Download or read book Contribution l analyse des signaux non stationnaires et ou non gaussiens written by Claude Jorand and published by . This book was released on 1994 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: LA TRANSFORMATION DE WIGNER-VILLE (TWV) EST UN OUTIL A PRESENT BIEN CONNU DANS L'ANALYSE DE SIGNAUX NON STATIONNAIRES. SA STRUCTURE NON LINEAIRE EST SOURCE D'INTERFERENCES ENTRE LES COMPOSANTES DU SIGNAL ANALYSE, CE QUI POSE UN PROBLEME LORS DE L'EXTRACTION DES INFORMATIONS PERTINENTES DANS L'IMAGE RESULTANTE. CONSIDEREE COMME UN PROCESSUS ALEATOIRE BIDIMENSIONNEL, CETTE IMAGE EST GENERALEMENT NON GAUSSIENNE. AINSI, CETTE TRANSFORMATION EST LE SIEGE DE TROIS NON-QUALITES: NON LINEARITE, DUE A L'OPERATEUR, NON STATIONNARITE ET NON GAUSSIANITE, QUI AFFECTENT LE SIGNAL ANALYSE OU PRODUIT. DANS CETTE ETUDE, NOUS NOUS INTERESSONS AUX DEUX NON-QUALITES LIEES AUX SIGNAUX: LA NON GAUSSIANITE, OU L'ON ABORDE CERTAINES TECHNIQUES UTILISANT LES STATISTIQUES D'ORDRE SUPERIEUR A DEUX, PUIS LA NON STATIONNARITE, QUI FAIT INTERVENIR LA TRANSFORMATION EN ONDELETTES COMME SECOND ROLE. ENFIN, DANS UN CADRE ETENDU DE LA TWV, ON RENCONTRE SIMULTANEMENT CES DEUX ATTRIBUTS. UN AUTRE ASPECT FONDAMENTAL DE CE TRAVAIL EST UNE CONTRIBUTION AU TRANSFERT DES TECHNIQUES DU TRAITEMENT DU SIGNAL VERS LE DOMAINE INDUSTRIEL, PAR LE DEVELOPPEMENT D'UN LOGICIEL D'ANALYSE NON STATIONNAIRE ET PAR SA MISE EN UVRE DANS L'ANALYSE VIBRATOIRE D'UN MOTEUR AUTOMOBILE

Download or read book Contribution l analyse de signaux non stationnaires written by Olivier Meste and published by . This book was released on 1992 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les signaux non-stationnaires qui font l'objet de la thèse sont d'abord envisagés d'un point de vue général et traités par une approche temps-fréquence ; on étudie ensuite des signaux non-stationnaires répétitifs en faisant intervenir la sommation synchrone. L'étude des signaux non-stationnaires par des représentations temps-fréquence permet le suivi de l'évolution spectrale du signal au cours du temps. Nous avons étudié et amélioré certaines méthodes appartenant à la classe de Cohen en les identifiant à des lissages de la transformée de Wigner-Ville et en étudiant leurs propriétés dans le plan fréquence-fréquence. Nous avons opposé à ces lissages linéaires, d'autres dont les paramètres varient soit en fonction du contenu spectral du signal en chaque point du plan temps-fréquence, soit en suivant une loi de variation définie à priori. La transformée en ondelette de Morlet, qui appartient à cette dernière classe, a été étudiée et une modification a été proposée. Le caractère répétitif de certains signaux d'application tels que les potentiels évoqués ou les signaux cardiaques, nous a amené à concevoir de nouvelles méthodes d'estimation de retards entre les réalisations du signal. La qualité des estimateurs proposés permet tout d'abord d'améliorer le signal moyen. De plus une estimation suffisamment précise de l'écart-type du jitter permet d'envisager un réhaussement du signal moyen par déconvolution. Une analyse temps-fréquence sur les signaux moyens permet alors de façon plus précise de déceler les détails permanents d'une réalisation à l'autre. L'amélioration des techniques de sommation synchrone rend possible, en réduisant le nombre de signaux sommés, de suivre des variations dynamiques réellement observées. Un algorithme adaptatif LMS a été proposé et son équivalence avec le moyennage à pondération exponentielle a été établie

Download or read book Contribution a l analyse de signaux non stationnaires application a l etude de signaux biomedicaux written by Olivier Meste and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Contribution l analyse de signaux non stationaires written by O. Meste and published by . This book was released on 1992 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Repr sentations temps fr quence des signaux non stationnaires written by François Auger and published by . This book was released on 1991 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ce mémoire concerne l'analyse temps-fréquence des signaux non-stationnaires. Après avoir montré la nécessité de ce type d'analyse, on s'intéresse aux distributions énergétiques de la classe de Cohen. Cette étude permet alors notamment de comparer ses différents éléments du point de vue de leurs propriétés théoriques, de la géométrie de leurs termes d'interférence et de leurs qualités descriptives, et de préciser les différents problèmes liés à l'obtention de leurs versions discrètes. On aborde ensuite les méthodes de représentation temps-fréquence paramétriques. On étudie tout d'abord les propriétés théoriques de certaines de ces représentations les plus classiques, en utilisant les mêmes critères que les représentations de la classe de Cohen, puis on s'intéresse aux possibilités de paramétrisation de ces dernières, et notamment de la représentation de Wigner-Ville. Enfin, on s'intéresse à différentes méthodes heuristiques d'élaboration de représentations temps-fréquence facilement lisibles et interprétables, en partant soit du spectrogramme, soit de la représentation de Wigner-Ville.

