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Metamorphosis of discontinuity lines and rectification of magnetic flux avalanches in the presence of noncentrosymmetric pinning forces

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Physical Review B 2021年第22期103卷 224514-224514页

作者： M. Motta L. Burger Lu Jiang J. D. González Acosta Ž. L. Jelić F. Colauto W. A. Ortiz T. H. Johansen M. V. Milošević C. Cirillo C. Attanasio Cun Xue A. V. Silhanek B. Vanderheyden Departamento de Física Universidade Federal de São Carlos 13565-905 São Carlos São Paulo Brazil Montefiore Research Unit Department of Electrical Engineering and Computer Science Université de Liège 4000 Sart Tilman Belgium School of Aeronautics Northwestern Polytechnical University Xi'an 710072 China Facultad de Ingeniería Universidad del Magdalena Santa Marta Colombia Departement Fysica Universiteit Antwerpen Groenenborgerlaan 171 B-2020 Antwerpen Belgium Nokia Bell Labs Antwerp Belgium Department of Physics University of Oslo POB 1048 Blindern 0316 Oslo Norway CNR-SPIN c/o Università degli Studi di Salerno I-84084 Fisciano (Sa) Italy Dipartimento di Fisica “E.R. Caianiello” Università degli Studi di Salerno I-84084 Fisciano (Sa) Italy School of Mechanics Civil Engineering and Architecture and MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical University Xi'an 710072 China Experimental Physics of Nanostructured Materials Q-MAT CESAM Université de Liège B-4000 Sart Tilman Belgium

Considering a noncentrosymmetric pinning texture composed of a square array of triangular holes, the magnetic flux penetration and expulsion are investigated experimentally and theoretically. A direct visualization of the magnetic landscape obtained using a magneto-optical technique on a Nb film is complemented by a multiscale numerical modeling. This combined approach allows the magnetic flux dynamics to be identified from the single flux quantum limit up to the macroscopic electromagnetic response. Within the theoretical framework provided by time-dependent Ginzburg-Landau simulations, an estimation of the in-plane current anisotropy is obtained and its dependence with the radius of the curvature of hole vertices is addressed. These simulations show that current crowding plays an important role in channeling the flux motion, favoring hole-to-hole flux hopping rather than promoting interstitial flux displacement in between the holes. The resulting anisotropy of the critical current density gives rise to a distinct pattern of discontinuity lines for increasing and decreasing applied magnetic fields, in sharp contrast to the invariable patterns reported for centrosymmetric pinning potentials. This observation is partially accounted for by the rectification effect, as demonstrated by finite-element modeling. At low temperatures, where magnetic field penetration is dominated by thermomagnetic instabilities, highly directional magnetic flux avalanches with a fingerlike shape are observed to propagate along the easy axis of the pinning potential. This morphology is reproduced by numerical simulations. Our findings demonstrate that anisotropic pinning landscapes and, in particular, ratchet potentials produce subtle modifications to the critical state field profile that are reflected in the distribution of discontinuity lines.

关键词： Flux pinning Magneto-optical effect Monolayer films Superconductors Finite-element method Landau-Ginzburg theory

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Characterizing Coated Objects with Radar Identification system using Short-time Matrix Pencil Method

Characterizing Coated Objects with Radar Identification Syst...

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International Conference on Electrical engineering/Electronics, computer, Telecommunications and Information Technology, ECTI-CON

作者： Lakkhana Bannawat Santana Burintramart Akkarat Boonpoonga Department of Computer Engineering Faculty of Engineering Rajamangala University of Technology Rattanakosin Thailand Nakhon Pathom Defence Technology Institute (Public Organization) Ministry of Defence Nonthaburi Thailand Industrial Electric and Control System Research Center King Mongkut’s University of Technology North Bangkok Bangkok Thailand

This paper presents a radar target identification of a coated object. Based on the singularity expansion method, poles extracted from the received backscattering signal by using a short-time matrix pencil method were used as the object's signatures for identification. Simulation examples were illustrated in order to study on identification of a coated object. The antenna effect was taken into account and then mitigated by using a calibration technique. In simulations, the PEC sphere object was coated with dielectrics whose thickness was varied in order to investigate the behavior of extracted pole and the commencements of the late-time response of each object's layer. Simulation results showed that extracted poles obtained from the use of a short-time matrix pencil method can identify the PEC object coated with the dielectrics.

