Selection of regress or va riables when E(Y) is an unknown honlinear function

We consider the problem of deciding which of a set of p independent variables x₁ X₂J x_s we are to regard as being functionally involved in the mean of a dependent normal random variable Y and estimating E( Y) in terms of the chosen x's. This mean is an unknown function (assumed to be doubly differentiable) of some or all of the x's, so that the problem is of wide relevance. We approximate to the hypersurface in two different ways, and select within each approximation:

(a)For the situation where the mean of Y is assumed to be a linear function of the x's, we use ono of the optimum methods of selection.

(b)More generally, in the space of the X's the function will be approximately linear in a relatively small region. Accordingly this p-dimensional space is subdivided into smaller regions by a clustering procedure, and a hyperplane if fitted with in each region to aproximate to the unknown responce surface.An adaption of an optimum-regressor-selection procedure is then used to assist in the selection of the regressors

Approximate F tests are given to choose between models, including deciding how many x's to retain. Alternatively: the application of Akaike's Extended Maximum Likelihood Principle provides another way of choosing between the models and of selecting regressor variables. The methods are applied to data on glass manufacture.     

利用空气幕提高抽油烟机抽吸效率

油烟是室内空气的主要污染源,控制其扩散是抽油烟机实现高效率捕集油烟的有效手段。采用在集气罩上加装空气幕的技术措施,能够阻止油烟蔓延,保持室内外压力平衡。从提高空气射流的动力性能和阻断能力着手,开发稳定性和封闭性较好的空气幕应用于抽油烟机,不仅提高了工作效率,而且节能效果显著。     

Mediating self‐hood: exploring the construction and maintenance of identity by mothers of children labeled with autism spectrum disorder

Based on the findings of a qualitative study, this article describes how mothers of children labeled with autism spectrum disorder (ASD) mediate for their children in interactions with those who are unfamiliar with ASD. Data were collected through in‐depth interviews and participant observations. Findings indicate that mothers mediate for their children because they perceive hostility and lack of accommodation for their children on the part of unfamiliars. As they mediate, mothers attempt to construct and maintain positive identities for their children by explaining and reframing their children’s behaviors to influence the interpretations and responses of unfamiliars. I argue that in these interactions mothers function as proxy selves for their children because they are attempting to influence the perceptions others develop of their children, thus shaping their children’s social identity in the process. The findings of this study demonstrate the active, interpretive role that many mothers of children with autism play as they continually sort and assess information in order to determine what is in the best interests of their children. Further, the findings presented here demonstrate the social nature of self‐hood and identity, that all people involve others in the performance of their self‐hood. In this way and others, people labeled with ASD have much in common with those considered normal.     

吸气罩流场的分区边界积分法求解

将吸气罩流场计算区域分成两个子区域，分别推导出各子区域边界积分方程，并将各子区域方程组合成一个方程，利用边界元法进行求解．