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An Update on a Successful Simulation Project: The UNOS
Liver Allocation Model
Ann M. Harper, Sarah E. Taranto, Erick B.
Edwards, and O. Patrick Daily (United Network for Organ Sharing)
Abstract:
The UNOS Liver Allocation Model (ULAM) is a simulation
of the cadaveric liver allocation system in the United States. ULAM was
created by the United Network for Organ Sharing (UNOS) in collaboration with
Pritsker Corporation/Symix Systems, to permit comparison of multiple liver
allocation policy proposals so that policies can be tested prior to
implementation. ULAM is extremely adaptable, and with it UNOS has been able to
respond to varied and complex requests for policy analysis. ULAM has aided
UNOS throughout the highly publicized national liver allocation debate, and
its use is anticipated for the foreseeable future. The authors believe that
ULAM is an excellent example of simulation technology used to resolve national
medical policy issues. The success of ULAM, in terms of its ease of use,
flexibility of design, and acceptance by the transplant community, has
reinforced UNOS' desire to create other organ allocation models. This paper
provides a brief description of ULAM's structure, and summarizes the evolution
of ULAM from 1995 to 2000.
Using Simulation for the Economic Evaluation of Liver
Transplantation
Lynne P. Baldwin, Tillal Eldabi, and Ray J. Paul
(Brunel University) and Andrew K. Burroughs (Royal Free Hospital)
Abstract:
This paper demonstrates the use of simulation in an
evaluative study for the technology of liver transplantation from
cost-effectiveness point of view. This study is conducted in the United
Kingdom where there are no explicit guidelines for the prioritization of
patients waiting for transplantation. Another objective of the model is to
enable health economists to understand the technology of liver transplantation
and evaluate alternative policies for prioritizing patients in the waiting
list. The paper shows the construction of a tailor-made package (LiverSim) and
provides an example of how this package is used by the stakeholders to assist
in the evaluation process. Some final lessons are drawn that simulation helps
in exploring more issues outside the boundaries of quantitative results.
Developing a National Allocation Model for Cadaveric
Kidneys
Sarah E. Taranto, Ann M. Harper, Erick B. Edwards, John D.
Rosendale, Maureen A. McBride, and O. Patrick Daily (United Network for Organ
Sharing), Dan Murphy, Bill Poos, and Janet Reust (Symix Systems) and Bruce
Schmeiser (Purdue University)
Abstract:
The UNOS Kidney Allocation Model (UKAM) is a software
tool for the simulation and analysis of national cadaveric kidney and
kidney-pancreas allocation policies for transplantation. UKAM is modular and
is designed to enable easy updating of the various components as new data
become available. UKAM’s flexibility gives the user the ability to create and
evaluate an almost infinite number of detailed allocation policies. This will
enable the United Network for Organ Sharing (UNOS) to make decisions based on
quantitative data when considering changes in organ allocation policies.
A Simulation Study of the Radiology Department at
JMH
Martha A. Centeno (Florida International University), Cristina
Albacete (Florida Power and Light), Diego O. Terzano (Florida International
University) and Manuel Carrillo and Tom Ogazon (Jackson Memorial Hospital)
Abstract:
This paper discusses a study of the Radiology
department at Jackson Memorial Hospital. The animated simulation model was fed
data from the operations database. Several inefficiencies were identified, and
suggestions for improvement were explored. These adjustments included six
scenarios: 1) Current system, 2) Modeling each procedure to take place with
the assistance of only one technologist, 3) Modeling each procedure to take
place with the assistance of two technologists, 4) Addition of a new
Neurological operating room, 5) Addition of a designated pre-holding area for
the patients' comfort, and 6) One-day extension in the weekly operating
schedule. It was identified that under scenario 2 (one technologist) the total
time in the system was significantly lower than the current system and
scenario 3 (two technologists). However, this scenario also gave the lowest
utilization rate for the eight technologists and the lowest utilization rate
for the operating rooms. To increase efficiency, other recommendations were
made.
Monte Carlo Simulation Experiments for Analysis
of HIV Vaccine Effects and Vaccine Trial Design
Daniel C.
