Sliding mode reference conditioning for path following applied to an AUV

This work presents a dynamic model for an autonomous underwater vehicle (AUV), a validation of this model together with the simulator obtained from its application and an implementation of sliding mode reference conditioning (SMRC). This last technique is proposed in order to follow a path at maximum speed with bounded errors in a dynamical framework, taking care of the saturation in systems actuators, resulting in an improvement of the path tracking time.Fil: Rosendo, Juan Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Clement, Benoit. Centre National de la Recherche Scientifique; Francia. Laboratoire Des Sciences Et Techniques de L'information, de la Communication Et de la Connaissance; FranciaFil: Garelli, Fabricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; Argentin

Random cubic planar graphs revisited

The goal of our work is to analyze random cubic planar graphs according to the uniform distribution. More precisely, let G be the class of labelled cubic planar graphs and let gn be the number of graphs with n verticesPostprint (author's final draft

Enumeration of labeled 4-regular planar graphs

© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In this extended abstract, we present the first combinatorial scheme for counting labeled 4-regular planar graphs through a complete recursive decomposition. More precisely, we show that the exponential generating function counting labeled 4-regular planar graphs can be computed effectively as the solution of a system of equations. From here we can extract the coefficients by means of algebraic calculus. As a by-product, we can also compute the algebraic generating function counting labeled 3-connected 4-regular planar maps.Peer ReviewedPostprint (author's final draft

Enumeration of labelled 4-regular planar graphs II: asymptotics

This work is a follow-up of the article (Noy et al., 2019), where the authors solved the problem of counting labelled 4-regular planar graphs. In this paper, we obtain a precise asymptotic estimate for the number of labelled 4-regular planar graphs on vertices. Our estimate is of the form , where is a constant and is the radius of convergence of the generating function , and conforms to the universal pattern obtained previously in the enumeration of several classes of planar graphs. In addition to analytic methods, our solution needs intensive use of computer algebra in order to deal with large systems of multivariate polynomial equations. We also obtain asymptotic estimates for the number of 2- and 3-connected 4-regular planar graphs, and for the number of 4-regular simple maps, both connected and 2-connected.Peer ReviewedPostprint (author's final draft

A Way to Automatically Enrich Biomedical Ontologies

International audienceBiomedical ontologies play an important role for information extraction in the biomedical domain. We present a workflow for updating automatically biomedical ontologies, composed of four steps. We detail two contributions concerning the concept extraction and semantic linkage of extracted terminology

Extraction automatique de termes combinant différentes informations

National audiencePour une communauté, la terminologie est essentielle car elle permet de décrire, échanger et récupérer les données. Dans de nombreux domaines, l'explosion du volume des données textuelles nécessite de recourir à une automatisation du processus d'extraction de la terminologie, voire son enrichissement. L'extraction automatique de termes peut s'appuyer sur des approches de traitement du langage naturel. Des méthodes prenant en compte les aspects linguistiques et statistiques proposées dans la littérature, résolvent quelques problèmes liés à l'extraction de termes tels que la faible fréquence, la complexité d'extraction de termes de plusieurs mots, ou l'effort humain pour valider les termes candidats. Dans ce contexte, nous proposons deux nouvelles mesures pour l'extraction et le "ranking" des termes formés de plusieurs mots à partir des corpus spécifiques d'un domaine. En outre, nous montrons comment l'utilisation du Web pour évaluer l'importance d'un terme candidat permet d'améliorer les résultats en terme de précision. Ces expérimentations sont réalisées sur le corpus biomédical GENIA en utilisant des mesures de la littérature telles que C-value

Biomedical Terminology Extraction: A new combination of Statistical and Web Mining Approaches

International audienceThe objective of this work is to combine statistical and web mining methods for the automatic extraction, and ranking of biomedical terms from free text. We present new extraction methods that use linguistic patterns specialized for the biomedical field, and use term extraction measures, such as C-value, and keyword extraction measures, such as Okapi BM25, and TFIDF. We propose several combinations of these measures to improve the extraction and ranking process and we investigate which combinations are more relevant for different cases. Each measure gives us a ranked list of candidate terms that we finally re-rank with a new web-based measure. Our experiments show, first that an appropriate harmonic mean of C-value used with keyword extraction measures offers better precision results than used alone, either for the extraction of single-word and multi-words terms; second, that best precision results are often obtained when we re-rank using the web-based measure. We illustrate our results on the extraction of English and French biomedical terms from a corpus of laboratory tests available online in both languages. The results are validated by using UMLS (in English) and only MeSH (in French) as reference dictionary

