• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 16
  • 15
  • 13
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 54
  • 10
  • 9
  • 8
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Techniques of cumulative quantitative characterization of the thorax using audiosonic methods /

Druzgalski, Christopher Krzysztof January 1978 (has links)
No description available.
22

A new stethoscope for reduction of heart sounds from lung sound recordings.

January 2001 (has links)
Yip Lung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Abstracts in English and Chinese. / Chapter 1 --- Introduction / Chapter 1.1 --- Heart and Lung Diseases --- p.1 / Chapter 1.1.1 --- Hong Kong --- p.1 / Chapter 1.1.2 --- China --- p.2 / Chapter 1.1.3 --- the United States of America (USA) --- p.3 / Chapter 1.2 --- Auscultation --- p.3 / Chapter 1.2.1 --- Introduction of Auscultation --- p.4 / Chapter 1.2.2 --- Comparison between Auscultation and Ultrasound --- p.6 / Chapter 1.3 --- Stethoscope --- p.7 / Chapter 1.3.1 --- History of Stethoscope --- p.7 / Chapter 1.3.2 --- New Electronic Stethoscope --- p.14 / Chapter 1.4 --- Main Purpose of the Study --- p.16 / Chapter 1.5 --- Organization of Thesis --- p.16 / References --- p.18 / Chapter 2 --- A New Electronic Stethoscope's Head / Chapter 2.1 --- Introduction --- p.20 / Chapter 2.2 --- Biopotential Electrode --- p.21 / Chapter 2.2.1 --- Flexible Electrode --- p.21 / Chapter 2.2.2 --- Laplacian Electrocardiogram --- p.22 / Chapter 2.3 --- Transducer --- p.25 / Chapter 2.4 --- Design of the Head of Stethoscope --- p.26 / Chapter 2.5 --- Experimental Results --- p.27 / Chapter 2.5.1 --- Bias Voltage of Condenser Microphone --- p.27 / Chapter 2.5.2 --- Frequency Response of New Stethoscope's Head --- p.29 / Chapter 2.6 --- Discussion --- p.30 / Chapter 2.7 --- Section Summary --- p.31 / References --- p.33 / Chapter 3 --- Signal Pre-processing Unit / Chapter 3.1 --- Introduction --- p.35 / Chapter 3.2 --- High Input Impedance IC Amplifier --- p.36 / Chapter 3.3 --- Voltage Control Voltage Source High Pass Filter Circuit --- p.37 / Chapter 3.4 --- Multiple Feed Back Low Pass Filter Circuit --- p.39 / Chapter 3.5 --- Overall Circuit --- p.41 / Chapter 3.6 --- Experimental Results --- p.43 / Chapter 3.7 --- Discussion --- p.46 / Chapter 3.8 --- Section Summary --- p.47 / References --- p.48 / Chapter 4 --- Central Platform / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.2 --- Adaptive Filter --- p.49 / Chapter 4.2.1 --- Introduction to Adaptive Filtering --- p.49 / Chapter 4.2.2 --- Least-Mean-Square (LMS) Algorithm --- p.51 / Chapter 4.2.3 --- Applications --- p.52 / Chapter 4.3 --- Offline Processing --- p.54 / Chapter 4.3.1 --- WINDAQ and MATLAB --- p.55 / Chapter 4.3.2 --- Direct Reference Algorithm --- p.57 / Chapter 4.3.3 --- Determination of Parameters in DRA --- p.62 / Chapter 4.3.4 --- Experimental Results of DRA --- p.67 / Chapter 4.3.5 --- Acoustic Waveform Based Algorithm --- p.72 / Chapter 4.3.6 --- Experimental Results of AWBA --- p.81 / Chapter 4.4 --- Online Processing --- p.85 / Chapter 4.4.1 --- LABVIEW --- p.85 / Chapter 4.4.2 --- Automated Gain Control --- p.88 / Chapter 4.4.3 --- Implementation of LMS adaptive filter --- p.89 / Chapter 4.4.4 --- Experimental Results of Online-AGC --- p.92 / Chapter 4.5 --- Discussion --- p.93 / Chapter 4.6 --- Section Summary --- p.97 / References --- p.98 / Chapter 5 --- Conclusion and Further Development / Chapter 5.1 --- Conclusion of the Main Contribution --- p.100 / Chapter 5.2 --- Future Works --- p.102 / Chapter 5.2.1 --- Modification of the Head of Stethoscope --- p.102 / Chapter 5.2.2 --- Validation of Abnormal Breath --- p.102 / Chapter 5.2.3 --- Low Frequency Analysis --- p.102 / Chapter 5.2.4 --- AGC-AWBA Approach --- p.102 / Chapter 5.2.5 --- Standalone Device --- p.103 / Chapter 5.2.6 --- Demand on Stethoscope --- p.109 / References --- p.110 / Appendix / Chapter A.1 --- Determination of parameters in VCVS High Pass Filter --- p.106 / Chapter A.2 --- Determination of parameters in MFB Low Pass Filter --- p.110 / Chapter A.3 --- Source code of DRA (MATLAB) --- p.114 / Chapter A.4 --- Source code of AWBA (MATLAB) --- p.129 / Chapter A.5 --- Source code of online AGC (LABVIEW) --- p.134
23

