检索结果-内蒙古大学图书馆

Temporal-spatial cross-correlation analysis of non-stationary near-surface wind speed time series

Journal of Central South University 2017年第3期24卷 692-698页

作者： ZENG Ming LI Jing-hai MENG Qing-hao ZHANG Xiao-nei Institute of Robotics and Autonomous Systems Tianjin Key Laboratory of Process Measurement and Control （School of Electrical Automation and Information Engineering Tianjin University） Tianjin 300072 China

Temporal-spatial cross-correlation analysis of non-stationary wind speed time series plays a crucial role in wind field reconstruction as well as in wind pattern ***,the near-surface wind speed time series recorded at different locations are studied using the detrended fluctuation analysis(DFA),and the corresponding scaling exponents are larger than *** indicates that all these wind speed time series have non-stationary ***,concerning this special feature( i.e.,non-stationarity)of wind signals,a cross-correlation analysis method,namely detrended cross-correlation analysis(DCCA) coefficient,is employed to evaluate the temporal-spatial cross-correlations between non-stationary time series of different anemometer ***,experiments on ten wind speed data synchronously collected by the ten anemometers with equidistant arrangement illustrate that the method of DCCA cross-correlation coefficient can accurately analyze full-scale temporal-spatial cross-correlation between non-stationary time series and also can easily identify the seasonal component,while three traditional cross-correlation techniques(i.e.,Pearson coefficient,cross-correlation function,and DCCA method) cannot give us these information directly.

关键词： temporal-spatial cross-correlation near-surface wind speed time series detrended cross-correlation analysis （DCCA） cross-correlation coefficient Pearson coefficient cross-correlation function

来源：评论

学校读者我要写书评

暂无评论

Analysis of Focusing Characteristics for Phased Array Used in Acousto-Electric Effect 29

Analysis of Focusing Characteristics for Phased Array Used i...

引用

第29届中国控制与决策会议

作者： Kai Zhu Yanbin Xu Feng Dong Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University

ISBN: (纸本)9781509046584

Acousto-Electrical Tomography(AET) based on the acousto-electric effect,is a promising new technique for a direct image formation method with enhanced ***-Electrical Tomography requires the focusing energy of ultrasonic focus to be greater in the security context and the focal point to be as small as *** with existing focusing techniques,phased array focusing technique is applied to Acousto-Electrical *** this study,the effects to the focus spot of ultrasound phased array are explored.A square phased array transducer is used to facilitate the study in the analysis and *** effects of two dimensional array transducer parameters are analyzed from two aspects:focus width and focal *** delay precision of hardware circuit design is analyzed theoretically in order to achieve the full coverage of the focal *** analysis results are verified by acoustic field simulation.

关键词： Acousto-Electrical Tomography Phased-Array Focusing Focus Spot Sound Field Simulation

来源：评论

学校读者我要写书评

暂无评论

Ultrasound Modulated Electrical Impedance Tomography by Contrast Libraries of Measurements Variation 29

Ultrasound Modulated Electrical Impedance Tomography by Cont...

引用

第29届中国控制与决策会议

作者： Shengnan Zhang Yanbin Xu Feng Dong Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University

ISBN: (纸本)9781509046584

Electrical impedance tomography(EIT) is a relatively new imaging technique developed in the recent ***,due to the ill-poseness of the inverse problem,spatial resolution of the reconstructed image is not ***-electric effect depicts that focused ultrasound alters the conductivity in the focal *** on the acousto-electric effect,ultrasound modulated electrical impedance tomography(UMEIT) is *** location information related to the original conductivity in the focused ultrasound area,contrast libraries of the measurements variation from background to object have been established,then the point-wise data of the boundary measurement are compared with the contrast libraries,and image of conductivity distribution is reconstructed with binarization directly without resorting to inverse *** the simulation results validate the effectiveness of the proposed method by the contrast libraries of the measurements *** method can reduce the effect of electrode location on sensitivity to improve the resolution,especially in the center of the imaging object,and avoid the ill-poseness of inverse problem.

