Simulation Spotlight

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Journal of SimulationMesoscopic Discrete Rate Simulation Modeling in the Automotive Industry
2020 November
Mesoscopic Discrete-Rate-Based Simulation Models for Production and Logistics Planning
Tobias Reggelin, Sebastian Lang, and Christian Schauf
Published in the Journal of Simulation
November 12, 2020

Mesoscopic vs. MicroscopicThe application of mesoscopic discrete rate simulation models for two typical planning tasks in the automotive industry are demonstrated by the authors to illustrate the capability of this modelling class to meet the requirements of logistics and production planners by providing more accurate simulation results. Typically, planning engineers solve these tasks with detailed microscopic simulation models because of the availability of object-based discrete event simulation tools in the automotive industry, which leads to complicated and slow models. However, the combined use of discrete rate and discrete event modeling in mescoscopic models can represent logistics flow processes on an aggregated level through piecewise-constant flow rates by applying the discrete rate simulation paradigm instead of modelling individual flow objects leading to fast model building and computation. Read more

IBIMA ConferenceQueue Management During a Pandemic
2020 October
Zabawa modelSimulation Approach in Queue Management at Supermarkets in the COVID-19 Era
Jacek Zabawa, Wroclaw University of Science and Technology
Presented at the 35th IBIMA Conference, Seville, Spain
April 2020

How might one both prevent and control an epidemic spreading of disease (for example COVID-19) in supermarkets? To answer this question, a simulation approach was proposed. A number of simulation experiments were performed. The likelihood of close contact with a carrier in different ticket queue configurations was compared. Based on the results, several tips and advice was developed for customers and market managers.
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Lund UniversityStructural Engineering
2020 September
Lund University - Structual Engineering ModelAn Integrated Simulation-Based Method for Considering Weather Effects on Concrete Work Tasks’ Productivity and Concrete Curing
Robert Larsson, Lund University
Research project in conjunction with the Swedish construction industry's organization for research and development (SBUF) and Cementa AB
September 2020

This report presents an integrated simulation-based approach to study the on-site production of concrete frameworks by considering the multiple effects of weather on work task productivity and concrete curing process. The ExtendSim model created reports simulated construction time, cost, and CO2 emissions for a specific construction setup to facilitate planning and decisions related to resource allocation strategies, construction schedules, different concrete types (including climate-improved concrete), and curing measures for different types of expected weather conditions.
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NABECFeedstock Supply Chain for Biofuels & Biochemicals
2020 July
MASH-PandemicsIntegrated Simulation Modeling for Supply Chain Impacts of Genetic Improvements in Switchgrass
Haley Stauffer, Pennsylvania State University
Using ExtendSim Research Grant for her Masters of Science in Agricultural and Biological Engineering
Poster presentation at the Northeast Agricultural and Biological Engineering Conference, July 2020

Using an ExtendSim Research Grant for her Masters thesis, Ms. Stauffer is providing an academic addition to the existing literature to better improve further knowledge of switchgrass supply chain needs and management. Working in conjunction with Oak Ridge National Laboratory (ORNL), The Center for Bioenergy Innovation, and the US Department of Energy's Office of Science, Ms. Stauffer submitted and was awarded first place in the poster competition at the Northeast Agricultural and Biological Engineering Conference (NABEC). Once her project is completed, ORNL will be utilizing this data to further their efforts in industrial scale research of bioenergy production from switchgrass.
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2020 May
A Portal to Support Models for Assessing Strategies for Hospitals • Responding to COVID-19 and Other Pandemics
Collaboration between George Mason University, The World Bank Group, & Johns Hopkins University

MASH-PandemicsA portal is designed to support hospitals and regional administrators in responding to the current COVID-19 pandemic and other disease outbreaks. Using mathematical modeling, this collaboration of experts provides recommendations to help hospitals adapt and coordinate to meet demand surges. MASH-Pandemics can:
• Recommend how to increase capacity by providing alternative standards of care, changing operations,or managing demand
• Assess how hospitals can work together to build strong regional responses
• Estimate and prioritize critical supply needs to mobilize supply chains and other external supports
• Measure the evolving response capacity and capability of hospitals

