WSC 2006 Abstracts

Poster Session (A) Track

Monday 5:00:00 PM 6:30:00 PM
Poster Session A

Chair: Theresa Roeder (San Francisco State University)

Development of Criterion Models for Use in Simulation Analysis
Gerald W. Evans (University of Louisville) and Nicholas P. Anderson (Decisive Analytics Corporation)

Criterion models are important components in analyses of simulation output. These models represent the basis by which decision makers can rank alternatives in a simulation study. This work gives an overview of criterion models, especially as related to their uses with simulation models. In particular, examples of criterion models used in simulation studies are given. In addition, methodologies for choosing a set of attributes for a criterion model are described, along with a discussion of how these attributes should be “combined” in order to form a criterion model.

Finding Probably Best Systems Quickly Via Simulation
Takayuki Osogami (IBM Tokyo Research Laboratory)

The performance of computer systems can in theory be optimized by selecting the system configuration having the best simulated performance. Unfortunately, it is often computationally intractable to estimate the performance of all system configurations accurately via simulation. We propose an algorithm for finding the best system configuration without estimating the performance of each system configuration accurately, so that the total simulation time is minimized. We prove that with high probability our algorithm finds the best system configuration. In addition, our algorithm has an advantage in that it only infrequently changes the system configurations to be simulated. Numerical experiments show that our algorithm improves upon existing algorithms with respect to the total simulation time and the frequency of changing the system configurations.

Epidemics Alert & Response Framework and Technology based on Spreading Dynamics Simulation
Chunhua Tian, Xun Zhang, Wei Ding, and Rongzeng Cao (IBM China Research Lab)

There have been many research works on epidemic spreading using athematical or simulation methods. However, to make it practical as a decision support tool for the policy maker, it needs to be combined with business operation of epidemic control. Thus, an alert and response framework covering outbreak detection, policy analysis, and policy execution is proposed in this work. Key technologies for such a framework at the modeling, analysis, and data collection aspects are discussed. Sensitivity analysis is proposed for model verification and confidence analysis. Critical point identification is another important topic for control policy making by network topology analysis. The importance and feasibility of these technologies are illustrated by the experiment on Beijing SARS (Severe Acute Respiratory Syndrome) data in 2003.

Volume Fusion: A Unified Frame Work for Multi-Scale Dynamic and Heterogeneous Scenes
Duoduo Liao (George Washington University) and Shiaofen Fang (Indiana University/Purdue University Indianapolis)

This work presents a novel unified solution -- a volume fusion framework for 3D modeling, interaction, and visualization applications with complex volumetric scenes composed of any type of conventional and unconventional object representations. The process of volume fusion includes scene expression and scene evaluation. A volume scene evaluation based on slice sweeping approach is employed to provide a general computational framework that extracts volumetric information of the scene expression and then fuse them by specified fusion functions. The key issues of volume fusion are scene tree design and fusion function design. Through the unified framework, different tree structures and fusion functions may result in different outputs (i.e., applications) after scene evaluation. Two case studies, volume modeling and volumetric collision detection, using volume fusion framework will be discussed in detail, and the experimental results demonstrate the effectiveness, flexibility and generality of our volume fusion algorithms for 3D interactive volume applications.

Modeling of Individual Decision Making in Mass Customization Markets
Zbigniew J Pasek (University of Windsor)

The creation of market simulation models is increasingly widespread as it enables better enterprise planning and optimization of product delivery. In case of mass customization approach, which aims to simultaneously target scores of individual customers, understanding customer behavior under growing market stratification conditions is critical. This work describes development of a market simulator in which individual customers are represented as software agents, behavior of which is based on a set of predefined rules. Parameters in those rules can be either fixed or randomly follow some probabilistic distributions. Customers/agents operate in a market which offers them a line of products. These products have a set of customizable features, presumably addressing the needs of customer population. Our work describes in detail the decision process of an agent, market fragmentation design, and presents some sample results which can be used to determine desired variation offering of a product.

Quantitative Studies on the Organizational Structure of SMEs: A Case Study of Pharmaceutical Industry in China
Linlin Cui (Tsinghua University), Jin Dong (IBM China Research Lab ) and Yueting Chai (Tsinghua University)

Organizational reformation is inevitable, during the pursuing of larger scales of Small and Medium Enterprises (SMEs). In this work, a case study of the pharmaceutical industry in China is presented to show how process-based simulation can be applied to the quantitative studies on the organizational structure reformation. Through modeling core business processes and limited resources in the sales and marketing division of the enterprise, a simulation experiment is performed to analyze how the employees' working hours distribute in daily work. It is found that salesmen only spend 40% working time on the effort of marketing expansion and sales increase. It takes more than half the working time for them to track the progress of logistics affairs. So, it may be concluded that the company in the case should improve the specialization of the organizational design, and especially should consider outsourcing the professional logistics service.

