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Some relationships between fuzzy sets, mathematical morphology, rough sets, F-transforms, and formal concept analysis
No full textIn this paper we extend some previously established links between the derivation operators used in formal concept analysis and some mathematical morphology operators to fuzzy concept analysis. We also propose to use mathematical morphology to navigate in a fuzzy concept lattice and perform operations on it. Links with other lattice-based for malisms such as rough sets and F-transforms are also established. This paper proposes a discussion and new results on such links and their potential interest.nonouirechercheInternationa
Coût de la dette et facteurs de risque extra-financiers
No full textCette thèse a pour ambition d’analyser si la performance environnementale, sociale et de gouvernance (ESG) est intégrée par les marchés de la dette d'entreprise et souveraine. Le premier chapitre se concentre sur les informations ESG publiés à contenu négatif et leur impact négatif sur le coût de la dette. Plus exactement, dans les secteurs industriels et utilitaires les événements négatifs sociaux et de gouvernance font augmenter le coût de la dette. Également, un bon niveau général de performance ESG agit comme un mécanisme d'assurance contre ces événements négatifs. Dans un deuxième chapitre seront présentés les résultats d’une simulation de portefeuille intégrant la performance ESG d'entreprise. Un gérant de portefeuille peut améliorer le niveau agrégé de la performance ESG du portefeuille de 1,5 écart-type sans faire baisser la performance financière. Ainsi, le gérant peut combiner cette intégration avec des stratégies d'allocation d'actif financiers ou des stratégies de rendement absolu. Dans un troisième chapitre les résultats sur la réduction du coût de la dette dû à une bonne performance environnementale et sociale de souverains émergents seront analysés. Enfin dans le quatrième chapitre je décris comment la performance de gouvernance des souverains influence la différence entre le yield émis en devise étrangère et celui émis en devise locale. Dans les pays développés cette différence augmente avec le risque politique, i.e. le yield étranger augmente plus rapidement que le yield domestique. Dans les pays émergents, c'est l’effet inverse qui est observé. Cette différence entre les deux yields varie plus fortement avec un taux croissant de la dette domestique détenue par des investisseurs étrangers.This thesis analyzes if and to what extent debt markets value the environmental, social and governance (ESG) performance of firms and sovereigns. The first chapter shows that negative ESG news has a negative impact on the cost of debt of firms. The news relates to environmental and social events within the industrial/utilities sector. In this sector, a sound corporate social performance acts as an insurance against the adverse impact of negative environmental events on bond prices. The second chapter reveals that ESG scores integrated into portfolios do not change the financial performance ex post. A portfolio manager can increase the average ESG rating of her portfolio by 1.5 standard deviations without incurring cost. This leaves substantial room and opportunity for ESG ratings to be combined with asset allocation or absolute return strategies. The third chapter shows how ESG performance is linked to a lower cost of debt of emerging sovereigns. Research indicates that an emerging country’s average cost of capital decreases with its positive environmental and social performance. The fourth chapter discusses how governance performance may influence the spread of debt denominated in local and foreign currency. In developed countries, the spread between a foreign currency yield and a hedged local currency yield increases with our political risk indicator, i.e. the foreign yield increases faster than the domestic one. For emerging countries, the reverse trend is true. Interestingly, the foreign currency and local currency yield spreads move significantly stronger in absolute terms with increasing foreign investment participation in both emerging countries and developed countries’ debt markets
The Governmental Work in Cambodia from 1993 to 2015
No full textÀ travers l’analyse du travail gouvernemental de 1993 à 2015 dans l’optique de la stabilité constitutionnelle et politique, il s’est révélé que la transposition au Cambodge des grands principes de l’État de droit, de la démocratie libérale et pluraliste sur le modèle occidental, par la mise en œuvre des Accords de Paris de 1991 ne s'est pas effectuée de façon satisfaisante. L’objectif consistant à faire de la société cambodgienne, une société démocratique où chacun s’incline devant la loi, où la justice est indépendante du pouvoir exécutif, où les forces armées comme les forces économiques sont soumises à l'autorité publique gardienne de l’intérêt général, où à tout pouvoir se voit opposé un contre-pouvoir, n’a pas été atteint. Les obstacles à cette transposition effective résident dans le grand écart qui existe entre les principes du modèle importé, voire imposé, et les pesanteurs de l’histoire tragique que les Cambodgiens ont vécue entre les années 1970 et 1980, d’une part et les fondements traditionnels de la société cambodgienne encore très présents à ce jour d’autre part.Through the analysis of governmental work from 1993 to 2015 within the perspective of the constitutional and political stability, it is obvious clear that the implementation in Cambodia of the main principles of the Western model of the rule of law, liberal and pluralistic democracy, with the implementation of the 1991 Paris Agreements did not take place satisfactorily. The goal to make the Cambodian society, a democratic one where everyone obeys to the law, where justice is independent from the Executive where the armed forces as economic forces are subject to the public authority which is of the guardian general interest, where every power can be balanced by a counter-power, has not been reached. The obstacles to this actual transposition reside in the gap between the principles of an imported or imposed model and the burdens of the tragic history that Cambodians have lived between the years 1970 and 1980, on the one hand and the traditional foundations of Cambodian society still very present to nowadays on the other hand
Internal and International Vertical Specialization of Brazilian states– An Input-Output analysis
