Simulation Spotlight

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MASH-Pandemics 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 A 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

Post-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 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.

Supply 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 Due 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.

Reentrant 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 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.

Biomass 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.

Dynamic 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 Establishing 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.

Forecasting 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 This 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.

Creating Certainty About the Contributions of our Oceans 2018 April

Ocean Certain Ocean Certain consists 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 is an ambitious collaborative project working 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) aims to shed light on these processes. OCEAN-CERTAIN is an EU FP7 project that comprises 11 partners from eight European countries, Chile and Australia. It includes both natural scientists, who will work with the ecosystem and the biological pump, and social scientists who will study possible consequences for society. 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 has been 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.

Instrument Simulation 2018 March

Polarimeter Richard Morrison University of Melbourne • School of Chemistry Simulations 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.

Perishable 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 Defining 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.

Minimizing 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 Shipbuilding 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. Simulation 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.

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 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.

Fortune 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 This 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.

Biomass 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  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.

Oil & Gas Subsea Production 2017 June

Production Availability Analysis: Implications on Modelling due to Subsea Conditions Tianqi 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.

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.