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A data-driven voltage control approach for grid-connected wind power plants

A data-driven voltage control approach for grid-connected wi...

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2018 IEEE Industry Applications Society Annual Meeting, IAS 2018

作者： Nasmus Sakib Khan Shabbir, M. Le, Anh Minh Liang, Xiaodong Khan, Nahidul Li, Weixing Memorial University of Newfoundland Department of Electrical and Computer Engineering St John'sNL Canada Newfoundland and Labrador Hydro System Operation and Planning Energy Control Center St John'sNL Canada Harbin Institute of Technology Department of Electrical Engineering Harbin Hilongjiang China

ISBN: (纸本)9781538645369

Due to increasing penetration of wind power plants (WPP), power grids are facing significant power quality challenges. To achieve stable and robust power system operation, reactive power plays a vital role. Reactive power needed to compensate voltage fluctuations at the point of interconnection (POI) of the WPP varies with a short circuit ratio (SCR). The reactive power capability of a WPP is also limited and largely depends on various operating conditions. In a physical system, it is difficult to find the correlation among critical parameters for voltage control. In this paper, a data-driven voltage control approach is proposed for a grid-connected WPP. Two regression models are developed through surface fitting using MATLAB curve fitting toolbox: one model based on simulation data is to determine the required reactive power for grid voltage compensation;another model based on field measurement data is to determine the WPP reactive power characteristics. The reactive power compensation device is capacitors in the study. Two controllers, a central WPP controller and a capacitor controller, are designed, their effectiveness is validated through several case and sensitivity studies. © 2018 IEEE

关键词： Reactive power

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A New FEM-based Brain Tissue Model for Neurosurgical Simulation Using the Optimization Implicit Euler Method

A New FEM-based Brain Tissue Model for Neurosurgical Simulat...

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第37届中国控制会议

作者： Wenguo Hou Peter X.Liu Minhua Zheng Shichao Liu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong University Department of System and Computer Engineering Carleton University

An accurate and computationally efficient model for the deformation of brain tissue is very important in virtual neurosurgical simulation. In this paper, we introduced a new Finite Element Method(FEM) model, which is based on optimization implicit Euler method, for brain tissue deformation. Specifically, both the anisotropic and viscoelastic properties of brain tissue are incorporated into the model, providing more realistic and accurate description of the mechanical features of brain tissue. In the meantime, the model is particularly suitable for GPU-based computing, making it possible to achieve real-time performance for neurosurgical simulation. Simulation results show that the deformation model exhibits the behaviors of anisotropy and viscoelasticity. The proposed model was implemented on a neurosurgical simulator and it showed that the deformation of brain tissue can be rendered with a relatively high degree of visual realism at a refreshment rate of 23 frames per second in a normal PC.

关键词： Brain Tissue Deformation Model Neurosurgical Simulation Optimization Implicit Euler

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Using the Model of a Functional Rationalizer of Consumer Behavior in Recommendation systems for Managing the Transport Activity of the Urban Population

Using the Model of a Functional Rationalizer of Consumer Beh...

