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动力系统非线性行为识别方法与验证 被引量:5
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作者 许斌 贺佳 Sami F.Masri 《土木工程学报》 EI CSCD 北大核心 2011年第S1期24-30,共7页
在构建动力非线性系统恢复力的幂级数多项式模型的基础上,提出一种完全基于结构激励和响应时间序列的非线性恢复力识别方法,并通过一个带非线性构件(磁流变阻尼器)的四层结构模型在不同激励方式下的动力测试数据对该方法的有效性进行验... 在构建动力非线性系统恢复力的幂级数多项式模型的基础上,提出一种完全基于结构激励和响应时间序列的非线性恢复力识别方法,并通过一个带非线性构件(磁流变阻尼器)的四层结构模型在不同激励方式下的动力测试数据对该方法的有效性进行验证。有别于传统的系统识别方法,本方法不需要已知结构质量分布,也不需要提取系统特征值信息,而是直接根据系统时域信息进行恢复力识别。对于结构各自由度均受到外激励的情况,基于实测数据,运用最小二乘优化算法识别出恢复力模型的各个参数,进而得到模型振动过程中磁流变阻尼器提供的阻尼力随时间的变化情况,并与试验实测结果进行比较。针对结构仅有部分自由度受外激励的情况,对以上方法进行扩展,分步确定结构各层间恢复力并与实测结果进行比较。结果表明,该非线性恢复力识别法无论在结构全部或者部分自由度受激励的情况下均能有效地识别出结构的非线性恢复力,可为土木工程结构在地震等动力荷载作用下的损伤评估提供新的方法。 展开更多
关键词 非线性恢复力 幂级数多项式模型 磁流变阻尼器 最小二乘拟合 实测数据 全部激励 部分激励
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确定学习与基于数据的建模及控制 被引量:19
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作者 王聪 陈填锐 刘腾飞 《自动化学报》 EI CSCD 北大核心 2009年第6期693-706,共14页
确定学习运用自适应控制和动力学系统的概念与方法,研究未知动态环境下的知识获取、表达、存储和利用等问题.针对产生周期或回归轨迹的连续非线性动态系统,确定学习可以对其未知系统动态进行局部准确建模,其基本要素包括:1)使用径向基函... 确定学习运用自适应控制和动力学系统的概念与方法,研究未知动态环境下的知识获取、表达、存储和利用等问题.针对产生周期或回归轨迹的连续非线性动态系统,确定学习可以对其未知系统动态进行局部准确建模,其基本要素包括:1)使用径向基函数(Radial basis function,RBF)神经网络;2)对于周期(或回归)状态轨迹满足部分持续激励条件;3)在周期(或回归)轨迹的邻域内实现对非线性系统动态的局部准确神经网络逼近(局部准确建模);4)所学的知识以时不变且空间分布的方式表达、以常值神经网络权值的方式存储,并可在动态环境下用于动态模式的快速识别或者闭环神经网络控制.本文针对离散动态系统,扩展了确定学习理论,提出一个根据时态数据序列对离散动态系统进行建模与控制的框架.首先,运用确定学习原理和离散系统的自适应辨识方法,实现对产生时态数据的离散非线性系统的未知动态进行局部准确的神经网络建模,并利用此建模结果对时态数据序列进行时不变表达.其次,提出时态数据序列的基于动力学的相似性定义,以及对离散动态系统产生的时态数据序列(亦可称为动态模式)进行快速识别方法.最后,针对离散非线性控制系统,实现了基于时态数据序列对控制系统动态的闭环辨识(局部准确建模).所学关于闭环动态的知识可用于基于模式的智能控制.本文表明确定学习可以为时态数据挖掘的研究提供新的途径,并为基于数据的建模与控制等问题提供新的研究思路. 展开更多
关键词 确定学习 时态数据序列 离散动态系统 基于数据的建模 部分持续激励条件 时态数据挖掘 动态模式识别 基于模式的控制
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Localized Excitations of (2+1)-Dimensional Korteweg-de Vries System Derived from a Periodic Wave Solution
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作者 QIANG Ji-Ye FEI Jin-Xi +1 位作者 CAI Gui-Ping ZHENG Chun-Long 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第2期275-281,共7页
With the aid of an improved projective approach and a linear variable separation method, new types of variable separation solutions (including solitary wave solutions, periodic wave solutions, and rational function s... With the aid of an improved projective approach and a linear variable separation method, new types of variable separation solutions (including solitary wave solutions, periodic wave solutions, and rational function solutions) with arbitrary functions for (2+1)-dimensional Korteweg-de Vries system are derived. Usually, in terms of solitary wave solutions and rational function solutions, one can find some important localized excitations. However, based on the derived periodic wave solution in this paper, we find that some novel and significant localized coherent excitations such as dromions, peakons, stochastic fractal patterns, regular fractal patterns, chaotic line soliton patterns as well as chaotic patterns exist in the KdV system as considering appropriate boundary conditions and/or initial qualifications. 展开更多
关键词 improved projective approach KdV system chaos SOLITON FRACTAL
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1kW全固态中波发射机的改频
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作者 高强 《西部广播电视》 2016年第16期240-240,245,共2页
本文主要介绍1 k W全固态中波发射机的改频具体操作方法,主要包括输出网络、功放部分及激励部分调整。
关键词 改频 输出网络 功放部分 激励部分
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Study on (2+1)-Dimensional Nizhnik-Novikov-Veselov Equation by Using Extended Mapping Approach
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作者 XU Chang-Zhi HE Bao-Gang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第1X期10-14,共5页
