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arXiv 2021年

作者： Cianfanelli, Leonardo Parise, Francesca Acemoglu, Daron Como, Giacomo Ozdaglar, Asuman Dipartimento di Scienze Matematiche Politecnico di Torino Italy Department of Electrical and Computer Engineering Cornell University United States Department of Economics Massachusetts Institute of Technology MIT United States Department of Automatic Control Lund University Sweden Department of Electrical Engineering and Computer Science MIT United States

The recent COVID-19 pandemic highlighted the need of non-pharmaceutical interventions in the first stages of a pandemic. Among these, lockdown policies proved unavoidable yet extremely costly from an economic perspective. To better understand the tradeoffs between economic and epidemic costs of lockdown interventions, we here focus on a simple SIR epidemic model and study lockdowns as solutions to an optimal control problem. We first show numerically that the optimal lockdown policy exhibits a phase transition from suppression to mitigation as the time horizon grows, i.e., if the horizon is short the optimal strategy is to impose severe lockdown to avoid diffusion of the infection, whereas if the horizon is long the optimal control steers the system to herd immunity to reduce economic loss. We then consider two alternative policies, motivated by government responses to the COVID-19 pandemic, where lockdown levels are selected to either stabilize the reproduction number (i.e., "flatten the curve") or the fraction of infected (i.e., containing the number of hospitalizations). We compute analytically the performance of these two feedback policies and compare them to the optimal control. Interestingly, we show that in the limit of infinite horizon stabilizing the number of infected is preferable to controlling the reproduction number, and in fact yields close to optimal performance. Copyright © 2021, The Authors. All rights reserved.

关键词： Optimal control systems

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Retraction Note: EoT-driven hybrid ambient assisted living framework with naïve Bayes–firefly algorithm

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Neural Computing and Applications 2024年第24期36卷 15215-15215页

作者： Hassan, Mohammed K. Desouky, Ali I. El Badawy, Mahmoud M. Sarhan, Amany M. Elhoseny, Mohamed Gunasekaran, M. Department of Computer Engineering and Systems Faculty of Engineering Mansoura University Mansoura City Egypt Department of Computer Engineering and Automatic Control Faculty of Engineering Tanta University Tanta Egypt Faculty of Computers and Information Mansoura University Mansoura Egypt University of California Davis USA

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Empirical Risk Minimization with Relative Entropy Regularization: Optimality and Sensitivity Analysis

arXiv

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arXiv 2022年

作者： Perlaza, Samir M. Bisson, Gaetan Esnaola, Iñaki Jean-Marie, Alain Rini, Stefano INRIA 2004 Route des Lucioles Sophia Antipolis06902 France The Laboratoire de Mathématiques GAATI Université de la Polynésie Française BP 6570 Faaa98702 French Polynesia The Department of Automatic Control and Systems Engineering University of Sheffield Sheffield United Kingdom The Department of Electrical and Computer Engineering National Chao Tung University Hsinchu Taiwan The Department of Electrical and Computer Engineering Princeton University PrincetonNJ08544 United States

The optimality and sensitivity of the empirical risk minimization problem with relative entropy regularization (ERM-RER) are investigated for the case in which the reference is a σ-finite measure instead of a probability measure. This generalization allows for a larger degree of flexibility in the incorporation of prior knowledge over the set of models. In this setting, the interplay of the regularization parameter, the reference measure, the risk function, and the empirical risk induced by the solution of the ERM-RER problem is characterized. This characterization yields necessary and sufficient conditions for the existence of regularization parameters that achieve arbitrarily small empirical risk with arbitrarily high probability. Additionally, the sensitivity of the expected empirical risk to deviations from the solution of the ERM-RER problem is studied. Dataset-dependent and dataset-independent upper bounds on the absolute value of the sensitivity are presented. In a special case, it is shown that the expectation (with respect to the datasets) of the absolute value of the sensitivity is upper bounded, up to a constant factor, by the square root of the lautum information between the models and the datasets. © 2022, CC BY.

关键词： Sensitivity analysis

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Performance evaluation for ranking-based discretisation

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Procedia computer Science 2020年 176卷 3335-3344页

作者： Grzegorz Baron Urszula Stańczyk Department of Graphics Computer Vision and Digital Systems Faculty of Automatic Control Electronics and Computer Science Silesian University of Technology Akademicka 2A 44-100 Gliwice Poland

Discretisation often constitutes a part of initial data preparation stage. It translates continuous domain of features into granular, by assigning a number of intervals to represent attributes’ values by nominal categories. Typically all real-valued features are subjected to transformations, regardless of their characteristics. The paper presents research on discretisation executed with a discerning approach. To all available attributes, feature selection mechanisms were employed, in the form of rankings that order variables based on their importance. Exploiting this discovered knowledge on attributes, discretisation was then driven by a ranking, and either highest or lowest ranking features were selected for transformation. The influence of selective discretisation on the performance of classification systems was studied for three popular inducers. The procedure was employed in the field of stylometry, and a task of authorship recognition, considered as a binary classification with balanced classes. The experiments show that discretisation based on importance of features can lead to better performance than in the case of transformations applied to all attributes.