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International Conference on Soft Computing and Measurements (SCM)

作者： Yaroslav A. Seliverstov Svytoslav A. Seliverstov Nikolay V. Podoprigora Alexey L. Starichenkov Roman S. Naryshkin Laboratory of Intelligent Transport Systems Solomenko Institute of Transport Problems of the Russian Academy of Sciences Institute of Computer Science and Technology Peter the Great St.Petersburg Polytechnic University St. Petersburg Russian Federation Department of Ground Transportation Technological Machines Saint Petersburg State University of Architecture and Civil Engineering St. Petersburg Russian Federation Department of Ship Control Systems Saint Petersburg Electrotechnical University “LETI” St. Petersburg Russian Federation Department of Programming Technology Saint Petersburg State University St. Petersburg Russian Federation

ISBN: (数字)9781728196923

ISBN: (纸本)9781728196930

An overview of existing urban software mobile applications of the transport and economic direction is given. A model of a functional rationalizer of consumer behavior is being built. The software model of the functional rationalizer of consumer behavior (SM FRCB) was developed for the first time. PMFRCB allows the user to expand the number of his preferred needs (occupations, activities) during the daily cycle through intelligent recommendations. Also, SM FRCB allows you to optimize needs (activities, activities) at the cost and rate of their use. The SM FRCB is made in Python_3 using the libraries matplotlib, collections, numpy, pyplot, mplot3d. The analysis of consumer behavior before and after using the functional rationalizer model is carried out. The graphical results of a structural analysis of the costs of old and new consumer behavior, analysis of consumer behavior within the boundaries of the theory of possibilities and the model of transport behavior of a resident before and after applying the functional rationalizer model are presented. The prospects of further improving the SM FRCB are considered.

关键词： Consumer behavior Mobile applications Sociology Statistics Logistics Analytical models Software

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Exploring the Mechanism of Residential Attractiveness in Compact Urban Areas – a Case Study of Hong Kong

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IOP Conference Series: Materials Science and engineering 2020年第1期829卷

作者： Yunxi Bai Jusheng Song Shanshan Wu S M Lo Gang Bai School of Architecture Harbin Institute of Technology HIT Campus of University Town of Shenzhen Shenzhen Guangdong China Department of Architecture Tongji University Siping Road Shanghai China Department of Architecture and Civil Engineering City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong College of Computer and Control Engineering Nankai University Weijin Road Tianjin China

Compact cities adopt high density, mixed land use and transit-oriented development (TOD). For sustainable development, compact development reduces the use of automobile and lessens the overdevelopment of land resources. For solving urban sprawl and housing shortage, more and more metropolises have adopted compact development. Academics, planners and policy makers mainly focused on evaluating the impacts of neighborhood attributes on housing prices and residential movements. Few have examined the relationships between residents' demand and residential attractiveness in compact cities. Therefore, this study develops Residential Attractiveness Evaluation (RAE) Model to evaluate the attractive degree of urban areas based on residents' demand in compact cities. Hong Kong is chosen as the study area which is a typical compact city. The results show that districts near the CBD and both sides of Victoria Harbor have highest residential attractiveness than other areas. Community planners and policy makers should consider residential attractiveness based on residents' demand in efforts to promote sustainable development. Residential attractiveness is the foundation of residential land use planning and policies. Planners in compact cities should adopt various planning strategies according to different residential attractiveness. Moreover, residential attractiveness is the benchmark of evaluating residents' satisfaction of new residential planning and policies.

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control of Nonlinear Constrained Ultra-Supercritical Boiler–Turbine Units Using Offset-Free Output-Feedback Stable MPC

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IFAC-PapersOnLine 2018年第28期51卷 155-160页

作者： Chen, Chen Pan, Lei Shen, Jiong Lee, Kwang Y. Zhang, Fan Sun, Li Wu, Xiao Zhang, Junli Xue, Wenchao Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education Southeast University Nanjing210096 China Department of Electrical and Computer Engineering Baylor University One Bear Place #97356 WacoTX76798-7356 United States State Key Lab of Power System Department of Energy and Power Engineering Tsinghua University Beijing100084 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China

It is extremely challenging to control ultra-supercritical boiler–turbine unit on account of its nonlinearity, coupling among multi-variables, hard input constraints, and unknown disturbances. An offset-free output-feedback stable model predictive control (MPC) (OFOF-SMPC) for nonlinear constrained ultra-supercritical boiler-turbine units is investigated. It is shown that the OFOF-SMPC is composed of a disturbance and state observer, a steady-state target calculator as well as a stable MPC, which can remove unknown disturbances from output channels and ensure the stability of the closed-loop system with input constraints. Simulation results demonstrate the effectiveness of the proposed algorithm. © 2018

关键词： Feedback

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A Gaussian Process Regression Approach for Fusion of Remote Sensing Images for Oil Spill Segmentation

A Gaussian Process Regression Approach for Fusion of Remote ...

