检索结果-内蒙古大学图书馆

A smoothed finite element method using second-order cone programming

COMPUTERS AND GEOTECHNICS 2020年 123卷 103547-103547页

作者： Meng, Jingjing Zhang, Xue Huang, Jinsong Tang, Hongxiang Mattsson, Hans Laue, Jan Lulea Univ Technol Dept Civil Environm & Nat Resources Engn Lulea Sweden Univ Liverpool Dept Civil Engn & Ind Design Liverpool Merseyside England Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian Peoples R China Univ Newcastle Prior Res Ctr Geotech Sci & Engn Discipline Civil Surveying & Environm Engn Callaghan NSW 2308 Australia

In this paper, a new approach abbreviated as SOCP-SFEM is developed for analysing geomechanical problems in elastoplasticity. The SOCP-SFEM combines a strain smoothing technique with the finite element method (FEM) in second-order cone programming (SOCP) and thereby inherits the advantages of both the smoothed finite element method (SFEM) and the SOCP-FEM. Specifically, the low-order mixed element can be used in the SOCP-SFEM without volumetric locking issues and the singularity associated with some typical constitutive models (e.g. the Mohr-Coulomb model and the Drucker-Prager model) is no longer a problem. In addition, the frictional and the cohesive-frictional interfaces can be implemented straightforward in the developed SOCP-SFEM owing to the adopted mixed variational principle and the smoothing technique. Furthermore, the multiple contact constraints, such as a cohesive interface with tension cut-off which is commonly used for analysing the bearing capacity of a pipeline buried in clays, can be simulated with little extra effort. To verify the correctness and robustness of the developed formulation for SOCP-SFEM, a series of benchmarks are considered where the simulation results are in good agreements with the analytical solutions and the reported numerical results.

关键词： Smoothed finite element method convex programming Strain smoothing technique Second-order cone programming Contact problems

来源：评论

学校读者我要写书评

暂无评论

Inferring electric vehicle charging patterns from smart meter data for impact studies

引用

ELECTRIC POWER SYSTEMS RESEARCH 2024年 235卷

作者： Li, Feng Campeau, Elodie Kocar, Ilhan Lesage-Landry, Antoine Polytech Montreal Dept Elect Engn GERAD Montreal PQ H3T 1J4 Canada Mila Montreal PQ H3T 1J4 Canada Hong Kong Polytech Univ Dept Elect & Elect Engn Hong Kong Peoples R China Eatons CYME Int T&D Brossard PQ J4Z 0N5 Canada

In this work, we propose a non-intrusive and training free method to detect behind-the-meter (BTM) electric vehicle (EV) charging events from the data measured by advanced metering infrastructure (AMI) such as smart meters. By leveraging the contextual information of EV charging, we formulate a mixed-integer convex quadratic program (MICQP) to detect EV charging events from customers' daily meter data. No labeled training data or hyperparameter tuning are required, and the MICQP can be efficiently solved. By collecting information about the start time, the charging duration, and the power level of each detected charging event, we infer customers' charging patterns in terms of probabilities of charging profiles through a data-driven approach using one year's meter data. In a numerical case study, we use the proposed approach to extract EV charging events from a test dataset of customers' meter data, and we demonstrate that similar detection accuracy is achieved as that of other learning-based approaches which use high-solution meter data. Finally, impacts of EV charging on the IEEE-8500 test feeder are presented in the case study by using the inferred charging patterns.

关键词： convex programming Data-driven Electric vehicle Smart meter Behind-the-meter Distribution networks

来源：评论

学校读者我要写书评

暂无评论

Certifiable relative pose estimation

引用

IMAGE AND VISION COMPUTING 2021年 109卷 104142-104142页

作者： Garcia-Salguero, Mercedes Briales, Jesus Gonzalez-Jimenez, Javier Univ Malaga Syst Engn & Automat Dept Machine Percept & Intelligent Robot MAPIR Grp Campus Teatinos Malaga 29071 Spain

In this paper we present the first fast optimality certifier for the non-minimal version of the Relative Pose prob-lem for calibrated cameras from epipolar constraints. The proposed certifier is based on Lagrangian duality and relies on a novel closed-form expression for dual points. We also leverage an efficient solver that performs local optimization on the manifold of the original problem's non-convex domain. The optimality of the solution is then checked via our novel fast certifier. The extensive conducted experiments demonstrate that, despite its simplicity, this certifiable solver performs excellently on synthetic data, repeatedly attaining the (certified a posteriori) optimal solution and shows a satisfactory performance on real data. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Relative pose Essential matrix Epipolar constraint convex programming Certifiable algorithm Linear Independence constraint qualification

来源：评论

学校读者我要写书评

暂无评论

A novel stepsize for gradient descent method

引用

OPERATIONS RESEARCH LETTERS 2024年 53卷

作者： Hoai, Pham Thi Vinh, Nguyen The Chung, Nguyen Phung Hai Hanoi Univ Sci & Technol Fac Math & Informat 1 Dai Co Viet Rd Hanoi Vietnam Univ Transport & Commun Dept Math Anal 3 Cau Giay St Hanoi Vietnam

We propose a novel adaptive stepsize for the gradient descent scheme to solve unconstrained nonlinear optimization problems. With the convex and smooth objective satisfying locally Lipschitz gradient we obtain the complexity O(1/k) of f (x(k)) - f* at most. By using the idea of the new stepsize, we propose k another new algorithm based on the projected gradient for solving a class of nonconvex optimization problems over a closed convex set. The computational experiments show the efficiency of the new method. (c) 2024 Elsevier B.V. All rights reserved.

