Lexicographic measurement of the information contained in opportunity sets

An individual who has to choose one item from an opportunity set or menu may lack complete information about the final consequences attached to her choice. This problem has been modeled by Bossert (2000) who introduces an axiomatic approach to the ranking of menus according to their informational content. We propose a different ranking based on the lexicographic ordering on the vectors of numbers of consequences for each item and characterize it axiomatically. Received: 12 June 1998/Accepted: 5 September 2000     

Network contact changes in early and later postseparation years

This study explains changes in contact frequency in relationships of the preseparation personal network in the early and later years after partners separate. The explanation includes general and separation-related characteristics of the network relationship and the individual. Personal interviews were conducted in three waves of a 12-year longitudinal study with 40 men and 64 women who separated in 1987 or 1988. Multilevel analyses on 1639 network ties showed that multiplex and kin relationships remained over the long term. Contact changes depended on network relationship characteristics, structural conditions, perceived restrictions, and alternative network relationships. Separation-related characteristics were more important in the early years, general characteristics in the later years after the separation.     

An inverse approach to convex ordered median problems in trees

The convex ordered median problem is a generalization of the median, the k-centrum or the center problem. The task of the associated inverse problem is to change edge lengths at minimum cost such that a given vertex becomes an optimal solution of the location problem, i.e., an ordered median. It is shown that the problem is NP-hard even if the underlying network is a tree and the ordered median problem is convex and either the vertex weights are all equal to 1 or the underlying problem is the k-centrum problem. For the special case of the inverse unit weight k-centrum problem a polynomial time algorithm is developed.     

Actual and de facto Childlessness in Old Age: Evidence and Implications from East Java,Indonesia

The demographic study of child supply has long concentrated on the implications of reproductive excess, rather than a lack of children. In recent years attention to population aging has begun to redress this emphasis, but even in aging research the comparative study of childlessness has a low profile. Data collected as part of anthropological and demographic research on aging in Indonesia are used to question current assumptions and to introduce issues and concepts that shed new light on current levels and experiences of childlessness. In our East Javanese study community 25 percent of the elderly have no living children, and another 15 percent have one child. Provincial and national data indicate that these findings are part of a wider pattern, corroborated by historical evidence from Indonesia, Europe, and populations elsewhere in the world. Analysis of the East Javanese data shows that childlessness is a composite category. Demographic childlessness occurs where a combination of proximate determinants (nuptiality, mortality, primary and pathological sterility) leads to no childbearing and child survival. De facto childlessness arises where there is a lack of support from any children. Actual childlessness aggregates demographic and de facto childlessness, net of adoption or remarriage where these provide alternative access to children. Analysis also takes into account the practices of patronage, charity, and kin support to assess the implications of childlessness in old age where state support is lacking.     

Old Dreams,New Means: an Exploration of Visions and Situated Knowledge in Information Technology

The aim of this article is to explore the tensions and ambivalences of new and old technology and political visions of keeping viable, quality care and services for elderly citizens through the use of new information technologies. The visions of politicians and social service managers of keeping alive the welfare state and retaining its ability to offer quality care and services for elderly citizens are compared with the experiences of female care assistants and their expectations of technology. A feminist figure — the cyborg — will be used in this exploration. We consider how care assistants are integrated in networks of socio‐technical relations between humans and non‐humans, and the extent to which gender or asymmetrical power relations between women and men intervene in their stories.     

Fault Trees vs. Event Trees in Reliability Analysis

Reliability analysis is the study of both the probability and the process of failure of a system. For that purpose, several tools are available, for example, fault trees, event trees, or the GO technique. These tools are often complementary and address different aspects of the questions. Experience shows that there is sometimes confusion between two of these methods: fault trees and event trees. Sometimes identified as equivalent, they, in fact, serve different purposes. Fault trees lay out relationships among events. Event trees lay out sequences of events linked by conditional probabilities. At least in theory, event trees can handle better notions of continuity (logical, temporal, and physical), whereas fault trees are most powerful in identifying and simplifying failure scenarios. Different characteristics of the system in question (e.g., a dam or a nuclear reactor) may guide the choice between fault trees, event trees, or a combination of the two. Some elements of this choice are examined, and observations are made about the relative capabilities of the two methods.