Prédiction de la polysémie pour un terme biomédical

National audiencePolysemy is the capacity for a term to have multiple meanings. Polysemy prediction is a first step for Word Sense Induction (WSI), which allows to find different meanings for a term, as well as for Information Extraction (IE) systems. In addition, the polysemy detection is important for building and enriching terminologies and ontologies. In this paper, we present a novel approach to detect if a biomedical term is polysemic or not, with the long term goal of enriching biomedical ontologies after disambiguation of candidate terms. This approach is based on meta-learning techniques, more precisely on meta-features. We propose the definition of novel meta-features, extracted directly from the text dataset, as well as from a graph of coc- current terms. Our method obtains very good results, with an Accuracy and F-mesure of 0.978.La polysémie est la caractéristique d'un terme à avoir plusieurs significations. La prédiction de la polysémie est une première étape pour l'Induction de Sens (IS), qui permet de trouver des significations différentes pour un terme, ainsi que pour les systèmes d'extraction d'information. En outre, la détection de la polysémie est importante pour la construction et l'en-richissement de terminologies et d'ontologies. Dans cet article, nous présentons une nouvelle approche pour prédire si un terme biomédical est polysémique ou non, avec l'objectif à long terme d'enrichir les ontologies biomédicales après avoir désambiguïser les termes candidats. Cette approche est basée sur l'utilisation de techniques de méta-apprentissage, plus précisé-ment sur des méta-descripteurs. Dans ce contexte, nous proposons la définition de nouveaux méta-descripteurs, extraits directement du texte, et d'un graphe de co-occurrences des termes. Notre méthode donne des résultats très satisfaisants, avec une exactitude et F-mesure de 0.978

