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Full-Order Sliding mode Control for High-Order Nonlinear System Based on Extended State Observer

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Journal of Systems science & Complexity 2016年第4期29卷 978-990页

作者： CHEN Qiang TAO Liang NAN Yurong College of Information Engineering Zhejiang University of TechnologyHangzhou 310023China

In this paper, a full-order sliding mode control based on extended state observer(FSmC+ESO) is proposed for high-order nonlinear system with unknown system states and *** extended state observer(ESO) is employed to estimate both the unknown system states and uncertainties so that the restriction that the system states should be completely measurable is relaxed,and a full-order sliding mode controller is designed based on the ESO estimation to overcome the chattering problem existing in ordinary reduced-order sliding mode control. Simulation results show that the proposed method facilitates the practical application with respect to good tracking performance and chattering elimination.

关键词： Extended state observer full-order sliding mode control high-order nonlinear system

Profit Guided or Statistical Error Guided? A Study of Stock Index Forecasting Using Support Vector Regression

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Journal of Systems science & Complexity 2017年第6期30卷 1425-1442页

作者： HU Zhongyi BAO Yukun CHIONG Raymond XIONG Tao School of Information management Wuhan University School of management Huazhong University of Science and Technology School of Electrical Engineering and Computing The University of Newcastle College of Economics and management Huazhong Agricultural University

Stock index forecasting has been one of the most widely investigated topics in the field of financial forecasting. Related studies typically advocate for tuning the parameters of forecasting models by minimizing learning errors measured using statistical metrics such as the mean squared error or mean absolute percentage error. The authors argue that statistical metrics used to guide parameter tuning of forecasting models may not be meaningful, given the fact that the ultimate goal of forecasting is to facilitate investment decisions with expected profits in the future. The authors therefore introduce the Sharpe ratio into the process of model building and take it as the profit metric to guide parameter tuning rather than using the commonly adopted statistical metrics. The authors consider three widely used trading strategies, which include a na¨?ve strategy, a filter strategy and a dual moving average strategy, as investment scenarios. To verify the effectiveness of the proposed profit guided approach, the authors carry out simulation experiments using three global mainstream stock market indices. The results show that profit guided forecasting models are competitive, and in many cases produce significantly better performances than statistical error guided models. This implies thatprofit guided stock index forecasting is a worthwhile alternative over traditional stock index forecasting practices.

关键词： Financial market investment trading strategy parameter optimization stock index forecasting support vector regression

momentum-Dependent Symmetry Potential from Nuclear Collective Flows in Heavy Ion Collisions at Intermediate Energies

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Chinese Physics Letters 2015年第12期32卷 40-42页

作者：谢文杰冯兆庆 Department of Physics Yuncheng University Yuncheng 044000 Institute of modern Physics Chinese Academy of Sciences Lanzhou 730000

Within the isospin-dependent quantum molecular dynamics model, we investigate the nuclear collective flows produced in semi-central 197 Au＋197 Au collisions at intermediate energies. The neutron proton differential flows and difference of neutron proton collective flows are sensitive to the momentum-dependent symmetry potential. This sensitivity is less affected by both the isoscalar part of nuclear equation of state and in-medium nucleon- nucleon cross sections. moreover, this sensitivity becomes pronounced with increasing the rapidity cut.

关键词： momentum-Dependent Symmetry Potential from Nuclear Collective Flows in Heavy Ion Collisions at Intermediate Energies

Sliding mode Formation Control of Nonlinear multi-Agent Systems with Local Lipschitz Continuous Dynamics

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Journal of Systems science & Complexity 2019年第3期32卷 759-777页

作者： WANG Jinran LUO Xiaoyuan LI Xiaolei ZHU minggao GUAN Xinping School of Electrical Engineering Yanshan University Qinhuangdao 066004 China Branch of Light Industry Beijing Industry and Trade Technicians College Beijing 100079 China Institute of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Shanghai 200240 China

In this paper, the multi-agent formation problem of networked nonlinear multi-agent systems with local Lipschitz continuous dynamics under directed interaction topology, is investigated. Based on the nonlinear dynamics satisfying locally Lipschitz continuous conditions, three kinds of sliding mode controllers are proposed to solve the problem of multi-agent formation control. Using integral sliding mode controller in first-order system, formation shape is achieved within finite time. For second-order system, on the one hand, non-singular terminal sliding mode function is adopted to accomplish the system asymptotic convergence. Furthermore, super-twisting algorithm is proposed to make multi-agent achieve the desired formation within finite time. Lyapunov functions are applied in the whole paper to ensure the system stability. Numerical simulation examples are provided to demonstrate the effectiveness of the proposed sliding mode control methods.

关键词： Formation control nonlinear multi-agent system sliding mode super-twisting algorithm

mechanical Analysis and measurements of a multicomponent NbTi/Cu Superconducting magnets Structure for the Fully Superconducting Electron Cyclotron Resonance Ion Source

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Chinese Physics Letters 2016年第5期33卷 135-139页

作者：关明智胡强高配峰王省哲杨通军吴巍辛灿杰吴北民马力祯 Institute of modern Physics Chinese Academy of Sciences Key Laboratory of mechanics on Western Disaster and Environment College of Civil Engineering and MechanicsLanzhou University

