bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation-Based Estimation of Proportions
Authors: Raatikainen Kimmo E. E. 
Published: November 2008

Simulated estimates for several proportions are needed in many simulation studies. We propose a method for controlling the length of a simulation run so that the proportions estimated satisfy a prespecified precision requirement. The method applies the arcsin transform in order to generate confidence intervals with the desired width. The Bonferroni inequality is applied in a new way to construct a rectangular confidence area for the proportions being estimated. Since we are using the Bonferroni inequality, we can use the existing methods developed for estimating the variance of a single mean. The properties of the method proposed depend on three factors: 1) the arcsin transform, 2) the proposed way of applying the Bonferroni inequality, and 3) the method for estimating the variance. We examine the effects that the transform and the way of applying the Bonferroni inequality have. Empirical results indicate that the method provides estimates that satisfy the prespecified precision requirement, when the spectral method is used to estimate the variances of the proportions. In addition, simulation runs, when estimating either several proportions or the corresponding mean, are about the same lengths.
Verification of Uncertain Knowledge-Based Systems: An Empirical Verification Approach
Authors: O'Leary Daniel E. 
Published: November 2008

A number of different tests and approaches are developed to determine the existence of potential anomalies in rule-based systems that employ MYCIN uncertainty factors (weights). First, the distribution of weights is compared to other systems' distributions and weights are investigated as to their individual meanings, to determine whether any weights are unusual. Second, there is increasing evidence that people are not “good” at developing weights on rules, building in symmetries and redundancies that signal “usual” assumptions about the underlying probabilities. Accordingly, weight symmetries generated from rule pairs are analyzed to determine the existence of anomalies. Third, typically rule-based tools have been developed for application in specific domains, such as medicine. Unique aspects of those domains may limit application of the tools to other domains. Finally, ad hoc, rule-based approaches are suboptimal, and alternative formal probability approaches, such as Bayes' nets, more fully specify the probabilistic nature of knowledge. The paper is part of the empirical verification literature, where verification is done on an actual system and the system provides data that indicates the kinds of anomalies that can be expected. A case study is used to illustrate each of the verification tests and concerns.
Initial Data Truncation for Univariate Output of Discrete-Event Simulations Using the Kalman Filter
Authors: Gallagher Mark A. , Bauer Kenneth W. , Maybeck Peter S. 
Published: November 2008

Data truncation is a commonly accepted method of dealing with initialization bias in discrete-event simulation. An algorithm for determining the appropriate initial-data truncation point for univariate output is proposed. The technique entails averaging across independent replications and estimating a steady-state output model in a state-space framework. A Bayesian technique called Multiple Model Adaptive Estimation (MMAE) is applied to compute a time varying estimate of the output's steady-state mean. This MMAE implementation features the use, in parallel, of a bank of three Kalman filters. Each filter is constructed under a different assumption about the output's steady-state mean. One of the filters assumes that the steady-state mean is accurately reflected by an estimate, called the “assumed steady-state mean,” taken from the last half of the simulation data. This filter is called the reference filter. The remaining filters are calibrated with steady-state means corresponding to simple functions of the minimum and maximum data values, respectively. As the filters process the output through the effective transient, the reference filter becomes more likely (in a Bayesian sense) to be the best filter to represent the data, and the MMAE mean estimator is influenced increasingly towards the assumed steady-state mean. The estimated truncation point is selected when the MMAE mean estimate is within a small tolerance of the assumed steady-state mean. A Monte Carlo analysis using data generated from twelve simulation models is used to evaluate the technique. The evaluation criteria include the ability to estimate accurately and to construct reliable confidence intervals for the mean of the response based on the truncated sequences.
Budgets as Dynamic Gatekeepers
Authors: Pollack Harold , Zeckhauser Richard 
Published: November 2008

Most large organizations allocate resources by means of fixed budgets: each subunit is normally entitled to spend a defined amount over a fixed period, usually one year. Fixed budgets create clear incentives for subunits to control costs. Yet such arrangements create major incentives for dynamic inefficiency, for example by encouraging subunits to exhaust their budgets toward the end of the fiscal year. This paper develops a dynamic optimization model to examine the incentives fostered by budget systems. It invokes the metaphor of physicians involved in a health care delivery system to examine incentives created by decentralized “gatekeeping” as a mechanism to control medical costs. The paper also discusses some methods to reduce the incentives for dynamic inefficiency that fixed budgets create.
A Reference Lottery Metric for Valuing Health
Authors: Magat Wesley A. , Viscusi W. Kip , Huber Joel 
Published: November 2008

