期刊文献+
共找到939篇文章
< 1 2 47 >
每页显示 20 50 100
Auxiliary Software for Defining the Parameters of the Structural Organization of a Complex System
1
作者 Branislav M. Savic 《Journal of Software Engineering and Applications》 2024年第2期109-128,共20页
The developed auxiliary software serves to simplify, standardize and facilitate the software loading of the structural organization of a complex technological system, as well as its further manipulation within the pro... The developed auxiliary software serves to simplify, standardize and facilitate the software loading of the structural organization of a complex technological system, as well as its further manipulation within the process of solving the considered technological system. Its help can be especially useful in the case of a complex structural organization of a technological system with a large number of different functional elements grouped into several technological subsystems. This paper presents the results of its application for a special complex technological system related to the reference steam block for the combined production of heat and electricity. 展开更多
关键词 complex System Structural Organization Auxiliary Software parameters
下载PDF
Influence analysis of complex crack geometric parameters on mechanical properties of soft rock
2
作者 Yang Zhao Xin He +3 位作者 Lishuai Jiang Zongke Wang Jianguo Ning Atsushi Sainoki 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第4期290-304,共15页
Soft rocks, such as coal, are afected by sedimentary efects, and the surrounding rock mass of underground coal mines is generally soft and rich in joints and cracks. A clear and deep understanding of the relationship ... Soft rocks, such as coal, are afected by sedimentary efects, and the surrounding rock mass of underground coal mines is generally soft and rich in joints and cracks. A clear and deep understanding of the relationship between crack geometric parameters and rock mechanics properties in cracked rock is greatly important to the design of engineering rock mass struc‑tures. In this study, computed tomography (CT) scanning was used to extract the internal crack network of coal specimens. Based on the crack size and dominant crack number, the parameters of crack area, volume, length, width, and angle were statistically analyzed by diferent sampling thresholds. In addition, the Pearson correlation coefcients between the crack parameters and uniaxial compression rock mechanics properties (uniaxial compressive strength UCS, elasticity modulus E) were calculated to quantitatively analyze the impact of each parameter. Furthermore, a method based on Pearson coefcients was used to grade the correlation between crack geometric parameters and rock mechanical properties to determine threshold values. The results indicated that the UCS and E of the specimens changed with the varied internal crack structures of the specimens, the crack parameters of area, volume, length and width all showed negative correlations with UCS and E, and the dominant crack played an important role both in weakening strength and stifness. The crack parameters of the angle are all positively correlated with the UCS and E. More crack statistics can signifcantly improve the correlation between the parameters of the crack angle and the rock mechanics properties, and the statistics of the geometric parameters of at least 16 cracks or the area larger than 5 mm2 are suggested for the analysis of complex cracked rock masses or physical reproduction using 3D printing. The results are validated and further analyzed with triaxial tests. The fndings of this study have important reference value for future research regarding the accurate and efcient selection of a few cracks with a signifcant infuence on the rock mechanical properties of surrounding rock mass structures in coal engineering. 展开更多