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Technical University of MunichAgent-Based Modeling with ExtendSim
2020 April
Usage Intensity in Life Cycle of Real Estate - Quantification of Usage Intensity by Simulation
Shujing Deng, Technischen Universität München
April 3, 2020

Shujing Deng modelTo truly estimate the life cycle of a building, it’s important to find a way to quantify the usage intensity of its individual components. Generally, many factors have an impact on the life span of the components in a building, such as product quality, maintenance, and visitor interaction with the building components, but how can you do that in a building type where user structure and interaction are too complex to analyze, such as in a shopping mall? Using ExtendSim, Shujing Deng created an agent-based model of a real shopping mall with over 100 shops on two floors. Adding the logic of a decision-making mechanism to enable the monitoring of all the interactions between customers and the main building components in the mall, the dynamics of user-space relationships within the shopping mall can be observed, exposing the usage intensity regarding building components. Running different scenarios, simulation results indicate the usage of building components mainly depends on the total number of the consumers in the mall interacting with the objects.
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Socio-Economic Planning SciencesPost-Disaster Collaboration Strategies
2019 October
Assessing Hospital System Resilience to Events Involving Physical Damage and Demand Surge
Bahar Shahverdi, Mersedeh Tariverdi, Elise Miller-Hooks
George Mason University • Department of Civil, Environmental, and Infrastructure Engineering • PhD in Transportation
Published 25 July 2019 in Socio-Economic Planning Sciences

 X X X How effective are formalized collaboration strategies when responding to a disaster incident involving mass casualties and area-wide damage? How best can patients be transferred and resources, including staff, equipment and supplies, be shared across hospitals? ExtendSim was used to help quantify hospital system resilience to pandemic, MCI, and disaster events with damage. Patient flows through 9 critical units of multiple hospitals spaced over a large metropolitan region were analyzed to determine impacts on critical resources, physical spaces, and demand. Hospital resilience to these hazard events was evaluated to show the potential of strategies involving not only transfers and resource sharing, but also joint capacity enhancement alternatives to improve post-disaster emergency health care service delivery through joint action.
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IEOMSupply Chain Sustainability
2019 June
A Simulation Study of Sustainable Agri-Food Supply Chain
Hagar Amer, Noha Galal, Khaled El-Kilany • Dept of Industrial and Management Engineering • Arab Academy for Science, Technology, and Maritime Transport
Presented at the International Conference on Industrial Engineering and Operations Management • Paris, France, July 2018

Agri-Food Supply ChainDue to the globally increasing concern of public health regarding food safety, and quality, the management of agri-food supply chains (ASC) has become even more complex given its special characteristics of perishability, uncertainty of supply and demand, and managing the carbon dioxide equivalent emissions produced throughout the supply chain due to cooling, transportation, and disposal of fresh produce. Using ExtendSim, researchers modeled a two-echelon real life supply chain to study the effect of changing order quantity under uncertain demand and lead time on a set of economic, social, and environmental performance measures. Model results help to minimize food wastage, offer higher quality fresh produce, and lower emissions while maintaining the highest profit and an acceptable service level.
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IEOMReentrant Flow Lines
2019 May
Simulation Analysis of Segmented CONWIP: Application to Reentrant Flow Lines
Yassin Shaalan, Ingy El-Khouly, and Khaled El-Kilan • Dept of Industrial and Management Engineering • Arab Academy for Science, Technology, and Maritime Transport
Presented at the International Conference on Industrial Engineering and Operations Management • March 2018

Reentrant flow linesReentrant flow lines are a special type of production flow line in which a job may visit a machine or group of machines more than once. This reentrancy characteristic results in higher variability of cycle time and throughput rates when compared to traditional production flow lines. A simulation study using ExtendSim shows that by dividing a production line into segments using different CONWIP levels affects the line performance. In fact, in some instances, compared to a single segment CONWIP and push system, using segmented CONWIP can achieve the same throughput rate in a shorter cycle time.
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Frontiers in Energy ResearchBiomass Supply Chain Design
2019 April
Simulation Modeling for Reliable Biomass Supply Chain Design Under Operational Disruptions
Bhavna Sharma1, Robin Clark, Michael R. Hilliard, and Erin G. Webb
Frontiers in Energy Research • Bioenergy & Biofuels
25 September 2018