This study utilizes reference lotteries on life and death to establish a death-equivalent metric for valuing long-term health effects. We use a computer-based survey approach to elicit choices among residential locations that pose different risks of chronic disease and dying in an automobile accident. From paired choices between different locations, we infer their rates of trade-off between reducing the risks of chronic diseases and the automobile death risk. The values of reducing the risks from two diseases, a nerve disease (peripheral neuropathy) and lymphoma (cancer of the lymph system), are measured in terms of both trade-off rates with the risk of an automobile death and with dollars. While the use of reference lotteries for monetary outcomes to establish a utility metric is well established for monetary outcomes, our results suggest that reference lotteries on life and death can also be applied with decision-makers facing realistic choices to construct a utility metric for valuing health status. The results were corroborated by a strong positive correlation between the risk-risk trade-off values and relative aversion scores for the different health outcomes, as well as by the relative values of avoiding the three diseases in our study.
Mailing Decisions in the Catalog Sales Industry
Authors: Bitran Gabriel R. , Mondschein Susana V. 
Published: November 2008

Catalog sales are among the fastest growing businesses in the U.S. The most important asset a company in this industry has is its list of customers, called the house list. Building a house list is expensive, since the response rate of names from rental lists is low. Cash management therefore plays a central role in this capital intensive business. This paper studies optimal mailing policies in the catalog sales industry when there is limited access to capital. We consider a stochastic environment given by the random responses of customers and a dynamic evolution of the house list. Given the size of real problems, it is impossible to compute the optimal solutions. We therefore develop a heuristic based on the optimal solutions of simplified versions of the problem. The performance of this heuristic is evaluated by comparing its outcome with an upper bound derived for the original problem. Computational experiments show that it behaves satisfactorily. The methodology presented permits the evaluation of potential catalog ventures thus proving useful to entrepreneurs in this industry.
The Substitution of Information Technology for Other Factors of Production: A Firm Level Analysis
Authors: Dewan Sanjeev , Min Chung-ki 
Published: November 2008

Fueled by its constant technological and price improvements, information technology (IT) is displacing other inputs in the production of goods and services. By 1994, IT accounts for over 15% of fixed investments by the U.S. private sector, and the ratio of new IT investments to labor costs is approaching 5% (1990 dollar basis). The ability to take advantage of improvements in IT is determined in part by the substitutability of IT for other factors of production. This paper builds on the empirical framework of Brynjolfsson and Hitt (Brynjolfsson, E., L. Hitt. 1995. Information technology as a factor of production the role of differences among firms. Econom. Innovations and New Tech. 3 183–199.) and extends it to jointly estimate output and substitution elasticities using the CES-translog production function. Our primary source of IT-related data is the IDG/Computerworld annual survey data on IS spending by large U.S. firms, for the period 1988 to 1992, previously analyzed by Brynjolfsson and Hitt ([Brynjolfsson, E., L. Hitt. 1995. Information technology as a factor of production the role of differences among firms. Econom. Innovations and New Tech. 3 183–199.], [Brynjolfsson, E., L. Hitt. 1996. Paradox lost? Firm-level evidence on the returns to information systems spending. Management Sci. 42(4) 541–558.]) and Lichtenberg (Lichtenberg, F. R. 1995. The output contributions of computer equipment and personnel a firm level analysis. Econom. Innovations and New Tech. 3 201–217.). A key result is that IT capital is a net substitute for both ordinary capital and labor, suggesting that the factor share of IT in production will grow to more significant levels over time. We confirm earlier findings of positive returns to IT investment for this data set. Further, we find excess returns on IT investment relative to labor input and some evidence of excess returns relative to ordinary capital. Taken together, these results shed new light on the productivity paradox of IT and on the growth of information intensity across the economy as firms take advantage of the continuing improvements in IT.
Time Versus Market Orientation in Product Concept Development: Empirically-Based Theory Generation
Authors: Burchill Gary , Fine Charles H. 
Published: November 2008

In collaboration with industry partners, a normative model of the product concept decision process was developed, supported with tools and techniques, and codified as a decision support process for product development teams. This process (Concept Engineering) was then introduced into a number of product development teams in different companies. A comparative analysis of actual product concept development activities, with and without the use of Concept Engineering, was conducted. All of the observed teams viewed time to market as a critical measure of their success. However, the development processes differed significantly depending on whether relatively more emphasis was placed on time or market considerations. Key variables associated with the product concept development decision process and time-to-market dynamics were identified and a theory of the concept development process was developed using the inductive system diagram technique, a research methodology developed in the course of this work. We believe this work contributes to the operations management literature in three ways. First, it introduces a very detailed, structured decision process for product concept development, enhancing the literature on Quality Function Deployment (QFD). Second, it presents a theory of product concept development that can improve understanding of success and failure in product concept development. Third, this work develops new methodology (Inductive Systems Diagrams) for field work in operations management. This methodology marries the grounded theory methods familiar to sociologists with causal-loop modeling familiar to systems dynamicists, yielding a rigorous tool for systematically collecting, organizing, and distilling large amounts of field-based data.
Probabilistic Analysis of a Combined Aggregation and Math Programming Heuristic for a General Class of Vehicle Routing and Scheduling Problems
Authors: Federgruen Awi , van Ryzin Garrett 
Published: November 2008

