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改进L-M法的箝位型逆变器SHEPWM求解方法 被引量:2
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作者 陈金平 贺昱曜 +2 位作者 王宽 巨永锋 周熙炜 《高电压技术》 EI CAS CSCD 北大核心 2015年第7期2400-2407,共8页
针对Newton-Raphson(N-R)法求解二极管箝位型(NPC)逆变器选择性谐波消除脉宽调制(SHEPWM)的非线性方程组时存在初始值选取困难的问题,提出了一种改进Levenberg-Marquardt(L-M)法。改进L-M法通过在求逆矩阵中引入阻尼因子,克服了N-R法Jac... 针对Newton-Raphson(N-R)法求解二极管箝位型(NPC)逆变器选择性谐波消除脉宽调制(SHEPWM)的非线性方程组时存在初始值选取困难的问题,提出了一种改进Levenberg-Marquardt(L-M)法。改进L-M法通过在求逆矩阵中引入阻尼因子,克服了N-R法Jacobi矩阵不可逆或病态的不足;通过自适应调整松弛参数以降低迭代初始值的选取难度,并减少了矩阵求逆次数和计算量。以调制度m=0.85时9个开关角的NPC逆变器SHEPWM为例,随机选取6组初始值,通过合理选取阻尼因子和在线自适应调节松弛参数,得到了满足要求的6组数值解;并验证了改进L-M法的收敛域明显宽于N-R法;分析了6组初始值在m∈[0.7,1.15]的解轨迹及其谐波特性的差异,为实际应用优化选择提供了依据。最后,通过单相实验验证了新方法所得解的正确性。 展开更多
关键词 箝位型逆变器 选择谐波消除 非线性方程 改进Levenberg-Marquardt法 初始值 多组解
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IBM4381线性规划求解程序
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作者 金桂三 《辽宁石油化工大学学报》 CAS 1992年第1期45-50,共6页
本文介绍的软件用全屏幕编辑程序XEDTD直接在屏幕编辑方程,则自动生成初始元素表并求解,对有多组解的线性规划问题,谈软件能给出所有的最优解。
关键词 用XEDIT输入数据 初始元素表的自动生成 多组最优
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供应链中供应商选择决策方法 被引量:13
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作者 张树梁 陈友玲 张豆 《计算机应用研究》 CSCD 北大核心 2015年第4期1024-1027,1031,共5页
为了克服传统供应商选择过程中面向单一解的局限性,更好地解决供应链中供应商选择的多目标优化问题,达到费用和效益最佳,以产品价格、质量、交货可靠性和交货提前期为评估指标,建立了供应商选择多目标优化模型。首次将SPEA2算法应用于... 为了克服传统供应商选择过程中面向单一解的局限性,更好地解决供应链中供应商选择的多目标优化问题,达到费用和效益最佳,以产品价格、质量、交货可靠性和交货提前期为评估指标,建立了供应商选择多目标优化模型。首次将SPEA2算法应用于供应商选择问题,构造了适合该模型特征的SPEA2算法求解过程,可针对多个求解目标获得一组均衡解。模拟算例中一次得到多组有效解,表明所建立模型及所用方法是有效、可行的,它为制造企业获得有多种解决方案的供应商选择问题提供了可参考的模型和求解算法。 展开更多
关键词 供应商选择 多目标优化 SPEA2算法 多组有效
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基于多组最优解的银行资产负债多目标优化模型构建 被引量:12
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作者 周颖 柳煦 《管理评论》 CSSCI 北大核心 2018年第6期13-27,共15页
建立基于资产已有的巨额存量组合和待配置的增量组合的全部资产组合的偿债能力、流动性风险、收益三重目标的资产优化配置模型,兼顾"存量+增量"的全部组合资产的流动性、安全性和收益性,优化配置资产。通过层次算法解出多组... 建立基于资产已有的巨额存量组合和待配置的增量组合的全部资产组合的偿债能力、流动性风险、收益三重目标的资产优化配置模型,兼顾"存量+增量"的全部组合资产的流动性、安全性和收益性,优化配置资产。通过层次算法解出多组、而非一组最优解,保证银行可以在多组优先顺序的最优解中根据实际情况选择切合实际的一组最优解。多组最优解对银行管理的意义在于它可以满足不同银行管理层的价值偏好,追求那个主要目标的最优都可以兼顾其他目标满足和次优。这使银行可视宏观环境、经营战略等变化,选择最适宜的一组优先级次序,制定最优资产负债管理方案,有效、灵活地对银行未来资产优化配置。对宁波银行的实证也表明,不同优先级次序对应的6组最优解都兼顾了流动性、安全性和盈利性三重目标,且目标优先级越高,满足效果越好。 展开更多
关键词 资产负债管理 存量 增量 全部合配置 多组最优
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Existence of multi-bump solutions for coupled Schr dinger systems
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作者 李玉祥 温学飞 《Journal of Southeast University(English Edition)》 EI CAS 2012年第4期496-501,共6页
The Schrodinger equation -△u+λ2u=|u|2q-2u has a unique positive radial solution Uλ, which decays exponentially at infinity. Hence it is reasonable that the Schrolinger system -△u1+u1=|u1|2q-1u1-εb(x)|u2... The Schrodinger equation -△u+λ2u=|u|2q-2u has a unique positive radial solution Uλ, which decays exponentially at infinity. Hence it is reasonable that the Schrolinger system -△u1+u1=|u1|2q-1u1-εb(x)|u2|1|u1|q-1u1,-△u2+u2=|u2|2q-2u2-εb(x)|u1|1|u2|q-1u2 has multiple-bump solutions which behave like Uλ in the neighborhood of some points. For u=(u1,u2)∈H1(R3)×H1(R3), a nonlinear functional Iε(u)=I1(u1)+I2(u2)-ε/q∫R3b(x)|u1|q|u2|qdx,is defined,where I1(u1)=1/2||u1||2-1/2q∫R3|u1|2qdx and I2(u2)=1/2||u2||2ω-1/2q∫R3|u2|2qdx. It is proved that the solutions of the system are the critical points of I,. Let Z be the smooth solution manifold of the unperturbed problem and TzZ is the tangent space. The critical point of I is rewritten as the form of z + w, where w ∈ (TzZ)⊥. Using some properties of Iε, it is proved that there exists a critical point of I, close to the form which is a multi-bump solution. 展开更多
关键词 coupled Schrodinger system multi-bump solution variational reduction method
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Exact Periodic and Solitary-Wave Solutions of Multi-component Modified Korteweg-de Vries Equations
