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Détection Térahertz par transistor à effet de champ à base de Silicium. / THz detetection with Silicon Field Effect TransistorsVidelier, Hadley 02 December 2010 (has links)
Ce travail expérimental traite de la détection de radiations Térahertz (THz) par des transistors à base de silicium. Après avoir exposé le contexte de l'étude et les bases théoriques des modèles nécessaires à la compréhension du sujet, le manuscrit débute par une comparaison des transistors de haute mobilité électronique (HEMTs à base de matériaux III-V), aux transistors à base de silicium (Si-MOSFETs). Cette étude permet une meilleure compréhension du mécanisme physique responsable de la détection de radiations THz par les transistors à effet de champ de manière générale. La seconde partie de ce travail est consacrée à l'étude théorique et expérimentale de la longueur critique du canal Lc, liée à la distance d'amortissement des ondes de plasma et à partir de laquelle le signal de détection sature. Par ailleurs, le signal de détection THz de différents types de Si-MOSFETs a été étudié en fonction du champ magnétique, de la température et de la fréquence de l'onde THz incidente. Des raies inattendues et extrêmement marquées sont observées, jusqu'à la température ambiante, dans le signal de détection et dans la résistance du canal en champ magnétique. Celles-ci semblent être liées à une résonance de spin de facteur gyromagnétique égal à 2. L'allure générale du signal THz en champ magnétique est également discutée. Enfin, l'une des premières générations de détecteurs optimisés pour le THz et conçue dans le cadre d'un partenariat avec le CEA-LETI est présentée. Il s'agit notamment d'une matrice de pixels composés de Si-MOSFETs connectés à des antennes adaptées, à des amplificateurs de signaux, et à une première ébauche de circuit de lecture. La sensibilité, la puissance équivalent bruit (NEP) et la polarisation de ces détecteurs, est également étudiée en fonction de la fréquence incidente. Les résultats de cette étude mettent en exergue le potentiel de ces transistors nanométriques à base de Silicium entant que détecteur dans un système d'imagerie THz performant à température ambiante. / The experimental study reported here, deals with Therahertz (THz) radiation detection with silicon based transistors. After a brief overview of the context and the basics of the theory necessary to understand the subject, the report starts with a comparison betwen high mobility transistors (HEMTs based on III-V technolgies), and silicon transistors (Si-MOSFETs). This study allows a better understanding of the physical phenomenom responsible for THz radiation detection with field effect transistors in general. The second part is focalized on theoretical and experimental study of the critical chanel length (Lc), correlated to the distance of the plasma waves damping, from which the detection signal saturates. Beside, this THz detection signal, from diffrent kind of Si-MOSFETs, has been studied in magnetic field, in temperature, and in the frequency of the incomming radiation. Very pronounced and odd peaks are observed and studied, up to the ambiant temperature, inside the THz signal and the resistance of the MOS submited to magnetic field. These peaks seems to be linked by some way to a spin resonnance with a gyromagnetic factor of 2. The global tendancy of the evolution of the signal in magnetic field is also studied. Finally, one of the first generation of THz optimized detectors, develloped in partnership with CEA-LETI, is presented. Indeed, matrixes of pixels, composed of Si-MOSFETs connected to specific antennas, integrated amplifiers, and a basic reading circuit are studied. Sensitivity, noise equivalent power (NEP), polarization, of these detectors are caracterized. This study demonstrates the whole potential of these silicon based transistors as efficient THz imagery detectors for room temperature.
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Letting in the Night: The Moon, the Madwoman, and the Irrational Feminine in Jane Eyre and Wide Sargasso SeaRosenthal, Sophia 01 January 2017 (has links)
This analysis examines Jane Eyre and Wide Sargasso Sea through the lens of lunar imagery and the irrational feminine, arguing that both texts are aspects of an extended, collective narrative in which both heroines rescue and reclaim their feminine essence from the construction of a masculine idealism.
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Imagery, Psychotherapy, and Directed Relaxation: Physiological CorrelatesBaldridge, Jeffrey T. (Jeffrey Turner) 05 1900 (has links)
Thirty outpatients being treated at Wilford Hall USAF Medical Center Department of Behavioral Health Psychology were randomly assigned to either a relaxation/imagery training class (R/I), a short-term psychotherapy group (P/G) or a no treatment control group. Subjects had psychological, physiological and immunological data taken before and after treatment. Results indicated that support for the hypothesis that relaxation/imagery training improves the psychological, physiological, and immunological functioning of participants was found.
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Health Attribution, Client Motivation, and Problem Imagery in the Rehabilitation Applicant: A Study of Rehabilitation OutcomeDrake, Roy Vernon 12 1900 (has links)
One hundred persons applying for services with the Texas Rehabilitation Commission with reported disabilities of alcohol/substance abuse or back injury/pain were selected for study. Subjects were assigned to two groups (alcohol or back) according to their reported disability. They were tested within one week of application and after 60 days were checked to see what rehabilitation status they were in to determine success or failure. Alcohol clients were administered the Health Attribution Test (HAT), 16PF, and an Alcohol Imagery questionnaire developed for this study. Back clients were administered the HAT, 16PF, and Pain Drawings. Statistical procedures including Pearson correlation, stepwise discriminant analysis, and discriminant analysis were performed. The HAT Internal Factor showed a significant relationship to rehabilitation success or failure and the 16PF motivation indices approached significance. The discriminant analysis demonstrated that success or failure could be predicted at a significant level using these measures. Issues of practicality in using these instruments (particularly imagery measures) in a rehabilitation counseling practice were noted.
