设计过程中的工程数据库

本文从创造性设计过程的诸多方面叙述了建立工程数据库的重要性，指出了由于工程数据格式的不同，给数据通信带来的困难及解决办法。     

SOCIAL AND FAMILIAL ASPECTS OF ATTEMPTED AND COMPLETED SUICIDE OF YOUNG PEOPLE IN VICTORIA

A prospective study of youth suicide was carried out to determine the causes of the dramatic increase of suicide rates in males 15 to 25 years of age. Comprehensive information was collected through coronial enquiries on all 148 cases of completed youth suicide in Victoria during a 16 month period. Similar data were obtained through in-depth interviews of 105 hospitalised and 101 non-hospitalised attempters. In this paper only social and familial aspects of youth suicide are covered. Whilst the family setting of youth who attempted or completed suicide was similar to that of the general population, a higher proportion were homeless or living alone. Contrary to common assumptions, family relationships were much closer among completed than among attempted suicides. The unemployment rates were not higher than in all young people, and few subjects named unemployment as cause, but a relatively high number of them were neither studying nor looking for work. A high proportion of those who completed suicide had prior contact with the police. In conclusion, social factors do not significantly affect suicidal behaviour in young people.     

A note on generalized ridge estimators

It is shown that a necessary and sufficient condition derived by Farebrother (1984)for a generalized ridge estimator to dominate the ordinary least-squares estimator with respect to the mean-square-error-matrix criterion in the linear regression model admits a similar interpretation as the well known criterion of Toro-Viz-carrondo and Wallace (1968)for the dominance of a restricted least-squares estimator over the ordinary least-squares estimator. Two other properties of the generalized ridge estimators, referring to the concept of admissibility, are also pointed out.     

Bounds on the mean of the maximum of a number of normal random variables

A simple method producing lower and upper bounds on E max(X₁,...,X_n) is presented under assumption that the X_i's are independent normal random variables. Furthermore the upper bounds are determined when the X_i's are normal and positively correlated     

Fertility and social mobility

This article contains an analysis of part of the results of an inquiry into social mobility undertaken jointly by the Nuffield Research Unit of the London School of Economics and the Population Investigation Committee, in collaboration with the Ministry of Labour, based on nation-wide sample material collected by the Social Survey in England and Wales in 1949. Grateful acknowledgment is made to the Inter-Departmental Committee on Economic and Social Research for facilitating the collaboration with these government departments. In this paper, the relationship between fertility defined in terms of average family size of marriages of at least twenty years duration and social mobility is discussed. Two aspects of the latter phenomenon are discussed, namely, the position of sons on the social scale in relation to that of their fathers, and the change in the social status of a family in the period between the date of marriage and the date of the inquiry.

The conclusions reached stand in apparent contradiction to R. A. Fisher's ‘Theory of Infertility Selection’. It is shown that socially promoted families tend on the one hand to carry with them the family-building habits of the class of their origin, and, on the other, to acquire to some extent the fertility characteristics of the class into which they move.

The study of ‘personal’ social mobility throws some light on the question of the choice of the time-basis of socio-economic status allocation.