A spanning heuristic for the unordered and ordered matching identification problem

The matching identification problem (MIP) is a combinatoric search problem related to the fields of learning from examples, boolean functions, and knowledge acquisition. The MIP involves identifying a single “goal” item from a large set of items. Because there is commonly a cost associated with evaluating each guess, the goal item should be identified in as few guesses as possible. As in most search problems, the items have a similar structure, which allows an evaluation of each guessed item. In other words, each guessed item elicits partial information about the goal item, i.e. how similar the guess is to the goal. With this information the goal is more quickly identified.The unordered MIP has been studied by Mehrez and Steinberg (ORSA J. Comput. 7 (1995) 211) in which they proposed two different types of algorithms. The purpose of the present paper is to suggest an improved Spanning Heuristic algorithm. Its improvement increases as the problem size increases. Further results and comparisons are derived for the unordered and ordered cases.This research shows that when the search space is very large, it is better to inquire from items that are known not to be the goal (they have been ruled out by previous guesses), for the purpose of acquiring more information about the goal. As the search space is narrowed, it is better to guess items that have not been ruled out.     

Complexity and Competition

Extensive‐form market games typically have a large number of noncompetitive equilibria. In this paper, we argue that the complexity of noncompetitive behavior provides a justification for competitive equilibrium in the sense that if rational agents have an aversion to complexity (at the margin), then maximizing behavior will result in simple behavioral rules and hence in a competitive outcome. For this purpose, we use a class of extensive‐form dynamic matching and bargaining games with a finite number of agents. In particular, we consider markets with heterogeneous buyers and sellers and deterministic, exogenous, sequential matching rules, although the results can be extended to other matching processes. If the complexity costs of implementing strategies enter players’ preferences lexicographically with the standard payoff, then every equilibrium strategy profile induces a competitive outcome.     

A Screening Methodology for the Identification and Ranking of Infrastructure Vulnerabilities Due to Terrorism

The extreme importance of critical infrastructures to modern society is widely recognized. These infrastructures are complex and interdependent. Protecting the critical infrastructures from terrorism presents an enormous challenge. Recognizing that society cannot afford the costs associated with absolute protection, it is necessary to identify and prioritize the vulnerabilities in these infrastructures. This article presents a methodology for the identification and prioritization of vulnerabilities in infrastructures. We model the infrastructures as interconnected digraphs and employ graph theory to identify the candidate vulnerable scenarios. These scenarios are screened for the susceptibility of their elements to a terrorist attack, and a prioritized list of vulnerabilities is produced. The prioritization methodology is based on multiattribute utility theory. The impact of losing infrastructure services is evaluated using a value tree that reflects the perceptions and values of the decisionmaker and the relevant stakeholders. These results, which are conditional on a specified threat, are provided to the decisionmaker for use in risk management. The methodology is illustrated through the presentation of a portion of the analysis conducted on the campus of the Massachusetts Institute of Technology.     

Adoption Issues: Preparation of Psychologists and an Evaluation of the Need for Continuing Education

This study is an investigation of the level of preparation psychologists have in dealing with adoption issues and an assessment of the need for further education in treating triad members. A questionnaire was mailed to 497 psychologists randomly selected from the National Register of Health Service Providers in Psychology who received doctoral degrees between the years of 1990 and 1996. Two hundred and ten psychologists, all of whom were currently treating clients, participated in the study. Psychologists completed a Likert rating of their sense of preparation to treat triad members. The largest group (51%) rated themselves as Somewhat prepared, with the second largest group (23%) rating themselves as Not very prepared. Ninety percent reported they needed more education in adoption, and 81% reported interest in taking a continuing education course in adoption. Of the 210 participants, only 67 reported taking courses that dealt with adoption as part of their formal education. Of those psychologists who reported taking courses that involved adoption, they averaged only 1.3 courses during their undergraduate education, and 1.5 courses during graduate education, while the remaining 143 psychologists received no education in this area. When one considers the proportion of triad members seen clinically, this study suggests psychologists need more education and background information about the effects of the adoption process.     

Why are residential and school moves associated with poor school performance?

Most research on residential mobility has documented a clear pattern: Residential and school moves are associated with poor academic performance. Explanations for this relationship, however, remain speculative. Some researchers argue that moving affects social relationships that are important to academic achievement. But the association between moving and school performance may be spurious; the negative correlation may be a function of other characteristics of people who move often. We offer several conceptual and analytical refinements to these ideas, allowing us to produce more precise tests than past researchers. Using longitudinal data, we find that differences in achievement between movers and nonmovers are partially a result of declines in social relationships experienced by students who move. Most of the negative effect of moving, however, is due to preexisting differences between the two groups.     

Kinship patterns and household composition: Older unmarried Hungarian women, 1984

Household composition of older unmarried women in Hungary is analyzed using data from the 1984 microcensus. The principal determinants of household composition investigated are kin availability — the number of living children, siblings, and parents — health status, marital status, age, and income. A multinomial logit model distinguishing among five household types reveals that number of children, severe disabilities, age and income are all strongly related to household composition. Trends in fertility and mortality patterns suggest that kinship patterns will change in coming years; these results imply that household composition will, in turn, change as well.     

Statistical and Historical Analyses of Nations Which Deviate From the Size-Density Law

We examine nations which deviate significantly from the ?2/3 sizedensity slope previously observed for the aggregated political subdivisions of 98 modern nations and previously derived from the theory of timeminimization. We correct Stephan’s original list of deviant nations, demonstrate that all slopes more negative than ?2/3 were due to the erroneous inclusion of cities in the original data sets, develop a theory to account for the less negative deviant slopes, and test the theory both through statistical manipulation of current data and through analysis of available historical data.     

Characteristics of gay, lesbian, and bisexual Asians, Asian Americans, and immigrants from Asia to the USA

An exploratory study of self-identified lesbian, gay, and bisexual Asians and Asian Americans surveyed respondents (60 women and 254 men) using a questionnaire in four languages from nineteen different sources in Korea, Japan, China, and the US. Respondents were compared in terms of country of residence, whether they immigrated to the US, having a same-sex lover, living with the lover, being open about their sexual orientation to the family, and age. Respondents in the US were generally more open about their sexual orientation. Openness to the family was related to other variables suggesting an affirmative lesbian, gay, or bisexual identity.     

An integrative intervention for promoting recovery from extramarital affairs

The discovery or disclosure of an extramarital affair can have a devastating impact on partners, both individually and on the relationships. Research suggests that affairs occur relatively frequently in relationships and are a common presenting problem in couple therapy. However, despite their prevalence, there is little empirical treatment research in this area, and most therapists describe this problem as one of the more difficult to treat. In this study, we used a replicated case-study design to explore the efficacy of an integrative treatment designed to help couples recover from an affair. Six couples entered and completed treatment. The majority of these couples were less emotionally or maritally distressed at the end of treatment, and the injured partners reported greater forgiveness regarding the affair. Details of the intervention, suggested adaptations of the treatment, and areas for future research are discussed.