Preston White

Preston White
University of Virginia | UVa · systems and information

PhD

About

125
Publications
41,408
Reads
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2,004
Citations
Citations since 2016
18 Research Items
467 Citations
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080

Publications

Publications (125)
Conference Paper
Full-text available
It is common to find a mixture of both long batch jobs and latency-sensitive short jobs in enterprise data centers. Recently hybrid job schedulers emerge as attractive alternatives of conventional centralized job schedulers. In this paper, we conduct trace-driven experiments to study the job-completion-delay performance of two representative hybrid...
Article
Full-text available
The original version of this article unfortunately contained a mistake. The name of Matthew Gerber was incorrectly spelled as Mathew Gerber. The correct spelling is now presented correctly in this correction article.
Article
Full-text available
The Veterans Health Administration (VHA) is plagued by abnormally high no-show and cancellation rates that reduce the productivity and efficiency of its medical outpatient clinics. We address this issue by developing a dynamic scheduling system that utilizes mobile computing via geo-location data to estimate the likelihood of a patient arriving on...
Conference Paper
The incarceration of mentally ill individuals in the Unites States has come under increased scrutiny in recent years due to both ethical and practical concerns. This paper describes research aimed at advancing the understanding of the treatment of the mentally ill population within the local criminal justice system. Specifically, it (1) demonstrate...
Conference Paper
The Orthopaedic and Sports Medicine Clinics of the University of Virginia Health System are collocated in the Fontaine Research Park. The two departments operate in separate clinics, but share a Radiology Department. Collectively, the clinics serve about 42,000 outpatient visits annually. With patient visits projected to increase substantially in t...
Conference Paper
One of the most pressing issues facing the American healthcare system is an inability to meet the ever-increasing demand for emergency department (ED) care. EDs across the country are experiencing overcrowding that exhausts resources, creates unacceptable waiting times, diminishes the quality of patient care, and increases financial costs for both...
Conference Paper
Full-text available
Simulation is experimentation with a model. The behavior of the model imitates some salientaspect of the behavior of the system under study and the user experimentswiththe model to infer this behavior. This general framework has proven a powerful adjunct tolearning,problem solving,design, and control. In this tutorial, we focus principally on discr...
Conference Paper
The focus of this project is to facilitate program evaluation by creating a database that captures data about incidents, offenders, and offenses across the entire criminal justice system, while complying with national justice information sharing standards and maintaining individual stakeholders' legacy data systems. Current systems support individu...
Conference Paper
Full-text available
We all know how to estimate a confidence interval for the mean based on a random sample. The interval is centered on the sample mean, with the half-width proportional to the sample standard error. We know also that terminating simulations generate independent observations. What simulators appear to have overlooked is that independence alone is insu...
Article
Early in a program, engineers must determine requirements for system reliability and availability. We suggest that existing techniques gathered from diverse fields can be incorporated within the framework of systems engineering methodology to accomplish this. Specifically, adopting probabilistic (Monte Carlo) design techniques allows the designer t...
Conference Paper
At the University of Virginia (UVa) Hospital, medical residents and interns serve month-long rotations through different medical specialties. The competing considerations governing the annual assignment and scheduling of rotations are complex, including hospital staffing requirements, individual preferences for specialties and holidays, breadth of...
Conference Paper
Full-text available
The criminal justice system in the greater Albemarle-Charlottesville area faces a number of challenges common to many communities, including frequent overcrowding at the regional jail and data systems that obstruct analysis needed to identify causes of and remedies for overcrowding. The Community Criminal Justice Board (CCJB) would like to make evi...
Conference Paper
Full-text available
This paper addresses the construction of a consistent interval estimator for the steady-state mean within a replication/deletion framework for output analysis when MSER truncation is applied. Because the MSER truncation point is a random variable, the truncated output sequences for each replication typically are unequal in length. A weighting schem...
Article
The Albemarle-Charlottesville Regional Jail, having been built to house less than the forecasted inmate population, is currently operating at 150% of its rated capacity. The ever growing inmate population has put a strain on the already limited jail resources. As the jail becomes more crowded, it is even more difficult to rehabilitate inmates. Cons...