Lignocellulosic biomass derived fuels and chemicals are a promising and sustainable supplement for petroleum-based products. Currently, the lignocellulosic biofuel industry relies on a conventional system where feedstock is harvested, baled, stored locally, and then delivered in a low-density format to the biorefinery. However, the conventional supply chain system causes operational disruptions at the biorefinery mainly due to seasonal availability, handling problems, and quality variability in biomass feedstock. Operational disruptions decrease facility uptime, production efficiencies, and increase maintenance costs. For a low-value high-volume product where margins are very tight, system disruptions are especially problematic. In this work we evaluate an advanced system strategy in which a network of biomass processing centers (depots) are utilized for storing and preprocessing biomass into stable, dense, and uniform material to reduce feedstock supply disruptions, and facility downtime in order to boost economic returns to the bioenergy industry. A database centric discrete event supply chain simulation model was developed, and the impact of operational disruptions on supply chain cost, inventory and production levels, farm metrics and facility metrics were evaluated. Three scenarios were evaluated for a 7-year time-period: (1) bale-delivery scenario with biorefinery uptime varying from 20 to 85%; (2) pellet-delivery scenario with depot uptime varying from 20 to 85% and biorefinery uptime at 85%; and (3) pellet-delivery scenario with depot and biorefinery uptime at 85%. In scenarios 1 and 2, tonnage discarded at the field edge could be reduced by increasing uptime at facility, contracting fewer farms at the beginning and subsequently increasing contracts as facility uptime increases, or determining alternative corn stover markets. Harvest cost was the biggest contributor to the average delivered costs and inventory levels were dependent on facility uptimes. We found a cascading effect of failure propagating through the system from depot to biorefinery. Therefore, mitigating risk at a facility level is not enough and conducting a system-level reliability simulation incorporating failure dependencies among subsystems is critical. Read more

yehia ieemDynamic Pricing and Inventory Management of Perishable Products
2018 December
Sustainable Dynamic Pricing for Perishable Food with Stochastic Demand
Ghada Yehia Mostafa, N.M. Galal, K.S. El-Kilany
IEEM 2018 -- International Conference on Industrial Engineering and Engineering Management
Masters in Industrial Engineering • Arab Academy for Science, Technology, and Maritime Transport

yehia foodEstablishing a pricing strategy and managing inventory of perishable products can easily be a retailer’s nightmare. How do you maximize revenue while minimizing food waste? As a product nears the end of its lifetime, will customers still purchase it at the same price as when it was fresh? If you reduce the price as the product ages, what might that price point be so customers will purchase it and you will be left with little to no waste? Or do you cut inventory so product will sell out before it ages, but leaving some customers without needed product? This paper investigates dynamic pricing strategy with the objective of maximizing revenue and minimizing food waste to ensure sustainability and customer satisfaction. Read more

ISAT 2018Forecasting Demand for Healthcare Services Using Hybrid Simulation Techniques
2018 September
Overcoming Challenges in Hybrid Simulation Design and Experiment
Jacek Zabawa and Bozena Mielczarek, Faculty of Computer Science and Management, Wroclaw University of Science and Technology
ISAT 2018 -- 39th International Conference

Zabawa modelThis study builds on earlier research which focuses on the use of combined simulation methods to support healthcare demand predictions. The authors developed a hybrid simulation model composed of two submodels which were built using different simulation paradigms. Both models, i.e. a population model based on a continuous modeling approach and an arrivals model built with discrete-event methodology, were created in ExtendSim. This combined model simulates the consequences of demographic changes, the variability in incidence rates that result from an aging population, and the seasonal fluctuations in epidemic trends on future demand for healthcare services.

OCEAN CERTAINCreating Certainty About the Contributions of our Oceans
2018 April
Ocean Certain
Ocean Certain was a collaborative EU-project from 2013-2017 consisting of 11 partners from 8 European countries plus Chile and Australia.
The project was initiated in Norway by NTNU (the project coordinator) and the University of Bergen.