No full textL’OMC et l’OCDE notamment, suggèrent que le commerce en valeur ajoutée est une meilleure mesure des échanges que la valeur brute pour comprendre l’impact du commerce sur l’emploi, la croissance, la production etc. On utilise dans ce travail un tableau Input-Output pour l’année 2008 afin de calculer les valeurs ajoutées exportées par les États brésiliens. On distingue la valeur ajoutée exportée directement par un État de celle exportée indirectement via d’autres États. En utilisant la valeur ajoutée indirectement exportée, on définit l’ampleur de la spécialisation verticale entre les états brésiliens. On calcule également le contenu en importations des exportations des états. Même si la part du contenu en importations des exportations est peu élevée pour le Brésil, on montre l’importance du commerce inter-état pour certains états. La spécialisation verticale inter-état joue davantage en amont de la chaine de valeur, avant que le bien soit exporté à l’étranger. Néanmoins, la valeur ajoutée d’un état, exportée indirectement par un autre état, est équilibrée par la valeur ajoutée qu’il importe des autres états pour son exportation. Ainsi, les parts de chaque état dans l’exportation totale du Brésil en valeur brute ou en valeur ajoutée sont généralement proches.WTO, OECD with many others, suggest the trade in value-added would be a “better” measure than gross value to understand the impact of trade on employment, growth, production etc. We use in this work an Input-Output table for 2008, to calculate the value-added exported by Brazilian states. We distinguish the value-added exported directly by the state itself or indirectly via other states. Then, we define the extent of vertical specialization among Brazilian states by using value-added indirectly exported. We calculate equally the import content in states’ exports. If the share of import content in Brazilian exports is low, we show evidence that inter-state trade is quite high across some Brazilian states. Inter-state vertical specialization then operates at upstream stages of the value chain before the good be exported to foreign countries. However the value-added of a state; indirectly exported by another state is quite balanced by the value-added of its own exports which is imported from other states, then the export shares of each state in total Brazilian exports in value-added terms or in gross terms are close.nonouirechercheInternationa
Reoptimization under Vertex Insertion: Max Pk-Free Subgraph and Max Planar Subgraph
No full textThe reoptimization issue studied in this paper can be described as follows: given an instance I of some problem Π, an optimal solution OPT in I and an instance I' resulting from a local perturbation of I that consists of insertions or removals of a small number of data, we wish to use OPT to solve Π in I', either optimally or by guaranteeing an approximation ratio better than that guaranteed by an ex nihilo computation and with running time better than that needed for such a computation. We use this setting to study weighted versions of MAX Pk-FREE SUBGRAPH and MAX PLANAR SUBGRAPH, which are representatives of a broad class of problems known in the literature as maximum induced hereditary subgraph problems. We also show that the techniques presented allow us to handle BIN PACKING.nonouirechercheInternationa
The Complexity of Learning Separable ceteris paribus Preferences
No full textWe address the problem of learning preference relations on multi-attribute (or combinatorial) domains.We do so by making a very simple hypothesis aboutthe dependence structure between attributes thatthe preference relation enjoys, namely separability(no preferential dependencies between attributes).Given a set of examples consisting of comparisonsbetween alternatives, we want to output a separableCP-net, consisting of local preferences on each ofthe attributes, that fits the examples. We considerthree forms of compatibility between a CP-net anda set of examples, and for each of them we give useful characterizations as well as complexity results.ouinonouirechercheInternationa
Complexity and approximation of satisfactory partition problems
No full textThe Satisfactory Partition problem consists of deciding if a given graph has a partition of its vertex set into two nonempty parts such that each vertex has at least as many neighbors in its part as in the other part. This problem was introduced by Gerber and Kobler in 1998 and further studied by other authors but its complexity remained open until now. We prove in this paper that Satisfactory Partition, as well as a variant where the parts are required to be of the same cardinality, are NP-complete. We also study approximation results for the latter problem, showing that it has no polynomial-time approximation scheme, whereas a constant approximation can be obtained in polynomial time. Similar results hold for balanced partitions where each vertex is required to have at most as many neighbors in its part as in the other part.ouinonouirechercheInternationa
Approximating min-max (regret) versions of some polynomial problems
No full textWhile the complexity of min-max and min-max regret versions of most classical combinatorial optimization problems has been thoroughly investigated, there are very few studies about their approximation. For a bounded number of scenarios, we establish a general approximation scheme which can be used for min-max and min-max regret versions of some polynomial problems. Applying this scheme to shortest path and minimum spanning tree, we obtain fully polynomial-time approximation schemes with much better running times than the ones previously presented in the literature.ouinonouirechercheInternationa
Belief Change Based on Global Minimisation
No full textHyderabad, IndeA general framework for minimisation-based beliefchange is presented. A probleminstance ismade upof an undirected graph, where a formula is associ-ated with each vertex. For example, vertices mayrepresent spatial locations, points in time, or someother notion of locality. Information is shared between vertices via a process of minimisation overthe graph. We give equivalent semantic and syntactic characterisations of this minimisation. We alsoshow that this approach is general enough to capture existing minimisation-based approaches to belief merging, belief revision, and (temporal) extrapolation operators. While we focus on a set-theoreticnotion of minimisation, we also consider other approaches, such as cardinality-based and priority-based minimisation.ouinonouirechercheInternationa