Chapter
This article describes the problem of the initial transient that arises when estimating the limiting distribution of a nonterminating stochastic process. Concepts are explored with references to simple M/M/1 queueing model with an artificially induced initial bias. A range of solution methods have been proposed and here we explore two such approach...
Conference Paper
The Albemarle-Charlottesville Regional Jail, having been built to house less than the forecasted inmate population, is currently operating at 150% of its rated capacity. The ever growing inmate population has put a strain on the already limited jail resources. As the jail becomes more crowded, it is even more difficult to rehabilitate inmates. Cons...
Article
Full-text available
In a comprehensive study of methods for mitigating the problem of the initial transient, Hoad et al (2009) conclude that MSER (White, 1997) is an efficient, effective, and robust truncation rule, appropriate for automation. Franklin and White (2008) suggest that MSER works because it minimizes an approximation to the mean-squared error in the estim...
Conference Paper
Full-text available
The MSER algorithm for determining the warm-up period in steady-state simulations was introduced in 1990. Over the past two decades, empirical evaluations by different research teams have demonstrated the effectiveness of the procedure. These extensive empirical results illustrate the relative advantage of MSER over other approaches under alternati...
Article
One out of every 100 Americans is incarcerated, many for drug-related offenses [1]. The resulting strain on correctional facilities nationwide has prompted recent research on the effectiveness of substance abuse treatment during incarceration. The LOCUST Therapeutic Community (TC) at the Albemarle-Charlottesville Regional Jail in Charlottesville, V...
Conference Paper
Full-text available
Simulation is experimentation with a model. The behavior of the model imitates some salient aspect of the behavior of the system under study and the user experiments with the model to infer this behavior. This general framework has proven a powerful adjunct to learning, problem solving, and design. In this tutorial, we focus principally on discrete...
Article
Yield analysis is an important activity in the assessment and control of semiconductor fabrication processes. Tests of spatial randomness provide a means of enhancing yield analysis by considering the patterns of good and defective chips on the wafer. These patterns can be related to the likely sources of defects during production. This paper compa...
Article
Developed by quality engineers as an efficient statistical approach to verifying the acceptability of procured items within production environments, acceptance sampling can be generalized to other verification problems which similarly rely on the outcomes of stochastic sampling experiments. This article illustrates how the techniques and perspectiv...
Conference Paper
Full-text available
Probabilistic engineering design enhances safety and reduces costs by incorporating risk assessment directly into the design process. In this paper, we assess the format of the quantitative metrics for the vehicle which will replace the Space Shuttle, the Ares I rocket. Specifically, we address the metrics for in-flight measurement error in the vec...
Conference Paper
This paper summarizes a Capstone Project focused on evaluating the energy use of the John Paul Jones Arena (JPJ). JPJ is a multipurpose arena and uses a tremendous amount of energy each day. An energy analysis of the John Paul Jones Arena was conducted and primary categories of energy use were identified as: electricity, hot water, and chilled wate...
Conference Paper
Full-text available
Limit standards are probability interval requirements for proportions. Simulation literature has focused on finding the confidence interval of the population proportion, which is inappropriate for limit standards. Further, some Frequentist approaches cannot be utilized for highly reli- able models, or models which produce no or few non- conforming...
Conference Paper
Full-text available
We explore the reasoning behind MSER-5, an efficient and effective truncation heuristic for reducing initialization bias in steady-state simulation. We also compare MSER-5 with the KPSS stationarity test as one means of investigating the possibility that MSER¿s effectiveness is the result of its utility as a stationarity measure. Conversely, this...
Article
While advances in call-centre technologies offer increased capabilities and efficiencies, the expanded possibilities for alternative configurations and operating policies complicate call-centre design and management correspondingly. Discrete-event simulation can capture these complexities and assist call-centre management in leveraging new technolo...
Article
The Hough transformation employing a normal line-to-point parameterization is widely applied in digital image processing for feature detection. In this paper, we demonstrate how this same transformation can be adapted to classify defect signatures on semiconductor wafers as an aid to visual defect metrology. Given a rectilinear grid of die centers...
