二维变系数线性微分系统的求解定理

给出二维变系数线性微分系统在已知某解的情形下求通解的公式,并直接应用此公式,导出几类二维变系数线性微分系统的通解公式.对理论和实际应用都是有益的.     

改革开放以来中国经济发展及1997—2010年经济发展预测(三)——中国地区经济发展的政策思路

预测“九五”至2010年中国地区经济发展,分析区域经济发展的两大特征,总结影响地区经济发展差别的基本规律,提出促进中国区域经济协调发展的政策选择。     

一种新的高分辨定位去噪方法

高分辨定位技术在近几年得到人们的广泛注意,在这方面的研究工作相当活跃。本文提出一种新的多目标阵列接收信号协方差矩阵的去噪方法,并对结果进行了计算机模拟。     

Bayesian adjustment for unidirectional misclassification in ordinal covariates

In this paper, we study the identification of Bayesian regression models, when an ordinal covariate is subject to unidirectional misclassification. Xia and Gustafson [Bayesian regression models adjusting for unidirectional covariate misclassification. Can J Stat. 2016;44(2):198–218] obtained model identifiability for non-binary regression models, when there is a binary covariate subject to unidirectional misclassification. In the current paper, we establish the moment identifiability of regression models for misclassified ordinal covariates with more than two categories, based on forms of observable moments. Computational studies are conducted that confirm the theoretical results. We apply the method to two datasets, one from the Medical Expenditure Panel Survey (MEPS), and the other from Translational Research Investigating Underlying Disparities in Acute Myocardial infarction Patients Health Status (TRIUMPH).     

在粤印度人状况初探

在粤印度人( 主要是生活在珠三角的印度人) 和整个在华的印度人一样,是一个非常独特的群体。他们以自己特有的方式生活、工作、学习或拓展自己的生意,一直保持着自己独特的生活方式和行为方式,坚持自己的文化特点,在各方面都显示出自己鲜明的特征。印度人在华的商业成功或在中国获得的机会吸引了更多的印度人来到中国。在华印度人,尤其是在粤印度人的人数将会不断增长,中、印通婚的人数也会不断地增加。这对中、印两国关系的方方面面均会产生重大的影响。     

唐国史中的史实遮蔽与形象建构——以玄宗先天二年政变书写为中心

先天二年政变是玄宗最终掌握最高权力的惊险一跃,而这一事件牵涉到玄宗与睿宗父子间激烈的权力争夺,因此唐代史官在国史中对这一事件进行了全面的讳饰。然而以张说所作的郭元振《行状》为切入点,结合相关文献记载,则可展示玄宗与睿宗及太平公主在政变之前激烈的政治较量、七月三日政变当天的整个过程,同时揭示政变后玄宗通过削弱政变功臣郭元振的权柄、最终掌握所有权力的真相。对于这场政变全方位的探索,显示唐代国史的书写通过遮蔽政治事件的关键性细节、重塑参与其中的政治人物,从而使史书记载最终符合其"政治正确"的逻辑。     

Diffusion Indexes With Sparse Loadings

The use of large-dimensional factor models in forecasting has received much attention in the literature with the consensus being that improvements on forecasts can be achieved when comparing with standard models. However, recent contributions in the literature have demonstrated that care needs to be taken when choosing which variables to include in the model. A number of different approaches to determining these variables have been put forward. These are, however, often based on ad hoc procedures or abandon the underlying theoretical factor model. In this article, we will take a different approach to the problem by using the least absolute shrinkage and selection operator (LASSO) as a variable selection method to choose between the possible variables and thus obtain sparse loadings from which factors or diffusion indexes can be formed. This allows us to build a more parsimonious factor model that is better suited for forecasting compared to the traditional principal components (PC) approach. We provide an asymptotic analysis of the estimator and illustrate its merits empirically in a forecasting experiment based on U.S. macroeconomic data. Overall we find that compared to PC we obtain improvements in forecasting accuracy and thus find it to be an important alternative to PC. Supplementary materials for this article are available online.     

Complete moment convergence and Lr convergence for asymptotically almost negatively associated random variables

In this paper, we investigate the complete moment convergence and L_r convergence for maximal partial sums of asymptotically almost negatively associated random variables under some general conditions. The results obtained in the paper generalize some corresponding ones for negatively associated random variables.     

Senior centres in the lives of older Americans: implications for Chinese older adults

As a critical community resource, the senior centre has provided older Americans with a wide array of recreational, nutritional, health, and social service programmes. Funding resources include the Older Americans Act allocations, local organisations and governments, national charities, voluntary associations, and religious associations. The types of programmes offered at a senior centre reflect two models: social agency model or voluntary organisation model. The five most popular programmes are nutrition, health and fitness, recreation, volunteering, and social services. Participation in senior centre activities has positive impacts on the overall well-being of older adult participants. With the rapid growth in the ageing population and improved life expectancy in China, senior centres may serve as a focal point for Chinese older adults by providing a broad spectrum of social services to enhance the well-being of community-dwelling older adults, to support their independence and dignity, and to facilitate ageing in place in later life.     

首都第二机场建设与航空人才需求调研

首都第二机场的建设已成定局,由此而引起的大量人才需求是各层次学校所关注的焦点。北京经济管理职业学院是否能抓住这一得天独厚的机遇,将是未来几年对北京经济管理职业学院的考验,因此根据近几年来对首都二机场建设的资料的收集和调研,了解了机场建设对航空人才的需求,为学院的发展提供了建设性的参考性意见。