Download or read book Etude des syst mes actifs de contr le de l acoustique des salles written by Olivier Vuichard and published by . This book was released on 1997 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL S'INTERESSE AUX SYSTEMES ELECTROACOUSTIQUES DE CONTROLE DE LA REVERBERATION UTILISES DANS LES SALLES DE SPECTACLES AFIN DE MODULER LEURS CARACTERISTIQUES ACOUSTIQUES SELON LE TYPE DE SPECTACLE. IL EST CENTRE SUR L'APPLICATION DU MUR ACTIF A CE TYPE DE SYSTEMES. UNE MISE EN OEUVRE SIMPLIFIEE, FAISANT APPEL A UN DECOUPLAGE ACOUSTIQUE DE L'ONDE DIRECTE DU HAUT-PARLEUR VERS LE MICROPHONE ASSOCIE SITUE A PROXIMITE, EST PRESENTEE. LE SYSTEME BASE SUR CE PRINCIPE EST APPELE SYSTEME REGENERATIF A REACTION QUASI-LOCALE, ET LES RESULTATS OBTENUS DANS TROIS SALLES OU IL FUT INSTALLE PERMETTENT DE LE VALIDER. PARALLELEMENT, DES DEVELOPPEMENTS THEORIQUES ET NUMERIQUES SONT PRESENTES. ILS VISENT A UNIFIER ET CLARIFIER LES DIFFERENTES FORMULATIONS RENCONTREES DANS LA LITTERATURE COURANTE, ET A DEVELOPPER CERTAINS POINTS CONCERNANT EN PARTICULIER LA POSITION DES MICROPHONES PAR RAPPORT AUX HAUT-PARLEURS DU SYSTEME ET PAR RAPPORT A LA SCENE, OU L'UTILISATION DE REVERBERATION ELECTRONIQUE. ILS NOUS PERMETTENT D'EXPLIQUER DANS QUELLES LIMITES PEUVENT FONCTIONNER LES DIFFERENTES FAMILLES DE SYSTEMES, ET NOTAMMENT LES SYSTEMES A REACTION QUASI-LOCALE. CERTAINS ASPECTS CONNEXES A CES SYSTEMES SONT EGALEMENT DEVELOPPES. UNE ETUDE MONTRE QUE LE CONTROLE DE L'ENERGIE PRECOCE PAR UN SYSTEME DE REVERBERATION ASSISTEE EST RELATIVEMENT LIMITE (UNE AUGMENTATION MAXIMALE DE 10% DE L'INTELLIGIBILITE PEUT ETRE OBTENUE SOUS CERTAINES CONDITIONS). UN JEU D'INDICES PERMETTANT DE CARACTERISER OBJECTIVEMENT LA COLORATION DU SON LIE AU REBOUCLAGE ACOUSTIQUE EST PROPOSE, ET SA PERTINENCE EST VALIDEE PAR UNE ETUDE PERCEPTIVE. ENFIN, DE NOMBREUX ASPECTS PRATIQUES CONCERNANT L'INSTALLATION D'UN SYSTEME SONT DISCUTES. UN PANORAMA DES DIFFERENTES METHODES DE SIMULATION DE SALLES EQUIPEES D'UN SYSTEME DE REVERBERATION ASSISTEE EST EXPOSE. UN SIMULATEUR, DIT EXACT, A ETE DEVELOPPE. IL PERMET D'APPRECIER SUBJECTIVEMENT (AURALISATIONS) L'INSTALLATION D'UN SYSTEME DANS UNE SALLE EXISTANTE OU EN PROJET.