关键词 CT scanning complex crack Sampling threshold Soft rock Rock mechanics Crack geometric parameters
下载PDF
Hydrocarbon gas huff-n-puff optimization of multiple horizontal wells with complex fracture networks in the M unconventional reservoir
3
作者 Hao-Chuan Zhang Yong Tang +5 位作者 You-Wei He Yong Qin Jian-Hong Luo Yu Sun Ning Wang De-Qiang Wang 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1018-1031,共14页
The oil production of the multi-fractured horizontal wells(MFHWs) declines quickly in unconventional oil reservoirs due to the fast depletion of natural energy. Gas injection has been acknowledged as an effective meth... The oil production of the multi-fractured horizontal wells(MFHWs) declines quickly in unconventional oil reservoirs due to the fast depletion of natural energy. Gas injection has been acknowledged as an effective method to improve oil recovery factor from unconventional oil reservoirs. Hydrocarbon gas huff-n-puff becomes preferable when the CO_(2) source is limited. However, the impact of complex fracture networks and well interference on the EOR performance of multiple MFHWs is still unclear. The optimal gas huff-n-puff parameters are significant for enhancing oil recovery. This work aims to optimize the hydrocarbon gas injection and production parameters for multiple MFHWs with complex fracture networks in unconventional oil reservoirs. Firstly, the numerical model based on unstructured grids is developed to characterize the complex fracture networks and capture the dynamic fracture features.Secondly, the PVT phase behavior simulation was carried out to provide the fluid model for numerical simulation. Thirdly, the optimal parameters for hydrocarbon gas huff-n-puff were obtained. Finally, the dominant factors of hydrocarbon gas huff-n-puff under complex fracture networks are obtained by fuzzy mathematical method. Results reveal that the current pressure of hydrocarbon gas injection can achieve miscible displacement. The optimal injection and production parameters are obtained by single-factor analysis to analyze the effect of individual parameter. Gas injection time is the dominant factor of hydrocarbon gas huff-n-puff in unconventional oil reservoirs with complex fracture networks. This work can offer engineers guidance for hydrocarbon gas huff-n-puff of multiple MFHWs considering the complex fracture networks. 展开更多
关键词 Unconventional oil reservoir complex fracture network Hydrocarbon gas huff-n-puff parameter optimization Numerical simulation
下载PDF
Robust finite-time stabilization of unified chaotic complex systems with certain and uncertain parameters
4
作者 刘平 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第7期73-78,共6页
