Parametric Modelling of Multivariate Count Data Using Probabilistic Graphical Models

Multivariate count data are defined as the number of items of different categories issued from sampling within a population, which individuals are grouped into categories. The analysis of multivariate count data is a recurrent and crucial issue in numerous modelling problems, particularly in the fields of biology and ecology (where the data can represent, for example, children counts associated with multitype branching processes), sociology and econometrics. We focus on I) Identifying categories that appear simultaneously, or on the contrary that are mutually exclusive. This is achieved by identifying conditional independence relationships between the variables; II)Building parsimonious parametric models consistent with these relationships; III) Characterising and testing the effects of covariates on the joint distribution of the counts. To achieve these goals, we propose an approach based on graphical probabilistic models, and more specifically partially directed acyclic graphs

Correlation crises in insurance and finance, and the need for dynamic risk maps in ORSA

We explain why correlation crises may occur in insurance and finance. These phenomena are not taken into account in Solvency II standard formula. We show the importance of taking them into account in internal models or partial internal models. Given the variety of scenarios that could lead to correlation crises and their different potential impacts, we support the idea that ORSA (Own Risk and Solvency Assessment) reports of insurance companies should include dynamic and causal correlation crises analyzes.

La formation d’enseignants entre utilitarisme et cycles de Don : illustration en éducation physique

La formation des enseignants est généralement conçue en termes de transmission/construction utilitaire de connaissances et de compétences, et les formateurs valorisent le plus souvent l’adhésion, au moins formelle, à une logique utilitariste. Cependant, certains faits significatifs ne sont pas explicables dans cette logique. Ces faits sont analysés à partir de la théorie du Don dans des cas d’aide spontanée et des dispositifs de conseil chez des étudiants, des enseignants stagiaires et des formateurs. L’analyse montre que la nature des liens de confiance ou de défiance qui se tissent entre formateurs et formés pourrait avoir une influence dans la formation des enseignants. Ces liens permettent la réalisation de cycles de don ou de vengeance qui autorisent ou non le transfert de connaissances chez les enseignants nouveaux venus.In general, teacher training is envisaged in terms of transmission/construction of knowledge and competencies, and trainers most often place value on a utilitarian logic, as least in a formal sense. However, certain significant events are not explained using this logic. These situations are analyzed based on the theory of the “Gift” in cases of spontaneous help and advice between students, teacher mentors, and teacher trainers. The analysis shows that nature of relationships, being either those of confidence or defiance, that develop between trainers and their students can impact on teacher training. These links show the presence of cycles of gift and of vengeance that facilitate or prevent the transfer of knowledge to newly arrived teachers.La formación docente se concibe en general en términos de transmisión/construcción utilitaria de conocimientos y de competencias, y los formadores habitualmente valoran la adhesión, por lo menos formal, a una lógica utilitarista. Sin embargo, algunos hechos significativos no se pueden explicar dentro de esta lógica. Estos hechos son analizados a partir de la teoría del Don en unos casos de ayuda espontánea y de dispositivos de apoyo con estudiantes, docentes en prácticas y formadores. El análisis muestra que la naturaleza de los lazos de confianza o de desconfianza que se generan entre formadores y formados podría influir en la formación docente. Estos lazos permiten la realización de ciclos de don o de venganza que autorizan o no la transferencia de conocimientos en los docentes recién llegados

Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients.

IntroductionRespiratory variation in arterial pulse pressure is a reliable predictor of fluid responsiveness in mechanically ventilated patients with circulatory failure. The main limitation of this method is that it requires an invasive arterial catheter. Both arterial and pulse oximetry plethysmographic waveforms depend on stroke volume. We conducted a prospective study to evaluate the relationship between respiratory variation in arterial pulse pressure and respiratory variation in pulse oximetry plethysmographic (POP) waveform amplitude.MethodThis prospective clinical investigation was conducted in 22 mechanically ventilated patients. Respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude were recorded simultaneously in a beat-to-beat evaluation, and were compared using a Spearman correlation test and a Bland-Altman analysis.ResultsThere was a strong correlation (r2 = 0.83; P < 0.001) and a good agreement (bias = 0.8 +/- 3.5%) between respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude. A respiratory variation in POP waveform amplitude value above 15% allowed discrimination between patients with respiratory variation in arterial pulse pressure above 13% and those with variation of 13% or less (positive predictive value 100%).ConclusionRespiratory variation in arterial pulse pressure above 13% can be accurately predicted by a respiratory variation in POP waveform amplitude above 15%. This index has potential applications in patients who are not instrumented with an intra-arterial catheter

