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  • 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.
1

Space carving de séquences Multi-vues Vidéo plus, Profondeur pour la représentation et la transmission de contenus deTV3D et FTV / Space Carving multi-view video plus depth sequences for representation and transmission of 3DTV and FTV contents

Alj, Youssef 16 May 2013 (has links)
La vidéo 3D a suscité un intérêt croissant durant ces dernières années. Grâce au développement récent des écrans stéréoscopiques et auto-stéréoscopiques, la vidéo 3D fournit une sensation réaliste de profondeur à l'utilisateur et une navigation virtuelle autour de la scène observée. Cependant de nombreux défis techniques existent encore. Ces défis peuvent être liés à l'acquisition de la scène et à sa représentation d'une part ou à la transmission des données d'autre part. Dans le contexte de la représentation de scènes naturelles, de nombreux efforts ont été fournis afin de surmonter ces difficultés. Les méthodes proposées dans la littérature peuvent être basées image, géométrie ou faire appel à des représentations combinant image et géométrie. L'approche adoptée dans cette thèse consiste en une méthode hybride s'appuyant sur l'utilisation des séquences multi-vues plus profondeur MVD (Multi-view Video plus Depth) afin de conserver le photo-réalisme de la scène observée, combinée avec un modèle géométrique, à base de maillage triangulaire, renforçant ainsi la compacité de la représentation. Nous supposons que les cartes de profondeur des données MVD fournies sont fiables et que les caméras utilisées durant l'acquisition sont calibrées, les paramètres caméras sont donc connus, mais les images correspondantes ne sont pas nécessairement rectifiées. Nous considérerons ainsi le cas général où les caméras peuvent être parallèles ou convergentes. Les contributions de cette thèse sont les suivantes. D'abord, un schéma volumétrique dédié à la fusion des cartes de profondeur en une surface maillée est proposé. Ensuite, un nouveau schéma de plaquage de texture multi-vues est proposé. Finalement, nous abordons à l'issue ce ces deux étapes de modélisation, la transmission proprement dite et comparons les performances de notre schéma de modélisation avec un schéma basé sur le standard MPEG-MVC, état de l'art dans la compression de vidéos multi-vues. / 3D videos have witnessed a growing interest in the last few years. Due to the recent development ofstereoscopic and auto-stereoscopic displays, 3D videos provide a realistic depth perception to the user and allows a virtual navigation around the scene. Nevertheless, several technical challenges are still remaining. Such challenges are either related to scene acquisition and representation on the one hand or to data transmission on the other hand. In the context of natural scene representation, research activities have been strengthened worldwide in order to handle these issues. The proposed methods for scene representation can be image-based, geometry based or methods combining both image and geometry. In this thesis, we take advantage of image based representations, thanks to the use of Multi-view Video plus Depth representation, in order to preserve the photorealism of the observed scene, and geometric based representations in order to enforce the compactness ofthe proposed scene representation. We assume the provided depth maps to be reliable.Besides, the considered cameras are calibrated so that the cameras parameters are known but thecorresponding images are not necessarily rectified. We consider, therefore, the general framework where cameras can be either convergent or parallel. The contributions of this thesis are the following. First, a new volumetric framework is proposed in order to mergethe input depth maps into a single and compact surface mesh. Second, a new algorithm for multi-texturing the surface mesh is proposed. Finally, we address the transmission issue and compare the performance of the proposed modeling scheme with the current standard MPEG-MVC, that is the state of the art of multi-view video compression.
2

