Generalized Steiner Problems and Other Variants

In this paper, we examine combinatorial optimization problems by considering the case where the set N (the ground set of elements) is expressed as a union of a finite number of m nonempty distinct subsets N ₁,...,N _m. The term we use is the generalized Steiner problems coined after the Generalized Traveling Salesman Problem. We have collected a short list of classical combinatorial optimization problems and we have recast each of these problems in this broader framework in an attempt to identify a linkage between these “generalized” problems. In the literature one finds generalized problems such as the Generalized Minimum Spanning Tree (GMST), Generalized Traveling Salesman Problem (GTSP) and Subset Bin-packing (SBP). Casting these problems into the new problem setting has important implications in terms of the time effort required to compute an optimal solution or a “good” solution to a problem. We examine questions like “is the GTSP “harder” than the TSP?” for a number of paradigmatic problems starting with “easy” problems such as the Minimal Spanning Tree, Assignment Problem, Chinese Postman, Two-machine Flow Shop, and followed by “hard” problems such as the Bin-packing, and the TSP.     

Using partially observed Markov processes to select optimal termination time of TV shows

This paper presents a method for optimal control of a running television show. The problem is formulated as a partially observed Markov decision process (POMDP). A show can be in a “good” state, i.e., it should be continued, or it can be in a “bad” state and therefore it should be changed. The ratings of a show are modeled as a stochastic process that depends on the show's state. An optimal rule for a continue/change decision, which maximizes the expected present value of profits from selling advertising time, is expressed in terms of the prior probability of the show being in the good state. The optimal rule depends on the size of the investment in changing a show, the difference in revenues between a “good” and a “bad” show and the number of time periods remaining until the end of the planning horizon. The application of the method is illustrated with simulated ratings as well as real data.     

Closeted cosmopolitans: Israeli gays between centre and periphery

Abstract In this article I present observations of gay life conducted in Tel Aviv in 1993 and 1998. Despite the invisibility of gay venues and the absence of gay political action, the men studied in 1993 (mostly professionals and artists) nevertheless did not express resentment or a wish to move to the Western havens of gay life with which they had been acquainted as frequent travellers. However, the gay scene in Tel Aviv seemed very different a few years later. A number of leading gay men made a successful claim for public recognition and a growing constituency of gay men and women came out to demonstrate for minority rights and a share of public space. Rather than relating the growth of gay empowerment solely to the idea of globalization or ‘postmodernism’, in this article I seek to consider the social context in which these worldwide influences take place. The introduction of two stages of observation displays the dynamic nature of social phenomena that ethnographers might often confront in their present‐day research projects.     

Incompletely Fractured Families

The modern family is increasingly isolated and increasingly unstable. As a result, family therapists are faced with a variety of problems in families where the parents have separated or divorced. One previously unrecognised problem occurs when the partners, although separated, covertly remain attached to the old alliance. Frequently a child, by becoming “ill”, remains as a bridge between them to prevent the final disintegration of the marriage bond. Three case histories are provided as an illustration of this phenomenon.     

Jewish-Arab Relations in Iraq: From the British Occupation to the Mass Exodus (1917–51)

From the establishment of the Iraqi polity under King Faisal I in 1921 the Jews were anxious to integrate into Muslim Arab society and become an integral part of it. However, with the end of the British Mandate in 1932 the Jews' relations with Arab society took a turn for the worst, reaching its climax in the 1941 pogrom. The struggle to determine the fate of Palestine and later the establishment of the state of Israel created an unbearable situation, which ultimately pushed the Jews out of Iraq, during the early 1950s. This study analyzes Jewish–Arab relations during that period, focused mainly on the circumstances which led to this change – from an attempt to integrate to Arab policy of controlled oppression.     

International migration and labor force participation of married women

A focal issue in international immigration research has been immigration adaptation and assimilation and especially absorption and integration of immigrants into labor force roles. Nevertheless, such research has largely been focused on immigrant men, neglecting the systematic examination of labor force participation among immigrant women. This research is focused on the correlates of economic activity among immigrant and native born Jewish, urban, married females aged 18–54 in Israel. The specific objectives of the investigation are: (1) the impact of education, socioeconomic status, familial child care burdens, and ethnic background on the economic activity of native-born and immigrant, married women; and (2) to evaluate the extent to which the above patterns vary by veterancy and age. The data for this analysis are drawn from Israel's quarterly labor force survey of 6,000 families for 1970 and 1971. Education, socioeconomic status, ethnic origin, and child care burden were all found to have some effect on women's labor force participation; however, the pattern of effect was different for younger and older women and varied by veterancy status. Indications can be found in the data that age at immigration, or in other words the point in the women's life cycle at which immigration occurs, makes a difference in the type and strength of effect of immigration on labor force participation.Requests for reprints should be directed to Moshe Hartman, Department of Sociology, Population Research Laboratory, Utah State University, Logan, Utah 84322.     

Arrow-Pratt Risk Aversion, Risk Premium and Decision Weights

This paper analyzes two issues: (a) the effect of decision-weights on risk premium, and (b) whether risk-aversion characterizes most investors. We theoretically show that cumulative prospect theory decision-weights systematically increase Arrow's risk premium, and may induce a positive risk premium even in the absence of risk-aversion. However, decision-weights may either increase or reduce Pratt's risk premium. We present three experiments revealing a striking result: a large proportion of the subjects' choices contradicts risk-aversion. This may be due to non-concave preferences, or to decision-weights. This result may have a dramatic impact on equilibrium models in economics and finance.