Métrologie par photogrammétrie aéroportée légère : application au suivi d'évolution de digues / Metrology with light aerial photogrammetry : application to dykes monitoring

Tournadre, Vincent 21 December 2015 (has links)
En embarquant un appareil photo grand public de bonne qualité sur un drone ou un ULM, il est aujourd'hui possible de réaliser de manière 100% automatique des modélisations 3D visuellement « parfaites » ou en tout cas suffisante tant que ce modèle est utilisé comme support de communication. Par contre, les performances de ces méthodes sont encore mal maîtrisées dans le contexte où l'on veut utiliser le modèle comme outil de mesure. Les géométries d'acquisition linéaires, propices aux dérives de bandes photogrammétriques, en sont un exemple représentatif. Un phénomène de courbure de bande est alors constaté, nécessitant un travail de mesure terrain conséquent pour être corrigé. Ces imprécisions limitent l'intérêt de telles acquisitions, et sont un défi pour la communauté des photogrammètres, le marché naissant du drone, mais aussi de multiples industriel ayant un intérêt fort pour des systèmes capables d'assurer un suivi de mouvement 3D des sols avec une précision de quelques millimètres (par exemple suivi de digues, érosion agraire, surveillance de réseaux ferrés,...). Cette thèse est un projet de recherche issu d'un partenariat entre l'Institut National de l'Information Géographique et Forestière (IGN), et la Compagnie Nationale du Rhône (CNR), concessionnaire chargé d'entretenir et surveiller le réseau de digues de retenue du fleuve. Il s'agit - à partir de moyens aériens légers - d'arriver à un système d'auscultation plus rapide, plus économique et offrant une géométrie plus fine que les systèmes topométriques utilisés actuellement. Nous présentons tout d'abord une étude comparative des moyens aériens légers, montrant l'intérêt et les limitations des drones face aux ULM. Nous proposons des procédures d'acquisition adaptées aux géométries étudiées, permettant de limiter de manière opérationnelle les dérives. Dans un second temps, nous montrons que les phénomènes de courbure sont liés à des modèles d'orientation internes inadaptés, et nous proposons une procédure d'auto-calibration en trois étapes. Nos essais menés sur des chantiers linéaires montrent que le calcul des orientations est sensiblement amélioré (d'écarts métriques à des écarts centimétriques). Dans un troisième temps, nous proposons une optimisation de la compensation sur les points d'appuis, permettant de diminuer le nombre de mesures nécessaires. Enfin, nous présentons des méthodes pour contrôler l'incertitude des modèles 3D générés, et à travers une analyse diachronique, des exemples de suivi d'évolution permettant de suivre finement l'évolution de tels ouvrages / By embarking a good quality consumer grade camera on an Unmanned Aerial Vehicle (UAV) or on an ultralight system, it is possible to create – fully automatically – 3D models that are visually ''perfect'', or at least sufficient for visual or communication purposes. However, the accuracy of these methods is still a concern, especially if the resulting models are to be used as measuring tools. Linear acquisitions – also known as corridor mapping – are a striking example of the uncontrolled error propagation. A bowl effect is often observed, requiring multiple ground measurements to be overcome. These effects restrict the interest of such acquisitions. They are a challenge for the photogrammetrists community, the emerging civil UAV market, as well as many industrials interested in systems able to monitor ground deformations with an accuracy within a few millimeters (railway network surveillance, erosion of agricultural land, embankments monitoring,…).This thesis is an applied research project, led with a river concessionary which has the responsibility to maintain and keep under surveillance its containment dykes network. The purpose is to use light aerial systems as a mean for a monitoring system which is faster, cheaper, and more detailed than the topometric solutions used so far. First of all, we present a comparative study to understand, between UAVs and ultralight system, which tool is the most adapted for a specific need. We propose refined acquisition procedures, than can be used to limit operationally the drifts. In a second phase, we identify the internal camera model as the weak link, and propose a three steps auto-calibration procedure. Our tests led on linear acquisitions demonstrate that the external orientations accuracy are noticeably improved (from decimetric or even metric disparities, reduced to a few centimeters or less). In a third part, we propose an optimization of the adjustment on the ground control points, which is a way to limit the amount of ground measurements necessary. Finally, we present methods to control 3D models uncertainty, and through a diachronic analysis, examples of how such data can be used to monitor such structures through time
24

