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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Audition et démasquage binaural chez l'homme / Binaural hearing and binaural masking release in human

Lorenzi, Antoine 14 December 2016 (has links)
Contexte : Le démasquage binaural est un processus indispensable pour la compréhension en environnement bruyant. Ce mécanisme ferait intervenir la comparaison d’indices temporels et fréquentiels tout au long des voies nerveuses auditives. Cependant, il n’existe pas de réel consensus évoquant un traitement du démasquage à un niveau sous-cortical et/ou cortical. L’objet de cette étude est d’étudier ces indices temporels et fréquentiels du démasquage par le biais d’une étude perceptive, puis d’une étude électroencéphalographique (EEG). Matériels et méthodes : Une population normoentendante a été évaluée lors d’une étude perceptive visant à estimer l’importance du démasquage en fonction de 1) la largeur fréquentielle du bruit controlatéral (de 1 octave, 3 octaves ou à large bande), 2) la cohérence temporelle des bruits bilatéraux (corrélation égale à 0 ou 1) et 3) la fréquence des stimuli cibles (0,5, 1, 2 et 4 kHz). Puis, le démasquage a été évalué en EEG par l’étude 1) des latences précoces (<10 ms, PEA-P), 2) des latences tardives (<50 ms, PEA-T) et 3) de l’onde de discordance (PEA-MMN). Pour ces trois études EEG, l’influence de la cohérence temporelle des bruits bilatéraux a été explorée.Résultats : L’étude perceptive traduit un démasquage croissant lorsque la largeur fréquentielle du bruit controlatéral augmente. L’ajout du bruit controlatéral non corrélé (corrélation=0) se traduit par une amélioration de détection de 1,28 dB, quelle que soit la fréquence des stimuli cibles (antimasquage), alors que l’ajout d’un bruit controlatéral corrélé (corrélation=1) évoque une amélioration de détection lorsque la fréquence des stimuli cibles diminue (démasquage) : 0,97 dB à 4 kHz et 9,25 dB à 0,5 kHz. En PEA-P, les latences des ondes III et V se raccourcissent lorsqu’un bruit controlatéral corrélé ou non corrélé est ajouté (≈0,1 ms). En PEA-T, les amplitudes des ondes P1, N1 et des complexes P1N1 et N1P2 augmentent lorsqu’un bruit controlatéral corrélé ou non corrélé est ajouté. Enfin, l’amplitude de la MMN est plus conséquente lorsque le bruit controlatéral ajouté est corrélé (versus non corrélé). Conclusion : L’étude perceptive explicite l’importance des indices spectraux (antimasquage) et temporels (démasquage), pour améliorer la perception d’un signal initialement masqué. L’étude EEG suggère, quant à elle, un traitement sous-cortical influencé uniquement par les indices spectraux (antimasquage) et un traitement plus cortical influencé par les indices temporels (démasquage). / Background: Binaural unmasking is an essential process for understanding in noisy environments. This mechanism would involve the comparison of time and frequency cues throughout the hearing nerve pathways. However, there is no real consensus evoking a treatment of a binaural masking release at a subcortical and/or a cortical level. The purpose of this study is to investigate the time and frequency cues of the binaural unmasking through a perceptual study, and then through an electroencephalographic study (EEG).Materials and Methods: Normal hearing people were evaluated with a perceptive study to estimate the importance of the binaural unmasking according to 1) the frequency width of the contralateral noise (1 octave, 3 octaves or broadband), 2) the temporal coherence of bilateral noises (correlation equal to 0 or 1) and 3) the frequency of the target stimuli (0.5, 1, 2 and 4 kHz). Binaural unmasking was then evaluated with EEG by studying 1) early latencies (<10 ms, PEA-P), 2) late latencies (<50 ms, PEA-T) and 3), the mismatch wave (PEA- MMN). For these three EEG studies, the influence of the temporal coherence of bilateral noise was investigated.Results: The study shows a growing perceptive binaural unmasking when the frequency width of the contralateral noise increases. The addition of an uncorrelated contralateral noise (correlation = 0) results in a 1.28 dB detection enhancement, regardless of the frequency of the target stimuli (antimasking), while adding a contralateral correlated noise (correlation = 1) refers to a detection enhancement when the frequency of the target stimuli decreases (unmasking): 0.97 dB at 4 kHz and 9.25 dB at 0.5 kHz. The latencies of waves III and V are shortened when a contralateral correlated or uncorrelated noise is added (≈0,1 ms) in the PEA-P. The amplitudes of P1, N1 waves and P1N1 and N1P2 complex increase when contralateral correlated or uncorrelated noise is added in PEA-T. Finally, the amplitude of the MMN is higher when a contralateral correlated noise is added (versus an uncorrelated one).Conclusion: The perceptual study shows the significance of spectral cues (antimasking) and temporal cues (unmasking), to improve the perception of an initially masked signal. The EEG study suggests a subcortical treatment which is only influenced by spectral cues (antimasking) and a cortical processing, influenced by temporal cues (unmasking).
102

