571 research outputs found

    Robustness for a Liouville type theorem in exterior domains

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    We are interested in the robustness of a Liouville type theorem for a reaction diffusion equation in exterior domains. Indeed H. Berestycki, F. Hamel and H. Matano (2009) proved such a result as soon as the domain satisfies some geometric properties. We investigate here whether their result holds for perturbations of the domain. We prove that as soon as our perturbation is close to the initial domain in the C2,αC^{2,\alpha} topology the result remains true while it does not if the perturbation is not smooth enough

    Front blocking and propagation in cylinders with varying cross section

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    In this paper we consider a bistable reaction-diffusion equation in unbounded domains and we investigate the existence of propagation phenomena, possibly partial, in some direction or, on the contrary, of blocking phenomena. We start by proving the well-posedness of the problem. Then we prove that when the domain has a decreasing cross section with respect to the direction of propagation there is complete propagation. Further, we prove that the wave can be blocked as it comes to an abrupt geometry change. Finally we discuss various general geometrical properties that ensure either partial or complete invasion by 1. In particular, we show that in a domain that is "star-shaped" with respect to an axis, there is complete invasion by 1

    Business and the Risk of Crime in China

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    The book analyses the results of a large scale victimisation survey that was conducted in 2005-06 with businesses in Hong Kong, Shanghai, Shenzhen and Xi’an. It also provides comprehensive background materials on crime and the criminal justice system in China. The survey, which measured common and non-conventional crime such as fraud, IP theft and corruption, is important because few crime victim surveys have been conducted with Chinese populations and it provides an understanding of some dimensions of crime in non-western societies. In addition, China is one of the fastest-growing economies in the world and it attracts a great amount of foreign investment; however, corruption and economic crimes are perceived by some investors as significant obstacles to good business practices. Key policy implications of the survey are discussed

    Bad smells in design and design patterns

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    International audienceTo give a consistent and more valuable property on models, model-driven processes should be able to reuse the expert knowledge generally expressed in terms of patterns. We focus our work on the design stage and on the systematically use of design patterns. Choose a good design pattern and ensure the correct integration of the chosen pattern are non trivial for a designer who wants to use them. To help designers, we propose design inspection in order to detect “bad smells in design” and models reworking through use of design patterns. The automatic detection and the explanation of the misconceptions are performed thanks to spoiled patterns. A “spoiled pattern” is a pattern which allows to instantiate inadequate solutions for a given problem: requirements are respected, but architecture is improvable

    Hong Kong International Violence Against Women Survey

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    Final Report of the 2006 Hong Kong IVAW

    Détection, Explications et Restructuration de défauts de conception : les patrons abßmés.

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    Models driven engineering considers models first class entities for the software development. The models driven processes must be able to take into account the know-how of experts, generally expressed in terms of analysis, architectural of design patterns. To choose the right pattern and to ensure its correct integration within a model constitute curbs with the systematic use of the good design practices. In order to reduce these tasks, we propose an approach based on the automatic inspection of models. In the same manner that there are code review activities aiming at checking the absence of bad coding practices in a program, we have tooled a design review activity identifying, explaining and correcting the bad design practices in a model. A spoiled pattern is comparable with a design pattern, its instantiations solving the same types of problems, but with a different and certainly improvable architecture. Experiments were carried out in order to collect spoiled patterns, allowing us to propose a catalog of bad practices, complementary to the GoF catalog. The detection of the instantiations of spoiled patterns in a UML model is related with a wide graph homomorphism. Graphs UML having typed vertexes, detection is based on local and global structural properties allowing the solving of this NP-Complete problem by successive filtering. Thus, this algorithm is able to detect all the possible instantiations of a spoiled pattern, by managing moreover prohibited and optional edges. The model fragment semantics is given by its intent which is validated by the designer. The intent of the detected fragments and the benefit of a replacement by the adequate pattern are deduced by requests on an ontology conceived for this purpose. The transformation of the fragments into instantiations of design pattern is carried out thanks to model refactoring automatically deduced from the structural differences between a spoiled pattern and an design pattern.L'ingĂ©nierie des modĂšles considĂšre les modĂšles comme des entitĂ©s de premiĂšre classe pour le dĂ©veloppement logiciel. Les processus dirigĂ©s par les modĂšles se doivent d'ĂȘtre capables de prendre en compte le savoir-faire d'experts, gĂ©nĂ©ralement exprimĂ© en termes de patrons, qu'ils soient d'analyse, de conception ou d'architecture. Choisir le bon patron et assurer sa bonne intĂ©gration au sein d'une modĂ©lisation constitue des freins Ă  l'utilisation systĂ©matique des bonnes pratiques de conception. Afin d'allĂ©ger ces tĂąches, nous proposons une approche basĂ©e sur l'inspection automatique des modĂšles. De la mĂȘme maniĂšre qu'il existe des revues de code visant Ă  vĂ©rifier l'absence de mauvaises pratiques de codage dans un programme, nous avons outillĂ© une activitĂ© de revue de conception identifiant, expliquant et corrigeant les mauvaises pratiques de conception dans un modĂšle. Un patron abĂźmĂ© est comparable Ă  un patron de conception, ses contextualisations rĂ©solvant les mĂȘmes types de problĂšmes, mais avec une architecture diffĂ©rente et certainement amĂ©liorable. Des expĂ©rimentations ont Ă©tĂ© menĂ©es afin de collecter des patrons abĂźmĂ©s, nous amenant Ă  proposer un catalogue de mauvaises pratiques, complĂ©mentaire au catalogue du GoF. La dĂ©tection des contextualisations de patrons abĂźmĂ©s dans un modĂšle UML est apparentĂ©e Ă  un morphisme de graphe Ă©tendu. Les graphes UML ayant des sommets typĂ©s, la dĂ©tection s'appuie sur des particularitĂ©s structurelles locales et globales permettant de rĂ©soudre ce problĂšme NP-Complet par des filtrages successifs. Cet algorithme est ainsi capable de dĂ©tecter toutes les contextualisations possibles d'un patron abĂźmĂ©, en gĂ©rant de plus les arcs interdits et facultatifs. La sĂ©mantique d'un fragment de modĂšle est donnĂ©e par son intention et celle-ci est validĂ©e par le concepteur. L'intention des fragments dĂ©tectĂ©s et les bĂ©nĂ©fices d'un remplacement par le patron adĂ©quat sont dĂ©duits par des requĂȘtes sur une ontologie conçue Ă  cet effet. La transformation des fragments en contextualisations de patrons de conception est rĂ©alisĂ©e grĂące Ă  des restructurations de modĂšles dĂ©duites automatiquement des diffĂ©rences structurelles entre un patron abĂźmĂ© et un patron de conception

    1 Sharing Bad Practices in Design to Improve the Use of Patterns

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    To ensure the use of good analysis and design practices and an easier maintenance of software, analysts and designers may use patterns. To help them, we propose models inspection in order to detect instantiations of “spoiled pattern ” and models reworking through the use of the design patterns. As a design pattern allows the instantiation of the best known solution for a given problem, a “spoiled pattern ” allows the instantiation of alternative solutions for the same problem: requirements are respected, but architecture is improvable. We have collected a set of alternative solutions and deduced the corresponding spoiled patterns. We have defined a first catalog of these improvable practices from several experiments with students. To overcome the limits imposed by this method (restricted public, limited problems and tiresome validation process), we would like to open this problematic to the expert community. Therefore, we propose a collaborative website sharing bad practices in object oriented design to improve the use of patterns
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