L'utilisation de systèmes intelligents réseautés pour l'instrumentation des structures en génie civil

Chafei, Ayman January 2009 (has links)
Dans cette recherche, on a conçu et validé un nouveau noeud sans fil qui sera intégré dans un système automatique de contrôle des structures de génie civil. Le prototype est conçu à partir des dernières technologies dans le domaine des systèmes embarqués. Le prototype utilise la technologie développée pour les réseaux sans fil personnels WPAN (Wireless Personal Area Network) pour la transmission de données vers la centrale locale d'interrogation des données. Les capacités de calcul que le prototype possède nous permettent d'implémenter et d'exécuter plusieurs algorithmes de contrôle de l'état des structures. La transformée de Fourier rapide est utilisée comme algorithme illustratif dans le noeud sans fil. L'objectif de cette recherche est de mettre en place un réseau de capteurs sans fil qui supporte le calcul collaboratif en temps réel des dominées mesurées, pour l'identification des dommages potentiels dans la structure.
25

Development of a Software Application to Extract the Features of Normal Respiratory Sounds from the Lungs and the Trachea

Sabarinathan, Ranjani 01 January 2006 (has links)
Auscultation has been widely regarded as one of the most important noninvasive diagnostic tools for clinical diagnosis of the respiratory tract. The purpose of this thesis was to develop a software application capable of extracting the key features of respiratory sound signals from the lungs and trachea of healthy persons. The efficacy of the program was evaluated by the verification of the important features of the sound signals from the left and right lungs and the trachea such as 1) right and left lung symmetry and 2) dissimilarity between the trachea and both lungs. The program was developed in LabView and was designed to capture the respiratory sound signals from the lungs and the trachea in real-time and process them in the time and frequency domains for further analysis. The features compared were 1) signal amplitude in the time domain and 2) power spectra in the frequency domain. Results of the study had shown that the program had been able to verify that 1) the key features of the breath sound signals from the left and right lungs were similar and 2) the features of the signals from the trachea and both lungs were different.
26

Nouveaux outils de communication pour le diagnostic partagé et la surveillance du patient - application au domaine de l'auscultation

Reichert, Sandra 10 October 2009 (has links) (PDF)
Ce travail est fondé sur l'étude de nouveaux outils de télémédecine ; l'accent est mis sur la création d'un système d'auscultation. Trois points ont été développés : - la conception d'une plateforme innovante pour un meilleur suivit du patient et des échanges simplifiés entre professionnels de santé. Le système d'auscultation proposé permet notamment de réaliser des enregistrements et visualisations d'auscultations antérieures, des télé-auscultations, des envois de données auscultatoires à un expert, de demander un second avis temps réel, d'apporter une aide pédagogique pour l'enseignement de l'auscultation. - l'étude et la réalisation d'un prototype de stéthoscope électronique. En effet, nos travaux ont mis en lumière la nécessité de disposer d'un outil de capture du son performant et adapté à une analyse automatique. Cet outil doit disposer de caractéristiques particulières en termes de courbe de réponse, de bande de fréquence, de filtrage... mais également d'ergonomie. - l'étude d'un format d'échange des données auscultatoires. Aujourd'hui, il n'existe pas de standard pour transmettre de telles données. Nous avons mis en lumière l'intérêt de permettre cet échange d'informations, défini la nature des données devant être transportées (son mais également données patient, médico-légales, sémiologie...) et le moyen de les transmettre.
27