A fully superconducting electron cyclotron resonance （ECR） ion source （SECRAL ID is currently being built in the Institute of modern Physics, Chinese Academy of sciences. Its key components are three superconducting solenoids （Nb-Ti/Cu） and six superconducting sextupoles （Nb-Ti/Cu）. Different from the conventional supercon- ducting ECR magnetic structure, the SEC17AL Ⅱ includes three superconducting solenoid coils＇ that are located inside the superconducting sextupoles. The SECRAL Ⅱ can significantly reduce the interaction forces between the sextupole and the solenoids, and the magnets can also be more compact in size. For this multi-component SECRAL Ⅱ generating its self field of -8 T and being often exposed to the high self field, the mechanical analysis has become the main issue to keep their stress at 〈200 mPa on coils. The analytical and experimental results in mechanics are presented in the SECRAL Ⅱ structure. To improve the accuracy and efficiency of analysis, according to the composite rule of micromechanics, the equivalent uniform windings are used to simulate the epoxy-impregnated Nb-Ti/Cu coils. In addition, using low temperature strain gauges and a wireless fast strain acquisition system, a fundamental experiment on the based on our analysis, the stresses and deformations optimized. strains developments of a sextupole is reported. Finally, for its assembly of each SECRAL Ⅱ coil will be further

关键词： of on is as NbTi mechanical Analysis and measurements of a multicomponent NbTi/Cu Superconducting magnets Structure for the Fully Superconducting Electron Cyclotron Resonance Ion Source in for Cu

Output Consensus for Heterogeneous Nonlinear multi-Agent Systems Based on T-S Fuzzy model

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Journal of Systems science & Complexity 2017年第5期30卷 1042-1060页

作者： LI Xiaolei LUO Xiaoyuan LI Shaobao GUAN Xinping School of Electrical Engineering Yanshan University Polytechnic School of Engineering New York University Institute of Electronic Information and Electrical EngineeringShanghai Jiao Tong University

In this paper, the output consensus problem of general heterogeneous nonlinear multi-agent systems subject to different disturbances is considered. A kind of Takagi-Sukeno fuzzy modeling method is used to describe the nonlinear agents' dynamics. Based on the model, a distributed fuzzy observer and controller are designed based on parallel distributed compensation scheme and internal reference models such that the heterogeneous nonlinear multi-agent systems can achieve output consensus. Then a necessary and sufficient condition is presented for the output consensus problem. And it is shown that the consensus trajectory of the global fuzzy model is determined by the network topology and the initial states of the internal reference models. Finally, some simulations are given to illustrate and verify the effectiveness of the proposed scheme.

关键词： Heterogeneous nonlinear multi-agent system internal reference model output consensus T-S fuzzy model.

Controllable Discrete Rogue Wave Solutions of the Ablowitz–Ladik Equation in Optics

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Communications in Theoretical Physics 2016年第7期65卷 29-34页

作者：闻小永 Department of mathematics School of Applied Science Beijing Information Science and Technology University Institute of Systems science Academy of Mathematics and Systems Science Chinese Academy of Sciences

With the aid of symbolic computation maple, the discrete Ablowitz–Ladik equation is studied via an algebra method, some new rational solutions with four arbitrary parameters are constructed. By analyzing related parameters, the discrete rogue wave solutions with alterable positions and amplitude for the focusing Ablowitz–Ladik equations are derived. Some properties are discussed by graphical analysis, which might be helpful for understanding physical phenomena in optics.

关键词： symbolic computation maple Ablowitz–Ladik equation rational solutions discrete rogue wave solutions

Enhancement of Breakdown Voltage in AlGaN/GaN High Electron mobility Transistors Using Double Buried p-Type Layers

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Chinese Physics Letters 2016年第6期33卷 121-124页

作者：罗俊赵胜雷林志宇张进成马晓华郝跃 Key Laboratory of Wide Band-Gap Semiconductor materials and Devices School of MicroelectronicsXidian University School of Advanced materials and Nanotechnology Xidian University

A novel A1GaN/GaN high electron mobility transistor （HEmT） with double buried p-type layers （DBPLs） in the GaN buffer layer and its mechanism are studied. The DBPL A1GaN/GaN HEmT is characterized by two equi-long p-type GaN layers which are buried in the GaN buffer layer under the source side. under the condition of high-voltage blocking state, two reverse p-n junctions introduced by the buried p-type layers will effectively modulate the surface and bulk electric fields. meanwhile, the buffer leakage is well suppressed in this structure and both lead to a high breakdown voltage. The simulations show that the breakdown voltage of the DBPL structure can reach above 2000 V from 467 V of the conventional structure with the same gate-drain length of 8μm.

关键词： AlGaN on is Enhancement of Breakdown Voltage in AlGaN/GaN High Electron mobility Transistors Using Double Buried p-Type Layers HEmT of in

Strain Avalanches in microsized Single Crystals:A Theoretical Study of the Relation between the Avalanche Size and Duration

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Chinese Physics Letters 2016年第9期33卷 100-103页

作者：张旭王志李倩尚福林 National Center for International Joint Research of micro-nano moulding Technology School of Mechanics and Engineering ScienceZhengzhou University State Key Laboratory for Strength and Vibration of mechanical Structures School of AerospaceXi'an Jiaotong University

Single crystal mieropillars deform via a sequence of discrete strain avalanches, observed as displacement jumps or stress drops. Here we develop a simple crystal plasticity model to provide a quantitative expression of the relation between avalanehe duration and avalanche size. It is found that the avalanche durations in scale with the averaged avalanche sizes only hold for those larger magnitudes. We show that the theoretical predictions are capable of capturing the essential aspeets of scaling behaviors from micro-compression tests.

关键词： of that in is