FOOT-TRANSMITTED VIBRATION: EXPOSURE CHARACTERISTICS AND THE BIODYNAMIC RESPONSE OF THE FOOT

Goggins, Katie A. 30 July 2013 (has links)
Research shows miners can be exposed to foot-transmitted vibration (FTV) when operating various pieces of underground mining equipment, and case reports suggest workers are experiencing symptoms similar to those of hand-arm vibration syndrome in their feet. A field study was conducted to measure and document FTV exposure associated with operating underground mining equipment, and probable health risks were determined based on both ISO 2631-1 (1997) for WBV and ISO 5349-1 (2004) for HAV. Seventeen participating operator’s also reported musculoskeletal discomfort. Seventeen male participants ranging between 24-61 years of age, with an average height and mass of 175.0cm and 88.2kg volunteered for the study. Seventeen pieces of equipment were tested; 1 locomotive, 1 crusher, 9 bolter drills (4 scissor platforms, 2 Maclean, 2 Boart/basket, and 1 RDH), and 6 jumbo drills. Including all seventeen pieces of underground mining equipment, the vibration acceleration ranged from 0.13-1.35m/s2 with dominant frequencies between 1.25-250Hz according to ISO 2631-1. According to ISO 5349-1 vibration acceleration ranged from 0.14-3.61m/s2 with dominant frequencies between 6.3-250Hz. Furthermore, the magnitude of FTV measured on the jumbo drills with grated platforms (#5 and #6) was less than FTV measured from the jumbo drills with, solid metal surfaces. Additionally, twelve of the seventeen equipment operators indicated a complaint of discomfort in their lower body (specifically at the level of the knee or lower). The health risk analysis based on ISO 2631-1 indicated that one operator (bolter drill #9) was exposed to vibration above the criterion value, while the health risk analysis based on ISO 5349-1 indicated iv that two operators (jumbo drill #1 and bolter drill #1) were exposed to vibration above the criterion value. Operators reported very severe or severe discomfort; however, the same operators were not the operators of the equipment with FTV exposure levels above the ISO standards, leaving evidence to suggest that the standards are not properly assessing injury risk to vibration exposure via the feet. Future research is needed to develop a standard specific for FTV and to determine the link between early musculoskeletal injury reporting and the onset of vibration white foot. To do so, a better understanding of the biodynamic response of the foot to FTV is needed. A laboratory study was conducted to 1) measure and document transmissibility of FTV from (a) floor-to-ankle (lateral malleolus), and (b) floor-to-metatarsal, during exposure to six levels of vibration (25Hz, 30Hz, 35Hz, 40Hz, 45Hz, and 50Hz) while standing, and 2) to determine whether independent variables (vibration exposure frequency, mass, arch type) influence transmissibility (dependent variable) through the foot. A two-way repeated measures analysis of variance (ANOVA) was conducted. There was a significant interaction between transmissibility location and exposure frequency (λ = 0.246, F (5,25) = 15.365, p = 0.0001). There were significant differences in mean transmissibility between the ankle and metatarsal at 40Hz [t(29) = 4.116, p = 0.00029], 45Hz [t(29) = 6.599, p = 0.00000031], and 50Hz [t(29) = 8.828, p = 0.000000001]. The greatest transmissibility at the metatarsal occurred at 50Hz and at the ankle (lateral malleolus) transmissibility was highest from 25-30Hz, indicating the formation of a local resonance at each location. v Future research should focus on identifying resonance frequencies at different locations on the feet. This information is needed to develop an exposure guideline to help protect workers from exposure to FTV, and to develop personal protective equipment capable of attenuating harmful FTV exposure frequencies.
3

Specifika ocenění televizní společnosti – ukázka na FTV Prima, spol. s.r.o. / Specifics of valuation of television companies - demonstration on FTV Prima, spol. s.r.o.

Korolev, Alexander January 2016 (has links)
The aim of the graduate work is to identify the specifics of valuation of television companies. The research was conducted on the example of a company FTV Prima, spol. s.r.o. Firstly a detailed financial and strategic analysis has been made with an emphasis not only on the selected company, but also for the entire industry. Then was prepared a package of conclusions and recommendations regarding the valuation of television companies. The last chapter is a brief overview of the identified specifics that should introduce an evaluator to the substance of this issue, prior to the start of valuation work. The work contains a scheme of work with specific television value drivers.
4

Síntese de vistas em depht-image-based rendering (DIBR) / View synthesis with depth-image-based rendering (DIBR)

