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Optimal control problem for COVID-19 with multiple time-delays in state and control

Results in Control and Optimization 2025年 19卷

作者： Mohcine El Baroudi Hassan Laarabi Samira Zouhri Mostafa Rachik Abdelhadi Abta Laboratory of Analysis Modeling and Simulation (LAMS) Mathematics and Computer Science Department Hassan II University of Casablanca Faculty of Sciences Ben M’sik Sidi Othman BP 7955 Casablanca Morocco Mathematics and Computer Science Department Poly-disciplinary Faculty Cadi Ayyad University P.O. Box 4162 Safi Morocco

The primary motivation of this paper is to identify the most effective implementation of delayed preventive measures, including active screening and testing, mask-wearing, and vaccination for COVID-19, in a way that minimizes the number of infected and exposed individuals, and maximizes the count of recovered individuals. Our goal is to comprehend the impact of delays on the epidemic’s spread and to offer guidance to health authorities on what steps to take if they implement COVID-19 preventive measures too late. We achieve this by employing optimal control theory on a SEIR model that illustrates the dynamics between susceptible, infected, exposed, and recovered individuals within the population. We set up our optimal control problem with multiple time delays in both the state and control variables, then, we used Pontryagin’s Maximum Principle to determine the solution to the delayed optimal control problem with multiple state-control constraints. Our results of simulation show that to control epidemic propagation when preventive measures are delayed, we should take immediate action after delay phase by enforcing mask wear and starting vaccinations to cover a significant portion of the population as quickly as possible. We should then implement active screening and testing measures to further control the spread.

关键词： SEIR model COVID-19 Optimal control Time delays Delayed interventions Epidemic modeling

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Negative capacitance double-gate junctionless FETs: A charge-based modeling investigation of swing, overdrive and short channel effect

arXiv

引用

arXiv 2020年

作者： Rassekh, Amin Sallese, Jean-Michel Jazaeri, Farzan Fathipour, Morteza Ionescu, Adrian M. Switzerland Ecole Polytechnique Fdrale de Lausanne Switzerland Device Simulation and Modeling Laboratory Department of Electrical and Computer Engineering University of Tehran

In this paper, an analytical predictive model of the negative capacitance (NC) effect in symmetric long channel double-gate junctionless transistor is proposed based on a charge-based model. In particular, we have investigated the effect of the thickness of the ferroelectric on the I-V characteristics. Importantly, for the first time, our model predicts that the negative capacitance minimizes short channel effects and enhances current overdrive, enabling both low power operation and more efficient transistor size scaling, while the effect on reducing subthreshold slope shows systematic improvement, with subthermionic subthreshold slope values at high current levels (0.1 µA/µm). Our predictive results in a long channel junctionless with NC show an improvement in ON current by a factor of 6 in comparison to junctionless FET. The set of equations can be used as a basis to explore how such a technology booster and its scaling will impact the main figures of merit of the device in terms of power performances and gives a clear understanding of the device physics. The validity of the analytical model is confirmed by extensive comparisons with numerical TCAD simulations in all regions of operation, from deep depletion to accumulation and from linear to saturation. Copyright © 2020, The Authors. All rights reserved.

关键词： Field effect transistors

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Leveraging Ligand Steric Demand to Control Ligand Exchange and Domain Composition in Stratified Metal–Organic Frameworks

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Angewandte Chemie 2024年第42期136卷

作者： Yiwen He Mattheus De Souza Tian-Yi Luo Siddarth K. Achar Prof. Dr. J. Karl Johnson Prof. Dr. Nathaniel L. Rosi Department of Chemistry University of Pittsburgh Pittsburgh Pennsylvania 15260 United States Computer Modeling & Simulation Program University of Pittsburgh Pittsburgh Pennsylvania 15261 United States Department of Chemical and Petroleum Engineering University of Pittsburgh Pittsburgh Pennsylvania 15261 United States

Incorporating diverse components into metal–organic frameworks (MOFs) can expand their scope of properties and applications. Stratified MOFs (sMOFs) consist of compositionally unique concentric domains (strata), offering unprecedented complexity through partitioning of structural and functional components. However, the labile nature of metal-ligand coordination handicaps achieving compositionally distinct domains due to ligand exchange reactions occurring concurrently with secondary strata growth. To achieve complex sMOF compositions, characterizing and controlling the competing processes of new strata growth and ligand exchange are vital. This work systematically examines controlling ligand exchange in UiO-67 sMOFs by tuning ligand sterics. We present quantitative methods for assessing and visualizing the outcomes of strata growth and ligand exchange that rely on high-angle annular dark-field images and elemental mapping via scanning transmission electron microscopy-energy dispersive X-ray spectroscopy. In addition, we leverage ligand sterics to create ‘blocking layers’ that minimize ligand exchange between strata which are particularly susceptible to ligand exchange and inter-strata ligand mixing. Finally, we evaluate strata compositional integrity in various solvents and find that sMOFs can maintain their compositions for >12 months in some cases. Collectively, these studies and methods enhance understanding and control over ligand placement in multi-domain MOFs, factors that underscore careful tunning of properties and function.

