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EFFECTIVE DYNAMICS OF A COUPLED MICROSCOPIC-MACROSCOPIC STOCHASTIC SYSTEM

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Acta Mathematica Scientia 2010年第6期30卷 2064-2076页

作者：任剑付红波曹道民段金桥 School of Mathematics and Statistics Huazhong University of Science and Technology institute of Applied Mathematics Chinese Academy of Sciences Department of Applied Mathematics Illinois Institute of Technology

A conceptual model for microscopic-macroscopic slow-fast stochastic systems is considered. A dynamical reduction procedure is presented in order to extract effective dynamics for this kind of systems. Under appropriate assumptions, the effective system is shown to approximate the original system, in the sense of a probabilistic convergence.

关键词： microscopic-macroscopic system stochastic partial differential equations averaging principle effective dynamics slow-fast scales

Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin Fang Zhikang Shuai Yang Li Zhibing Wang Xiangyang Wu Xia Shen Z.John Shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or collapse.In previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control theory.The specific mechanisms of the instability of the cascade system have not been intuitively clarified.In this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(Z=R+jX)of source and load converters.It reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(R<0)of the port the overall impedance amplifies the internal resonance source at reactance zero-crossing frequency.The simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(R<0),there exists no zero-crossing point of the reactance component(i.e.,X=0).According to the proposed stability criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability margin.Thus,the impedance reshaping method for stability improvement of the system can be further specified.The validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

Generic Modeling and Control Framework for Power Systems Dominated by Power Converters Connected Through a Passive Transmission and Distribution Grid

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 292-301页

作者： Qing-Chang Zhong Marcio Stefanello Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA Syndem LLC USA.M.Stefanello is with the Fundacao Universidade Federal do Pampa at AlegreteRS97546-550Brazil

In this paper,a compact mathematical model having an elegant structure,together with a generic control framework,are proposed for generic power systems dominated by power converters that are interconnected through a passive transmission and distribution(T&D)grid,by adopting the port-Hamiltonian(pH)systems theory and the fundamental circuit theory.The models of generic T&D lines are developed and then the model of a generic T&D grid is established.With the proposed control framework,the controlled converters are proven to be passive and Input-to-State Stable(ISS).The compact mathematical model is scalable and can be applied to power systems with multiple power electronic converters with generic passive controllers,passive local loads,and different types of passive T&D lines connected in a meshed configuration without self-loops,so it is very generic.Moreover,the resulting power system is proven to be ISS as well.The analysis is carried out without assumptions on constant frequency/voltage,constant loads,and/or lossless networks,except the need of passivity for all parts involved,and without using the Clarke/Park transformations or the graph theory.To simplify the presentation,three-phase balanced systems are adopted but the results can be easily adapted for single-phase or unbalanced three-phase systems.

关键词： Input-to-State Stable(ISS) passivity,portHamiltonian(pH)systems Power electronic converters dominated power systems Synchronized and Democratized(SYNDEM)grid architecture

Intrinsically Stretchable Electroluminescent Materials and Devices

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CCS Chemistry 2024年第6期6卷 1360-1379页

作者： Wei Liu Glingna Wang Sihong Wang Pritzker School of Molecular Engineering The University of ChicagoChicagoIllinois 60637 Nanoscience and technology Division and Center for Molecular Engineering Argonne National LaboratoryLemontIllinois 60439

Intrinsically stretchable electroluminescent(EL)devices have emerged as pivotal components with transformative potential in various domains,including wearable technology,medical devices,human-machine interfaces,and communications.This mini-review focuses on the recent progress in the development of intrinsically stretchable EL materials,highlighting milestones and breakthroughs in the field.The article discusses the basic principles,advantages,and disadvantages associated with various EL mechanisms and materials.Specific material design strategies,particularly focusing on light-emitting layers,are thoroughly examined,detailing their implementation in EL devices and the resultant EL performance.We also provide perspectives on the active challenges and future research needs for each type of EL material and devices for achieving stretchable designs,together with some insights into the future trajectory of stretchable EL technology.

关键词： stretchable electronics electroluminescent materials electroluminescent devices lightemitting diodes thermally activated delayed fluorescence

A DELAY-DEPENDENT STABILITY CRITERION FOR NONLINEAR STOCHASTIC DELAY-INTEGRO-DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2011年第5期31卷 1813-1822页

作者：牛原玲张诚坚段金桥 School of Mathematics and Statistics Huazhong University of Science and Technology School of Mathematics Central South University Department of Applied Mathematics Illinois Institute of Technology Chicago IL 60616 USA

A type of complex systems under both random influence and memory effects is considered. The systems are modeled by a class of nonlinear stochastic delay-integrodifferential equations. A delay-dependent stability criterion for such equations is derived under the condition that the time lags are small enough. Numerical simulations are presented to illustrate the theoretical result.