Conference Paper
Reflecting the national overcrowding crisis, the Albemarle-Charlottesville Regional Jail (ACRJ) in Charlottesville, Virginia, currently operates at 150 percent of its rated capacity. The jail must accommodate all offenders detained in the City of Charlottesville and the Counties of Albemarle and Nelson despite infrastructure and personnel limitatio...
Conference Paper
Limit standards are probabilistic requirements or benchmarks regarding the proportion of replications conforming or not conforming to a desired threshold. Sample proportions resulting from the analysis of replications are known to be beta distributed. As a result, standard constructs for defining a confidence interval on such a proportion, based on...
Conference Paper
Full-text available
Five text mining software tools were evaluated by four undergraduate students inexperienced in the text mining field. The software was run on the Microsoft Windows XP operating system, and employed a variety of techniques to mine unstructured text for information. The considerations used to evaluate the software included cost, ease of learning, fun...
Conference Paper
Full-text available
Limit standards are probabilistic requirements or benchmarks regarding the proportion of replications conforming or not conforming to a desired threshold. Sample proportions resulting from the analysis of replications are known to be beta distributed. As a result, standard constructs for defining a confidence interval on such a proportion, based on...
Conference Paper
We continue our research into the comparison, via simulation experiments, of a stochastic system to a limit standard. A limit standard is defined as a maximum and/or minimum standard. We have found that evaluation methods using proportions provide a statistically valid comparison of this family of standards. In this paper, we present the use of Wal...
Conference Paper
Full-text available
Simulation professionals understand the importance of accurate data for model validation. Traditional sources of simulation data come from information technology systems, manual records from staff, observations, and estimates by subject matter experts. This paper discusses how radio frequency identification (RFID) technologies were used on a recent...
Article
The authors describe the adaptation of a hierarchical management-control framework to the design of intelligent real-time scheduling systems. Originally developed for the analysis of organizations where dynamics are governed solely by the reactions of human decision makers, the control framework provides insights concerning design requirements for...
Article
The authors describe the adaptation of a hierarchical management-control framework to the design of intelligent real-time scheduling systems. Originally developed for the analysis of organizations where dynamics are governed solely by the reactions of human decision makers, the control framework provides insights concerning design requirements for...
Article
Full-text available
The goal of this project was to design a card game simulation of financial trade markets. In a trading environment, a market maker quotes two prices for a specific type of financial instrument, such as a stock option. Traders then buy shares from or sell shares to the market maker. The decision of the market maker to quote prices at certain levels,...
Chapter
The design of modern control systems relies on the formulation and analysis of mathematical models of dynamic physical systems. Physical systems are represented by connecting the terminals of pure elements in patterns that approximate the relationships among the properties of component devices. The element laws and system relations together constit...
Conference Paper
Full-text available
Modeling and simulation studies of patient flows in healthcare systems have been reported consistently in these proceedings for over a decade. Our ongoing research in this area is motivated by our desire to develop models which will illuminate the causes and remedies for repeated area-wide ambulance diversions experienced in a metropolitan hospital...
Conference Paper
Full-text available
This paper describes on-going research, where we compare, via simulation experiments, a stochastic system to a standard. We are particularly interested in a subset of standards we call limit standards. A limit standard is a maximum or minimum benchmark derived from requirements, another model, or the actual system. The problem is to determine if a...
Conference Paper
Full-text available
We continue our research into the comparison, via simulation experiments, of a stochastic system to a limit standard. A limit standard is defined as a maximum and/or minimum standard. We have found that evaluation methods using proportions provide a statistically valid comparison of this family of standards. In this paper, we present the use of Wal...
Conference Paper
Full-text available
Simulation professionals understand the importance of ac- curate data for model validation. Traditional sources of simulation data come from information technology sys- tems, manual records from staff, observations, and esti- mates by subject matter experts. This paper discusses how Radio Frequency Identifica- tion (RFID) technologies were used on...
Article
We discuss the practical, professional education in information systems and operations management available to undergraduate systems engineers at the University of Virginia through participation in relevant Capstone projects in this paper. Thus, its perspective is more experiential than theoretical. The structure and administration of the Departmen...