This paper deals with the finite-time stabilization of unified chaotic complex systems with known and unknown parameters. Based on the finite-time stability theory, nonlinear control laws are presented to achieve fini... This paper deals with the finite-time stabilization of unified chaotic complex systems with known and unknown parameters. Based on the finite-time stability theory, nonlinear control laws are presented to achieve finite-time chaos control of the determined and uncertain unified chaotic complex systems, respectively. The two controllers are simple, and one of the uncertain unified chaotic complex systems is robust. For the design of a finite-time controller on uncertain unified chaotic complex systems, only some of the unknown parameters need to be bounded. Simulation results for the chaotic complex Lorenz, Lu¨ and Chen systems are presented to validate the design and analysis. 展开更多
关键词 finite-time stability uncertain parameters unified chaotic complex systems
下载PDF
Investigations of the electron paramagnetic resonance parameters and the tetragonal local structure for (VCl_6)^(4-) coordination complex in MCl:V^(2+) (M=Na,K,Rb) systems
5
作者 祁林 邝小渝 +2 位作者 柴瑞鹏 段美玲 张彩霞 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第4期1586-1593,共8页
By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl... By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl:V2+ (M=Na, K, Rb) systems at 77K, 195 K and RT (room temperature 295 K or 302 K), respectively. The theoretical results indicate that there exists a compressed distortion in MCl:V2+ systems. Meanwhile, it finds that the structure parameters R1, R2 and |△R|( = R1 - R2) increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. △R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed. 展开更多
关键词 complete energy matrix EPR parameters (VCl6)4- coordination complex local structure
下载PDF
Effects of Complex Parameters on t→ch^0 in Supersymmetric QCD
6
作者 XINGLi-Rong MAWen-Gan ZHANGReu-You SUNYan-Bin HOUHong-Sheng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第2期241-246,共6页
We investigate the leading SUSY-QCD contributions to the branch ratio (BR) oft→ch~0 within the context of the minimal supersymmetric standard model (MSSM) with complex parameters,assuming more generally that there is... We investigate the leading SUSY-QCD contributions to the branch ratio (BR) oft→ch~0 within the context of the minimal supersymmetric standard model (MSSM) with complex parameters,assuming more generally that there is a misalignment between the squark and quark that leads to a flavor non-diagonal squark mass matrix.We introduce complex phases only in μ and At,namely φ_μ and φ_(Aq),for simplicity,and study the dependence of the BR of t→ch~0 on these phase parameters.Our calculations show that these CP-violation phases and the flavor mixing parameter λ influence the BR oft→ch~0 considerably,and the effect induced by φ_(At) is much larger than that by φ_μ and φ_(Ac(?)u.For different values of the complex parameters μ and A_t that are set in this paper,the BR of t -+ ch~ is in the range of 10~(-7)~10~(-6),depending mainly on the value of the trilinear coupling A_t. 展开更多
关键词 flavor changing rare decay SUSY-QCD minimal supersymmetric standard model complex parameters
下载PDF
The Complex Analysis Method of Numerical Identification of Parameters of Quasiideals Processes in Doubly-Connected Nonlinear-Layered Curvilinear Domains
7
作者 Olena Hladka Andriy Bomba 《Journal of Mathematics and System Science》 2014年第7期514-521,共8页
