Дисертації з теми "3D displacement"

Avec le développement actuel des nano-technologies, la demande en matière d'étude du comportement des matériaux à des échelles micro ou nanoscopique ne cesse d'augmenter. Pour la mesure de forme ou de déformations tridimensionnelles à ces échelles de grandeur, l'acquisition d'images à partir d'un Microscope électronique à Balayage (MEB) couplée à l'analyse par corrélation d'images numériques s'est avérée une technique intéressante. Cependant, un MEB est un outil conçu essentiellement pour de la visualisation et son utilisation pour des mesures tridimensionnelles précises pose un certain nombre de difficultés comme par exemple le calibrage du système et la correction des fortes distorsions (spatiales et temporelles) présentes dans les images. De plus, le MEB ne possède qu'un seul capteur et les informations tridimensionnelles souhaitées ne peuvent pas être obtenues par une approche classique de type stéréovision. Cependant, l'échantillon à analyser étant monté sur un support orientable, des images peuvent être acquises sous différents points de vue, ce qui permet une reconstruction tridimensionnelle en utilisant le principe de vidéogrammétrie pour retrouver à partir des seules images les mouvements inconnus du porte-échantillon. La thèse met l'accent sur la nouvelle technique de calibrage et de correction des distorsions développée car c'est une contribution majeure pour la précision de la mesure de forme et de déformations 3D aux échelles de grandeur étudiées. Elle prouve que, contrairement aux travaux précédents, la prise en compte de la dérive temporelle et des distorsions spatiales d'images est indispensable pour obtenir une précision de mesure suffisante. Les principes permettant la mesure de forme par vidéogrammétrie et le calcul de déformations 2D et 3D sont aussi présentés en détails. Enfin, et dans le but de valider nos travaux et démontrer en particulier la précision de mesure obtenue, des résultats expérimentaux issus de différentes applications sont présentés
With the current development of nano-technology, there exists an increasing demand for three-dimensional shape and deformation measurements at this reduced-length scale in the field of materials research. Images acquired by Scanning Electron Microscope (SEM) systems coupled with analysis by Digital Image Correlation (DIC) is an interesting combination for development of a high magnification measurement system. However, a SEM is designed for visualization, not for metrological studies, and the application of DIC to the micro- or nano-scale with such a system faces the challenges of calibrating the imaging system and correcting the spatially-varying and time-varying distortions in order to obtain accurate measurements. Moreover, the SEM provides only a single sensor and recovering 3D information is not possible with the classical stereo-vision approach. But the specimen being mounted on the mobile SEM stage, images can be acquired from multiple viewpoints and 3D reconstruction is possible using the principle of videogrammetry for recovering the unknown rigid-body motions undergone by the specimen. The dissertation emphasizes the new calibration methodology that has been developed because it is a major contribution for the accuracy of 3D shape and deformation measurements at reduced-length scale. It proves that, unlike previous works, image drift and distortion must be taken into account if accurate measurements are to be made with such a system. Necessary background and required theoretical knowledge for the 3D shape measurement using videogrammetry and for in-plane and out-of-plane deformation measurement are presented in details as well. In order to validate our work and demonstrate in particular the obtained measurement accuracy, experimental results resulting from different applications are presented throughout the different chapters. At last, a software gathering different computer vision applications has been developed

Avec le développement actuel des nano-technologies, la demande en matière d'étude du comportement des matériaux à des échelles micro ou nanoscopique ne cesse d'augmenter. Pour la mesure de forme ou de déformation tridimensionnelles à ces échelles de grandeur, l'acquisition d'images à partir d'un Microscope Électronique à Balayage (MEB) couplée à l'analyse par corrélation d'images numériques s'est avérée une technique intéressante. Cependant, un MEB est un outil conçu essentiellement pour de la visualisation et son utilisation pour des mesures tridimensionnelles précises pose un certain nombre de difficultés comme par exemple le calibrage du système et la correction des fortes distorsions (spatiales et temporelles) présentes dans les images. De plus, le MEB ne possède qu'un seul capteur et les informations tridimensionnelles souhaitées ne peuvent pas être obtenues par une approche classique de type stéréovision. Cependant, l'échantillon à analyser étant monté sur un support orientable, des images peuvent être acquises sous différents points de vue, ce qui permet une reconstruction tridimensionnelle en utilisant le principe de vidéogrammétrie pour retrouver à partir des seules images les mouvements inconnus du porte-échantillon.

La thèse met l'accent sur la nouvelle technique de calibrage et de correction des distorsions développée car c'est une contribution majeure pour la précision de la mesure de forme et de déformations 3D aux échelles de grandeur étudiées. Elle prouve que, contrairement aux travaux précédents, la prise en compte de la dérive temporelle et des distorsions spatiales d'images est indispensable pour obtenir une précision de mesure suffisante. Les principes permettant la mesure de forme par vidéogrammétrie et le calcul de déformations 2D et 3D sont aussi présentés en détails. Dans le but de valider nos travaux et démontrer en particulier la précision de mesure obtenue, des résultats expérimentaux issus de différentes applications sont présentés tout au long de la thèse. Enfin, un logiciel rassemblant différentes applications de vision par ordinateur a été developpé.

This thesis proposes a novel computer vision-based target-free full-field 3D displacement measurement for civil engineering. Two cameras are combined as a binocular camera system to acquire the vibration video of civil structures. Some state-of-the-art methods including deep learning in the computer vision area are applied to realize target-free, full-field and tiny displacement measurements. A series of experimental tests and an in-field vibration test are conducted to validate the proposed vision measurement system.

This paper explores different bump mapping techniques and their implementation. Bump mapping is a technique that is used in computer games to make simple 3D objects look more detailed than what they really are. The technique involves using a texture to change the objects normals to simulate bumps and is used to avoid rendering high polygonal objects. Over the years some different techniques have been developed based on bump mapping, these are normal mapping, relief mapping, parallax occlusion mapping, quadtree displacement mapping and so on. The first part of this paper we go through our goals and our research methodology. We then write about four different techniques and describe how they work. We also go through how they are implemented. After that we start our experiments and measure the different techniques against each other. When the first testing has been done, we start to optimize the techniques and run a second test to see how much faster, if it is faster, the optimization is compared to the previous tests. When the tests are done, we present our test data and analyse them. Finally we discuss the techniques and the testing. Then we finish up with a conclusion.
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The purpose of this thesis is to investigate performance aspects of layered displacement blending; a technique used to render realistic and transformable objects in real time rendering systems using the GPU. Layered displacement blending is done by blending layers of color maps and displacement maps together based on values stored in an influence map. In this thesis we construct a theoretical and practical model for layered displacement blending. The model is implemented in a test bed application to enable measuring of performance aspects. The implementation is fed input with variations in triangle count, number of subdivisions, texture size and number of layers. The execution time for these different combinations are recorded and analyzed. The recorded execution times reveal that the amount of layers associated with an object has no impact on performance. Further analysis reveals that layered displacement blending is heavily dependent on the triangle count in the input mesh. The results show that layered displacement blending is a viable option to representing transformable objects in real time applications with respect to performance. This thesis provides; a theoretical model for layered displacement blending, an implementation of the model using the GPU and measurements of that implementation.