Information Fusion and Component Development for Space Launch Risk Analysis
Serge N. Sala-Diakanda and Luis Rabelo (University of Central Florida)

We discussed previously the need for a risk analysis tool which could account simultaneously for the variety of hazards produced by the explosion of a space launch vehicle. We particularly argued that by analyzing separately the risks posed by the pressure of the explosion blast, the dispersion of toxic gases and the fragments cloud, current practices fail to account for the interdependencies between those hazards, potentially miscalculating the overall risk on the public and the surrounding infrastructure. In this work we set two objectives to expand on our claim. The first is to propose a methodology based on Distribution Envelope Determination (DEnv) to address the above need. The second on the other hand focuses on describing the ongoing software development activities aimed at implementing this methodology as an ArcGIS platform component.

An Object Oriented Library for Sawmill Simulation
Francisco Javier Ramis (Universidad del Bio Bio, Chile), Ivan Santelices and Felipe Baesler (Universidad del Bio Bio) and Josef Sepulveda and Reinaldo Moraga (University of Central Florida)

This work shows an object oriented library that was designed to facilitate the development of simulation studies of sawmills. A group technology approach was used to minimize the number of objects in the library, which includes objects that have the functionality of the equipments found in these facilities, so that the analyst only needs to provide the layout, locate the transports and machines, and insert the parameters of the process. For large sawmills having state of the art production equipment, with optimization capacities in each machine, two applications of the library are shown. The study demonstrates the advantage of using an object orientation, and the usefulness of simulation is a tool for aiding in both the design and in the improvement of the operations of these facilities.

Risk Analysis Using Monte Carlo Simulation and Bayesian Networks
Cláudio Flores, Fernando Makiyama, Silvia Nassar, and Paulo Jose Freitas (Federal University of Santa Catarina, Brazil) and Carlos Magno Jacinto (PETROBRAS S. A.)

The management of a global activity that has individual tasks as its components is very difficult, because an unexpected interruption in any individual task can create extra costs or even disrupt the whole activity. To resolve this problem, this work presents the development of a decision-support tool using Bayesian networks (BN). Our research illustrates how to model the relationship between the total time of a process and the time of the individual tasks selected as relevant. We use a Monte Carlo simulation to construct dynamic scenarios on the BN which allow us to track and manage a global activity. The BN is useful because the activities have random characteristics and the information about individual tasks can be propagated throughout the global activity scenario and associated with costs. This offers the administrator a tool for proactive task management and risk reduction.

Interactive Simulation and Probability Management
Sam Savage (Stanford University)

A new generation of software performs Monte Carlo simulation nearly instantaneously on arbitrary spreadsheet models. In effect, it does for probability distributions what the spreadsheet did for numbers. In addition, the concept of a Stochastic Information System is introduced, in which distributions are stored as realizations of a stochastic process. A single variable is stored as a Stochastic Information Packet (SIP), a multivariate distribution as a Stochastic Library Unit, Relationships Preserved (SLURP). This leads to the Fundamental Equality of SLURP algebra: P(F(x,y)) = F(P(x,y)) where x and y are random variables, P(x,y) is the SLURP representing their joint distribution, and F is a function of x and y. Live computer demonstrations will include distribution arithmetic, the Flaw of Averages, a retirement simulation developed for a New York trust company, and interactive portfolio model used at a major petroleum firm.

Parallel Simulations of Manufacturing Processing using SimPy, a Python-based Discrete Event Simulation Tool
Victor M Castillo (Lawrence Livermore National Laboratory)

SimPy is a Python-based, interpreted simulation tool that offers the power and convenience of Python. It is able to launch processes and sub-processes using generators, which act autonomously and may interact using interrupts. SimPy offers other advantages over competing commercial codes in that it allows for modular development, use of a version control system such as CVS, can be made self-documenting with PyDoc, and is completely extensible. The convenience of an interpreted language, however, is offset for large models by slower than desired run times. This disadvantage can be compensated for by parallelizing the system using PyMPI, from the Lawrence Livermore National Laboratory. This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

SOA-Standard-Conform Modeling as a High-Level-Standard for Discrete Simulation
Thomas Wiedemann (University of Applied Science Dresden) and Peter Eichhorst (SOCON Inc.)

