3,512 research outputs found
Nilpotent polynomials approach to four-qubit entanglement
We apply the general formalism of nilpotent polynomials [Mandilara et al,
Phys. Rev. A 74, 022331 (2006)] to the problem of pure-state multipartite
entanglement classification in four qubits. In addition to establishing contact
with existing results, we explicitly show how the nilpotent formalism naturally
suggests constructions of entanglement measures invariant under the required
unitary or invertible class of local operations. A candidate measure of
fourpartite entanglement is also suggested, and its behavior numerically tested
on random pure states.Comment: 11 pages, 1 figure. Finalised versio
Une synthèse des modèles de représentation des connaissances à base de Graphes Conceptuels et OWL
Nous présentons et comparons deux approches de modélisation, formelles et concrètes, pour représenter et manipuler des connaissances d’un domaine. Le modèle des graphes conceptuels permet de modéliser des connaissances en terme de graphes, basés sur un support. Cette approche de modélisation est intensionnelle, est munie d’une sémantique en logique du premier ordre, et fait l’hypothèse d’un monde fermé pour ses raisonnements. Le langage OWL permet de décrire des ontologies et des faits sur le Web, suivant une approche de modélisation extensionnelle. Il possède une sémantique issue des logiques de descriptions, et fait l’hypothèse d’un monde ouvert pour ses raisonnements
Systematic Evaluation of Deep Learning Models for Failure Prediction
With the increasing complexity and scope of software systems, their
dependability is crucial. The analysis of log data recorded during system
execution can enable engineers to automatically predict failures at run time.
Several Machine Learning (ML) techniques, including traditional ML and Deep
Learning (DL), have been proposed to automate such tasks. However, current
empirical studies are limited in terms of covering all main DL types --
Recurrent Neural Network (RNN), Convolutional Neural network (CNN), and
transformer -- as well as examining them on a wide range of diverse datasets.
In this paper, we aim to address these issues by systematically investigating
the combination of log data embedding strategies and DL types for failure
prediction. To that end, we propose a modular architecture to accommodate
various configurations of embedding strategies and DL-based encoders. To
further investigate how dataset characteristics such as dataset size and
failure percentage affect model accuracy, we synthesised 360 datasets, with
varying characteristics, for three distinct system behavioral models, based on
a systematic and automated generation approach. Using the F1 score metric, our
results show that the best overall performing configuration is a CNN-based
encoder with Logkey2vec. Additionally, we provide specific dataset conditions,
namely a dataset size >350 or a failure percentage >7.5%, under which this
configuration demonstrates high accuracy for failure prediction
Natural occurrence of entomopathogenic nematodes (Rhabditida : Steinernematidae and Heterorhabditidae) in Guadeloupe islands
Des prospections ont été réalisées sur 538 sites en Guadeloupe (Grande Terre, Basse Terre) et dans ses dépendances (Marie-Galante, La Désirade, Petite Terre, Les Saintes, Saint-Barthélémy, Saint-Martin) pour rechercher des nématodes entomopathogènes par la technique du piège à insecte (#FGalleria mellonella (97%) et l'un d'eux un #Steinernema (88%) et #H. bacteriophora appartient sans doute à une nouvelle espèce en cours d'étude. Les nématodes ont été isolés en zone côtière (91,4%), en zone tropicale de basse (5,7%) et de moyenne altitude (2,9%). Aucun nématode n'a été trouvé en zone montagneuse. (Résumé d'auteur
Hamilton Jacobi Bellman equations in infinite dimensions with quadratic and superquadratic Hamiltonian
We consider Hamilton Jacobi Bellman equations in an inifinite dimensional
Hilbert space, with quadratic (respectively superquadratic) hamiltonian and
with continuous (respectively lipschitz continuous) final conditions. This
allows to study stochastic optimal control problems for suitable controlled
Ornstein Uhlenbeck process with unbounded control processes
Analytical solution of a model for complex food webs
We investigate numerically and analytically a recently proposed model for
food webs [Nature {\bf 404}, 180 (2000)] in the limit of large web sizes and
sparse interaction matrices. We obtain analytical expressions for several
quantities with ecological interest, in particular the probability
distributions for the number of prey and the number of predators. We find that
these distributions have fast-decaying exponential and Gaussian tails,
respectively. We also find that our analytical expressions are robust to
changes in the details of the model.Comment: 4 pages (RevTeX). Final versio
From organic semiconductors to marine antifouling coatings: how electronic strategies can control bacteria development
A bipartite class of entanglement monotones for N-qubit pure states
We construct a class of algebraic invariants for N-qubit pure states based on
bipartite decompositions of the system.
We show that they are entanglement monotones, and that they differ from the
well know linear entropies of the sub-systems. They therefore capture new
information on the non-local properties of multipartite systems.Comment: 6 page
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