关键词： convex programming Gradient descent method Nonlinear programming Projected gradient method Constrained optimization problem

来源：评论

学校读者我要写书评

暂无评论

Pattern synthesis with minimum mainlobe width via sparse optimization

引用

DIGITAL SIGNAL PROCESSING 2022年第0期128卷

作者： Peng, Weilai Gu, Tianyuan Zhuang, Yangjingzhi He, Zishu Han, Chunlin Univ Elect Sci & Technol China Sch Informat & Commun Engn Chengdu Peoples R China

This paper presents a pattern synthesis algorithm achieving minimum mainlobe width via sparse optimization. The problem of synthesizing a pattern with minimum mainlobe width is formulated as a sparse optimization problem with l0 norm by introducing a slack variable. To solve the sparse optimization problem, three existing relaxations for l0 norm are presented. Moreover, a novel log-sum-exp penalty function is proposed to replace l0 norm to be minimized in this paper, leading to a convex problem which can be solved directly and do not need to solve a sequence of sparse optimization problems compared with the iterative reweighted l1 norm. Both the focused beam pattern and shaped beam pattern for arbitrary arrays can be synthesized utilizing the proposed algorithm. Besides, the mainlobe width of pattern synthesized by the proposed algorithm is minimum. Simultaneously, it brings an extra advantage that it is no longer necessary to accurately determine the mainlobe region without synthesis performance degradation. Numerical examples are presented to verify the effectiveness and superiority of the proposed algorithm.(c) 2022 Elsevier Inc. All rights reserved.

关键词： Array pattern synthesis Mainlobe width Sparse optimization convex programming Log-sum-exp minimization

来源：评论

学校读者我要写书评

暂无评论

Extending battery lifetime of electric-hydraulic hybrid wheel loader through system parameter optimization

引用

ENERGY 2024年 313卷

作者： Lin, Zichang Wang, Feng Zhang, Haoxiang Xu, Bing Zhejiang Univ Sch Mech Engn State Key Lab Fluid Power Components & Mechatron S Hangzhou Peoples R China

Parallel electric hydraulic hybrid powertrain (PEHH) is a promising substitute for electric direct drive to extend battery lifetime. The convex programming (CP) based simultaneous optimization method has been adopted in electric hybrid system parameter optimization, but it is difficult to extend it for PEHH due to its non-convexity. In this paper, a combined exhaustive search - convex programming (ES-CP) system parameter optimization method is proposed to address the non-convexity of PEHH system parameter optimization problem. In this method, the PEHH system parameter optimization problem is modeled and reformulated in convex form and the convex part is decoupled from the optimization problem. The CP method is used for the convex part and the ES method is used for the remained non-convex part. The ES-CP method is applied to the PEHH powertrain to extend its battery lifetime. Optimization results show that the battery lifetime of the ES-CP optimized PEHH system is 6.8% longer than that of the non-optimized system. The computing time of ES-CP is 97 % lower than Latin hypercube sampling and 90 % lower than genetic algorithm methods.

关键词： System parameter optimization Wheel loader Battery lifetime Electric hydraulic hybrid system convex programming

来源：评论

学校读者我要写书评

暂无评论

Moment analysis of stochastic hybrid systems using semidefinite programming

引用

AUTOMATICA 2020年 112卷

作者： Ghusinga, Khem Raj Lamperski, Andrew Singh, Abhyudai Univ Delaware Dept Elect & Comp Engn Newark DE USA Univ Minnesota Dept Elect & Comp Engn Minneapolis MN USA

This paper proposes a method based on semidefinite programming for estimating moments of stochastic hybrid systems (SHSs). The class of SHSs considered herein consists of a finite number of discrete states and a continuous state whose dynamics as well as the reset maps and transition intensities are polynomial in the continuous state. For these SHSs, the dynamics of moments evolve according to a system of linear ordinary differential equations. However, it is generally not possible to exactly solve the system since time evolution of a specific moment may depend upon moments of order higher than it. Our methodology recasts an SHS with multiple discrete modes to a single-mode SHS with algebraic constraints. We then find lower and upper bounds on a moment of interest via a semidefinite program that includes linear constraints obtained from moment dynamics and those arising from the recasting process, along with semidefinite constraints coming from the non-negativity of moment matrices. We illustrate the methodology via an example of SHS. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Stochastic systems convex programming Jump process Optimization Polynomial models

