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Group decision-making method based on entropy and experts cluster analysis 被引量:12
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作者 Xuan Zhou Fengming Zhang Xiaobin Hui Kewu Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第3期468-472,共5页
According to the aggregation method of experts' evaluation information in group decision-making,the existing methods of determining experts' weights based on cluster analysis take into account the expert's preferen... According to the aggregation method of experts' evaluation information in group decision-making,the existing methods of determining experts' weights based on cluster analysis take into account the expert's preferences and the consistency of expert's collating vectors,but they lack of the measure of information similarity.So it may occur that although the collating vector is similar to the group consensus,information uncertainty is great of a certain expert.However,it is clustered to a larger group and given a high weight.For this,a new aggregation method based on entropy and cluster analysis in group decision-making process is provided,in which the collating vectors are classified with information similarity coefficient,and the experts' weights are determined according to the result of classification,the entropy of collating vectors and the judgment matrix consistency.Finally,a numerical example shows that the method is feasible and effective. 展开更多
关键词 group decision-making judgment matrix ENTROPY information similarity coefficient cluster analysis.
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Numerical Methods for a Class of Quadratic Matrix Equations
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作者 GUAN Jinrui WANG Zhixin SHAO Rongxia 《应用数学》 北大核心 2024年第4期962-970,共9页
Quadratic matrix equations arise in many elds of scienti c computing and engineering applications.In this paper,we consider a class of quadratic matrix equations.Under a certain condition,we rst prove the existence of... Quadratic matrix equations arise in many elds of scienti c computing and engineering applications.In this paper,we consider a class of quadratic matrix equations.Under a certain condition,we rst prove the existence of minimal nonnegative solution for this quadratic matrix equation,and then propose some numerical methods for solving it.Convergence analysis and numerical examples are given to verify the theories and the numerical methods of this paper. 展开更多
关键词 Quadratic matrix equation M-matrix Minimal nonnegative solution Newton method Bernoulli method
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Dynamic programming methodology for multi-criteria group decision-making under ordinal preferences 被引量:3
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作者 Wu Li Guanqi Guo +1 位作者 Chaoyuan Yue Yong Zhao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第6期975-980,共6页
A method of minimizing rankings inconsistency is proposed for a decision-making problem with rankings of alternatives given by multiple decision makers according to multiple criteria. For each criteria, at first, the ... A method of minimizing rankings inconsistency is proposed for a decision-making problem with rankings of alternatives given by multiple decision makers according to multiple criteria. For each criteria, at first, the total inconsistency between the rankings of all alternatives for the group and the ones for every decision maker is defined after the decision maker weights in respect to the criteria are considered. Similarly, the total inconsistency between their final rankings for the group and the ones under every criteria is determined after the criteria weights are taken into account. Then two nonlinear integer programming models minimizing respectively the two total inconsistencies above are developed and then transformed to two dynamic programming models to obtain separately the rankings of all alternatives for the group with respect to each criteria and their final rankings. A supplier selection case illustrated the proposed method, and some discussions on the results verified its effectiveness. This work develops a new measurement of ordinal preferences’ inconsistency in multi-criteria group decision-making (MCGDM) and extends the cook-seiford social selection function to MCGDM considering weights of criteria and decision makers and can obtain unique ranking result. 展开更多
关键词 multi-criteria group decision-making (MCGDM) ordinal preference minimum deviation method dynamic programming Cook-Seiford social selection function.