Oliveira, Adriano Quilião de January 2016 (has links)
Esta dissertação investiga soluções para o problema genérico de geração de vistas sintéticas a partir de um conjunto de imagens utilizando a abordagem Depth-Image-Based Rendering. Essa abordagem utiliza um formato compacto para a representação de imagens 3D, composto basicamente por duas imagens, uma colorida para a vista de referência e outra em tons de cinza com a correspondência de disparidade para cada pixel. Soluções para esse problema beneficiam aplicações como Free Viewpoint Television. O maior desafio é o preenchimento de regiões sem informação de projeção considerando o novo ponto de vista, genericamente denominados holes, além de outros artefatos como cracks e ghosts que ocorrem por oclusões e erros no mapa de disparidade. Nesta dissertação apresentamos técnicas para remoção e tratamento de cada uma das classes de potenciais artefatos. O conjunto de métodos propostos apresenta melhores resultados quando comparado com o atual estado da arte em geração de vistas sintéticas com o modelo DIBR para o conjunto de dados Middlebury, considerando-se as métricas SSIM e PSNR. / This dissertation investigates solutions to the general problem of generating synthetic views from a set of images using the Depth-Image-Based Rendering approach. This approach uses a compact format for the 3D image representation, composed basically of two images, one color image for the reference view and other grayscale image with the disparity information available for each pixel. Solutions to this problem benefit applications such as Free Viewpoint Television. The biggest challenge is filling in regions without projection information considering the new viewpoint, usually called holes, and other artifacts such as cracks and ghosts that occur due to occlusions and errors in the disparity map. In this dissertation we present techniques for removal and treatment of each of these classes of potential artifacts. The set of proposed methods shows improved results when compared to the current state of the art generation of synthetic views using the DIBR model applied to the Middlebury dataset, considering the SSIM and PSNR metrics.
5

The research of strategic alliance after wireless TV enters the digital industry- The case of FTV.

LU, Lien-hsien 27 August 2007 (has links)
In the digital industry, FTV mainly develops three kinds of business: digital TV, network and cell phone. In the aspect of digital TV, there are ¡§Follow Me TV¡¨ and ¡§Fly Vision¡¨; in the aspect of network, there are ¡§Online TV¡¨ and ¡§FTV-beauty.com¡¨ e-commerce website; and in the aspect of cell phone, there are ¡§Cell-phone TV¡¨ and ¡§FTV Master¡¨ monitoring system. This research adopts ¡§semi-structured interview¡¨ and transaction cost theory to study the motive, type and management actions of FTV strategic alliance and evaluate the performance of the strategic alliance. It is found in this research that, after FTV enters the digital industry, the network TV and transmission stations with simpler alliance motives and type have lower performance in management and see less profit. ¡§Fly Vision¡¨ and ¡§Cell-phone TV¡¨ have complicated motives, including market expansion, cost sharing, risk reducing, technology supplementing and competitive advantage increasing; they have achieved relatively stable growth due to the longer time of alliance. ¡§Follow Me TV¡¨ has the five motives of alliance; however, it fails to reach remarkable performance because the viewership rate of digital TV is not clear. ¡§FTV-beauty.com¡¨ and ¡§FTV Master¡¨ also have the five motives of alliance, but the time of market exploitation is relatively shorter, so it has just seen a relatively high growth and its performance will be steady after that.
6

Space carving de séquences Multi-vues Vidéo plus, Profondeur pour la représentation et la transmission de contenus deTV3D et FTV

Alj, Youssef 16 May 2013 (has links) (PDF)
La vidéo 3D a suscité un intérêt croissant durant ces dernières années. Grâce au développement récent des écrans stéréoscopiques et auto-stéréoscopiques, la vidéo 3D fournit une sensation réaliste de profondeur à l'utilisateur et une navigation virtuelle autour de la scène observée. Cependant de nombreux défis techniques existent encore. Ces défis peuvent être liés à l'acquisition de la scène et à sa représentation d'une part ou à la transmission des données d'autre part. Dans le contexte de la représentation de scènes naturelles, de nombreux efforts ont été fournis afin de surmonter ces difficultés. Les méthodes proposées dans la littérature peuvent être basées image, géométrie ou faire appel à des représentations combinant image et géométrie. L'approche adoptée dans cette thèse consiste en une méthode hybride s'appuyant sur l'utilisation des séquences multi-vues plus profondeur MVD (Multi-view Video plus Depth) afin de conserver le photo-réalisme de la scène observée, combinée avec un modèle géométrique, à base de maillage triangulaire, renforçant ainsi la compacité de la représentation. Nous supposons que les cartes de profondeur des données MVD fournies sont fiables et que les caméras utilisées durant l'acquisition sont calibrées, les paramètres caméras sont donc connus, mais les images correspondantes ne sont pas nécessairement rectifiées. Nous considérerons ainsi le cas général où les caméras peuvent être parallèles ou convergentes. Les contributions de cette thèse sont les suivantes. D'abord, un schéma volumétrique dédié à la fusion des cartes de profondeur en une surface maillée est proposé. Ensuite, un nouveau schéma de plaquage de texture multi-vues est proposé. Finalement, nous abordons à l'issue ce ces deux étapes de modélisation, la transmission proprement dite et comparons les performances de notre schéma de modélisation avec un schéma basé sur le standard MPEG-MVC, état de l'art dans la compression de vidéos multi-vues.
7

