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11.
以泰州某大跨度连续梁桥的静动载试验为例,建立ANSYS和桥梁博士模型进行静动力有限元数值计算。将试验结果与模型计算值进行比较,试验结果表明,该桥结构刚度和承载能力满足设计要求。  相似文献   
12.
ABSTRACT

The varying-coefficient single-index model (VCSIM) is a very general and flexible tool for exploring the relationship between a response variable and a set of predictors. Popular special cases include single-index models and varying-coefficient models. In order to estimate the index-coefficient and the non parametric varying-coefficients in the VCSIM, we propose a two-stage composite quantile regression estimation procedure, which integrates the local linear smoothing method and the information of quantile regressions at a number of conditional quantiles of the response variable. We establish the asymptotic properties of the proposed estimators for the index-coefficient and varying-coefficients when the error is heterogeneous. When compared with the existing mean-regression-based estimation method, our simulation results indicate that our proposed method has comparable performance for normal error and is more robust for error with outliers or heavy tail. We illustrate our methodologies with a real example.  相似文献   
13.
高新才  赵玲 《西北人口》2010,31(3):120-123,F0003
人口承载力的研究对象是由若干个内部关系错综复杂、相互之间联系紧密的子系统所组成的“自然-经济-社会”复合巨系统,本文运用系统动力学建立复合模型仿真模拟预测黑河流域人口承载力状况.并建立黑河流域人口承载力的预警指标体系。复合模型预测数据显示,黑河流域人口承载力呈超载状态.而预警目标值Z=0.979〈1,说明该区没有实现持续发展,乃“磊、乙三个指标小于1,说明黑河流域生态环境和固定资产投资占比是影响黑河流域发展的主要因素。  相似文献   
14.
本文以我国股票市场为研究对象,选用2007年1月—2010年12月的月度时间序列数据,分别进行了单位根检验和回归分析,结果表明:在该段时间内,CAPM在我国的股票市场是有效的,并且个股的收益率与市场组合收益率呈正相关关系,通过对截距项的分析,比较了各个股票预期与实际收益率的差别,对投资者具有一定的指导意义。  相似文献   
15.
该文考虑的是具有分布控制的Timoshenko梁系统的精确能控性.用谱分解方法建立了保守系统的正反向能量不等式,证明了在通常的能量空间中该系统是精确能控的.  相似文献   
16.
This article defines Active Citizenship within a European context as a broad range of value based participation. It develops a framework for measuring this phenomenon which combines the four dimensions of Protest and Social Change, Community Life, Representative Democracy and Democratic values. The European Social Survey 2002 is used to populate the framework as this survey provided the best data coverage available and covered 19 European Countries. In total 61 indicators were selected. A composite indicator (CI), The Active Citizenship Composite Indicator (ACCI), is built using the framework provided and using experts’ weights. In addition, the robustness of the results is tested using sensitivity analysis. The limitations to the ACCI are explained in terms of the limitation of the data availability in particular concerning the new forms of participation and less organised forms of participation. Nevertheless, ACCI proved to be statistically robust and reliable and proved to be a useful tool for monitoring levels of citizenship in Europe. The results of ACCI exhibit interesting and quite distinct regional patterns. The results showed that the Nordic countries, and in particular Sweden, have the highest rate of Active Citizenship, followed by Central Europe and Anglo-Saxon countries. Mediterranean countries are next followed by Eastern European countries that close the ranking.
Massimiliano MascheriniEmail:
  相似文献   
17.
In this paper, we propose a new partial correlation, the so-called composite quantile partial correlation, to measure the relationship of two variables given other variables. We further use this correlation to screen variables in ultrahigh-dimensional varying coefficient models. Our proposed method is fast and robust against outliers and can be efficiently employed in both single index variable and multiple index variable varying coefficient models. Numerical results indicate the preference of our proposed method.  相似文献   
18.
The composite quantile regression (CQR) has been developed for the robust and efficient estimation of regression coefficients in a liner regression model. By employing the idea of the CQR, we propose a new regression method, called composite kernel quantile regression (CKQR), which uses the sum of multiple check functions as a loss in reproducing kernel Hilbert spaces for the robust estimation of a nonlinear regression function. The numerical results demonstrate the usefulness of the proposed CKQR in estimating both conditional nonlinear mean and quantile functions.  相似文献   
19.
The traditional Cobb–Douglas production function uses the compact mathematical form to describe the relationship between the production results and production factors in the production technology process. However, in macro-economic production, multi-structured production exists universally. In order to better demonstrate such input–output relation, a composite production function model is proposed in this article. In aspect of model parameter estimation, artificial fish swarm algorithm is applied. The algorithm has satisfactory performance in overcoming local extreme value and acquiring global extreme value. Moreover, realization of the algorithm does not need the gradient value of the objective function. For this reason, it is adaptive to searching space. Through the improved artificial fish swarm algorithm, convergence rate and precision are both considerably improved. In aspect of model application, the composite production function model is mainly used to calculate economic growth factor contribution rate. In this article, a relatively more accurate calculating method is proposed. In the end, empirical analysis on economic growth contribution rate of China is implemented.  相似文献   
20.
钛合金电子束焊接接头疲劳试验数据统计分析   总被引:3,自引:0,他引:3  
本文利用国际焊接学会推荐的统计方法,对BT20钛合金电子束焊接接头焊态和焊后电子束局部热处理两种试样的疲劳试验结果进行了统计处理与分析.结果表明:对于BT20钛合金母材和电子束对接接头可以按铝合金参考FAT80级S—N曲线进行疲劳设计.建议在对BT20薄板进行电子束焊接和电子束局部热处理时应采取必要措施,以保证将焊接变形控制到最小程度,从而提高其疲劳强度.  相似文献   
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