Abstract This thesis describes position-sensitive devices (PSDs) and optical sensor systems suitable for industrial tracking and displacement sensing applications. The main application areas of the proposed sensors include automatic pointing of a rangefinder beam and measuring the lateral displacement of an object. A conventional tracking sensor is composed of a laser illuminator, a misfocused quadrant detector (QD) receiver and a corner cube retroreflector (CCR) attached to the target. The angular displacement of a target from the receiver optical axis is detected by illuminating the target and determining the direction of the reflection using the QD receiver. The main contribution of the thesis is related to the modifications proposed for this conventional construction in order to make its performance sufficient for industrial applications that require a few millimetre to submillimetre accuracy. The work includes sensor optical construction modifications and the designing of new types of PSDs. The conventional QD-based sensor, although electrically very sensitive, is not considered optimal for industrial applications since its precision is severely hampered by atmospheric turbulence due to the misfocusing needed for its operation. Replacing the CCR with a sheet reflector is found to improve the precision of the conventional sensor construction in outdoor beam pointing applications, and is estimated to allow subcentimetre precision over distances of up to 100 m under most operating conditions. Submillimetre accuracy is achievable in close-range beam pointing applications using a small piece of sheet reflector, coaxial illumination and a focused QD receiver. Polarisation filtering is found to be effective in eliminating the main error contributor in close-range applications, which is low reflector background contrast, especially in cases when a sheet reflector has a specularly reflecting background. The tracking sensor construction is also proposed for measuring the aiming trajectory of a firearm in an outdoor environment. This time an order of magnitude improvement in precision is achieved by replacing the QD with a focused lateral effect photodiode (LEP). Use of this construction in cases of intermediate atmospheric turbulence allows a precision better than 1 cm to be achieved up to a distance of 300 m. A method based on averaging the positions of multiple reflectors is also proposed in order to improve the precision in turbulence-limited cases. Finally, various types of custom-designed PSDs utilising a photodetector array structure are presented for long-range displacement sensing applications. The goal was to be able to replace the noisy LEP with a low-noise PSD without compromising the low turbulence sensitivity achievable with the LEP. An order of magnitude improvement in incremental sensitivity is achievable with the proposed array PSDs.

In this study finite element modeling of three dimensional elliptic and semielliptic cracks in a hollow cylinder is considered. Three dimensional crack and cylinder are modeled by using finite element analysis program ANSYS. The main objectives of this study are as follows. First, Ansys Parametric Design Language (APDL) codes are developed to facilitate modeling of different types of cracks in cylinders. Second, by using these codes the effect of some parameters of the problem like crack location, cylinder&rsquo
s radius to thickness ratio (R/t), the crack geometry ratio (a/c) and crack minor axis to cylinder thickness ratio (a/t) on stress intensity factors for surface and internal cracks are examined. Mechanical and thermal loading cases are considered. Displacement Correlation Technique (DCT) is used to obtain Stress Intensity Factors.

The present thesis is part of the wide work required by the SEBESMOVA3D (SEeismic BEhavior of Scaled MOdels of groin VAults made by 3D printers) project whose first motivation is the preservation of the cultural heritage in case of seismic events. Therefore, the main topic of the thesis is the analysis of the seismic response of scaled models of groin vaults, made of plastic 3D printed bricks filled with mortar, and subjected to shaking table tests performed at the EQUALS laboratory of the University of Bristol. The work has been developed on two parallel binaries: the processing of the displacement data acquired in situ and the calibration of a FEM model.

Роботу виконано на кафедрі конструювання верстатів, інструментів та машин Тернопільського національного технічного університету імені Івана Пулюя Міністерства освіти і науки УкраїниЗахист відбудеться 27 травня 2019 р. о 12.00 годині на засіданні екзаменаційної комісії №11 у Тернопільському національному технічному університеті імені Івана Пулюя за адресою: 46001, м. Тернопіль, вул. Руська, 56, навчальний корпус №4, ауд. 4-101.
У дипломній роботі розглянуті питання, які пов'язані з аналізом жорсткості несучої системи верстата, процесу механічної обробки деталі, дослідженням формоутворення та розробкою оптимальної конструкції несучої системи верстата за допомогою програмного забезпечення Autodesk Inventor, зокрема модуля генеративного дизайну. Виконано 3D моделювання корпусу (станини) фрезерного верстата. Виконано статичний та модальний аналіз корпусу верстата.
The thesis deals with issues related to the analysis of the rigidity of the framework system, the machining process of the part, the study of forming and the development of the optimal design of the framework system of the machine using the software Autodesk Inventor, in particular the module of generative design. The 3D modeling of the body (frame) of the milling machine is executed. Had performed a static and modal analysis of the machine's framework.
Вступ; Перший розділ «Аналітичний розділ»; Другий розділ «Оптимізація схем формоутворення на проектованому верстаті і оптимізація його компонувальної схеми»; Третій розділ «Вибір та обґрунтування вихідних даних на розробку верстатного обладнання. технологічний розрахунок»; Четвертий розділ «Проектування конструкції верстатного обладнання»; П'ятий розділ «Науково-дослідний розділ»; Шостий розділ «Спеціальний розділ (комп'ютерні розрахунки та автоматизоване проектування)»; Сьомий розділ «Обґрунтування економічної ефективності»; Восьмий розділ «Охорона праці та безпека в надзвичайних ситуаціях»; Дев’ятий розділ «Екологія»; Висновки

A single 3D virtual system in orthodontic-surgical and restorative patients has not been developed. The study aims were to evaluate: (1) the performance of a Cartesian coordinate system (CSYS) to measure translational and rotational tooth displacement, and (2) maxillary and mandibular tooth, occlusion and bone displacement with the CSYS and a lingual landmarks mathematical registration method. Eleven maxillary and mandibular dental models following an orthodontic surgical and restorative treatment sequence case were retrospectively collected. These were laser scanned and processed using reverse engineering computer aided design (CAD) technology to generate 3D models from which 6 paired models were evaluated. Phase one measured the errors in: (1) the correlation between CSYS – ABC landmarks (3 landmarks positioned on the anterior palate) selection and resulting tooth measurements, and (2) operator tooth landmark placement. Phase two: (1) used the maxillary and mandibular teeth landmarks to calculate the orthodontic, restorative and orthognathic translations and rotational displacement, (2) used additional registered landmarks on the lingual tori and mandibular teeth (when considered immobile) to isolate mandibular tooth displacement, and (3) calculated the inter-arch measurements. Relevant results indicated: (1) CSYS – ABC allocation mean translational deviation errors were small with 3D distance > anteroposterior > horizontal =vertical axes. Incisors were the least affected teeth, while molars the most affected. (2) Operator Landmarks selection error was negligible. (3) No statistical difference in tooth movement analysis for the mandible de-rotation methods was observed at the pre-surgical restorative stage. Customised CSYS and lingual landmarks of mandibular tori registration permits clinical orthodontic, restorative and orthognathic displacement measurement.

