256 research outputs found
Permutation-invariant distance between atomic configurations
We present a permutation-invariant distance between atomic configurations,
defined through a functional representation of atomic positions. This distance
enables to directly compare different atomic environments with an arbitrary
number of particles, without going through a space of reduced dimensionality
(i.e. fingerprints) as an intermediate step. Moreover, this distance is
naturally invariant through permutations of atoms, avoiding the time consuming
associated minimization required by other common criteria (like the Root Mean
Square Distance). Finally, the invariance through global rotations is accounted
for by a minimization procedure in the space of rotations solved by Monte Carlo
simulated annealing. A formal framework is also introduced, showing that the
distance we propose verifies the property of a metric on the space of atomic
configurations. Two examples of applications are proposed. The first one
consists in evaluating faithfulness of some fingerprints (or descriptors), i.e.
their capacity to represent the structural information of a configuration. The
second application concerns structural analysis, where our distance proves to
be efficient in discriminating different local structures and even classifying
their degree of similarity
Ion transport through deformable porous media: derivation of the macroscopic equations using upscaling
We study the upscaling or homogenization of the transport of a multicomponentelectrolyte in a dilute Newtonian solvent through a deformable porous medium.The pore scale interaction between the flow and the structure deformation is taken into account.After a careful adimensionalization process, we first consider so-called equilibrium solutions,in the absence of external forces, for which the velocity and diffusive fluxes vanish andthe electrostatic potential is the solution of a Poisson-Boltzmann equation.When the motion is governed by a small static electric field and small hydrodynamic and elastic forces,we use O'Brien's argument to deduce a linearized model. Then we perform the homogenizationof these linearized equations for a suitable choice of time scale. It turns out thatthe deformation of the porous medium is weakly coupled to the electrokinetics systemin the sense that it does not influence electrokinetics although the latter one yieldsan osmotic pressure term in the mechanical equations. As a byproduct we find that theeffective tensor satisfies Onsager properties, namely is symmetric positive definite
Ăvaluation du risque d'implantation de progiciel
The implementation of large software packages is becoming increasingly common in organizations nowadays. While they can generate important benefits, these projects also entail risk. Many of these projects have caused large financial losses and have failed to realize the promised benefits. This paper presents a formal analysis of the risk associated with the implementation of large software packages. L'implantation de progiciels est de plus en plus courante dans les organisations. Si les bénéfices potentiels associés à ces solutions sont importants, les risques sont à l'avenant. Plusieurs projets ont été abandonnés ou ont entraßné des conséquences graves pour les organisations ayant amorcé ces initiatives. Cet article présente une analyse formelle du risque associé à l'implantation de progiciels intégrés.Information Systems, IS Project Risk Management, Software Packages, ERP, SystÚmes d'information, Gestion du risque de projets TI, Progiciels, Progiciels de gestion intégrée
Le risque : un modÚle conceptuel d'intégration
The following project report is the first of a sequence which will focus on integrated risk management. This report presents a conceptual model which goal is to define the concept of risk. This conceptual model integrates the definitions of multiple domains having an interest in risk management. With the model, a terminology is proposed. This conceptual model is a foundation upon which it will be possible to exchange methods and measures of risk between domains. Ce rapport de projet est le premier d'une série qui s'intéressera à la gestion intégrée du risque. Dans l'objectif de répondre à la question « qu'est-ce que le risque? », un modÚle conceptuel définissant le concept du risque est proposé. Ce modÚle conceptuel intÚgre les définitions du risque de différentes disciplines. Une terminologie a été élaborée pour accompagner le modÚle. Ce modÚle conceptuel tente d'élaborer une base à partir de laquelle pourra se faire l'échange de méthodes et de mesures entre les domaines s'intéressant au risque.Risk, integrated risk management, definition, integration, Risque, gestion intégrée du risque, définition, intégration
Merkel Cell Polyomavirus in Cutaneous Swabs
To assess the usefulness of using cutaneous swabs to detect Merkel cell polyomavirus (MCPyV) DNA, we analyzed swabs from persons with Merkel cell carcinoma (MCC), others with skin diseases, and healthy volunteers. MCPyV was detected in at least 1 sample from virtually all participants. Viral loads were higher in samples from patients with MCC
Histoire et anthropologie du monde ibérique
Wolfgang Kaiser, Bernard Vincent, Jean-FrĂ©dĂ©ric Schaub, directeurs dâĂ©tudesJordi Canal, Catarina Madeira Santos, Natalia Muchnik, Enric Porqueres i GenĂ©, Jean-Paul Zuñiga, maĂźtres de confĂ©rences Ă lâEHESSFrĂ©dĂ©rique Langue, chargĂ©e de recherche au CNRSGrĂ©goire Salinero, maĂźtre de confĂ©rences Ă lâUniversitĂ© Paris-I/PanthĂ©on-Sorbonne Histoire et anthropologie du monde ibĂ©rique Cette annĂ©e, particuliĂšrement intense avec vingt-six interventions encadrĂ©es par des discutants, nous nous sommes intĂ©re..