关键词： discretisation feature selection ranking importance of attributes stylometry classification

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Heat Transfer Optimization of end Winding Rotor Generator by the Use of Modified Axial Spacer: A Case Study 1

Heat Transfer Optimization of end Winding Rotor Generator by...

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1st International Conference on Industrial Automation, Smart Grid and its Application, ICIASGA 2020

作者： Baskoro, Y. Jaya, I. Glowacz, A. Sulowicz, M. Caesarendra, W. PT Indonesia Power Indonesia Department of Automatic Control and Robotics AGH University of Science and Technology Kraków30-059 Poland Institute of Electromechanical Energy Conversion Faculty of Electrical and Computer Engineering Cracow University of Technology Warszawska 24 Cracow31-155 Poland Faculty of Integrated Technologies Universiti Brunei Darussalam Jalan Tungku Link Gadong Brunei Darussalam BE1410 Brunei

This paper presents a case study of a rotor fault occurring in the rotor generator of a steam power plant located in Lontar, Banten Province, Indonesia. The steam power plant has 3 x 315 MV capacity and uses hydrogen in the cooling system. The issue arising during the operation was caused by heat transfer exceeding the normal level. The grounding of the rotor occurred through rising vibration and temperature, tripping the generator unit. During repairs, the axial spacer was replaced with a new model, where it is longer than the original, adding a bar spacer at a previously unavailable position and creating a cooling track profile. This is a case study on the replacement of the axial spacer model aimed at preventing the expansion of the winding, so as not to touch with each other, through the installation of a longer axial spacer and the addition of the spacer bar, and lastly adding the track profile to the cooling hydrogen gas flow thereby maximizing the cooling process from the end winding rotor generator. Heat transfer is an analysed parameter related to the model change of the axial spacer. The addition of a track cooling gas flow has been able to maximize the heat transfer process, which is simulated in this paper. The performance of the rotor generator increased through several parameters after the replacement of the axial spacer model. © Published under licence by IOP Publishing Ltd.

关键词： Cooling

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Parameters of Guaranteed Self-Excitation of an Induction Generator for Autonomous Electric Power Sources 25

Parameters of Guaranteed Self-Excitation of an Induction Gen...

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25th IEEE International Conference on Problems of Automated Electric Drive. Theory and Practice, PAEP 2020

作者： Chenchevoi, Volodymyr Zachepa, Iurii Chencheva, Olga Yatsiuk, Rostyslav Kremenchuk Mykhailo Ostrohradskyi National University Department of Systems of Automatic Control and Electric Drive Kremenchuk Ukraine Ostrohradskyi National University Manufacturing Engineering Department Kremenchuk Mykhailo Kremenchuk Ukraine Kremenchuk Mykhailo Ostrohradskyi National University Department of Automation and Computer-Integrated Technologies Kremenchuk Ukraine

ISBN: (纸本)9781728199351

The article simulates the process of self-excitation of an autonomous induction generator by the method of regression equations, which adequately describe the dependence of the time of self-excitation and the magnitude of the output voltage. Statistically significant factors such as excitation capacity, rotor speed, residual magnetization and residual voltage across the capacitors and their influence on the qualitative and quantitative characteristics of the excitation process of an asynchronous generator as part of autonomous sources of electricity are determined. © 2020 IEEE.

关键词： Asynchronous generators

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A Distributed control framework for the optimal operation of DC microgrids

arXiv

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arXiv 2022年

作者： Fu, Zao Cucuzzella, Michele Cenedese, Carlo Yu, Wenwu Scherpen, Jacquelien M.A. School of Cyber Science and Engineering Southeast University Nanjing211189 China Faculty of Science and Engineering University of Groningen Groningen9747 AG Netherlands Department of Electrical Computer and Biomedical Engineering University of Pavia Pavia27100 Italy Automatic Control Laboratory Department of Electrical Engineering and Information Technology ETH Zürich Physikstrasse 3 Zürich8092 Switzerland

In this paper we propose an original distributed control framework for DC mcirogrids. We first formulate the (optimal) control objectives as an aggregative game suitable for the energy trading market. Then, based on the dual theory, we analyze the equivalent distributed optimal condition for the proposed aggregative game and design a distributed control scheme to solve it. By interconnecting the DC mcirogrid and the designed distributed control system in a power preserving way, we steer the DC microgrid's state to the desired optimal equilibrium, satisfying a predefined set of local and coupling constraints. Finally, based on the singular perturbation system theory, we analyze the convergence of the closed-loop system. The simulation results show excellent performance of the proposed control framework. © 2022, CC BY-NC-SA.

关键词： Perturbation techniques

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Intelligent Technologies for Ecomonitoring Data Processing in Conditions of Technogenic Emergencies

Intelligent Technologies for Ecomonitoring Data Processing i...