关键词： metal–organic frameworks porous materials core–shell materials ligand exchange

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CHANCES AND CHALLENGES OF CHATGPT AND SIMILAR MODELS FOR EDUCATION IN M&S

TechRxiv

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TechRxiv 2023年

作者： Scherer, William T. Tolk, Andreas Loper, Margaret L. Barry, Philip Rabadi, Ghaith Yilmaz, Levent The MITRE Corporation Modeling and Analysis Innovation Center 1001 Research Park Blvd #200 CharlottesvilleVA22911 United States Georgia Tech Research Institute Georgia Institute of Technology AtlantaGA30308 United States University of Virgina Department of Systems and Information Engineering CharlottesvilleVA22904 United States L3Harris Corporation Mission Analysis Group 2235 Monroe Street HerndonVA20171 United States University of Central Florida School of Modeling Simulation and Training 3100 Technology Pkwy OrlandoFL32826 United States Auburn University Samuel Ginn College of Engineering Computer Science and Software Engineering AuburnAL36849 United States

The position paper summarizes the inputs of a set of experts from academia and industry presenting their view on chances and challenges of using ChatGPT within the Modelling and simulation education. They also address the need to evaluate continuous education as well as education of faculty members to address scholastic challenges and opportunities while meeting the expectation of industry. © 2023, CC BY.

关键词： modeling languages

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Analyzing the productivity of GitHub teams based on formation phase activity

arXiv

引用

arXiv 2020年

作者： Saadat, Samaneh Newton, Olivia B. Sukthankar, Gita Fiore, Stephen M. Department of Computer Science University of Central Florida OrlandoFL United States School of Modeling Simulation and Training University of Central Florida OrlandoFL United States Department of Philosophy School of Modeling Simulation and Training University of Central Florida OrlandoFL United States

Our goal is to understand the characteristics of high-performing teams on GitHub. Towards this end, we collect data from software repositories and evaluate teams by examining differences in productivity. Our study focuses on the team formation phase, the first six months after repository creation. To better understand team activity, we clustered repositories based on the proportion of their work activities and discovered three work styles in teams: toilers, communicators, and collaborators. Based on our results, we contend that early activities in software development repositories on GitHub establish coordination processes that enable effective collaborations over time. Copyright © 2020, The Authors. All rights reserved.

关键词： Software design

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Discriminatory or Samaritan - which AI is needed for humanity? An Evolutionary Game Theory Analysis of Hybrid Human-AI populations

arXiv

引用

arXiv 2023年

作者： Booker, Tim Miranda, Manuel Moreno López, Jesús A. Fernández, José María Ramos Reddel, Max Widler, Valeria Zimmaro, Filippo Antonioni, Alberto Han, The Anh Complexity Science Hub Vienna Austria IFISC UIB CSIC Spain Universidad de La Laguna Spain Department of Emerging Technology Governance International Center for Future Generations Belgium Modeling and Simulation of Complex Processes Zuse Institute Berlin Germany Department of Mathematics University of Bologna Italy Department of Computer Science University of Pisa Italy Department of Mathematics University Carlos III de Madrid | UC3M Spain School of Computing Engineering and Digital Technologies Teesside University United Kingdom

As artificial intelligence (AI) systems are increasingly embedded in our lives, their presence leads to interactions that shape our behaviour, decision-making, and social interactions. Existing theoretical research has primarily focused on human-to-human interactions, overlooking the unique dynamics triggered by the presence of AI. In this paper, resorting to methods from evolutionary game theory, we study how different forms of AI influence the evolution of cooperation in a human population playing the one-shot Prisoner’s Dilemma game in both well-mixed and structured populations. We found that Samaritan AI agents that help everyone unconditionally, including defectors, can promote higher levels of cooperation in humans than Discriminatory AI that only help those considered worthy/cooperative, especially in slow-moving societies where change is viewed with caution or resistance (small intensities of selection). Intuitively, in fast-moving societies (high intensities of selection), Discriminatory AIs promote higher levels of cooperation than Samaritan AIs. © 2023, CC BY.

关键词： Decision making

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Itinerary Recommendation for User Groups in Temporary Social Network 15th

Itinerary Recommendation for User Groups in Temporary Social...

引用

15th EAI International Conference on Collaborative Computing: Networking, Applications and Worksharing, CollaborateCom 2019

作者： Xia, Jing Li, Yu Yin, Yuyu School of Computer Hangzhou Dianzi University Hangzhou310018 China Key Laboratory of Complex Systems Modeling and Simulation of Ministry of Education Hangzhou310018 China

ISBN: (纸本)9783030301453

Temporary social network has been a increasing popular field in the last few years where people form a temporary social group for a short time period with common interests or purposes in the same area. When a user attends an event or conference in a new city, he/she can join the temporary social networks with his/her social account. Users who attend the same academic conference or activity may have similar interests and time schedules, so they are willing to travel together. Recently, renting cars to travel has become very common, since it helps improve user experience as well as save travel costs (e.g., renting and oil costs). Thus, we propose a group-wise itinerary planning framework to minimize the travel costs for each user in a temporary social network. Experimental results conducted on real-world data sets confirm the efficiency and effectiveness of our proposed framework. © 2019, ICST Institute for computer Sciences, Social Informatics and Telecommunications Engineering.

