A rare event approach to high-dimensional approximate Bayesian computation

Approximate Bayesian computation (ABC) methods permit approximate inference for intractable likelihoods when it is possible to simulate from the model. However, they perform poorly for high-dimensional data and in practice must usually be used in conjunction with dimension reduction methods, resulting in a loss of accuracy which is hard to quantify or control. We propose a new ABC method for high-dimensional data based on rare event methods which we refer to as RE-ABC. This uses a latent variable representation of the model. For a given parameter value, we estimate the probability of the rare event that the latent variables correspond to data roughly consistent with the observations. This is performed using sequential Monte Carlo and slice sampling to systematically search the space of latent variables. In contrast, standard ABC can be viewed as using a more naive Monte Carlo estimate. We use our rare event probability estimator as a likelihood estimate within the pseudo-marginal Metropolis–Hastings algorithm for parameter inference. We provide asymptotics showing that RE-ABC has a lower computational cost for high-dimensional data than standard ABC methods. We also illustrate our approach empirically, on a Gaussian distribution and an application in infectious disease modelling.     

Decision Support for Airline Schedule Planning

Since the 1950s, the operations research community has developed a large number of computer models to aid in the solution of airline scheduling problems. One notable characteristic of these contributions is that each algorithm was developed with its own input and output structures, user interface, and hardware and software requirements. The result is that many of these contributions are under-utilized because they are cumbersome to use, not integrated with the other airline's systems, and not connected across all functions of the airline (from planning to operations control). What was needed to make these contributions effective was a scheduling environment with a systematic interaction between the human, standardized databases across all functions of the airline, powerful desktop workstations for decision support, a standardized interactive graphical user interface for schedule editing, and the operations research techniques for optimization. This paper reports on the application of the integration of computer science and operations research in a decision support system for airline schedule planning. The application integrates a graphical user interface and the database with the schedule optimization algorithms.     

Civility: A Contemporary Context for a Meaningful Historical Concept

An overview of the relationship between social structure and social order is employed to highlight the importance of the civility concept to civic society. In discussing these issues, the author provides a brief historical and a contemporary context for assessing the civility concept. This assessment draws on an eclectic literature that addresses the relationship among civility, socialization, and learning, the role of education in the civility process, the changing emphasis of higher education, the culture of individualism, and technology. The author concludes with a brief discussion of culture and the future of civility.
The problem of order arises out of the dual circumstance that human beings have limited (though not nonexistent) capacities for sympathy with their fellows and that they inhabit an environment that fails to provide them with sufficient resources to satisfy fully the needs of all of them. The problem of order is therefore rooted in inescapable conflict between the interests and desires of individuals and the requirements of society: to wit, the pacification of violent strife among men and the secure establishment of cooperative social relations making possible the pursuit of collective goals. (Wrong 1994, p. 36)     

Privacy and profitability in the technological workplace

VI. Conclusion New communications technology inevitably creates new problems of privacy; think of the introduction of telephones (when party lines were common), faxes (which can lie in a room accessible by many people before reaching the addressee), and cell phones (which allow bystanders to hear one side of seemingly confidential communications). Computer monitoring of performance, e-mails, and Internet access are no different in this regard. Each development requires adjustments. I thank Holly Newell of the University of South Carolina Law School Class of 2004 for her diligent research on and editorial assistance with this article.     

Is comprehensive education really free?: a case-study of the effects of secondary school admissions policies on house prices in one local area

Summary. The paper reports on a study that tests the anecdotal hypothesis that parents are willing to pay a premium to secure places for their children in popular and oversubscribed comprehensive schools. Since many local education authorities use admissions policies that are based on catchment areas and places in popular schools are very difficult to obtain from outside these areas—but very easy from within them—parents have an incentive to move house for the sake of their children's education. This would be expected to be reflected in house prices. The study uses a cross-sectional sample based on two popular schools in one local education authority area, Coventry. Differences in quality of housing are dealt with by using the technique of hedonic regression and differences in location by sample selection within a block sample design. The sample was chosen from a limited number of locations spanning different catchment areas to reduce both observable and unobservable variability in nuisance effects while maximizing the variation in catchment areas. The results suggest that there are strong school catchment area effects. For one of the two popular schools we find a 20% premium and for the other a 16% premium on house prices ceteris paribus .     

Pathways to recovery after substance abuse treatment: leaving a life of crime behind

Changes in criminal activity following substance abuse treatment were examined among 941 individuals. The estimated cost to society of crimes committed in the 6 months prior to intake was used to classify participants into three groups: no-, low-, and high-cost. Logistic regression was used to predict criminal activity at 6 and 24 months following intake as a function of (a) intake status, (b) treatment, and (c) outcome status and changes. The three groups varied significantly at intake and what predicted subsequent criminal activity. Treatment effects on criminal activity were mediated by the extent to which treatment reduced substance use. Outcomes were also predicted by other factors (e.g. housing, employment, medical problems, psychological distress, and social support). The results support the need for multidimensional assessments for predicting the risk of illegal activity, the need for reassessments following treatment, and the value of addressing other problems in reducing subsequent criminal activity.     

Military leadership: A context specific review

The purpose of this article is to review the literature on military leadership and highlight research opportunities for leadership scholars. The review uses a context specific approach and turns to a simplified version of Hunt's (Hunt, J. G. (1991). Leadership: A new synthesis. Newbury Park, CA: Sage) extended multilevel leadership model as a template to examine the many facets of military leadership. The military leadership literature is stratified into the systems, organizational, and direct levels of leadership with an examination of studies on the critical tasks and individual capabilities required at each level. Additionally, studies on organizational culture and effectiveness at each level are addressed. The article emphasizes that the military is undergoing substantial change as it adjusts to the changing nature of war and a fluid world situation. Based on trends in the military, the review concludes with several general recommendations for future research.