WSC 2006 Abstracts

Case Studies Track

Monday 10:30:00 AM 12:00:00 PM
HLA and Emulation Applications

Chair: Joseph Hugan (V-Sim, Inc.)

Using Emulation to Commission Conveyor Systems Faster at General Motors
Joseph Hugan (V-Sim, Inc.)

Over the past several years, General Motors has been using Emulation to verify and validate PLC ladder logic prior to the installation of conveyor systems. This presentation will focus on the emulation of a Tire and Wheel conveyor system and the benefits realized during project.

Automating HLA Federation Testing
John Tufarolo (Raytheon-Virtual Technology Corporation)

HLA Federation development and testing for compliance to established federation standards is a complicated, often manual process. In the course of working in a variety of federation efforts, Raytheon-VTC has developed a few techniques and applications to make this process more automated and repeatable. This case study will present and discuss those approaches.

Monday 1:30:00 PM 3:00:00 PM
Simulation Models for Oil Refineries

Chair: Guilherme Barbosa (PETROBRAS)

From Small to Complex Simulation Models: An Evolution of Sizing Refinery Tank Farms at Petrobras
Guilherme Júlio Barbosa, Cláudio Duarte Limoeiro, Guilherme Aquino Barbosa, Ana Chan, Eliahu Rosembaum, and Mario Jorge Lima (PETROBRAS)

Since 2004, a simulation-based methodology of sizing tank farms in Petrobras Refineries (Brazilian Oil Company) has been applied and has become an important analysis tool to support decisions. The methodology contributed to the development of a corporate plan to evaluate all tank farms in order to address the increasing demand for new ventures and studies according to the last directions of the strategic plan. A follow-up was the necessity to build larger models which should also represent the complexity of logistics in supplying refineries and distribution centers, besides consumers. The more precise definition of process variabilities has resulted in better results and more adherence. This case will present a sequence of some successful practical experiences (models) in an attempt to show the evolution of the methodology’s use and its benefits.

Application of a New Methodology with Stochastic Simulation for the Capacity Planning of the Tank Farm in Refineries and Terminals
Guilherme Aquino Barbosa, Claudio Duarte Limoeiro, and Guilherme Julio Barbosa (PETROBRAS S.A.), Carlos Maria Bacigalupo (PETROBRAS ENERGIA S.A.) and Eliahu Rosenbaum, Ana Chan, and Mario Jorge Lima (PETROBRAS S.A.)

This work presents the application of a methodology developed by Petrobras, using stochastic simulation, for the capacity planning of tank farms in refineries and terminals. It was based on the development of a generic model which can be customized to each site and on the possibility of doing integrated analysis with the results. Two cases will be presented: adequacy of a diesel tank farm in a Brazilian refinery to new environmental regulations, without loss of service level to the market; and a study of the impact caused in an oil tank farm by the increase of the distillation capacity of a refinery associated with a port in Argentina. In this last case, the original model was expanded with an integrated logistic sub-model representing pipeline schedules, maritime terminals and oil cabotage.

Monday 3:30:00 PM 5:00:00 PM
Applications of Theory to Practice

Chair: Luca Capriotti (Credit Suisse Investment Banking Division)

Least Squares Importance Sampling for Monte Carlo Security Pricing
Luca Capriotti (Credit Suisse Investment Banking Division)

We describe a simple Importance Sampling strategy for Monte Carlo simulations based on a least squares optimization procedure. With several numerical examples, we show that such Least Squares Importance Sampling (LSIS) provides efficiency gains comparable to the state of the art techniques, when the latter are known to perform well. However, in contrast to traditional approaches, LSIS is not limited to the determination of the optimal mean of a Gaussian sampling distribution. As a result, it outperforms other methods when the ability to adjust higher moments of the sampling distribution, or to deal with non-Gaussian or multi-modal densities, is critical to achieve variance reductions.

Practical Application of Correlated Input Models
Scott J Bury (The Dow Chemical Company)

Several previous WinterSim Conferences have featured the development of autocorrelated input models (for example see Biller WSC04, Karaman WSC04 and Nelson WSC98). Unfortunately application examples of these types of models have had limited exposure in the simulation literature. To help remedy the paucity of examples, this presentation will show the results from a study using an autocorrelated production data as an input model for an inventory forecast. The presentation includes the input model development and validation, and a comparison of results with and without autocorrelation.

Tuesday 8:30:00 AM 10:00:00 AM
Visualization and Simulation Tools for Weather Satellites

Chair: Doug Shannon (Northrop Grumman Mission Systems)

NOVA Case Study
Lloyd Matthews and Doug Shannon (Northrop Grumman Mission Systems)

Northrop Grumman Mission Systems has developed tools for simulation and visualization of weather satellite data collection and processing. The visualization tool, NOVA, supports 3-D views of astronomical objects. The simulation tool, ATDS (Algorithm Timing and Dependency Simulation), is based on the commercial Extend simulation toolkit by ImagineThat!, Inc. The combination of NOVA and ATDS has been used for system performance analysis and demonstrations on the NPOESS weather satellite program. The NOVA tool can be dynamically commanded to display satellite scan patterns by means of an IP-based text messaging interface. A custom "wrapper" Windows DLL, developed for the NPOESS program, allows Extend to access Winsock functions, permitting messaging from Extend to NOVA. This presentation will describe the interface and messages, as well as planned improvements. It will also demonstrate a NOVA 3-D animation, dynamically controlled by an Extend simulation of multiple satellite scans.

