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Szilagyi, John Michael. "Extreme ultraviolet spectral streak camera." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4578.
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The recent development of extreme ultraviolet (EUV) sources has increased the need for diagnostic tools, and has opened up a previously limited portion of the spectrum. With ultrafast laser systems and spectroscopy moving into shorter timescales and wavelengths, the need for nanosecond scale imaging of EUV is increasing. EUV's high absorption has limited the number of imaging options due to the many atomic resonances in this spectrum. Currently EUV is imaged with photodiodes and X-ray CCDs. However photodiodes are limited in that they can only resolve intensity with respect to time and X-ray CCDs are limited to temporal resolution in the microsecond range. This work shows a novel approach to imaging EUV light over a nanosecond time scale, by using an EUV scintillator to convert EUV to visible light imaged by a conventional streak camera. A laser produced plasma, using a mass-limited tin based target, provided EUV light which was imaged by a grazing incidence flat field spectrometer onto a Ce:YAG scintillator. The EUV spectrum (5 nm-20 nm) provided by the spectrometer is filter by a zirconium filter and then converted by the scintillator to visible light (550 nm) which can then be imaged with conventional optics. Visible light was imaged by an electron image tube based streak camera. The streak camera converts the visible light image to an electron image using a photocathode, and sweeps the image across a recording medium. The streak camera also provides amplification and gating of the image by the means of a micro channel plate, within the image tube, to compensate for low EUV intensities. The system provides 42 ns streaked images of light with a temporal resolution of 440 ps at a repetition rate of 1 Hz. Upon calibration the EUV streak camera developed in this work will be used in future EUV development.ID: 029049655; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.E.E.)--University of Central Florida, 2010.; Includes bibliographical references (p. 73-76).
M.S.E.E.
Masters
School of Electrical Engineering and Computer Science
Engineering and Computer Science
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Walker, David R. "Ultrafast electron-optical visible/X-ray-sensitivity streak and framing cameras." Thesis, University of St Andrews, 1990. http://hdl.handle.net/10023/15033.
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In this thesis the development of ultrafast electron-optical streak and framing cameras having radiation sensitivities ranging from the visible to soft X-ray are discussed. A framing camera incorporating a vacuum demountable image tube with ultraviolet / soft X-ray sensitivity has been demonstrated to be capable of providing multiple, temporally separated, two-dimensional images with picosecond image exposure times under various operating conditions. Experimental evidence has been presented to show that this camera system can provide up to four high quality temporally separated images with an exposure time of 230 ps (FWHM) and inter-frame times of ~1ns under UV illumination. In the two-frame operation with soft X-ray illumination (generated using a laser produced plasma) image exposure times of as short as 100 ps (FWHM) and inter-frame times of 400 ps have been achieved. The dynamic spatial resolution of the camera has been shown to be ~8 lp/mm and ~5 lp/mm for the UV and soft X-ray sensitive devices respectively. A visible-sensitivity electron-optical single-shot streak camera possessing a novel travelling-wave deflection structure has been experimentally evaluated using a mode-locked cw ring dye laser. The limiting temporal resolution for this has been measured to be 300 fs and the merits of the travelling-wave deflection structure have been discussed. The implementation of this type of deflector geometry has also been demonstrated in conjunction with the vacuum demountable framing camera system. Computer aided design techniques have been utilised to further optimise the electron-optical framing tube configuration, and modifications have been proposed to enable shorter frame periods to be obtained while maintaining the dynamic spatial resolution. Results from preliminary evaluations of this design using a vacuum demountable UV-sensitive system are included. A novel streak camera design has also been proposed in which very high electrostatic photocathode extraction fields (up to 12 kV/mm) may be employed without danger of structural damage arising from electrostatic breakdown. This has been achieved by the removal of the usual mesh electrode placed in close proximity to the photocathode. Preliminary evaluations of a vacuum demountable UV-sensitive version of this camera geometry have been achieved which demonstrate a static spatial resolution of 80 lp/mm (when referred to the photocathode).
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Liu, Yueping. "Design and evaluation of ultrafast electron-optical streak and framing cameras." Thesis, University of St Andrews, 1993. http://hdl.handle.net/10023/15036.
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The assessment of the performance of ultrafast electron-optical cameras operating in single-shot, synchroscan streak modes and framing mode has been accomplished and it has provided a better understanding of the limiting factors in the performance of these systems. The characterisation of a Photochron IV streak camera in synchroscan operation has been carried out and this has indicated that apart from the limiting time resolution of the streak tube itself, the amplitude and phase noise in laser sources and electronic circuitry also represent significant limitations to the overall system performance. The simulation of space-charge effects in the single-shot operation of streak cameras has demonstrated that space-charge effects are the key factor that limits the dynamic range. The use of travelling-wave deflection systems has been shown to offer a high deflection sensitivity over a broad frequency range. To achieve femtosecond time resolutions from both synchroscan and single-shot streak cameras, the design of a Photochron V streak tube having optimised electron-optical focusing and deflection systems has been discussed. Analyses have indicated that a limiting time resolution of 250 fs is to be expected. Preliminary tests on an experimental version of a Photochron V tube operating in a synchroscan mode have shown a recorded pulse duration of 3.8 ps. Quantitative theoretical studies of output temporal responses of this tube for different input temporal profiles have indicated that it can reproduce temporal structures of input signals with high fidelity for both synchroscan and single-shot operations in a timescale of around Ips. The analysis of the Picoframe type of framing cameras has led to the refinements of the dynamic performance. For the future development, proposals have been made for the designs of a new streak tube having high dynamic range and a new framing tube having frame times less than 10 ps with potential applications in medical diagnosis.
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Zlatanski, Martin. "Integrated streak camera in standard BiCMOS technology." Strasbourg, 2011. https://publication-theses.unistra.fr/restreint/theses_doctorat/2011/ZLATANSKI_Martin_2011.pdf.
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Les caméras à balayage de fente conventionnelles ont été développées pendant les années 1950 pour l’étude et la mise au point d’explosions nucléaires. Leur fonctionnement est basé sur les principes du tube imageur ou le miroir rotatif, ce qui fait d’elles les instruments de détection optique résolue en temps les plus performants en terme de résolution temporelle. Aujourd’hui, ces technologies sont arrivées à maturité et les performances des caméras à balayage de fente conventionnelles sont proches de leurs limites physiques. Ce document décrit la conception et la caractérisation d’une caméra à balayage de fente intégrée en technologie BiCMOS standard 0. 35 µm. Le prototype est basé sur un vecteur de 64 photodiodes PDIFF–NWELL–PSUB, qui représente directement la fente de la caméra, et une unité d’échantillonnage et de stockage. Le courant photonique délivré par chaque photodiode est converti en tension par un amplificateur transimpédance large bande. La sensibilité et la bande passante de cette structure de capteur dépassent celles des prototypes à architecture matricielle réalisées précédemment. Le balayage temporel est assuré par une ligne à retard contrôlée en tension, commandée par une boucle à verrouillage de délai. Des vitesses de balayage ajustables entre 154 ps/pixel et 1 ns/pixel avec une variation de moins d’un pour cent sur une plage de température de 50° C ont été atteintes. La résolution temporelle de la caméra est de 600 ps à λ = 800 nm et 465 ps à λ = 400 nm. Au moyen de simulations physiques et post-traitement sur la réponse impulsionnelle de la caméra, les réponses en fréquence des photodiodes et de l’amplificateur transimpédance ont été compensées. Par conséquence la résolution temporelle de la caméra atteint 450 ps quelque soit la longueur d’ondeConventional streak-mode imaging devices have been developed in the 1950s to answer the need of photographing atomic explosions. They are based on image converter tube or rotating mirror imaging concepts and feature the highest temporal resolutions achievable with a time-resolved direct optical detection device. Today, conventional streak cameras are still built using the same technologies, which have reached their fundamental limits. The goal of the project in which this work takes part is to propose a solid-state streak-mode imaging device for applications in which a temporal resolution of several hundreds of picoseconds is required. This document presents the design and the characterization of an integrated streak camera in standard 0. 35 µm BiCMOS technology. The prototype is based on a narrow vector of 64 PDIFF–NWELL–PSUB photodiodes, representing the slit of the camera, each one coupled to a 128-deep analog memory through a broadband transimpedance amplifier. Both the sensitivity and the bandwidth of the camera have been improved with respect to the previous pixel array designs operating in photon flux integration mode by means of the single-column photodetecting architecture of the sensor and the direct optical current conversion front-end. The temporal sweep is carried out through a Voltage-Controlled Delay Line driven by a Delay-Locked Loop. A continuously adjustable sweep speed from 154 ps/pixel to 1 ns/pixel has been achieved with less than 1 % variation over a temperature range of 50° C. The measured temporal resolution of the camera is 600 ps at λ = 800 nm and 465 ps at λ = 400 nm. Physical simulations and post-processing of the impulse response of the imager enabled the equalization of the frequency responses of the photodiodes and amplifier. As a result, a temporal resolution of 450 ps has been obtained at both wavelengths, making the speed of the camera independent of the wavelength
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Hartnett, Kathleen A. "Streak camera analysis of dynamic characteristics of current modulated diode laser arrays /." Full text open access at:, 1988. http://content.ohsu.edu/u?/etd,160.
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Malass, Imane. "Design of an integrated streak camera based on a time correlated single photon counting system." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAD001/document.
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Nous présentons une caméra à balayage de fente intégrée basée sur un système de comptage de photon unique résolu en temps (TCSPC-SC) employant l'architecture linéaire « streak » pour surmonter la limitation de l'espace inhérent aux systèmes TCSPC bidimensionnels. Cette solution permet l'intégration de fonctionnalités électroniques complexes dans les pixels sans l'inconvénient d'un faible facteur de remplissage conduisant à une faible efficacité de détection. Le TCSPC-SC se compose de deux blocs principaux: une photodiode à avalanche (SPAD) et un bloc de mesure de temps, les deux blocs sont intégrés en technologie 180 nm CMOS standard. La structure de la SPAD utilisée a été sélectionnée parmi 6 structures différentes après un processus de caractérisation précise et approfondie. Le bloc de mesure du temps se compose d'un TOC hybride capable d'atteindre des résolutions de temps élevées et ajustables avec une large dynamique de mesure grâce à un système de conversion de temps (TOC) hybride qui combine l'approche analogique basée sur un convertisseur de temps vers amplitude(TAC), et les approches numériques utilisant une boucle à verrouillage de retard (DLL) et un compteur numérique. Le TOC hybride a été spécialement conçu pour être utilisé dans un système TCSPC qui intègre une ligne de TOC nécessitant ainsi une conception appropriée pour limiter la consommation d'énergie et la surface d'occupation et parvenir à une architecture flexible et facilement extensible. Suite à la conception et la réalisation de ces deux blocs dans une technologie180 nm CMOS standard, une structure de test de la caméra à balayage de fente (TCSPC-SC) qui englobe 8 unités a été réalisée dans le but final de mettre en œuvre un modèle TCSPC-SC complet et plus largeIn this work we present a TCSPC Streak Camera (TCSPC-SC) that takes advantage of the streak mode imaging ta overcome the space limitation inherent ta 20 TCSPC sensor arrays. This cost-effective solution allows the integration of complex functionalities in the pixel without the inconvenience of low fill factor that leads ta low detection efficiency. The TCSPC~SC consists of two main building blacks: a SPAD and a time measurement black bath integrated in 180 nm Standard CMOS technology. The SPAD was selected among 6 different SPAD structures following a thorough characterization process ta fully determine its performance figures. The time measurement black consists of a hybrid TOC capable of achieving high adjustable time resolutions with large dynamic range owing ta a time conversion scheme that combines traditional Analog Time to Amplitude Converter (TAC), Digital DLL-based and counter-based TOC. Furthermore, thehybrid TOC was especially designed ta be used in a TCSPC system that incorporates an array of TDCs which required a careful design ta limit power consumption and occupation area in order to achieve a flexible and easily scalable architecture. These two building blacks were bath fabricated in a 180 nm standard CMOS technology and employed ta demonstrate a TCSPC Streak Camera(TCSPC-SC) test structure that englobes 8 units in order ta demonstrate the system's operation principle with the final aim of implementing a complete and bigger TCSPC-SC model in the near future
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Anwar, Mamuna [Verfasser], and Markus [Akademischer Betreuer] Drescher. "New Technical Concepts for Velocity Map Imaging in a THz Streak Camera / Mamuna Anwar ; Betreuer: Markus Drescher." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2019. http://d-nb.info/1175584568/34.