Download or read book M thodes de r allocation dans le plan temps fr quence pour l analyse et le traitement de signaux non stationnaires written by Eric Chassande-Mottin and published by . This book was released on 1998 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: LE CADRE DE CE TRAVAIL EST CELUI DE L'ANALYSE TEMPS-FREQUENCE (ET TEMPS-ECHELLE). PLUS PRECISEMENT, ON S'INTERESSE A LA METHODE DITE DE REALLOCATION, DESTINEE A AMELIORER LA LISIBILITE DES REPRESENTATIONS TEMPS-FREQUENCE. CETTE METHODE A ETE INTRODUITE AU COURS DES ANNEES 1970 ET REACTUALISEE RECEMMENT. ELLE REPOSE SUR L'INTERVENTION D'UN CHAMP DE VECTEURS (DE REALLOCATION) ADEQUAT QUI DEPLACE LES VALEURS DE LA DISTRIBUTION TEMPS-FREQUENCE DE TELLE SORTE QU'AU FINAL, LA LECTURE EN SOIT SIMPLIFIEE. BIEN QUE LE PRINCIPE DE REALLOCATION SOIT BIEN CONNU, LES CONSEQUENCES DE SA MISE EN UVRE LE SONT MOINS. LE PREMIER OBJECTIF DE CETTE THESE EST D'APPORTER DES ELEMENTS DE REPONSE A CETTE QUESTION. ON EFFECTUE PAR EXEMPLE LA DESCRIPTION STATISTIQUE DU CHAMP DES VECTEURS DE REALLOCATION (DU SPECTROGRAMME) LORSQUE DU BRUIT (GAUSSIEN) SE SUPERPOSE AU SIGNAL (SUPPOSE DETERMINISTE). COMPTE TENU DE CES INFORMATIONS, NOUS NOUS SOMMES ENSUITE ATTACHES A AMELIORER LA METHODE ORIGINALE : DANS LE CAS DE MELANGE SIGNAL ET BRUIT, ON PROPOSE UNE METHODE DE SUPERVISION QUI DECIDE EN CHAQUE POINT DU PLAN TEMPS-FREQUENCE S'IL EST OPPORTUN DE FAIRE LA REALLOCATION. NOUS MONTRONS EGALEMENT QUE LA METHODE DE REALLOCATION PEUT SE METTRE EN PRATIQUE AU-DELA D'UN BUT D'ANALYSE ET PRENDRE PART DANS UNE CHAINE DE TRAITEMENT DU SIGNAL : EN S'APPUYANT SUR UNE DESCRIPTION GEOMETRIQUE PRECISE DES CHAMPS DE VECTEURS DE REALLOCATION, ON INTRODUIT UNE NOUVELLE METHODE DE REALLOCATION DITE DIFFERENTIELLE A PARTIR DE LAQUELLE IL DEVIENT POSSIBLE DE PARTAGER LE PLAN TEMPS-FREQUENCE EN REGIONS QUE L'ON ASSOCIE A UNE COMPOSANTE DU SIGNAL. CETTE PARTITION PEUT ETRE DONC VUE A POSTERIORI COMME LA DECOMPOSITION DU SIGNAL EN COMPOSANTES MODULEES EN AMPLITUDE ET/OU FREQUENCE. NOUS MONTRONS EGALEMENT QUE, GRACE A LEUR BONNE PROPRIETE DE LOCALISATION, LES DISTRIBUTIONS TEMPS-FREQUENCE REALLOUEES PEUVENT ETRE UTILES POUR DES PROBLEMES DE DETECTION DE CHIRPS, COMME PAR EXEMPLE CELUI DES ONDES GRAVITATIONNELLES.

Download or read book Contributions l analyse spectrale des processus non stationnaires written by Dominique Dehay and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Representations temps frequence des signaux non stationnaires synthese et contribution written by François Auger (enseignant-chercheur en génie électrique).) and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analyse spectrale de signaux non stationnaires written by Michel Jacob and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Wigner Distribution written by W. Mecklenbräuker and published by . This book was released on 1997-10-08 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seven contributions discuss in depth several aspects of one of the methods for representing both the frequency domain and the temporal localization of signals, which has tremendous importance in signal analysis and processing. Among them are properties like positivity, spread, and interference-term geometry; signal synthesis methods and their application to signal design, time- frequency filtering, and signal separation; the analysis of non- stationary random processes; singular value decompositions and their application to detection and classification; and optical applications of the Wigner Distribution. Also includes a bibliography of published works on the subject from 1985 to 1992. Annotation copyrighted by Book News, Inc., Portland, OR