OCEAN-CERTAIN was an ambitious collaborative project with natural scientists, working with the ecosystem and the biological pump, and social scientists studying possible consequences for society who worked to create more certainty about the contributions of our oceans during climate change. Climate change poses serious risks for both natural systems and human beings, and plausible and feasible policy decisions and strategies to mitigate these risks are urgently needed. However, there are important knowledge gaps surrounding the large-scale natural processes and interactions with social-economic processes that play an important role for our oceans. The multi-disciplinary project OCEAN-CERTAIN (Ocean Food-web Patrol – Climate Effects: Reducing Targeted Uncertainties with an Interactive Network) aimed to shed light on these processes.

Using a combination of metamodel simulations, system dynamics with the custom-designed GUI functionalities of ExtendSim, Ocean Certain has created a a powerful tool for the evaluation and demonstration of policy alternatives under different climate and socio-economic conditions. This decision support system was designed to serve as knowledgebase and knowledge generator to examine the feedback mechanisms linking the ocean food web system to the social-economic system of the coastal zones.Read more

PolarimeterInstrument Simulation
2018 March
Richard Morrison
University of Melbourne • School of Chemistry

Polarimeter modelSimulations offer valuable insights into how an instrument can be expected to perform and can also point to areas for improvement. In the case of polarimeters described in this article, it is of interest to simulate the motion of the analysing polarizer relative to the fixed defining polarizer as this forms the basis for the optical rotation measurements. To make the simulation more realistic the author incorporated additional factors including (i) the broadband nature of the LED’s emission spectrum, (ii) the variation of the specific rotation of the sample as a function of wavelength, (iii) the spectral response of the detector and (iv) the temperature at which measurements are performed.
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Auckland University of TechnologyPerishable and Substitutable Product Supply Chains
2018 February
Replenishment Policy for Perishable and Substitutable Products at Suppliers and Retailers: A Multi-Criteria Approach
Linh Nguyen Khanh Duong
PhD in Supply Chain Management
Auckland University of Technology • Faculty of Business and Law

duong perishableDefining replenishment policies for perishable products is an important activity, particularly where suppliers have a range of products. As product ranges increase, consumers can substitute products if their preferred product is out of stock. Such substitution considered simultaneously as perishability makes it difficult to achieve balanced results over different departments/companies in the face of fluctuating demand. Given these circumstances, a financially calculated replenishment policy makes communicating the impact of operational changes difficult. In contrast, non-financial measures improve the communication between departments and staff (e.g., between warehousing, procurement, and sales), and allows them to set operational targets from broad corporate strategies. This study contributes to inventory management theory by being the first research to develop a non-financial framework and demonstrate its comparability to financial approaches for perishable and substitutable inventory.
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WSC 18Minimizing Uncertainties in Shipbuilding
2017 December
Application of a Multi-Level Simulation Model for Aggregate and Detailed Planning in Shipbuilding
(El Astillero 4.0: Modelado y Simulación del Astillero de Navantia - Ferrol)
Mar Cebral Fernández, Marcos Rouco-Couzo, Marta Quiroga Pazos - UMI Navantia, UDC; Rafael Morgade Abeal - Navantia Ferrol; Alejandro García del Valle & Diego Crespo-Pereira - Universidade da Coruña.
Presented at the Winter Simulation Conference 2018

mfg navantiaShipbuilding is one of the most complex existing manufacturing processes. The large number of operations necessary to produce the parts that make up a vessel coupled with the need to synchronize multiple workflows and numerous resources where serial production is practically non-existent, make the management of such a production system very difficult. mfg navantiashipSimulation is an extremely powerful tool for the decision-making process to test and evaluate different scenarios, to efficiently plan future investments, to determine the allocation of resources, and to drastically reduce the risks of making incorrect decisions.

This case study uses ExtendSim to model the manufacturing process of a frigate from the shipyard of Navantia Ferr to minimize the uncertainties of its construction.
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Carollo Engineers, Inc.2017 Software & Technology Innovation Award
2017 November
Carollo’s Blue Plan-it® Team Wins 2017 Software and Technology Innovation Award
Chao-an Chiu & Charlie He, Carollo Engineers, Inc.
Corporate Vision Magazine's 2017 Software & Technology Innovation Award
Blue Plan-it Award

Carollo Engineers, Inc. Blue Plan-it® was selected from a shortlist of 200 firms for the 2017 Software Technology Innovation Award, given by Corporate Vision Magazine. This is an exceptional achievement, since that Carollo is really not a software company.