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Sparks, Michele Lynn. "Cameron Street Housing: an exercise in urban residential design." Thesis, Virginia Polytechnic Institute and State University, 1995. http://hdl.handle.net/10919/53410.
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In order to make a more attractive and efficient built environment, residential architecture must be incorporated into the fabric of the city. The most successful cities have a mixture of business and residential activities. In most cities, business flourishes in the center, while housing is pushed out to the edges. This causes the city centers to be occupied by day, but abandoned at night. A city with integrated housing becomes a community, a place where people call home. When the city becomes a backyard, it is thought of more carefully and considered to be more important. For this to take place, good urban housing must exist to accommodate the people who will make the city come to life. This urban housing must be attractive enough to make people want to stay for long periods of time and invest in their own improvements. Personalization and pride in a city allow its residents to feel safe and comfortable. When someone respects the place they live in, they respect the environment around it. In other words, good housing is the foundation for a successful community. The objective of this project was to architecturally manifest an urban residential complex that could foster pride and personal identity for the city dweller. The Cameron Street Housing site provided the perfect arena for this objective in Old Town Alexandria, Virginia. The existing surroundings called for a medium density complex that respected the historical styles and showed innovation to accommodate contemporary living. The concept of the project centered around the separation and identity of one's home, the creation of a community within a community, and the use of thresholds to provide layers of space between the public and the private. The forms and materials reflect the surrounding typology without imitating it; the living units conform to modern living without limiting the types of family structures that can inhabit them, and the site provides a sanctuary for its residents while it gives something back to the community. The Cameron Street Housing design stands as an example of what urban housing can do to improve the city around it.Master of Architecture
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Hong, Kirak. "A distributed framework for situation awareness on camera networks." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52263.
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With the proliferation of cameras and advanced video analytics, situation awareness applications that automatically generate actionable knowledge from live camera streams has become an important class of applications in various domains including surveillance, marketing, sports, health care, and traffic monitoring. However, despite the wide range of use cases, developing those applications on large-scale camera networks is extremely challenging because it involves both compute- and data-intensive workloads, has latency-sensitive quality of service requirement, and deals with inherent dynamism (e.g., number of faces detected in a certain area) from the real world. To support developing large-scale situation awareness applications, this dissertation presents a distributed framework that makes two key contributions: 1) it provides a programming model that ensures scalability of applications and 2) it supports low-latency computation and dynamic workload handling through opportunistic event processing and workload distribution over different locations and network hierarchy.
To provide a scalable programming model, two programming abstractions for different levels of application logic are proposed: the first abstraction at the level of real-time target detection and tracking, and the second abstraction for answering spatio-temporal queries at a higher level. The first programming abstraction, Target Container (TC), elevates target as a first-class citizen, allowing domain experts to simply provide handlers for detection, tracking, and comparison of targets. With those handlers, TC runtime system performs priority-aware scheduling to ensure real-time tracking of important targets when resources are not enough to track all targets. The second abstraction, Spatio-temporal Analysis (STA) supports applications to answer queries related to space, time, and occupants using a global state transition table and probabilistic events. To ensure scalability, STA supports bounded communication overhead of state update by providing tuning parameters for the information propagation among distributed workers.
The second part of this work explores two optimization strategies that reduce latency for stream processing and handle dynamic workload. The first strategy, an opportunistic event processing mechanism, performs event processing on predicted locations to provide just-in-time situational information to mobile users. Since location prediction algorithms are inherently inaccurate, the system selects multiple regions using a greedy algorithm to provide highly meaningful information at the given amount of computing resources. The second strategy is to distribute application workload over computing resources that are placed at different locations and various levels of network hierarchy. To support this strategy, the framework provides hierarchical communication primitives and a decentralized resource discovery protocol that allow scalable and highly adaptive load balancing over space and time.
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Meadows, Craig Stuart. "Interaction and Intervention a case study: 1019 Cameron Street, Alexandria, Virginia." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9883.
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It is a favorite canon of preservation architects that soon 95% of work will deal with an existing construct in some manner. Reasons for this include the public's affinity toward old and historic buildings, and the utter lack of undeveloped sites in urban areas. This thesis is directed toward creating a methodology in which to define the intervention and interaction between new to existing. The general attitude toward history and existing buildings is quite divisive. Typically architects demolish existing buildings or they attempt to preserve every detail and facet of a "historical" building. The National Historic Trust, apart of the Department of Interior, provides loose guidelines with which to guide an intervention or to otherwise treat a "historic" edifice. Carlo Scarpa is one architect who has finely honed the ability to interact and intervene.Master of Architecture
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Gierman, Stephen Michael. "Streak camera enhanced quadrupole scan technique for characterizing the temporal dependence of the trace space distribution of a photoinjector electron beam /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9948331.
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Fabritius, T. (Tapio). "Optical method for liquid sorption measurements in paper." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514284045.
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Abstract
This thesis presents an effective optical method for measuring liquid sorption into paper. From the two tested methods, based on a streak-camera and optical coherence tomography (OCT), the last-mentioned proved very promising for investigating dynamical paper-liquid interactions as spatially and temporally dependent processes.
The streak-camera measurements were performed to explore the relationship between paper properties and light migration in dry and refractive index matched paper in general. Based on streak-camera measurements, a novel procedure for determining the average refractive index of cellulose fibre tissue was also presented here. In addition, the streak camera method lent itself to paper porosity determination.
Results of the performed OCT measurements proved that liquids cannot penetrate into paper before filling the pores and pits of the paper surface. As a liquid penetrated into paper, the border between the wetted and dry area could be investigated in the depth direction. The liquid penetration velocity seemed to be slower at the beginning and end of the process. Liquid absorption into paper fibres could be investigated concurrently. For the first time, the location and moment of structural changes in paper could be determined during wetting, and the effect of three different coexistent subprocesses related to paper wetting could be detected. OCT only fell short of detecting the effect of liquid migration along fibres.
Despite the limitations of the utilized method (resolution, probing depth and depth scanning rate), the obtained OCT measurement results are very promising for the development of an effective paper wetting measurement device for industrial applications. Even if this thesis focused on paper wetting, it is reasonable to assert that the presented ideas and obtained results have more general value in terms of explaining liquid penetration into porous structures and offer an alternative method of evaluating that process.
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Bankarusamy, Sudhangathan. "Towards hardware accelerated rectification of high speed stereo image streams." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-37522.
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The process of combining two views of a scene in order to obtain depth information is called stereo vision. When the same is done using a computer it is then called computer stereo vision. Stereo vision is used in robotic application where depth of an object plays a role. Two cameras mounted on a rig is called a stereo camera system. Such a system is able to capture two views and enable robotic application to use the depth information to complete tasks. Anomalies are bound to occur in such a stereo rig, when both the cameras are not parallel to each other. Mounting of the cameras on a rig accurately has physical alignment limitations. Images taken from such a rig has inaccurate depth information and has to be rectified. Therefore rectification is a pre-requisite to computer stereo vision. One such a stereo rig used in this thesis is the GIMME2 stereo camera system. The system has two 10 mega-pixel cameras with on-board FPGA, RAM, processor running Linux operating system, multiple Ethernet ports and an SD card feature amongst others. Stereo rectification on memory constrained hardware is a challenging task as the process itself requires both the images to be stored in the memory. The FPGA on the GIMME2 systems must be used in order to achieve the best possible speed. Programming a system that does not have a display and for used for a specific purpose is called embedded programming. The purpose of this system is distance estimation and working with such a system falls in the Embedded Systems program. This thesis presents a method that makes rectification a step ahead for this particular system. The functionality of the algorithm is shown in MATLAB and using VHDL and is compared to available tools and systems.
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McCoy, John Clinton Ditchkoff Stephen S. "Patterns of stress and suitability of camera surveys for white-tailed deer." Auburn, Ala., 2009. http://hdl.handle.net/10415/2026.
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Aghaei, Maedeh. "Social Signal Processing from Egocentric Photo-Streams." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/650918.
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Wearable photo-cameras offer a hands-free way to record images from the camera- wearer perspective of daily experiences as they are lived, without the necessity to interrupt recording due to the device battery or storage limitations. This stream of images, known as egocentric photo-streams, contains important visual data about the living of the user, where social events among them are of special interest. Social interactions are proven to be a key to longevity and having too few interactions equates the same risk factor as smoking regularly. Considering the importance of the matter, there is no wonder that automatic analysis of social interactions is largely attracting the interest of the scientific community.
Analysis of unconstrained photo-streams however, imposes novel challenges to the social signal processing problem with respect to conventional videos. Due to the free motion of the camera and to its low temporal resolution, abrupt changes in the field of view, in illumination condition and in the target location are highly frequent. Also, since images are acquired under real-world conditions, occlusions occur regularly and appearance of the people undergoes intensive variations from one event to another.
Given a user wearing a photo-camera during a determined period, this thesis, driven by the social signal processing paradigm presents a framework for comprehensive social pattern characterization of the user. In social signal processing, the second step after recording the scene is to track the appearance of multiple people who are involved in the social events. Hence, our proposal begins by introducing a multi-face tracking which holds certain characteristics to deal with challenges imposed by the egocentric photo-streams. Next step forward in social signal processing, is to extract the so-called social signals from the tracked people. In this step, besides the conventionally studied social signals, clothing as a novel social signal is proposed for further studies within the social signal processing. Finally, the last step is social signal analysis, itself. In this thesis, social signal analysis is essentially defined as reaching an understanding of social patterns of a wearable photo-camera user by reviewing captured photos by the worn camera over a period of time. Our proposal for social signal analysis is comprised of first, to detect social interactions of the user where the impact of several social signals on the task is explored. The detected social events are inspected in the second step for categorization into different social meetings. The last step of the framework is to characterize social patterns of the user. Our goal is to quantify the duration, the diversity and the frequency of the user social relations in various social situations. This goal is achieved by the discovery of recurrences of the same people across the whole set of social events related to the user.
Each step of our proposed pipeline is validated over relevant datasets, and the obtained results are reported quantitatively and qualitatively. For each section of the pipeline, a comparison with related state-of-the-art models is provided. A discussion section over the obtained results is also given which is dedicated to highlighting the advantages, shortcomings, and differences of the proposed models, and with regards to the state-of-the-art.Las cámaras portables ofrecen una forma de capturar imágenes de experiencias diarias vividas por el usuario, desde su propia perspectiva y sin la intervención de éste, sin la necesidad de interrumpir la grabación debido a la batería del dispositivo o las limitaciones de almacenamiento. Este conjunto de imágenes, conocidas como secuencias de fotos egocéntricas, contiene datos visuales importantes sobre la vida del usuario, donde entre ellos los eventos sociales son de especial interés. Las interacciones sociales han demostrado ser clave para la longevidad, el tener pocas interacciones equivale al mismo factor de riesgo que fumar regularmente. Teniendo en cuenta la importancia del asunto, no es de extrañar que el análisis automático de las interacciones sociales atraiga en gran medida el interés de la comunidad científica. Sin embargo, el análisis de secuencias de fotos impone nuevos desafíos al problema del procesamiento de las señales sociales con respecto a los videos convencionales. Debido al movimiento libre de la cámara y a su baja resolución temporal, los cambios abruptos en el campo de visión, en la iluminación y en la ubicación del objeto son frecuentes. Además, dado que las imágenes se adquieren en condiciones reales, las oclusiones ocurren con regularidad y la apariencia de las personas varía de un evento a otro. Dado que un individuo usa una cámara fotográfica durante un período determinado, esta tesis, impulsada por el paradigma del procesamiento de señales sociales, presenta un marco para la caracterización integral del patrón social de dicho individuo. En el procesamiento de señales sociales, el segundo paso después de grabar la escena es rastrear la apariencia de varias personas involucradas en los eventos sociales. Por lo tanto, nuestra propuesta comienza con la introducción de un seguimiento de multiples caras que posee ciertas características para hacer frente a los desafíos impuestos por las secuencias de fotos egocéntricas. El siguiente paso en el procesamiento de señales sociales es extraer las señales sociales de las personas bajo análisis. En este paso, adema´s de las señales sociales estudiadas convencionalmente, en esta tesis se propone la vestimenta como una nueva señal social para estudios posteriores dentro del procesamiento de señales sociales. Finalmente, el último paso es el análisis de señales sociales. En esta tesis, el análisis de señales sociales se define esencialmente como la comprensión de los patrones sociales de un usuario de cámara portable, mediante la revisión de fotos capturadas por la cámara llevada durante un período de tiempo. Nuestra propuesta para el análisis de señales sociales se compone de diferentes pasos. En primer lugar, detectar las interacciones sociales del usuario donde se explora el impacto de varias señales sociales en la tarea. Los eventos sociales detectados se inspeccionan en el segundo paso para la categorización en diferentes reuniones sociales. El último paso de la propuesta es caracterizar los patrones sociales del usuario. Nuestro objetivo es cuantificar la duración, la diversidad y la frecuencia de las relaciones sociales del usuario en diversas situaciones sociales. Este objetivo se logra mediante el descubrimiento de apariciones recurrentes de personas en todo el conjunto de eventos sociales relacionados con el usuario. Cada paso de nuestro método propuesto se valida sobre conjuntos de datos relevantes, y los resultados obtenidos se evalúan cuantitativa y cualitativamente. Cada etapa del modelo se compara con los trabajos relacionados más recientes. También, se presenta una sección de discusión sobre los resultados obtenidos, que se centra en resaltar las ventajas, limitaciones y diferencias de los modelos propuestos, y de estos con respecto al estado del arte.
