检索结果-内蒙古大学图书馆

Locally refined tetrahedral mesh generation based on advancing front technique with optimization and smoothing scheme

引用

COMMUNICATIONS IN NUMERICAL METHODS IN ENGINEERING 2004年第9期20卷 681-688页

作者： Choi, WY Son, IH Im, YT Korea Adv Inst Sci & Technol Dept Mech Engn Comp Aided Mat Proc Lab Taejon 305701 South Korea Digitalway Co Ltd Korea Design Ctr Seoungnam City 463828 Gyounggi Do South Korea

In this paper, a locally refined tetrahedral mesh generation algorithm based on advancing front technique using optimization scheme with a non-uniform trial height has been developed for three dimensional forming simulations to improve the quality of the local mesh system and computational efficiency. To generate locally refined surface elements, the refinement region was identified by checking the local affective strain rate and minimum interior angle of a surface element, respectively. In addition, a limiting value for the edge length of the tetrahedron was introduced to avoid generation of extremely small triangular surface elements. The developed scheme was applied for numerical simulations of indentation and spur gear and connecting rod forging. The computational results indicate that the currently developed algorithm was successful in generating better mesh system to finish numerical simulations with relatively shorter computation time compared to the previous scheme with a uniform trial height available in the literature. Copyright (C) 2004 John Wiley Sons, Ltd.

关键词： local refinement tetrahedral mesh generation advancing front technique optimization scheme

来源：评论

学校读者我要写书评

暂无评论

optimization of a deep foundation pit dewatering scheme in gypsum-bearing strata

引用

ENVIRONMENTAL EARTH SCIENCES 2024年第1期83卷 1-16页

作者： Ping, Shifei Wang, Fugang Wang, Donghui Li, Shengwei Yuan, Yilong Wu, Mingjie Pan, Huilin Cao, Yuqing Jilin Univ Key Lab Groundwater Resources & Environm Minist Educ 2519 Jiefang Rd Changchun 130012 Peoples R China Jilin Univ Jilin Prov Key Lab Water Resources & Environm Changchun 130012 Peoples R China China Geol Survey Chengdu Ctr Chengdu 610081 Peoples R China

The hydrodynamic changes and ground settlement induced by engineering dewatering have received much attention, and leakage between different aquifers is often neglected. Obviously, the leakage strength is crucial for the safety of underground engineering in soluble rock distribution areas. In this paper, we examined the Tianfu New Area in Chengdu, China, which contains a paste salt formation, based on numerical simulation techniques, characteristics of hydrodynamic field, leakage strength and ground settlement changes under different combinations of pumping well filter length and waterproof curtain depth were investigated. In the process of optimizing the dewatering scheme for this area, the leakage strength was innovatively included in the evaluation index. We found that as the depth of waterproof curtain increases, the trend of ground settlement and leakage strength caused by dewatering can be divided into a rapid decline phase and a gradual decline phase. However, the critical curtain depths of the two stages of ground settlement and leakage strength are different. The optimization scheme for dewatering engineering was determined under hydrodynamic, leakage strength, and ground settlement constraints. The filter length of the corresponding optimization scheme was 12 m, and the suitable depth of the waterproof curtain was 14-16 m. Our results provide an effective solution and method for optimizing the dewatering scheme in underground engineering projects with gypsum-bearing strata.

关键词： Dewatering of deep foundation pit Gypsum-bearing strata Leakage strength Ground settlement optimization scheme

来源：评论

学校读者我要写书评

暂无评论

Application of fractional shifted vieta-fibonacci polynomials in nonlinear reaction diffusion equation with variable order time-space fractional derivative

引用

PHYSICA SCRIPTA 2025年第2期100卷 025231-025231页

作者： Hassani, Hossein Avazzadeh, Zakieh Turan-Dincel, Arzu Katani, Roghayeh Anand Int Coll Engn Dept Math Jaipur 303012 India Anhui Univ Stony Brook Inst Hefei 230601 Anhui Peoples R China Univ South Africa Dept Math Sci Florida South Africa Yildiz Tech Univ Dept Math Engn TR-34220 Istanbul Turkiye Univ Yasuj Fac Sci Yasuj Iran

