Inference in hybrid Bayesian networks using dynamic discretization

We consider approximate inference in hybrid Bayesian Networks (BNs) and present a new iterative algorithm that efficiently combines dynamic discretization with robust propagation algorithms on junction trees. Our approach offers a significant extension to Bayesian Network theory and practice by offering a flexible way of modeling continuous nodes in BNs conditioned on complex configurations of evidence and intermixed with discrete nodes as both parents and children of continuous nodes. Our algorithm is implemented in a commercial Bayesian Network software package, AgenaRisk, which allows model construction and testing to be carried out easily. The results from the empirical trials clearly show how our software can deal effectively with different type of hybrid models containing elements of expert judgment as well as statistical inference. In particular, we show how the rapid convergence of the algorithm towards zones of high probability density, make robust inference analysis possible even in situations where, due to the lack of information in both prior and data, robust sampling becomes unfeasible.     

Disability and identity: the challenge of epilepsy

Through examining the case of people with epilepsy (which, as we demonstrate, has an ambiguous status in relation to both popular and academic conceptions of disability) we explore the fluid, negotiable and contingent nature of identity and, in particular, the identification as ‘disabled’. Disability, we argue, cannot be reduced to either biology or social oppression, or even primarily to biological or social factors: it is the outcome of a complex interaction between a multiplicity of factors – biological, environmental, social, psychological, cultural and political – which will interact and be experienced differently by different people, at different times and in different situations. Rather than conceiving of disability in ‘all or nothing’ terms and of differing explanations as competing and mutually exclusive, it would be more productive to see them as partial and potentially complementary contributions to the better understanding of a complex and multifarious reality.     

简论女丹修炼的特殊机理

女丹功法,又称"坤诀",是指妇女修炼内丹之法。女性之内丹修炼活动虽可追溯至唐代,但其学说成熟则较晚。男女两性存在着生理和心理上的差异,因此,内丹修炼在功法和步骤上也应有所区别。传统中医学原理可以帮助我们阐释女丹修炼程序及"斩赤龙"的特殊机理及其意义。女丹功法的关键步骤为"太阴炼形"之术,其关窍为膻中穴和血海;"阳神出壳"是女子丹功炼至最高层次时所出现的现象,炼功者此时要格外谨慎。     

The Cost of High Unemployment

In response to R. A. B. Leaper's challenge in the last issue of this journal we present a report which we have just prepared for the BBC North-East. We believe that a better understanding of the costs of high unemployment to the country is needed to inform decisions on how much we can afford to pay to tackle the problem. In the final section of the paper we show how this evidence can be of value in costing policy options.
The last detailed costings of unemployment were published in 1982 for the financial year 1981/82. In February 1982 it appears that a political decision was taken not to publish the latest Treasury estimate updating their 1981 calculations. Since then numerous parliamentary questions on the subject have received very limited answers disputing the validity of the whole exercise.     

Social work in mental health services: A survey of the field

Abstract

A survey of social workers employed in mental health services was conducted in Victoria in mid-1997. Approximately 300 social workers were identified as working in the sector. About half were employed in adult clinical services, 23% in psychiatric disability services, 12.4% in Child and Adolescent Mental Health Services, and the rest in a range of other services. More than 90% worked in a community based service or team. The number of entry-level (SW I) positions in clinical services was found to have declined over the last ten years from 61 to 14, resulting in a lack of opportunities for social workers to gain experience in base grade positions, and difficulty in recruiting to SW II positions. Major issues of concern reported by social workers included: the lack of accommodation and other community resources for consumers; diminished opportunities for professional development, supervision, and discipline-specific training; lack of professional recognition; increasing workloads; and organisational emphasis on throughput rather than quality.     

A Tale of Two Counties: Natives’ Opinions Toward Immigration in North Carolina1

This article compares native residents’ opinions and perceptions regarding immigration using a representative survey from a pair of matched North Carolina counties – one that experienced recent growth of its foreign-born population and one that did not. Drawing from several theoretical perspectives, including group threat, contact theory, and symbolic politics, we formulate and empirically evaluate several hypotheses. Results provide limited evidence that competition and threat influence formation of opinions about immigration, with modest support for claims that parents with school-aged children harbor more negative views of immigration than their childless counterparts. Except for residents in precarious economic situations, these negative opinions appear unrelated to the immigrant composition of the community. Claims that the media promotes negative views of immigration receive limited support, but this relationship is unrelated to the volume of local immigration. Finally, sustained contacts with foreign-born residents outside work environments are associated with positive views of immigration, but superficial contacts appear to be conducive to anti-immigration sentiments. Political orientation, educational attainment, and indicators of respondents’ tolerance for diversity explain most of the difference between the two counties in overall support for immigration.     

Non-Gaussian Ornstein–Uhlenbeck-based models and some of their uses in financial economics

Non-Gaussian processes of Ornstein–Uhlenbeck (OU) type offer the possibility of capturing important distributional deviations from Gaussianity and for flexible modelling of dependence structures. This paper develops this potential, drawing on and extending powerful results from probability theory for applications in statistical analysis. Their power is illustrated by a sustained application of OU processes within the context of finance and econometrics. We construct continuous time stochastic volatility models for financial assets where the volatility processes are superpositions of positive OU processes, and we study these models in relation to financial data and theory.     

A general method of constructing E(s2)-optimal supersaturated designs

There has been much recent interest in supersaturated designs and their application in factor screening experiments. Supersaturated designs have mainly been constructed by using the E ( s ²)-optimality criterion originally proposed by Booth and Cox in 1962. However, until now E ( s ²)-optimal designs have only been established with certainty for n experimental runs when the number of factors m is a multiple of n-1 , and in adjacent cases where m = q ( n -1) + r (| r | 2, q an integer). A method of constructing E ( s ²)-optimal designs is presented which allows a reasonably complete solution to be found for various numbers of runs n including n ,=8 12, 16, 20, 24, 32, 40, 48, 64.