Probabilistic Graphical Models on Multi-Core CPUs using Java 8

In this paper, we discuss software design issues related to the development of parallel computational intelligence algorithms on multi-core CPUs, using the new Java 8 functional programming features. In particular, we focus on probabilistic graphical models (PGMs) and present the parallelisation of a collection of algorithms that deal with inference and learning of PGMs from data. Namely, maximum likelihood estimation, importance sampling, and greedy search for solving combinatorial optimisation problems. Through these concrete examples, we tackle the problem of defining efficient data structures for PGMs and parallel processing of same-size batches of data sets using Java 8 features. We also provide straightforward techniques to code parallel algorithms that seamlessly exploit multi-core processors. The experimental analysis, carried out using our open source AMIDST (Analysis of MassIve Data STreams) Java toolbox, shows the merits of the proposed solutions.Comment: Pre-print version of the paper presented in the special issue on Computational Intelligence Software at IEEE Computational Intelligence Magazine journa

Bot IT2: a new scorpion toxin to study receptor site on insect sodium channels

AbstractThe insect-specific Bothus occitanus tunetanus IT2 toxin is distinguishable from other scorpion toxins by its amino acid sequence and effects on sodium conductance. The present study reveals that Bot IT2 possesses in cockroach neuronal membranes a single class of high affinity (Kd=0.3±0.1 nM) and low capacity (Bmax=2.4±0.5 pmol/mg) binding sites. Competitive binding experiments with several known sodium channel neurotoxins reveal that the Bot IT2 binding site is in close proximity to the other toxins.© 1997 Federation of European Biochemical Societies

Statistiques des valeurs extrêmes dans le cas de lois discrètes

Nous proposons une méthode basée sur la notion de quantiles extrêmes pour générer un système d'alertes pour la détection de clusters temporels d'extrêmes dans une série chronologique. A cette fin, nous développons deux approches, l'une utilisant une approximation du temps de retour d'un événement extrême, quelle que soit la nature des données, et l'autre basée sur la théorie classique des valeurs extrêmes après lissage des données discrètes en données continues. Cette méthode permet ainsi de définir un système de surveillance et de prévision. Une illustration en est proposée dans le cadre de la prévision pour des applications en finance ainsi que pour la mise en place d'un système de surveillance en épidémiologie sur données réelles.applications en assurance et finance ; clusters ; détection d'événements extrêmes ; épidémiologie ; niveau de retour ; quantiles extrêmes ; temps de retour ; Théorie des Valeurs Extrêmes ; surveillance

Predicting EQ-5D from the Parkinson's disease questionnaire PDQ-8 using multi-dimensional Bayesian network classifiers

The impact of the Parkinson's disease and its treatment on the patients' health-related quality of life can be estimated either by means of generic measures such as the european quality of Life-5 Dimensions (EQ-5D) or specific measures such as the 8-item Parkinson's disease questionnaire (PDQ-8). In clinical studies, PDQ-8 could be used in detriment of EQ-5D due to the lack of resources, time or clinical interest in generic measures. Nevertheless, PDQ-8 cannot be applied in cost-effectiveness analyses which require generic measures and quantitative utility scores, such as EQ-5D. To deal with this problem, a commonly used solution is the prediction of EQ-5D from PDQ-8. In this paper, we propose a new probabilistic method to predict EQ-5D from PDQ-8 using multi-dimensional Bayesian network classifiers. Our approach is evaluated using five-fold cross-validation experiments carried out on a Parkinson's data set containing 488 patients, and is compared with two additional Bayesian network-based approaches, two commonly used mapping methods namely, ordinary least squares and censored least absolute deviations, and a deterministic model. Experimental results are promising in terms of predictive performance as well as the identification of dependence relationships among EQ-5D and PDQ-8 items that the mapping approaches are unable to detec

Mining multi-dimensional concept-drifting data streams using Bayesian network classifiers

In recent years, a plethora of approaches have been proposed to deal with the increasingly challenging task of mining concept-drifting data streams. However, most of these approaches can only be applied to uni-dimensional classification problems where each input instance has to be assigned to a single output class variable. The problem of mining multi-dimensional data streams, which includes multiple output class variables, is largely unexplored and only few streaming multi-dimensional approaches have been recently introduced. In this paper, we propose a novel adaptive method, named Locally Adaptive-MB-MBC (LA-MB-MBC), for mining streaming multi-dimensional data. To this end, we make use of multi-dimensional Bayesian network classifiers (MBCs) as models. Basically, LA-MB-MBC monitors the concept drift over time using the average log-likelihood score and the Page-Hinkley test. Then, if a concept drift is detected, LA-MB-MBC adapts the current MBC network locally around each changed node. An experimental study carried out using synthetic multi-dimensional data streams shows the merits of the proposed method in terms of concept drift detection as well as classification performance

Identifying entrepreneurial opportunities by nascent entrepreneurs in Sfax Region

The purpose of this paper is to identify variables influencing the identification of entrepreneurial opportunity by nascent entrepreneurs in Sfax region. These variables included the personality of entrepreneur, social network and prior knowledge. Theoretically, we have a conceptual framework privileged in recent entrepreneurship research (Shane & Venkataraman, 2000). Empirically, our research is based on an exploratory study, while adopting a deductive approach type. We used the questionnaire as a tool for data collection. The survey sample consisted of 80 nascent entrepreneurs in Sfax region. Our results showed that two variables among three that significantly predict the identification of entrepreneurial opportunity. These variables are social network and prior knowledge