The method of numerical solving of nonlinear model problems of theory of a complex quasi-potential in doubly-connected nonlinear-layered curvilinear domains considering inverse influence function of flow on a conducti... The method of numerical solving of nonlinear model problems of theory of a complex quasi-potential in doubly-connected nonlinear-layered curvilinear domains considering inverse influence function of flow on a conductivity coefficient of medium was developed on the basis of synthesis of numerical methods of the quasi-conformal mappings and summary representations in conjunction with domain decomposition by method Schwartz. The proposed algorithm allows finding the potential of the quasiideals field, construction a motion grid (fluid-flow grid) simultaneously defining the flow lines that separate of sub-domains constancy of coefficient conductivity and identification the piecewise-constant values of coefficient conductivity, the local flows for the known measurements on boundary of domain. 展开更多
关键词 Quasi-conformal ('piecewise-conformal') mappings of numerical identification of parameters domain decomposition complex quasi-potential summary representations method method by method Schwartz nonlinear-layered medium.
下载PDF
Optimal Parameter and Uncertainty Estimation of a Land Surface Model: Sensitivity to Parameter Ranges and Model Complexities 被引量:2
8
作者 YoulongXIA Zong-LiangYANG +1 位作者 PaulL.STOFFA MrinalK.SEN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2005年第1期142-157,共16页
Most previous land-surface model calibration studies have defined globalranges for their parameters to search for optimal parameter sets. Little work has been conducted tostudy the impacts of realistic versus global r... Most previous land-surface model calibration studies have defined globalranges for their parameters to search for optimal parameter sets. Little work has been conducted tostudy the impacts of realistic versus global ranges as well as model complexities on the calibrationand uncertainty estimates. The primary purpose of this paper is to investigate these impacts byemploying Bayesian Stochastic Inversion (BSI) to the Chameleon Surface Model (CHASM). The CHASM wasdesigned to explore the general aspects of land-surface energy balance representation within acommon modeling framework that can be run from a simple energy balance formulation to a complexmosaic type structure. The BSI is an uncertainty estimation technique based on Bayes theorem,importance sampling, and very fast simulated annealing. The model forcing data and surface flux datawere collected at seven sites representing a wide range of climate and vegetation conditions. Foreach site, four experiments were performed with simple and complex CHASM formulations as well asrealistic and global parameter ranges. Twenty eight experiments were conducted and 50 000 parametersets were used for each run. The results show that the use of global and realistic ranges givessimilar simulations for both modes for most sites, but the global ranges tend to produce someunreasonable optimal parameter values. Comparison of simple and complex modes shows that the simplemode has more parameters with unreasonable optimal values. Use of parameter ranges and modelcomplexities have significant impacts on frequency distribution of parameters, marginal posteriorprobability density functions, and estimates of uncertainty of simulated sensible and latent heatfluxes. Comparison between model complexity and parameter ranges shows that the former has moresignificant impacts on parameter and uncertainty estimations. 展开更多
关键词 optimal parameters uncertainty estimation CHASM model bayesian stochasticinversion parameter ranges model complexities