Auscultation non destructive des structures en béton atteintes par la réaction alcalis-granulats

Bui, Le Diem Quynh January 2012 (has links)
Un nombre important de structures à travers le monde sont touchées par la réaction alcalis-silice (RAS), mais plusieurs points restent à valider concernant leur diagnostic. Il y a donc un besoin d'un moyen efficace d'identifier le problème, quantifier l'endommagement et faire le suivi des structures dans le temps afin de déterminer notamment l'efficacité des mesures de mitigation. Le projet présenté dans ce mémoire met en relief les travaux de recherches menés dans le cadre d'un contrat de recherche avec le Federal Highway Administration des USA. L'objectif à moyen et long terme est d'élaborer un guide d'utilisation essais non destructifs sur les structures en service qui pourra être intégré à un protocole d'inspection. Ce projet a été scindé en deux parties complémentaires, soit une partie d'essais in situ et une partie en laboratoire où une nouvelle technique non linéaire du saut temporel a été étudiée. La maniabilité et la sensibilité d'une combinaison de techniques acoustiques pour l'auscultation in situ ont été mises à l'épreuve sur des structures en service. Des ponts et viaducs autoroutiers dans le nord-est des États-Unis ont été évalués en utilisant l'impact-écho, la vitesse d'impulsions ultrasonores et le saut temporel, une nouveauté dans le contrôle non destructif. De ces trois techniques, quatre indicateurs ont été étudiés : vitesse provenant de la fréquence de résonance, la vitesse directe, la fréquence centroïde et le saut temporel. Le saut temporel est une technique où des rafales ultrasonores de hautes fréquences balaient le matériau pendant qu'une onde élastique de basses fréquences perturbe le matériau et causant un délai dans la propagation des ultrasons. Contrairement aux autres techniques non linéaires très sensibles mais non applicables sur le terrain, le saut temporel semble pouvoir être utilisé efficacement sur les structures en service. La technique permet également d'évaluer des paramètres linéaires telle que la vitesse d'impulsions ultrasonores en plus du paramètre non linéaire. L'étude a porté sur l'applicabilité à différents niveaux d'endommagement afin d'identifier les avantages et les limites de la technique ainsi que pour optimiser son utilisation avec différentes configurations de transmission. Les configurations indirecte et semi-directe ont été évaluées sur des échantillons de mortiers à différents niveaux d'endommagement généré par les cycles de gel-dégel. Les résultats ont démontré que le saut temporel est plus sensible lorsqu'utilisé en configuration de transmission indirecte, mais également beaucoup plus sensible que les indicateurs linéaires à l'initiation de l'endommagement. Sa sensibilité et sa versatilité (différents indicateurs pour différents niveaux d'endommagement) sont d'un grand intérêt pour l'évaluation rapide des structures.
28

Segurança de barragens : análise da instrumentação da barragem de Itaúba / Safety of dams : Analysis of instrumentation of Itaúba dam

