Analysis of organizational conditions for risk management: the case study of a petrochemical site

This paper presents an ergonomic intervention in the petrochemical sector. The scheduled shutdown of one of the gas production sites has led the management to reduce the number of personnel on site, and then to get new recruits and experienced technicians from other sites as the policy for leaving personnel had not been properly planned, resulting in understaffing on site. Workers with seniority on the site, and who are also the most experienced do not accept the way newcomers are induced on site, whereas the management accuses them of resisting change. The intervention consisted in reconnecting local and corporate management through making the work activity visible and linking two sets of data that they held separately. Different types of analyses were made, work demography, decision making processes and tools used by the management, analysis of the building of career and work logics. Those different levels of analysis are gathered in macro-ergonomics, while showing the possible combinations between top down and bottom up approaches. The intervention resulted in concrete changes: HR simulation tool, training organisation, feedback.     

Preserving dominance relations through disaggregation: the evil and the saint

This article investigates the circumstances in which stochastic dominance relations at any finite degree at the household level can be assumed to be preserved at the individual level. We find necessary and sufficient conditions on the common sharing function adopted by households to divide the cake among a “strong” and a “weak” individual. The sharing function which maps the household income into the outcome of the weak individual must belong to the class of utility functions which supports the stochastic order. In addition, the household must follow a compensating rule, meaning that the share of resources devoted to the weak individual increases with household income. Applications to fiscal federalism are also proposed. “All inequality is a source of evil - for by the inferior more is lost in the account of happiness than is gained by the superior” J. Bentham, First Principle preparatory to Constitutional Code, 1822.      

Distribution asymptotique des autocorrélations ďun processus saisonnier non stationnaire

We examine the behaviour of the sample autocorrelations of a seasonal time series for which the first difference of order s (s ≥ 1) is stationary. The asymptotic distribution of the autocorrelations r'(k) based on uncentered data and of the autocorrelations r(k) based on centered data are derived. In each case, the asymptotic distribution is characterized as a function of the lag k and the parameters of the process. A simulation study was conducted in order to investigate the rate of convergence of the finite sample distributions of r(k) and r'(k) to their asymptotic counterparts and to evaluate the effect of centering or not centering the data on the distribution of autocorrelations.     

Model-based hierarchical clustering with Bregman divergences and Fishers mixture model: application to depth image analysis

Model-based clustering is a method that clusters data with an assumption of a statistical model structure. In this paper, we propose a novel model-based hierarchical clustering method for a finite statistical mixture model based on the Fisher distribution. The main foci of the proposed method are: (a) provide efficient solution to estimate the parameters of a Fisher mixture model (FMM); (b) generate a hierarchy of FMMs and (c) select the optimal model. To this aim, we develop a Bregman soft clustering method for FMM. Our model estimation strategy exploits Bregman divergence and hierarchical agglomerative clustering. Whereas, our model selection strategy comprises a parsimony-based approach and an evaluation graph-based approach. We empirically validate our proposed method by applying it on simulated data. Next, we apply the method on real data to perform depth image analysis. We demonstrate that the proposed clustering method can be used as a potential tool for unsupervised depth image analysis.     

Group decision making under uncertainty a note on the aggregation of “ordinal probabilities”

This paper is a first attempt to study the problem of aggregation of individual ordinal probabilistic beliefs in an Arrowian framework. We exhibit some properties an aggregation rule must fulfil; in particular we prove the existence of a quasi-dictator.     

Disabled people,inclusion and policy: better outcomes through a public health approach?

The social model of disability has implications for evaluation of disability policy. Public health analyses suggest that a population and environmental approach to enablement is more likely to impact positively on disabled people than person-centred action. The capacity of people living with disabilities to participate in a range of social activities and the attitudes of others to such participation are, along with environments, important factors contributing to disability situations and therefore the restriction of our promotion of personhood. These are areas where metrics could be used to evaluate the impact of disability policy.     

Job strain and psychotropic drug use among white-collar workers

The main objective of this study was to measure the association between simultaneous exposure to high psychological demand and low decision latitude at work and the use of psychotropic drugs among white-collar workers. A second objective was to determine whether social support at work modified this association. A cross-sectional study was performed that included 2786 workers from the public sector in the Greater Quebec City area. A self-administered questionnaire was used in order to evaluate psychological demand, decision latitude and social support at work. Psychotropic drug use was measured over a period of 2 days. The prevalence of psychotropic drug use among the participants was found to be 3.9%, even though 20.5% were exposed to job strain. The association between job strain and psychotropic drug use, after adjustment for social support at work, age, gender, education, family income, employment status, occupation, stressful life events, cigarette smoking, alcohol consumption and physical activity, was statistically significant (odds ratio: 4.5, 95% CI 1.7?12.2). Social support did not appear to modify this association. The results of this study suggest that job strain might be a determinant of psychotropic drug use among white collar workers. Social support at work does not appear, however, to modify this association.     

Conditioning Capacities and Choquet Integrals: The Role of Comonotony

Choquet integrals and capacities play a crucial role in modern decision theory. Comonotony is a central concept for these theories because the main property of a Choquet integral is its additivity for comonotone functions. We consider a Choquet integral representation of preferences showing uncertainty aversion (pessimism) and propose axioms on time consistency which yield a candidate for conditional Choquet integrals. An other axiom characterizes the role of comonotony in the use of information. We obtain two conditioning rules for capacities which amount to the well-known Bayes' and Dempster–Schafer's updating rules. We are allowed to interpret both of them as a lack of confidence in information in a dynamic extension of pessimism. This revised version was published online in June 2006 with corrections to the Cover Date.