关键词： complex systems under uncertainty mean-square exponential stability stochastic delay-integro-differential equations memory effects numerical experiment

Cost-effective synthesis of giant molecule acceptors(GMAs)for stable polymer solar cells

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Science China Chemistry 2024年第4期67卷 1041-1043页

作者： Antonio Facchetti Department of Chemistry and the Materials Research Center Northwestern University2145 Sheridan Road60208 EvanstonIllinoisUSA School of Materials Science and Engineering Georgia Institute of Technology771 Ferst Drive30332 AtlantaGeorgiaUSA

Polymer solar cells(PSCs)have emerged as a disruptive energy technology due to simple device architecture,earthabundant elemental composition,lightweight nature,and inherent mechanical flexibility[1,2].Via a strategic acceptordonor-acceptor(A-D-A)design of small-molecule acceptors(SMAs),device power conversion efficiency(PCE)has now increased>19%.

关键词： acceptor synthesis donor

Recent Progress in Reinforcement Learning and Adaptive Dynamic Programming for Advanced Control Applications

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 18-36页

作者： Ding Wang Ning Gao Derong Liu Jinna Li Frank L.Lewis IEEE the Faculty of Information technology Beijing Key Laboratory of Computational Intelligence and Intelligent SystemBeijing Laboratory of Smart Environmental Protectionand Beijing Institute of Artificial IntelligenceBeijing University of TechnologyBeijing 100124China the School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen 518055China the Department of Electrical and Computer Engineering University of Illinois at ChicagoChicago IL 60607 USA the School of Information and Control Engineering Liaoning Petrochemical UniversityFushun 113001China the UTA Research institute the University of Texas at ArlingtonArlington TX 76118 USA

Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, respectively.Then, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation significantly.Finally, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.

关键词： Adaptive dynamic programming(ADP) advanced control complex environment data-driven control event-triggered design intelligent control neural networks nonlinear systems optimal control reinforcement learning(RL)

Secure and Reliable Routing in the Internet of Vehicles Network:AODV-RL with BHA Attack Defense

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 633-659页

作者： Nadeem Ahmed Khalid Mohammadani Ali Kashif Bashir Marwan Omar Angel Jones Fayaz Hassan School of Electronic Science Beijing University of Post and TelecommunicationBeijing100086China Department of Computer Science Huanggang Normal UniversityHuanggangChina Department of Computing and Mathematics Manchester Metropolitan UniversityManchesterUK Woxsen School of Business Woxsen UniversityHyderabad502345India Department of Computer Science and Mathematics Lebanese American UniversityBeirutLebanon Information technology and Management Illinois Institute of TechnologyChicagoUSA College of Computing Capital Technology UniversityLaurelUSA

Wireless technology is transforming the future of transportation through the development of the Internet of Vehicles(IoV).However,intricate security challenges are intertwinedwith technological progress:Vehicular ad hoc Networks(VANETs),a core component of IoV,face security issues,particularly the Black Hole Attack(BHA).This malicious attack disrupts the seamless flow of data and threatens the network’s overall reliability;also,BHA strategically disrupts communication pathways by dropping data packets from legitimate nodes altogether.Recognizing the importance of this challenge,we have introduced a new solution called ad hoc On-Demand Distance Vector-Reputation-based mechanism Local Outlier Factor(AODV-RL).The significance of AODVRL lies in its unique approach:it verifies and confirms the trustworthiness of network components,providing robust protection against BHA.An additional safety layer is established by implementing the Local Outlier Factor(LOF),which detects and addresses abnormal network behaviors.Rigorous testing of our solution has revealed its remarkable ability to enhance communication in VANETs.Specifically,Our experimental results achieve message delivery ratios of up to 94.25%andminimal packet loss ratios of just 0.297%.Based on our experimental results,the proposedmechanismsignificantly improves VANET communication reliability and security.These results promise a more secure and dependable future for IoV,capable of transforming transportation safety and efficiency.

关键词： Black hole attack IoV vehicular ad hoc network AODV routing protocol

STUDY OF RADIO DEVICES ON 2.4GHZ ISM BAND IN PHYSICAL PHASE

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中国西部科技 2008年第34期7卷 5-8页

作者： Li Li(Department of Electrical and Computer Engineering illinois institute of technology Chicago,IL 60616) Department of Electrical and Computer Engineering illinois institute of technology Chicago IL60616

In the unlicensed 2.4GHz ISM band,there is not only IEEE 802.11 wireless systems being used,but also some other devices,such as residential microwave oven,Bluetooth devices,and cordless phone.All these devices that are not used for the data communications cause unintentional interference that will degrade the WI-FI system.In this paper,the transmission powers for common RF devices are measured and the SIR(signal-to-interference ratio)of different interferers to Wi-Fi is also studied.With this information,the effect of different interference on WI-FI signal can hence be quantified.Furthermore,the ability of the interference avoidance protocols,which is built into the AP,to address interference problems caused by that device is determined.

关键词：微波炉无塞绳交换机透射概率无线电通信