下载PDF
Identification Schemes for Unmanned Excavator Arm Parameters 被引量:3
9
作者 Yahya H.Zweiri 《International Journal of Automation and computing》 EI 2008年第2期185-192,共8页
Parameter identification is a key requirement in the field of automated control of unmanned excavators (UEs). Furthermore, the UE operates in unstructured, often hazardous environments, and requires a robust paramet... Parameter identification is a key requirement in the field of automated control of unmanned excavators (UEs). Furthermore, the UE operates in unstructured, often hazardous environments, and requires a robust parameter identification scheme for field applications. This paper presents the results of a research study on parameter identification for UE. Three identification methods, the Newton-Raphson method, the generalized Newton method, and the least squares method are used and compared for prediction accuracy, robustness to noise and computational speed. The techniques are used to identify the link parameters (mass, inertia, and length) and friction coefficients of the full-scale UE. Using experimental data from a full-scale field UE, the values of link parameters and the friction coefficient are identified. Some of the identified parameters are compared with measured physical values. Furthermore, the joint torques and positions computed by the proposed model using the identified parameters are validated against measured data. The comparison shows that both the Newton-Raphson method and the generalized Newton method are better in terms of prediction accuracy. The Newton-Raphson method is computationally efficient and has potential for real time application, but the generalized Newton method is slightly more robust to measurement noise. The experimental data were obtained in collaboration with QinetiQ Ltd. 展开更多
关键词 parameters identification complex dynamic systems Newton-Raphson method generalized Newton method least squares method full-scale validation
下载PDF
Analytical study of the effect of the geometrical parameters during the interaction of regular wave-horizontal plate-current 被引量:1
10
作者 Smail Naasse Meriem Errifaiy Chakib Chahine 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2019年第5期10-20,共11页
The present work is an analytical study of the influence of geometrical parameters, such as length, thickness and immersion of the plate, on the reflection coefficient of a regular wave for an immersed horizontal plat... The present work is an analytical study of the influence of geometrical parameters, such as length, thickness and immersion of the plate, on the reflection coefficient of a regular wave for an immersed horizontal plate in the presence of a uniform current with the same direction as the propagation of the incident regular wave. This study was performed using the linearized potential theory with the evanescent modes while searching for complex roots to the dispersion equation that are neither pure real nor pure imaginary. The results show that the effects of the immersion and the relative length on the reflection coefficient of the plate are accentuated by the presence of the current, whereas the plate thickness practically does not have an effect if it is relatively small. 展开更多
关键词 current REGULAR wave EVANESCENT MODES reflection dispersion equation complex ROOTS GEOMETRICAL parameters
下载PDF
Control parameter optimal tuning method based on annealing-genetic algorithm for complex electromechanical system 被引量:1