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Determination of initial cable force of cantilever casting concrete arch bridge using stress balance and influence matrix methods 被引量:10
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作者 TIAN Zhong-chu PENG Wen-ping +2 位作者 ZHANG Jian-ren JIANG Tian-yong DENG Yang 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第11期3140-3155,共16页
Cantilever casting concrete arch bridge using form traveller has a broad application prospect.However,it is difficult to obtain reasonable initial cable force in construction stage.In this study,stress balance and inf... Cantilever casting concrete arch bridge using form traveller has a broad application prospect.However,it is difficult to obtain reasonable initial cable force in construction stage.In this study,stress balance and influence matrix methods were developed to determine the initial cable force of cantilever casting concrete arch bridge.The stress balance equation and influence matrix of arch rib critical section were established,and the buckle cable force range was determined by the allowable stress of arch rib critical section.Then a group of buckle cable forces were selected and substituted into the stress balance equation,and the reasonable initial buckle cable force was determined through iteration.Based on the principle of force balance,the initial anchor cable force was determined.In an engineering application example,it is shown that the stress balance and influence matrix methods for the determination of initial cable force are feasible and reliable.The initial cable forces of arch rib segments only need to be adjusted once in the corresponding construction process,which improves the working efficiency and reduces the construction risk.It is found that the methods have great advantages for determining initial cable force in cantilever casting construction process of concrete arch bridge. 展开更多
关键词 concrete arch bridge cantilever casting initial cable force stress balance method influence matrix method
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Analysis on decision-making model of plan evaluation based on grey relation projection and combination weight algorithm 被引量:12
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作者 ZHANG Zhicai CHEN Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第4期789-796,共8页
In military service joint operations, when there are more operational forces, more multifarious materials are consumed, the support is more complex and fuzzy, the deployment of personnel is more rapid, and the support... In military service joint operations, when there are more operational forces, more multifarious materials are consumed, the support is more complex and fuzzy, the deployment of personnel is more rapid, and the support provided by wartime military material support powers can be more effective. When the principles,requirements, influencing factors and goals of military material support forces are deployed in wartime, an evaluation indicator system is established. Thus, a new combined empowerment method based on an analytic hierarchy process(AHP) is developed to calculate the subjective weights, and the rough entropy method is used to calculate the objective weights. Combination weights can be obtained by calculating the weight preference coefficient error, which is determined by combining the cooperative game method and the minimum deviation into objectives. This approach can determine the grey relation projection coefficient and synthesize the measure scheme superiority to finally optimize the deployment plan using the grey relation projection decision-making method. The results show that the method is feasible and effective;it can provide a more scientific and practical decision-making basis for the military material support power deployment in wartime. 展开更多
关键词 method for grey relation projection decision-making military supply power in war deployment plan optimization ana-lytic hierarchy process (AHP) rough entropy method
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Ranking environmental projects model based on multicriteria decision-making and the weight sensitivity analysis 被引量:5
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作者 Jiang Yan Tian Dagang Pan Yue 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2007年第3期534-539,共6页
With the fast growth of Chinese economic, more and more capital will be invested in environmental projects. How to select the environmental investment projects (alternatives) for obtaining the best environmental qua... With the fast growth of Chinese economic, more and more capital will be invested in environmental projects. How to select the environmental investment projects (alternatives) for obtaining the best environmental quality and economic benefits is an important problem for the decision makers. The purpose of this paper is to develop a decision-making model to rank a finite number of alternatives with several and sometimes conflicting criteria. A model for ranking the projects of municipal sewage treatment plants is proposed by using exports' information and the data of the real projects. And, the ranking result is given based on the PROMETHEE method. Furthermore, by means of the concept of the weight stability intervals (WSI), the sensitivity of the ranking results to the size of criteria values and the change of weights value of criteria are discussed. The result shows that some criteria, such as “proportion of benefit to project cost”, will influence the ranking result of alternatives very strong while others not. The influence are not only from the value of criterion but also from the changing the weight of criterion. So, some criteria such as “proportion of benefit to project cost” are key critera for ranking the projects. Decision makers must be cautious to them. 展开更多
关键词 multicriteria decision-making ranking environmental projects model PROMETHEE method sensitivity analysis weight stability intervals.