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Dubois, Diane. "Réalisation et caractérisation d'un réacteur plasma de laboratoire pour des études sur la dépollution des gaz d"échappement." Toulouse 3, 2006. http://www.theses.fr/2006TOU30139.
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Cette thèse concerne l’étude expérimentale des décharges couronne positives à la pression atmosphérique générées dans un réacteur de laboratoire de type pointe – plan alimenté en régime de tension continue et pulsée. La nature et les caractéristiques de la décharge couronne, notamment dans son régime de « breakdown streamer », sont étudiées en fonction du régime et de l’amplitude de l’alimentation de tension, du rayon de courbure de la pointe, de la distance inter – électrodes ou encore de la composition du mélange gazeux en faisant varier les proportions de N2, de O2 et de CO2. La dynamique et la morphologie des ondes d’ionisation sont finement étudiées à l’aide de diagnostics d’imagerie rapide (ICCD Streak caméras) et de mesures instantanées de courant et de tension (oscilloscope rapide) sur des échelles de temps de quelques centaines de nanosecondes. Les dimensions du réacteur ont été adaptées à la capacité des modèles à le simuler et les premiers résultats de comparaison des courbes instantanées de courant issues des modèles et de l’expérience sont présentés dans le but ultérieure d’estimer la nature et la densité des radicaux formés durant la phase de décharge d’un réacteur de dépollution par décharge couronneThe present thesis is devoted to the experimental study of atmospheric positive corona discharges generated in a point to plane corona reactor under DC or pulsed high voltage conditions. The corona discharge characteristics, in particular during “breakdown streamer” mode, are studied according to the high voltage supply conditions (DC or pulsed), the point radius curvature, the gap distance or the gas mixture following the variation of the N2, O2 and CO2 concentration. The dynamics and the morphology of the streamers are also studied using fast imaging (ICCD and Streak cameras) and electrical (oscilloscope) diagnostics on time scale lower than hundred of nanosecond. As the corona discharge reactor dimensions are well adapted, some preliminary results show the comparison between experimental and simulated results which allow us in the future to estimate the localization, the density and the nature of the radical species created during the discharge phase of a corona reactor devoted to air pollution control
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Yu, Li. "Localisation Absolue par Mono-caméra d'un Véhicule en Milieu Urbain via l'utilisation de Street View." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM003/document.
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Dans un travail réalisé au Centre de Robotique et à l'Institut VEDECOM, nous nous sommes intéressés aux systèmes robustes de localisation visuelle en milieu urbain pour la voiture autonome. Obtenir une pose exacte à partir d'une mono-caméra est difficile et insuffisant en terme de précision pour la voiture autonome actuelle. Nous nous sommes concentrés sur l'utilisation de Systèmes d'Information Géographiques (SIG) pour concevoir une approche fiable, précise et absolue de localisation en milieu urbain.Le développement de SIG publics nous a apporté un nouvel horizon pour résoudre le problème de la localisation, mais ses informations, telles que les cartes topologiques, sémantiques, métriques, les Street Views, les cartes de profondeur, les cartes cadastrales 3D et les cartes en haute définition, doivent être bien analysées et organisées pour extraire les informations pertinentes pour une voiture autonome. Notre première tâche consistait à concevoir une base de données hors ligne accessible par un robot à partir d'un SIG public dense, à savoir Google Maps, qui a l'avantage d'avoir une couverture mondiale. Nous générons une représentation topométrique compacte de l'environnement urbain en extrayant quatre données utiles du SIG, y compris : les topologies, les géo-coordonnées, les Street Views panoramiques et les cartes de profondeur associées. Dans le même temps, un ensemble de données en ligne a été acquis par une mono-caméra équipée sur les véhicules de VEDECOM. Afin de rendre les Street View sphériques compatibles avec l'imagerie en ligne, une transformation basée sur l'interpolation d'image est introduite pour obtenir des images rectilignes à partir de Street Views.Nous proposons deux méthodes de localisation : l'une est une approche de vision par ordinateur basée sur l'extraction de caractéristiques, l'autre est une méthode d'apprentissage basée sur les réseaux de neurones convolutionnels (convnet). En vision par ordinateur, l'extraction de caractéristiques est un moyen populaire de résoudre le positionnement à partir d'images. Nous tirons parti de Google Maps et utilisons ses données topo-métriques hors ligne pour construire un positionnement grossier à fin, à savoir un processus de reconnaissance de lieu topologique puis une estimation métrique de pose par optimisation de graphe. La méthode a été testée en environnement urbain et démontre à la fois une précision sous-métrique et une robustesse aux changements de point de vue, à l'illumination et à l'occlusion. Aussi, les résultats montrent que les emplacements éloignés de Street Views produisent une erreur significative dans la phase d'estimation métrique. Ainsi, nous proposons de synthétiser des Street Views artificielles pour compenser la densité des Street View originales et améliorer la précision.Cette méthode souffre malheureusement d'un temps de calcul important. Étant donné que le SIG nous offre une base de données géolocalisée à l'échelle mondiale, cela nous motive à régresser des localisations globales directement à partir d'un convnet de bout en bout. La base de données hors ligne précédemment construite est encore insuffisante pour l'apprentissage d'un convnet. Pour compenser cela nous densifions la base d'origine d'un facteur mille et utilisons la méthode d'apprentissage par transfert pour faire converger notre régresseur convnet et avoir une bonne performance. Le régresseur permet également d'obtenir une localisation globale à partir d'une seule image et en temps réel.Les résultats obtenus par ces deux approches nous fournissent des informations sur la comparaison et la relation entre les méthodes basées sur des caractéristiques et celles basées sur le convnet. Après avoir analysé et comparé les performances de localisation des deux méthodes, nous avons également abordé des perspectives pour améliorer la robustesse et la précision de la localisation face au problème de localisation urbaine assistée par SIGIn a work made at Centre de Robotique and Institut VEDECOM, we studied robust visual urban localization systems for self-driving cars. Obtaining an exact pose from a monocular camera is difficult and cannot be applied to the current autonomous cars. We mainly focused on fully leveraging Geographical Information Systems (GIS) to achieve a low-cost, robust, accurate and global urban localization.The development of public GIS's has brought us a new horizon to address the localization problem but their tremendous amount of information, such as topological, semantic, metric maps, Street Views, depth maps, 3D cadastral maps and High Definition maps, has to be well analyzed and organized to extract relevant information for self-driving cars. Our first task was to design a robotic accessible offline database from a dense public GIS, namely Google Maps, which has the advantage to propose a worldwide coverage. We make a compact topometric representation for the dynamic urban environment by extracting four useful data from the GIS, including topologies, geo-coordinates, panoramic Street Views, and associated depth maps. At the same time, an online dataset was acquired with a low-cost camera equipped on VEDECOM vehicles. In order to make spheric Street Views compatible with the online imagery, an image warping and interpolation based transformation is introduced to render rectilinear images from Street Views.We proposed two localization methods: one is a handcrafted-features-based computer vision approach, the other is a convolutional neural network (convnet) based learning technique. In computer vision, extracting handcrafted features is a popular way to solve the image based positioning. We take advantages of the abundant sources from Google Maps and benefit from the topometric offline data structure to build a coarse-to-fine positioning, namely a topological place recognition process and then a metric pose estimation by a graph optimization. The method is tested on an urban environment and demonstrates both sub-meter accuracy and robustness to viewpoint changes, illumination and occlusion. Moreover, we demonstrate that sparse Street View locations produce a significant error in the metric pose estimation phase. Thus our former framework is refined by synthesizing more artificial Street Views to compensate the sparsity of original Street Views and improve the precision.The handcrafted feature based framework requires the image retrieval and graph optimization. It is hard to achieve in a real-time application. Since the GIS offers us a global scale geotagged database, it motivates us to regress global localizations from convnet features in an end-to-end manner. The previously constructed offline database is still insufficient for a convnet training. We hereby augment the originally constructed database by a thousand factor and take advantage of the transfer learning method to make our convnet regressor converge and have a good performance. In our test, the regressor can also give a global localization of an input camera image in real time.The results obtained by the two approaches provide us insights on the comparison and connection between handcrafted feature-based and convnet based methods. After analyzing and comparing the localization performances of both methods, we also talked about some perspectives to improve the localization robustness and precision towards the GIS-aided urban localization problem
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Vasudevan, Devnath. "DETERMINATION OF EFFECTIVE TRAINING METHODS TO LEARN A LAPAROSCOPIC CAMERA NAVIGATION TASK UNDER STRESSFUL ENVIRONMENTS." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2676.
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Stress in surgical environment is generally very high and can result in performance degradation increasing patient risk .Current Training systems for learning minimally invasive surgical skills do not consider the component of stress in their training model. In this study the focus was on developing alternative training models that would allow the learner to effectively perform minimally invasive skill under stress. Two alternate training methods: 1) Training under stress until high performance levels and 2) training until high performance and low cognitive load are achieved were considered for this study. The control group consisted of training under no stress and until high performance levels are achieved. Stressful environments for this study were simulated using physiologic stressors. The effectiveness of the training was evaluated by a comparative analysis of the different performance measures across the groups. We determined that training until automation as the most effective method to perform effectively under stress.
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Achaaban, Mohammed Rachid. "Fluid balance and its hormonal control in the dromedary camel (Camelus dromedarius)." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299860.
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Wong, Timothy. "System Design and Analysis for Creating a 3D Virtual Street Scene for Autonomous Vehicles using Geometric Proxies from a Single Video Camera." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2041.
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Self-driving vehicles use a variety of sensors to understand the environment they are in. In order to do so, they must accurately measure the distances and positions of the objects around them. A common representation of the environment around the vehicle is a 3D point cloud, or a set of 3D data points which represent the positions of objects in the real world relative to the car. However, while accurate and useful, these point clouds require large amounts of memory compared to other representations such as lightweight polygonal meshes. In addition, 3D point clouds can be difficult for a human to visually understand as the data points do not always form a naturally coherent object.
This paper introduces a system to lower the memory consumption needed for the graphical representation of a virtual street environment. At this time, the proposed system takes in as input a single front-facing video. The system uses the video to retrieve still images of a scene which are then segmented to distinguish the different relevant objects, such as cars and stop signs. The system generates a corresponding virtual street scene and these key objects are visualized in the virtual world as low poly, or low resolution, models of the respective objects. This virtual 3D street environment is created to allow a remote operator to visualize the world that the car is traveling through. At this time, the virtual street includes geometric proxies for parallel parked cars in the form of lightweight polygonal meshes. These meshes are predefined, taking up less memory than a point cloud, which can be costly to transmit from the remote vehicle and potentially difficult for a remote human operator to understand. This paper contributes a design and analysis of an initial system for generating and placing these geometric proxies of parked cars in a virtual street environment from one input video. We discuss the limitations and measure the error for this system as well as reflect on future improvements.
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Carvalho, Glaucilene Duarte. "Perdas gasosas de nitrogênio em sistema de produção de arroz irrigado em várzea tropical." Universidade Federal de Goiás, 2015. http://repositorio.bc.ufg.br/tede/handle/tede/7143.