In this article, an accurate optimization algorithm based on new polynomials namely generalized shifted Vieta-Fibonacci polynomials (GSVFPs) is employed to solve the nonlinear variable order time-space fractional reaction diffusion equation (NVOTSFRDE). The algorithm combines GSVFPs, new variable order fractional operational matrices in the Caputo sense, and the Lagrange multipliers to achieve the optimal solution. First, the solution of the NVOTSFRDE is approximated as a series of GSVFPs with unknown coefficients and parameters. Then, the Lagrange multipliers method is adopted so that the NVOTSFRDE can be transformed into a class of nonlinear algebraic system of equations and we solve these equations using MATLAB and MAPLE software. Solving this system and substituting the coefficients and parameters into the approximation of the guessed functions, the solution of the NVOTSFRDE is obtained. The convergence analysis of the approach are discussed. The accuracy of the algorithm is verified through error analysis and mathematical examples. The accuracy of the new method is higher than that of the exciting method. The reconstruction results demonstrate that the proposed optimization algorithm is efficient for the NVOTSFRDE, and the algorithm is also convergent.

关键词： generalization of shifted vieta-fibonacci polynomials nonlinear variable order time-space fractional reaction diffusion equation optimization scheme lagrange multipliers variable order fractional derivative

来源：评论

学校读者我要写书评

暂无评论

Study on the mechanical mechanism and control optimization of station subsurface excavation by pile-beam-arch method

引用

SCIENTIFIC REPORTS 2025年第1期15卷 1-23页

作者： Liu, Nan Tong, Xiao Jiang, Yusheng Shan, Renliang Li, Ying Hebei Univ Engn Sch Civil Engn Handan 056000 Hebei Peoples R China Hebei Univ Engn Sch Earth Sci & Engn Handan 056000 Hebei Peoples R China China Univ Min & Technol Beijing Sch Mech & Civil Engn Beijing 100083 Peoples R China Liaoning Geol & Mineral Res Inst Co Ltd Shenyang 110032 Liaoning Peoples R China

This paper is based on the construction of the underground Pile-Beam-Arch station at Beitaipingzhuang Station of Beijing Metro Line 12. It employs finite element software for three-dimensional numerical modeling, faithfully reproducing the entire station construction process. The results indicate that the excavation of the pilot tunnel and the stage of the secondary lining buckle arch are the main causes of surface deformation. Additionally, the construction of the secondary lining buckle arch is the primary factor inducing deformation in the middle column and side pile. On this basis, the paper investigates the influence of four crucial factors: the stagger distance of the pilot tunnel excavation, the sequence of the secondary lining buckle arch, the excavation sequence of the lower soil, and the excavation depth on the stress and deformation characteristics of the stratum and the station structure. The results suggest that when the distance between adjacent pilot tunnel faces is 1.5 to 3 times the diameter of the pilot tunnel, it has the greatest influence on surface settlement. When the first side is followed by the middle, closely aligning the second lining with the initial support, and simultaneously installing buckle arches on both sides minimizes deformation of the stratum and station structure. During excavation of the lower soil in the station, reducing the single excavation depth and prioritizing excavation on both sides help control deformation of the vertical bearing structure. The optimal construction scheme is derived through multi-criteria optimization and implemented in the field. Field monitoring results are in good agreement with simulation outcomes, offering valuable reference for the construction of stations under similar geological conditions.

关键词： Pile-beam-arch Numerical simulation Deformation response optimization scheme On-site monitoring

来源：评论

学校读者我要写书评

暂无评论

optimization schemes for soft-switching PWM combined three-level converter

Optimization schemes for soft-switching PWM combined three-l...