Extended mapping approach is introduced to solve (2+1)-dimensional Nizhnik-Novikov Veselov equation. A new type of variable separation solutions is derived with arbitrary functions in the model. Based on this excit... Extended mapping approach is introduced to solve (2+1)-dimensional Nizhnik-Novikov Veselov equation. A new type of variable separation solutions is derived with arbitrary functions in the model. Based on this excitation, rich localized structures such as multi-lump soliton and ring soliton are revealed by selecting the arbitrary function appropriately. 展开更多
关键词 extended mapping approach (2+1)-dimensional Nizhnik-Novikov-Veselov equation new localized excitation
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Research on Incentive Mechanism of Virtual Community Knowledge Sharing
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作者 ZHANG Ying 《International English Education Research》 2017年第4期56-59,共4页
With the continuous development of Internet technology, the network has become an important part of people's lives, the emergence of virtual communities is promoting the deep interaction oflntemet users, but it is fo... With the continuous development of Internet technology, the network has become an important part of people's lives, the emergence of virtual communities is promoting the deep interaction oflntemet users, but it is found that the virtual community "diving party" is more and more through investigation and literature research, The quantity and quality of knowledge sharing are declining. Therefore, this paper summarizes the behavior and influencing factors of knowledge sharing in virtual community through literature research and investigation and research. At the same time, through the research of incentive theory, the author has obtained the incentive method and content of knowledge sharing, and established the incentive mechanism. The bright spot is to perfect the theory of knowledge sharing while transforming theory into practice, and to provide suggestions for the development of incentive mechanism of virtual community. 展开更多
关键词 Virtual Community Influencing Factor Incentive Mechanism Theoretical Research
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来稿摘编
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《四川财政》 1999年第4期60-61,共2页
“先征后返”政策应适可而止四川省财政厅税政处陈汝兴“先征后返”作为一种特殊的财政资金管理形式,其主要弊端有:一是导致了财政资金大量流失。1994年至今,各地用“先征后返”等办法大开减免税口子,地方税种几乎无税不涉,遍... “先征后返”政策应适可而止四川省财政厅税政处陈汝兴“先征后返”作为一种特殊的财政资金管理形式,其主要弊端有:一是导致了财政资金大量流失。1994年至今,各地用“先征后返”等办法大开减免税口子,地方税种几乎无税不涉,遍及大多数行业和经济类型的纳税人,而... 展开更多
关键词 经营者 年薪制 先征后返 乡镇财政 预算外资金管理 财政收入 激励部分 饭店业 乡镇预算 企业家市场
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Wind Generation in the Argentine Power System
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作者 Juan Manuel Gimenez-Alvarez: Gustavo Schweickard 《Journal of Energy and Power Engineering》 2012年第11期1862-1868,共7页
Energy policy is an essential part of the economy and the society. In some countries, there is a lack of a regulatory framework, which must be clear and practicable to allow new technologies to compete with the conven... Energy policy is an essential part of the economy and the society. In some countries, there is a lack of a regulatory framework, which must be clear and practicable to allow new technologies to compete with the conventional way of generation. This is the problem in Argentine, the lack of a regulatory framework that can regulate the insertion of wind energy into the Argentine power system (SADI). In this paper, a review of typical incentives for the installation of wind farms in the world, and a review of some laws and policies in Argentine are presented. Also financial and economic issues that are related to the installation of wind farms are analyzed, and some recommendations related to the topics are presented in this paper. 展开更多
关键词 Wind generation Argentinean laws related to wind generation Argentinean regulation and programs.
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