Au cours du développement du cancer, la migration des cellules cancéreuse en 3D joue un rôle essentiel dans le processus de dissémination des métastases. L’étude de la migration cellulaire dans des matrices 3D ainsi que les conséquences induites sur cette matrice sont actuellement étudiées par plusieurs équipes de recherche. Notamment, la réorganisation de la matrice extracellulaire et plus précisément les déplacements des fibres de la matrice induits par les forces que la cellule exerce sont des études en plein essor. Nous avons étudié comment les cellules cancéreuses migrent dans des gels 3D en utilisant du collagène et de la fibronectine pour mimer la matrice extracellulaire des tissus. Nous avons utilisé un microscope confocal afin de visualiser le cytosquelette d’actine des cellules en fluorescence et les fibres de collagène en réflexion. Dans ce travail,nous avons utilisé différentes concentrations de collagène et des lignées cellulaires d’invasivités différentes. A partir des films 3D obtenus en microscopie, nous avons déterminé la vitesse et la persistance des cellules cancéreuses en fonction de leur invasivité et de la concentration de collagène. La vitesse augmente avec l’invasivité cellulaire et diminue avec l’augmentation de la concentration en collagène. La persistance ne dépend que de la concentration en collagène et décroit avec celle-ci. Nous avons également calculé les champs de déplacement des fibres de collagène à l’aide d’un programme de corrélation de volume. Nous avons pu étudier ces champs de déplacement en fonction du type de migration de la cellule, de l’invasivité cellulaire et de la concentration en collagène des gels. Nous avons montré que les normes de vecteurs de déplacement augmentent avec l’invasivité cellulaire et diminuent avec l’augmentation de concentration en collagène. Enfin, ces champs de déplacement nous ont permis de déterminer les étapes des migrations mésenchymateuse et amiboïde en 3D. Nous avons découvert 5 étapes pour la migration mésenchymateuse correspondant au repos de la cellule, à la création d’une extension membranaire, à l’adhésion de la cellule aux fibres, au détachement de l’arrière du corps cellulaire afin de permettre à la cellule de migrer et à la dissolution de l’adhésion cellule/fibre. 4 étapes ont été déterminées pour la migration amiboïde et correspondent au repos de la cellule, à la création d’une extension membranaire, au déplacement de la cellule en poussant sur son environnement et à la rotation de la cellule. Ces étapes associées à des champs de déplacement sont en accord avec la littérature et nous avons pu mettre en évidence de nouvelles étapes comme la rotation de la cellule dans la migration amiboïde.Ces résultats permettent de mieux comprendre comment se déroule la migration des cellules cancéreuses dans une matrice extracellulaire
3D migration of cancer cells plays an essential role in the dissemination of cells during metastasisin cancer. The behavior of cancer cells migrating in a 3D extracellular matrix and its consequences on themicroenvironment are still currently under investigation. The study of the reorganization of the extracellular matrixfibers and more precisely how the fibers move due to the forces that the cell exerts just start to be investigating.We studied how cancer cells migrate in 3D gels using collagen and fibronectin to mimic the extracellularmatrix. We used confocal microscopy to image the actin cytoskeleton of cells in fluorescence and fibers in reflectionover time. In our studies, we used different collagen concentrations and cell lines with different invasivities. Fromthese 3D movies, we determined cancer cell velocities and persistence as a function of collagen gel concentration aswell as cell invasiveness. The cells velocities increase with invasiveness and decrease with collagen concentration.As for persistence, it decreases with collagen concentration but it do not change with cells invasiveness. We alsocalculated the displacement field of the collagen using a volume correlation program. Using this information, westudied the fibers displacement induced by the cell depending on its migration type, its invasivity and the collagenconcentration. We showed norms of fibers deplacement vectors increase with cell invasiveness and decrease withcollagen concentration. Finally, the displacement fields enabled us to determine the migration steps of mesenchymaland amiboid migrations. We discovered 5 steps in mesenchymal migration : cell rest, creation of extension, adhesionof the cell to the fibers, detachment of the cell rear and dissolution of cell/fibers adhesions. 4 steps have beencharacterized in amiboid migration : cell rest, creation of extension, displacement of the cell by pushing on fibersand rotation of the cell. These steps associated with displacement fields are in agreement with litterature and wehighlighted new steps as the rotation of the cell in amiboid migration.Taken together these results enable us to better understand how the migration of cancer cells takes place in a3D matrix

L’objet de cette thèse est de développer des méthodologies permettant d’identifier la distribution spatiale des valeurs de perméabilité dans des échantillons de roches. Nous avons tout d’abord développé en laboratoire des expériences d’injection de fluide miscible très visqueux dans des échantillons initialement saturés par une saumure peu visqueuse. Pendant l’injection, l’évolution au cours du temps de la pression différentielle entre les deux faces de l’échantillon a été enregistrée par des capteurs de pression. En outre, des mesures scanner ont fourni une carte 3D de la porosité ainsi que des cartes 3D décrivant la distribution spatiale des concentrations dans l’échantillon à différents temps. Nous avons mis en place une méthode d’interprétation donnant directement le profil 1D de la perméabilité le long de la direction d’écoulement à partir de la pression différentielle mesurée au cours du temps. Cette méthode a été validée numériquement et expérimentalement. Puis, afin d’affiner la description de l’agencement des valeurs de perméabilité dans l’échantillon, c’est à dire d’obtenir un modèle 3D de perméabilité représentatif de l’échantillon, nous avons développé une méthodologie itérative de calage des pressions et des concentrations. Cette méthode passe par deux étapes : une optimisation simple pour capturer l’hétérogénéité dans la direction de l’écoulement et une optimisation complexe pour capturer l’hétérogénéité transverse. Cette méthode a été validée à partir de tests numériques. La méthode a été appliquée à deux des expériences d’injection de fluide visqueux. Nous avons pu alors déterminer des modèles de perméabilité capables de reproduire assez bien les données de pression et de concentration acquises pendant l’injection
The objective of this study is to develop new methodologies to identify the spatial distribution of permeability values inside the heterogeneous core samples. We developed laboratory viscous miscible displacements by injecting high viscosity glycerin into the core samples initially saturated by low viscosity brine. The pressure drop across the samples was measured as a function of time until breakthrough. Meanwhile, CT scan measurements provided a 3D porosity map plus several 3D maps of concentration distribution inside the core samples at different times. A simple permeability mapping technique was developed deducing a one-dimensional permeability profile along the flow direction from the measured pressure drop data. The method was validated with both numerical and laboratory experiments. To go beyond one-dimensional characterization of permeability into cores, we developed an iterative process for matching pressure and concentration data. This method consisted of two steps: a simple optimization for capturing the permeability heterogeneity along the flow direction axis and a complex optimization for capturing transversal permeability heterogeneities. The methodology was validated by numerical data. It was also applied to the data collected from two laboratory viscous miscible displacements. We showed that the final 3D permeability models reproduce well the measured pressure drop and concentration data

Mestrado em Engenharia Mecânica
Vision systems have already proven to be a useful tool in various elds. The ease of their implementation, allied to their low cost mean that their growth potential is immense. In this dissertation it is proposed a approach to measure strains in metallic surfaces, using stereo vision. This approach is based on the 3D DIC. This method measures the strain of the surface by dividing this surface in small sections, called subsets, and iteratively nding the equation that describes its shape variation through time. However, calculating the transformation of this subset is very timeconsuming. The proposed approach tries to optimize this calculation by rst determine the displacement eld, and then the strain eld by derivation. The dissertation also presents some experimental data and practical considerations relatively to the camera setup and image equalization algorithms in order to obtain better disparity maps. The results were veri ed experimentally and compared with the results obtained from other softwares.
Os sistemas de vis~ao j a provaram ser uma ferramenta util em v arios campos. A facilidade da sua implementa c~ao, aliada ao seu baixo custo signi cam que o seu potencial de crescimento e enorme. Nesta disserta c~ao e proposta uma abordagem para medir deforma c~oes em superf cies met alicas usando vis~ao stereo. Esta abordagem e baseada na t ecnica 3D DIC. Este m etodo mede as deforma c~oes da superf cie dividindo-a em pequenas se c~oes, designadas por sub- sets, tentando iterativamente encontrar a equa c~ao que de ne as varia c~oes das suas formas ao longo do tempo. No entanto, o c alculo das transforma c~oes destes subsets e demorado. A abordagem proposta pretende pretende otimizar este c alculo determinando primeiro o campo de deslocamentos e depois o campo das deforma c~oes atrav es da deriva c~ao. A disserta c~ao apresenta tamb em dados experimentais e considera c~oes pr aticas relativamente a con gura c~ao (setup) das c^amaras e algoritmos de equaliza c~ao de imagens de forma a se obterem melhores mapas de disparidade. Os resultados foram veri cados experimentalmente e comparados com os resultados obtidos por outros softwares.