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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
The objective of this study was to characterize the dynamics of nitrous oxide flows and estimate the loss of nitrogen in the form of nitrous oxide and ammonia derived from nitrogen fertilization in rice cultivation in tropical lowland . The experiment was conducted in the experimental area of Embrapa Rice and Beans, at Palmital Farm, in the municipality of Goianira - Goiás, Brazil. The N2O flow soil alternated between positive (output) and negative (inflow) ranging between -83,67 and 470,84 μg N-N2O m-2 h-1; -168,01 to 113, 46 μg N-N2O m-2 h-1 and -103,54 to 290,08 μg N-N2O m-2 h-1 in the 2011/2012 season, off season and 2012/2013, respectively. N losses by volatilization from the use of nitrogen fertilizer, totaled 210 and 203 mg N-NH3 m-2, T1 and T2, respectively. In the off was, on average, 65,08 mg NNH3 m-2 and 2012/2013 amounted to 218,25; 244,80 e 233,78 mg N-NH3 m-2, at T0, T1 and T2, respectively. Actual values for emission factor for NH3-N and N-N2O were below (max. EF = 0.3%) than recommended by the IPCC.
O objetivo deste estudo foi caracterizar a dinâmica dos fluxos de óxido nitroso e estimar a perda de nitrogênio, na forma de óxido nitroso e amônia, derivada da fertilização nitrogenada em cultivo de arroz irrigado em várzea tropical. O experimento foi conduzido na área experimental da Embrapa Arroz e Feijão, na Fazenda Palmital, no município de Goianira- Goiás, Brasil. Os fluxos de N2O do solo alternaram entre positivos (emissão) e negativos (influxo), variando entre -83,67 e 470,84 μg N-N2O m-2 h-1; -168,01 a 113, 46 μg N-N2O m-2 h- 1 e -103,54 a 290,08 μg N-N2O m-2 h-1 na safra 2011/2012, entressafra e 2012/2013, respectivamente. As perdas de N por volatilização de amônia decorrentes da utilização de fertilizante nitrogenado, totalizaram 210 mg m-2 e 203 mg m-2 de N-NH3, em T1 e T2, respectivamente. Na entressafra foi, em média, 65,08 mg m-2 de N-NH3 e 2012/2013 totalizaram 218,25 mg m-2, 244,80 mg m-2 e 233,78 de N-NH3, em T0, T1 e T2, respectivamente. Os valores encontrados de fator de emissão para N-NH3 e N-N2O foram abaixo (max. FE = 0,3 %) do preconizado pelo IPCC.
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Shakya, Mahendra Man. "Generation of intense high harmonics : i) to test and improve resolution of accumulative x-ray streak camera ii) to study the effects of carrier envelope phase on XUV super continuum generation by polarization gating." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/408.
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Erasmus, Nicolas. "Ultrafast structural dynamics in 4Hb-TaSe2 observed by femtosecond electron diffraction." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79934.
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Thesis (PhD)--Stellenbosch University, 2013.ENGLISH ABSTRACT: In this thesis the structural dynamics, upon photo-excitation, of the charge-densitywave (CDW) material 4Hb-TaSe2 is investigated on the time-scale of atomic motion and simultaneously on the spatial-scale of atomic dimensions. CDW materials have been of interest since their discovery in the 1970’s because of their remarkable non-linear and anisotropic electrical properties, gigantic dielectric constants, unusual elastic properties and rich dynamical behaviour. Some of these exotic properties were extensively investigated in thermal equilibrium soon after their discovery but only recently have ultrafast techniques like femtosecond spectroscopy become available to study their out-of-equilibrium behaviour on the time-scale of atomic motion. By studying their behaviour on this time-scale a more in-depth understanding of their macroscopic properties can be gained. However, to do investigations on the atomic time-scale and simultaneously directly observe the evolution of the atomic arrangements is another challenge. One approach is through the previously mentioned technique of femtosecond pump-probe spectroscopy but converting the usual ultrashort optical probing source to an ultrashort electron or x-ray source that can diffract off the sample and reveal structural detail on the atomic level. Here, the femto-to-picosecond out-of-equilibrium behaviour upon photo-excitation in 4Hb-TaSe2 is investigated using an ultrashort electron probe source. Two variations of using an electron probe source are used: conventional scanning Femtosecond Electron Diffraction (FED) and a new approach namely Femtosecond Streaked Electron Diffraction (FSED). The more established FED technique, based on femtosecond pumpprobe spectroscopy, is used as the major investigating tool while the FSED technique, based on ultrafast streak camera technology, is an attempt at broadening the scope of available techniques to study structural dynamics in crystalline material on the subpicosecond time-scale. With these two techniques, the structural dynamics during the phase transition from the commensurate- to incommensurate-CDW phase in 4Hb-TaSe2 is observed through diffraction patterns with a temporal resolution of under 500 fs. The study reveals strong coupling between the electronic and lattice systems of the material and several time-constants of under and above a picosecond are extracted from the data. Using these time-constants, the structural evolution during the phase transition is better understood and with the newly gained knowledge, a model of all the processes involved after photo-excitation is proposed.
AFRIKAANSE OPSOMMING: In hierdie tesis word die strukturele dinamika van die lading-digtheid-golf (LDG) materiaal 4Hb-TaSe2 ondersoek op die tydskaal van atomiese bewegings en gelyktydig op die ruimtelikeskaal van atomiese dimensies. LDG materie is al van belang sedert hul ontdekking in die 1970’s as gevolg van hul merkwaardige nie-lineêre en anisotrope elektriese eienskappe, reuse diëlektriese konstantes, ongewone elastiese eienskappe en ryk dinamiese gedrag. Sommige van hierdie eksotiese eienskappe is omvattend ondersoek in termiese ewewig kort na hul ontdekking, maar eers onlangs is dit moontlik deur middle van ultravinnige tegnieke soos femtosekonde spektroskopie om hulle uit-ewewigs gedrag te bestudeer op die tydskaal van atomiese beweging. Deur die gedrag op hierdie tydskaal te bestudeer kan ’n meer insiggewende begrip van hul makroskopiese eienskappe verkry word. Om ondersoeke in te stel op die atomiese tydskaal en gelyktydig direk die evolusie van die atoom posisie te waarneem is egter ’n moeilike taak. Een benadering is deur middle van femtosekonde “pump-probe” spektroskopie maar dan die gewone optiese “probe” puls om te skakel na ’n electron of x-straal puls wat van die materiaal kan diffrak en dus strukturele inligting op die atomiese vlak kan onthul. Hier word die femto-tot-pico sekonde uit-ewewig gedrag in 4Hb-TaSe2 ondersoek met behulp van elektron pulse. Twee variasies van die gebruik van ’n elektron bron word gebruik: konvensionele “Femtosecond Electron Diffraction” (FED) en ’n nuwe benadering, naamlik, “Femtosecond Streaked Electron Diffraction” (FSED). Die meer gevestigde FED tegniek, wat gebaseer is op femtosekonde “pump-probe” spektroskopie, word gebruik as die hoof ondersoek metode terwyl die FSED tegniek, wat gebaseer is op die ultra vinnige “streak camera” tegnologie, ’n poging is om beskikbare tegnieke uit te brei wat gebruik kan word om strukturele dinamika in materie te bestudeer op die sub-picosekonde tydskaal. Met behulp van hierdie twee tegnieke, word die strukturele dinamika tydens die fase oorgang van die ooreenkomstige tot nie-ooreenkomstige LDG fase in 4Hb-TaSe2 deur diffraksie patrone met ’n tydresolusie van minder as 500 fs waargeneem. Die studie toon ’n sterk korrelasie tussen die elektroniese sisteem en kristalrooster. Verskeie tydkonstantes van onder en bo ’n picosekonde kon ook uit die data onttrek word en gebruik word om die strukturele veranderinge beter te verstaan. Hierdie nuwe kennis het ons in staat gestel om ’n model van al die betrokke prosesse voor te stel.
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Kassier, Gunther Horst. "Ultrafast electron diffraction : source development, diffractometer design and pulse characterisation." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5359.
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Thesis (PhD (Physics))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Ultrafast Electron Diffraction (UED) is a rapidly maturing field which allows investigation of the evolution of atomic arrangement in solids on timescales comparable to the vibrational period of their constituent atoms (~10-13 s). The technique is an amalgamation of conventional high energy electron diffraction methods and pump-probe spectroscopy with femtosecond (1 fs = 10-15 s) laser pulses. Ultrafast pulsed electron sources generally suffer from limitations on the attainable electron number per pulse (brightness) due to Coulomb repulsion among the electrons. In this dissertation, the design and construction of a compact UED source capable of delivering sub-300 fs electron pulses suitable for diffraction experiments and containing about 5000 electrons per shot is described. The setup has been characterised by measurement of the transverse beam size and angular spread, and through recording and analyzing an electron diffraction pattern from a titanium foil. Measurement of the temporal duration of fs electron pulses is not trivial, and a specialised compact streak camera operating in accumulation mode has been developed as part of this study. A sub-200 fs temporal resolution has been achieved, and the dependence of temporal duration on electron number per pulse was investigated for the current UED source. The observed trends correlate well with detailed electron bunch simulations. In order to investigate ultrafast processes on samples that cannot be probed repeatedly, it becomes necessary to significantly increase the brightness of current state of the art compact sources such as the one constructed in the present study. UED sources employing electron pulse compression techniques offer this possibility. Traditional pulse compression schemes based on RF cavities, while simple in principle, pose significant technical challenges in their realisation. The current thesis describes two novel UED pulse compression methods developed by the author: achromatic reflectron compression and pulsed cavity compression. Both concepts are expected to be easier to realise than conventional RF compression. Detailed simulations predict that such sources can attain a brightness improvement of more than one order of magnitude over compact sources that do not employ compression techniques. In addition, such sources show much promise for the attainment of pulse durations in the sub-100 fs range.
AFRIKAANSE OPSOMMING: Ultra vinnige elektron diffraksie is ‘n meettegniek wat tans in die proses is om vinnige ontwikkeling te ondergaan. Die tegniek het ten doel om strukturele omsettingsprosesse op ‘n lengteskaal van atoombindings en ‘n tydskaal van die vibrasie periode van atome in materie, ongeveer 10-13 s, te ondersoek. Dit word bewerkstellig deur die spasieresolusievermoë van gewone hoë energie elektron diffraksie met die tydresolusievermoë van femtosekonde (1 fs = 10-15 s) laserspektroskopie te kombineer. Die aantal elektrone per puls (intensiteit) van ultravinnige gepulsde elektronbronne word beperk deur die Coulomb afstootingskragte tussen die elektrone. Hierdie dissertasie beskryf die ontwerp en konstruksie van ‘n kompakte ultravinnige elektron bron. Die elektronpulse wat geproduseer word bevat tot 5000 elektrone per puls met ‘n tyd durasie van minder as 300 fs, en is geskik vir diffraksie eksperimente. Die aparaat is gekarakteriseer deur die volgende metings: elektronpulsdiameter, straaldivergensie, en ‘n titaan foelie se statiese diffraksie patroon. Dit is nie triviaal om die durasie van femtosekonde elektronpulse te meet nie, en n spesiale kompakte akkumulerende “streak camera” is vir die doeleindes van hierdie projek onwikkel. Die tydresolusie van hierdie “streak camera” is beter as 200 fs, en die afhanklikheid van die pulsdurasie wat deur die ultravinnige elektron bron geproduseer word as n funksie van die elektrongetal per puls is met behulp van hierdie toestel bepaal. Die resultate klop redelik goed met gedetaileerde simulasies van die elektron puls dinamika. Die karakterisasie van monsters wat nie herhaaldelik gemeet kan word nie vereis verkieslik ‘n nog hoër pulsintensiteit as wat met huidige bronne bereik kan word. ‘N verdere doelstelling is dus om ultravinnige elektron bronne te ontwikkel wat pulse met meer elektrone per puls kan genereer. Dit kan bewerkstellig word deur bronne wat van elektron puls kompressie tegnieke gebruik maak. Die tradisionele manier waarop dít gedoen word is deur middel van n kontinu gedrewe radio frekwensie holte. Hierdie metode gaan egter gepaard met aanmerklik hoë tegniese uitdagings. Om hierdie rede het die outeur twee alternatiewe puls kompressie konsepte ontwikkel: akromatiese reflektron kompressie and gepulsde holte kompressie. Albei konsepte sal waarskeinlik makliker wees om te realiseer as die tradisionele radio frekwensie kompressie, en is deur middel van gedetaileerde simulasies geverifiseer. Hierdie simulasies voorspel dat die intensiteit van genoemde bronne met ten minste n grooteorde meer kan wees as wat tans met kompakte ultravinnige elektron bronne moontlik is. Verder blyk dit dat sulke bronne n pulsdurasie van minder as 100 fs kan bereik.