Smiderle, Camila de Souza Dahm January 2014 (has links)
Neste trabalho foi feita a análise das leituras da instrumentação da barragem de terra e enrocamento de Itaúba, localizada no centro do estado do Rio Grande do Sul, coletada ao longo de 35 anos. A auscultação por instrumentação atual inclui medidores de vazão, piezômetros, marcos de deslocamento superficial e medidor de recalque tipo KM, compondo um banco de dados de 10.000 dados de leitura. Foi observado que as vazões medidas através dos drenos de fundação da barragem reduziram pela metade desde o primeiro ano de operação da barragem até o final de 2013, embora os níveis piezométricos do sistema de drenagem à jusante não tenham sofrido alteração. As vazões dos filtros inclinado e vertical são afetadas pelas chuvas, mesmo assim foi possível concluir que as vazões reduziram 1/3 em comparação com a vazão logo após o segundo enchimento do reservatório. A vazão pela barragem e fundação era de 1.800 l/min no primeiro ano de operação decrescendo para 930 l/min (dez / 2013). Observou-se que até o fim do período construtivo já haviam ocorrido 101,75cm de recalque (92% de todo o recalque medido). Os recalques do núcleo estabilizaram entre o 5° e 10° ano de operação da barragem, isto é, desde 1988 a barragem não apresenta recalques significativos. O recalque total de Itaúba foi de 109,6cm que representa 1,2% da altura da seção onde o medidor de recalque está instalado. A análise permite concluir que a Barragem de Itaúba esta estabilizada quanto aos deslocamentos verticais e horizontais. Apesar de tratarse de dados de leituras coletados desde 1976, as informações apresentadas aqui são de relevante interesse e ainda não haviam sido publicadas. / In this work, the analysis of Itauba dam instrumentation is carried out. This earth and rock fill dam is located in the center of Rio Grande do Sul state and the readings cover its 35 years of operation. The currentinstrumentation includes flow meters, piezometers, surface displacement and settlements gauge type KM, composing a 10,000 reading database. It was observed that the flow rates measured through the dam foundation drains reduced to half since the first year of dam operation, although the piezometric levels of the downstream drainage system showed no significant change. Flow rates of inclined and vertical filters are affected by the rains, even so it was still possible to conclude that the flows reduced circa of 1/3 compared to the flow after the second filling of the reservoir. The flow through the dam and foundation which was 1,800 l / min in the first year of operation decreased to 930 l / min (Dec / 2013). It was observed that by the end of the construction period had occurred 101,75cm of settlement (92% of all the measured settlement). The settlement core stabilized between the 5 th and 10th year of dam operation, that is, since 1988 the dam does not present significant settlements. The total discharge of Itaúba was 109,6cm representing 1.2% of the section height where repression meter is installed. The analysis shows that the Itaúba dam has stabilized its vertical and horizontal displacements.
29

Segurança de barragens : análise da instrumentação da barragem de Itaúba / Safety of dams : Analysis of instrumentation of Itaúba dam

Smiderle, Camila de Souza Dahm January 2014 (has links)
Neste trabalho foi feita a análise das leituras da instrumentação da barragem de terra e enrocamento de Itaúba, localizada no centro do estado do Rio Grande do Sul, coletada ao longo de 35 anos. A auscultação por instrumentação atual inclui medidores de vazão, piezômetros, marcos de deslocamento superficial e medidor de recalque tipo KM, compondo um banco de dados de 10.000 dados de leitura. Foi observado que as vazões medidas através dos drenos de fundação da barragem reduziram pela metade desde o primeiro ano de operação da barragem até o final de 2013, embora os níveis piezométricos do sistema de drenagem à jusante não tenham sofrido alteração. As vazões dos filtros inclinado e vertical são afetadas pelas chuvas, mesmo assim foi possível concluir que as vazões reduziram 1/3 em comparação com a vazão logo após o segundo enchimento do reservatório. A vazão pela barragem e fundação era de 1.800 l/min no primeiro ano de operação decrescendo para 930 l/min (dez / 2013). Observou-se que até o fim do período construtivo já haviam ocorrido 101,75cm de recalque (92% de todo o recalque medido). Os recalques do núcleo estabilizaram entre o 5° e 10° ano de operação da barragem, isto é, desde 1988 a barragem não apresenta recalques significativos. O recalque total de Itaúba foi de 109,6cm que representa 1,2% da altura da seção onde o medidor de recalque está instalado. A análise permite concluir que a Barragem de Itaúba esta estabilizada quanto aos deslocamentos verticais e horizontais. Apesar de tratarse de dados de leituras coletados desde 1976, as informações apresentadas aqui são de relevante interesse e ainda não haviam sido publicadas. / In this work, the analysis of Itauba dam instrumentation is carried out. This earth and rock fill dam is located in the center of Rio Grande do Sul state and the readings cover its 35 years of operation. The currentinstrumentation includes flow meters, piezometers, surface displacement and settlements gauge type KM, composing a 10,000 reading database. It was observed that the flow rates measured through the dam foundation drains reduced to half since the first year of dam operation, although the piezometric levels of the downstream drainage system showed no significant change. Flow rates of inclined and vertical filters are affected by the rains, even so it was still possible to conclude that the flows reduced circa of 1/3 compared to the flow after the second filling of the reservoir. The flow through the dam and foundation which was 1,800 l / min in the first year of operation decreased to 930 l / min (Dec / 2013). It was observed that by the end of the construction period had occurred 101,75cm of settlement (92% of all the measured settlement). The settlement core stabilized between the 5 th and 10th year of dam operation, that is, since 1988 the dam does not present significant settlements. The total discharge of Itaúba was 109,6cm representing 1.2% of the section height where repression meter is installed. The analysis shows that the Itaúba dam has stabilized its vertical and horizontal displacements.
30