Técnicas de metrología óptica basadas en fotónica de microondas

Esta tesis presenta una serie de técnicas de metrología óptica basadas en fotónica de microondas (MWP), cuya incorporación permite la mejora de ciertas figuras de mérito con respecto a sus equivalentes puramente fotónicos en el ámbito de la metrología óptica y de la interrogación de sensores de fibra óptica (OFS). Tras una introducción donde se describen algunos de los tipos de OFS más relevantes y los cuatro principales métodos de reflectometría óptica, se resumen las publicaciones que forman parte del compendio de la presente tesis. Estas se han dividido en aquellas que presentan técnicas basadas en reflectometría óptica incoherente dispersiva en el dominio de la frecuencia (DI-OFDR), o sistemas con mejoras que pueden ser empleadas en DI-OFDR, y aquellas que han buscado y estudiado las aplicaciones metrológicas de los bucles desplazadores de frecuencia (FSL). El primer grupo de técnicas hace referencia a sistemas basados en reflectometría óptica incoherente en el dominio de la frecuencia (I-OFDR) donde la inclusión de un elemento dispersivo en el circuito óptico permite la incorporación de nuevas funcionalidades. En particular, la medición de desplazamiento de la longitud de onda de reflectores de banda estrecha mediante la detección del retraso de grupo diferencial de ondas moduladas. El segundo se refiere al estudio teórico y experimental de peines de frecuencia generados por lazos de fibra amplificados que incluyen un elemento desplazador de frecuencia, y que permiten la generación de un amplio conjunto de formas de onda ópticas de interés en, entre otros ámbitos, aplicaciones metrológicas. Por una parte, las publicaciones relacionadas con DI-OFDR han consistido en: el desarrollo de un método de interrogación de redes de Bragg en fibra (FBG) mediante una fuente de doble longitud de onda; la minimización del número de puntos de interrogación en frecuencia en sistemas DI-OFDR adaptada a una topología de reflectores equiespaciados, así como el desarrollo de un método basado únicamente en medidas de potencia; y la implementación de un sistema con conversión electroóptica descendente de frecuencia y detección a frecuencia intermedia para la realización de medidas reflectométricas tanto distribuidas como puntuales y, en este caso, con selectividad en longitud de onda. Entre otras ventajas, estos sistemas han permitido la interrogación de FBG con resolución picométrica y alta eficiencia en potencia; velocidades de interrogación de arrays FBG de hasta 10 μs por elemento sensor; y la detección de eventos reflexivos discretos con reflectividades de hasta 90 dB y de retrodispersión Rayleigh en banda C en fibra monomodo estándar; respectivamente. Por otra parte, las publicaciones relacionadas con los FSL se han centrado, respectivamente, en la aplicación de las formas de onda ópticas de tipo chirp generadas por estos dispositivos para la medición de distancia con resolución milimétrica por compresión de digital de pulso, aprovechando para ello su alto producto tiempo-ancho de banda ( 200), y en la descripción teórica de dichas formas de onda. Empleando una descripción del campo generado por los FSL basada en una analogía con la óptica difractiva, se han descrito nuevas propiedades de los pulsos tipo chirp generados por FSL. En concreto, la existencia de captura de fase entre distintos pulsos, la presencia de desviaciones de la linealidad del chirp y la comprobación experimental de la coincidencia entre las fases Talbot generadas en FSL bajo condiciones fraccionales y las secuencias de fase perfecta de Gauss. Los resultados de esta segunda parte de la tesis muestran, además de un buen acuerdo del modelo teórico con los pulsos medidos, la viabilidad del empleo de FSL para medición de distancia láser con compresión digital de pulsos, obteniéndose tasas de compresión y de repetición de 150 y 80 MHz, respectivamente, y un ancho de banda de 20 GHz.This thesis presents several techniques of optical metrology based on Microwave Photonics (MWP), whose incorporation allows for improving some figures of merit with respect to its purely photonic equivalents in the fields of optical metrology and interrogation of optical fiber sensors (OFS). After an introduction where some of the most relevant types of OFSs and the four main methods of optical reflectometry are described, the publications that form the compendium of this thesis are summarized. These have been divided in those which present techniques based on dispersive incoherent optical frequency-domain reflectometry (DI-OFDR), or systems with improvements that can be employed in DI-OFDR, and those which have searched and studied the metrology applications of the frequency shifting loops (FSL). The first group of techniques refers to systems based on incoherent optical frequency-domain reflectometry (I-OFDR) where the inclusion of a dispersive element in the optical circuit allows for incorporating new functionalities. In particular, measuring wavelength shiftings in narrow band reflectors by detecting the differential group delay of modulated waves. The second refers to the theoretical and experimental study of frequency combs generated by amplified fiber loops that include a frequency shifting loop, and that allow for generating a wide group of optical waveforms of interest in, among other fields, metrology applications. On the one hand, the publications related to DI-OFDR have consisted in: the development of an interrogation method of fiber Bragg gratings (FBG) by a dual-wavelength source; the minimization of the number of interrogation points in frequency in DI-OFDR systems adapted to a topology of equally-spaced reflectors, as well as the development of a method based only in power measurements; and the implementation of a system with electro-optic downconversion and detection at intermediate frequency for conducting reflectometric measurements either single-point or distributed and, in this case, with wavelength selectivity. Among other advantages, these systems have allowed for interrogating FBGs with picometric resolution and high power efficiency, interrogating FBG arrays with speeds up to 10 μs per sensing element, and detecting discrete reflective events with reflectivities up to 90 dB and Rayleigh backscattering in C band in standard monomode fiber; respectively. On the other hand, the publications related to FSLs have been focused, respectively, on the application of the chirped optical waveforms generated by these devices for distance measuring with millimetric resolution by digital pulse compression, taking advantage of its high time-bandwidth product ( 200), and the theoretical description of these waveforms. Using a description of the field generated by the FSLs based on an analogy with diffractive optics, new properties of the chirped pulses generated by FSLs have been described. In particular, the existence of phase capture between different pulses, the presence of chirp linearity deviations, and the experimental verification of the coincidence between the Talbot phases generated in FSLs and the Gauss perfect phase sequences. The results of this second part of the thesis show, besides a good agreement between the theoretical model and the measured pulses, the feasibility of using FSLs for laser dis- tance measuring with digital pulse compression, obtaining compression and repetition rates of 150 and 80 MHz, respectively, and a 20 GHz bandwidth