Download or read book Filtrage adaptatif applique au controle actif de l acoustique d une salle written by Zhen Ren and published by . This book was released on 1995 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE THESE CONTRIBUE A L'ETUDE DU CONTROLE ACTIF DE L'ACOUSTIQUE D'UNE SALLE EN UTILISANT DES SYSTEMES ELECTROACOUSTIQUES. L'IDEE ESSENTIELLE EST DE CONSTITUER DES MURS ACTIFS PAR UN ASSEMBLAGE DE CELLULES ELEMENTAIRES AFIN DE CHANGER LA REPARTITION ENERGETIQUE D'UNE SALLE. CHAQUE CELLULE DOIT PERMETTRE DE REGLER LE NIVEAU DE RETOUR DU HAUT-PARLEUR A UNE VALEUR DESIREE TOUT EN CONTROLANT LA STABILITE DU SYSTEME. UN ENSEMBLE DES CELLULES CONVENABLEMENT COUPLEES POURRA ALORS CONTROLER LE COEFFICIENT DE REFLEXION GLOBALE D'UN MUR ACTIF. PAR CONSEQUENT, LE TEMPS DE REVERBERATION ET LES PREMIERES REFLEXIONS D'UNE SALLE SERONT CONTROLES. UNE STRUCTURE D'UNE CELLULE ELEMENTAIRE DU SYSTEME DE MUR ACTIF EST PROPOSEE. DEUX FILTRES ADAPTATIFS SONT INTRODUITS POUR CONTROLER RESPECTIVEMENT LA STABILITE ET LE NIVEAU DE RETOUR D'UNE CELLULE DU SYSTEME. LES ALGORITHMES DE CALCUL DES DEUX FILTRES ADAPTATIFS SONT PRESENTES. LES PRINCIPAUX RESULTATS THEORIQUES SONT ILLUSTRES SUR DES SIMULATIONS. LE PROBLEME DE L'ORGANISATION DES CELLULES D'UN SYSTEME DE MUR ACTIF EN VUE DE RECONSTITUER UN CHAMP SONORE LE PLUS NATUREL POSSIBLE A ETE ABORDE. LES RESULTATS DE SIMULATION DE DEUX TYPES DE MURS (UN MUR ACTIF ET UN VRAI MUR DE MEME DIMENSION) ONT ETE COMPARES. LA FAISABILITE PRATIQUE EST DISCUTEE. UNE REALISATION TEMPS REEL D'UNE CELLULE A ETE IMPLANTEE SUR UNE CARTE SPECIALISEE (TMS 320C30). LES PERFORMANCES DU PROTOTYPE D'UNE CELLULE SONT TESTEES NOTAMMENT EN CE QUI CONCERNE LA STABILITE D'UN COUPLE MICROPHONE HAUT-PARLEUR. UN CALCUL ACOUSTIQUE THEORIQUE SOUS DES HYPOTHESES SIMPLIFICATRICES EST DONNE. NOUS POUVONS DONC EVALUER EN FONCTION DU NOMBRE DE CELLULES LE TEMPS DE REVERBERATION D'UNE SALLE A PARTIR DE CARACTERISTIQUES MESUREES DANS CETTE SALLE. ENFIN UN PREMIER PROTOTYPE SIMPLIFIE D'UN MUR ACTIF EST PRESENTE
Download or read book QUALIFICATION D UN SYSTEME DE CONTROLE ACOUSTIQUE STRUCTURAL ACTIF written by Frédéric Dahan and published by . This book was released on 1996 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: DANS LE DOMAINE DE LA PREDICTION, LA MODELISATION NUMERIQUE EN VIBRO-ACOUSTIQUE (EN REGIME HARMONIQUE) EST EXPLOITEE POUR ETUDIER LES SYSTEMES D'ABSORPTION ACTIVE. L'ETUDE PORTE SUR LE CONTROLE ACOUSTIQUE STRUCTURAL QUI AGIT SUR LA STRUCTURE A L'ORIGINE DU BRUIT A SUPPRIMER. OR, CETTE METHODE CONDUIT SOUVENT A UNE AMPLIFICATION DES VIBRATIONS STRUCTURALES (EFFET SPILLOVER). COMMENT DEFINIR ET QUALIFIER UN DISPOSITIF ACTIONNEURS/CAPTEURS QUI, A PARTIR D'UN CONTROLE LOCAL PAR ANTICIPATION DE TYPE LMS, ATTENUE EFFICACEMENT LE RAYONNEMENT GLOBAL SANS EFFET SPILLOVER ? EN PREMIER LIEU, NOUS MONTRONS QUE LA SENSIBILITE DES MECANISMES DE CONTROLE S'OPPOSE A LA RESOLUTION MODALE DU PROBLEME. EN REVANCHE, UNE APPROCHE GLOBALE PERMET D'OBTENIR UN DISPOSITIF QUI ATTEINT L'OBJECTIF FIXE. LA FORMULATION DANS L'ESPACE DES COMMANDES, AIDE A DEFINIR UNE CONFIGURATION D'ACTIONNEURS AVEC UNE COMMANDE IDEALE QUI TIENT COMPTE DE LA CONNAISSANCE DU MODELE. IL EST DEMANDE ENSUITE A UN NOMBRE FINI DE SENSEURS D'ESTIMER CETTE COMMANDE. DEUX APPROCHES SONT DEVELOPPEES. LA PREMIERE RESIDE DANS LA DEFINITION D'UN FILTRAGE SUR DES CAPTEURS DE POSITION PREDETERMINEE ET LA SECONDE