Simulation models, created with leading simulation tools can not be exchanged between the systems, because there is no universal standard for discrete simulation. This results in very high investments and maintenance costs for simulation studies and some additional problems with flexibility in large simulations. A new approach seems now possible by using Service Oriented Architectures (SOA). The integration of SOA-interfaces in simulation systems connects them to the IT-infrastructure of ERP-systems, business process modeling systems and web-services. This option allows a dual use of the generated models for simulation and real control software. The SOA standards BPMN and BPEL are also capable for simulation modelling and are accepted by all major IT companies. The poster presents examples, how BPMN models can be converted to single simulation programs, which eliminates the critical performance issues of SOA-webservice interfaces. In conclusion, the SOA technology can open a new chapter in discrete simulation modelling.

Use of a Computer Algebra Software in the Functional Validation of Continuous Simulations
Yvon Resplandy (MBDA)

Due to the numeric integration algorithms with multiple iterations and the coupling effects between variables, verification and validation of simulations of continuous systems is a complex task. A method involving a Computer Algebra Software (CAS) is presented that allows preparing general parameterized test cases that cannot be achieved by hand. It applies to flat systems that are causal systems, whose outputs and states can be expressed through derivation and algebraic operations by a set of given variables (mechanical systems for example). These variables are set as temporal expressions with no or few symbolic expansion through derivation such as trigonometric or polynomial functions. Formal expressions of the inputs and outputs are calculated by means of a CAS and coded into the environment test. In addition to the verification and validation, this test is useful to assess the precision level of the integration method with respect to the variability of the inputs.

A Visual Aproach To Enhance Discrete-Event Simulation Model Interoperability
Tai-Chi Wu (I-Shou University) and Allen Greenwood (Mississippi State University)

With the continued advance of discrete-event simulation technology, various software packages have evolved that greatly facilitate the development and analysis of discrete-event simulation models. However, each of these applications uses a different approach and set of terminology for representing the behavior of the systems being studied. As a result of this disparity in implementations, models developed in different applications cannot interact with other models. Also, the disparity makes it more difficult for humans to understand the models. In this work, a visual modeling approach is proposed that allows the modeler, and those not expert in simulation, to create conceptual models that are independent of the implementation application. The approach uses eight common simulation elements. This approach facilitates the model interactions at the model formulation stage and at the application stage.

SETAC 2 Web: A Web Based Tactical Training Simulator for the Chilean Army
Luis F. Robledo (Chilean Army, Computerized Tactical Training Center(CEOTAC)), Jose Robles (Universidad del Desarrollo/ GBO Ltda.) and Juan C. Perez (GBO Ltda.)

The SETAC2WEB is a web based tactical training simulator designed for the Chilean Army to train commanders and staff officers in Decision Making Process from a Division/Brigade level to Battalion level. This system allows recreation of all phases of war, in real time, and without physical distance restrictions. SETAC2WEB is being built with state of the art technology developed between the Chilean Army and the Civilian Industry. This system has a web based and service oriented architecture with an enhanced interoperability and integration capability, MIL-STD-2525-B NATO's military coding system, authentication with digital certificate, and rich graphical user interfaces.

PLSE-Based Generic Simulation Training Platform for Typical Weapon Equipments
Ying Liu (Optical and electric engineering Department of Mechanical Engineering College)

With the development of simulation technologies, virtual training for the military has become more and more important. Combining system and software engineering theory, based on the PLSE (Product Line Software Engineering) idea and method, we analyze and design simulation training characteristics for typical field equipment. We set up the domain-oriented system architecture and implement the domain framework. The research involves: putting forward the conceptual simulation platform based on PLSE, applying the domain engineering method, analyzing commonalities in the training for typical equipment, and implementing a general architecture. Using relevant technologies, we develop reusable core assets systematically and strategically, and build the object-oriented development platform and the platform-based developing models.

In Silico Analogues of Epithelial Cell Growth and Morphogenesis
Sean H.J. Kim and Mark R. Grant (University of California, Berkeley and San Francisco) and Sunwoo Park and C. Anthony Hunt (University of California, San Francisco)

We present simulation models of in vitro cell culture systems and their application in systematic exploration of the simulated cell growth mechanisms and their impairment in epithelial morphogenesis. Our referent systems are in vitro cell cultures commonly used for studies of morphogenetic processes that underlie the development of the embryo and its organ systems. We have constructed discrete event, agent-based models with agent rules that capture posited processes of cell proliferation and death involved in the formation of multicellular epithelial structures such as cysts and tubules. We report on their application in exploring the phenotypic consequences of disabling the simulated processes, and show that varying degrees of the disablement cause different growth patterns to emerge, including a cancer-like phenotype.

