, and especially its property of impairing capacity.
Optimizing Processing Rates for Flexible Manufacturing Systems
Authors: Schweitzer Paul J. , Seidmann Abraham
Published: November 2008

This paper introduces the generic concept of processing rates as decision variables in Flexible Manufacturing Systems (FMS's). The objective is to determine the minimum cost processing rates given the FMS throughput target, the work-in-process level, part routes, transporter delays, and the variable capacity cost function for each machine. A nonlinear Mean Value Analysis queueing network optimization methodology is developed to control bottlenecks and queue lengths as the processing rates are varied. This methodology further provides the average and marginal unit production costs along with necessary and sufficient feasibility conditions for the FMS throughput targets. Industrial sample data is then used to illustrate the solution of the optimal tool speed problem in a metal-cutting FMS. Considerable cost savings are demonstrated using the proposed methodology in contrast with the conventional one-machine optimization models. Several economic insights regarding the issues of capacity allocation for FMS's, and a generalization of the square root capacity allocation rule for closed networks of queues, are also presented.
The Transaction Costs Theory of Joint Ventures: An Empirical Study of Japanese Subsidiaries in the United States
Authors: Hennart Jean-François
Published: November 2008

This paper offers the first large sample empirical study of the factors which influence the choice of Japanese firms between full or partial ownership of their U.S. manufacturing subsidiaries. It studies for the first time the ownership policies of investors of a single home country in a single host country, thus keeping variations within home and host countries constant. One methodological improvement over previous studies is the use as independent variables of the relevant characteristics of the investing firms. These had been proxied in previous studies by data on U.S. industries entered.

The results suggest that the degree of ownership taken by Japanese manufacturing investors in their American subsidiaries is driven by the same general transaction costs variables that determine the choices made by their U.S. counterparts: Japanese parents joint venture when they need to combine with other firms intermediate inputs which are subject to high market transaction costs. An intriguing result, however, is the lack of significance of two variables which, in the U.S. case, strongly push towards full control of foreign subsidiaries. In this study neither the Japanese parent's R&D nor its advertising intensities had any significant impact on their ownership policies.
Sequencing to Minimize Work Overload in Assembly Lines with Product Options
Authors: Yano Candace Arai , Rachamadugu Ram
Published: November 2008

We address the problem of sequencing jobs, each of which is characterized by one of a large number of possible combinations of customer-specified options, on a paced assembly line. These problems arise frequently in the automotive industry. One job must be launched into the system at equal time intervals, where the time interval (or cycle time) is prespecified. The problem is to sequence the jobs to maximize the total amount of work completed, or equivalently, to minimize the total amount of incomplete work (or work overload).

Since there is a large number of option combinations, each job is almost unique. This fact precludes the use of existing mixed model assembly line sequencing techniques. We first consider the sequencing problem for a single station which can perform two different sets of operations. We characterize the optimal solution for this problem and use the results as the basis for a heuristic procedure for multiple stations. Computational results with data from a major automobile company are reported.
Note—Extensions of Palm's Theorem: A Review
Authors: Carrillo Manuel J.
Published: November 2008

This note reviews the transient behavior the M/G/∞ queue with nonhomogeneous Poisson or compound Poisson input and nonstationary service distribution. In the case of nonhomogeneous Poisson input, the number of customers in the queueing system over time turns out to have a Poisson distribution. The generality of the nonhomogeneity/nonstationarity assumptions and the ease of use of the resulting Poisson distribution broaden the area of applications for Poisson models. These results have found use in modeling multi-echelon repair systems in situations where the number of arrivals or number in service has a variance-to-mean ratio of unity (the Poisson case) or greater than unity.
The Impact of Processing Time Knowledge on Dynamic Job-Shop Scheduling
Authors: Wein Lawrence M. , Ou Jihong
Published: November 2008

The goal of this paper is to determine if the results for dynamic job-shop scheduling problems are affected by the assumptions made with regard to the processing time distributions and the scheduler's knowledge of the processing times. Three dynamic job-shop scheduling problems (including a two-station version of Conway et al.'s 1967 nine-station symmetric shop) are tested under seven different scenarios, one deterministic and six stochastic, using computer simulation. The deterministic scenario, where the processing times are exponential and observed by the scheduler, has been considered in many simulation studies, including Conway et al.'s. The six stochastic scenarios include the case where the processing times are exponential and only the mean is known by the scheduler, and five different cases where the machines are subject to unpredictable failures. Two policies were tested, the shortest expected processing time (SEPT) rule, and a rule derived from a Brownian analysis of the corresponding queueing network scheduling problem. Although the SEPT rule performed well in the deterministic scenario, it was easily outperformed by the Brownian policies in the six stochastic scenarios for all three problems. Thus, the results from simulation studies of dynamic, deterministic job-shop scheduling problems may not carry over to the more realistic setting where there is unpredictable variability.
Note—Optimal Inspection Policy in Sequential Screening
Authors: Park June S. , Peters Michael H. , Tang Kwei
Published: November 2008

