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求解偏微分方程的深度学习方法概述
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作者 邹青松 韦平 +2 位作者 陈辽 岑鉴焕 谭凯耀 《人工智能》 2024年第5期17-34,共18页
数值求解偏微分方程是多学科计算领域共同关注的一项基础科学课题。近年来,神经网络的深度学习方法得到了大力的发展,这一方法也被引入求解偏微分方程这一领域,逐渐成为了科学计算领域的研究热点之一。为此,本文介绍了近些年求解偏微分... 数值求解偏微分方程是多学科计算领域共同关注的一项基础科学课题。近年来,神经网络的深度学习方法得到了大力的发展,这一方法也被引入求解偏微分方程这一领域,逐渐成为了科学计算领域的研究热点之一。为此,本文介绍了近些年求解偏微分方程的一些深度学习方法,将这些深度学习方法从数学角度分为函数学习类方法和算子类学习方法。本文将对这两类深度学习方法的研究现状进行梳理以及总结,同时还简要介绍了目前深度学习方法在求解偏微分方程中遇到的一些困难和挑战,并对可能的研究趋势和方向进行了预测。 展开更多
关键词 深度学习方法 偏微分方程 算子学习方法 函数学习方法
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基于多岛遗传算法的翼型多目标优化设计
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作者 张之阳 刘旭 +3 位作者 吴林艳 陈少华 刘葳兴 崔琳 《中国舰船研究》 CSCD 北大核心 2024年第4期148-155,共8页
[目的]针对大型水平轴水轮机叶片运行工况复杂的问题,提出一种多目标优化算法。[方法]基于多岛遗传算法建立翼型优化模型,采用类形函数变换(CST)法对翼型进行参数化拟合,整个优化过程集成于Isight平台,实现自动优化。[结果]采用上述方法... [目的]针对大型水平轴水轮机叶片运行工况复杂的问题,提出一种多目标优化算法。[方法]基于多岛遗传算法建立翼型优化模型,采用类形函数变换(CST)法对翼型进行参数化拟合,整个优化过程集成于Isight平台,实现自动优化。[结果]采用上述方法,选用NACA 63813/63815/63816翼型作为初始翼型进行多目标优化,利用Fluent转捩模型对得到的翼型进行CFD数值验证,选择翼型攻角5°时的升阻比、升力等为优化目标参数,得到优化后的翼型升力系数分别增大了14%,15%,20%,升阻比分别增大了14%,16%,28%。[结论]数值验证结果表明,优化后的翼型在多个工况点下的升阻比均高于同厚度原始翼型,在具有良好的水动力动性能的同时还提高了叶片的结构强度,相比于传统的翼型更适用于大型潮流能水平轴水轮机。 展开更多
关键词 水轮机 多岛遗传算法 多目标优化 翼型 函数变换参数化方法
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中国各省区竞技体育效率评估的模式研究 被引量:12
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作者 李淞淋 李联堂 《成都体育学院学报》 CSSCI 北大核心 2014年第2期26-32,共7页
竞技体育效率研究可用于评估一个国家或地区向体育运动的投资效率,寻找竞技体育效率发展的影响因素,为进一步提高当地的体育水平提供思路。采用包络分析方法和基于面板数据的K-中心函数聚类方法分析中国31个省、市、区在1994-2013年期... 竞技体育效率研究可用于评估一个国家或地区向体育运动的投资效率,寻找竞技体育效率发展的影响因素,为进一步提高当地的体育水平提供思路。采用包络分析方法和基于面板数据的K-中心函数聚类方法分析中国31个省、市、区在1994-2013年期间的经济、人口和全运会奖牌情况,发现区域竞技体育效率发展趋势明显存在较大差异;结合各省区的实际情况,具体地将31个省(市)具体分为经济主导型高效率组、人口主导型高效率组、经济优势型低效率组、人口优势型低效率组、双优势型低效率组五种竞技体育效率发展模式;研究讨论了每种模式下竞技体育效率上升或下降的原因,为将来提升各省、市、区的竞技体育效率提供建议。 展开更多
关键词 DEA K-中心函数方法 面板数据 竞技体育效率
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New Multiple Soliton-like and Periodic Solutions for (2+l)-Dimensional Canonical Generalized KP Equation with Variable Coefficients 被引量:3
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作者 ZHANG Li-Hua LIU Xi-Qiang BAI Cheng-Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5X期793-798,共6页
In this paper, the generalized ranch function method is extended to (2+1)-dimensianal canonical generalized KP (CGKP) equation with variable coetfficients. Taking advantage of the Riccati equation, many explicit ... In this paper, the generalized ranch function method is extended to (2+1)-dimensianal canonical generalized KP (CGKP) equation with variable coetfficients. Taking advantage of the Riccati equation, many explicit exact solutions, which contain multiple soliton-like and periodic solutions, are obtained for the (2+1)-dimensional OGKP equation with variable coetffcients. 展开更多
关键词 (2+1)-dimensional canonical generalized (CGKP) equation with variable coefficients tanh function method Riccati equation soliton-like and periodic solutions
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Preliminary Group Classification for One Class of Nonlinear Wave Equations 被引量:1
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作者 李吉娜 张颖 张顺利 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第8期229-235,共7页
The group classification is carried out on the nonlinear wave equation utt = f(x,u, ux)uzz + g(x,u,uz) by using the preliminary group classification approach. The generators of equivalence group are determined an... The group classification is carried out on the nonlinear wave equation utt = f(x,u, ux)uzz + g(x,u,uz) by using the preliminary group classification approach. The generators of equivalence group are determined and the corresponding reduced forms are obtained. The result of the work is shown in table form. 展开更多
关键词 preliminary group classification optimal system nonlinear wave equation
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Analysis to Some Solutions Obtained by Modified Extended tanh-Function Method
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作者 刘春平 林支桂 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第11期781-784,共4页