11
作者 贺建军 喻寿益 钟掘 《Journal of Central South University of Technology》 2003年第4期359-363,共5页
A new searching algorithm named the annealing-genetic algorithm(AGA) was proposed by skillfully merging GA with SAA. It draws on merits of both GA and SAA ,and offsets their shortcomings.The difference from GA is that... A new searching algorithm named the annealing-genetic algorithm(AGA) was proposed by skillfully merging GA with SAA. It draws on merits of both GA and SAA ,and offsets their shortcomings.The difference from GA is that AGA takes objective function as adaptability function directly,so it cuts down some unnecessary time expense because of float-point calculation of function conversion.The difference from SAA is that AGA need not execute a very long Markov chain iteration at each point of temperature, so it speeds up the convergence of solution and makes no assumption on the search space,so it is simple and easy to be implemented.It can be applied to a wide class of problems.The optimizing principle and the implementing steps of AGA were expounded. The example of the parameter optimization of a typical complex electromechanical system named temper mill shows that AGA is effective and superior to the conventional GA and SAA.The control system of temper mill optimized by AGA has the optimal performance in the adjustable ranges of its parameters. 展开更多
关键词 GENETIC ALGORITHM SIMULATED ANNEALING ALGORITHM annealing-genetic ALGORITHM complex electro-mechanical system parametER tuning OPTIMAL control
下载PDF
Analysis of Channeling-Path Phenomena in a Complex Fault-Block Reservoir with Low Recovery Factor and High Water-Cut Ratio
12
作者 Qunyi Wang Xiaoli Ma +4 位作者 Yongbin Bi Haiyan He Xiao Gu Tongjing Liu Lekun Zhao 《Fluid Dynamics & Materials Processing》 EI 2023年第2期361-377,共17页
Current methods for the analysis of channeling-path phenomena in reservoirs cannot account for the influence of time and space on the actual seepage behavior.In the present study,this problem is addressed considering ... Current methods for the analysis of channeling-path phenomena in reservoirs cannot account for the influence of time and space on the actual seepage behavior.In the present study,this problem is addressed considering actual production data and dynamic characteristic parameters quantitatively determined in the near wellbore area by fitting the water-cut curve of the well.Starting from the dynamic relationship between injection and production data,the average permeability is determined and used to obtain a real-time quantitative characterization of the seepage behavior of the channeling-path in the far wellbore area.For the considered case study(Jidong oilfield),it is found that the seepage capacity of the channeling-path in the far wellbore area is far less(10 times smaller)than that of the channeling-path in the near wellbore area.The present study and the proposed model(combining near wellbore area and far wellbore area real-time data)have been implemented to support the definition of relevant adjustment measures to ultimately improve oil recovery. 展开更多
关键词 complex fault-block reservoirs channeling path quantitative identification characteristic parameters dynamic inversion
下载PDF
Detection of macular ganglion cell complex loss and correlation with choroidal thickness in chronic and recurrent central serous chorioretinopathy
13