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作者 ZHANG Huan TIAN Bo +1 位作者 ZHANG Hai-Qiang LI Li-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第4期588-594,共7页
The present work extends the search of Jacobi elliptic function solutions for the multi-component modified Korteweg-de Vries equations. When the modulum m →1, those periodic solutions degenerate as the corresponding ... The present work extends the search of Jacobi elliptic function solutions for the multi-component modified Korteweg-de Vries equations. When the modulum m →1, those periodic solutions degenerate as the corresponding solitary wave and shock wave ones. Especially, exact solutions for the three-component system are presented in detail and graphically. 展开更多
关键词 multi-component modified Korteweg-de Vries equations Jacobi elliptic function Hyperbolic solution symbolic computation
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Separation of Proteins by Electrophoretic Affinity Chromatography
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作者 酆韶骅 刘铮 +1 位作者 丁富新 袁乃驹 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1999年第4期315-320,共6页
A new kind of electrophoretic affinity chromatography (EAC) for bioseparation was proposed. Separation by EAC was conducted in a multicompartment electrolyzer in which the affinity gel media were packed in one of the ... A new kind of electrophoretic affinity chromatography (EAC) for bioseparation was proposed. Separation by EAC was conducted in a multicompartment electrolyzer in which the affinity gel media were packed in one of the central compartments. The presence of an electric field accelerated the migration of proteins inside the gel matrix during adsorption and desorption processes. This led to the increase of the overall speed of separation. The present study was focused on the effect of the strength of the electric field on adsorption and desorption processes. 展开更多
关键词 affinity chromatography ELECTROPHORESIS electrophoretic affinity chromatography human serum albumin Cibacron Blue F3G-A
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Integrability Aspects and Soliton Solutions for a System Describing Ultrashort Pulse Propagation in an Inhomogeneous Multi-Component Medium
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作者 郭睿 田播 +2 位作者 吕兴 张海强 许韬 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第9期536-544,共9页
For the propagation of the ultrashort pulses in an inhomogeneous multi-component nonlinear medium, a system of coupled equations is analytically studied in this paper. Painleve analysis shows that this system admits t... For the propagation of the ultrashort pulses in an inhomogeneous multi-component nonlinear medium, a system of coupled equations is analytically studied in this paper. Painleve analysis shows that this system admits the Painleve property under some constraints. By means of the Ablowitz-Kaup-Newell-Segur procedure, the Lax pair of this system is derived, and the Darboux transformation (DT) is constructed with the help of the obtained Lax pair. With symbolic computation, the soliton solutions are obtained by virtue of the DT algorithm. Figures are plotted to illustrate the dynamical features of the soliton solutions. Characteristics of the solitons propagating in an inhomogeneous multi-component nonlinear medium are discussed: (i) Propagation of one soliton and two-peak soliton; (ii) Elastic interactions of the parabolic two solitons; (iii) Overlap two head-on solitons and two head-on two-peak solitons; (v) Two (vi) Decomposition phenomenon of one soliton into two solitons. phenomenon between two solitons; (iv) Collision of different types of interactions of the three solitons; ultrashort-pulse propagation in the inhomogeneous multi-component The results might be useful in the study on the nonlinear media. 展开更多
关键词 ultrashort pulses Painleve analysis Lax pair Darboux transformation SOLITON symbolic computation
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Layout problem of multi-component systems arising for improving maintainability 被引量:5