On the influence of nozzle geometries on supersonic curved wall jets

Robertson Welsh, Bradley January 2017 (has links)
Circulation control involves tangentially blowing air around a rounded trailing edge in order to augment the lift of a wing. The advantages of this technique over conventional mechanical controls are reduced maintenance and lower observability. Despite the technology first being proposed in the 1960s and well-studied since, circulation control is not in widespread use today. This is largely due to the high mass flow requirements. Increasing the jet velocity increases both the efficiency (in terms of mass flow) and effectiveness. However, as the jet velocity exceeds the speed of sound, shock structures form which cause the jet to separate. Recent developments in the field of fluidic thrust vectoring (FTV) have shown that an asymmetrical convergent-divergent nozzle capable of producing an irrotational vortex (IV) has the potential to prevent separation through eliminating stream-wise pressure gradients. In this study, the feasibility of preventing separation at arbitrarily high jet velocities through the use of asymmetrical nozzle geometries designed to maintain irrotational (and stream-wise pressure gradient free) flow is explored. Furthermore, the usefulness of an adaptive nozzle geometry for the purpose of extending circulation control device efficiency and effectiveness is defined. Through a series of experiments, the flow physics of supersonic curved wall jets is characterised across a range of nozzle geometries. IV and equivalent area ratio symmetrical convergent-divergent nozzles are compared across three slot height to radius ratios (H/R): H/R = 0.1, H/R = 0.15, H/R = 0.2. The conclusion of this study is that at low H/R (0.1 and 0.15), there is no significant difference in behaviour between IV and symmetrical nozzles, whilst at high H/R (0.2), the IV nozzles begin separating whilst correctly expanded due to the propagation of pressure upstream from the edge of the reaction surface via the boundary layer. Consequently, it is shown that symmetrical nozzles of equivalent mass flow at high H/R have a higher separation NPR compared to IV nozzles. Specifically, the elimination of favourable, in addition to adverse stream-wise pressure gradients contradicts the expected behaviour of IV nozzles. The separation NPR for nozzles tested in this study, in addition to past studies is subsequently plotted against the throat height to radius ratios (A*/R). This shows that in fact, no previous experiments have shown a higher separation NPR for IV nozzles compared to symmetrical nozzles of equivalent mass flow. The overall outcome is that neither fixed geometry IV, nor adaptive nozzles are justified to maintain attachment, or to improve efficiency. This is because fixed nozzle geometries designed for higher separation NPR do not show any performance deficit when operating at lower NPRs. However, the throat height could be varied to maximise effectiveness (at the expense of mass flow). The contributions to new knowledge made by this study are as follows: the development of a new method of combining shadowgraph and schlieren images to simplify and enhance visualisation of supersonic flows; the use of pressure sensitive paint (PSP) to study the structure of the supersonic curved wall jet before and after separation; the identification of a clear mechanism for the separation of supersonic curved wall jets, valid over a broad range of nozzle geometries (including a clarification of previously unexplained behaviour witnessed in prior studies); the explanation that reattachment hysteresis occurs due to the upstream movement of the point of local separation at full separation (specifically, this explains why certain geometries such as backward-facing steps prevent reattachment hysteresis).
8

Síntese de vistas em depht-image-based rendering (DIBR) / View synthesis with depth-image-based rendering (DIBR)