We propose and analyze a heuristic that uses region partitioning and an aggregation scheme for customer attributes (load size, time windows, etc.) to create a finite number of customer types. A math program is solved based on these aggregated customer types to generate a feasible solution to the original problem. The problem class we address is quite general and defined by a number of general consistency properties. Problems in this class include VRPs with general distance norms, capacitated problems, time window VRPs, pick-up and delivery problems, combined inventory control and routing problems and arc routing. We provide a probabilistic analysis of this heuristic under very general probabilistic assumptions. In particular, we do not require independence between customer locations and their various attributes. The heuristic is (a.s.) ϵ-optimal as the number of customers n tends to infinity. Further, it runs in O(n log n) time for a fixed relative error, and can be designed to be asymptotically optimal while still running in polynomial time. We characterize the asymptotic average value of the heuristic and the optimal solution as the limit of a sequence of linear program values. We also provide bounds on the rate of convergence to the asymptotic value and bounds on tail probabilities. Finally, we discuss numerical issues involved in implementing our heuristic.
Cross-Disciplinary Evidence for Hyperbolic Social Discount Rates
Authors: Henderson Norman , Langford Ian 
Published: November 2008

Researchers in different disciplines have independently found evidence to suggest that the social discount rate may be hyperbolic, rather than exponential, in nature. Both behaviorist research and some empirical economics studies support the hyperbolic discounting hypothesis. U.S. and U.K. government discounting dispensations for some long-run public development projects are explicable in terms of an underlying hyperbolic social discount rate. A statistical aggregation argument demonstrates that even if the behaviorist, economics and public choice evidence for hyperbolic discounting is not conclusive, the social discount rate of a set of people who individually express time preferences best modeled by exponential discounting functions is nonetheless hyperbolic.Further empirical economics studies of discounting preferences are required. Comparisons of different national discounting practices would also be useful to see how widespread is the use of unusually low exponential rates of discount for long-run projects. The application of hyperbolic discounting would have most impact in long-run benefit-cost analyses. However, government agencies would require overwhelming evidence before switching from exponential to hyperbolic discounting.
Strategies for Survival in Fast-Changing Industries
Authors: Christensen Clayton M. , Suárez Fernando F. , Utterback James M. 
Published: November 2008

Technology strategy variables tend to predominate as predictors of survival in the fast-changing rigid disk drive industry. Building on these previous studies, we here test the hypothesis that the technological and market strategies of a new entrant are highly interrelated and that their joint effect plays an important role in a firm's probability of survival. In particular, we propose that firms that target new market segments with an architectural innovation will tend to be more successful than those that target existing markets or innovate in component technology, even after controlling for all the competing predictors of survival. This paper advances the existing literature on innovation by tracing the main technical elements of a dominant design in the rigid disk drive industry over time, and provides a much more rigorous definition of the concept of a dominant design than we have had in the past. We find the notion of first-mover advantage is not applicable in the rigid disk drive industry. Instead, we propose the idea of an entry-window tightly linked to the emergence of the dominant product design as defined.
Modeling Information Manufacturing Systems to Determine Information Product Quality
Authors: Ballou Donald , Wang Richard , Pazer Harold , Tayi Giri Kumar 
Published: November 2008

Many of the concepts and procedures of product quality control can be applied to the problem of producing better quality information outputs. From this perspective, information outputs can be viewed as information products, and many information systems can be modeled as information manufacturing systems. The use of information products is becoming increasingly prevalent both within and across organizational boundaries. This paper presents a set of ideas, concepts, models, and procedures appropriate to information manufacturing systems that can be used to determine the quality of information products delivered, or transferred, to information customers. These systems produce information products on a regular or as-requested basis. The model systematically tracks relevant attributes of the information product such as timeliness, accuracy and cost. This is facilitated through an information manufacturing analysis matrix that relates data units and various system components. Measures of these attributes can then be used to analyze potential improvements to the information manufacturing system under consideration. An illustrative example is given to demonstrate the various features of the information manufacturing system and show how it can be used to analyze and improve the system. Following that is an actual application, which, although not as involved as the illustrative example, does demonstrate the applicability of the model and its associated concepts and procedures.
Finding Optimal Material Release Times Using Simulation-Based Optimization
Authors: Homem-de-Mello Tito , Shapiro Alexander , Spearman Mark L. 
Published: November 2008

