非线性中立型时滞微分方程解的振动性   总被引：1，自引：0，他引：1  

郭嫱  张炳根 《中国海洋大学学报(自然科学版)》2003,33(3):483-488

本文研究几类非线性中立型时滞微分方程解的振动性质 ,利用 Riccati不等式和某个不等式得到了保证方程振动的充分条件  相似文献   

求解变分不等式的Newton迭代的半局部收敛性分析     

王征宇  沈祖和 《华东地质学院学报》2003,26(2):159-162

分析了求解变分不等式Newton方法的半局部收敛性，建立了类似于Kantorovich定理的收敛性结果。该结果不仅为判断Newton方法的收敛性提供了可计算的充分条件，也给出了Newton方法的收敛域以及问题解的存在区域。同时，文章也得到了Newton方法的若干收敛性质，包含收敛阶以及可计算的误差估计式等。  相似文献   

1952~2003年我国区域经济发展不均衡的 长期变化态势   总被引：2，自引：1，他引：2  

郭腾云  徐勇 《地理科学进展》2005,24(1):21-30

文中分别利用Gini、GE等指数，以实际人均国内生产总值(GDP)为指标，详细考查了从1952~2003年，我国省市区间经济发展不均衡的变化态势及其在东部-内陆、南方-北方、高城镇化-低城镇化地区等方向上的变化。人均实际GDP的Gini、GE等指数显示，从1952~2003年，我国省级区域经济发展不均衡的总体态势是以较缓慢的速度逐步增加。具体的变化是，随着时间的推移区域经济不均衡呈周期性地上升、下降运动。就我国省市区经济发展不均衡在空间上的变化而言，一是在沿海-内陆和高城镇化-低城镇化方向上，分别在1990s中期和1980s中期以前，我国省市区经济不均衡主要表现为区域内部不均衡，但区域之间不均衡则不断增加，并逐步成为省市区经济不均衡主要部分；一是，在北方-南方方向上，我国省市区经济不均衡则是一直表现为区域内部不均衡，区域之间不均衡对省市区经济不均衡的贡献一直显得微不足道。  相似文献   

Covering Wildfires: Media Emphasis and Silence after the Carlton and Okanogan Complex Wildfires     

Alissa Cordner  Eliana Schwartz 《社会与自然资源》2019,32(5):489-507

  相似文献   

Robust H∞ control for aseismic structures with uncertainties in model parameters     

宋刚  林家浩  赵岩 《地震工程与工程振动(英文版)》2007,6(4):409-416

This paper presents a robust H∞ output feedback control approach for structural systems with uncertainties in model parameters by using available acceleration measurements and proposes conditions for the existence of such a robust output feedback controller. The uncertainties of structural stiffness, damping and mass parameters are assumed to be norm-bounded. The proposed control approach is formulated within the framework of linear matrix inequalities, for which existing convex optimization techniques, such as the LMI toolbox in MATLAB, can be used effectively and conveniently. To illustrate the effectiveness of the proposed robust H∞ strategy, a six-story building was subjected both to the 1940 El Centro earthquake record and to a suddenly applied Kanai-Tajimi filtered white noise random excitation. The results show that the proposed robust H∞ controller provides satisfactory results with or without variation of the structural stiffness, damping and mass parameters.  相似文献   

A century of inequality in England and Wales using standardized geographical units     

Ian Gregory  Daniel Dorling  & Humphrey Southall 《Area》2001,33(3):297-311

This paper analyses geographical trends in relative poverty in England and Wales over the last century by comparing key quantitative indicators from key dates. The comparison is made possible by interpolating all the datasets onto a single standardized geography. Results suggest rising inequality in spite of the decline in absolute poverty.  相似文献   

部分参数有非负约束平差模型的一种新算法   总被引：6，自引：1，他引：6  

宋迎春  朱建军  陈正阳  曾联斌 《武汉大学学报(信息科学版)》2007,32(10):883-887

研究了部分参数带有非负约束的平差模型,提出了一种新的处理部分参数附有非负约束的平差方法。该方法是先将非负约束的最小二乘问题转换成凸二次规划问题,然后求其最优解。通过模拟实例说明,此算法可以很好地应用于实际测量中的平差计算。  相似文献   

�����Բ���ʽԼ��ƽ��ģ�͵�һ������㷨   总被引：1，自引：0，他引：1  

宋迎春  刘杰  惠沈盈 《大地测量与地球动力学》2009,29(2):92-95

????Lemke???????в??????????????????????????????????в???????????С?????????????????ι滮?????????????ι滮??Kuhn??Tucker????????ι滮?????????LCP??????????Lemke?????????????????ò?????С????????????????????????????????á?  相似文献   

Ecological Modernization or Aristocratic Conservation? Exploring the Impact of Affluence on Carbon Emissions at the Local Level     

Andrew Pattison  Robert Habans  Matthew Thomas Clement 《社会与自然资源》2014,27(8):850-866

Social scientists have debated how affluence impacts carbon emissions at the national level. We conduct an exploratory study at the subnational level to expose another dimension of the affluence–emissions debate. Based on the notion of aristocratic conservation, we hypothesize that affluence is positively related to carbon emissions from consumption activities but negatively related to emissions from production activities. We test these hypotheses using county-level data in the United States for the year 2002. A spatial regression analysis demonstrates that median household income is positively associated with consumption-based emissions; nevertheless, we find evidence of an environmental inequality Kuznets curve in the relationship between median household income and production-based emissions. This finding suggests that the wealthiest counties are able to displace certain types of emissions, specifically those related to energy and industrial production. We discuss the theoretical and political implications of these results.  相似文献   

������ʽԼ���Ĵ�ز�������     

王乐洋  朱建军 《大地测量与地球动力学》2008,28(1):109-113

????Ω???????????????????????????????ò???????????????????????????????? ???????????????????????Ω?????????????????????????????????????????????????????????????÷????????????????????????????з??????????  相似文献