SUR L'OPTIMISATION DES POSITIONS DES SENSEURS. AVEC LA SECONDE METHODE, LES CAPTEURS SONT PLACES SUR LES NUDS DU CHAMP RESIDUEL IDEAL. CE RESULTAT EST ANALYSE LORSQUE LES NUDS SONT ABSENTS, PUIS VALIDE EXPERIMENTALEMENT. LA DEMARCHE PROPOSEE PRESENTE L'INCONVENIENT D'ETRE TRIBUTAIRE DU CHAMP PRIMAIRE. NOUS PROPOSONS ALORS UN MOYEN DE DISCRIMINER LES DISPOSITIFS DE CONTROLE RELATIVEMENT A LEUR ROBUSTESSE AUX VARIATIONS DU CHAMP PRIMAIRE. LA METHODE GLOBALE EST FINALEMENT INSEREE DANS UN MODELE NUMERIQUE DE LA CABINE D'UN AVION COUPLEE A SON FUSELAGE. LE NOMBRE IMPORTANT DE DEGRES DE LIBERTE DU MODELE ELEMENTS FINIS SUPPOSE UN TRAITEMENT DES OPERATIONS POUR REDUIRE LES TEMPS DE CALCUL. LES RESULTATS OBTENUS FOURNISSENT DES INFORMATIONS INTERESSANTES SUR LES MECANISMES DE CONTROLE D'UNE CAVITE VIBRANTE
Download or read book Colloque de Physique written by and published by . This book was released on 1990 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book First French Conference on Acoustics written by Paul Filippi and published by . This book was released on 1990 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book History of Nonlinear Oscillations Theory in France 1880 1940 written by Jean-Marc Ginoux and published by Springer. This book was released on 2017-04-18 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reveals the French scientific contribution to the mathematical theory of nonlinear oscillations and its development. The work offers a critical examination of sources with a focus on the twentieth century, especially the period between the wars. Readers will see that, contrary to what is often written, France's role has been significant. Important contributions were made through both the work of French scholars from within diverse disciplines (mathematicians, physicists, engineers), and through the geographical crossroads that France provided to scientific communication at the time. This study includes an examination of the period before the First World War which is vital to understanding the work of the later period. By examining literature sources such as periodicals on the topic of electricity from that era, the author has unearthed a very important text by Henri Poincaré, dating from 1908. In this work Poincaré applied the concept of limit cycle (which he had introduced in 1882 through his own works) to study the stability of the oscillations of a device for radio engineering. The “discovery” of this text means that the classical perspective of the historiography of this mathematical theory must be modified. Credit was hitherto attributed to the Russian mathematician Andronov, from correspondence dating to 1929. In the newly discovered Poincaré text there appears to be a strong interaction between science and technology or, more precisely, between mathematical analysis and radio engineering. This feature is one of the main components of the process of developing the theory of nonlinear oscillations. Indeed it is a feature of many of the texts referred to in these chapters, as they trace the significant developments to which France contributed. Scholars in the fields of the history of mathematics and the history of science, and anyone with an interest in the philosophical underpinnings of science will find this a particularly engaging account of scientific discovery and scholarly communication from an era full of exciting developments.