L’observation de la Terre par des systèmes d’acquisition d’images permet de suivre l’évolution temporelle de phénomènes naturels tels que les séismes, les volcans ou les mouvements gravitaires. Différentes techniques existent dont l’imagerie satellitaire, la photogrammétrie terrestre et les mesures in-situ. Les séries temporelles d’images issues d’appareils photo automatiques (Time Lapse) sont une source d’informations en plein essor car elles offrent un compromis intéressant en termes de couverture spatiale et de fréquence d’observation pour mesurer les déplacements de surface de zones spécifiques. Cette thèse est consacrée à l’analyse de séries d’images issues de la photographie terrestre et de l’imagerie radar satellitaire pour la mesure du déplacement des glaciers Alpins. Nous nous intéressons en particulier aux problèmes du traitement de Time Lapse stéréo pour le suivi d’objets géophysiques dans des conditions terrain peu favorables à la photogrammétrie. Nous proposons une chaîne de traitement mono-caméra qui comprend les étapes de sélection automatique des images, de recalage et de calcul de champs de déplacement bidimensionnel (2D). L’information apportée par les couples stéréo est ensuite exploitée à l’aide du logiciel MICMAC pour reconstruire le relief et obtenir le déplacement tridimensionnel(3D). Plusieurs couples d’images radar à synthèse d’ouverture (SAR) ont également été traités à l’aide des outils EFIDIR pour obtenir des champs de déplacement 2D dans la géométrie radar sur des orbites ascendantes ou descendantes. La combinaison de mesures obtenues quasi-simultanément sur ces deux types d’orbites permet de reconstruire le déplacement 3D. Ces méthodes ont été mises en oeuvre sur des séries de couples stéréo acquis par deux appareils photo automatiques installés sur la rive droite du glacier d’Argentière et sur des images du satellite TerraSAR-X couvrant le massif du Mont-Blanc. Les résultats sont présentés sur des données acquises lors d’une expérimentation multi-instruments menée en collaboration avec l’IGN à l’automne 2013, incluant le déploiement d’un réseau de Géocubes qui ont fournit des mesures GPS. Elles sont utilisées pour évaluer la précision des résultats obtenus par télédétection proximale et spatiale sur ce type de glacier
Earth observation by image acquisition systems allows the survey of temporal evolution of natural phenomena such as earthquakes, volcanoes or gravitational movements. Various techniques exist including satellite imagery, terrestrial photogrammetry and in-situ measurements. Image time series from automatic cameras (Time Lapse) are a growing source of information since they offer an interesting compromise in terms of spatial coverage and observation frequency in order to measure surface motion in specific areas. This PhD thesis is devoted to the analysis of image time series from terrestrial photography and satellite radar imagery to measure the displacement of Alpine glaciers. We are particularly interested in Time Lapse stereo processing problems for monitoring geophysical objects in unfavorable conditions for photogrammetry. We propose a single-camera processing chain that includes the steps of automatic photograph selection, coregistration and calculation of two-dimensional (2D) displacement field. The information provided by the stereo pairs is then processed using the MICMAC software to reconstruct the relief and get the three-dimensional (3D) displacement. Several pairs of synthetic aperture radar (SAR) images were also processed with the EFIDIR tools to obtain 2D displacement fields in the radar geometry in ascending or descending orbits. The combination of measurements obtained almost simultaneously on these two types of orbits allows the reconstruction of the 3D displacement. These methods have been implemented on time series of stereo pairs acquired by two automatic cameras installed on the right bank of the Argentière glacier and on TerraSAR-X satellite images covering the Mont-Blanc massif. The results are presented on data acquired during a multi-instrument experiment conducted in collaboration with the French Geographic National Institute (IGN) during the fall of 2013,with a network of Géocubes which provided GPS measurements. They are used to evaluate the accuracy of the results obtained by proximal and remote sensing on this type of glacier

A multiple-sensor optical shape measurement system (SMS) based on the principle of white-light fringe projection has been developed and commercialised by Loughborough University and Phase Vision Ltd for over 10 years. The use of the temporal phase unwrapping technique allows precise and dense shape measurements of complex surfaces; and the photogrammetry-based calibration technique offers the ability to calibrate multiple sensors simultaneously in order to achieve 360° measurement coverage. Nevertheless, to enhance the applicability of the SMS in industrial environments, further developments are needed (i) to improve the calibration speed for quicker deployment, (ii) to broaden the application range from shape measurement to deformation field measurement, and (iii) to tackle practically-challenging surfaces of which specular components may disrupt the acquired data and result in spurious measurements. The calibration process typically requires manual positioning of an artefact (i.e., reference object) at many locations within the view of the sensors. This is not only timeconsuming but also complicated for an operator with average knowledge of metrology. This thesis introduces an automated artefact positioning system which enables automatic and optimised distribution of the artefacts, automatic prediction of their whereabouts to increase the artefact detection speed and robustness, and thereby greater overall calibration performance. This thesis also describes a novel technique that integrates the digital image correlation (DIC) technique into the present fringe projection SMS for the purpose of simultaneous shape and deformation field measurement. This combined technique offers three key advantages: (a) the ability to deal with geometrical discontinuities which are commonly present on mechanical surfaces and currently challenging to most deformation measurement methods, (b) the ability to measure 3D displacement fields with a basic single-camera single-projector SMS with no additional hardware components, and (c) the simple implementation on a multiple-sensor hardware platform to achieve complete coverage of large-scale and complex samples, with the resulting displacement fields automatically lying in a single global coordinate system. A displacement measurement accuracy of ≃ 1/12,000 of the measurement volume, which is comparable to that of an industry-standard DIC system, has been achieved. The applications of this novel technique to several structural tests of aircraft wing panels on-site at the research centre of Airbus UK in Filton are also presented. Mechanical components with shiny surface finish and complex geometry may introduce another challenge to present fringe projection techniques. In certain circumstances, multiple reflections of the projected fringes on an object surface may cause ambiguity in the phase estimation process and result in incorrect coordinate measurements. This thesis presents a new technique which adopts a Fourier domain ranging (FDR) method to correctly identifying multiple phase signals and enables unambiguous triangulation for a measured coordinate. Experiments of the new FDR technique on various types of surfaces have shown promising results as compared to the traditional phase unwrapping techniques.

Ce travail de thèse décrit l'application de méthodes d'analyse innovantes à la caractérisation des propriétésmécaniques et électriques de matériaux composites.Le Chapitre premier dresse un état de l'art des fondamentaux théoriques et pré requis nécessaires à lacompréhension du manuscrit. Un regard critique permet de dégager une stratégie pour l'analyse, basée d'une partsur des méthodes holographiques numériques et d'autre part sur des techniques de mesure diélectrique.Le Chapitre second est dédié au choix de la méthode d'holographie numérique. En particulier, la configurationimage montre quelques particularités qui sont analysées en détail : le rôle du diaphragme d'ouverture du systèmed'imagerie. Nous concluons que la méthode d'holographie de Fresnel présente des avantages d'achromatismepour les applications avec plusieurs longueurs d'onde.Le 3ème Chapitre présente deux applications de l'holographie numérique au contrôle de structures compositesincorporées avec des pastilles piézoélectriques dédiées à l'émission acoustique. Nous avons démontré en premiertemps, la possibilité d'analyser par holographie numérique de Fresnel en temps moyenné le comportementvibratoire des poutres composites excitées harmoniquement. Dans un second temps, on a montré que les pastillesutilisées influencent le comportement mécanique des matériaux en régime statique.Le Chapitre 4 présente l'analyse expérimentale et numérique des structures composites soumises à un essai decisaillement en flexion trois points rapprochés. Nous présentons les résultats obtenus pour des applications à deséchantillons lin/époxy et lin/carbone/époxy.Le 5ème Chapitre aborde l'analyse des propriétés diélectriques des composites renforcés par fibres de lin. Deuxtechniques expérimentales sont mises en oeuvre : la calorimétrie différentielle à balayage (DSC) et l'impédancemètre de type Novocontrol. Nous concluons que les fibres de lin seules dans le composite sont moinshydrophiles que celles incorporées avec des fibres de carbone, ce qui explique la meilleure adhérencefibres/matrice dans le premier cas.