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Saarela, J. (Juha). "Photon migration in pulp and paper." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514275845.
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Abstract
The thesis clearly demonstrates that photon migration measurements allow characterization of pulp and paper properties, especially the fines and filler content of pulp, and the basis weight, thickness and porosity of paper.
Pulp and paper are materials with a worldwide significance. Their properties strongly depend on the manufacturing process used. For efficient process control, the employed monitoring and measuring has to be fast. Therefore it is worthwhile to try to develop new approaches and techniques for such measurements. Recent advancements in optics offer new possibilities for such development.
If two samples have different optical properties their photon migration distributions are different. The measurement of a photon migration distribution allows some features between two optically slightly dissimilar samples to be distinguished. Some simple measurements, which only yielded the photons' average time of flight, were made with an oscilloscope and a time-of-flight lidar. More precise measurements yielding photon pathway distribution or some selected characteristics like light pulse rise time, broadening, or fall time were measured with a streak camera. Two methods to assess photon path length distribution were introduced: particle determination with simulation, and streak camera with deconvolution.
The basic properties for pulp are consistency and fines content and for paper the basic properties are thickness, basis weight and porosity. The influence on photon migration caused by changes in these basic properties was determined.
As pulp and paper are rarely very basic, an additional property was demonstrated for both materials. For pulp it was the content of filler talc, and for paper it was the use of beaten pulp as a raw material. These additional properties were also distinguishable.
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Torche, Fayçal. "Contribution à l'étude des électrons solvatés dans l’eau et les alcools et des processus radiolytiques dans les carbonates organiques par radiolyse impulsionnelle picoseconde." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112132/document.
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Le travail présenté dans cette thèse, s’inscrit dans le domaine d'étude de l'interaction des rayonnements ionisants avec les liquides polaires. Bénéficiant de l’accélérateur d'électrons picoseconde ELYSE, les études ont été menées en utilisant les techniques de la radiolyse impulsionnelle associées à la spectrophotométrie d’absorption résolue en temps dans le domaine de la picoseconde. Ce travail est réparti sur deux chapitres distincts. Le premier aborde l’étude la variation temporelle du rendement radiolytique de l’électron solvaté dans l'eau et les alcools simples. Grâce au système de détection original monté sur l’accélérateur ELYSE, composé d’une lampe flash spécialement conçue pour cette détection et d’une streak-camera utilisée pour la première fois en spectroscopie d’absorption, il a été possible d'enregistrer la totalité du déclin du rendement radiolytique de l’électron solvaté d’une façon continue dans un intervalle de temps allant de la dizaine de picoseconde à quelques centaines de nanoseconde. La capture de l’électron solvaté par le méthylviologène, a été mise à profit pour réévaluer le coefficient d’extinction molaire du spectre d'absorption de l’électron solvaté dans l’eau et l’éthanol à partir des points isobestiques qui apparaissent à l'intersection des spectres d'absorption de l’électron solvaté qui disparaît et du méthylviologène qui se forme au cours de la réaction.Le deuxième chapitre est consacré à l’étude des carbonates organiques liquides, tels que le diméthyle carbonate (DMC), le diéthyle carbonate (DEC) et le propylène carbonate (PC). Cette famille de carbonate qui n’a jamais été étudiée auparavant par radiolyse pulsée, entre dans la composition des électrolytes des batteries notamment au lithium. Les études ont été focalisées sur le PC au vu de ces caractéristiques physico-chimiques, notamment sa constante diélectrique très élevée (64) et son très fort moment dipolaire de 4,9 D. Les premiers résultats ont été obtenus d’abord sur des solutions aqueuses contenant du propylène carbonate afin d'observer les réactions de réduction et d'oxydation du PC par les espèces radiolytiques de l'eau (électron solvaté et radicaux OH). Puis après l’identification (spectrale et cinétique) de l’espèce formée par interaction avec le radical OH comme étant le radical PC• résultant de l'abstraction d'un H de la molécule de PC et l’espèce formée par interaction avec l’électron aqueux comme étant l'anion PC-, d’autres mesures ont été effectuées dans le liquide pur ainsi qu’en présence de certains intercepteurs d’électrons (biphényle, anthracène, naphtalène). Elles ont permis d'accéder au rendement radiolytique de PC- ainsi qu'à l'évaluation de son potentiel redox. Les premiers résultats sur le DEC et le DMC sont aussi exposés dans cette partie, portant dans un premier lieu sur le solvant pur et puis en présence de biphényleThis work is part of the study area of the interaction of radiation with polar liquids. Using the picosecond electron accelerator ELYSE, studies were conducted using the techniques of pulse radiolysis combined with absorption spectrophotometry Time-resolved in the field of a picosecond.This work is divided into two separate chapters. The first study addresses the temporal variation of the radiolytic yield of solvated electron in water and simple alcohols. Due to original detection system mounted on the accelerator ELYSE, composed of a flash lamp specifically designed for the detection and a streak-camera used for the first time in absorption spectroscopy, it was possible to record the time-dependent radiolytic yields of the solvated electron from ten picoseconds to a few hundred nanoseconds. The scavenging of the electron solvated by methyl viologen, was utilized to reevaluate the molar extinction coefficient of the absorption spectrum of solvated electron in water and ethanol from isobestic points which corresponds to the intersection of the absorption spectra of solvated electron which disappears and methyl viologen which is formed during the reaction.The second chapter is devoted to the study of liquid organic carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC) and propylene carbonate (PC). This family of carbonate wich compose the electrolytes lithium batteries, has never been investigated by pulse radiolysis. The studies were focused on the PC in the light of these physicochemical characteristics, including its very high dielectric constant (64) and its strong dipole moment of 4.9 D. The first results were obtained on aqueous solutions containing propylene carbonate to observe the reactions of reduction and oxidation of PC by radiolytic species of water (solvated electron and OH radicals). Then, after the identification (spectral and kinetic) of the species formed by interaction with the OH radical as the PC• radical resulting from the abstraction of a H from the molecule of PC and the species formed by the interaction with electron as the anion aqueous PC-, other measurements were made in the pure liquid and in the presence of some electron interceptors (biphenyl, anthracene, naphthalene). They give access to the radiolytic yield of PC- and the evaluation of its redox potential. The first results of the DEC and the DMC are also outlined in this section, the pure solvent and then in the presence of biphenyl
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Mangus, Devin. "Developing thermal infrared imaging systems for monitoring spatial crop temperatures for precision agriculture applications." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/35241.
Full textAbstract:
Master of ScienceDepartment of Biological & Agricultural Engineering
Ajay Sharda
Precise water application conserves resources, reduces costs, and optimizes plant performance and quality. Existing irrigation scheduling utilizes single, localized measurements that do not account for spatial crop water need; but, quick, single-point sensors are impractical for measuring discrete variations across large coverage areas. Thermography is an alternate approach for measuring spatial temperatures to quantify crop health. However, agricultural studies using thermography are limited due to previous camera expense, unfamiliar use and calibration, software for image acquisition and high-throughput processing specifically designed for thermal imagery mapping and monitoring spatial crop water need. Recent advancements in thermal detectors and sensing platforms have allowed uncooled thermal infrared (TIR) cameras to become suited for crop sensing. Therefore, a small, lightweight thermal infrared imaging system (TIRIS) was developed capable of radiometric temperature measurements. One-time (OT) and real-time (RT) radiometric calibrations methods were developed and validated for repeatable, temperature measurements while compensating for strict environmental conditions within a climate chamber. The Tamarisk® 320 and 640 analog output yielded a measurement accuracy of ±0.82°C or 0.62ºC with OT and RT radiometric calibration, respectively. The Tamarisk® 320 digital output yielded a measurement accuracy of ±0.43 or 0.29ºC with OT and RT radiometric calibration, respectively. Similarly, the FLIR® Tau 2 analog output yielded a measurement accuracy of ±0.87 or 0.63ºC with OT and RT radiometric calibration, respectively. A TIRIS was then built for high-throughput image capture, correction, and processing and RT environmental compensation for monitoring crop water stress within a greenhouse and temperature mapping aboard a small unmanned aerial systems (sUAS). The greenhouse TIRIS was evaluated by extracting plant temperatures for monitoring full-season crop water stress index (CWSI) measurements. Canopy temperatures demonstrated that CWSI explained 82% of the soil moisture variation. Similarly, validation aboard a sUAS provided radiometric thermal maps with a ±1.38°C (α=0.05) measurement accuracy. Due to the TIR cameras’ performance aboard sUAS and greenhouse platforms, a TIRIS provides unparalleled spatial coverage and measurement accuracy capable of monitoring subtle crop stress indicators. Further studies need to be conducted to produce spatial crop water stress maps at scales necessary for variable rate irrigation systems.
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Brule, David Melo Van Den. "Territorialização como apropriação do espaço público pelos camelôs nas romarias de Juazeiro do Norte-CE." Universidade Federal da Paraíba, 2011. http://tede.biblioteca.ufpb.br:8080/handle/tede/5800.
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Previous issue date: 2011-08-30Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This dissertation is meant to examine the use of public space by street vendors - most notably by the stand living - in the territorial dynamics in the religious/commercial center of city of Juazeiro do Norte in times of pilgrimage. Juazeiro do Norte is located in Cariri, south of Ceará, with an estimated population of 249,939 inhabitants, according to IBGE (2010). Every year, approximately two million faithful get to the city founded by Father Cicero Romao Batista. In this work, the process of deterritorialization and reterritorialization of stand residents who came to occupy the newly opened Support Center for Pilgrims, near Matriz Church, a major focus of pilgrimages. To analyze the use of squares, streets and sidewalks by street vendors, it was made use of the concept of territory on Souza and Haesbeart´s view, adding that the studies that deal with the issue of medium-sized cities, downtown and central to investigate the emergence of a new central role in increasing the flow of budget, infrastructure and range of services offered in this city, the procedures used were: a) interviews, b) passive observation of the lives of street vendors and through questionnaires, and c ) record in photographs and analyzes them. This research also contributes in that it gives visibility to a little-seen daily, one in which the unregistered worker, restricted from rights seek a decent life through work, hoping for better days.
A presente dissertação tem como principal objetivo analisar o uso do espaço público pelos camelôs mais especificamente pelas barraqueiras moradoras na dinâmica territorial do centro religioso/comercial da cidade de Juazeiro do Norte, em momentos de romarias. Juazeiro do Norte está localizada na região do Cariri, sul do Estado do Ceará, com uma população estimada em 249.939 habitantes, segundo IBGE (2010). Todos os anos, aproximadamente dois milhões de fiéis chegam à cidade fundada pelo Padre Cícero Romão Batista. Neste trabalho, investigou-se o processo de desterritorialização e reterritorialização das barraqueiras moradoras que passaram a ocupar o recém inaugurado Centro de Apoio aos Romeiros, próximo à Igreja da Matriz, um dos principais focos das romarias. Para analisar o uso de praças, ruas e calçadas, pelos camelôs, fez-se uso do conceito de território na visão de Souza e Haesbeart, somando-se a isto estudos que versam sobre o tema das cidades médias, centro e centralidade, para investigar o surgimento de uma nova centralidade em função do aumento do fluxo de orçamento, infraestrutura e variedade de serviços ofertados nesta cidade, os procedimentos metodológicos utilizados foram: a) entrevistas; b) observação passiva do cotidiano dos camelôs e através de aplicação de questionários; e c) registro em fotografias e análises das mesmas. Esta pesquisa contribui também na medida em que dá visibilidade a um cotidiano pouco visto, aquele em que o trabalhador sem carteira assinada, e restrito de direitos busca uma vida digna através do trabalho, na esperança por dias melhores.
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White, Jonathan Charles. "HIGH-FRAME-RATE OIL FILM INTERFEROMETRY." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/572.
Full textAbstract:
High-Frame-Rate Oil Film Interferometry
Jonathan Charles White
This thesis presents the design and implementation of a high-frame-rate oil film interferometry technique (HOFI) used to directly measure skin friction in time dependent flows. Experiments were performed to determine the ability of a high-speed camera to capture oil film interferometry images. HOFI was found to be able to capture these interferometry images at frequencies up to 105 Hz. Steady laminar and turbulent flows were tested. Transient flows tested consisted of a wind tunnel ramping up in velocity and a laminar boundary layer which was intermittently tripped to turbulence by puffing air out of a pressure tap. Flow speeds ranged from 0 to 108 ft/sec and 10 and 50 cSt Dow Corning 200 dimethylpolysiloxane silicone oil was used. The skin friction was determined from the rate of change of the height of the oil film using lubrication theory. The height of the oil film was determined from the high speed camera interferogram images using a MATLAB script which determined fringe spacing by fitting a four-parameter sine wave to the intensity levels in each image. The MATLAB script was able to determine the height of the oil film for thousands of interferogram images in only a few minutes with sub-pixel error in fringe spacing. The skin friction was calculated using the oil film height history allowing for the direct measurement of skin friction in time dependent flows.
