• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6
  • 5
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 20
  • 20
  • 7
  • 7
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 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.
11

Metodika zkoumání rychlých a stochastických mechanických dějů / Methodology of fast and stochastic mechanical process research

Kolomazník, Petr January 2008 (has links)
This diploma thesis deals with the research of fast processes. It delineates technique the process is captured by with following interpretation of the results received. Fast processes are captured using high speed video camera system Olympus i-SPEED 2. The actual object of measuring and examination was an air pistol and its initial velocity.
12

Aplikace vysokorychlostního kamerového systému při testování rotujících pryžových dílů / Application high speed camer during testing rotation rubber parts

Pešek, Jan January 2009 (has links)
This diploma thesis introduces Olympus i-SPEED 2 high speed video camera and its use in the testing of rubber parts. The results gained will be applied to tyre tread development. Two mutually connected high speed cameras were used to record the testing process. Final recordings were put together in order to create panoramic photos.
13

Monitoring fish using passive acoustics

Mouy, Xavier 31 January 2022 (has links)
Some fish produce sounds for a variety of reasons, such as to find mates, defend their territory, or maintain cohesion within their group. These sounds could be used to non-intrusively detect the presence of fish and potentially to estimate their number (or density) over large areas and long time periods. However, many fish sounds have not yet been associated to specific species, which limits the usefulness of this approach. While recording fish sounds in tanks is reasonably straightforward, it presents several problems: many fish do not produce sounds in captivity or their behavior and sound production is altered significantly, and the complex acoustic propagation conditions in tanks often leads to distorted measurements. The work presented in this thesis aims to address these issues by providing methodologies to record, detect, and identify species-specific fish sounds in the wild. A set of hardware and software solutions are developed to simultaneously record fish sounds, acoustically localize the fish in three-dimensions, and record video to identify the fish and observe their behavior. Three platforms have been developed and tested in the field. The first platform, referred to as the large array, is composed of six hydrophones connected to an AMAR acoustic recorder and two open-source autonomous video cameras (FishCams) that were developed during this thesis. These instruments are secured to a PVC frame of dimension 2 m x 2 m x 3 m that can be transported and assembled in the field. The hydrophone configuration for this array was defined using a simulated annealing optimization approach that minimized localization uncertainties. This array provides the largest field of view and most accurate acoustic localization, and is well suited to long-term deployments (weeks). The second platform, referred to as the mini array, uses a single FishCam and four hydrophones connected to a SoundTrap acoustic recorder on a one cubic meter PVC frame; this array can be deployed more easily in constrained locations or on rough/uneven seabeds. The third platform, referred to as the mobile array, consists of four hydrophones connected to a SoundTrap recorder and mounted on a tethered Trident underwater drone with built-in video, allowing remote control and real-time positioning in response to observed fish presence, rather than long-term deployments as for the large and mini arrays. For each array, acoustic localization is performed by measuring time-difference of arrivals between hydrophones and estimating the sound-source location using linearized (for the large array) or non-linear (for the mini and mobile arrays) inversion. Fish sounds are automatically detected and localized in three dimensions, and sounds localized within the field of view of the camera(s) are assigned to a fish species by manually reviewing the video recordings. The three platforms were deployed at four locations off the East coast of Vancouver Island, British Columbia, Canada, and allowed the identification of sounds from quillback rockfish (Sebastes maliger), copper rockfish (Sebastes caurinus), and lingcod (Ophiodon elongatus), species that had not been documented previously to produce sounds. While each platform developed during this thesis has its own set of advantages and limitations, using them in coordination helps identify fish sounds over different habitats and with various budget and logistical constraints. In an effort to make passive acoustics a more viable way to monitor fish in the wild, this thesis also investigates the use of automatic detection and classification algorithms to efficiently find fish sounds in large passive acoustic datasets. The proposed approach detects acoustic transients using a measure of spectrogram variance and classifies them as “noise” or “fish sounds” using a binary classifier. Five different classification algorithms were trained and evaluated on a dataset of more than 96,000 manually annotated examples of fish sounds and noise from five locations off Vancouver Island. The classification algorithm that performed best (random forest) has an Fscore of 0.84 (Precision = 0.82,Recall = 0.86) on the test dataset. The analysis of 2.5 months of acoustic data collected in a rockfish conservation area off Vancouver Island shows that the proposed detector can be used to efficiently explore large datasets, formulate hypotheses, and help answer practical conservation questions. / Graduate
14