引用

38th IEEE Power Electronic Specialists Conference (PESC 07)

作者： Liu, Fuxin Ruan, Xinbo Nanjing Univ Aeronaut & Astronaut Aero Power Sci Tech Ctr Nanjing 210016 Jiangsu Peoples R China

ISBN: (纸本)9781424406548

Soft-switching PWM combined three-level (TL) converters are very suitable for high input voltage with wide range applications due to the reduced voltage stress on power switches and reduced filter requirements. The converters include two transformers and have two operation modes, which provide possibilities to optimize the performance of the converters. This paper proposes some optimization strategies for the combined TL converters based on the control strategies and turns-ratios to achieve a better performance. Two prototype converters have been tested for the verification of the theoretical analysis.

关键词： optimization scheme zero-voltage-switching zero-current-switching combined three-level

来源：评论

学校读者我要写书评

暂无评论

The accuracy and efficiency of GA and PSO optimization schemes on estimating reaction kinetic parameters of biomass pyrolysis

引用

ENERGY 2019年 176卷 582-588页

作者： Ding, Yanming Zhang, Wenlong Yu, Lei Lu, Kaihua China Univ Geosci Fac Engn Wuhan 430074 Hubei Peoples R China Univ Sci & Technol China State Key Lab Fire Sci Hefei 230027 Anhui Peoples R China Zhengzhou Univ Sch Water Conservancy & Environm Zhengzhou 450001 Henan Peoples R China Zhengzhou Key Lab Water Resource & Environm Zhengzhou 450001 Henan Peoples R China

Reaction kinetic parameters estimation of biomass pyrolysis is a relatively difficult optimization problem due to the complexity of pyrolysis model. Two common heuristic algorithms, Genetic Algorithm (GA) and Particle Swarm optimization (PSO), are applied to estimate the kinetic parameters of three-component parallel reaction mechanism based on the thermogravimetric experiment in wide heating rates. The accuracy and efficiency of GA and PSO algorithms are compared with each other under the identical optimization conditions. The results indicate the better optimization abilities of PSO with the closer convergence solution to the global optimum and quicker convergence to the solution than GA based on the three-component parallel reaction mechanism of biomass pyrolysis. Especially, the improvement of best fitting value of PSO reaches up to 30% compared with that of GA. Furthermore, 14 estimated kinetic parameters of best fitting value are obtained and the mass loss rate predicted results including three separate components (hemicellulose, cellulose and lignin) are compared with experimental data. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Biomass pyrolysis Kinetic parameters optimization scheme GA PSO

来源：评论

学校读者我要写书评

暂无评论

A thermodynamic analysis of optimization schemes for a heat-power cogeneration system

引用

HIGH TEMPERATURES-HIGH PRESSURES 2020年第5-6期49卷 369-381页

作者： Ning, Zhe Ju, Wenping Hu, Bo Lv, Kai Zhou, Guiping Ma, Tingshan Wang, Yan Yang, Rongzu Xian Thermal Power Res Inst Co Ltd Xian Peoples R China State Grid Liaoning Elect Power Supply Co Ltd Shenyang Peoples R China

To overcome the strong thermoelectric coupling in a coal-fired combined heat and power plant (CCHPT), three optimization schemes are investigated. These include low-pressure turbine little steam operation (LLPEH), extracting steam from high pressure turbine (HP-LPEH), and integrating the LLPEH and HP-LPEH (HP-LLPEH). These are employed for enhancing the plant's heat and electricity supply flexibility using steam extracted between the intermediate- and low-pressure turbines to provide heat (LPEH). The thermodynamic and economic performance of the schemes when applied to a 330MW coal-fired combined heat and power plant were evaluated and compared. The comparison reveals the highest heat supply capacity, highest heat to electricity ratio, and lowest standard coal consumption for the HP-LLPEH scheme, while the LPEH exhibits the highest thermal efficiency.