ATDS Case Study
Doug Shannon and Lloyd Matthews (Northrop Grumman Mission Systems)

Algorithm Timing and Dependency Simulation (ATDS), which is written using the commercial Extend toolkit, supports the National Polar-Orbiting Observation Environmental Satellite System (NPOESS) program. ATDS simulates multiple orbiting weather satellites, data retrieval through global receptors, and weather product generation and distribution. It simulates dynamic weather, terrain, and day/night as multiple satellites orbit the earth. This simulation is unique in its modeling of weather science with chains of interdependent algorithms. ATDS analyzes processing capacity and memory, evaluates architectural alternatives, and supports cost/quality/latency trades. ATDS is used to explore design alternatives that process data more efficiently under latency constraints. ATDS has been successfully used by NPOESS to size the architecture and evaluate cost/performance trades for five years. This demonstration animates the flow of data from satellite collection to global receptors and through processing into products. The animation displays multiple satellites orbiting the earth, and their data flowing through distributed multi-processors.

Tuesday 10:30:00 AM 12:00:00 PM
Using Simulation for Capacity Studies

Chair: Adam McNeely (Hormel Foods Corporation)

Capacity Analysis of Mechanical Test Laboratory from the CST-ARCELOR Hot Strip Mills
Ricardo Ramos (CST - Companhia Siderúrgica de Tubarão)

This case study in the CST-ARCELOR steel making plant shows how the capacity analysis of mechanical test laboratory from the Hot Strip Mills was made using simulation with the software ARENA. The goals of the study were: identify the actual capacity of the laboratory for different scenarios (production mix); analyze the system performance (queue analyses, resources utilization, answer times, etc); identify bottlenecks to invest in new production resources to improve the actual capacity and give support to the future situation (production expanding). Based on the results, it was possible to test and measure the gains of the new resources inclusions for the future production. Afterward, new configurations may be created to attend the expanding production.

Inventory Capacity Analysis of a Production Plant at Hormel Foods Corporation
Adam A. McNeely and Beth M. Bell (Hormel Foods Corporation)

Hormel Foods Corporation was experiencing problems with product flow due to over utilized inventory locations at one of its Grocery Products facilities. The product mix and number of supply items had grown since the plant’s construction creating an imbalance in the number and type of storage locations available for direct and work in process inventory. The simulation model captured current plant storage utilization over a five week production period, and then offered the ability to test alternative layout proposals. The complexity of several different systems supplying and demanding material from different bay locations at various rates, quantities and shifts of operation, made this an ideal application for simulation modeling. The simulation model provided the analyst the tools to determine the best alternative solution while verifying adequate inventory turns, minimizing equipment and material handling costs, and meeting capacity requirements.

Tuesday 1:30:00 PM 3:00:00 PM
Efficiency Improvement via Simulation

Chair: Paul Badin (

Evaluation Of Cellular Manufacturing System For LCD Monitor Assembly Line Using Simulation Analysis: A Case Study
Eoksu Sim, Sujeong Lee, Gapsoo Lee, Changhee Cho, and Jungyun Choi (Samsung Electronics)

This study compares the effectiveness in two manufacturing systems, i.e., the traditional conveyor system and cellular manufacturing system. The objective of this study is three folded. First, we propose a new type of manufacturing line using the cellular manufacturing concept. This line can be used to replace the traditional conveyor line. Second, we wish to analyze some operational logics if they can contribute to the productivity. Third, we wish to improve material flow in a plant after redesigning the layout to make the line balanced. We present a simulation study that aimed at system performance verification and demonstrated the effectiveness of the new concept.

Using Simulation to Test a New Queue Prioritization System at
Paul D. Babin (

Abstract: provides on-demand printing for a growing list of customers who order presentation and training materials online to be delivered overnight anywhere in the country. The centralized production facility uses state-of-the-art digital printing and a variety of collation and binding workstations organized into a lean production system (with high demand variability, short cycle times, and make-to-order product mix). A capacity simulation model was constructed in ProModel to support the rapid demand growth. With detailed job routings, the simulation has the capability to study system performance under different queue prioritization (job selection) rules. A new queue prioritization system, known internally as ADAP (the Adaptive Document Assembly Process), was evaluated using this simulation model. This approach of using simulation to fine tune the system provided a low-risk and repeatable platform for this important process improvement.

Tuesday 3:30:00 PM 5:00:00 PM
Simulation Diversity: From Warehousing to Medicine

Chair: Carley Jurishica (Rockwell Automation)

Modeling Perioperative Systems Flow with High Fidelity in a Team Environment
Henry Bell (Smoky Mtn Sim Services), Susan O'Hara (O'Hara Healthcare Consultants) and Mark Sullivan (Mark Sullivan Architects)

This case study focuses on the value of simulation modeling of the Perioperative healthcare processes within the facility workspace. Simulation provided a test bed for alternate process flows, policies, staffing, and resource allocation, for the cases flowing through a renovated space. The investigation yielded a cohesive view of the myriad patient flows. The study uses a large dataset (90,000+ records of 30,000+ patients) culled from hospital patient logs and electronic data collection systems. This level of fidelity increased team buy-in and increased certainty that savings estimates would be real, providing an accurate understanding of resource allocation as it relates to revenue. The effort’s positive outcome showed the importance of involving nursing staff and facility administration with the healthcare planning, architecture, and simulation modeling team. The result is improved patient care and patient flow with better use of personnel and other resources.

Warehouse Simulations: Discreetly Saving Time and Money
Carley J Jurishica (Rockwell Automation) and Sam Gallaher (Johns Manville)

A leading manufacturer of insulation and building material products uses simulation to analyze and improve a variety of processes across their enterprise. The success and visibility of recent projects has increased demand for simulation studies within the organization. We will discuss a simulation study that was used to analyze 4 different warehouses within the business. This work enabled them to evaluate alternate layouts, product placement decisions, and staffing methods for effects in safety, efficiency, as well as machine wear and tear, without the high cost of experimenting on the physical facility.

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