L’automédiatisation, une autre forme de communication sociale / The « automédiatisation », another form of social communication

Amara, Mohamed 30 March 2012 (has links)
L’automédiatisation, comme une autre forme de communication sociale, est une démarche de médiatisation de groupes de parole par l’image vidéo. Dans un contexte de distorsion du lien social (chômage, solitude, repli sur soi…), il s’agit de s’interroger sur la place et le rôle de la caméra dans sa capacité à transformer les sujets individuels et collectifs lorsqu’ils portent un regard sur eux-mêmes et sur la société. Il s’agit aussi de questionner le rapport entre la caméra et le groupe de parole par l’intervention du tiers –médiatiseur (le filmeur). Pour appréhender la façon dont l’outil vidéo façonne, influence la parole des participants d’un groupe, quatre axes de travail se détachent :1) comprendre les relations entre les groupes de parole, la caméra et le filmeur pour participer à un mouvement d’émergence du sujet et à une transformation de la société 2) réfléchir aux capacités de transformation d’un outil, comme la caméra, sur les acteurs, pour sortir du manque de considération ou de l’exclusion3) créer et renforcer les liens entre les participants au sein des groupes et entre les groupes, grâce à l’influence de l’outil vidéo4) partir de l’interdisciplinarité pour appréhender les questions de difficultés de dialogue.A travers ces quatre axes de recherche, le travail de terrain a consisté à comprendre la mise en place d’une médiatisation par des acteurs, confrontés au « diktat » de l’image, car ces mêmes acteurs perçoivent la caméra d'abord comme une occasion de paraître à « l’écran », plus qu’un moyen de débattre des préoccupations quotidiennes ou d’investigation sociologique. C'est pourquoi il faut s'appuyer sur la dynamique du groupe et de ses acteurs pour comprendre en quoi la caméra suscite une communication sociale, et permet aux groupes de parole de réfléchir et de se réfléchir. Mais aussi la question principale : en quoi l’utilisation de la caméra dans le groupe fait-elle évoluer la capacité des participants à "s’auto-analyser" pour aller vers une construction commune, une transformation sociale ? / The automediatisation, as another form of social communication, is an approach of “médiatisation” of speech groups through video image. In a context of distortion of social cohesion (unemployment, loneliness, withdrawal…), we should tackle the question of the place and of the role of video camera in its ability to transform individual and collective subjects when they look at themselves and at society. I also question the relationship between video camera and the speech group through the intervention of a mediating third party (the person who films). In order to apprehend the way the video skill shapes, influences the speech of the participants to a group, four research axis will be followed:- Understanding the relationships between speech groups, the video camera and the person who films, in order to participate to a movement of emergence of the subject and to a transformation of society- Thinking about the capacities of transformation of a skill, like the video camera, on the actors, in order to go out of the miss of consideration or of exclusion.- Creating and enforcing links between participants within groups and between groups, thanks to the influence of the video skill.- Using interdisciplinarity to tackle the subject of difficulties in dialog. Through these four research axis, field work consisted in understanding the implementation of a “médiatisation” by the actors, who were confronted to the “diktat” of image, as these very actors first perceived video camera as an occasion to appear “on screen”, more than a way to discuss their daily concerns or as a skill for sociological investigation. That is why I had to rely on the dynamics of the group and of its actors, so as to understand how video camera creates a social communication, and allows speech groups to think, and to think about themselves. But also the main question: how does the use of video camera in the group allow the development of participant’s ability to analyze themselves, and go towards a common construction, a social transformation?
15

Étude théorique et expérimentale d’une torche plasma triphasée à arcs libres associée à un procédé de gazéification de matière organique / Theoretical and experimental studies of arcs in a three phase plasma torch coupled to a gasification process of organic matter