关键词： Mobile computing

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“Surgical Gps” Proof of Concept for Scoliosis Surgery

“Surgical Gps” Proof of Concept for Scoliosis Surgery

引用

Spring simulation Conference (SpringSim)

作者： Austin Tapp Michel Audette Electrical Computer & Biomedical Engineering Old Dominion University Norfolk VA USA Computational Modeling & Simulation Engineering Old Dominion University Norfolk VA USA

ISBN: (数字)9781565553705

ISBN: (纸本)9781728163642

Scoliotic deformities may be addressed with either anterior or posterior approaches for scoliosis correction procedures. While typically quite invasive, the impact of these operations may be reduced through the use of computer-assisted surgery. A combination of physician-designated anatomical landmarks and surgical ontologies allows for real-time intraoperative guidance during computer-assisted surgical interventions. Predetermined landmarks are labeled on an identical patient model, which seeks to encompass vertebrae, intervertebral disks, ligaments, and other soft tissues. The inclusion of this anatomy permits the consideration of hypothetical forces that are previously not well characterized in a patient-specific manner. Updated ontologies then suggest procedural directions throughout the surgical corridor, observing the positioning of both the physician and the anatomical landmarks of interest at the present moment. Merging patient-specific models, physician-designated landmarks, and ontologies to produce real-time recommendations magnifies the successful outcome of scoliosis correction through enhanced pre-surgical planning, reduced invasiveness, and shorted recovery time.

关键词： Solid modeling Surgery Ontologies Deformable models Computational modeling Ligaments Finite element analysis

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Enforcing security and privacy in distributed ledgers by intel SGX

Enforcing security and privacy in distributed ledgers by int...

引用

2020 Spring simulation Multiconference, SpringSim 2020

作者： Liang, Xueping Shetty, Sachin Foytik, Peter Tosh, Deepak Department of Engineering and Computer Science Virginia State University 1 Hayden St PetersburgVA23806 United States Virginia Modeling Analysis and Simulation Center Old Dominion University 1030 University Blvd SuffolkVA23435 United States Department of Computer Science University of Texas at El Paso 500 W University Ave El PasoTX79968 United States

ISBN: (纸本)9781713812883

Distributed Ledger Technology (DLT) utilizes an architecture that can host a large number of nodes without pre-established trust to provide decentralized services. The blockchain is the most widely used architecture of distributed ledger, where transactions across the whole network are visible to all participants in a chain to prevent tampering. However, transactions may contain sensitive information such as business contract. To secure the system and protect user privacy, we propose a multi-channel architecture that leverages Intel Software Guard Extensions (SGX). We illustrate how SGX capabilities help to defend against attacks on distributed ledgers, by way of SGX enforcement on the participating machines. We adopt the design and implementation of a two layer architecture for securing the blockchain mining process and enhancing the transaction privacy. The security analysis and performance evaluation show that the design and protocols are capable of protecting privacy, defending against adversarial attacks and scalable. © 2020 Society for modeling & simulation International (SCS)

关键词： Blockchain

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Simulating temporal dynamics in cryptocurrency software social networks 25

Simulating temporal dynamics in cryptocurrency software soci...

引用

25th Americas Conference on Information Systems, AMCIS 2019

作者： Chung, Wingyan Vora, Mehul Liu, Jinwei Huang, Yifan Mustaine, Elizabeth Lai, Vincent S. School of Modeling Simulation and Training University of Central Florida United States School of Modeling Simulation and Training University of Central Florida United States School of Modeling Simulation and Training University of Central Florida United States Department of Sociology University of Central Florida United States Department of Computer Science University of Hong Kong Hong Kong School of Modeling Simulation and Training University of Central Florida United States Department of Decision Sciences and Managerial Econ. Chinese University of Hong Kong Hong Kong Department of Decision Sciences and Managerial Econ. Chinese University of Hong Kong Hong Kong

Cryptocurrency, which relies on decentralized computer software programs to manage monetary transactions, has been associated strongly with illegal money laundering on the dark web. Understanding the social networks of the cryptocurrency software development communities can provide useful investigative leads and business intelligence. However, research in modeling software social networks (SSNs) of cryptocurrency software development is not widely available. This research developed three temporal network models to predict and to simulate the activities of cryptocurrency SSNs over time. The models capture the activity history of the SSNs and dynamically combine the pricing information of the related cryptocurrencies to enhance the accuracy of prediction and fidelity of simulation. We used the models to predict and simulate the SSNs of 83,536 repositories that are related to the three cryptocurrencies: Bitcoin, Monero, and Ethereum. Experimental results show that the model (SEAM) that captures recency / primacy effects of human cognitive processing outperformed other models in metrics pertaining to influence, popularity, and engagement. The research should enhance understanding of online behavior of the SSN community and identify relationship between SSNs and cryptocurrency market. © 2019 Association for Information Systems. All rights reserved.

关键词： Social sciences computing

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