Oliveira, Adriano Quilião de January 2016 (has links)
Esta dissertação investiga soluções para o problema genérico de geração de vistas sintéticas a partir de um conjunto de imagens utilizando a abordagem Depth-Image-Based Rendering. Essa abordagem utiliza um formato compacto para a representação de imagens 3D, composto basicamente por duas imagens, uma colorida para a vista de referência e outra em tons de cinza com a correspondência de disparidade para cada pixel. Soluções para esse problema beneficiam aplicações como Free Viewpoint Television. O maior desafio é o preenchimento de regiões sem informação de projeção considerando o novo ponto de vista, genericamente denominados holes, além de outros artefatos como cracks e ghosts que ocorrem por oclusões e erros no mapa de disparidade. Nesta dissertação apresentamos técnicas para remoção e tratamento de cada uma das classes de potenciais artefatos. O conjunto de métodos propostos apresenta melhores resultados quando comparado com o atual estado da arte em geração de vistas sintéticas com o modelo DIBR para o conjunto de dados Middlebury, considerando-se as métricas SSIM e PSNR. / This dissertation investigates solutions to the general problem of generating synthetic views from a set of images using the Depth-Image-Based Rendering approach. This approach uses a compact format for the 3D image representation, composed basically of two images, one color image for the reference view and other grayscale image with the disparity information available for each pixel. Solutions to this problem benefit applications such as Free Viewpoint Television. The biggest challenge is filling in regions without projection information considering the new viewpoint, usually called holes, and other artifacts such as cracks and ghosts that occur due to occlusions and errors in the disparity map. In this dissertation we present techniques for removal and treatment of each of these classes of potential artifacts. The set of proposed methods shows improved results when compared to the current state of the art generation of synthetic views using the DIBR model applied to the Middlebury dataset, considering the SSIM and PSNR metrics.
9

Síntese de vistas em depht-image-based rendering (DIBR) / View synthesis with depth-image-based rendering (DIBR)

Oliveira, Adriano Quilião de January 2016 (has links)
Esta dissertação investiga soluções para o problema genérico de geração de vistas sintéticas a partir de um conjunto de imagens utilizando a abordagem Depth-Image-Based Rendering. Essa abordagem utiliza um formato compacto para a representação de imagens 3D, composto basicamente por duas imagens, uma colorida para a vista de referência e outra em tons de cinza com a correspondência de disparidade para cada pixel. Soluções para esse problema beneficiam aplicações como Free Viewpoint Television. O maior desafio é o preenchimento de regiões sem informação de projeção considerando o novo ponto de vista, genericamente denominados holes, além de outros artefatos como cracks e ghosts que ocorrem por oclusões e erros no mapa de disparidade. Nesta dissertação apresentamos técnicas para remoção e tratamento de cada uma das classes de potenciais artefatos. O conjunto de métodos propostos apresenta melhores resultados quando comparado com o atual estado da arte em geração de vistas sintéticas com o modelo DIBR para o conjunto de dados Middlebury, considerando-se as métricas SSIM e PSNR. / This dissertation investigates solutions to the general problem of generating synthetic views from a set of images using the Depth-Image-Based Rendering approach. This approach uses a compact format for the 3D image representation, composed basically of two images, one color image for the reference view and other grayscale image with the disparity information available for each pixel. Solutions to this problem benefit applications such as Free Viewpoint Television. The biggest challenge is filling in regions without projection information considering the new viewpoint, usually called holes, and other artifacts such as cracks and ghosts that occur due to occlusions and errors in the disparity map. In this dissertation we present techniques for removal and treatment of each of these classes of potential artifacts. The set of proposed methods shows improved results when compared to the current state of the art generation of synthetic views using the DIBR model applied to the Middlebury dataset, considering the SSIM and PSNR metrics.
10

Marketingová strategie Společnosti FTV Prima v prostředí českého televizního trhu / The Marketing strategy of FTV Prima s.r.o. in the enviroment of the czech television market

Malá, Kateřina January 2013 (has links)
This thesis focuses on the topic of marketing strategy of FTV Prima s.r.o. in the television market. The main objective of this thesis is the definition of marketing activities and the use of marketing tools by FTV Prima, a company operating nationwide TV broadcast television stations Prima, Prima COOL, Prima Love and Prima ZOOM, leading to a better position in the television market. The theoretical part of the thesis is the application of marketing mix 4P in the television as a media. The practical part is a description of the inner workings of FTV Prima in connection with charting the television market

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