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Kohn-Sham Density Matrix and the Kernel Energy Method 被引量:1
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作者 POLKOSNIK Walter MASSA Lou 《物理化学学报》 SCIE CAS CSCD 北大核心 2018年第6期656-661,共6页
The kernel energy method(KEM) has been shown to provide fast and accurate molecular energy calculations for molecules at their equilibrium geometries.KEM breaks a molecule into smaller subsets,called kernels,for the p... The kernel energy method(KEM) has been shown to provide fast and accurate molecular energy calculations for molecules at their equilibrium geometries.KEM breaks a molecule into smaller subsets,called kernels,for the purposes of calculation.The results from the kernels are summed according to an expression characteristic of KEM to obtain the full molecule energy.A generalization of the kernel expansion to density matrices provides the full molecule density matrix and orbitals.In this study,the kernel expansion for the density matrix is examined in the context of density functional theory(DFT) Kohn-Sham(KS) calculations.A kernel expansion for the one-body density matrix analogous to the kernel expansion for energy is defined,and is then converted into a normalizedprojector by using the Clinton algorithm.Such normalized projectors are factorizable into linear combination of atomic orbitals(LCAO) matrices that deliver full-molecule Kohn-Sham molecular orbitals in the atomic orbital basis.Both straightforward KEM energies and energies from a normalized,idempotent density matrix obtained from a density matrix kernel expansion to which the Clinton algorithm has been applied are compared to reference energies obtained from calculations on the full system without any kernel expansion.Calculations were performed both for a simple proof-of-concept system consisting of three atoms in a linear configuration and for a water cluster consisting of twelve water molecules.In the case of the proof-of-concept system,calculations were performed using the STO-3 G and6-31 G(d,p) bases over a range of atomic separations,some very far from equilibrium.The water cluster was calculated in the 6-31 G(d,p) basis at an equilibrium geometry.The normalized projector density energies are more accurate than the straightforward KEM energy results in nearly all cases.In the case of the water cluster,the energy of the normalized projector is approximately four times more accurate than the straightforward KEM energy result.The KS density matrices of this study are applicable to quantum crystallography. 展开更多
关键词 Kohn SHAM density matrix KERNEL energy method N-REPRESENTABILITY QUANTUM CRYSTALLOGRAPHY Watercluster