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Robert Grosseteste as Mentor to William of ShorehamTindall, Betty Jenson 05 1900 (has links)
The problem scrutinized in this thesis is the relationship between Robert Grosseteste, mentioned in the colophon of William of Shoreham's "Song to Mary," and the author of said poem. The influence of Grosseteste on William of Shoreham appears to be extensive. Many similarities of organization, diction, and, especially, imagery, exist in the works of both men. The images of the windowpane, the mirror, and Mary as a castle are found in more than one instance in both Grosseteste's Chasteau d'Amour and in several of Shoreham's poems. Moreover, the borrowed imagery in Shoreham's poetry is unquestionably superior to any other in his works. It is the conclusion of this thesis that Robert Grosseteste was a considerable influence on the works of William of Shoreham.
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A Novel P300 speller with motor imagery embedded in a traditional oddball paradigm.Karnad, Vaishnavi 05 May 2011 (has links)
A Brain Computer Interface (BCI) provides a means, to control external devices, through the electrical activity of the brain, bypassing motor movement. Recent years have seen an increase in the application of P300 cognitive potential as a control and/or communication signal for the motor restoration in paralyzed patients, such as those in the later stages of ALS (Amyotrophic lateral sclerosis). Although many of these patients are in locked-in state i.e. where motor control is not possible, their cognition is known to remain intact. The P300 speller paradigm explored in this study relying on this cognition represented by the P300 peak potential in EEG (Electroencephalography) signals to restore communication. The conventional visual oddball paradigms used to elicit P300 potential may not be the optimum choice due to their need for precise eye-gazing, which may be challenge for many patients. This study introduces a novel paradigm with motor imagery as a secondary after-stimulus task in a traditional visual oddball paradigm for P300 Speller application. We observed increased P300 peak amplitude as well as the event-related desynchronization (ERD) associated with motor imagery in six healthy novice subjects. Acceptable detection accuracy was obtained in the five-trial averaged signals from 250 ms to 750 ms after the visual stimulation, whereby the early visual evoked potentials were excluded from classification. As an enhancement, efforts are being made to assess implementation by motor imagery embedded in an auditory oddball paradigm which would minimize the need for eye-gazing further. We can conclude from the results of this study that the proposed paradigm with motor imagery embedded in a traditional visual oddball paradigm might be a feasible option for communication restoration in paralyzed patients.
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Klasifikace silniční sítě z dat leteckého laserového skenování a optických dat DPZ vysokého rozlišení / Classification of road network from airborne laser scanning data and from remote sensing images with high resolutionKuchařová, Jana January 2013 (has links)
Classification of road network from airborne laser scanning data and from remote sensing images with high resolution Abstract Object classification of land cover is currently one of the methods of remote Earth exploration. Road network classification only is unique because it is covered with anthropogenic material and has different characteristics than other elements of the landscape. This work deals with the possibility of using a combination of data from airborne laser scanning and high resolution optical data for detection of the road network in the specific area. The premise is that the use of two different types of data could provide better results, because airborne laser scanning data provide very precise information about the position and height of the point, while satellite data of very high resolution represent the real landscape. Searching for suitable features and classification rules for unambiguous determination of the road network is one of the objectives of the work. Segmentation parameters will also be important for object classification. Another objective is to verify the transferability of classification schemes into the other scene. The results should present a response on whether a procedure can be applied over a different location and also that the use of two types of data can bring...
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Loď jako prostor střetávání života a smrti: nautická metaforika v literární moderně / The ship as a point of encounter between life and death: nautical metaphor in modern literatureOndroušková, Světlana January 2014 (has links)
6 Abstract The diploma thesis concerns the topic of nautical metaphorics in modern literature in a broad sense of the term as defined by Silvio Vietta. Thus besides the topic itself and its main focus on the work of Franz Kafka it also covers the process of evolution of its attributes, which led to the specific imagery of modernism on the brink of the 20th century. The work as a whole derives from the conception of the nautical space as a smooth space of nomadism as proposed by Deleuze and Guattari. The first part is based on the propositions of Bachelard's theory of material imagination. It deals with the characteristics of the literary space shaped by the sea element and the possibility of alogorical reading of such images. The hydraulics of the sea provides the nautical space with its unique qualities: shapelessness, flexibility and ambivalence. These enable to percieve the nautical space not only as the space of happenings, but also as the happenings of the space. Thus it puts emphasis on the activity and dynamic plasticity of the substance. The second part reveals the ancient and Christian roots of nautical imagery and its tradition in the European literature. The work of Comenius exemplifies the change in the symbolism of the ship with the arrival of the Age of Exploration which rendered the ship a...
