Semiring induced valuation algebras: Exact and approximate local computation algorithms

Local computation in join trees or acyclic hypertrees has been shown to be linked to a particular algebraic structure, called valuation algebra.There are many models of this algebraic structure ranging from probability theory to numerical analysis, relational databases and various classical and non-classical logics. It turns out that many interesting models of valuation algebras may be derived from semiring valued mappings. In this paper we study how valuation algebras are induced by semirings and how the structure of the valuation algebra is related to the algebraic structure of the semiring. In particular, c-semirings with idempotent multiplication induce idempotent valuation algebras and therefore permit particularly efficient architectures for local computation. Also important are semirings whose multiplicative semigroup is embedded in a union of groups. They induce valuation algebras with a partially defined division. For these valuation algebras, the well-known architectures for Bayesian networks apply. We also extend the general computational framework to allow derivation of bounds and approximations, for when exact computation is not feasible.

Cognitive functioning in subjects with recent-onset psychosis from a low-middle-income environment: Multiple-domain deficits and longitudinal evaluation

Cognitive deficits are a key feature of recent-onset psychosis, but there is no consensus on whether such deficits are generalized or confined to specific domains. Besides, it is unclear whether cognitive deficits: a) are found in psychotic patients in samples from outside high-income countries; and b) whether they progress uniformly over time in schizophrenia and affective psychoses. We applied 12 tests organized into eight cognitive domains, comparing psychosis patients (n = 56, time from initial contact = 677.95+/-183.27 days) versus healthy controls (n = 70) recruited from the same area of Sao Paulo, Brazil. Longitudinal comparisons (digit span and verbal fluency) were conducted between a previous assessment of the subjects carried out at their psychosis onset, and the current follow-up evaluation. Psychosis patients differed significantly from controls on five domains, most prominently on verbal memory. Cognitive deficits remained detectable in separate comparisons of the schizophrenia subgroup and, to a lesser extent, the affective psychosis subjects against controls. Longitudinal comparisons indicated significant improvement in schizophrenia, affective psychoses, and control subjects, with no significant group-by-time interactions. Our results reinforce the view that there are generalized cognitive deficits in association with recent-onset psychoses, particularly of non-affective nature, which persist over time. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Income, deprivation and economic stress in the enlarged European Union

At risk of poverty indicators based on relative income measures suggest that within the enlarged EU societies located at quite different points on a continuum of affluence have similar levels of poverty. Substantial differences in levels of income between societies do not in themselves invalidate this approach. However, the relative income approach fails to capture the fact that, if countries are grouped in terms of level of GDP, between economic cluster differences in life-style deprivation are sharper at lower income levels. Support for the argument relating to restricted reference groups is found in relation to the contrast between the twelve most affluent EU countries and all others. The limitations of relative income poverty lines have little to do with the process of enlargement as such. Instead the major problem involves the weak association between income and deprivation in the more affluent countries. However, as a consequence of such difficulties, such indicators do not provide entirely meaningful comparisons of levels of disadvantage across economic clusters. The current analysis, rather than supporting the alternative of a focus on absolute income or an EU wide poverty line, suggests that we should take the argument for adopting a multidimensional approach to the measurement of poverty more seriously.

Welfare regimes and household income packaging in the European Union

This paper uses harmonized data for the member states of the European Union to analyse household income packaging from a 'welfare regimes' perspective. Using data from the third wave of the ECHP, it looks at how the role of welfare transfers in the income package varies across countries and welfare regimes, and assesses whether this is consistent with the predictions of welfare regime theory, having first elaborated some specific hypotheses in that regard. It finds that when one focuses on averages across countries categorized into regimes, many of these hypotheses about the role of transfers are in broad terms borne out by the evidence. However, when one focuses on individual countries rather than regime averages the picture is a good deal more complex and consistency with the range of hypotheses more limited. It is essential that this variation across countries is taken into account in interpreting and using welfare regime theory and typologies.

