15771 research outputs found
Sort by
Multitask Principal Component Analysis
No full textPrincipal Component Analysis (PCA) is a canonical and well-studied tool for dimension- ality reduction. However, when few data are available, the poor quality of the covariance estimator at its core may compromise its performance. We leverage this issue by casting the PCA into a multitask framework, and doing so, we show how to solve simultaneously several related PCA problems. Hence, we propose a novel formulation of the PCA prob- lem relying on a novel regularization. This regularization is based on a distance between subspaces, and the whole problem is solved as an optimization problem over a Riemannian manifold. We experimentally demonstrate the usefulness of our approach as pre-processing for EEG signals.nonouirechercheInternationa
Intergenerational learning in the firm's strategic dynamic : a comparison between France and Japan
No full textNotre thèse s’intéresse au rapport entre l’apprentissage intergénérationnel et la dynamique stratégique de l’entreprise, dans une démarche comparative franco-japonaise. La littérature sur les générations, sur l’apprentissage et les capacités dynamiques constitue notre cadre théorique. Dans une étude qualitative multi-cas réalisée en France et au Japon, quatorze cas d’apprentissage intergénérationnel sont analysés. Nos résultats indiquent que le rapport entre l’apprentissage intergénérationnel et la dynamique stratégique de l’entreprise varient entre les cas de continuité et les cas de changement, tandis que le contexte culturel influence la formation des générations et les pratiques d’apprentissage intergénérationnel. Nous montrons ainsi le rôle de l’organisation dans la formation des générations, les enjeux stratégiques de l’apprentissage intergénérationnel et l’encastrement culturel des pratiques managériales.This thesis is a comparative study of the relationships between intergenerational learning and the firm’s strategic dynamic, lead in France and Japan. The conceptual framework builds on the literature regarding generation, learning and dynamic capabilities. A qualitative multi-case study was conducted in France and Japan and fourteen cases of intergenerational learning were analyzed. The empirical results show that the relationships between intergenerational learning and the dynamic of the firm’s strategy vary between the state of stability and change. The cultural contexts influence the creation of the generations and intergenerational learning practices. These results highlight the role of organizations in the creation of generations, the strategic issue of intergenerational learning and give insights about the cultural embeddedness of managerial practices
Customer orientation and firm’s business performance : A moderated mediation model of environmental customer innovation and contextual factors
No full textThe purpose of this study is to develop a better theoretical and empirical understanding of the causal and contextual mechanisms explaining the relationship between customer orientation and business performance.nonouirechercheInternationa
Can evoking nature in advertising mislead consumers? The power of ‘executional greenwashing'
No full textThis paper examines the ‘executional greenwashing’ effect, defined as the use of nature-evoking elements in advertisements to artificially enhance a brand's ecological image. Using classic models of information processing and persuasion, the research tests whether ‘executional greenwashing’ differs as a function of consumer knowledge about environmental issues in the product category and whether environmental performance information can counterbalance the effect by helping consumers form an accurate evaluation of the brand's ecological image. Three experiments with French consumers reveal that evoking nature does mislead consumers in their evaluation of a brand's ecological image, especially if they have low knowledge of environmental issues. Two indicators of environmental performance, based on current international policies, are tested to counteract ‘executional greenwashing’. Whereas a raw figure is not sufficient to help non-expert consumers revise their judgment, accompanying the figure with a traffic-light label eliminates ‘executional greenwashing’ amongst both experts and non-experts. Theoretical and regulatory implications are discussed.nonouirechercheInternationa
Hausdorff distances between distributions using optimal transport and mathematical morphology
No full textLecture Notes in Computer Science, Vol. 9082In this paper we address the question of defining and computing Hausdorff distances between distributions in a general sense. We exhibit some links between Prokhorov-Lévy distances and dilation-based distances. In particular, mathematical morphology provides an elegant way to deal with periodic distributions. The case of possibility distributions is addressed using fuzzy mathematical morphology. As an illustration, the proposed approaches are applied to the comparison of spatial relations between objects in an image or a video sequence, when these relations are represented as distributions.nonouirechercheInternationa
Pivots et Elections
No full textVoir lien (Hal archives ouvertes) vers la pré-publicationCe chapitre décrit de manière sommaire les principaux modèles de vote stratégique avec un grand nombre d'électeurs, dits modèles d'élections de masse. Dans ces modèles, on suppose que l'électeur décide de son vote en fonction des pivots, c'est-à-dire des événements où son unique voix va faire une différence quant au résultat de l'élection. Les principaux messages de ces modèles sont illustrés avec des exemples simples ; ils sont ensuite présentés plus en détail ; on examine enfin leurs applications et limites, notamment en ce qui concerne l'économie expérimentale.nonnonrechercheInternationa
Analyse des dynamiques d’investissement de long terme dans les marches électriques sous contraintes de développement des renouvelables intermittentes et d’adéquation de capacité
