Search results for "Opera"
showing 10 items of 8665 documents
Semantic-based Merging of RSS Items
2009
Merging XML documents can be of key importance in several applications. For instance, merging the RSS news from same or different sources and providers can be beneficial for end-users in various scenarios. In this paper, we address this issue and explore the relatedness measure between RSS elements. We show here how to define and compute exclusive relations between any two elements and provide several predefined merging operators that can be extended and adapted to human needs. We also provide a set of experiments conducted to validate our approach. © Springer Science+Business Media, LLC 2009.
Qualifying semantic graphs using model checking
2011
International audience; Semantic interoperability problems have found their solutions using languages and techniques from the Semantic Web. The proliferation of ontologies and meta-information has improved the understanding of information and the relevance of search engine responses. However, the construction of semantic graphs is a source of numerous errors of interpretation or modeling and scalability remains a major problem. The processing of large semantic graphs is a limit to the use of semantics in current information systems. The work presented in this paper is part of a new research at the border of two areas: the semantic web and the model checking. This line of research concerns t…
Recursive estimators 2
1991
In this paper the techniques for recursive estimation of linear model are extended to non-spherical disturbances. First we present the recursive formulae of generalized least squares. The recurrence relation for the residual sum of squares are derived. We show in the second part of the paper a recursive formulae of generalized instrumental variables.
Quasi order, pseudo order and not order
1995
This study, after having presented the structure of total semi-order and that of pseudo-order one, presents a new preference structure called non order. This one generalizes both the semi-order structure and the pseudo-order one. The details analysis are based on the usual concepts of the relationnal approach of preference modelling and on some new concepts and principles which fit the imprecise context. These new principles are : imprecise discriminant power, imprecise transitivity, imprecise intransitivity and generalized limited comparability. The new concepts are : preference relationnal constituent and preference relationnal state.
Distribution of power and social utility under nonadditive aggregation rules
1992
In this paper, we try first to shift the problem onto the agents. We want actually to consider some methods for passing from coalitions to lotteries over coalitions. These methods are associated with a function that could correspond to a social utility function. It gives the level of satisfaction coming from the anticipated "consumption" of a subset of alternatives (goods, candidates,..) by a coalition. Second, we want to define the distributions of power regardless of those two-element feasible sets which characterize preferences in basic models on one side, and we try to exhibit a theoretical relation between the basic Barberà & Sonnenschein’s model and ours thanks to the Choice Axiom of …
De l'effet d'imprécision et du paradoxe de la non ponctualité des seuils vers la définition de quelques concepts et principes de modélisation des pré…
1994
(EN) This survey deals with conceptual and theoritical basis of imprecise preference modelling. From the establishment of non-punctuality of the imprecise preference threshold, imprecise discrimination power is set. This involves that the modelling preference relation tool is composite. Which allows a generalization of the limited comparability principle and an introduction of new concepts which adapt to this theoritical framework.(FR) Ce travail pose les fondements conceptuels et théoriques de la modélisation des préférences imprécises. A partir du constat de non ponctualité des seuils de préférence, il pose le principe du pouvoir discriminant imprécis. Il en résulte que l'outil relationne…
Interior Eigenvalue Density of Jordan Matrices with Random Perturbations
2017
International audience; We study the eigenvalue distribution of a large Jordan block subject to a small random Gaussian perturbation. A result by E. B. Davies and M. Hager shows that as the dimension of the matrix gets large, with probability close to 1, most of the eigenvalues are close to a circle.We study the expected eigenvalue density of the perturbed Jordan block in the interior of that circle and give a precise asymptotic description.; Nous étudions la distribution de valeurs propres d’un grand bloc de Jordan soumis à une petite perturbation gaussienne aléatoire. Un résultat de E. B. Davies et M. Hager montre que quand la dimension de la matrice devient grande, alors avec probabilité…
Théorie de système et séries temporelles
1994
The aim of this paper is to present a different representation of state space models, (innovation state space representation) which is relatively new and apparently unknown in the economics and econometrics literature and to describe some of its properties. state space representation is a very flexible form for time series and the approach taken in this paper therefore allows a broad class of models it does not impose a priori the decomposition of data series into trend and cycle
Continuous optimal control sensitivity analysis with AD
2000
In order to apply a parametric method to a minimum time control problem in celestial mechanics, a sensitivity analysis is performed. The analysis is continuous in the sense that it is done in the infinite dimensional control setting. The resulting sufficient second order condition is evaluated by means of automatic differentiation, while the associated sensitivity derivative is computed by continuous reverse differentiation. The numerical results are given for several examples of orbit transfer, also illustrating the advantages of automatic differentiation over finite differences for the computation of gradients on the discretized problem.
Sensitivity analysis for time optimal orbit transfer
2001
The minimum time transfer of a satellite around the Earth is studied. In order to deal numerically with low thrusts, a new method is introduced: Based on a so-called noncontrollability function, the technique treats the ha1 time as a parameter. The properties of the method arc studied by means of an infinite dimensional sensitivity analysis. The numerical results obtained by this approach for very low thrusts are given