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Vibration analysis of fluid- structure interaction in water hammer based on transfer matrix method 被引量:1
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作者 GAO Hui TANG Xuelin 《排灌机械工程学报》 EI CSCD 北大核心 2016年第6期518-524,共7页
In consideration of the problem that the effect of conduit structure on water hammer has been ignored in the classical theory,the Poisson coupling between the fluid and the pipeline was studied and a fourteen-equation... In consideration of the problem that the effect of conduit structure on water hammer has been ignored in the classical theory,the Poisson coupling between the fluid and the pipeline was studied and a fourteen-equation mathematical model of fluid-structure interaction(FSI)was developed.Then,the transfer matrix method(TMM)was used to calculate the modal frequency,modal shape and frequency response.The results were compared with that in experiment to verify the correctness of the TMM and the results show that the fluid-structure coupling has a greater impact on the modal frequencies than the modal shape.Finally,the influence on the response spectrum of different damping ratios was studied and the results show that the natural frequency under different damping ratios has changed little but there is a big difference for the pressure spectrum.With the decreasing of damping ratio,the damping of the system on frequency spectrum is more and more significant and the dispersion and dissipation is more and more apparent.Therefore the appropriate damping ratio should be selected to minimize the effects of the vibration of the FSI.The results provide references for the theory research of FSI in the transient process. 展开更多
关键词 water hammer fluid-structure interaction transfer matrix method vibration analysis
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A Vicious Script in HTML Detection Method Using Judgment Matrix Approach
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作者 李志勇 张昊 +1 位作者 陶然 杜华 《Defence Technology(防务技术)》 SCIE EI CAS 2009年第1期76-80,共5页
A vicious script detection method based on statistic is proposed by analyzing the vicious script in the hypertext markup language(HTML).We utilize the judgment matrix approach which is one of the subjective weighting ... A vicious script detection method based on statistic is proposed by analyzing the vicious script in the hypertext markup language(HTML).We utilize the judgment matrix approach which is one of the subjective weighting approaches to set the different weights for various statistic methods.Then we make use of the weighted geometric method to perfect the statistic results.Experimental results show the validity of this method. 展开更多
关键词 判断矩阵 HTML 脚本 恶性 检测 超文本标记语言 统计分析 加权方法