作者 Yang-Chen Liu Bin Wu +1 位作者 Yan Wang Song Chen 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2023年第4期579-588,共10页
AIM:To investigate the association of ganglion cell complex thickness(GCCt),global loss volume percentage(GLV%),and focal loss volume percentage(FLV%)with structural and functional findings among patients with chronic... AIM:To investigate the association of ganglion cell complex thickness(GCCt),global loss volume percentage(GLV%),and focal loss volume percentage(FLV%)with structural and functional findings among patients with chronic central serous chorioretinopathy(CCSC)and recurrent central serous chorioretinopathy(RCSC)by optical coherence tomography(OCT).METHODS:Among 29 patients with monocular affected central serous chorioretinopathy(CSC),15 had CCSC,and 14 had RCSC.The GCCt,FLV%,GLV%,and subfoveal choroidal thickness(SFCT)and sublesional choroidal thickness(SLCT)values were determined using OCT,and the association of these characteristics with neural structure parameters,choroidal morphology,features and functional alterations were estimated for the CCSC and RCSC patients.RESULTS:In CCSC,the affected eyes had significantly lower GCCt values than the fellow eyes in the macular regions(all P<0.05),with the highest GCCt observed in the inferior area.A significant association was found between the GCCt in different regions and the change in best corrected visual acuity(BCVA;r=-0.696;-0.695;-0.694,P<0.05)in CCSC patients.A statistically significant moderate negative correlation indicated that long-term CCSC was associated with greater differences in the GCCt in different regions between affected and fellow eyes(r=-0.562;r=-0.556;r=0.525,P<0.05).Additionally,observation of thickened SFCT was associated with a worse FLV%(r=0.599;r=0.546,P<0.05)in both groups.Similarly,thickened SLCT was associated with FLV%in RCSC patients(r=0.544,P<0.05).CONCLUSION:The distribution and GCCt are associated with the duration and visual outcomes of CCSC,whereas there is no correlation among RCSC patients.FLV%may be instrumental in differentiating the various outer choroidal vessels(pachyvessels)in long-term CSC.These results suggest that neural structure parameters may aid in estimating and predicting the recovery of altered morphology and function in CCSC and RCSC patients. 展开更多
关键词 ganglion cell complex parameters choroidal thickness optical coherence tomography central serous chorioretinopathy
下载PDF
基于改进络合铁法的含硫化氢尾气处理工艺模拟与优化
14
作者 张瑞祥 谢若涵 +5 位作者 马晓珑 范峥 李长海 刘姝延 刘锋 胡杨 《石油与天然气化工》 CAS CSCD 北大核心 2024年第2期1-8,共8页
目的有效处理含硫尾气,确保装置“安、稳、长、满、优”运行。方法采用Aspen Plus V11软件基于Peng-Robinson热力学模型对改进络合铁装置的H_(2)S处理过程进行了全流程模拟,并根据Box-Behnken Design对其进行了响应面设计,得到了最佳H_(... 目的有效处理含硫尾气,确保装置“安、稳、长、满、优”运行。方法采用Aspen Plus V11软件基于Peng-Robinson热力学模型对改进络合铁装置的H_(2)S处理过程进行了全流程模拟,并根据Box-Behnken Design对其进行了响应面设计,得到了最佳H_(2)S脱除率及其对应的优化操作参数。结果此模拟流程能够较好地反映改进络合铁装置的实际运行情况,可以作为后续优化研究的基础模型。当循环溶液温度为47.2℃、循环溶液中Fe^(3+)质量分数为8.4100%、循环溶液体积流量为3.12 m^(3)/h、电解槽电压为0.64 V时,改进络合铁装置的H_(2)S脱除率高达99.999988%。此时,外排气中H_(2)S质量浓度为9.5 mg/m^(3),完全可以满足外排气中H_(2)S质量浓度不大于10 mg/m^(3)的约束条件;t检验结果表明,采用响应面法优化得到的预测值和验证值之间不存在显著差异,其准确度一致。结论该研究结果可为进一步提升含H_(2)S尾气处理水平提供准确、可靠的理论支撑和数据来源。 展开更多
关键词 含硫化氢尾气 改进络合铁法 热力学模型 流程模拟 响应面法 参数优化
下载PDF
一个单参数随机拟牛顿算法
15
作者 袁功林 莫中宇 罗珍华 《应用数学》 北大核心 2024年第3期706-717,共12页
本文设计一个单参数随机拟牛顿算法,证明该算法的收敛性并分析了复杂性,对非凸经验风险最小化问题进行数值实验,验证了算法的有效性和竞争性。
关键词 单参数 随机拟牛顿 收敛性 复杂性 非凸
下载PDF
考虑参数空间差异的复合式滑坡推力计算分析
16
作者 赵健 姚嘉昊 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第8期3189-3199,共11页