Barth-Jones (Wayne State University), Andrew L. Adams (NextHop Technologies)
and James S. Koopman (University of Michigan)
Abstract:
The field of infectious disease epidemiology has
increasingly adopted stochastic simulation technologies to simulate complex
infectious disease transmission systems. Such simulations have both increased
the scientific understanding of infectious disease transmission dynamics and
served as important tools for evaluating epidemiologic study designs and
statistical methods. This paper reports on a discrete-event simulation to
analyze the recently developed Retrospective Partner Trials (RPT) HIV vaccine
trial design. A specially designed simulation system, HIVSIM, was used to
simulate data resulting from the RPT design vaccine trials. HIVSIM explicitly
models complex HIV transmission dynamics (e.g., sexual partner mixing patterns
and concurrent sexual partnerships) and vaccine trial design characteristics.
Monte Carlo simulation analyses conducted with HIVSIM indicate that the RPT
design is able to produce vaccine effect estimates with acceptably small bias,
high precision and excellent statistical power under plausible HIV vaccine
trial conditions. Additionally, the explicit simulation of HIV transmission
dynamics permits investigations into the common, but unwarranted, statistical
independence assumptions routinely used in the estimation of vaccine effects.
Simulation of the Drug Development Process: A Case
Study from the Pharmaceutical Industry
Russell W. Workman (Andersen
Consulting)
Abstract:
This paper uses a case study from the pharmaceutical
industry to show how simulation modeling can be applied to understanding
large, highly-complex processes such as drug development. I conclude that
simulation provides an enhanced resource planning capability compared with
that provided by traditional spreadsheet analysis. This capability difference
stems from the ability of a simulation to better reflect the variation which
defines such complicated processes. The conditions which facilitate
exploitation of this advantage include: capturing process information at the
correct level of abstraction; successfully incorporating this information into
a simulation model; and allowing easy user access to critical parameters via
an intuitive interface.
Emerging Issues in Healthcare
Simulation
Susan M. Sanchez (Naval Postgraduate School), David M.
Ferrin (Andersen Consulting), Tom Ogazon (Jackson Memorial Hospital), José A.
Sepúlveda (University of Central Florida) and Timothy J. Ward (Health Services
Engineering)
Abstract:
Despite the size and importance of the health care
industry, simulation is less prevalent in health care than in other fields
such as manufacturing, logistics, and military applications. Yet simulation
clearly has the potential to play a role in health care decision-making at
many levels. The purpose of this panel is to discuss some of the issues that
practioners must be aware of in order to tap the potential of simulation in
the health care arena. The panelists have extensive experience in health care
and the use of simulation in that environment. They have provided statements
outlining several key issues for achieving success in current and future
health care simulation projects. These will serve as the starting point for
discussion at the conference.
Effective Uses of Business Process
Simulation
Andrew Greasley (University of Derby)
Abstract:
This paper evaluates a number of tools for the redesign
of processes through the use of two case studies based in the UK Police
Service. There is a particular emphasis on the use of Business Process
Simulation in conjunction with Activity Based Costing and Activity Based
Budgeting within the context of a Business Process Reengineering approach. The
use of a balanced scorecard and marking guide can be used to identify suitable
processes for redesign. A process map enables a study of the relationship
between the activities that form the process. The process map relates to the
conceptual map in a simulation study. A Business Process Simulation based on
the logic contained in a process map is demonstrated to enable a dynamic
analysis of current process performance and proposed process design. To ensure
that the results of the study are implemented the balanced scorecard can be
used to set operational targets for performance measures. The current
political and cultural context of the organisation should also be taken into
account to ensure successful implementation.
Enterprise Simulation: Framework for a Strategic
Application
Milind M. Datar (Concert, an AT&T and BT Global
Venture)
Abstract:
The term Enterprise Simulation (ES) is gaining
acceptance among simulation practitioners. It is coming to represent certain
tangible attributes, and its benefits seem apparent in providing a top-down
perspective in system analysis. It is envisioned as the next wave of
simulation applications that may bring simulation to a higher ground of
applicability in the business application arena. ES does so by promising to
extend the benefits of simulation modeling and analysis as it is performed
today. Linking singular instances of analytical efforts (simulation and
otherwise) with limited scope in a network has the potential of delivering
extraordinary value to decision-making at the corporate level. Moreover,
advances in distributed simulation concepts and networking technology can
provide the much needed push to ES by serving as enablers. This paper offers
to explain the motivation behind ES, and explain its relevance to the business
environment of large, complex organizations. A development framework is
presented with technical and managerial issues in its implementation.