Rehmet, Christophe 24 September 2013 (has links)
Les torches à arcs plasma sont actuellement utilisées dans de nombreuses applications industrielles. Une technologie plasma triphasée à électrodes en graphite est en cours de développement au Centre PERSEE MINES ParisTech. Cette technologie diffère sensiblement des technologies à courant continu traditionnelles et vise à dépasser certaines limites des systèmes actuels en termes de robustesse, de coûts d'équipement et d'exploitation pour des applications liées à conversion et la valorisation de biomasse et déchets. Dans le but d'améliorer la compréhension des phénomènes physiques instationnaires intervenant dans les décharges triphasées, une étude menée en parallèle sur les plans théorique et expérimental a été conduite en conditions non réactives (azote et gaz de synthèse). Sur un plan expérimental cette étude s'est appuyée sur des analyses réalisées avec une caméra ultra rapide (100 000 images par seconde) et l'analyse des signaux électriques. Sur un plan théorique cette étude a consisté à développer un modèle Magnéto-Hydro-Dynamique (MHD) 3D instationnaire de la zone d'arc dans l'environnement du logiciel Code Saturne® et à effectuer une étude paramétrique basée sur le courant, la fréquence et le débit de gaz plasma. Deux configurations : électrodes coplanaires et parallèles ont été étudiées. Cette étude a permis de mettre en avant l'influence des phénomènes électromagnétiques et hydrodynamiques sur le déplacement de l'arc. Dans le cas coplanaire les jets aux électrodes semblent jouer un rôle prépondérant sur le mouvement des arcs, les transferts de chaleur dans l'espace inter électrode et l'amorçage des arcs. Dans le cas parallèle le mouvement des canaux chauds semble être le paramètre dominant. La confrontation des résultats théoriques et expérimentaux a montré un très bon accord à la fois au niveau du mouvement des arcs et des signaux électriques. / Arc plasma torches are widely used in industrial applications. A 3-phase AC plasma technology with consumable graphite electrodes is under development at PERSEE MINES - ParisTech. This technology noticeably differs from the classical DC plasma torches and aims at overcoming a number of limits of plasma systems in terms of reliability, equipment and operating costs. In order to improve the understanding of the unsteady physical phenomena in such plasma systems, a theoretical and experimental study is conducted under non reactive condition (nitrogen, syngas). Experimental study is based on high speed video camera (100 000 frames per second) and electrical signal analyses. Theoretical analysis is based on 3D unsteady Magneto-Hydro-Dynamic (MHD) model of the arc zone using CFD software Code_Saturne®, by a parametric study based on current, frequency and plasma gas flow rate influence. Two configurations: coplanar and parallel electrodes are studied. These studies highlight the influence of electromagnetic and hydrodynamic phenomena on the arc motion. In coplanar electrode configuration, electrode jets appear to be the dominant parameter on the arc motion, heat transfer and arc ignition. In the parallel electrodes configuration, the motion of the hot channel seems to be the key parameter. Comparison between MHD modeling and experimental results shows a fair correlation, both in accordance with the arc behavior and the electrical waveform.
16

Přídavný paměťový modul pro vysokorychlostní kameru / Extended memory module for the high-speed camera

Trtílek, Jakub January 2017 (has links)
Goal of the diploma thesis is a design of fast memory module and to introduce myself with issues involved in data storage in memory of high speed camera. The work is concerned about two designs adding memory capacity of high speed camera with DDR3 memory modules. For production is selected the more suitable design that is better for commercial purposes. The main objective is to design a schematic with FPGA as a main controller, that will operate data flow from CMOS sensor to superior development board MicroZed. Final design should allow us to sell the high speed camera as a separate unit.
17

Design and Implementation of a Custom Force Pole Assembly for the Measurement of Primate Locomotor Kinetics

Hosseininejad, Justin 03 September 2013 (has links)
No description available.
18

Increasing temporal, structural, and spectral resolution in images using exemplar-based priors