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On Eigen-Matrix Translation Method for Classification of Biological Data
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作者 JIANG Hao QIU Yushan +1 位作者 CHENG Xiaoqing CHING Waiki 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第5期1212-1230,共19页
Driven by the challenge of integrating large amount of experimental data, classification technique emerges as one of the major and popular tools in computational biology and bioinformatics research. Machine learning m... Driven by the challenge of integrating large amount of experimental data, classification technique emerges as one of the major and popular tools in computational biology and bioinformatics research. Machine learning methods, especially kernel methods with Support Vector Machines (SVMs) are very popular and effective tools. In the perspective of kernel matrix, a technique namely Eigen- matrix translation has been introduced for protein data classification. The Eigen-matrix translation strategy has a lot of nice properties which deserve more exploration. This paper investigates the major role of Eigen-matrix translation in classification. The authors propose that its importance lies in the dimension reduction of predictor attributes within the data set. This is very important when the dimension of features is huge. The authors show by numerical experiments on real biological data sets that the proposed framework is crucial and effective in improving classification accuracy. This can therefore serve as a novel perspective for future research in dimension reduction problems. 展开更多
关键词 CLASSIFICATION dimension reduction eigen-matrix translation glycan data kernel method(KM) support vector machine (SVM)
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模块化多电平矩阵换流器的等值阻抗模型解析分析 被引量:1
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作者 魏杰 何佳伟 +2 位作者 李斌 周博昊 戴魏 《电力自动化设备》 北大核心 2025年第1期147-155,共9页
模块化多电平矩阵换流器(M3C)的阻抗建模是柔性低频输电系统稳定性分析和故障特性分析的关键理论基础。介绍了M3C的拓扑结构、数学模型与控制策略。在此基础上,分析了计及M3C拓扑结构特点、dq坐标变换过程和双dq分解控制的扰动电流-桥... 模块化多电平矩阵换流器(M3C)的阻抗建模是柔性低频输电系统稳定性分析和故障特性分析的关键理论基础。介绍了M3C的拓扑结构、数学模型与控制策略。在此基础上,分析了计及M3C拓扑结构特点、dq坐标变换过程和双dq分解控制的扰动电流-桥臂电压-扰动电压传递响应特性,推导了M3C等值阻抗特性与频率的关系,建立了可用固定电阻与随频率变化电抗串联表示的M3C等值阻抗数学模型。在PSCAD/EMTDC仿真平台上利用扫频法对等值阻抗理论分析的准确性进行验证,并讨论了系统控制参数、运行功率、一次参数等不同因素对M3C阻抗频率特性的影响。 展开更多
关键词 模块化多电平矩阵换流器 双dq分解控制 控制响应 等值阻抗 扫频法
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考虑约束的CSC格式总体矩阵存储算法
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作者 董正方 王佳豪 +2 位作者 李运华 程纬 王君杰 《科学技术与工程》 北大核心 2025年第10期4265-4273,共9页