关键词： Acousto-Electric Effect Ultrasound Modulated Electrical Impedance Tomography Contrast Libraries Binaryzation

来源：评论

学校读者我要写书评

暂无评论

Exponential convergence for distributed smooth optimization under the restricted secant inequality condition

arXiv

引用

arXiv 2019年

作者： Yi, Xinlei Zhang, Shengjun Yang, Tao Johansson, Karl H. Chai, Tianyou Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm100 44 Sweden Department of Electrical Engineering University of North Texas DentonTX76203 United States State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China

This paper considers the distributed smooth optimization problem in which the objective is to minimize a global cost function formed by a sum of local smooth cost functions, by using local information exchange. The standard assumption for proving exponential/linear convergence of first-order methods is the strong convexity of the cost functions, which does not hold for many practical applications. In this paper, we first show that the continuous-time distributed primal-dual gradient algorithm converges to one global minimizer exponentially under the assumption that the global cost function satisfies the restricted secant inequality condition. This condition is weaker than the strong convexity condition since it does not require convexity and the global minimizers are not necessary to be unique. We then show that the discrete-time distributed primal-dual algorithm constructed by using the Euler's approximation method converges to one global minimizer linearly under the same condition. The theoretical results are illustrated by numerical simulations. Copyright © 2019, The Authors. All rights reserved.

关键词： Continuous time systems

来源：评论

学校读者我要写书评

暂无评论

Linear convergence of first- And zeroth-order primal-dual algorithms for distributed nonconvex optimization

arXiv

引用

arXiv 2019年

作者： Yi, Xinlei Zhang, Shengjun Yang, Tao Chai, Tianyou Johansson, Karl H. Division of Decision and Control Systems School of Electrical Engineering and Computer Science Kth Royal Institute of Technology Digital Futures Stockholm100 44 Sweden Department of Electrical Engineering University of North Texas DentonTX76203 United States State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China

This paper considers the distributed nonconvex optimization problem of minimizing a global cost function formed by a sum of local cost functions by using local information *** first propose a distributed first-order primal-dual algorithm. We show that it converges sublinearly to a stationary point if each local cost function is smooth and linearly to a global optimum under an additional condition that the global cost function satisfies the Polyak-Lojasiewicz condition. This condition is weaker than strong convexity, which is a standard condition for proving linear convergence of distributed optimization algorithms, and the global minimizer is not necessarily unique. Motivated by the situations where the gradients are unavailable, we then propose a distributed zeroth-order algorithm, derived from the proposed distributed first-order algorithm by using a deterministic gradient estimator, and show that it has the same convergence properties as the proposed first-order algorithm under the same conditions. The theoretical results are illustrated by numerical simulations. Copyright © 2019, The Authors. All rights reserved.

关键词： Cost functions

来源：评论

学校读者我要写书评

暂无评论

Distributed bandit online convex optimization with time-varying coupled inequality constraints

arXiv

引用

arXiv 2019年

作者： Yi, Xinlei Li, Xiuxian Yang, Tao Xie, Lihua Johansson, Karl H. Chai, Tianyou Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm100 44 Sweden School of Electrical and Electronic Engineering Nanyang Technological University 50 Nanyang Avenue Singapore639798 Singapore State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China

This paper considers the problem of distributed bandit online convex optimization with time-varying coupled inequality constraints. This problem can be defined as a repeated game between a group of learners and an adversary. The learners attempt to minimize a sequence of global loss functions and at the same time satisfy a sequence of coupled constraint functions. The global loss and the coupled constraint functions are the sum of local convex loss and constraint functions, respectively, which are adaptively generated by the adversary. The local loss and constraint functions are revealed in a bandit manner, i.e., only the values of loss and constraint functions at sampled points are revealed to the learners, and the revealed function values are held privately by each learner. We consider two scenarios, one- and two-point bandit feedback, and propose two corresponding distributed bandit online algorithms used by the learners. We show that sublinear expected regret and constraint violation are achieved by these two algorithms, if the accumulated variation of the comparator sequence also grows sublinearly. In particular, we show that O(T θ1 ) expected static regret and O(T 7/4−θ1 ) constraint violation are achieved in the one-point bandit feedback setting, and O(T max{κ,1−κ}) expected static regret and O(T 1−κ/2) constraint violation in the two-point bandit feedback setting, where θ1 ∈ (3/4, 5/6] and κ ∈ (0, 1) are user-defined trade-off parameters. Finally, these theoretical results are illustrated by numerical simulations of a simple power grid example. Copyright © 2019, The Authors. All rights reserved.

关键词： Convex optimization

来源：评论

学校读者我要写书评

暂无评论

An Improved Output Feedback MPC scheme for Constrained Linear Systems

引用

IFAC-PapersOnLine 2017年第1期50卷 15506-15511页

作者： Subramanian, Sankaranarayanan Lucia, Sergio Engell, Sebastian Process Dynamics and Operations Group DortmundTU United States Otto-von-Guericke-University Magdeburg Laboratory for Systems Theory and Automatic Control Institute of Automation Engineering Germany