In ambito di ricerca (clinica e sportiva), la necessità di sviluppare un approccio ‘multilaterale’ (qualitativo e quantitativo) che caratterizzi matematicamente la traiettoria tri-dimensionale di una variabile fisica assolutamente importante ma spesso dimenticata, quale il centro di massa corporeo (CMC) (ovvero, il punto immaginario assimilabile al corpo umano in cui si suppone che tutte le masse corporee stiano concentrate), diviene oggi sempre più impellente e quanto mai urgente. Pertanto l’obiettivo di questo dottorato, perseguito tramite un differente utilizzo delle classiche metodologie biomeccaniche, è rappresentare le grandezze cinematiche che descrivono il movimento dei segmenti corporei e del suddetto CMC nel tempo e nello spazio. Per conseguire questo traguardo si sono pensati e realizzati due diversi progetti. Con il primo progetto si sono previsti: a) lo sviluppo di un metodo matematico quantitativo (Serie di Fourier) per descrivere e rappresentare graficamente la traiettoria tri-dimensionale del CMC durante la locomozione su treadmill (la cosiddetta Impronta Digitale Locomotoria, specifica per soggetto/popolazione); b) la caratterizzazione della simmetria nella traiettoria del CMC (il cosiddetto Indice di Simmetria); infine, c) la costituzione di un database di valori normali (coefficienti di equazioni) in un insieme piuttosto esteso di condizioni, al variare di sesso (maschi versus femmine), età (dai 6 ai 65 anni), tipologia di locomozione (marcia versus corsa), velocità e pendenza (piano, salita e discesa). Questo database iniziale rappresenta il parametro principale di riferimento per la locomozione sana. Attraverso questo studio è stato ampiamente dimostrato che la locomozione umana risulta genericamente asimmetrica. Nello specifico: 1) tra maschi e femmine non si sono riscontrate differenze significative; 2) indipendentemente da età e pendenza, le velocità più basse, meno naturali e comuni, sono caratterizzate da pattern di Impronte Digitali Locomotorie più variabili. Viceversa, un aumento di velocità è accoppiato con un progressivo e continuo innalzamento del CMC; 3) l’asimmetria destra e sinistra del passo è molto probabilmente correlata sia con l’anatomia (lunghezza della gamba) che con la predominanza dell’arto; in linea con l’ipotesi iniziale, 4) mediamente, la corsa è più asimmetrica della marcia; infine, 5) i bambini e gli anziani presentano maggiori asimmetrie (marcia e corsa): questo è dovuto alla progressiva maturazione del ciclo del cammino (nei bambini) ed alle caratteristiche muscolari e scheletriche dell’apparato locomotore (negli anziani). Pertanto, attraverso una caratterizzazione matematica della traiettoria tri-dimensionale del CMC, si è potuto: a) quantificare il suo spostamento nel tempo e nello spazio; b) individuare l’Impronta Digitale Locomotoria specifica di sesso, età, tipologia di locomozione, velocità e pendenza. Questo importante traguardo permetterà, in un immediato futuro, la comparazione con la situazione di normalità di condizioni di locomozione compromessa o impedita (ad esempio, bambini con paralisi cerebrale infantile, obesi e amputati). Infine, la stima della principali variabili biomeccaniche è risultata fondamentale sia nel descrivere la meccanica di marcia e corsa che nel caratterizzarne la corrispondente impronta locomotoria. Le nostre misure di tali variabili (semplici e complesse), ottenute con metodo discreto (ciclo per ciclo), con l’impiego di una funzione matematica continua (Serie di Fourier) e con l’applicazione di un’equazione predittiva (misura indiretta), soddisfano completamente ed addirittura ampliano la letteratura già esistente. Nel secondo progetto, partendo da uno studio sulla performance dei cavalli, si è cercato di verificare se esiste una correlazione tra simmetrie corporee (statiche e dinamiche) ed economia nella corsa anche in corridori umani variamente allenati (classificati in tre gruppi sulla base del loro miglior tempo nella maratona). Inoltre: a) si sono sviluppati metodi di analisi bi- e tri-dimensionale delle Risonanze Magnetiche per Immagini (regione pelvica ed arti inferiori), impiegate come riferimento per le simmetrie statiche; b) attraverso sia l’Impronta Digitale Locomotoria che l’Indice di Simmetria si sono caratterizzate le simmetrie dinamiche; infine c) l’economia della corsa è stata espressa attraverso il suo reciproco, ovvero il costo metabolico. L’analisi sia bi- che tri-dimensionale delle immagini ha evidenziato differenze davvero esigue in base al livello di allenamento. Positivamente ed indipendentemente dai corridori, si è dimostrato che ad una maggiore simmetria nella regione del ginocchio corrisponde una maggiore simmetria nella regione della caviglia. Inoltre l’analisi delle simmetrie dinamiche ha permesso di osservare che: 1) il CMC si solleva leggermente in funzione della velocità; 2) le asimmetrie destre e sinistre del passo sono principalmente marcate lungo la direzione di movimento e, contemporaneamente, ridotte lungo la direzione verticale. Esse sono strettamente dipendenti dall’anatomia e dall’arto dominante; 3) diversamente da quanto ci si aspettava, sono state comunque evidenziate solamente poche differenze tra i corridori. Negativamente, l’economia della corsa non mostra differenze significative tra i gruppi testati. Perciò, diversamente dall’ipotesi iniziale, non è stata evidenziata l’esistenza di alcuna relazione tra le simmetrie corporee e l’economia della corsa, quanto piuttosto solo la presenza di una discreta variabilità in simmetria statica e dinamica. Infine, l’analisi di bioenergetica (treadmill versus pista) e biomeccanica (variabili semplici/complesse e variabilità spazio/temporale del CMC) della corsa ha evidenziato la presenza solamente di poche differenze dovute al livello di allenamento dei soggetti studiati.
In both research laboratory and sport/clinical settings, it becomes very important to develop a ‘multilateral approach’ (qualitative and quantitative) to fully describe the individual behaviour of the centre of mass of the human body (BCOM) (i.e. the imaginary specific point at which the body behaves as if its masses were concentrated) over time and space. Consequently, the aim of this doctorate is to describe kinematic variables of the BCOM in varying locomotion conditions. This purpose, focusing on the BCOM as the investigation object fulfilling such a need, has been achieved through a different use of classic biomechanical procedures. In effect, two different studies were carried out. The first project sought: a) to develop a mathematical method (Fourier Series) which could describe and graphically represent each individual (subject or population) gait signature (i.e. Digital Locomotory Signature, a global index of the BCOM dynamics) during locomotion on a treadmill; b) to assess the symmetry (i.e. Symmetry Index) in each movement direction, along the BCOM trajectory, between the two stride phases; finally, c) to build up an initial comprehensive database of ‘healthy values’ (equation coefficients) in a set of different conditions considering gender (males versus females), age (from 6 to 65 years), gait (walking versus running), speed and gradient (level, uphill and downhill). Although only slight gender differences were found, human ‘healthy’ gait is rather asymmetrical. To be precise: 1) the lowest speeds have the most peculiar signature independently of age and gradient: indeed, these speeds are not so completely natural and common. However, if speed increases, the BCOM raises in such a way that its corresponding 3D contour becomes more regular; 2) right and left sides of the stride are quite asymmetrical (i.e. in the forward direction). Globally, this asymmetry is probably related both to anatomy (i.e. leg length) and which hand you use (i.e. right-handedness); 3) on average, the symmetry pattern is slightly lower in running gaits; and as expected, 4) young children and elderly adults are the most asymmetrical subjects, independently of testing conditions: while, during the early stages of life, this global asymmetry could be ascribed to the process of gait development, old age asymmetries are probably due to structural wearing down of the musculoskeletal system. Importantly, the mathematical methodology used here, by analysing even subtle changes in the 3D BCOM trajectory: a) characterizes its displacements over both time and space; b) quantitatively describes the individual gait signature; and c) represents the basis for the evaluation of gait anomaly/pathology (e.g. children with cerebral palsy, obese people and amputees). Finally, knowing the main biomechanical variables becomes fundamental both to fully describe the mechanics of walking and running and to extract and characterize the individual gait signature. In effect, our measurements (discrete method versus continuous mathematical function, and direct versus indirect measurement) of both simple and complex variables wholly confirm, complete and amplify previous literature data. Similarly to what previously demonstrated in horse performances, the second project tried: a) to verify both static anatomical and kinematic functional symmetries as important and relevant indicators of running economy (i.e. the reciprocal of metabolic cost) in humans featuring different running levels (i.e. occasional, skilled and top runners categorized primarily upon their best marathon time); b) to develop imaging based bi- and three-dimensional methods to analyse static symmetries recorded by Magnetic Resonance Imaging (lower limbs and pelvic area); c) to describe the kinematic symmetries defining both the Digital Locomotory Signature and the Symmetry Index; finally, d) to investigate running economy as a performance determinant. In effect, both the 2D/3D analysis of static symmetries highlight very few differences among runners; however, a strong relationship between ankle and knee areas has been underlined in all runners. Furthermore, independently of training ability: as expected, 1) the BCOM raises and lifts slightly as a function of running speed; 2) right and left steps are mostly asymmetrical in the forward direction and symmetrical in the vertical direction (i.e. combined action of gravity and ground reaction force); 3) differently to what was expected, slight differences have been found among runners. On the whole, the asymmetry is probably related both to anatomy and handedness. Other than that, no running economy differences were found. In conclusion, while a relationship between symmetries and running economy has not been found, significant results have however been underlined in each trial (static and dynamic symmetries). Finally, the deep investigation of both bioenergetics (treadmill versus over-ground) and biomechanics (simple/complex variables and spatial/temporal variability of the BCOM) of running has highlights only little (significant) differences among groups.