为了提高有限元分析效率,减少内存消耗,对总体矩阵的存储算法进行研究。将约束条件统一处理为单元层面的矩阵分块,后续以刚度矩阵为例,确定了约束条件下刚度矩阵非零元素分布规律,并提出了适用于二维、三维有限元刚度矩阵非零元素数量... 为了提高有限元分析效率,减少内存消耗,对总体矩阵的存储算法进行研究。将约束条件统一处理为单元层面的矩阵分块,后续以刚度矩阵为例,确定了约束条件下刚度矩阵非零元素分布规律,并提出了适用于二维、三维有限元刚度矩阵非零元素数量计算方法及相应计算公式,同时检验了正确性;推导了一维等带宽存储与原始方阵地址对应关系,并将其作为辅助数组应用于CSC格式总体矩阵集成过程中,提高了总体矩阵组集效率,避免了节点编号优化难题。最后,以北京市房山线长稻区间四跨单线梁桥验证所提出算法的正确性与实用性,结果表明:该算法分析时总体矩阵组集时间减少30%、存储空间节省68%以上、保证了计算精度的同时线性方程组计算效率提升超过71%。 展开更多
关键词 有限单元法 刚度矩阵 非零元素 压缩存储 CHOLESKY分解
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一种适用于嵌入式导电薄层的高阶电磁波混合时域有限差分-时程精细积分法
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作者 马亮 马西奎 +2 位作者 迟明珺 向汝 朱晓杰 《电工技术学报》 北大核心 2025年第5期1333-1343,共11页
应用单一时域数值方法,在面对嵌入式导电薄层一类多尺度问题时,都面临着建模极为困难的挑战。该文提出了一种基于时域有限差分(FDTD)法和高阶时程精细积分(PITD)法的电磁波混合数值方法。该方法对导电薄层外部进行粗网格剖分并应用FDTD... 应用单一时域数值方法,在面对嵌入式导电薄层一类多尺度问题时,都面临着建模极为困难的挑战。该文提出了一种基于时域有限差分(FDTD)法和高阶时程精细积分(PITD)法的电磁波混合数值方法。该方法对导电薄层外部进行粗网格剖分并应用FDTD法,而对薄层内部进行一维细网格剖分并应用四阶PITD法,以实现不同网格尺度的同步时间推进。为了实现粗细网格之间的信息交换,在PITD域中引入过渡区域并应用二阶PITD法,通过等效本构参数来更新交界面处的切向电场。分析了该混合算法的数值稳定性和数值反射,并通过典型数值算例验证了所提方法的有效性和准确性。 展开更多
关键词 时域有限差分法 四阶时程精细积分法 亚网格技术 矩阵指数
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非平稳异常噪声条件下的扩展目标跟踪方法
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作者 陈辉 张欣雨 +2 位作者 连峰 韩崇昭 张光华 《电子与信息学报》 北大核心 2025年第3期803-813,共11页
针对非平稳异常噪声环境下扩展目标跟踪问题,该文提出一种基于高斯-学生t混合(GSTM)扩展目标跟踪方法。首先,将过程噪声和量测噪声建模为GSTM分布,以表征非平稳厚尾噪声,并通过引入伯努利随机变量,将目标的运动状态和量测似然函数建模... 针对非平稳异常噪声环境下扩展目标跟踪问题,该文提出一种基于高斯-学生t混合(GSTM)扩展目标跟踪方法。首先,将过程噪声和量测噪声建模为GSTM分布,以表征非平稳厚尾噪声,并通过引入伯努利随机变量,将目标的运动状态和量测似然函数建模为分层高斯形式。其次,在随机矩阵(RMM)滤波框架下,使用变分贝叶斯方法详细推导了非平稳厚尾噪声下的GSTM扩展目标跟踪算法。该算法通过建模高斯噪声与厚尾噪声之间的非平稳过程,精确表征噪声特性,从而在非平稳异常噪声环境下稳健捕捉扩展目标的质心位置和轮廓形态。最后,构建非平稳异常噪声环境下的扩展目标跟踪仿真实验,并通过高斯-瓦瑟斯坦距离对实验结果进行效果评估,验证了所提出算法的合理性。此外,真实场景实验结果进一步证明了该算法在实际应用中的有效性和鲁棒性。 展开更多
关键词 扩展目标跟踪 随机矩阵 高斯-学生t混合分布 变分贝叶斯方法
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激光加工机器人复杂相贯线切割轨迹规划方法
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作者 李莎 高威 +1 位作者 陈磊 梁晓莉 《激光杂志》 北大核心 2025年第6期226-231,共6页
激光加工机器人在执行复杂相贯线切割任务时,由于无法对大量三维空间数据进行处理,导致其容易出现轨迹规划精度不佳的问题。为解决这一问题,本研究提出了一种激光加工机器人复杂相贯线切割轨迹规划方法。首先,构建相贯线数学模型,切割... 激光加工机器人在执行复杂相贯线切割任务时,由于无法对大量三维空间数据进行处理,导致其容易出现轨迹规划精度不佳的问题。为解决这一问题,本研究提出了一种激光加工机器人复杂相贯线切割轨迹规划方法。首先,构建相贯线数学模型,切割过程中相贯线的具体形态;然后,运用平面转换结合插补递推技术,对相贯线的切割误差实施补偿处理,确保切割的精确性;最后,以经过补偿处理的相贯线作为切割轨迹,利用矩阵变换方法完成激光加工机器人的切割轨迹规划。实验结果表明,所提方法的激光加工机器人切割轨迹规划效果更好、精度更高,具有更大的应用价值。 展开更多
关键词 相贯线 激光加工机器人 矩阵变换 插补递推方法 轨迹规划
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某丙烷脱氢装置大型管道高频振动特性分析
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作者 贺佳 梁浩华 +3 位作者 张国华 杨玉强 胡美妃 陈政清 《振动与冲击》 北大核心 2025年第4期144-150,共7页
大型石化管道服役期间,受复杂工作环境影响,可能发生高频剧烈振动,影响结构正常使用,并存在较大的安全隐患,因此,很有必要对此类振动现象开展相关研究。以某丙烷脱氢装置的大型管道为对象,基于现场实测数据,分析了管道振动特性,并利用... 大型石化管道服役期间,受复杂工作环境影响,可能发生高频剧烈振动,影响结构正常使用,并存在较大的安全隐患,因此,很有必要对此类振动现象开展相关研究。以某丙烷脱氢装置的大型管道为对象,基于现场实测数据,分析了管道振动特性,并利用传递矩阵法,获取了管道内部不同工况下的气柱固有频率。研究发现:管道振动的加速度幅值大、位移幅值小,振动频率较高,且卓越频率之间存在明显的倍数关系,即倍频现象,如26 Hz和52 Hz;气柱固有频率与管道固有频率接近,结合压缩机的激励频率,引发了管道的共振现象。该研究采用的方法简便高效,可用于分析丙烷脱氢装置大型管道的振动特性,探求管道振动的原因,并为类似管道的性能评估和减振方案设计提供参考依据。 展开更多
