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仿射非线性系统的动态反馈线性化与系统线性近似的能控性
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作者 张仁忠 《哈尔滨师范大学自然科学学报》 CAS 2003年第1期24-26,共3页
本文用微分几何方法讨论了m=n-1仿射非线性系统的动态反馈线性化与系统的线性近似能控性的关系,给出了系统可动态反馈线性化的条件.
关键词 仿射非线性系统 能控性 对合分布 动态反馈线性 系统线性近似 微分几何方法
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仿射非线性系统的动态反馈线性化与系统线性近似的能控性
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作者 张仁忠 李效民 《通化师范学院学报》 2003年第2期1-3,共3页
用微分几何方法讨论了m =n - 1仿射非线性系统的动态反馈线性化与系统的线性近似能控性的关系 ,给出了系统可动态反馈线性化的条件 .
关键词 仿射 能控性 线性系统 对合分布 动态反馈线性 系统线性近似 微分几何方法
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一类相互竞争模型的分析
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作者 方辉平 《皖西学院学报》 2004年第5期16-17,共2页
利用定性理论分析一类特殊的相互竞争模型,得出平衡态的稳定性以及物种的最终数量。
关键词 物种竞争 相互竞争模型 竞争排斥原理 无量纲化 平衡态 线性近似系统
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一类简化Fitzhugh-Nagumo方程的定性分析 被引量:1
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作者 康宏春 陈冲 刘启宽 《河北科技大学学报》 CAS 北大核心 2011年第3期208-211,共4页
应用线性近似理论和拓扑结构的不变性得到简化Fitzhugh-Nagumo方程对应的二维系统在有限奇点的性质,并运用Dulac判别法讨论了该问题极限环的不存在性。
关键词 FITZHUGH-NAGUMO方程 有限奇点 高阶奇点 线性近似系统
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Solution of Travelling Wave for Nonlinear Disturbed Long-Wave System 被引量:33
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作者 MO Jia-Qi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第3期387-390,共4页
The approximate expressions of the travelling wave solutions for a class of nonlinear disturbed long-wave system are constructed using the generalized variational iteration method.
关键词 nonlinear long-wave equation travelling wave approximate analytic solution
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Approximate Analytic Solution of Solitary Wave for a Class of Nonlinear Disturbed Long-Wave System 被引量:5
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作者 莫嘉琪 姚静荪 唐荣荣 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第7期27-30,共4页
In this paper, the approximate expressions of the solitary wave solutions for a class of nonlinear disturbed long-wave system are constructed using the homotopie mapping method.
关键词 nonlinear long-wave equation solitary wave approximate analytic solution
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Approximate Generalized Conditional Symmetries for Perturbed Evolution Equations 被引量:3
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作者 ZHANG Shun-Li WANG Yong LOU Sen-Yue 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第6期975-980,共6页
The concept of approximate generalized conditional symmetry (AGCS) for the perturbed evolution equations is introduced, and how to derive approximate conditional invariant solutions to the perturbed equations via th... The concept of approximate generalized conditional symmetry (AGCS) for the perturbed evolution equations is introduced, and how to derive approximate conditional invariant solutions to the perturbed equations via their A GCSs is illustrated with examples. 展开更多
关键词 perturbed evolution equation approximate generalized conditional symmetry approximate con ditional invariant solution
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Estimating the Fresh Vegetables Demand System in Jordan: A Linear Approximate Almost Ideal Demand System
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作者 A. S. Jabarin E. K. Al-Karablieh 《Journal of Agricultural Science and Technology》 2011年第3期322-331,共10页
The main objective of this research is to estimate the different types of demand elasticities for the main fresh vegetables consumed in Jordan. The estimated elasticities can be used to measure the impacts of agricult... The main objective of this research is to estimate the different types of demand elasticities for the main fresh vegetables consumed in Jordan. The estimated elasticities can be used to measure the impacts of agricultural policies and can be used to predict future consumption in the context of food security in terms of access, availability, stability, and food quality. The reported demand estimates were obtained through the estimation of a Linear Approximate Almost Ideal Demand Systems (LA/AIDS) for Jordan fresh vegetable crops demand system using the most recent cross-sectional data of household expenditure survey in 2005. A censored regression method for the system of equations was used to analyze fresh vegetables consumption patterns. This method allows for inclusion of a large number of zero consumption for some foods through two-step demand system estimation. All of the own-price demand elasticities have the correct negative signs and statistically significant. According to the expenditure elasticity, tomato, cucumber, and potato are the necessity goods. The mean budget shares indicate that consumers spend 30 percent of their allocated budget to vegetables on tomatoes and potatoes. The green bean elasticity is the highest indicating that demand for beans is highly responsive to any changes in the price. The expenditure elasticities reveal that the demand on all vegetables is expected to grow over the coming few years. High own-price elasticities of all vegetables studied suggests that any changes in the prices of these crops could bring about a significant shift in fruits and vegetable constanption patterns. 展开更多
关键词 Vegetable demand system demand elasticities LA/AIDS model Marshallian and Hicksian elasticities censored regression probit model.