Segurança de barragens : análise da instrumentação da barragem de Itaúba / Safety of dams : Analysis of instrumentation of Itaúba dam

Smiderle, Camila de Souza Dahm January 2014 (has links)
Neste trabalho foi feita a análise das leituras da instrumentação da barragem de terra e enrocamento de Itaúba, localizada no centro do estado do Rio Grande do Sul, coletada ao longo de 35 anos. A auscultação por instrumentação atual inclui medidores de vazão, piezômetros, marcos de deslocamento superficial e medidor de recalque tipo KM, compondo um banco de dados de 10.000 dados de leitura. Foi observado que as vazões medidas através dos drenos de fundação da barragem reduziram pela metade desde o primeiro ano de operação da barragem até o final de 2013, embora os níveis piezométricos do sistema de drenagem à jusante não tenham sofrido alteração. As vazões dos filtros inclinado e vertical são afetadas pelas chuvas, mesmo assim foi possível concluir que as vazões reduziram 1/3 em comparação com a vazão logo após o segundo enchimento do reservatório. A vazão pela barragem e fundação era de 1.800 l/min no primeiro ano de operação decrescendo para 930 l/min (dez / 2013). Observou-se que até o fim do período construtivo já haviam ocorrido 101,75cm de recalque (92% de todo o recalque medido). Os recalques do núcleo estabilizaram entre o 5° e 10° ano de operação da barragem, isto é, desde 1988 a barragem não apresenta recalques significativos. O recalque total de Itaúba foi de 109,6cm que representa 1,2% da altura da seção onde o medidor de recalque está instalado. A análise permite concluir que a Barragem de Itaúba esta estabilizada quanto aos deslocamentos verticais e horizontais. Apesar de tratarse de dados de leituras coletados desde 1976, as informações apresentadas aqui são de relevante interesse e ainda não haviam sido publicadas. / In this work, the analysis of Itauba dam instrumentation is carried out. This earth and rock fill dam is located in the center of Rio Grande do Sul state and the readings cover its 35 years of operation. The currentinstrumentation includes flow meters, piezometers, surface displacement and settlements gauge type KM, composing a 10,000 reading database. It was observed that the flow rates measured through the dam foundation drains reduced to half since the first year of dam operation, although the piezometric levels of the downstream drainage system showed no significant change. Flow rates of inclined and vertical filters are affected by the rains, even so it was still possible to conclude that the flows reduced circa of 1/3 compared to the flow after the second filling of the reservoir. The flow through the dam and foundation which was 1,800 l / min in the first year of operation decreased to 930 l / min (Dec / 2013). It was observed that by the end of the construction period had occurred 101,75cm of settlement (92% of all the measured settlement). The settlement core stabilized between the 5 th and 10th year of dam operation, that is, since 1988 the dam does not present significant settlements. The total discharge of Itaúba was 109,6cm representing 1.2% of the section height where repression meter is installed. The analysis shows that the Itaúba dam has stabilized its vertical and horizontal displacements.

Page generated in 0.0744 seconds