Download or read book The Telephone the Microphone and the Phonograph written by comte Th Du Moncel and published by . This book was released on 1879 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adhesion Between Polymers and Concrete Adh sion Entre Polym res Et B ton written by H. R. Sasse and published by Springer. This book was released on 1986 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt: Preface Adhesion is a phenomenon architects and civil engineers are not very familiar with. In other disciplines knowledge about surface properties and the background of bonding energies is also far from satisfactory; nevertheless there are many important· applications in concrete engineering, where adhesion is necessary for success and durability. These include: - coating and painting - repair of concrete surfaces - bonding of fresh to old concrete - crack injection - glueing of precast elements - glueing of steel to concrete, etc. In 1981 RILEM established the technical committee 52-RAC 'Resin Adherence to Concrete'. The main aims of the committee's work were - to collect research results and practical experiences - to initiate and coordinate research programs - to develop, on a scientific base, test methods for field and for laboratory purposes. One of the results of the committee's work is a state-of-the-art report, which will be presented orally as a General Report at the International Symposium ISAP '86, and will be printed either in the RILEM journal Materials and Structures or separately. Several test recommendations have been elaborated and will be prepared as drafts for the participants ofISAP '86. These are: - direct tensile test - pull-off test - direct shear test - slant shear test - four-point bending test - dynamic loading test - thermal compatibility test (two versions) - injectibility test.
Download or read book Audio Effectiveness in Aviation written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Aerospace Medical Panel. Symposium and published by . This book was released on 1997 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Philosophy in a Time of Terror written by Giovanna Borradori and published by University of Chicago Press. This book was released on 2013-05-28 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: The idea for Philosophy in a Time of Terror was born hours after the attacks on 9/11 and was realized just weeks later when Giovanna Borradori sat down with Jürgen Habermas and Jacques Derrida in New York City, in separate interviews, to evaluate the significance of the most destructive terrorist act ever perpetrated. This book marks an unprecedented encounter between two of the most influential thinkers of our age as here, for the first time, Habermas and Derrida overcome their mutual antagonism and agree to appear side by side. As the two philosophers disassemble and reassemble what we think we know about terrorism, they break from the familiar social and political rhetoric increasingly polarized between good and evil. In this process, we watch two of the greatest intellects of the century at work.
Download or read book Dictionary of Building and Civil Engineering written by Don Montague and published by Taylor & Francis. This book was released on 1996 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dual-language dictionary lists over 20,000 specialist terms in both French and English, covering architecture, building, engineering and property terms. It meets the needs of all building professionals working on projects overseas. It has been comprehensively researched and compiled to provide an invaluable reference source in an increasingly European marketplace.
Download or read book Government Reports Annual Index written by and published by . This book was released on 1988 with total page 1100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coasts Under Changing Climate Observations and Modeling written by Rafael Almar and published by Frontiers Media SA. This book was released on 2022-01-04 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NATO Glossary of Terms and Definitions written by North Atlantic Treaty Organization and published by CreateSpace. This book was released on 2013-03-08 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: NATO Glossary of terms and definitions (English and French). Listing terms of military significance and their definitions for use in NATO.
Download or read book Broken Music written by Ursula Block and published by . This book was released on 19?? with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Online Informal Learning of English written by G. Sockett and published by Springer. This book was released on 2014-09-26 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: Young people around the world are increasingly able to access English language media online for leisure purposes and interact with other users of English. This book examines the extent of these phenomena, their effect on language acquisition and their implications for the teaching of English in the 21st century.
Download or read book Whylah Falls written by George Elliott Clarke and published by . This book was released on 1999 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whylah Falls is a passionate play about poets and the lies they tell in the pursuit of love.