Download or read book Wavelets and Their Applications written by J.S. Byrnes and published by Springer Science & Business Media. This book was released on 1994-08-31 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is probably true quite generally that in the history of human thinking the most fruitful developments frequently take place at those points where two different lines of thought meet. Hence, if they actually meet, that is, if they are at least so much related to each other that a real interaction can take place, then one may hope that new and interesting developments may follow. Werner Heisenberg This volume contains papers presented at the August 1992 NATO Advanced Study Institute on Wavelets and Their Applications. The conference was held at the beautiful Il Ciocco resort near Lucca, in the glorious Tuscany region of northern Italy. Once again we gathered at this idyllic spot to explore and extend the reciprocity between mathematics and engineering. The dynamic interaction between world-renowned scientists from the usu ally disparate communities of pure mathematicians and applied scientists, which occurred at our 1989 and 1991 ASI's, continued at this meeting. Wavelet theory and technology is in an important growth stage at which theoretical and practical results are being compared with existing methods. There have been spectacular wavelet successes and sobering comparisons with traditional ideas-but still there is a wide expanse of scientific problems to explore. Since these problems lie at the forefront of both pure mathematics and applied science, our NATO ASI was especially pertinent at this time.

Download or read book Underwater Acoustic Data Processing written by Y. T. Chan and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the papers that were accepted for presentation at the 1988 NATO Advanced Study Institute on Underwater Acoustic Data Processing, held at the Royal Military College of Canada from 18 to 29 July, 1988. Approximately 110 participants from various NATO countries were in attendance during this two week period. Their research interests range from underwater acoustics to signal processing and computer science; some are renowned scientists and some are recent Ph.D. graduates. The purpose of the ASI was to provide an authoritative summing up of the various research activities related to sonar technology. The exposition on each subject began with one or two tutorials prepared by invited lecturers, followed by research papers which provided indications of the state of development in that specific area. I have broadly classified the papers into three sections under the titles of I. Propagation and Noise, II. Signal Processing and III. Post Processing. The reader will find in Section I papers on low frequency acoustic sources and effects of the medium on underwater acoustic propagation. Problems such as coherence loss due to boundary interaction, wavefront distortion and multipath transmission were addressed. Besides the medium, corrupting noise sources also have a strong influence on the performance of a sonar system and several researchers described methods of modeling these sources.

Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.

Download or read book Dynamique Non lin aire Et Le Chaos written by and published by . This book was released on 1993 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modern Electrocardiography written by Eugene Lepeschkin and published by . This book was released on 1951 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantum Mechanics Volume 3 written by Claude Cohen-Tannoudji and published by John Wiley & Sons. This book was released on 2019-12-16 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new, third volume of Cohen-Tannoudji's groundbreaking textbook covers advanced topics of quantum mechanics such as uncorrelated and correlated identical particles, the quantum theory of the electromagnetic field, absorption, emission and scattering of photons by atoms, and quantum entanglement. Written in a didactically unrivalled manner, the textbook explains the fundamental concepts in seven chapters which are elaborated in accompanying complements that provide more detailed discussions, examples and applications. * Completing the success story: the third and final volume of the quantum mechanics textbook written by 1997 Nobel laureate Claude Cohen-Tannoudji and his colleagues Bernard Diu and Franck Laloë * As easily comprehensible as possible: all steps of the physical background and its mathematical representation are spelled out explicitly * Comprehensive: in addition to the fundamentals themselves, the books comes with a wealth of elaborately explained examples and applications Claude Cohen-Tannoudji was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris where he also studied and received his PhD in 1962. In 1973 he became Professor of atomic and molecular physics at the Collège des France. His main research interests were optical pumping, quantum optics and atom-photon interactions. In 1997, Claude Cohen-Tannoudji, together with Steven Chu and William D. Phillips, was awarded the Nobel Prize in Physics for his research on laser cooling and trapping of neutral atoms. Bernard Diu was Professor at the Denis Diderot University (Paris VII). He was engaged in research at the Laboratory of Theoretical Physics and High Energy where his focus was on strong interactions physics and statistical mechanics. Franck Laloë was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris. His first assignment was with the University of Paris VI before he was appointed to the CNRS, the French National Research Center. His research was focused on optical pumping, statistical mechanics of quantum gases, musical acoustics and the foundations of quantum mechanics.

Download or read book Belief Functions Theory and Applications written by Sébastien Destercke and published by Springer. This book was released on 2018-09-07 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 5th International Conference on Belief Functions, BELIEF 2018, held in Compiègne, France, in September 2018.The 33 revised regular papers presented in this book were carefully selected and reviewed from 73 submissions. The papers were solicited on theoretical aspects (including for example statistical inference, mathematical foundations, continuous belief functions) as well as on applications in various areas including classification, statistics, data fusion, network analysis and intelligent vehicles.