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International Conference on Information Fusion

作者： Fodio S Longman Lyudmila Mihaylova Le Yang Department of Automatic Control and System Engineering University of Sheffield UK Department of Electrical and Computer Engineering University of Canterbury Chrischurch New Zealand

Synthetic Aperture Radar (SAR) satellite systems are very efficient in oil spill monitoring due to their capability to operate under all weather conditions. This paper presents a framework using Gaussian process (GP) to fuse SAR images of different modalities and to segment dark areas (assumed oil spill) for oil spill detection. A new covariance function; a product of an intrinsically sparse kernel and a Rational Quadratic Kernel (RQK) is used to model the prior of the estimated image allowing information to be transferred. The accuracy performance evaluation demonstrates that the proposed framework has 37% less RMSE per pixel and a compelling enhancement visually when compared with existing methods.

关键词： Oils Kernel Synthetic aperture radar Image resolution Gaussian processes Feature extraction Image segmentation

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A Management Model for Low Powered Wireless Personal Area Networks

A Management Model for Low Powered Wireless Personal Area Ne...

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IEEE International Symposium on World of Wireless Mobile and Multimedia Networks (WoWMoM)

作者： Yekta Türk Ali Akman Turk Telekom Mobile Access System Architecture Department Istanbul Turkey Computer Engineering Department Maltepe University Istanbul Turkey

ISBN: (纸本)9781538647264

Most of the researchers are investigating Internet of Things (IoT) to obtain information about our environment to control and act on it with the analysis of collected big data. An important topic with IoT is to manage the vast number of devices. In this demo, we demonstrate a management model in order to detect faults, analyze network and improve performance and connectivity in low powered mesh networks. The model can take actions when necessary and visualize those actions and the state of different managed objects. For building the proposed model, we have modified a well-known network management protocol to use for management data access and have performed fault and performance analysis in terms of values of counters collected from the interfaces. Our demonstrations indicate that the usage of the proposed method can perform well in limited bandwidth networks. At the same time, some security and device firmware related features are also added to the management system.

关键词： Protocols Performance evaluation Data visualization Bandwidth Databases Data models Security

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Technical note for "A Geodesic Approach for the control of Tethered Quadrotors"

arXiv

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arXiv 2019年

作者： Nguyen, Tam W. Nicotra, Marco M. Garone, Emanuele Department of Aerospace Engineering University of Michigan 1320 Beal Avenue Ann ArborMI48109 United States Department of Electrical Computer and Energy Engineering University of Colorado Boulder 425 UCB BoulderCO80309 United States Department of Control Engineering and System Analysis Université libre de Bruxelles Av. F.D. Roosevelt 50 C.P. 165/55 Belgium

This technical note focuses on the control of a quadrotor unmanned aerial vehicle (UAV) tethered to the ground. The control objective is to stabilize the UAV to the desired position while ensuring that the cable remains taut at all times. A cascade control scheme is proposed. The inner loop controls the attitude of the UAV. The outer loop gives the attitude reference to the inner loop, and is designed so that (i) the gravity force is compensated, (ii) the cable is taut at all times, and (iii) the trajectory of the UAV follows the geodesic path. To prove asymptotic stability, small gain arguments are used. The control scheme is augmented with a reference governor to enforce constraints. Copyright © 2019, The Authors. All rights reserved.

关键词： Unmanned aerial vehicles (UAV)

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