Understanding the mismatch between income poverty and deprivation: A dynamic comparative analysis

In this paper we seek to shed light on the mismatch between income poverty and deprivation through a comparative and dynamic analysis of both forms of disadvantage. By extending analysis over five waves of the ECHP we are able to take into account the key dimensions characterizing poverty profiles overtime. Our conclusions turn out to be remarkably stable across countries. While persistent income poverty measures are systematically related to both cross-sectional and longitudinal measures of deprivation, the scale of mismatch is no less at the latter than at the former level. There is some evidence that although rates of volatility for income and deprivation measures are roughly similar, the processes of change themselves are somewhat different. Further light is shed on the underlying processes by cross-classifying the forms of deprivation. Those exposed to both types of deprivation are differentiated from others in terms of need and resource variables. Conclusions relating to the socio-demographic influences on risk levels are influenced by choice and combination of indicators. The results of our analysis confirm the need to devote considerably more attention than heretofore to the analysis of multi-dimensional poverty dynamics.

Persistent income poverty and deprivation in the European Union: An analysis of the first three waves of the European Community Household Panel

Poverty research has increasingly focused on persistent income poverty, both as a crucial social indicator and as a target for policy intervention. Such an approach can lead to an identification of a sub-set of poor individuals facing particularly adverse circumstances and/or distinctive problems in escaping from poverty. Here we seek to establish whether, in comparison with cross-sectional measures, persistent poverty measures also provide a better measure of exclusion from a minimally acceptable way of life and relate with other important variables in a logical fashion. Our analysis draws upon the first three waves of the ECHP and shows that a persistent poverty measure does constitute a significant improvement over its cross-sectional counterpart in the explanation of levels of deprivation. Persistent poverty is related to life-style deprivation in a manner that comes close to being uniform across countries. The measure of persistence also conforms to our expectations of how a poverty measure should behave in that, unlike relative income poverty lines, defining the threshold level more stringently enables us to identify progressively groups of increasingly deprived respondents. Overall the persistent poverty measure constitutes a significant advance on cross-sectional income measures. However, there is clearly a great deal relating to the process of accumulation and of erosion of resources, which is not fully captured in the persistent poverty measure. In the absence of such information, there is a great deal to be said for making use of both types of indictors in formulating and evaluating policies while we continue to improve our understanding of longer-term processes.

Income, deprivation, and economic strain. An analysis of the European community household panel

This paper is concerned with the relationship between household income and life-style deprivation, and their combined impact on households' perceptions of economic strain. It takes as a point of departure findings from a number of European countries showing that the relationship between income and deprivation is weaker than widely assumed and that relative income poverty lines may perform poorly in terms of identifying the most deprived households. It proceeds to examine how far these conclusions about income and deprivation can be generalized to the countries included in the first wave of the European Community Household Panel. Results show that five distinct dimensions of deprivation emerge from an overall European analysis and that these are consistent across individual countries. While a good deal of similarity is observed in the income-deprivation relationship, countries differ in the strength of relationship between income and what is termed 'current liferstyle deprivation' with the relationship being generally weakest in the richer countries. The implications of these findings for the use of relative income poverty lines are developed. Extending this analysis to an assessment of how income and deprivation combine to influence perceptions of economic strain, we show that within-nation reference group processes operating in a uniform manner across countries can account for the bulk of the variation in strain. Cross-national differences can be accounted for by corresponding variation in income and deprivation levels.

The relationship between income and deprivation: A dynamic perspective

Income poverty lines may fail to distinguish households experiencing deprivation/exclusion. Analysing a large sample of Irish households, we find that current income is an important influence on deprivation levels, hut so are many other aspects of a household's current situation and how it arrived there. It is also important to distinguish different dimensions in using deprivation indicators with income to measure poverty.

Analyzing Intergenerational Influences on Income Poverty & Economic Vulnerability with EU-SILC

The European Union Statistics of Income and Living Conditions
(EU-SILC) 2005 wave includes a special module on inter-generational
transmission of poverty. In addition to the standard data relating to income
and material deprivation, information relating to parental background and
childhood circumstances was collected for all household members aged over
24 and less than 66 at the end of the income reference period. In principle,
the module provides an unprecedented opportunity to apply a welfare regime
perspective to a comparative European analysis of the relationship between
poverty and social exclusion and parental characteristics and childhood
economic circumstances. In this paper, we seek to exploit such potential. In
pursuing this objective, it is necessary to take into account some of the
limitations of the data. We do by restricting our attention to a set of
countries where data issues seem less extreme. Finally, we compare findings
from one dimensional and multidimensional approaches to poverty and social
exclusion in order to provide an assessment of the extent to which our
analysis of welfare regime variation provides a coherent account of the
intergenerational transmission of disadvantage.