Approche graphique pour la modélisation statistique de la dépendance entre activités journalières

http://mistis.inrialpes.fr/workshop-statistique-transport.html Transparents disponibles sur http://mistis.inrialpes.fr/docs/workshop-statistique-transport/slidesDurand.pdfInternational audienceIn this presentation, we introduce a new family of statistical models for the analysis of multivariate count data. We propose an application in modelling daily activity programs at the scale of individuals or families

The European community’s response to the central European challenge the Genesis of a European common foreign policy

This MA thesis deals with the European Community's response to the Central European challenge. The lack of explanatory and normative theories to explain the European integration process as a whole demonstrates that it has been driven by Member States' interests and could be heavily influenced by external aspects. Despite the different political models of organisation (i.e. federation, confederation or international organisation) at the disposition of several states to organise themselves to tackle international problems, West European member states did not completely subscribe to any of these and that makes the European Union the political invention of this century. The politico-administrative model of the European Union is the result of a original and unprecedented bargaining to preserve national interests and supranational efficiency both at the same time. This process is both the source of its originality and the reason of its relative inefficiency when compared to the United States of Germany. However the European Union survives and proves the relevance in the international scene when confronted to external effects. Our argument is that Central Europe could be considered as one of the external factors that might push the European Union to strengthen its decision making process and to render its action more efficient and responsive to Central European needs. This thesis deliberately limits itself to the economic and political sides of European external policy and shows the evolution of the methods, structures and concepts that the European Union used to build up a Common Commercial Policy and to set up the Common Foreign and Security Policy

Spherical angular spectrum and the fractional order Fourier transform

International audienceThe notion of a spherical angular spectrum leads to the decomposition of the field amplitude on a spherical emitter into a sum of spherical waves that converge onto the Fourier sphere of the emitter. Unlike the usual angular spectrum, the spherical angular spectrum is propagated as the field amplitude, in a way that can be expressed by a fractional order Fourier transform

Integration of Heterogeneous Cultural Heritage Data in a Web-based <br />Information System: A Case Study from Vianden Castle, Luxembourg

ISBN 978-963-8046-90-1International audienceThe project presented here proposes the first implementation of a Web-based Information System for the conservation, handling, and use of site data. The case study is the castle of Vianden in Luxembourg, on which considerable archaeological data have accumulated over the years. There is a recognized need in archaeology for a tool that will allow for fast, effective, and flexible exploratory analysis of data, especially at spatial and temporal levels. We have developed such an Information System with maximal portability by using Extensible Markup Language (XML) and Extensible Stylesheet Language (XSL) for data exchange. Our system consists of several interfaces permitting different types of access to heterogeneous information. We propose a description of the data in textual interfaces along with images, and dynamic links to this data through interactive 2D and 3D representations. The 2D images, photos, or vectors are generated in Scalable Vector Graphics (SVG), while 3D models are generated in X3

A web information system for the management and the dissemination of Cultural Heritage data.

Safeguarding and exploiting Cultural Heritage induce the production of numerous and heterogeneous data. The management of these data is an essential task for the use and the diffusion of the information gathered on the field. Previously, the data handling was a hand-made task done thanks to efficient and experienced methods. Until the growth of computer science, other methods have been carried out for the digital preservation and treatment of Cultural Heritage information. The development of computerized data management systems to store and make use of archaeological datasets is then a significant task nowadays. Especially for sites that have been excavated and worked without computerized means, it is now necessary to put all the data produced onto computer. This allows preservation of the information digitally (in addition with the paper documents) and offers new exploitation possibilities, like the immediate connection of different kinds of data for analyses, or the digital documentation of the site for its improvement. Geographical Information Systems have proved their potentialities in this scope, but they are not always adapted to the management of features at the scale of a particular archaeological site. Therefore this paper aims to present the development of a Virtual Research Environment dedicated to the exploitation of intra-site Cultural Heritage data. The Information System produced is based on open-source software modules dedicated to the Internet, so users can avoid being software driven and can register and consult data from different computers. The system gives the opportunity to do exploratory analyses of the data, especially at spatial and temporal levels. The system is compliant to every kind of Cultural Heritage site and allows management of diverse types of data. Some experimentation has been done on sites managed by the Service of the National Sites and Monuments of Luxembourg