We propose an output feedback model predictive control (MPC) scheme that is independent of the estimation method employed. The proposed approach is non-conservative by design as the feedback information subject to estimation errors is explicitly considered in the predictions. The proposed scheme is robust to both the plant-model mismatch and the estimation error and avoids the unnecessary conservatism introduced by other existing output feedback MPC approaches in the literature. We achieve this by making use of all the available information at every time-step and formulate a control policy with the assumption that bounds for the estimation error are available at all times. We show that the proposed scheme is recursively feasible and demonstrate its advantages using a double-integrator example. © 2017

关键词： Feedback Errors Estimation Linear systems Model predictive control Predictive control systems Robust control Constrained linear systems Constrained systems Estimation methods Feed back information Multi stage Output feedback Plant model mismatches Robust model predictive control

来源：评论

学校读者我要写书评

暂无评论

A rigorous model for evaluating moving window soft sensors for industrial distillation processes

引用

Chemical engineering Transactions 2018年 69卷 487-492页

作者： Torgashov, Andrei Skogestad, Sigurd An, Dmitry Process Control Laboratory Institute of Automation and Control Process FEB RAS 5 Radio Str. Vladivostok Russia Department of Chemical Engineering Norwegian University of Science and Technology TrondheimNO-7491 Norway Gazpromneft-Omsk Refinery JSC 1 Pr. Gubkina Omsk644040 Russia

ISBN: (纸本)9788895608662

Traditionally, soft sensors are developed based on measurement data only, but here we consider a moving window (MW) soft sensor (SS) that uses data generated from a calibrated, rigorous model of the distillation columns of an FFC unit at Gazpromneft-Omsk Refinery. The contribution of the paper is that a procedure is developed for MW SS design that incorporates a priori knowledge, which is especially suitable when the training sample is small and contains measurement errors. In addition, we propose a continuous adaptation of all model parameters based on new data, instead of the usual procedure of only updating the bias. The accuracy of the predicted product quality is investigated by calculating the coefficient of determination (R2) and root mean squared error (RMSE) for the test sample. Several approaches were considered, and we found that a constrained optimization approach was superior. The constraints on the model parameters of SSs are derived from a calibrated, rigorous distillation unit model. The improved estimator quality resulted in the successful industrial application of advanced process control (APC) systems. © Copyright 2018, AIDIC Servizi S.r.l.

关键词： Distillation columns

来源：评论

学校读者我要写书评

暂无评论

Adaptive Optimization Deception Attack on Remote State Estimator of Aero-Engine 29

Adaptive Optimization Deception Attack on Remote State Estim...

引用

第29届中国控制与决策会议

作者： Xin Huang Jiuxiang Dong College of Information Science and Engineering Northeastern University State Key Laboratory of Synthetical Automation for Process Industries Center of Intelligent ControlNortheastern University

ISBN: (纸本)9781509046584

This paper studies the effect of the deception attacks on the remote state estimator equipped with the chisquared failure *** is assumed that the attacker can monitor and modify all the measurements.A novel adaptive optimization deception attack strategy is proposed,where using the current and previous sensor data,the attackers can ensure themselves to be undetected by the chi-squared monitor while yielding the largest estimation error covariance at the remote state *** the attacker's perspective,the attack is better than the existing other attacks to degrade the system ***,the simulation on the aero-engine model is provided to demonstrate theoretical results.

关键词： Cyber-Physical Systems Aero-Engine Remote State Estimation Cyber Attack Adaptive Optimization

来源：评论

学校读者我要写书评

暂无评论

A Tutorial Review on the Application of C/GMRES-based MPC Algorithm to Automotive Powertrain

A Tutorial Review on the Application of C/GMRES-based MPC Al...

引用

第37届中国控制会议

作者： Mingxin Kang Jiangyan Zhang State Key Laboratory of Synthetical Automation for Process Industries Northeastern University College of Mechanical and Electronic Engineering Dalian Minzu University State Key Laboratory of Automotive Simulation and Control Jilin University

Receding horizon control(RHC) gains much attention in industry owing to its merits that it is able to tackle explicitly the constrained and multi-variable optimization problem. However, a remarkable drawback of RHC is the heavy commutating load of the on-line solver algorithm, especially for nonlinear optimization problem. Hence, rare implementation can be found in engineering practice with a ‘fast‘ control system. To overcome this issue, some numerical solvers have been developed to improve the real-time performance of the optimization calculation, wherein the C/GMRES(Continuation/General Minimum Residual)algorithm gains bonus on its successful applications on fast control system. This tutorial paper proposes a brief introduction about C/GMRES algorithm, and then focuses on its applications to automotive powertrain control, including engine torque control, speed control, and energy management of hybrid electric vehicle(HEV). The control effects and real-time performance are validated by simulation and bench tests.

关键词： Real-time Optimization C/GMEES Automotive Powertrain Predictive control

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：