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Kopper, Moisés. "De camelôs a lojistas : etnografia da transição do mercado de rua para um shopping popular em Porto Alegre-RS." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/54101.
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Esta dissertação parte das tensões envolvidas no processo de remoção do mercado de rua do centro de Porto Alegre/RS e sua realocação para um shopping popular. O “camelódromo”, como ficou conhecido o edifício que abriga mais de 800 lojas – de aproximadamente 4m² –, foi realizado em tempo recorde graças a uma Parceria Público Privada (PPP), a primeira do gênero em Porto Alegre e uma das pioneiras no Brasil. A dissertação privilegia a abordagem etnográfica, baseada numa inserção de campo de mais de três anos, o que permitiu captar o processo em perspectiva diacrônica. A observação participante – acrescida de outras técnicas, como entrevistas em profundidade e surveys – teve como ponto de partida um dos principais grupos de camelôs envolvidos na transição. Este grupo, inicialmente otimista em relação à transição, foi preterido na disputa pelos melhores espaços no camelódromo e reagiu com uma série de mobilizações. Foram acionadas diversas instituições políticas, tais como a Câmara Municipal, o Ministério Público, a Prefeitura, e o Orçamento Participativo, entre outras. Esta estratégia mostrou-se ineficiente e culminou com o despejo de vários lojistas inadimplentes – entre eles o principal líder do grupo –, e a dissipação da mobilização coletiva. No entanto, as tensões não cessaram, pois a transição das ruas para o camelódromo foi acompanhada de perto pela empresa, que exigiu uma mudança na sensibilidade comercial, a partir de uma política de pedagogização visando forjar um novo perfil de comerciante, indispensável ao sucesso econômico do empreendimento. Novas modalidades de conflitos emergiram dessa estratégia, pois nem todos os camelôs se reconverteram no protótipo de lojista idealizado pela PPP. As tensões em torno desse processo criaram um cenário propício para uma investigação que se preocupa em reconstituir etnograficamente os nexos entre a economia e a política, o objetivo e o subjetivo, o micro e o macro, a cidade e os cidadãos, a diversidade de agentes e de agências que caracterizam uma dada configuração social e cultural.This dissertation starts with the tensions involved in the removal of the street market in downtown Porto Alegre/RS and its relocation to a popular mall. The “camelódromo”, as the building – which houses more than 800 stands of roughly four square meters – became known, was accomplished in record time thanks to a Public-Private Partnership (PPP), the first of its kind in Porto Alegre and one of the first in Brazil. The dissertation relies on the ethnographic approach, based on a field insertion of more than three years, which allowed capturing the process in a diachronic perspective. The participant observation – plus other techniques such as interviews and surveys – had as its starting point a major group of vendors involved in the transition. This group, initially optimistic about the transition, was passed over in the race for the best spaces in the camelódromo, and reacted with a series of mobilizations. Several political institutions were called upon, such as the City Council, the Prosecutor, the City Hall, and the Participatory Budget, among others. This strategy proved itself ineffective, and resulted in the eviction of several defaulting tenants – including the main leader of the group – and the dissipation of the collective mobilization. However, the tensions didn’t cease, as the transition from the streets to the camelódromo was closely monitored by the company, which required a change in the commercial sensitivity, based on a pedagogization policy aimed to forge a new trader profile, essential to the economic success of the enterprise. New modalities of conflict arose from this strategy, because not all vendors reconverted themselves into the prototype designed by the PPP. The tensions around this process created a favorable environment for a research that tries to retrace ethnographically the connections between economics and politics, the objective and the subjective, the micro and the macro, the city and the citizens, the diversity of agents and agencies that characterize a given social and cultural setting.
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Durães, Bruno José Rodrigues. ""Camelô de tecnologia" ou "Camelô Global" = novas formas de expansão do capital na rua." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/280165.
Full textAbstract:
Orientador: Angela Maria Carneiro AraújoTese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas
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Resumo: A presente tese trata dos trabalhadores de rua que ofertam produtos tecnológicos (máquinas digitais, games, pen drivers etc.) no camelódromo da rua Uruguaiana no Rio de Janeiro. Pretendeu-se responder a seguinte questão: será o camelô de tecnologia uma forma diferenciada de relação de trabalho informal de rua, na qual a lógica predominante é a do negócio (do lucro), da empresa (do capital) e não a do trabalhador (ligado a sobrevivência), na qual evidencia-se uma separação entre capital (donos dos meios e do dinheiro) e trabalho (força de trabalho contratada)?Nessa linha, serão atividades que agora passam a servir como veias de expansão do capital? Tivemos como objetivo geral desta pesquisa: explorar essa nova diferenciação presente nas formas de trabalho de rua na sociedade brasileira atual, ou seja, compreender o que é essa nova (re)configuração da rua. Esse fenômeno evidencia um tipo de atividade que sofre interferências diretas do mundo formal, reconfigurando-se e assumindo feições empresariais. Foram aplicados 42 questionários com estes camelôs
Abstract: This thesis deals with street workers that offer technological products (digital cameras, games, flash drivers etc.) in camelódromo of the Uruguayana in Rio de Janeiro. It was intended to answer the following question: Is the peddler of a differentiated form of technology for informal street work, which is the predominant business (profit), business (the capital) and not the employee (linked to survival), which is evident separation between capital (owners of the means and money) and work (labor contractor)? this line will be activities that now serve as the veins of capital expansion? Our aim of this research: to explore the new forms of differentiation in this street work in the current Brazilian society, ie, understand what is this new (re) configuration of the street. This phenomenon reflects a kind of activity that suffers direct interference of the formal world, reshaping itself and assuming business features. 42 questionnaires were applied to these vendors
Doutorado
Ciencias Sociais
Doutor em Ciências Sociais
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Wlotzko, Vincent. "Conception et réalisation d'une caméra à balayage de fente à résolution temporelle picoseconde et à haut taux de répétition." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAD009/document.
Full textAbstract:
Les caméras à balayage de fente sont les instruments de détection directe de la lumière les plus précis en termes de résolution temporelle. Ces instruments sont capables de capturer des évènements de l’ordre de la picoseconde à un taux de répétition d’une centaine de mégahertz. Cependant, les performances de la caméra sont limitées par de nombreux phénomènes propres au fonctionnement de cette dernière mais aussi au système l’implémentant. Plusieurs effets dégradant la résolution temporelle sont étudiés. Le premier axe exploré concerne la synchronisation de la caméra avec l’évènement lumineux capturé. Cette investigation débouche sur le développement d’un discriminateur à fraction constante permettant de déclencher la caméra avec un jitter inférieur à 200 fs RMS. Une autre étude présente l’impact qu’ont le bruit d’amplitude et le bruit de phase des lasers usuellement utilisés avec la caméra sur sa synchronisation. Enfin une analyse des phénomènes intrinsèques à la photocathode de la caméra permet d’évaluer la variation du temps de transit des électrons dans celle-ciStreak cameras are the direct light detection instruments that are the best in terms of temporal resolution. Those instruments can capture picosecond light events at a hundred megahertz repetition rate. However their characteristics are limited by various phenomena specific to the camera and the implementing system. Several effects that affect the temporal resolution are studied. The first examined line deals with the synchronization of the camera with the studied light event. This inquiry led to the design of a constant fraction discriminator allowing a sub 200 fs RMS jitter triggering. Another study shows the impact of the usually used laser amplitude noise and phase noise on the system’s synchronization. Finally, an analysis of the camera’s photocathode intrinsic phenomena allows estimating the transit time variation of the electrons within the vacuum tube
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Zhengyu, Wang, and Yousuf Al-Shorji. "Fisheye live streaming : A study of the dewarping function and the performance of the streaming." Thesis, KTH, Hälsoinformatik och logistik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-236503.
Full textAbstract:
Provision of live streaming of video from fisheye camera is a popular business in the IT sector. Video dewarping is one of its special fields that expands rapidly. As the requirement of video quality becomes higher and higher, there is an increasing need for efficient solutions that can be utilized to process videos in attempts to gain desirable results. The problem is to determine the right combination of transmission bitrate and resolution for live streaming of the dewarped videos. The purpose of this thesis is to develop a prototype solution for dewarping video from fisheye camera and re-stream it to a client. This prototype is used for testing combinations of bitrate and resolution of the video in different scenarios. A system is devised to live stream a video from a fisheye camera, dewarp the video in a server and display the video in media players. The results reveal that the combination of bitrate 3.5 - 4.5 Mbps and resolution 720p is best suited for transmission to avoid noticeable lagging in playback. Comments of observers prove the promising use of the dewarped videos as Virtual Reality(VR) technology.Direktsänd videoströmning från en kamera med fiskögaobjektiv är ett populärt och snabbväxande, speciellt inom vissa områden som videoförvrängning korrigering. Eftersom kravet på hög högkvalitativ video blir högre och högre, ökas också behovet av en effektiv videobearbetnings lösning för att få önskvärda resultat. Problemet är att bestämma rätt kombination av överföringsbithastighet och upplösning för direktströmning av bearbetade videon. Syftet med detta examensarbete är att utveckla en prototyplösning som korrigerar videoförvrängning från en kamera med fisköga-objektiv samt vidaresända den korrigerade videon till en klient. Denna prototyp används för att testa olika kombinationer av bithastighet och upplösning i olika scenarier. Ett prototypsystem utvecklades för att direktsända video från en kamera med fisköga-objektiv, korrigera videoförvrängningen i en server och spela upp de korrigerade video i en mediaspelare. Resultatet visar att kombinationen av bithastigheten mellan 3.5 - 4.5 Mbps och upplösningen 720p är den mest lämpliga för att undvika märkbara fördröjningar hos klienten. Den potentiella framtida användningen av den bearbetade videon inom Virtuell verklighet (VV) är lovande baserat på observatörernas kommentarer.
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Torche, Fayçal. "Contribution à l'étude des électrons solvatés dans l'eau et les alcools et des processus radiolytiques dans les carbonates organiques par radiolyse impulsionnelle picoseconde." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-01023535.
Full textAbstract:
Le travail présenté dans cette thèse, s'inscrit dans le domaine d'étude de l'interaction des rayonnements ionisants avec les liquides polaires. Bénéficiant de l'accélérateur d'électrons picoseconde ELYSE, les études ont été menées en utilisant les techniques de la radiolyse impulsionnelle associées à la spectrophotométrie d'absorption résolue en temps dans le domaine de la picoseconde. Ce travail est réparti sur deux chapitres distincts. Le premier aborde l'étude la variation temporelle du rendement radiolytique de l'électron solvaté dans l'eau et les alcools simples. Grâce au système de détection original monté sur l'accélérateur ELYSE, composé d'une lampe flash spécialement conçue pour cette détection et d'une streak-camera utilisée pour la première fois en spectroscopie d'absorption, il a été possible d'enregistrer la totalité du déclin du rendement radiolytique de l'électron solvaté d'une façon continue dans un intervalle de temps allant de la dizaine de picoseconde à quelques centaines de nanoseconde. La capture de l'électron solvaté par le méthylviologène, a été mise à profit pour réévaluer le coefficient d'extinction molaire du spectre d'absorption de l'électron solvaté dans l'eau et l'éthanol à partir des points isobestiques qui apparaissent à l'intersection des spectres d'absorption de l'électron solvaté qui disparaît et du méthylviologène qui se forme au cours de la réaction.Le deuxième chapitre est consacré à l'étude des carbonates organiques liquides, tels que le diméthyle carbonate (DMC), le diéthyle carbonate (DEC) et le propylène carbonate (PC). Cette famille de carbonate qui n'a jamais été étudiée auparavant par radiolyse pulsée, entre dans la composition des électrolytes des batteries notamment au lithium. Les études ont été focalisées sur le PC au vu de ces caractéristiques physico-chimiques, notamment sa constante diélectrique très élevée (64) et son très fort moment dipolaire de 4,9 D. Les premiers résultats ont été obtenus d'abord sur des solutions aqueuses contenant du propylène carbonate afin d'observer les réactions de réduction et d'oxydation du PC par les espèces radiolytiques de l'eau (électron solvaté et radicaux OH). Puis après l'identification (spectrale et cinétique) de l'espèce formée par interaction avec le radical OH comme étant le radical PC* résultant de l'abstraction d'un H de la molécule de PC et l'espèce formée par interaction avec l'électron aqueux comme étant l'anion PC-, d'autres mesures ont été effectuées dans le liquide pur ainsi qu'en présence de certains intercepteurs d'électrons (biphényle, anthracène, naphtalène). Elles ont permis d'accéder au rendement radiolytique de PC- ainsi qu'à l'évaluation de son potentiel redox. Les premiers résultats sur le DEC et le DMC sont aussi exposés dans cette partie, portant dans un premier lieu sur le solvant pur et puis en présence de biphényle.