We present a method for setting release times for jobs with due dates in a stochastic production flow line for which the sequence of jobs has been determined. Unlike other approaches to this problem, ours considers a transient situation. Thus, the flow line will typically contain work in process (WIP), that is, jobs that have been previously released to the system. Our goal is to develop a job release schedule that not only minimizes tardiness but also maximizes flexibility. The philosophy can be characterized as one that seeks to “release as late as possible, but no later!” Our methodology is based on Monte Carlo simulation and consequent optimization by a method that became known as “stochastic counterpart” or “sample path” simulation-based optimization techniques. We use this method to minimize an expected value objective function that contains terms for tardiness and flow time “costs.” We include a discussion of how the cost parameters of this objective function can be obtained by considering a “characteristic curve” for the system. We also discuss means for obtaining sensitivity analysis with respect to due dates and service times distributions parameters. We conclude with a numerical example.
Project Scheduling Under Partially Renewable Resource Constraints
Authors: Böttcher Jan , Drexl Andreas , Kolisch Rainer , Salewski Frank 
Published: November 2008

We consider a generalization of the classical resource constrained project scheduling problem. We introduce so-called partially renewable resources by assuming for each resource a capacity on subsets of periods. The concept of partially renewable resources is a fundamental tool in order to make, e.g., timetabling and shift scheduling aspects, amenable to project scheduling. In addition, partially renewable resources serve to model complicated labor regulations. Furthermore, they cover traditional renewable and nonrenewable resource constraints as special cases. We consider makespan minimization as objective. For the exact solution of the problem we employ a basic enumeration scheme. In order to speed up convergence, we formulate bounds which take into account future resource consumption of partially renewable resources. Moreover, we generalize the serial scheduling scheme in order to get fast approximation methods. A rigorous assessment of the procedures is provided by solving ProGen instances generated under a full factorial test design. Besides the well-known problem parameters we employ additionally three parameters which control the generation of partially renewable resources.
The Effects of Human Resource Management Systems on Economic Performance: An International Comparison of U.S. and Japanese Plants
Authors: Ichniowski Casey , Shaw Kathryn 
Published: November 2008

This study uses personally collected data from 41 steel production lines to assess the effects of Japanese and U.S. human resource management (HRM) practices on worker productivity. The Japanese production lines employ a common system of HRM practices including: problem-solving teams, extensive orientation, training throughout employees' careers, extensive information sharing, rotation across jobs, employment security, and profit sharing. A majority of U.S. plants now have one or two features of this system of HRM practices, but only a minority have a comprehensive system of innovative work practices that parallels the full system of practices found among the Japanese manufacturers.We find that the Japanese lines are significantly more productive than the U.S. lines. However, U.S. manufacturers that have adopted a full system of innovative HRM practices patterned after the Japanese system achieve levels of productivity and quality equal to the performance of the Japanese manufacturers. This study's evidence helps reconcile conflicting views about the effectiveness of adopting Japanese-style worker involvement schemes in the United States. United States manufacturers that have adopted a definition of employee participation that extends only to problem-solving teams or information sharing do not see large improvements in productivity. However, U.S. manufacturers that adopt a broader definition of participation that mimics the full Japanese HRM system see substantial performance gains.
What Price Fairness? A Bargaining Study
Authors: Zwick Rami , Chen Xiao-Ping 
Published: November 2008

Our study concerns bargaining behavior in situations where one party is in a stronger position than the other. We investigate both the tradeoff the favored party makes between pursuing his strategic advantage and giving weight to other players' concern for fairness, and the tradeoff the disadvantaged player makes between pursuing a fair outcome from a disadvantaged position and the cost of that pursuit. In particular, we hypothesize that the degree to which strategically strong players attempt to exploit their strategic advantage depends on their potential costs for doing so. Similarly, the degree to which weak players persist in seeking “fairness” is also a function of how much it (potentially) costs them to do so.Students negotiated in pairs over the division of $HK50 using a finite horizon, fixed-cost (per rejection) alternating offer rule. Each pair consisted of a high-cost and a low-cost bargainer. In accordance with the hypothesis, the willingness of the high-cost bargainers to demand fairness and to persist in their demands was a function of how much it cost them to do so, and the degree to which the low-cost bargainers attempted to exploit their strategic advantage depended on their own cost of rejection. We conclude that “fairness” has a price such that the higher its price, the lower the “demand” for it. This suggests that demands for fairness are subject to cost-benefit evaluation, are in this sense deliberate, and are well thought out.