CRH-GEI â Groupe dâĂ©tudes ibĂ©riques
Wolfgang Kaiser, Jean-FrĂ©dĂ©ric Schaub, Bernard Vincent (*),Enric Porqueres i GenĂ©, directeurs dâĂ©tudesJordi Canal, Jean-Paul Zuñiga, Catarina Madeira Santos, Natalia Muchnik, maĂźtres de confĂ©rencesFrĂ©dĂ©rique Langue, directrice de recherche au CNRSGrĂ©goire Salinero, maĂźtre de confĂ©rences Ă lâUniversitĂ© Paris 1-PanthĂ©on-Sorbonne Histoire et anthropologie du monde ibĂ©rique La formule inaugurĂ©e pour notre sĂ©minaire lâannĂ©e derniĂšre sâest mieux installĂ©e cette annĂ©e. Ă cĂŽtĂ© de la mission de lieu d..
CRH â Groupe dâĂ©tudes ibĂ©riques (GEI)
Wolfgang Kaiser, Enric Porqueres i GenĂ©, Bernard Vincent, Jean-FrĂ©dĂ©ric Schaub, directeurs dâĂ©tudesJordi Canal, Natalia Muchnik, Catarina Madeira Santos, Jean-Paul Zuhiga, maĂźtres de confĂ©rencesFrĂ©dĂ©rique Langue, directrice de recherche au CNRSGrĂ©goire Sallnero, maĂźtre de confĂ©rences Ă lâUniversitĂ© Paris-I/PanthĂ©on-Sorbonne Histoire et anthropologie du monde ibĂ©rique Sur un rythme bimensuel, notre sĂ©minaire collectif est organisĂ© selon une double dĂ©marche. Il cherche tout dâabord Ă se constit..
Histoire et anthropologie du monde ibérique
Bernard Vincent, Wolfgang Kaiser, Jean-FrĂ©dĂ©ric Schaub, directeurs dâĂ©tudesJordi Canal, Enric Porqueres i GenĂ©, Jean-Paul Zuñiga, Catarina Madeira Santos, Natalia Muchnik, maĂźtres de confĂ©rencesMarie-Lucie Copete, maĂźtre de confĂ©rences Ă lâUniversitĂ© de NancyFrĂ©dĂ©rique Langue, chargĂ©e de recherche au CNRSStĂ©phane Michonneau, maĂźtre de confĂ©rences Ă lâUniversitĂ© de PoitiersGrĂ©goire SalinĂ©ro, maĂźtre de confĂ©rences Ă lâUniversitĂ© Paris-I Histoire et anthropologie du monde ibĂ©rique Cette annĂ©e, l..
Histoire et anthropologie du monde ibérique
Bernard Vincent, Wolfgang Kaiser, Jean-FrĂ©dĂ©ric Schaub, directeurs dâĂ©tudesJordi Canal, Enric Porqueres i GenĂ©, Jean-Paul Zuñiga, Catarina Madeira Santos, Natalia Muchnik, maĂźtres de confĂ©rencesMarie-Lucie Copete, maĂźtre de confĂ©rences Ă lâUniversitĂ© de NancyFrĂ©dĂ©rique Langue, chargĂ©e de recherche au CNRSStĂ©phane Michonneau, maĂźtre de confĂ©rences Ă lâUniversitĂ© de PoitiersGrĂ©goire SalinĂ©ro, maĂźtre de confĂ©rences Ă lâUniversitĂ© Paris-I Histoire et anthropologie du monde ibĂ©rique Cette annĂ©e, l..
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