来源：评论

学校读者我要写书评

暂无评论

Co-optimization method of speed planning and energy management for fuel cell vehicles through signalized intersections

引用

JOURNAL OF POWER SOURCES 2022年第0期518卷 230598-230598页

作者： Wei, Xiaodong Leng, Jianghao Sun, Chao Huo, Weiwei Ren, Qiang Sun, Fengchun Beijing Inst Technol Natl Engn Lab Elect Vehicles Beijing 100081 Peoples R China Hunan Univ State Key Lab Adv Design & Mfg Vehicle Body Changsha 410082 Hunan Peoples R China Beijing Informat Sci & Technol Univ Mech Elect Engn Sch Beijing 100192 Peoples R China Guangzhou Automobile Grp Co Ltd Automot Res & Dev Ctr Guangzhou 511434 Peoples R China

Network of vehicles technology can help vehicles obtain more traffic information during their journey. In this paper, a co-optimization method of speed planning and energy management is proposed for fuel cell vehicles (FCVs) while passing through multiple continuous signalized intersections. Based on the off-line dynamic programming (DP) algorithm and the signal phase and timing (SPaT), the constant-speed hydrogen consumption map and the weighted orientation graph of the FCV are established. Afterwards, a bi-level DP method is introduced to solve the speed planning problem online. In the meantime, a modified alternating direction method of multipliers (ADMM) algorithm, which includes a cyclic constraint inspection strategy to constrain the power change rate of fuel cell system (FCS), is used to solve the energy management problem. The simulation results demonstrate that the proposed method can generate an optimal speed reference trajectories for FCV through 4 and 8 signalized intersections in 3 s and 5 s respectively, which is practically implementable on real vehicles. Simulation results show that our proposed method is able to achieve similar fuel saving performance with off-line DP but a in real time framework, which is over 20% better than the improved intelligent driving model (IDM) with ADMM.

关键词： Fuel cell vehicles Speed planning Energy management convex programming Traffic signal

来源：评论

学校读者我要写书评

暂无评论

L1-gain control on positive impulsive system via a hybrid proportional plus integral algorithm

引用

IET CONTROL THEORY AND APPLICATIONS 2019年第7期13卷 898-904页

作者： Chen, Hao Zhan, Tao Huang, Qinzhen Southwest Minzu Univ Coll Elect & Informat Engn Chengdu 610041 Sichuan Peoples R China Univ Waterloo Dept Appl Math Waterloo ON N2L 3G1 Canada Shandong Univ Sch Math Jinan 250100 Shandong Peoples R China

In this study, the L1-gain control issues on positive system are investigated. A hybrid proportional impulsive with integral (PII) control scheme is proposed. This impulse-time-dependent control algorithm uses the proportional control action $K_p$Kp at impulse instants for stabilising, and applies the integral control strategy $K_{_I}$KI between impulse time intervals for improving the state convergence, respectively. The average impulsive interval approach and co-positive Lyapunov function method are employed to derive the sufficient conditions. Then L1-gain performance of the impulsive positive system can be guaranteed by solving the linear programming problem. In addition, iterative convex optimisation algorithm is presented for the design of PII control gain matrices. Numerical examples illustrate the expected results of this design.

关键词： Lyapunov methods matrix algebra gain control control system synthesis linear programming time-varying systems iterative methods convex programming stability impulse time intervals co-positive Lyapunov function method impulsive positive system iterative convex optimisation algorithm PII control gain matrices positive impulsive system hybrid proportional plus integral algorithm integral control scheme impulse-time-dependent control algorithm impulse instants impulsive interval approach integral control strategy o?'broken vertical bar(1) stability proportional control action K-p a"'(1)-gain control issues linear programming problem

来源：评论

学校读者我要写书评

暂无评论

Studies of Stochastic programming models using possibility and necessity measures for linear programming problems with fuzzy random variable coefficients

引用

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 2005年第1期88卷 68-75页

作者： Katagiri, H Sakawa, M Ishii, H Hiroshima Univ Grad Sch Engn Higashihiroshima 7398527 Japan Osaka Univ Grad Sch Informat Sci & Technol Suita Osaka 5650871 Japan

This paper considers the multi-objective linear programming problem and discusses the case in which the coefficients of the objective function are fuzzy random variables. First, the fuzzy goal is introduced into the objective function, considering the fuzzy decision of the human decision-maker. We consider a model in which the possibility or the necessity that the objective function value achieves the fuzzy goal is maximized on the basis of fuzzy programming or possibility programming. It is noted that the possibility or necessity fluctuates stochastically, and a decision-making process based on the stochastic programming model is proposed. After modifying the problem with constraint into an equivalent deterministic problem, the convex programming problem with a parameter is introduced. Then, an algorithm is proposed in which the optimal solution is derived, combining nonlinear programming and the bisection method. (C) 2004 Wiley Periodicals, Inc.

关键词： fuzzy random transform possibility measure necessity measure stochastic programming model convex programming

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：