关键词 管道振动 倍频现象 气柱固有频率 传递矩阵法
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移动随机载荷下波纹夹芯板的非平稳响应特性分析
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作者 李博 邵东 +1 位作者 曹渊 梁伟阁 《兵工学报》 北大核心 2025年第7期188-198,共11页
为研究波纹夹芯板在移动随机载荷作用下引起的非平稳振动问题,建立了一个通用的动力学解析模型。利用简化一阶剪切变形理论和Hamilton原理推导得到了单个胞元的控制微分方程,基于回传射线矩阵法和虚拟激励法,引入了递推技术有效的模拟... 为研究波纹夹芯板在移动随机载荷作用下引起的非平稳振动问题,建立了一个通用的动力学解析模型。利用简化一阶剪切变形理论和Hamilton原理推导得到了单个胞元的控制微分方程,基于回传射线矩阵法和虚拟激励法,引入了递推技术有效的模拟了整个结构在移动随机载荷作用下的全域响应。通过将负载的连续移动过程划分为3个阶段,提出了针对于移动随机载荷的统一加载机制,并通过有限元仿真软件验证了计算模型的精度。研究结果表明:通过调节波纹夹芯板的厚度和倾角可以有效拓宽结构的Bragg带隙;低速移动随机载荷在作用时间内会引起更多的振动行为。研究结果为波纹夹芯板在复杂载荷条件下的设计和优化提供了理论支持,并为航空航天和海洋工程等领域中相关装备的研制提供参考。 展开更多
关键词 波纹夹芯 模态阻尼 回传射线矩阵法 移动随机载荷 非平稳响应
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一种求解低秩矩阵补全的惯性加速交替方向法
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作者 闫喜红 唐晓妮 《运筹学学报(中英文)》 北大核心 2025年第1期172-184,共13页
交替方向法作为求解矩阵补全问题的经典方法之一,具有能够将一个极小化问题分解成多个规模更小、更容易求解的子问题的优势,近年来在图像处理和数据分析等领域备受青睐。本文采用交替方向法的框架,结合惯性策略,提出了一种求解矩阵补全... 交替方向法作为求解矩阵补全问题的经典方法之一,具有能够将一个极小化问题分解成多个规模更小、更容易求解的子问题的优势,近年来在图像处理和数据分析等领域备受青睐。本文采用交替方向法的框架,结合惯性策略,提出了一种求解矩阵补全问题的惯性加速交替方向法。新算法在每步迭代中,对于其中一部分变量利用交替方向法的前两次迭代点外推得到新一步的迭代点,从而提高计算效率。本文在合理的假设条件下,证明了新算法的收敛性。最后,通过随机矩阵补全的数值实验及图像修复的实例验证了新算法的有效性和可行性。 展开更多
关键词 矩阵补全问题 交替方向法 惯性加速
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基于结构参数分析的Gyroid换热器性能
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作者 杨晓军 张雪丽 李沛燃 《北京航空航天大学学报》 北大核心 2025年第4期1195-1204,共10页
为研究三重周期极小曲面(TPMS)在空气-燃油换热器中的流动换热特性,分析结构参数对换热器性能的影响。采用田口方法,针对壁厚、晶格大小和偏移尺寸3个结构参数,对努塞尔数和摩擦系数进行综合评估,并与参考的螺旋套管(TTHC)换热器性能进... 为研究三重周期极小曲面(TPMS)在空气-燃油换热器中的流动换热特性,分析结构参数对换热器性能的影响。采用田口方法,针对壁厚、晶格大小和偏移尺寸3个结构参数,对努塞尔数和摩擦系数进行综合评估,并与参考的螺旋套管(TTHC)换热器性能进行对比。研究得出各个结构参数影响Gyroid换热器努塞尔数和摩擦系数方面的主次顺序,并利用矩阵分析法,确定了最优方案。结果表明:对于热侧出口温度,TTHC换热器比参考的Gyroid换热器最高降低13.13 K;对于压降,TTHC换热器比参考的Gyroid换热器降低3.02 kPa;对于性能评估系数,热侧通道最高为14.72,冷侧通道最高为0.78。 展开更多
关键词 Gyroid换热器 螺旋套管换热器 田口方法 结构参数 矩阵分析法
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基于超对偶数微分的无约束应力更新算法
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作者 路德春 石安毓 +1 位作者 周鑫 杜修力 《岩土工程学报》 北大核心 2025年第6期1113-1122,共10页
加卸载判断和繁琐的解析求导运算一直是制约先进弹塑性模型数值应用的瓶颈问题。研究提出一种基于超对偶数微分方法的无约束应力隐式更新算法,有效解决了上述计算难点。针对加卸载判断问题,新算法利用光滑函数代替弹塑性本构方程组中的K... 加卸载判断和繁琐的解析求导运算一直是制约先进弹塑性模型数值应用的瓶颈问题。研究提出一种基于超对偶数微分方法的无约束应力隐式更新算法,有效解决了上述计算难点。针对加卸载判断问题,新算法利用光滑函数代替弹塑性本构方程组中的Karush-Kuhn-Tucker条件,将受不等式约束的非线性应力积分方程组问题,转化为无约束的最小化问题,计算时无需加卸载判断。针对导数计算问题,新算法利用超对偶数微分方法代替解析求导,获得光滑函数的1阶导数以及塑性势函数的1阶和2阶导数,用于构造非线性计算的迭代公式,以保证局部应力更新迭代和全局平衡迭代的二次收敛速度。数值算例表明,相较于其它数值微分方法,超对偶数微分方法不受截断误差和减法消去误差影响,计算结果等同于解析求导。最后,基于所提算法编写了光滑莫尔库仑塑性模型的UMAT子程序,并通过3个典型边值问题的数值分析,验证了算法的有效性和收敛性速度。 展开更多
关键词 应力更新算法 塑性模型 超对偶数数值微分 一致性切线刚度矩阵 有限元法
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