由于复合式滑坡不同滑区同一岩土计算参数数值存在差异性,导致滑坡推力大小判别难度加大。根据复合式滑坡破坏模式,概化构建滑坡地质模型,在此基础上建立滑坡物理力学模型,并对各区参数进行理论分析。根据滑坡失稳特征以及前人对复合式... 由于复合式滑坡不同滑区同一岩土计算参数数值存在差异性,导致滑坡推力大小判别难度加大。根据复合式滑坡破坏模式,概化构建滑坡地质模型,在此基础上建立滑坡物理力学模型,并对各区参数进行理论分析。根据滑坡失稳特征以及前人对复合式滑坡演化阶段划分的研究,将滑坡演化过程划分为前后裂隙开裂、前后滑带局部软化、前后滑带扩展、中部滑带软化、边坡整体失稳5个阶段,基于传递系数法和静力平衡条件构建不同演化阶段下的滑坡推力计算式。以汉巴南铁路某复合式滑坡为例,揭示了滑坡推力随水平距离增加的变化规律,并将计算结果与不考虑不同滑区同一岩土计算参数数值差异得出的计算结果进行对比分析。研究结果表明:1)在计算复合式滑坡推力时,考虑不同滑区同一岩土计算参数数值差异性的影响,其计算结果更加准确,规避因单一取值而导致计算推力不合理等问题。2)根据复合式滑坡不同演化阶段下的推力变化规律,在滑坡初期应以推移区和牵引区加固为主,当中部锁固区开始滑动,应以中部锁固区加固为主,同时也要加强推移区和牵引区的加固。3)在识别复合式滑坡演化阶段的基础上,根据此阶段构建的滑坡推力计算式得出推力空间变化规律,从而可提出较为合理的防治措施。 展开更多
关键词 复合式滑坡 演化过程 参数差异 传递系数法 推力计算
下载PDF
复杂曲面机器人磨抛技术研究现状与趋势展望综述
17
作者 张伟 余新阳 张伟中 《机电工程》 CAS 北大核心 2024年第7期1240-1250,共11页
在航空、能源、交通、军工等国家战略领域中,针对复杂曲面零件的自动化、高质量和高效率磨抛需求,对近年来国内外工业机器人磨抛加工关键技术及集成系统的研究和应用进展进行了综述。首先,从复杂曲面机器人磨抛机理及工艺优化、磨抛运... 在航空、能源、交通、军工等国家战略领域中,针对复杂曲面零件的自动化、高质量和高效率磨抛需求,对近年来国内外工业机器人磨抛加工关键技术及集成系统的研究和应用进展进行了综述。首先,从复杂曲面机器人磨抛机理及工艺优化、磨抛运动轨迹规划、磨削力控制等方面总结了复杂曲面机器人磨抛技术的研究成果;然后,介绍了国内外机器人磨抛集成系统应用现状;最后,分析了复杂曲面机器人磨抛技术的主要问题以及发展趋势,为该技术的发展提供了重要的指导和方向。研究结果表明:当前该技术存在的主要问题包括磨抛机理不够清晰,数学模型不够准确,复杂曲面机器人磨抛轨迹规划效率不高,磨抛力的控制仍不够精准等;另外,磨抛工艺参数优化、机器人力位混合控制、机器人高精度标定与误差补偿、基于数字孪生的机器人磨抛在线监控、机器人磨抛细分应用场景等方面的研究和实践将极大地推动机器人磨抛技术的发展和应用。 展开更多
关键词 发展趋势 抛磨机器人 复杂曲面零件 磨抛工艺参数优化 磨抛在线监控 高精度标定与误差补偿 磨削力控制 磨抛运动轨迹规划
下载PDF
参数未知的复混沌系统错位复修正函数投影同步
18
作者 杨玉佩 王聪 +2 位作者 张宏立 马萍 张绍华 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2024年第9期65-75,共11页
为解决参数未知的复混沌系统在复杂状态变量无法分离情况下的同步控制问题,提出了错位复修正函数投影同步(misalignment complex correction function projection synchronization,MCCFPS)控制方案。首先,设计一种自适应跟踪控制器,使... 为解决参数未知的复混沌系统在复杂状态变量无法分离情况下的同步控制问题,提出了错位复修正函数投影同步(misalignment complex correction function projection synchronization,MCCFPS)控制方案。首先,设计一种自适应跟踪控制器,使其能够适应任意有界复混沌系统之间的差异。该控制器通过动态控制强度和收敛因子增强自适应能力并调节收敛速度,通过Lyapunov理论证明该控制器的收敛性,从而为控制方案的可靠性提供理论支持。然后,对两个异构的复混沌系统进行动力学模型分析,计算并比较混沌系统和复混沌系统时间序列的模糊熵,验证复混沌系统的复杂度更高,从而突显其同步控制在保密通信应用中的优越性,并进一步设计其MCCFPS同步方案。最后,通过数值仿真验证MCCFPS方案的有效性。结果表明:该方案能够成功实现复混沌系统的同步控制,并具有良好的同步效果和控制性能。总体来说,相较于传统的混沌系统,研究引入复变量,并采用更复杂的MCCFPS同步控制方案,直接在复域中实现混沌同步,有效提高了系统的安全性。研究结果为复系统同步控制问题提供了新的思路和途径,具有重要的应用价值。 展开更多
关键词 复混沌系统 复变量 MCCFPS 参数辨识 模糊熵
下载PDF
玛湖凹陷风城组岩石力学参数自适应权重组合预测
19
作者 唐俊方 熊健 +3 位作者 刘向君 甘仁忠 罗德江 梁利喜 《石油地球物理勘探》 EI CSCD 北大核心 2024年第1期1-11,共11页
准噶尔盆地玛湖凹陷风城组岩性复杂,为准确预测其岩石力学参数,提出了一种自适应权重组合预测方法。首先分析、对比传统方法和不同机器学习算法(BP神经网络、XGBoost、支持向量机(SVM)、随机森林(RF)、卷积神经网络(CNN)、决策树(CART)... 准噶尔盆地玛湖凹陷风城组岩性复杂,为准确预测其岩石力学参数,提出了一种自适应权重组合预测方法。首先分析、对比传统方法和不同机器学习算法(BP神经网络、XGBoost、支持向量机(SVM)、随机森林(RF)、卷积神经网络(CNN)、决策树(CART)、长短时记忆神经(LSTM)网络等)的预测效果,传统方法难以准确预测岩石力学参数,而不同机器学习算法的预测效果不同,其中抗压强度、抗张强度和脆性指数预测的最优机器学习算法模型为SVM,弹性模量为BP,泊松比为RF,内聚力为XGBoost,内摩擦角和断裂韧性为LSTM网络;单一机器学习算法难以实现对多个岩石力学参数的同步准确预测。在此基础上,通过对不同岩石力学参数选取不同预测基模型,再根据基模型预测效果赋予权重并进行组合,以开展自适应权重组合预测。结果表明,该方法能够有效提升机器学习算法的预测精度和泛化性能,可实现复杂岩性地层多个岩石力学参数的同步准确预测。 展开更多
关键词 岩石力学参数 复杂岩性地层 机器学习 自适应组合预测
下载PDF
利用改进SCE算法的锂离子电池参数辨识
20
作者 许雅玲 陈志聪 +2 位作者 吴丽君 林培杰 程树英 《福州大学学报(自然科学版)》 CAS 北大核心 2024年第2期147-154,共8页
针对传统参数辨识方法中存在的易陷入局部最优和精度低问题,提出一种改进洗牌复杂演化算法(shuffed complex evolution, SCE).首先,提出描述电池的动态特性的二阶RC等效电路模型,并根据恒流放电工况测试数据集进行锂离子电池等效模型确... 针对传统参数辨识方法中存在的易陷入局部最优和精度低问题,提出一种改进洗牌复杂演化算法(shuffed complex evolution, SCE).首先,提出描述电池的动态特性的二阶RC等效电路模型,并根据恒流放电工况测试数据集进行锂离子电池等效模型确定待辨识参数.其次,将模型模拟端电压值与电池真实测试端电压均方根误差作为目标函数,并通过所提出的优化算法来寻找模型最优参数.最后,使用DST、 FUDS的锂离子电池动态工况数据集进行仿真验证,并与粒子群算法、灰狼算法、遗传算法进行比较.仿真结果表明,本方法在辨识精度方面具有优势,算法的参数辨识均方根误差(ERMS)平均值是0.016 6 V,相比较其他优化算法,分别降低了7.8%、 8.3%、 14.9%. 展开更多
关键词 锂离子电池 等效电路模型 参数辨识 洗牌复杂演化算法
下载PDF
上一页 1 2 47 下一页 到第
使用帮助 返回顶部