Under sequential screening, a production lot is inspected item-by-item; the decision is made after inspecting each item whether to inspect another item or to reject the remainder of the lot; and thus uninspected items are never accepted. This screening process is a special case of the sequential sampling considered in Wortham and Wilson (1971). The process is formulated as an optimal stopping problem using a Bayesian approach. Based on an analysis of the structural properties of the optimal policy, a backward-recursive optimal algorithm, which is more efficient than the existing algorithm for optimal sequential sampling, is developed.
A Simple Forward Algorithm to Solve General Dynamic Lot Sizing Models with n Periods in 0(n log n) or 0(n) Time
Authors: Federgruen Awi , Tzur Michal
Published: November 2008

This paper is concerned with the general dynamic lot size model, or (generalized) Wagner-Whitin model. Let n denote the number of periods into which the planning horizon is divided. We describe a simple forward algorithm which solves the general model in 0(n log n) time and 0(n) space, as opposed to the well-known shortest path algorithm advocated over the last 30 years with 0(n2) time.

A linear, i.e., 0(n)-time and space algorithm is obtained for two important special cases: (a) models without speculative motives for carrying stock, i.e., where in each interval of time the per unit order cost increases by less than the cost of carrying a unit in stock; (b) models with nondecreasing setup costs.

We also derive conditions for the existence of monotone optimal policies and relate these to known (planning horizon and other) results from the literature.
Conflict Management in a Computer-Supported Meeting Environment
Authors: Poole Marshall Scott , Holmes Michael , Desanctis Gerardine
Published: November 2008

Computer systems to support decision-making, planning, and negotiation in groups have the potential for wide-ranging application. However, knowledge of their effects is sparse, particularly for difficult situations such as group conflict. This study reports a laboratory experiment to examine how a general purpose group decision support system (GDSS) influenced conflict management in small groups making a budget allocation decision. The study tests a model that posits that GDSS impacts on conflict outcomes are mediated by group interaction processes, particularly how the GDSS enters into group interaction. The model posits seven potential impacts—some positive and some negative—that GDSS technology might have on conflict interaction processes. The impacts do not automatically occur, but depend on the nature of the GDSS and how the group applies it. Hence, a given GDSS might result only in a subset of the seven impacts. Among other things, the model predicts that the particular combination of GDSS impacts that materializes differs across groups and that the balance of these impacts, positive or negative, determines positive or negative conflict outcomes.

Groups using a particular GDSS, the Software Aided Meeting Management (SAMM) system, were compared to groups using a manual version of the same decision structures built into SAMM and to unsupported groups. Results indicated that there were differences in the level of conflict in SAMM-supported versus manually-supported and unsupported groups, and in conflict management behaviors adopted by the different conditions. Moreover, there were differences in the impacts of SAMM for different groups, and there is some evidence that these contributed to consensus change. Overall, the theoretical model was supported by the study. This model and approach used in this study seem useful for designing future studies concerning the impacts of computer technology on group judgment and choice.
Parkinson's Law and Its Implications for Project Management
Authors: Gutierrez Genaro J. , Kouvelis Panagiotis
Published: November 2008

Critical path models concerning project management (i.e. PERT/CPM) fail to account for work force behavioral effects on the expected project completion time. In this paper, we provide a modelling framework for project management activities, that ultimately accounts for expected worker behavior under Parkinson's Law. A stochastic activity completion time model is used to formally state Parkinson's Law. The developed model helps to examine the effects of information release policies on subcontractors of project activities, and to develop managerial policies for setting appropriate deadlines for series or parallel project activities.
Complementary Resources and Cooperative Research: A Model of Research Joint Ventures Among Competitors
Authors: Sinha Deepak K. , Cusumano Michael A.
Published: November 2008

We present a model of research joint ventures in which if firms have highly complementary skills and resources then they prefer to cooperate in areas where the technology is highly appropriable, as in applied research. The model also indicates that large firms have a greater incentive to cooperate because they are better positioned to capture the benefits of a research venture. These findings seem to explain why cooperative research among rival firms in Japan has been applied rather than basic and conducted frequently among large companies. But firms prefer as small a partner as possible to limit the sharing of research results, creating a tension that may make cooperative efforts among rivals difficult to manage. For this reason, cooperation with organizations, such as universities or nonprofit institutions, may be a viable alternative for firms looking for complementary skills and resources.
A Composite Approach to Inducing Knowledge for Expert Systems Design
Authors: Liang Ting-Peng
Published: November 2008

Knowledge acquisition is a bottleneck for expert system design. One way to overcome this bottleneck is to induce expert system rules from sample data. This paper presents a new induction approach called CRIS. The key notion employed in CRIS is that nominal and nonnominal attributes have different characteristics and hence should be analyzed differently. In the beginning of the paper, the benefits of this approach are described. Next, the basic elements of the CRIS approach are discussed and illustrated. This is followed by a series of empirical comparisons of the predictive validity of CRIS versus two entropy-based induction methods (ACLS and PLS1), statistical discriminant analysis, and the backpropagation method in neural networks. These comparisons all indicate that CRIS has higher predictive validity. The implications of the findings for expert systems design are discussed in the conclusion of the paper.