The aim of this novel experimental study is to investigate the behaviour of a 2m x 2m model of a masonry groin vault, which is built by the assembly of blocks made of a 3D-printed plastic skin filled with mortar. The choice of the groin vault is due to the large presence of this vulnerable roofing system in the historical heritage. Experimental tests on the shaking table are carried out to explore the vault response on two support boundary conditions, involving four lateral confinement modes. The data processing of markers displacement has allowed to examine the collapse mechanisms of the vault, based on the arches deformed shapes. There then follows a numerical evaluation, to provide the orders of magnitude of the displacements associated to the previous mechanisms. Given that these displacements are related to the arches shortening and elongation, the last objective is the definition of a critical elongation between two diagonal bricks and consequently of a diagonal portion. This study aims to continue the previous work and to take another step forward in the research of ground motion effects on masonry structures.

The principal aims of this research have been the development of photogrammetric techniques for the measurement of anisotropic deformation in uniaxially loaded cylindrical specimens. This has been achieved through the use of calibrated cameras and the application of edge detection and multiple view geometry. The techniques have been demonstrated at quasi-static strain rates, 10^-3 s^-1, using a screw-driven loading device and high strain rates, 10^3 s^-1, using Split Hopkinson Bars. The materials that have been measured using the technique are nearlyisotropic steel, anisotropic cross-rolled Ti-6Al-4V and anisotropic clock-rolled commercially pure Zr. These techniques allow the surface shapes of specimens that deform elliptically to be completely tracked and measured in situ during loading. This has allowed the measurement of properties that could not have been recorded before, including true direct stress and the ratio of transverse strains in principal material directions, at quasi-static and elevated strain rates, in tension and compression. The techniques have been validated by measuring elliptical prisms of various aspect ratios and independently measuring interrupted specimens using a coordinate measurement machine. A secondary aim of this research has been to improve the characterisation of the anisotropic mechanical properties of cross-rolled Ti-6Al-4V using the techniques developed. In particular, the uniaxial yield stresses, hardening properties and the associated anisotropic deformation behaviour along the principal material directions, have all been recorded in detail not seen before. Significant findings include: higher yield stresses in-plane than in the through-thickness direction in both tension and compression, and the near transverse-isotropy of the through-thickness direction for loading conditions other than quasi-static tension, where significant anisotropy was observed.

Ces travaux concernent le developpement d'une methode de mesure optique basee sur l'interferometrie holographique pour analyser le comportement dynamique de structures. Le systeme developpe permet a la fois la mesure simultanee des trois composantes des deplacements de la structure et l'enregistrement ultra-rapide d'une serie d'interferogrammes generes par un laser a impulsions multiples. L'acquisition des deplacements tridimensionnels est basee sur l'enregistrement de trois interferogrammes ayant des faisceaux d'illumination non coplanaires, l'evaluation quantitative de chaque interferogramme s'appuyant sur la technique du decalage de phase. Nous avons mis au point une methode originale de multiplexage spatial des hologrammes qui permet de conserver exactement la meme vue de l'objet pour chacun des trois interferogrammes et donc d'attribuer sans ambiguite a chaque point analyse les trois mesures de phase. Les mesures effectuees sur un cylindre en vibration sont tres bien correlees avec les resultats obtenus par le calcul et confirment la grande sensibilite de la methode et sa fiabilite. Le systeme d'enregistrement ultra-rapide a ete developpe avec un laser a rubis delivrant quatre impulsions dans un intervalle de 800 s. La separation des enregistrements sur la plaque holographique est realisee par deviation des faisceaux de reference grace a des modulateurs acousto-optiques. Pour effectuer le traitement de ces donnees, nous avons examine theoriquement et experimentalement une methode de decomposition modale des reponses dynamiques mesurees par le systeme holographique. Les premiers resultats obtenus sont prometteurs et ouvrent de nouvelles perspectives d'application pour cette methode

Ce travail a pour cadre une collaboration entre le LMA et Thales Alenia Space. Nous nous intéressons au comportement des structures flexibles et plus particulièrement des mètres rubans qui ont la particularité de pouvoir, grâce à l'aplatissement de la section, s'enrouler ou développer des pliages localisés. Une première thèse a permis d'une part la mise au point d'un nouveau type de mètre ruban au déroulement maîtrisable thermiquement et d'autre part le développement d'un modèle plan de poutre à section flexible. Dans le travail de thèse présenté ici, nous proposons une version étendue de ce modèle adaptée à la simulation du comportement dynamique tridimensionnel des mètres rubans en grands déplacements et en grandes rotations. Ce modèle est dérivé de la théorie des coques et repose sur l'introduction d'hypothèses cinématiques et sthéniques adaptées. La déformation de la section est caractérisée par celle de sa ligne moyenne qui peut se déformer dans son plan par flexion et torsion mais non par extension, ainsi que hors de son plan par gauchissement de torsion. Les fortes variations de forme de la section dans son plan peuvent alors être décrites par une cinématique de type Elastica, tandis qu'une cinématique de type Vlassov est utilisée pour définir le gauchissement dans le repère local attaché à la section. Le modèle unidimensionnel est obtenu par intégration sur la section des expressions de la théorie des coques, une approche énergétique permet ensuite de formuler le problème associé qui est résolu grâce au logiciel de modélisation par éléments finis COMSOL.

L’objectif de ce travail porte sur le développement d’un modèle d’interaction fluide-structure adapté à la dynamique des éoliennes de grandes tailles avec des pales flexibles qui se déforment de manière significative sous l’effet de la pression exercée par le vent. Le modèle développé est basé sur une approche efficace d’IFS partitionnée pour un fluide incompressible et non visqueux en interaction avec une structure flexible soumise a des grandes transformations. Il permet de fournir une meilleure estimation de la charge aérodynamique et de la réponse dynamique associée du système (pales, mat, attachements, câbles) avec un temps de calcul raisonnable et pour des simulations sur des longues périodes. Pour la modélisation structurale, un élément fini de type solide 3D est développé pour l’étude dynamique des pales d’éolienne soumises à des grands déplacements et des grandes rotations. Une amélioration du comportement en flexion est proposée par l’introduction des degrés de liberté en rotation et l’enrichissement du champ de déplacements afin de décrire plus précisément la flexibilité des pales. Cet élément solide est apte de capter des modes de hautes fréquences qui peuvent s’avérer néfastes pour la stabilité du calcul. Deux techniques sont donc proposées pour les contrôler : la régularisation de la matrice masse et le développement des schémas d’intégration robustes de conservation et de dissipation d’énergie. Les chargements aérodynamiques sont modélisés en utilisant la Panel Method. Il s’agit d’une méthode aux frontières, relativement rapide par rapport à la CFD mais suffisamment précise pour calculer la distribution de la pression exercée sur la pale. Les modèles fluide et structure interagissent via un algorithme de couplage partitionné itératif dans lequel des considérations particulières sont prises en compte dans le contexte des grandes transformations. Dans un effort visant à instaurer un indicateur de fatigue dans la méthodologie proposée, des câbles précontraints sont introduits reliant le mat de l’éolienne au support. Une nouvelle formulation complémentaire en termes de contraintes est ainsi développée pour l’analyse dynamique des câbles 3D en comportement élasto-visco-plastique. Chaque méthode proposée a été d’abord validée sur des cas tests pertinents. Par la suite, des simulations numériques d’éoliennes avec des pales flexibles sont effectuées en vue d’affiner la compréhension de leur comportement dynamique et l’intérêt que la flexibilité des pales peut apporter à leur fonctionnement
In this work, a numerical model of fluid-structure interaction is developed for dynamic analysis of giant wind turbines with flexible blades that can deflect significantly under wind loading. The model is based on an efficient partitioned FSI approach for incompressible and inviscid flow interacting with a flexible structure undergoing large transformations. It seeks to provide the best estimate of true design aerodynamic load and the associated dynamic response of such system (blades, tower, attachments, cables). To model the structure, we developed a 3D solid element to analyze geometrically nonlinear statics and dynamics of wind turbine blades undergoing large displacements and rotations. The 3D solid bending behavior is improved by introducing rotational degrees of freedom and enriching the approximation of displacement field in order to describe the flexibility of the blades more accurately. This solid iscapable of representing high frequencies modes which should be taken under control. Thus, we proposed a regularized form of the mass matrix and robust time-stepping schemes based on energy conservation and dissipation. Aerodynamic loads are modeled by using the 3D Vortex Panel Method. Such boundary method is relatively fast to calculate pressure distribution compared to CFD and provides enough precision. The aerodynamic and structural parts interact with each other via a partitioned coupling scheme with iterative procedure where special considerations are taken into account for large overall motion. In an effort to introduce a fatigue indicator within the proposed framework, pre-stressed cables are added to the wind turbine, connecting the tower to the support and providing more stability. Therefore, a novel complementary force-based finite element formulation is constructed for dynamic analysis of elasto-viscoplastic cables. Each of theproposed methods is first validated with differents estexamples.Then,several numerical simulations of full-scale wind turbines are performed in order to better understand its dynamic behavior and to eventually optimize its operation