Holloway, Jason 16 September 2013 (has links)
In the past decade, camera manufacturers have offered smaller form factors, smaller pixel sizes (leading to higher resolution images), and faster processing chips to increase the performance of consumer cameras. However, these conventional approaches have failed to capitalize on the spatio-temporal redundancy inherent in images, nor have they adequately provided a solution for finding $3$D point correspondences for cameras sampling different bands of the visible spectrum. In this thesis, we pose the following question---given the repetitious nature of image patches, and appropriate camera architectures, can statistical models be used to increase temporal, structural, or spectral resolution? While many techniques have been suggested to tackle individual aspects of this question, the proposed solutions either require prohibitively expensive hardware modifications and/or require overly simplistic assumptions about the geometry of the scene. We propose a two-stage solution to facilitate image reconstruction; 1) design a linear camera system that optically encodes scene information and 2) recover full scene information using prior models learned from statistics of natural images. By leveraging the tendency of small regions to repeat throughout an image or video, we are able to learn prior models from patches pulled from exemplar images. The quality of this approach will be demonstrated for two application domains, using low-speed video cameras for high-speed video acquisition and multi-spectral fusion using an array of cameras. We also investigate a conventional approach for finding 3D correspondence that enables a generalized assorted array of cameras to operate in multiple modalities, including multi-spectral, high dynamic range, and polarization imaging of dynamic scenes.
19

Analyse comparative de modèles de la qualité des habitats basés sur la densité instantanée et cumulative de poissons

Guéveneux-Julien, Cynthia 05 1900 (has links)
Les écosystèmes aquatiques contiennent environ 25% de la biodiversité globale et sont parmi les plus affectés par l’activité humaine. Cela est entre autres causé par la position de « receveur » des rivières, lacs et océans dans leur bassin versant. Les espèces aquatiques, en eau douce particulièrement, sont ainsi hautement à risque d’être affectées par l’activité humaine. La protection de ces espèces peut inclure la protection et la restauration de leurs habitats. Les modèles de qualité d’habitats (MQH) peuvent être utilisés afin de déterminer quels habitats protéger et restaurer. Les MQH définissent la relation entre un indice de qualité d’habitats (IQH, e.g. densité) et des conditions environnementales. Toutefois, la performance des MQH dépend de l’IQH sélectionné. Ici, notre objectif est de comparer des MQH basés sur deux IQH estimés pour des poissons en rivière : 1) la densité instantanée, échantillonnée en transect par plongée en apnée et 2) la densité cumulative, échantillonnée en point fixe par caméra-vidéo en stéréo. Au total, douze modèles ont été construits et nos analyses indiquent que les MQH basés sur la densité instantanée ont des capacités explicatives significativement supérieures. Les variables environnementales retenues pour expliquer la distribution de chaque espèce sont toutefois différentes. Cela semble être causé en partie par des différences inhérentes à l’échantillonnage (e.g. échelle spatiale). Ces résultats démontrent que la densité instantanée en tant qu’IQH produit des MQH aux capacités explicatives supérieures et que les deux IQH semblent donner des informations complémentaires sur les caractéristiques des habitats à protéger et à restaurer. / Aquatic ecosystems contain approximately 25% of the global biodiversity and are among the most affected by human activity. This may be caused by the position of “receivers” rivers, lakes and oceans have in their watershed. Aquatic species, specially in freshwater, are thus at high risk of being affected by human activity. Assuring the survival of these species may include protecting and restoring their habitats. Habitat quality models (HQM) can be used to determine which habitats to protect and how to restore damaged habitats. HQM are relationships between habitat quality indices (HQI, e.g., density) and environmental conditions prevailing in those habitats. However, how well an HQM performs depends on the chosen HQI it is computed with. For this research, we compared HQM based on two HQI estimated for fish in a river : 1) instantaneous density, sampled by transect snorkeling survey and 2) cumulative density, sampled by fixed stereo-video recording. Analyses of twelve HQM show that, contrary to our hypothesis, HQM based on instantaneous density had higher explanatory capacities. However, environmental conditions selected by both types of HQM to explain a species’ distribution were different. This may in part be explained by inherent differences of the sampling methods (e.g., spatial scale). We conclude that instantaneous density as HQI produces HQM of higher explanatory capacities, yet both HQI may provide complementary information on the characteristics of habitats to protect and restore.
20

A Study of Flow Patterns and Surface Wetting in Gas-Oil-Water Flow

Kee, Kok Eng 24 September 2014 (has links)
No description available.

Page generated in 0.0544 seconds