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International Conference on Modern Electrical and Energy Systems (MEES)

作者： Volodymyr Bakharev Andrii Perekrest Volodymyr Chenchevoi Olga Chencheva Svitlana Malyk Domanetskyi Andrii Department of Civil and Labour Safety Geodesy and Land Management Kremenchuk Mykhailo Ostrohradskyi National University Kremenchuk Ukraine Department of Computer Engineering and Electronics Kremenchuk Mykhailo Ostrohradskyi National University Kremenchuk Ukraine Department of Systems of Automatic Control and Electric Drive Kremenchuk Mykhailo Ostrohradskyi National University Kremenchuk Ukraine Kremenchug Medical College named after V.I. Lytvynenko Kremenchuk Ukraine

ISBN: (纸本)9798350346848

The paper considers the importance of expanding the possibilities of environmental monitoring of environmental air parameters in the event of man-made emergencies. Software and hardware solutions have been developed for visualization and analysis of data from public environmental monitoring systems in normal and emergency situations using Power BI and Vaisala devices. The integration of various subsystems for measuring atmospheric air and microclimate indicators in a single computer system with a single software interface was carried out.

关键词： Atmospheric measurements Surface contamination Hydrogen Software Pollution measurement Environmental monitoring Sulfur

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Sliding Mode control for a DC-DC Buck Converter Feeding a Constant Power Load: A Practical Implementation

Sliding Mode Control for a DC-DC Buck Converter Feeding a Co...

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Advanced Technology in Electronic and Electrical Engineering (ICATEEE), International Conference of

作者： Khalil Louassaa Aissa Chouder Mahdi Boukerdja Abdelhafid Cherifi Ali Aillane Electrical Engineering Department Electrical Engineering Laboratory University of M’sila M’sila Algeria Materials and Electronic Systems Laboratory University of Bordj Bou Arreridj Bordj Bou Arreridj Algeria Laboratory of Sciences and Techniques of Automatic Control and Computer Engineering (LabSTA) National School of Engineering of Sfax (ENIS) University of Sfax Sfax Tunisia

DC microgrids have gained in popularity in recent years due to features such as greater reliability, high efficiency, and control simplicity. Constant power loads (CPLs), on the other hand, are a problem and an effective cause of instability in DC MGs. To address the aforementioned issue, this paper discusses the stabilization of a buck power converter that supplies CPL via a regulated boost power converter. A robust sliding mode control is proposed, which stabilizes the output voltage and ensures the CPL's required power. The system is investigated in the context of external perturbations such as fluctuating input voltage and sudden change in the CPL. The robustness and efficacy of the proposed method have been demonstrated to confirm the system's overall stability. Simulation and experimentation are employed to verify the provided controller. The results verify the suggested controller's superiority.

关键词： Damping Voltage measurement Perturbation methods Microgrids Stability analysis Robustness Steady-state

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The forgotten document-oriented database management systems: An overview and benchmark of native XML DODBMSes in comparison with JSON DODBMSes

arXiv

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arXiv 2021年

作者： Truică, Ciprian-Octavian Apostol, Elena-Simona Darmont, Jérôme Pedersen, Torben Bach Computer Science and Engineering Department Faculty of Automatic Control and Computers University Politehnica of Bucharest Romania Department of Computer Science Aarhus University Aarhus Denmark Université de Lyon ERIC UR 3083 Lyon 2 France Center for Data Intensive Systems Aalborg University Aalborg Denmark

In the current context of Big Data, a multitude of new NoSQL solutions for storing, managing, and extracting information and patterns from semi-structured data have been proposed and implemented. These solutions were developed to relieve the issue of rigid data structures present in relational databases, by introducing semi-structured and flexible schema design. As current data generated by different sources and devices, especially from IoT sensors and actuators, use either XML or JSON format, depending on the application, database technologies that store and query semi-structured data in XML format are needed. Thus, Native XML Databases, which were initially designed to manipulate XML data using standardized querying languages, i.e., XQuery and XPath, were rebranded as NoSQL Document-Oriented Databases Systems. Currently, the majority of these solutions have been replaced with the more modern JSON based Database Management Systems. However, we believe that XML-based solutions can still deliver performance in executing complex queries on heterogeneous collections. Unfortunately nowadays, research lacks a clear comparison of the scalability and performance for database technologies that store and query documents in XML versus the more modern JSON format. Moreover, to the best of our knowledge, there are no Big Data-compliant benchmarks for such database technologies. In this paper, we present a comparison for selected Document-Oriented Database Systems that either use the XML format to encode documents, i.e., BaseX, eXist-db, and Sedna, or the JSON format, i.e., MongoDB, CouchDB, and Couchbase. To underline the performance differences we also propose a benchmark that uses a heterogeneous complex schema on a large DBLP corpus. © 2021, CC BY.

关键词： XML

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