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Howard, Shaun Michael. "Deep Learning for Sensor Fusion." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1495751146601099.
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Durães, Bruno José Rodrigues. "Trabalhadores de rua de Salvador : precarios nos cantos do século XIX para os encantos e desencantos do século XXI." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/281561.
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Orientador: Ricardo Luis Coltro AntunesDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias Humanas
O exemplar do AEL pertence a Coleção CPDS
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Resumo: O presente estudo tem como objetivo central evidenciar e problematizar as condições precárias de trabalho dos trabalhadores de rua da cidade de Salvador em dois contextos díspares, um do final do século XIX (no contexto da abolição da escravidão) e o outro da atualidade (século XXI), evidenciando importantes elementos de similitudes, bem como, de incongruências. O problema que norteia a investigação proposta divide-se em dois. Pelo lado do século XIX ensejou-se responder a seguinte indagação: As formas de trabalho de rua de Salvador do final do século XIX representaram uma forma de trabalho avançada em relação a forma de trabalho predominante à época, a escrava? Por outro lado, referente às formas de trabalho de rua da atualidade, indagou-se: Serão estas formas de trabalho de rua atuais atrasadas em relação às formas de trabalho assalariado/formal da moderna produção capitalista, representando assim um retrocesso?Para responder a estas questões nos valemos do recurso da historiografia para o século XIX, compondo o cenário de vida e de trabalho das ruas da cidade de Salvador de finais deste século, utilizando de documentos e recortes de jornais históricos. Outrossim, para a atualidade usamos de uma pesquisa qualitativa com 191 trabalhadores de rua espalhados em diversos pontos da cidade de Salvador, e também de notícias em jornais. Estas bases permitiram compor duas paisagens de uma mesma cidade, em situações diferenciadas, mas que retratam formas similares de trabalho, principalmente, por estarem todas localizadas nas ruas da capital baiana. No século XIX os/as trabalhadores/as de rua eram denominadas de ganhadores/ganhadeiras e se encontravam ordenados/as em cantos delimitados na cidade. Hoje, são conhecidos/as como camelôs, vendedores/as ambulantes, informais e estão situados em todos os cantos da cidade, ainda com regulamentações, perseguições e ordenações, e uma máxima vem a tona, a saber, a busca frenética e incansável pela sobrevivência
Abstract: This present study has the main objective of evidence and discuss the precarious labour conditions of street workers on the city of Salvador in two different contexts, one is the end of the XIXth century (in the context of slavery abolition) and other is the present time (XXIth century), evidencing important elements of similarities, as well as, the incongruence. The problem that guides this inquiry is divided in two pieces. On the XIXth century, it was tried to answer the following investigation: the forms of street labour on Salvador's streets at the end of XIXth century had represented an advanced form of labour in comparison with the predominant form of labour at that time, the slave labour? On the other hand, referring to the forms of street labour at the present time, it was inquired: Have these current forms of street labour been less developed in comparison with the forms of formal wage-earning labour on the modern capitalist production, therefore, it represents a retrocession? To answer these questions, it was necessary the use of XIXth century historiography, to compose the scene of everyday life and work on the streets of Salvador at the end of this century, using documents and clippings of historical periodicals. So, on present time, we use a qualitative research with 191 street workers in diverse locations around the city of Salvador, and also clippings of actual periodicals. These bases had allowed composing two pictures of the same city, in differentiated situations, portraying similar forms of labour, all of it located on Salvador¿s streets. In XIXth century, the street workers were called of earners and they were found in delimited corners around the city. Today, they are knowed as ambulants, informal peddlers and sellers, and they are situated in all the corners around the city, still constrained by regulations, persecutions and ordinances, and a principle comes up: the frantic and untiring struggle for survival
Mestrado
Mestre em Sociologia
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Teles, Alessandra Oliveira. "O comércio informal em Feira de Santana (BA) : permanências e mudanças." Pós-Graduação em Geografia, 2017. https://ri.ufs.br/handle/riufs/6822.
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Informal trade in Feira de Santana, specially the one located on the streets downtown, has gone through significant changes from the beginning of the organization of the city with the street market and the cattle fair up to the city’s present organization with predominant industrialized products. The situation indicates that processes of capital accumulation have been included in the activity. The organization and relevance of such activity is the reflex of the power it possesses when it comes to attracting a great flow of people, mostly from the city’s micro region, and of the capacity of promoting the circulation of capital, characterizing the commercial center as a venue of great value for any kind of informal trade, including street market. Commerce is the strength of Feira de Santana’s economy. In this perspective, informal trade has become the focus of this study, considering its relevance. Continuity and changes in street trade in Feira de Santana are local result of global situation. Changes in the international scenario stablished over a short period of time will reset nations and cause significant economic and political changes in the contemporary world. The practice of street trade is a well-known model which gained new patterns if we consider what is commercialized presently since the street market is responsible, mostly, for commercializing agricultural or manufactured products. At the present organization, industrial production, mostly technological, is dominant in this kind of commerce. It is the result of a consolidating historic process, governmental actions, labor laws, as well as changes in production and labor relations at global level with local repercussions which resulted in a process of production restructuration. Furthermore, many citizens make a living out of this activity and many industries increase their capital by selling part of their production to this segment of commerce. Among continuity and changes, it is noticed that the street trade studied follows the logic and model of the society for which it is destined. In this context, trade conducted by street vendors has reflected clients’ needs and interests. The conclusion of this research shows that informal trade in Feira de Santana presents great heterogeneity, complexity and relevance for society and economy. Therefore, continuity and changes in the activity allow several further studies.O comércio informal em Feira de Santana, particularmente o que ocorre nas ruas da cidade, passou por significativas transformações no intervalo que marca a origem do município e da cidade com a feira livre e a feira de gado bovino até a atual organização. Esta situação é um indicativo de que houveram inclusões de processos de acumulação de capital. Sua organização e relevância é reflexo do poder que possui em atrair um elevado fluxo de pessoas, em especial, de sua microrregião, e da capacidade em promover a circulação de capital, caracterizando o centro comercial como local de maior valor para todo tipo de comércio informal, incluindo o comércio de rua. É no comércio onde se encontra a força da economia de Feira de Santana, nesta perspectiva, determinou-se o comércio informal como objeto desse estudo, considerando sua relevância. Como tese foi estabelecido: A centralidade urbana em Feira de Santana se mantém perante o fortalecimento do circuito inferior da economia representado pelo comércio de rua realizado por ambulantes e camelôs. As permanências e resistências no comércio de rua em Feira de Santana também são repercussões locais de situações globais. O objetivo geral busca analisar o comércio informal em Feira de Santana, sua evolução e transformação reafirmando a centralidade associada à dinâmica urbana e popularização do consumo. As informações indispensáveis para a realização desta pesquisa foram organizadas a partir de fontes diversas. Os documentos governamentais foram consultados. Os dados estatísticos indicativos à população, os censos demográficos e informações sobre o comércio foram coletados no site do Instituto Brasileiro de Geografia e Estatística. Ainda foi realizada uma pesquisa de campo com a intenção de identificar o perfil dos ambulantes e camelôs, além dos consumidores. Esta forneceu dados para a elaboração e discussão dos resultados apresentados no formato de texto, gráficos figuras, tabelas e mapas temáticos. Entre as permanências e mudanças evidenciadas percebe-se que o comércio de rua estudado segue a lógica e modelo de sociedade para o qual se destina. Nesse sentido, o comércio realizado por ambulantes e camelôs vem refletindo interesses e necessidades da clientela. O espaço público representado pelas ruas e avenidas do centro comercial da cidade de Feira de Santana confirma-se enquanto espaço para o comércio de rua realizado por ambulantes e camelôs. A tradição histórica da feira livre, o desemprego promovido pelas sucessivas reestruturações produtivas, a articulação local, regional e nacional para a realização da atividade comercial contribui para a consolidação do comércio formal e também do informal. Os logradouros estudados apresentam graves problemas de infraestrutura e ordenamento territorial que se corrigidos pelo poder público, não inviabilizam sua realização, principalmente por ser referência em escala regional.
São Cristóvão, SE
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Korchakov, Sergei. "Zpracování obrazu v systému Android - detekce a rozpoznání obličeje." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220900.
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This master’s Thesis focuses on image processing on Android platform and development of an application, that is able to do face detection and recognition in real scene. Thesis gives highlight of modern algorithms of face detection. It first examines and compares the standard features of Android platform (FaceDetector a FaceDetectionListener) and JJIL, OpenIMAJ, OpenCV libraries experiment, and presents the results. For purposes of face recognition was selected OpenCV library. Three different algorithms of identification were tested: FisherFaces, EigenFaces a Local Binary Patterns Histograms. Based on performance comparison best methods were implemented in developed application.
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Maillot, Sacha. "Fluorescence picoseconde de complexes bio-moléculaires hors équilibre dans un écoulement microfluidique." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00957957.
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Ce travail de thèse a démontré la possibilité de mesurer la relaxation d'un complexe biomoléculaire ainsi que son hétérogénéité structurale, en associant la microfluidique et la fluorescence résolue en temps (FRT). Je présente de quelle façon la FRT permet d'obtenir une information sur la structure d'une molécule et comment on la mesure, notamment grâce à une caméra à balayage de fente. J'introduis ensuite la microfluidique de gouttes, permettant de mélanger deux réactifs en quelques millisecondes et de suivre la relaxation du complexe au cours de la propagation des micro-réacteurs. Puis, la mesure d'une cinétique avec un couple de molécules modèle démontre la preuve de principe, faisant l'objet d'un article soumis. Enfin la mesure de FRT par comptage de photons uniques dans des gouttes uniques est décrite. Elle ouvre une perspective d'application pour le criblage à haut débit : un brevet a été déposé.
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Johnson, Betty J. PhD. "Video Meetings in a Pandemic Era: Emotional Exhaustion, Stressors, and Coping." Antioch University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1612609329629973.
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Chen, Tsung-Huang, and 陳宗煌. "Hardware-Oriented Demosaicking Algorithm and Design of Dual-Stream Reconfigurable Image Signal Processor for Digital Still Cameras." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/41424112940202082926.