First, two tanh-coth type solutions of a class of nonlinear wave equation are derived by using a simplified modified extended tanh-function method. Then, further analysis to some tanh-coth type solutions of nonlinear ... First, two tanh-coth type solutions of a class of nonlinear wave equation are derived by using a simplified modified extended tanh-function method. Then, further analysis to some tanh-coth type solutions of nonlinear evolution equations are given. The results show that when balance number m is one or two, the tanh-eoth type solutions obtained by the modified extended tanh-funetion method can be obtained by using the hyperbolic-function method. 展开更多
关键词 modified extended tanh-function method travelling wave solution a class of nonlinear waveequation hyperbolic-function method
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面对他们,我惊叹不已——均值不等式定理的证明 被引量:3
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作者 陈传熙 《中学数学教学参考(教师版)》 2004年第11期23-25,共3页
关键词 均值不等式定理 定理证明 数学教学 证明思路 课题研究 代数方法 函数类方法
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Order and Type of the Generalized Dirichlet Series 被引量:2
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作者 黄文平 宁菊红 涂金 《Journal of Mathematical Research and Exposition》 CSCD 2009年第6期1041-1046,共6页
For an entire function represented by a generalized dirichlet series, we define its maximal term, maximal modulus, order and type. We use the classical methods to study the relation between order, type and coeFFIcient... For an entire function represented by a generalized dirichlet series, we define its maximal term, maximal modulus, order and type. We use the classical methods to study the relation between order, type and coeFFIcients, exponents, which improve and generalize some results of the dirichlet series with real exponents. 展开更多
关键词 maximal term order type maximal modulus.
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Symmetries,Integrability and Exact Solutions to the (2+1)-Dimensional Benney Types of Equations 被引量:1
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作者 刘汉泽 辛祥鹏 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第8期155-162,共8页
This paper is concerned with the (2+1)-dimensional Benney types of equations. By the complete Lie group classification method, all of the point symmetries of the Benney types of equations are obtained, and the integra... This paper is concerned with the (2+1)-dimensional Benney types of equations. By the complete Lie group classification method, all of the point symmetries of the Benney types of equations are obtained, and the integrable condition of the equation is given. Then, the symmetry reductions and exact solutions to the (2+1)-dimensional nonlinear wave equations are presented. Especially, the shock wave solutions of the Benney equations are investigated by the symmetry reduction and trial function method. 展开更多
关键词 Benney equation symmetry integrability exact solution shock wave solution
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GLOBAL CONVERGENCE OF A CLASS OF SMOOTH PENALTY METHODS FOR SEMI-INFINITE PROGRAMMING
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作者 Changyu WANG Haiyan ZHANG Fang LIU 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2011年第4期769-783,共15页
For the semi-infinite programming (SIP) problem, the authors first convert it into an equivalent nonlinear programming problem with only one inequality constraint by using an integral function, and then propose a sm... For the semi-infinite programming (SIP) problem, the authors first convert it into an equivalent nonlinear programming problem with only one inequality constraint by using an integral function, and then propose a smooth penalty method based on a class of smooth functions. The main feature of this method is that the global solution of the penalty function is not necessarily solved at each iteration, and under mild assumptions, the method is always feasible and efficient when the evaluation of the integral function is not very expensive. The global convergence property is obtained in the absence of any constraint qualifications, that is, any accumulation point of the sequence generated by the algorithm is the solution of the SIP. Moreover, the authors show a perturbation theorem of the method and obtain several interesting results. Furthermore, the authors show that all iterative points remain feasible after a finite number of iterations under the Mangasarian-Fromovitz constraint qualification. Finally, numerical results are given. 展开更多
关键词 Global convergence semi-infinite programming smooth penalty function perturbation function.
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