Joint impact of multiple observations on a subset of variables in multiple linear regression

In multiple linear regression analysis, each observation affects the fitted regression equation differently and has varying influences on the regression coefficients of the different variables. Chatterjee & Hadi (1988) have proposed some measures such as DSSE_ij (Impact on Residual Sum of Squares of simultaneously omitting the ith observation and the jth variable), F_j (Partial F-test for the jth variable) and F_j(i) (Partial F-test for the jth variable omitting the ith observation) to show the joint impact and the interrelationship that exists among a variable and an observation. In this paper we have proposed more extended form of those measures DSSE_IJ, F_J and F_J(I) to deal with the interrelationships that exist among the multiple observations and a subset of variables by monitoring the effects of the simultaneous omission of multiple variables and multiple observations.     

微机辅助设计机械产品装配图

本文提出一个在微机上设计机械产品装配图的方式。以Auto CAD为图形支持软件,利用其图形处理功能构成零件图子集,继而按装配要求形成草图,通过接口程序将图形信息转换成数字信息,求交、消隐后自动生成所需的产品装配图。     

The influence of peers and parents on youth life satisfaction in Hong Kong

This investigation attempts to measure the relative influence of peer and parental influence on the perceived life satisfaction of two groups of secondary students in Hong Kong. Data on 1906 students from 30 schools were collected through the use of a self-administered questionnaire. Respondents were asked to rate their level of satisfaction on 26 different domains of life on a seven-point scale, ranging from very satisfied to very dissatisfied, as well as their satisfaction with life in general. These 26 items were combined to form six summary indices of life satisfaction: school life, family life, acceptance by others, government, media, and living environment. Two independent variables were used in the analysis of life satisfaction: peer orientation, and parent orientation. Both are composite indices and measure the adolescent's attachment to and identification with his peers or parents. It was found that parent orientation is a better predictor of life satisfaction than peer orientation. Adolescents who are high on parent orientation are more satisfied with every domain of life. They are also more satisfied with life in general. The relationship between peer orientation and life satisfaction is not a clear-cut one. Adolescents with strong peer orientation are more satisfied with school, media, government, and acceptance by others, but are less satisfied with family. There is no significant relationship between peer orientation and environment. The younger adolescents in our sample tend to perceive a higher level of satisfaction than the older adolescents in every domain of life as well as life in general.     

Who Pays? Can We Pay Them Back?

This chapter is about a very old question that is thrown up again in discussion related to ANT. Do orders have necessary limits to what can belong to them? It is possible to read ANT as containing or demanding a moral commitment to the inclusion of the disenfranchised. It can often seem to be in the business of giving credit where credit is due, spreading recognition to even the most unexpected quarters. To sustain itself such a morality would depend on the possibility of infinite inclusion. By identifying this picture of 'belonging-by-assemblage' and its traditional counterpart 'belonging-by-banishment' and by finding both at play within ANT, the papers argues that ANT is an ethical rather than a moral enterprise, bringing the unanswered question of the nature of belonging to bear across domains, rather than approaching each domain with a 'cookie-cutter' moral formula. The disturbing 'unsecuring' of belonging that ANT involves continues within the philosophical tradition ANT trades on and contributes to in the form of an abiding controversy over the place of the natural world.     

Sex preference versus number preference: the case of Korea

The author argues that the effect of sex preference must be disentangled from the effect of number preference in Korea. This study tests--with hazard models--the effect of the number of previous children on the next birth according to the sex composition of previous children. Data were obtained from the 1974 Korean Fertility Survey. This paper also analyzes the timing of childbearing in recent periods in order to determine whether replacement-level fertility is temporary or permanent. The ideal number of children declined from 3.9 children in 1965 to 2.1 in 1991. The age-specific fertility rates for ages 20-24 years declined rapidly during the late 1980s. The fertility rates among women aged 25-29 years and 30-34 years increased during 1985-90. The proportion of fertility among women aged 20-29 years increased from 67.9% in 1975 to 86.6% in 1984. Women born in the late baby boom period of the late 1950s to mid-1960s reached prime reproductive age during the late 1980s and 1990s, but the crude birth rate remained about the same during 1985-92. A higher percentage of women (22.4%) born during 1955-59 remained single in 1990. During 1960-90, the percentage of women aged 20-24 years who were married declined. These trends indicate later age at childbearing and an explanation for the temporary nature of below-replacement fertility in the late 1980s. Korean women did not want to have more than 2 children, and the interval between first and second births increased since 1985. Among pregnancies of parity 2 conceived since 1985, over 90% of women with at least one son ended subsequent pregnancies by abortion compared to only 59% without sons. Hazard models of 1974 data reveal that son preference had an important effect on fertility. Fertility was higher among women with only daughters. Findings suggest that the value of sons must be measured at the societal and not at the individual level.     

The role of public health in population health

The role of public health is central in population health. What distinguishes public health from clinical medicine is that it's focus is on the entire population--not the individual patient. To achieve the goal of population health, healthy communities, or Healthy People 2000 requires physician leadership in medicine and public health at all levels--local, state, and national. The challenge is formidable, but the goals are attainable through strategies that focus on the goal of the common good and through collaboration of public health, medicine, and the community.     

动力减振器最优参数的非线性回归和若干问题

本文采用最优化方法求得考虑生系统阻尼的动力减振器最优参数集，并对此参数集进行非线性回归，得到了便于动力减振器最优设计的回归曲线族。本文还对现有的主系统无阻尼时动力减振器最优参数公式进行了讨论，指出了这些公式的局限性，并根据本文的结果给出了应用范围更广泛的改进公式。     

唐长安城胡人居所分布研究

唐王朝曾以其强大的经济、开明的政治以及包容的文化吸引了大规模的四夷入朝,开创了“九天阊阖开宫殿,万国衣冠拜冕旒”的盛景,其中以踏着丝绸之路前来的胡人为甚,胡人在唐长安城的活动极大地影响了唐王朝社会文化风尚.以现存文献、新出土墓志和唐诗为研究资料,探析唐长安城胡人居所的分布规律和迁移轨迹,探明唐前期形成了以西市为核心、以胡商为主体的街西胡人聚居区和以东市为核心、以入仕唐廷的官员为主体的街东胡人聚居区,其中街西胡人圈在唐长安城胡人圈中发挥着主导力量;“安史之乱”后,胡人大规模自西向东迁移,唐中后期街东胡人圈更具群体话语权;此外,以祆祠为中心的胡人居所辐射分布规律长期稳定,投射出胡文化巨大的凝聚力和向心力.     

城镇化视角下的土地流转影响因素研究——基于安徽5个市的农户调研数据

影响土地流转意愿的因素主要包括制度因素、经济因素、政策因素等.本文在城镇化背景下,基于农户角度,通过入户调查和logistic回归模型,研究家庭所在区域、城市购房打算等社会化因素,和土地收入、土地社会保障等土地功能因素对土地流转意愿产生的影响.研究结果表明,农户的社会化因素和土地功能因素对土地流转意愿均产生显著影响.