Barriers To and Driving Forces for the Implementation of Manufacturing Simulation in the Swedish Foundry Industry
Patrik Thollander (IKP) and Petter Solding (Swecast)

The deregulation of the European electricity market has led to increasing electricity prices in Sweden, and prices are expected to raise even further, posing a major threat to the Swedish foundries. This study present results from a study of barriers to and driving forces for the use of manufacturing simulation and optimization methods at nine Swedish foundries. The method used is in-depth interviews and a questionnaire. The largest barriers were found to be: lack of information regarding what opportunities manufacturing simulation may gain, lack of time or other priorities, and lack of staff awareness. The largest driving forces were found to be: lowered production costs, faster production periods, and possible simulation of the daily production plan.

Conspace Simulation Application
Tarek M Zayed (Concordia University)

Simulation becomes essential in the modern world, especially for construction industry. Simulation principles are used to provide efficient solutions for different construction operations. The use of simulation packages becomes popular in modern construction technologies. Using existing packages involves training on specific applications. In addition, space constraints for different processes are not entirely presented, and when presented, the required computing resources are intense, especially for 3D simulation applications. Therefore, adding space constraints to simulation packages becomes crucial in order to accommodate the dimensions required by various resources as well as the available space in the construction operation. Consequently, Construction Space Simulation Application (CSSA) is designed to provide a solution for this space problem. The CSSA is coded using Microsoft Visual Basic 6.0 and Access. It is validated, which shows robust results.

Comparative Analysis of Process Interaction and Activity Scanning Approaches in Simulation of Construction Operations
Rita Awwad, Amir Behzadan, and Omer Tsimhoni (University of Michigan)

This work illustrates the modeling and implementation differences between Process Interaction (PI) and Activity Scanning (AS) approaches in simulation of construction operations. AS has been widely used in simulation of construction activities while PI is a common approach in simulating manufacturing and industrial operations. A rock quarry site has been chosen as a sample construction operation which inherits some degrees of uncertainty primarily in limited resource levels. The two simulation tools used are ProModel (for process interaction) and STROBOSCOPE (for activity scanning). Relevant details of implementation are described on each software in an attempt to show that both programs can sufficiently be used to model the task. We compare the results and discuss the differences.

Simulation of the Pig Iron Transportation System in Companhia Siderurgica Tubarão - Arcelor Group
Alain de Norman et d'Audenhove (Belge Engenharia e Sistemas)

The objective of this paper is to present the development of a simulation model involving materials handling in a large steel company from Arcelor Group. The project had a return of more than 2 million USD and points to a kind of application that seems to be a typical case where static analysis may cause great errors comparing to a dynamic one (because the results were also observed in another Brazilian steel company). The project focused in the processes involving pig iron transportation between the blast furnaces and its discharge in the steelmaking plant. It allowed the evaluation of several operational parameters such as for the 7.5 Mt/year production rhythm, a great increase from the actual production of 5 Mt/year. “Bottlenecks” in the flow were identified through the results and the scenarios gave the support to the decision of increasing the number of torpedo-cars and locomotives in the system.

Supply-Chain Simulation and Analysis of Petroleum Refinery Systems: A Reusable Template with Incremental Approach
Luiz Augusto Franzese, Marcelo Moretti Fioroni, and Daniel Pablo Paz (Paragon Tecnologia), Rui Carlos Botter (Universidade de São Paulo (USP)) and Carlos Alberto Gratti, Alberto Omar Martinez, and Carlos Maria Bacigalupo (Petrobras Energía S.A)

Simulation technology has been successfully applied in Supply Chain studies, mostly to assist onetime decisions, and rarely in recurrent situations. Several authors have chosen traditional approaches like developing simulators or developing templates for better modeling, facing pitfalls like lack or excess of detail, lack of flexibility of tools, how to continue to evolve models in a dynamic environment etc. This work addresses application of a systems approach to better describe and model complex processes. We also demonstrate how a combined approach of templates and simulators, described as incremental modeling, was used to create a refinery simulation toolset, and present results of an application at Petrobras Energia.

[ Return to Top | Return to Program ]