No full textLes marchés électriques libéralisés sont supposés assurer la coordination de long terme des investissements afin de garantir sécurité d’approvisionnement, viabilité et compétitivité. Dans le modèle de référence energy-only, la formation des prix par alignement sur le coût variable de l’équipement marginal sur les marchés horaires successifs fournit un signal prix pour les investisseurs. Cependant, en pratique, ce modèle est remis en question quant à sa capacité à déclencher des investissements dans les technologies bas-carbone et en particulier les énergies renouvelables (EnR) et quant à sa capacité à garantir la sécurité d’approvisionnement. Cette thèse cherche d’abord à caractériser ces deux défaillances de marché puis s’intéresse à différentes solutions pour faire face à chacune d’entre elles. Pour cela, la réflexion s’appuie sur un modèle en System Dynamics développé afin de simuler les investissements dans les marchés électriques.D’une part, les résultats montrent que le remplacement des mécanismes de support hors marché par des investissements par le marché avec l’aide d’un prix du carbone apparait comme une solution pour déclencher le développement des EnR à condition d'un engagement politique fort en faveur d’un prix du carbone élevé. D’autre part, il apparait aussi que le marché energy-only avec des prix plafonnés ne parvient pas à assurer l’adéquation de capacité. L’ajout d’un marché de capacité ou la suppression du plafond de prix permettent une amélioration en termes de nombre d’heure de délestage et de bien-être collectif. De plus, le marché de capacité apparaît comme le meilleur choix pour le régulateur parmi les architectures de marché considérées.In liberalised electricity systems, power markets are expected to ensure the long-term coordination of investments in order to guarantee security of supply, sustainability and competitiveness. In the reference energy-only market, it relies on the ability of power markets — where the hourly price is aligned with the marginal cost of the system — to provide an adequate price-signal for investors. However, in practice, questions have been raised about its ability to trigger investments in low-carbon technologies including in particular Renewable Energy Sources of Electricity (RES-E), and its ability to ensure capacity adequacy. After a characterisation of these market failures, this dissertation tackles the two research topics within a methodological framework based on a System Dynamics model developed to simulate private investment decisions in power markets.First, the results show that substituting out-of-market support mechanisms for RES-E by market-based investments helped by the sole implementation of a carbon price appears as a feasible solution to trigger RES-E development providing that there is a political commitment on a high carbon price. Second, it also appears that the energy-only market with price cap is ineffective to ensure capacity adequacy. Adding a capacity market or removing the price cap both bring benefits in terms of loss of load expectation and social welfare. Moreover, the capacity market is identified as the best option for regulators among the considered market designs
Urban intersections effect on pedestrian accessibility
No full textDo intersections affect the convenience, pleasantness and quality of walk across the city? The study investigates the effect of spatial and operational configuration of street junctions on walking. A method for analyzing and evaluating urban intersections from the point of view of pedestrians and its operative application in the town of Alghero (Italy) is presented. An ELECTRE TRI rating/classification procedure was used to classify intersectionsaccording to their level of impedance for walking. Since the proposed method is reasonable simple to implement and its results have proven to be easilycommunicable, we believe it can be a useful planning support tool for the development of transportation policies aimed at enhancing pedestrian mobility and a practicable support aid for decision makers interested in prioritize interventions in cities. Furthermore, the proposed evaluation procedure may be incorporated into other evaluation models of urbanwalkability, which frequently put minor attention on (when not entirely ignoring) the effects of intersections on the overall walkability of places.nonouirechercheInternationa
Collective Intelligence Support Protocol: a systemic approach for collaborative architectural design
No full textLecture Notes in Computer Science, n°9320The collaborative architectural design process can be difficult to generate and maintain, especially when consisting of large teams, time constraints and long distance as it requires a higher sense of working together. However, a formal description of collaborative design as a system made of elements, agents, sub-systems and relationships could open a path to potentially improve production efficiency and stream collective intelligence. The CISP is a first attempt methodology to support collaborative design based on the empirical analysis of a single case study involving a multi-disciplinary team competing in an international architectural idea competition. The methodology operates through interdependencies on three layers: organization, planning and shared workspace. By articulating methods, tools, team members and project phases, the CISP fosters an integrated design system and a fluent design process.nonouirechercheInternationa
Havannah and TwixT are PSPACE-complete
No full textNumerous popular abstract strategy games ranging from Hex and Havannah via TwixT and Slither to Lines of Action belong to the class of connection games. Still, very few complexity results on such games have been obtained since Hex was proved pspace-complete in the early 1980s.We study the complexity of two connection games among the most widely played ones, i.e., we prove that Havannah and TwixT are pspace-complete. The proof for Havannah involves a reduction from Generalized Geography and is based solely on ring-threats to represent the input graph. The reduction for TwixT builds up on previous work as it is a straightforward encoding of Hex.nonouirechercheInternationa