关键词： optimization scheme heat-power cogeneration system heat supply thermoelectric coupling

来源：评论

学校读者我要写书评

暂无评论

Distributed formation control using robust asynchronous and broadcast-based optimization schemes

引用

IFAC-PapersOnLine 2018年第23期51卷 385-390页

作者： Modolo, Vinicio Varagnolo, Damiano Carli, Ruggero University of Padova Padova Italy Luleå University of Technology Luleå Sweden

We consider the problem of letting a network of mobile agents distributedly track and maintain a formation while using communication schemes that are asynchronous, broadcasts based, and prone to packet losses. To this purpose we revisit and modify an existing distributed optimization algorithm that corresponds to a distributed version of the Newton Raphson (NR) algorithm. The proposed scheme uses then robust asynchronous ratio consensus algorithms as building blocks, and employs opportune definitions for the local cost functions to achieve the desired coordination objective. In our algorithm, indeed, we code the position of the to-be-followed target as the minimum of a shared global cost, and capture the desired inter-robots behaviors through dedicated distances-based potential barriers. We then check the effectiveness of the strategy using field tests, and verify that the scheme achieves the desired goal of introducing robustness to changes in the agents positions due to unexpected disturbances. More precisely, if an agent breaks the formation, then the update mechanism embedded in our scheme make that agent move back to a meaningful position as soon as some packets are successfully received by the misplaced agent. © 2018

关键词： Mobile agents Cost functions Packet loss Target tracking Communication schemes Consensus algorithms Distributed formation control Distributed optimization Newton Raphson algorithm optimization scheme Potential barriers Update mechanisms

来源：评论

学校读者我要写书评

暂无评论

Overview of 2-Degree-of-Freedom Rotary-Linear Motors Focusing on Coupling Effect

引用

IEEE TRANSACTIONS ON MAGNETICS 2019年第4期55卷

作者： Xie, Lujia Si, Jikai Hu, Yihua Wang, Zheng Univ Liverpool Dept Elect Engn & Elect Liverpool L69 3BX Merseyside England Natl Tsing Hua Univ Dept Elect Engn Hsinchu 30013 Taiwan Zhengzhou Univ Dept Elect Engn Zhengzhou 450006 Henan Peoples R China Southeast Univ Sch Elect Engn Nanjing 211189 Jiangsu Peoples R China

The 2-degree-of-freedom (2DoF) rotary-linear (RL) motors are capable of implementing pure rotary motion, pure linear motion, or helical motion along the same axis, which have definite advantages of integrated structures, high material utilization, and fast response. Therefore, such motors have an extensive application prosperity ranging from robots, electric vessels, electric and hybrid vehicles, screwing machines, drilling machines, and intelligent machining systems. In this paper, an overview of 2DoF RL motors is presented, which can be divided into the motors with crossed RL magnetic field and those with independent RL magnetic fields. The development of various topologies and the corresponding coupling effect, optimization designs, and decoupling control algorithms are discussed and reviewed.

关键词： 2-degree-of-freedom (2-DoF) rotary-linear (RL) motor control algorithm coupling effect optimization scheme overview topology

来源：评论

学校读者我要写书评

暂无评论

Muntz-Legendre neural network construction for solving delay optimal control problems of fractional order with equality and inequality constraints

引用

SOFT COMPUTING 2020年第13期24卷 9575-9594页

作者： Kheyrinataj, Farzaneh Nazemi, Alireza Shahrood Univ Technol Fac Math Sci Shahrood Iran

In this paper, an artificial intelligence approach using neural networks is described to solve a class of delay optimal control problems of fractional order with equality and inequality constraints. In the proposed method, a functional link neural network based on the Muntz-Legendre polynomial is developed. The problem is first transformed into an equivalent problem with a fractional dynamical system without delay, using a Pade approximation. According to the Pontryagin's minimum principle for optimal control problems of fractional order and by constructing an error function, the authors then define an unconstrained minimization problem. The authors use trial solutions for the states, Lagrange multipliers and control functions where these trial solutions are constructed by a single-layer Muntz-Legendre neural network model. The authors then exploit an unconstrained optimization scheme for adjusting the network parameters (weights and bias) and to minimize the computed error function. Some numerical examples are given to illustrate the effectiveness of the proposed method.

关键词： Muntz-Legendre polynomial Functional link neural network Delay optimal control problems Fractional order Pade approximation Pontryagin minimum principle Error function optimization scheme

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：