Applications of Business Process Simulation and Lean
Techniques in British Telecommunications PLC
Simon Dennis, Ben
King, and Martin Hind (British Telecommunications PLC) and Stewart Robinson
(The University of Warwick)
Abstract:
Business processes are increasingly key to the success
of companies in the service industry. It is important that these processes are
designed and maintained to deliver the most cost effective and efficient
results. Simulation is being used in conjunction with other techniques to
improve the performance of BT's processes, to evaluate new ideas and to plan
operational resource requirements. The examples in this paper discuss firstly,
the use of Value Stream Analysis (VSA) to identify inefficiencies in business
processes and how simulation is used to evaluate improvement plans/develop
future business scenarios derived from this, and secondly how simulation is
used to match available resources to workloads.
Simulation Modelling: The Link between Change
Management Panaceas
Wendy Currie and Vlatka Hlupic (Brunel
University)
Abstract:
Although change management panaceas have been widely
discussed in the business and management literature for several decades, not
many publications address the role of simulation modeling in supporting these
panaceas. This paper investigates four management innovation and change
programs: TQM, JIT, BPR and Process Innovation and discusses how simulation
modeling could increase their effectiveness. These change management
approaches are compared and contrasted and the applicability of simulation
modeling to support the principles of these methods is investigated. It is
argued that simulation could be viewed as a missing link between these
approaches.
Creating a Paperless Municipal Court
John
M. Petrakis (BIRG, Inc.) and Michael J. Engiles (CACI, Inc)
Abstract:
SIMPROCESSÒ was used to plan a phased migration from a
traditional municipal court to a paperless court. The simulation model was
also used to provide the financial justification, communication of the
concept, and plan staffing for the revised operational procedures.
Venture Launch: Use of Simulation to Support Strategic
Operational Decisions
Gregory R. Clay (Andersen Consulting)
Abstract:
This paper describes how discrete-event simulation
enhanced a traditional process design effort for a new media company in
pre-launch mode. Because the company’s business model is new, and thus its
critical operational processes are new, a need existed to not only design the
new processes but also to determine at a high level the “goodness” of the
proposed design. This high-level approach to simulation modeling can open new
doors to simulation professionals accustomed to performing detailed simulation
analyses. Benefits derived from use of the high-level simulation along with
considerations for using high-level models in this rapidly changing
environment are discussed.
Using Information Generated by the Discrete Event
Simulation to Evaluate Real Options in a Research and Development
Environment
Jerry Flatto and L. Leslie Gardner (University of
Indianapolis)
Abstract:
This article examines how a discrete event simulation
can be developed to evaluate the impact of real options on a research and
development project. Previous work with real options has been primarily
mathematically based and the approach was not transferable to actual projects.
The results shown in this article indicate that simulation is a valid method
to evaluate real options and that the real options do impact the net present
value of a process.
The Merger of Discrete Event Simulation with Activity
Based Costing for Cost Estimation in Manufacturing
Environments
Ulrich von Beck and John W. Nowak (University of
Illinois at Urbana-Champaign)
Abstract:
Activity based costing (ABC) has revolutionized product
costing, planning, and forecasting in the last decade. It is based on a
philosophy of estimation that: "it is better to be approximately right, than
precisely wrong." The philosophy of discrete-event simulation modeling follows
a similar tack, where statistical inference and the stochastic nature of
processes are used to replicate the behavior of a physical system. In this
work, ABC and discrete-event simulation are linked to provide an improved
costing, planning, and forecasting tool. Numerous point cost estimates are
generated by the ABC model, using driver values obtained from a discrete-event
simulation of the process. The various cost estimates can be used to produce
confidence interval estimates of both the physical system and underlying cost
structure. Rather than having a single point estimate of a product's cost, it
is now possible to produce the range of costs to be expected as process
conditions vary. This improved cost estimate will support more informed
operational and strategic decisions.
Electronic Workflow for Transaction-Based Work Cells
in a Financial Services Firm
David M. Ferrin, Martin J. Miller, and
Gustavo Giron (Andersen Consulting)
Abstract:
In determining an electronic documentation system, a
financial services firm utilized simulation to determine the necessary capital
expenditure. Analysis included batching options, Service Level Agreements and
Full Time Equivalent allocations and schedules. This information was then
processed in transaction-based work cells which were redesigned using
simulation. This paper discusses approach, benefits and lessons learned while
developing multiple simulation models for an electronic documentation system.