Dans le cadre d'un projet de réalisation d'un système à base de connaissances, d'aide à la simplification de modèles, utilisant des techniques d'intelligence artificielle (IA) associées à un langage de représentation centrée objet, les travaux présentés dans ce mémoire constituent une contribution à la définition de l'expertise au point de vue de la simplification de modèles et du développement des outils de synthèse nécessaires à l'élaboration de la base de connaissances. Ce mémoire comporte, dans la première partie, une synthèse bibliographique des différentes techniques de réduction des systèmes continus linéaires stationnaires modélisés par une matrice de transfert ou une équation d'état. Des critères de choix d'une méthode de simplification sont définis pour mieux guider l'utilisateur dans sa démarche. La deuxième partie, par une analyse numérique et graphique, traite plus particulièrement de l'identification des dynamiques, nécessaire à tout découplage ou réduction. Sans calcul des valeurs propres ni des vecteurs propres, cette identification est réalisée par des méthodes géométriques permettant ainsi un étiquetage des dynamiques du système étudié. L'introduction d'une nouvelle méthode, associée aux cercles de gershgorin, permet par un changement de base diagonal optimal, de mieux localiser les valeurs propres de la matrice d'état du système. La aussi, des critères de choix portant sur le bon ou le mauvais conditionnement d'une matrice sont établis. Lorsqu'ils sont vérifiés, ces critères nous renseignent sur l'utilisation directe des méthodes géométriques de mise en évidence des dynamiques. Dans la troisième partie, nous proposons trois méthodes qui, par une transformation linéaire, permettent la bloc-diagonalisation de la matrice d'état du système, quel que soit son conditionnement, tout en regroupant dans chaque bloc les dynamiques considérées. Cette technique est basée sur le calcul de la signature de matrice et ne nécessite pas non plus la connaissance du spectre de celle-ci.

For years, scientists have noticed disruptions in animal breeding cycles, accompanied by increases in birth defects, sexual abnormalities and reproductive failure. Humans are not immune either, with sperm counts dropping by as much as 50% in recent decades and with women seeing a rise in hormone-related cancers, endometriosis and other disorders. This book traces the cause of these aberrations and diseases to the pervasive presence in the environment of chemicals that mimic hormones and trick the reproductive system. The conclusions are as obvious as they are inescapable - unless we make vital changes in the way we manufacture and employ the artefacts of our good life , there will be no life at all.

This book presents recent research using cognitive science to apprehend risk situations and elaborate new organizations, new systems and new methodological tools in response. The book demonstrates the reasons, advantages and implications of the association of the concepts of cognition and risk. It is shown that this association has strong consequences on how to apprehend critical situations that emerge within various activity domains, and how to elaborate responses to these critical situations.. The following topics are covered by the book: · Influence of the culture in risk management, · Influence of the risk communication in risk management, · User-centred design to improve risk situation management, · Designing new tools to assist risk situation management, · Risk prevention in industrial activities.

This edited collection of articles addresses aspects of medical care in which human error is associated with unanticipated adverse outcomes. For the purposes of this book, human error encompasses mismanagement of medical care due to: * inadequacies or ambiguity in the design of a medical device or institutional setting for the delivery of medical care; * inappropriate responses to antagonistic environmental conditions such as crowding and excessive clutter in institutional settings, extremes in weather, or lack of power and water in a home or field setting; * cognitive errors of omission and commission precipitated by inadequate information and/or situational factors -- stress, fatigue, excessive cognitive workload. The first to address the subject of human error in medicine, this book considers the topic from a problem oriented, systems perspective; that is, human error is considered not as the source of the problem, but as a flag indicating that a problem exists. The focus is on the identification of the factors within the system in which an error occurs that contribute to the problem of human error. As those factors are identified, efforts to alleviate them can be instituted and reduce the likelihood of error in medical care. Human error occurs in all aspects of human activity and can have particularly grave consequences when it occurs in medicine. Nearly everyone at some point in life will be the recipient of medical care and has the possibility of experiencing the consequences of medical error. The consideration of human error in medicine is important because of the number of people that are affected, the problems incurred by such error, and the societal impact of such problems. The cost of those consequences to the individuals involved in medical error, both in the health care providers' concern and the patients' emotional and physical pain, the cost of care to alleviate the consequences of the error, and the cost to society in dollars and in lost personal contributions, mandates consideration of ways to reduce the likelihood of human error in medicine. The chapters were written by leaders in a variety of fields, including psychology, medicine, engineering, cognitive science, human factors, gerontology, and nursing. Their experience was gained through actual hands-on provision of medical care and/or research into factors contributing to error in such care. Because of the experience of the chapter authors, their systematic consideration of the issues in this book affords the reader an insightful, applied approach to human error in medicine -- an approach fortified by academic discipline.

Use of and trade in wildlife is a fact of life for human society around the globe. Article IV of the CITES Convention requires that exporting countries restrict trade in Appendix II species to levels that are not detrimental either to species? survival, or to their role within the ecosystems in which they occur (known as the ?non-detriment finding?). Based on two workshops convened by IUCN to develop some pragmatic assistance for Scientific Authorities, this publication presents the background to the development of the non-detriment finding checklist and explains how the checklist itself is designed to work, in the hope that Scientific Authority staff will take and develop the parts of the approach that they find useful.

For many years, as a direct result of international governmental concern, the nuclear power industry has been at the forefront of industrial safety. This text represents a cross-disciplinary look at the human factors developments in this industry, with wider applications for the entire industrial sector. Technical, psychological and social aspects