碩士
國立臺灣科技大學
建築系
91
With the commercialization of 3D laser scanner, securing 3D digital data of contour of large objects has become possible. Using data obtained from real object has the characteristics of real time record and on-site record, which meets the information requirement of construction project in progress. This research explores the feasibility and restriction of applying 3D scan data in the displacement analysis occurred to construction components and activities. The study was made to an on-going construction site emphasizing retaining wall supporting system and steel structure system, during the period of foundation excavation. A Cyrax 2500 3D Laser Scanner was used to retrieve data. Point clouds, which were collected through a long period of time, are analyzed through Cyclone compilation program using separation, merging, deconstruction, reconstruction, and measurement methods. An exemplification was made to a building in the campus of National Taiwan University of Science and Technology (NTUST). After data collection and scan operation for 71 weeks, the geometric information of structural configuration and building enclosure was retrieval. Four types of models were used in the analysis and test: 1) points cloud model, 2) points cloud construction plane model, 3) points cloud construction segmentation model, and 4) acquisition single point information model. The models facilitated visual display of construction displacement in point clouds. This study enables a monitoring of 1.6 cm displacement of construction components located 56 meter away. The information retrieved from real objects can record as-built situation almost in real-time, which can meet the information demands of a construction process.

碩士
國立中正大學
通訊工程研究所
101
In an indoor environment, where GPS signal is not available, localization typically relies on triangulation or fingerprint (or radio map) algorithms. These algorithms require the availability of three or more anchor points (or reference points). In this thesis, we propose a novel localization algorithm, which can derive the location of moving users with high accuracy based on measuring the technologically feasible displacement vector in the environment where only one anchor point is needed. The proposed localization algorithm can locate a user in a 3-dimensional space and has been tested on a smartphone to verify its feasibility and accuracy.

碩士
國立臺灣科技大學
營建工程系
105
Taiwan has become highly urbanized and densely populated. To build higher building, deep excavations are one of the crucial procedures. But deep excavations are subject to risks. To prevent the risks, the engineer uses construction monitoring systems, like inclinometers and surface settlement mark, for monitoring the construction site. However, the conventional construction monitoring systems couldn’t measure the object with 3-dimensional deformation data. On the other hand, laser scanning reforms the monitoring systems to 3D world. Because of its ability to acquire space data in short time, there are some cases using 3D laser scanning to monitor construction sites. This research introduces 3D laser scanning to monitor displacement of diaphragm walls in deep excavation. At first, we design an algorithm using point clouds to estimate the displacement of diaphragm walls. And to implement the algorithm, we develop a plugin of an open source software CloudCompare with C++. What’s more, to verify our algorithm, we apply the algorithm in an excavation project to estimate the displacement of diaphragm walls. It shows that the displacement our method estimates is larger than expected, although the program could calculate the displacement. So, we manage to examine the procedure used in the project to improve it. Further studies are necessary to realize the 3D monitoring method.

碩士
國立中興大學
土木工程學系所
105
Lishan is one important observation area to prevent the occurrences of landslides in Taiwan. In order to expel deeper underground water inside the area, various drainage well''s were established in Lishan. Drainage well''s is often set up in landslide area to reduce underground water accumulation more efficiently, so as to enhance the stability of slope land. On the other hand, the occurrence of earth slide may also cause the deformation of drainage well''s. Hence, the observation on the shape of drainage well''s is also an effective measure to determine whether there are earth slides in the area. This study installed four Raspberry Pi around one of the drainage well''s, drainage well''s No.W6, in Lisan and utilized OpenCV to interpret the signals inside the drainage well''s. There were four levels in this drainage well''s. The four Raspberry Pi were assigned with different serial number, Pw6-B1, Pw6-B2, Pw6-P3, and Pw6-B4, and were sent to different level to monitor the signals at each level respectively. Through both lab testing and on-site testing, the study observed the signals for a long period and obtained stable statistics, which was further discussed after conducting data analysis. From observing the changes in full-time trend and daily average trend, the study was able to determine the changes of this drainage well''s. The drainage well''s displacement observation system by computer vision in the future may become an early warning reference for landslides in Lishan area.

This dissertation aims to demonstrate the feasibility of direct infarct visualization using 3D medical ultrasound. The dissertation proceeds by providing the first ever demonstration of fully-sampled 3D ultrasonic speckle tracking using raw B-Mode data of the heart. The initial demonstration uses a Cramer-Rao lower bound limited displacement estimator. The dissertation then proceeds to develop an implementable method for biased time-delay estimation. Biased time-delay estimation is shown to surpass the traditional limits described by the Cramer-Rao lower bound in a mean square error sense. Additional characterization of this new class of estimator is performed to demonstrate that with easily obtainable levels of prior information it is possible to estimate displacements that do surpass the Cramer-Rao lower bound. Finally, using 2D and 3D realizations of biased displacement estimation (Bayesian speckle tracking) the passive strain induced in the ventricle walls during atrial systole is shown to be sufficient to distinguish healthy and chronically infarcted myocardium.

Dissertation

碩士
國立交通大學
機械工程系所
106
The study proposed and applied the innovative confocal optical technique with varifocal lens on confocal displacement sensor system. High speed scanning methology of profile measurement for transparent object was developed. Some typical experiments of transparent object configuration measurement are executed and demonstrated. First of all, the thickness measurement of cover glass and slide glass was illustrated and discussed. Varifocal lens driven by current and focal power mode were adopted for comparision. LabVIEW program was developed to detect two peaks from collected confocal signal and transforms it into two groups of displacement data for calculating the thickness of the transparent objects based on the corrected parameters such as optical reflection parameters, etc.. Secondly, the compensating rules in dealing with the offset error of confocal signal was discoveried. The influence of temperature in current mode was detected and studied while observing the relative changes of confocal signals in different temperature ocnditions. In third part, the study proposed the continuously scanning method by using analog triangle mode assisted by DAQ system. Measuring the data of multiple points based on LabVIEW improves the scanning speed while using 20 Hz triangle driving current with this method. The scan speed could reach near 50 ms per scan point, which increases 2.6 times in speed compared with former method. Based on the above methods, the measurement of step-height of stair configuration object with 2D tracjectory was tested as illustrated samples. Finally the surface profile of convex glass lens by continuously multi-point scanning method was studied and discussed. The results of the experiment show that after thecompensation process of regulating tilt of the measuring platform, the center of the lens can be found. The evaluated results demonstrate the improved and practical performance of the confocal displacement sensor system with varifocal lens. The function and precision of the optical measurement system was also available for applying to the transparent object on geometrical configuration measurement applications.