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Principal components based techniques for hyperspectral image dataFountanas, Leonidas 12 1900 (has links)
Approved for public release; distribution in unlimited. / PC and MNF transforms are two widely used methods that are utilized for various applications such as dimensionality reduction, data compression and noise reduction. In this thesis, an in-depth study of these two methods is conducted in order to estimate their performance in hyperspectral imagery. First the PCA and MNF methods are examined for their effectiveness in image enhancement. Also, the various methods are studied to evaluate their ability to determine the intrinsic dimension of the data. Results indicate that, in most cases, the scree test gives the best measure of the number of retained components, as compared to the cumulative variance, the Kaiser, and the CSD methods. Then, the applicability of PCA and MNF for image restoration are considered using two types of noise, Gaussian and periodic. Hyperspectral images are corrupted by noise using a combination of ENVI and MATLAB software, while the performance metrics used for evaluation of the retrieval algorithms are visual interpretation, rms correlation coefficient spectral comparison, and classification. In Gaussian noise, the retrieved images using inverse transforms indicate that the basic PC and MNF transform perform comparably. In periodic noise, the MNF transform shows less sensitivity to variations in the number of lines and the gain factor. / Lieutenant, Hellenic Navy
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Les mouvements de membre fantôme : relations entre perceptions motrices et neuro-anatomie fonctionnelle étudiée en IRM fonctionnelle / Phantom limb movements : kinesthetic perceptions and functional neuroanatomy in fMRIRaffin, Estelle 29 September 2011 (has links)
Le membre fantôme correspond à la persistance de perceptions sensitives et motrices attribuées au membre amputé. Des douleurs chroniques parfois invalidantes ainsi que des capacités d’évocation de mouvements dans le membre absent sont fréquemment rapportées. Très peu connue, cette motricité résiduelle est souvent considérée comme de l’imagerie motrice. Le premier objectif de cette thèse est de réinterroger le statut psychologique des mouvements de membre fantôme. Le second objectif est d’étudier le lien entre le contrôle moteur dans le membre fantôme et les réorganisations corticales dans le cortex moteur du sujet amputé. Au moyen de tests comportementaux et d’examens en Imagerie par Résonnance Magnétique fonctionnelle (IRMf), ces travaux de thèse ont permis de dissocier expérimentalement une forme de perceptions kinesthésiques associée à de l’imagerie motrice et une autre forme associée à de l’exécution motrice dans le membre fantôme. Cette distinction repose à la fois sur des différences de performances et sur le recrutement de régions cérébrales partiellement distinctes. Au-delà de cette distinction physiologique, les résultats obtenus suggèrent que les mouvements de membre fantôme s’apparentent à une forme d’exécution motrice plutôt qu’à de l’imagerie motrice. A travers le modèle du membre fantôme, ce travail aborde donc la question de la nature des informations menant à la perception d’un mouvement comme étant « exécuté ». Les altérations du fonctionnement cortical mises en évidence chez l’amputé peuvent représenter un modèle d’étude intéressant des différents mécanismes physiopathologiques relevés dans des situations de déficiences liées à une forme de plasticité « maladaptative ». Les observations cliniques et les examens en neuroimagerie menés au cours de cette thèse dressent en effet, un modèle relativement cohérent de l’organisation fonctionnelle du cortex après amputation. En particulier, l’existence d’un lien entre les réorganisations fonctionnelles au sein du cortex moteur et la qualité du contrôle moteur résiduel dans le membre fantôme permet de mieux comprendre les mécanismes sur lesquels reposent certaines thérapies antalgiques, comme les thérapies visuomotrices / The phantom limb is a sensory experience that is perceived to originate from the missing part. Amputees report that the phantom limb had certain sensory properties like touch and pain, as well as kinesthetic properties like being able to be moved voluntarily. Phantom limb movements are little-known and generally considered to reflect motor imagery rather than motor execution. The first aim of this thesis is to investigate whether amputees distinguish between executing a movement of the phantom limb and imagining moving the missing limb. The second aim is to examine the link between the quality of the motor control in the phantom limb and cortical reorganizations in the motor cortex of amputees. Behavioral tests and functional Magnetic Resonance Imaging (fMRI) results reveal the ability of amputees to make the distinction between execution and motor imagery in the phantom limb. This distinction is based both on differences in performances associated with the two tasks and the recruitment of partially distinct brain regions. Beyond this physiological distinction, this result suggests that phantom limb movements are similar to executed movements and differ from imagined movements. This raises important questions about the very nature of the processes underlying the awareness of a movement as being executed or imagined. The functional alterations in the motor cortex of amputees are somewhat similar to the pathophysiological mechanisms of maladaptative plasticity. Amputation could be a great model for its study. Indeed, the clinical and neuroimaging examinations conducted during this thesis led to a relatively coherent model of the functional reorganizations in the motor cortex after a limb-amputation and their relationships with behavioral variables. In particular, the relationship between functional reorganizations in the motor cortex and the quality of residual motor control in the phantom limb helps to understand the mechanisms underlying some analgesic therapies, such as the “visuomotor therapy”
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