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Optimal and suboptimal white noise smoothers for nonlinear stochastic systems
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作者 王小旭 潘泉 +1 位作者 梁彦 程咏梅 《Journal of Central South University》 SCIE EI CAS 2013年第3期655-662,共8页
A new approach of smoothing the white noise for nonlinear stochastic system was proposed. Through presenting the Gaussian approximation about the white noise posterior smoothing probability density fimction, an optima... A new approach of smoothing the white noise for nonlinear stochastic system was proposed. Through presenting the Gaussian approximation about the white noise posterior smoothing probability density fimction, an optimal and unifying white noise smoothing framework was firstly derived on the basis of the existing state smoother. The proposed framework was only formal in the sense that it rarely could be directly used in practice since the model nonlinearity resulted in the intractability and infeasibility of analytically computing the smoothing gain. For this reason, a suboptimal and practical white noise smoother, which is called the unscented white noise smoother (UWNS), was further developed by applying unscented transformation to numerically approximate the smoothing gain. Simulation results show the superior performance of the proposed UWNS approach as compared to the existing extended white noise smoother (EWNS) based on the first-order linearization. 展开更多
关键词 nonlinear stochastic system white noise smoother optimal framework unscented transformation
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Effects of Pressure Stress Work and Viscous Dissipation in Mixed Convection Flow Along a Vertical Flat Plate
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作者 A.S. Bhuiyan J. M. Alam M. R. Biswas 《Journal of Mathematics and System Science》 2013年第3期115-121,共7页
The Effects of pressure stress work and viscous dissipation in mixed convection flow along a vertical fiat plate have been investigated. The results are obtained by transforming the governing system of boundary layer ... The Effects of pressure stress work and viscous dissipation in mixed convection flow along a vertical fiat plate have been investigated. The results are obtained by transforming the governing system of boundary layer equations into a system of non-dimensional equations and by applying implicit finite difference method together with Newton's linearization approximation. Numerical results for different values of pressure stress work parameter, viscous dissipation parameter and Prandtl number have been obtained. The velocity profiles, temperature distributions, skin friction co-efficient and the rate of heat transfer have been presented graphically for the effects of the aforementioned parameters. 展开更多
关键词 Mixed convection viscous dissipation pressure stress work.
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中国农村家庭食物需求分析(英文) 被引量:1
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作者 许世卫 喻闻 王禹 《营养学报》 CAS CSCD 北大核心 2015年第2期189-195,共7页
目的本研究旨在测度收入和其他社会经济变量如家庭规模对食品和营养需求的作用。方法这项研究使用最近的国家统计局农村调查数据,测度中国农村家庭的食物和营养的需求;线性近似几乎理想的需求系统(LA/AIDS)是用来估计价格和支出弹性,以... 目的本研究旨在测度收入和其他社会经济变量如家庭规模对食品和营养需求的作用。方法这项研究使用最近的国家统计局农村调查数据,测度中国农村家庭的食物和营养的需求;线性近似几乎理想的需求系统(LA/AIDS)是用来估计价格和支出弹性,以及社会经济变量对粮食需求模式的影响。然后,使用一个基于广义工具变量方法分析营养需求的决定因素。结果结果表明,收入和其他社会经济变量对食物和营养的需求产生显著的影响。营养需求的支出弹性范围从蛋白质的0.34到胆固醇的1.10。结论这些结果反映食品组的高支出弹性几乎随着收入的升高而同步增加。 展开更多
关键词 线性近似几乎理想的需求系统(LA/AIDS) 食物需求 营养需求 非参数估计 工具变量
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