Developed by Carollo to help municipal service providers manage complex, interconnected water and wastewater infrastructure, storage, treatment, conveyance, and distribution systems, Blue Plan-it is a fully customizable simulation and optimization model suite developed in ExtendSim. Blue Plan-it takes an agency’s vast quantity of data, including maintenance, geographic, regulatory, and financial information, and creates a customized graphical user interface that can be easily modified, understood, and presented.
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APICS 2017Fortune 500 Medical Device Company
2017 October
Using Simulation and Optimization in Complex Manufacturing Operations
Jim Curry, Founder, OpStat Group Inc. & Alvaro Brisolla, Production Planning and Logistics Senior Manager, Ethicon (a Johnson & Johnson subsidiary)
APICS Annual Conference 2017

APICS 2017 modelThis presentation outlines the story of a Medical Device Fortune 500 company’s experience in implementing a combined simulation and optimization solution not integrated to the primary ERP system of a critical manufacturing location. You'll learn about the pros and cons, and the challenges and lessons learned, during the implementation process using a discrete simulation model using OpStat methodology launched in two critical areas in 2015 and 2016. After a weekly simulation and optimization process was enacted, customer service rose to unprecedented levels, while plant financial performance became enterprise benchmarks. The process knowledge acquired by the team during the implementation also resulted in a major shift in the nature of the work of the planning organization, evolving from a group of schedulers to a team of holistic capacity planners. To accomplish this task in an evidence-based way, a simulation model was developed using ExtendSim. This approach helped the clinical, managerial, and facility staff to not just understand their existing department workflow but also to provide them the opportunity to test trans-disciplinary scenarios to guide the design of the new emergency department. Furthermore it provided the client with the statistics to evaluate the impact a new Chest Pain & General Observation Center and Results Waiting Lounge would have on their entire system. Read more

EnergiesBiomass Supply Chain
2017 August
Development of the IBSAL-SimMOpt Method for the Optimization of Quality in a Corn Stover Supply Chain
Hernan Chavez & Krystel K. Castillo-Villar from the Mechanical Engineering Department at The University of Texas at San Antonio and Erin Web from the Environmental Sciences Division at Oak Ridge National Laboratory
Energies, Volume 10, Issue 8 

IBSAL-SimMOpt model
Up until now, most of the models developed to optimize biomass supply chains have failed to quantify the effect of biomass quality and the preprocessing operations required to meet biomass specifications on overall cost and performance. However, the IBSAL-SimMOpt method provides a novel approach for finding near-optimal solutions to the problem of designing biomass supply chains that improve the physical characteristics of the feedstock at an acceptable cost. The bioenergy sector and the research community now have access to a simulation-based optimization model with activity-based costing that is capable of representing the stochastic behavior of some elements intervening in the corn stover supply chain for the production of bioethanol. This analytical model can be used for decision making as well as educational and training purposes since it allows the user to conduct “what if” scenarios.
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NTNUOil & Gas Subsea Production
2017 June
Production Availability Analysis: Implications on Modelling due to Subsea Conditions
Subsea viewTianqi Sun
Masters Thesis in Reliability, Availability, Maintainability and Safety (RAMS)
Norwegian University of Science and Technology
Department of Mechanical and Industrial Engineering

Subsea production and processing systems have become a hot topic among research institutes and industries. While highlighting the advantages on production and economy, the reliability issues show a different picture with limited access, difficulty of maintenance and possibly lower availability. The influence of these issues on the system performance is studied in this paper to evaluate the benefit of subsea systems.
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SDMPH Disaster Med Public Health Preparedness
2017 February
Evaluating the Impact of Pharmacies on Pandemic Influenza Vaccine Administration
Schwerzmann J, Graitcer SB, Jester B, Krahl D, Jernigan D, Bridges CB, Miller J

Is it really beneficial for pharmacists to administer pandemic influenza vaccines? Absolutely! Using ExtendSim, researchers showed that weekly national vaccine administration capacity increased to 25 million doses per week when pharmacist vaccinators are integrated into pandemic vaccine response planning. In addition, the time to achieve 80% vaccination coverage nationally was reduced by 7 weeks, assuming high public demand for vaccination.  Read more