Article
We discuss the program-level model used in the administration of undergraduate Capstone (senior design) projects in the Department of Systems and Information Engineering at University of Virginia's School of Engineering and Applied Science in this paper. A unique model at the time of its inception in 1988, its adoption by other institutions and its...
Conference Paper
Full-text available
Aerojet is a leading manufacturer of propulsion systems for military and space applications. Like all technology companies, Aerojet faces the challenge of allocating limited research and development (R&D) funds among competing technology projects with uncertain rewards. This paper describes the design and implementation of improvements to an annual...
Conference Paper
Full-text available
This project simulates and analyzes the inspection process of cargo containers as they enter the United States seaports. The purpose for this project is to create a more efficient inspection process allowing more containers to be inspected without too significant of a cost. The inspection process that was simulated has four major parts. The differe...
Conference Paper
Full-text available
This paper explores an approach to global, stochastic, simulation optimization which combines stochastic approximation (SA) with simulated annealing (SAN). SA directs a search of the response surface efficiently, using a conservative number of simulation replications to approximate the local gradient of a probabilistic loss function. SAN adds a ran...
Conference Paper
Full-text available
Solid rocket propellants are critical components in weapons, automobile airbag, and satellite technologies. The instantaneous rate at which a propellant burns is an essential design parameter in all of these applications. While existing formulas accurately predict burn rates for most solid engine propellants, these standard equations assume that th...
Conference Paper
Full-text available
Solid rocket propellants have various applications, including weapons, satellites, and air bag technology. In these applications burn rate and pattern prediction are important parameters in predicting ballistic motor performances and motor design. While existing equations accurately predict burn rates for most solid engine propellants, these standa...
Conference Paper
Full-text available
Framatome ANP (FANP) recently merged with Siemens Power Corporation to form one of the world's largest suppliers of fuel assemblies for commercial nuclear power plants. This merger offers the potential for cost reductions and logistical improvements through the integration of FANP's two North American fuel fabrication facilities. According to plan,...
Conference Paper
Full-text available
AutoMod<sup>®</sup> is a leading discrete-event simulation package widely applied in the modeling and analysis of distribution systems. Included in the AutoMod software suite is the Model Communications Module (MCM), which allows an executing simulation to open socket connections and to send and receive messages via TCP/IP network protocol. In this...
Conference Paper
Full-text available
In semiconductor manufacturing, cracks, scratches, contaminants, process variations, and errors by operators or equipment are all production problems that cause defects on wafers. It is highly desirable to find and classify defect signatures recorded in the data sets for final electrical tests and to correlate these signatures with causal data resi...
Conference Paper
AutoMod® is a leading discrete-event simulation package widely applied in the modeling and analysis of distribution systems. Included in the AutoMod software suite is the Model Communications Module (MCM), which allows an executing simulation to open socket connections and to send and receive messages via TCP/IP network protocol. In this paper we r...
Conference Paper
Full-text available
Discrete-event simulation is an established tool for the design and management of large-scale mail sorting and distribution systems. Because the design of distribution facilities integrates many of the same or functionally similar components, adopting an object-oriented approach to simulation promises significant economies. Instead of coding and ve...
Article
Full-text available
We compare the performance of five well-known truncation heuristics for mitigating the effects of initialization bias in the output analysis of steady-state simulations. Two of these rules are variants of the MSER heuristic studied by White (1997); the remaining rules are adaptations of bias-detection tests based on the seminal work of Schruben (19...
Article
Modeling and simulation studies of patient flows in healthcare systems have been reported consistently in these Proceedings for over a decade. Our ongoing research in this area is motivated by our desire to develop models which will illuminate the causes and remedies for repeated areawide ambulance diversions experienced in a metropolitan hospital...
Article
A discrete-event simulation is developed that captures the processing of wafers through an advanced X-ray lithography area employing multiple synchrotrons as the source of exposure radiation. The model incorporates the best current information on unit cell design and processing. Detailed model logic implements a range of unscheduled events that rep...
Article
A companion paper describes a discrete-event simulation model that captures the processing of wafers through a next-generation X-ray lithography area employing multiple synchrotrons as the source of exposure radiation. The model incorporates the best current information on unit-cell design and processing times; implements the spectrum of events tha...