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作者 罗旭 杨拥民 +2 位作者 葛哲学 温熙森 官凤娇 《Journal of Central South University》 SCIE EI CAS 2014年第5期1833-1841,共9页
To improve the mainlainability design efficiency and quality, a layout optimization method for maintainability of multi-component systems was proposed. The impact of the component layout design on system maintainabili... To improve the mainlainability design efficiency and quality, a layout optimization method for maintainability of multi-component systems was proposed. The impact of the component layout design on system maintainability was analyzed, and the layout problem for maintainability was presented. It was formulated as an optimization problem, where maintainability, layout space and distance requirement were formulated as objective functions. A multi-objective particle swarm optimization algorithm, in which the constrained-domination relationship and the update strategy of the global best were simply modified, was then used to obtain Pareto optimal solutions for the maintainability layout design problem. Finally, application in oxygen generation system of a spacecraft was studied in detail to illustrate the effectiveness and usefulness of the proposed method. The results show that the concurrent maintainability design can be carried out during the layout design process by solving the layout optimization problem for maintainability. 展开更多
关键词 MAINTAINABILITY layout problem OPTIMIZATION multi-component system multi-objective particle swarm optimization
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Controlled Release of the Indomethacin Microencapsulation Based on Layer-by-layer Assembly by Polyelectrolyte Multilayers
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作者 CHEN You-fang LIN Xian-fu 《Chinese Journal of Biomedical Engineering(English Edition)》 2007年第1期8-13,共6页
Indomethacin has been encapsulated with polyelectrolyte multilayers for controlled release. Gelatin and alginate were alternatively deposited on indomethacin microcrystals. The released amount of indomethacin from coa... Indomethacin has been encapsulated with polyelectrolyte multilayers for controlled release. Gelatin and alginate were alternatively deposited on indomethacin microcrystals. The released amount of indomethacin from coated microcrystals in pH6. 8 phosphate buffer solution (PBS) was measured with a UV spectrophometer. The polyelectrolyte multilayer capsule thickness was proved to control the release rate. The effects of osmotic pressure existed during the release process of indomethacin from microcapsules coated by (gelatin/alginate) 4. 展开更多
关键词 INDOMETHACIN ENCAPSULATED Controlled release SELF-ASSEMBLY POLYELECTROLYTE
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multi-solitons interaction multicomponent plasma extended Poincare–Lighthill–Kuo method head-on collision
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作者 Kaushik Roy Malay Kumar Ghorui +1 位作者 Prasanta Chatterjee Mouloud Tribeche 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第2期237-246,共10页
The propagation and interaction between ion acoustic multi-solitons in an unmagnetized multicomponent plasma consisting of fluid hot ions, positrons and both hot and cold electrons, are investigated by employing the e... The propagation and interaction between ion acoustic multi-solitons in an unmagnetized multicomponent plasma consisting of fluid hot ions, positrons and both hot and cold electrons, are investigated by employing the extended Poincare–Lighthill–Kuo(PLK) method. Two different Kortewege-de Vries(K-dV) equations are derived. The Hirota's method is applied to get the K-dV multi-solitons solution. The phase shift due to the overtaking and head- on collision of the multi-solitons is obtained. 展开更多
关键词 Head-on Collision of Ion-acoustic Multi-Solitons in e-p-i Plasma
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