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碩士臺灣大學
電子工程學研究所
96
In recent years, the Digital Still Camera (DSC) has been widely adopted as an image capture device for PC-based multi-media system. A digital still camera can capture images by using a CCD or CMOS sensor and then compress the data to store the images on a memory card. In order to reduce the cost and size, many digital cameras use a single image sensor with a color filter array (CFA) to capture images. Because each pixel only contains one of the three primary colors in CFA, the others must be estimated from the neighboring pixels. This process is called as CFA demosaicking. Generally speaking, there are two artifacts generated in the process of interpolation,including zipper effect and false color artifacts. Many state-of-the-art demosaicking methods are proposed to reduce these artifacts for achieving better image quality perceptually and in PSNR. However, hardware cost for VLSI implementation is not considered in most of them. Therefore, a hardware-oriented CFA interpolation algorithm is developed in this thesis according to the hardware cost analysis results. The proposed algorithm is by use of chrominance variance weighting scheme interpolation. Experimental results show that our method can achieve good image quality in PSNR than the existing methods on variety of test images while low hardware cost is still maintained. It shows that this method can be a good compromise between image quality and hardware cost. Besides, we also evaluate mostly used existing solutions to image processor, including DSP, ASIC, hybrid solution and CRISP [2]. DSP owns high flexibility and can handle almost all kinds of image pipeline tasks in a DSC system, but the cost is much higher and it can’t meet the real-time requirement in the preview mode. The application-specific-integrated-circuit (ASIC) solution is highly optimized in terms of area, power and speed to perform its designated task, but it, however, doesn’t have much flexibility for different algorithms in the picture-taking mode. The hybrid solution combines the advantages of DSP and ASIC but the hardware utilization is low and the cost is too high. Therefore, a coarse-grain reconfigurable image processor, CRISP, has been proposed to solve this problem. It can approach the hardware cost lower bound of preview engine caused by the real-time constraints in the preview mode. In addition, the flexibility requirement in the picture-taking mode can be achieved by the reconfigurability of CRISP. The high processing speed can also be achieved by the processing elements specially designed for image processing tasks by utilizing the algorithmic similarity. In summary, CRISP combines the advantages of ASIC and DSP into a single hardware by proper time-space tradeoff in different modes. The high flexibility and efficiency of CRISP is very suitable for image pipeline in DSC. Therefore, in order to upgrade the image or video quality in the preview mode, we follow the concept of CRISP and propose a dual-stream reconfigurable image stream processor (CRISP-DS) with a new design idea, called dual stream with context switch. The concept of dual-stream with context switch is to combining these characteristics in the preview and picture-taking mode. In the preview mode, inside the interface of CRISP-DS, there is a PLL (Phase lock loop) to generate the frequency twice than sensor frequency and to synchronize it. Then the data stream and synchronization signal are modified such that there are two cycle to process a pixel, which concept is similar to data stream rate adjustment in the picture-taking mode. Then we double the context for some reconfigurable stage processing elements (RSPEs) and each context is corresponding to the each one of two cycles, which means each RSPE can be configured as two different image pipeline algorithms. Then a better image pipeline can be employed in the concept meanwhile the overhead of gate count to implement this pipeline is mush smaller than original CRISP design. The CRISP-DS chip is fabricated with TSMC 0.13um 1P8M CMOS process via CIC. The chip die size is 3.18 mm x 3.18 mm and the core size is 2.2 mm x 2.2 mm. The max working frequency in preview mode is twice than the frequency of the sensor and 200Mhz in picture-taking mode. The average total power consumption at 200 MHz is 314 mW. The total on-chip SRAM bit number is 104,192 bits. For the golden test image pipeline, the implementation results demonstrate that the area and power efficiency of CRISP-DS are better than CRIPS. In additions, the processing speed of CRISP-DS is 6 times faster than CRISP and over 250 times fasters than TMS320C64x DSP.
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Chen, Tsung-Huang. "Hardware-Oriented Demosaicking Algorithm and Design of Dual-Stream Reconfigurable Image Signal Processor for Digital Still Cameras." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-0910200721033900.
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Opachich, Yekaterina P. "Time resolved ultrafast demagnetization of Co₂MnSi observed by X-ray magnetic circular dichroism and an ultrafast streak camera." Diss., 2009. http://proquest.umi.com/pqdweb?did=1987511271&sid=1&Fmt=2&clientId=48051&RQT=309&VName=PQD.
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SONG, JIE-LIN, and 宋玠霖. "Fast Pitch-Strike Recognition in Fixed-camera Baseball Videos with YOLO-based Two-stream Network and Approximated Optical Flow." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/z44yxy.
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碩士國立中正大學
電機工程研究所
106
As more and more people get interested and involved in sports, collecting and analyzing the skills, preference tactics, etc., of key athletes is becoming common and even necessary. Moreover, frequent sport events have prompted for quick and effective analysis. This thesis focuses on recognizing pitches and strikes in a baseball game footage. We first identify potential video segments by background filtering and action detection. Then, we apply the two-stream CNN to further recognize pitches and strikes in the selected video segments. To improve the operation efficiency, we also employ a fast CNN to do object recognition, and subsequently simplify the computation of optical flow. Experience shows that the method proposed in thesis paper can improve the computational efficiency by 75%, and the model accuracy is improved by 25 mAP in the self-collected baseball dataset.
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(5929814), Ravichandra R. Jagannath. "Development of Plasma Assisted Ignition for Wave Rotor Combustion Turbine." Thesis, 2019.
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Gas turbines are important for power generation and aircraft engines. Over thepast century, there has been improvements in components of the gas turbine such ascompressors, turbines and nozzles, but very little progress has been made in combustor technology. The combustion still occurs at constant pressure and the only changes made are in terms of its design and mixing of fuel and air streams. These design changes have only allowed minimal improvements in gas turbine efficiency. To achievea substantative improvement in efficiency, it is required to make a technology change such as the introduction of constant volume combustion.In this work, one such constant volume combustion device in the form of wave rotor combustion is studied and further developed for use in gas turbines. Wave rotors are periodic-flow devices that provide dynamic pressure exchange and efficient energy transfer through internal pressure waves generated due to fast opening and closing of ports. In addition, there is also confined high speed turbulent deflagration. If the blades are curved, then the flow undergoes angular momentum change from inlet to outlet, generating shaft work. This will allow maximum extraction of work potential from the wave rotor. In addition, an attempt is made to check the applicability of plasma assisted ignition for wave rotors.
A computational tool is developed to understand physics of non-axial channelwave rotors. The governing equations are formulated in one dimension through a passage average approach. Shaft work is estimated using conservation of angular momentum and enrgy to verify the working of numerical model. The model shows increase in shaft work with increase in blade curvature, but as the angle is increased, the possibility of ignititing the reacting mixture becomes difficult since it is hard tomove the mixture towards the ignition port.
An alternate ignition source using plasma discharges is investigated through experiments. Two experiments are developed, one to make ultrafast measurements of plasma properties such as gas heating and lifetime of electronically excited molecules, and a second experiment to understand ignition characteristics of a pin to ring electrode configuration. The experiments show that excited nitrogen which reacts with molecular oxygen to form atomic oxygen is short lived and forms oxygen atoms extremely rapidly. This rapid formation of oxygen atoms assists in fast ignition. The ignition experiment with pin to pin electrode showed that even though there is fast ignition, the propagation speed does not change significantly with pulse repetition frequency. Ignition with pin to ring electrode showed fast ignition and increase inflame speed with pulse repetition frequency. Results show that plasma discharge can be used as an ignition source for wave rotors but will need further investigation.
The development of computational tool and plasma discharge experiments has provided a solid base for future efforts in wave rotor combustion and design of full scale non-axial wave rotor combustor experiment.
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Ilies, Dragos-Bogdan. "In-field characterization of salt stress responses of chlorophylls a and b and carotenoid concentrations in leaves of Solanum pimpinellifolium." Thesis, 2018. http://hdl.handle.net/10754/630024.
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Food security is a major concern of the 21st century, given climate change and population growth. In addition, high salt concentrations in soils affect ~20% of irrigated land and cause a substantial reduction in crop yield. Cultivating salt-tolerant crops could enable the use of salt-affected agricultural land, reduce the use of fresh water and alleviate yield losses. Innovative methods need to be developed to study traditional and novel traits that contribute to salinity tolerance and accurately quantify them. These studies would eventually serve for developing new salt tolerant crops, adapted to the harsh arid and semi-arid climate conditions. A study of 200 accessions of the wild tomatoes (Solanum pimpinellifolium) was conducted in field conditions with phenotyping using an unmanned aerial vehicle (UAV)-mounted hyperspectral camera. Six genotypes with different levels of salt tolerance were sampled for leaf pigment analyses, revealing a clear pattern for the high salt tolerant accession M007, where pigment content in the salt-treated plants significantly increased compared to their control counterparts only in harvesting campaigns 3 and 6, each performed two days after the first and second salt stress application events. Moreover, the light harvesting capacity was found to be better maintained under salt stress in the medium (M255) and highly salt tolerant (M007 and M061) accessions. Pigment quantitation data will contribute towards the groundtruthing of hyperspectral imaging for the development of remote sensing-based predictive pigment mapping methods. This work establishes a reliable quantification protocol for correlating pigment content with vegetation indices.
Hence, pigment content captured by imaging techniques and validated using biochemical analysis would serve in developing a high-throughput method for pigment quantitation in the field using UAV-based hyperspectral imaging. This would serve as a tool for measuring pigment content in large number of genotypes in the field which would eventually lead to new salt-tolerant genes.
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Koppe, Tristan. "Untersuchungen zum Lumineszenzverhalten des Aluminiumnitrids und der Aufbau einer Kurzzeit-Lumineszenz-Spektroskopie-Apparatur." Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3E9D-F.
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Gombojav, Ariunbold. "Ultrafast Cooperative Phenomena in Coherently Prepared Media: From Superfluorescence to Coherent Raman Scattering and Applications." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9058.
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Technological progress in commercializing ultrafast lasers and detectors has allowed realization of cooperative processes on an ultrashort time scale, which demand a re-evaluation of the conventional cooperative phenomena with a new insight. Ultrafast cooperative phenomena in coherently prepared media and various applications of superfluorescence and coherent Raman scattering are studied in this dissertation. In particular, a simple theoretical testimony on analogy between a cooperative emission and coherent Raman scattering is presented by offering an opportunity to perform parallel research on these two processes from a unified point of view.
On one hand, the superfluorescent pulse with a time duration of a few tens of picoseconds (ps) from alkali metal vapor is observed for the first time, even though cooperative phenomena in atomic vapor have been extensively studied for more than five decades. A dense rubidium vapor pumped by ultrashort (100 femtosecond, fs) pulses allows a realization of the ultrafast superfluorescence while a time-resolved study of superfluorescence is accomplished by using a streak camera with 2 ps time resolution. Experimental research on quantum nature of cooperative emissions has been “frozen” over the years (three decades) possibly because of the technical difficulties. Quantum fluctuations of superfluorescence development are explored experimentally by taking advantage of the ultra fast streak camera. Presumable applications of the superfluorescent pulse in e.g., a remote sensing, and an ultraviolet upconversion of the input infrared laser pulse are presented. The quantum interference due to different excitation pathways is revealed by the temporal coherent control technique while observing interferometric signals from alkali metal vapors.
On the other hand, a new spectroscopic technique based on ultrafast coherent Raman scattering is developed. The key advantage of the presented technique is to suppress the non-resonant background noise which usually obscures possible applications of the other conventional coherent Raman techniques in practice. A reduction of the background noise is achieved by shaping and delaying the third pulse which probes the coherence of the medium (i.e., an enhancement of specific vibrations of the target molecules in unison) firstly prepared by two broadband pulses. We demonstrate a robustness and superiority of signal-to-noise ratio of the developed technique by identifying as few as 10000 bacterial spores at a single laser shot level.
Finally, several comparative studies between cooperative and uncooperative processes are presented. A picosecond cooperative phenomenon in a three-photon resonant medium induced by a single as well as two-color ultrashort pulses is investigated. A time-resolved study shows that a picosecond cooperative effect is crucial in the well-established fields of resonant-enhanced multiphoton ionizations and harmonic generations. We also present a quantitative analysis for spontaneous versus broadband coherent Raman scattering on pyridine molecules. The spontaneous Raman signal is enhanced by 5 orders as a result of cooperative phenomena.
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Duguay, Raphaël. "Évaluation de rafles policières successives contre un réseau de revendeurs de stupéfiants." Thèse, 2008. http://hdl.handle.net/1866/7403.
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Mendonça, Luís Guilherme Jordão de. "As Imagens de Morris Engel e Ruth Orkin: O Berço da Modernidade no Cinema." Master's thesis, 2010. http://hdl.handle.net/10362/123981.
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Esta dissertação debruça-se sobre a obra de Morris Engel e Ruth Orkin. Com base em textos e teorias de André Bazin, Alain Bergala, Jonas Mekas, Georges Sadoul e Richard Leacock, procuramos dar sustentabilidade à ideia (apontada por estes autores) que Little Fugitive (1953) é o “elo que falta” entre a fotografia de rua, o neo-realismo italiano e o nascimento do cinema independente norte-americano tal como da Nouvelle Vague francesa; e que se deve a Morris Engel a paternidade do primeiro sistema síncrono som-imagem inteiramente móvel, posto à prova na sua última longa-metragem, Weddings and Babies (1958).This dissertation deals with the work of Morris Engel and Ruth Orkin. Supported by the texts and theories of André Bazin, Alain Bergala, Jonas Mekas, Georges Sadoul and Richard Leacock, I try to sustain the idea (pointed out by these authors) that Little Fugitive is the “missing link” between street photography, the Italian neorealism and the birth of the American independent cinema as such as the French New Wave; and that Morris Engel is the inventor of the first fully mobile, synchronous sound-and-picture system, which was tested in his last movie, Weddings and Babies (1958).