The backdrop for this research paper is the tunnelling that is currently nearing completion in the Epirus region of Northern Greece, as part of the Egnatia Odos Highway construction. Highly deformed and altered sediments and low grade rock masses dominate the near surface environment creating a variety of technical challenges for tunnelling. Accurate equivalent rock mass performance reductions for tunnels in these materials is complicated by geomorphologic peculiarities such as those found in Flysch materials. The mechanisms of rock-support interaction related to face or near-face reinforcement systems are poorly understood at this time. As well, the mechanics of weak rock materials in the complex deformation regime in advance of a tunnel face are not robustly integrated into current 2D design models. Design decisions are currently possible using empirical techniques and simplified models, but a true optimized and mechanicsbased design process for the various support technologies are not fully developed. This research addresses elements of such issues, such as: use of the Longitudinal Displacement Profile (LDP) of the Convergence-Confinement method of tunnel design, relating 2D numerical models to their distance from the face using the size of the plastic zone as an indicator, near face tunnel support analysis in weak rock masses, boundary condition assessment for numerical modelling of such weak rock masses, the influence of plasticity zones surrounding tunnel excavations, and modelling optimization techniques for weak rock tunnelling in order to optimize the design of such underground structures and better predict near-face deformation and yield development. This work involved the use of 2D and 3D numerical models of tunnel sequencing for numerical simulation of composite material behaviour and sequential tunnel deformation response.
Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2009-09-01 08:46:30.537

Yes
In this study, a new three-dimensional (3-D) model was developed to provide better understanding of the mechanism for wave-induced seabed response around mono-pile. Based on poro-elastic theory, the fully dynamic (FD) formulations were adopted in the present model to simulate pore water pressure, soil stresses, displacements of both soil and mono-pile. Good agreement between numerical simulation and experimental results was obtained. Based on parametric study, numerical results indicated: (1) wave diffraction and reflection have significant effects on pore water pressure and soil displacements around mono-pile; (2) the most sensitive position for seabed parameter to pore water pressure around mono-pile locates in front of mono-pile while the least sensitive position is at the position of angle 3π/4 with respect to the incident wave direction; and (3) the increase of mono-pile horizontal displacement corresponds to the increase of wave height and the decrease of seabed Young's modulus.
National Science Fund for Distinguished Young Scholars (51425901), the National Natural Science Foundation of China (51209082, 51379071, 41176073), the Specialized Research Fund for the Doctoral Program of Higher Education of China (20120094120006, 20130094110014), the 111 project (B12032), the 333 project of Jiangsu Province (2013Ⅲ-1882)

碩士
國立成功大學
土木工程學系碩博士班
101
This thesis uses the digital-image correlation experiment to find the displacement filed, which is used to discuss the three-dimensional (3-D) effect of crack problems. In the experiment, specimens with four different thicknesses are used to compare the experimental results due to the plate thickness effect, and finite element method (FEM) results are then used to compare with the experimental results. The comparisons indicated that the displacement contour is presented a smoother situation for the thinner specimens. Additionally, the thesis also uses the FEM to analyze the stress behavior between the mid-plane and edge-plane, and the comparisons with different Poisson’s ratios are presented in this study. For the mode-I crack behavior, the comparisons indicate that the stress is gradually reduced as the location approaches to the plate surface, and the stress decreases as the Poisson’s ratio increases. In this experiment, the crack is set to the Mode-I type, but this thesis also displays the Mode-II results of the experiment.

碩士
國立臺灣大學
土木工程學研究所
104
In this stage, the analysis of tunnels is based on the study of “stress-strain relationship around a hole in an elasto-plasticity media” and “closed convergence curve concept”. These theories of underground excavation are mostly proposed by European and American countries. Because of their old geological ages and high strength and excellent cement of rock mass, the tunnels there can be operated stably as long as the construction is fully completed. However, the tunnels constructed in Japan and Taiwan, are deformed to give some impacts to their operation, due to the young geological ages of Japan and Taiwan. Thus, the theories above cannot be fully applied in the cases in Taiwan, and how to keep the operation of tunnels stable becomes one important issue in tunnel engineering of Taiwan. In the tunnel, there are different kinds of defect can be observed on the lining, for the reason that there are various kinds of way to detect the tunnel. The most common issue in the operation of tunnels is how to deal with cracks on the linings. Since the patterns of cracks seem related to the relevant causes, it is generally viewed as an effective way to deal with the cracks for maintaining tunnels in operation by observing, recording and explaining the pattern and development of cracks. In this study, one finite element model with one tunnel and the surrounding rock mass is proposed to survey the relationship between the patterns of cracks and different conditions of displacements of lining induced by the movements of surrounding rock mass. Besides, the impacts of different cross-section geometry and length of tunnels, different number of construction joints and stiffness of surrounding rock mass to the development of cracks are investigated, and one case study is demonstrated. The results show that the different conditions of displacements of surrounding rock mass would induce distinct patterns of cracks of linings, and the crack patterns would not alter caused by different condition of tunnels. The case study also shows that the patterns and the positions of cracks on the model in this study are consistent with the in-situ record.

碩士
國立聯合大學
土木與防災工程學系碩士班
99
Based on the theory of elasticity, the solutions of displacements and stresses subjected to a 3D point load in a vertical transversely isotropic half-space are generated in this thesis. The stress-strain relationships, the displacement-strain relationships, and the equilibrium equations are integrated to constitute the government equations. The analytical solutions are derived by performing the double Fourier integral transforms, and the variation of parameters. Co-operating the boundary conditions at infinity, the integral expressions of displacement in the full-space of Fourier transformed domain can be obtained. Then, replacing the co-ordinate z of the general and homogeneous solutions in the full-space by z-h, the particular and homogeneous solutions to constitute the general solution of the half-space can be constructed. Sequentially, applying the stress free surface boundary conditions (z=0,σzz=τyz=τzx=0), the three undetermined coefficients can be obtained. Eventually, the double inverse Fourier integral transforms and residue calculus are utilized to integrate the contours. The parametric study reveals that the vertical displacement owing to the point load in the full-space is equal to Yang’s solution (2009) when the dip angle of stratum is 90°. The vertical displacement in the half-space is the identical with Mindlin’s solution (1936) when the medium is isotropic. However, the calculated values have trace imaginary numbers when the half-space is vertical transversely isotropic. The present solution is compared with Dai’s solution (2010), and it is found that her solution also have the same problem. In addition, Dai’s (2010) solution has no trend for the vertical displacement should decrease as increasing of z when x and y are fixed. As for the obtained results have trace imaginary numbers might be induced by the huge operation in this study. Furthermore, the characteristic equation contains imaginary numbers in the radical, and it could cause errors during the numerical calculations. Therefore, a further investigation on this topic is required.

碩士
國立交通大學
土木工程學系
99
The failure of a foundation in soil/rock is often caused by over loading or large displacements. This fact is particularly important to analyze stresses and displacements when structures impose very large loads on the underlying soil/rock. However, it is also important for understanding the influence of the "anisotropy" of soil/rock on stresses, strains and displacements. Based on the orientation of geological structures or direction of planes of elastic symmetry, Elastic materials can be divided into general anisotropic, orthogonal or transversely isotropic materials. The nature of anisotropy of soils/rocks is caused by depositing via sedimentation over a long period of time, cutting by regular discontinuities, such as cleavages, foliations, stratifications and joints. Anisotropic soils/rocks are commonly modeled as transversely isotropic materials based on the practical engineering considerations. Nevertheless, the inclination of planes of elastic symmetry is not always horizontal, and hence, this thesis extending the approach proposed by Hu (2009) to study the closed form solutions for displacements in an half space with vertical transversely isotropy subjected to a surface 3D point load. To obtain the closed form solutions, the double Fourier transform was used to reduce the partial differential equations to ordinary differential equations, firstly. Then, the solutions of displacement and stress in Fourier domain can be determinednd from the boundary conditions. Finally, the closed form solutions for stresses and displacements in a vertical transversely isotropic half space material subjected to a 3D point load can be obtained using the double inverse Fourier transform and residue theorem. The present closed-form solutions demonstrate that the material anisotropy could affect the displacements and stresses in a vertical transversely isotropy. The illustrative examples show that the calculated displacements in a horizontal transversely isotropic half space are the same/similar as those presented by Hu (2009) and Ding et, al., (2006). Hence, the closed form solutions for stresses and displacements in a vertical transversely isotropic half space can be reasonably solved if the all of residue of integrals in the inverse Fourier domain can be determined exactly.