The SCExAO high contrast imager: transitioning from commissioning to science

Jovanovic, N., Guyon, O., Lozi, J., Currie, T., Hagelberg, J., Norris, B., Singh, G., Pathak, P., Doughty, D., Goebel, S., Males, J., Kuhn, J., Serabyn, E., Tuthill, P., Schworer, G., Martinache, F., Kudo, T., Kawahara, H., Kotani, T., Ireland, M., Feger, T., Rains, A., Bento, J., Schwab, C., Coutts, D., Cvetojevic, N., Gross, S., Arriola, A., Lagadec, T., Kasdin, J., Groff, T., Mazin, B., Minowa, Y., Takato, N., Tamura, M., Takami, H., Hayashi, M. 26 July 2016 (has links)
SCExAO is the premier high-contrast imaging platform for the Subaru Telescope. It offers high Strehl ratios at near-IR wavelengths (y-K band) with stable pointing and coronagraphs with extremely small inner working angles, optimized for imaging faint companions very close to the host. In the visible, it has several interferometric imagers which offer polarimetric and spectroscopic capabilities. A recent addition is the RHEA spectrograph enabling spatially resolved high resolution spectroscopy of the surfaces of giant stars, for example. New capabilities on the horizon include post-coronagraphic spectroscopy, spectral differential imaging, nulling interferometry as well as an integral field spectrograph and an MKID array. Here we present the new modules of SCExAO, give an overview of the current commissioning status of each of the modules and present preliminary results.
103

Desenvolvimento e controle de qualidade de micropartículas poliméricas contendo praziquantel para o tratamento pediátrico da esquistossomose

Machado, Jaison Carlosso January 2016 (has links)
A esquistossomose é uma doença parasitária aguda e crônica causada por vermes sanguíneos (vermes nematoides) do gênero Schistosoma. O homem contrai a esquistossomose através da penetração ativa da cercaria na pele. A importância do tratamento desta enfermidade consiste não só no fato de curar a doença ou diminuir a carga parasitária dos pacientes, bem como impedir sua evolução para formas mais graves. Para o tratamento da esquistossomose o fármaco de escolha é o praziquantel; isso se deve ao seu amplo espectro, sua eficácia, segurança e a relação custo/tratamento. A única forma farmacêutica disponível no Brasil é o comprimido, na dose de 600 mg, a qual pode ser subdividida em quatro partes de 150 mg, a fim de facilitar o ajuste de dose. No entanto, no momento da subdivisão dos comprimidos ocorre o rompimento do revestimento. Este fato acaba levando a uma exposição do fármaco e, consequentemente, de seu sabor amargo. Esta característica dificulta a administração do medicamento, principalmente na população infantil, prejudicando o tratamento e o controle da doença. Uma alternativa para este problema é o desenvolvimento de sistemas poliméricos microparticulados que associados ao fármaco impediriam o contato direto com as papilas gustativas e assim promoveriam uma melhoria na palatabilidade. Para isso utilizou-se a técnica modificada de deposição interfacial do polímero pré-formado seguido de secagem por aspersão. Três matrizes poliméricas, com diferentes características de liberação foram utilizadas, Eudragit RL 100 – liberação tempo dependente e Eudragit E100 e L30D-55 – liberação pH dependente. Além disso, dois tipos de sistemas carreadores do fármaco foram preparados, microcápsulas e microesferas poliméricas. Estes sistemas obtidos foram avaliados e caracterizados a fim de eleger a melhor proposta de formulação visando o mascaramento do sabor do fármaco. De acordo com os resultados obtidos selecionou-se um sistema composto por microcápsulas formadas a partir do polímero L30D-55. A partir de então inseriu-se este sistema na forma farmacêutica pó para suspensão oral, onde diferentes propostas de formulações, contendo dois edulcorantes auxiliares, aspartame e sacarina, separadamente, e seus respectivos placebos foram avaliadas através de um método in vitro para a determinação do sabor, a língua eletrônica ou sensor gustativo. As diferentes formulações avaliadas apresentaram capacidade em mascarar o sabor desagradável do fármaco e, assim resultam em uma promissora alternativa para o aumento da adesão por parte dos pacientes à terapêutica, principalmente para crianças, em virtude da facilidade de administração, do ajuste da dose em função da massa corpórea e ao sabor muito mais agradável ao paladar infantil. / Schistosomiasis is a parasitic disease acute and chronic caused by blood worms (nematodes worms) of the genus Schistosoma. Man acquires schistosomiasis through the active penetration of the worms in skin. The importance of treatment of this disease is not only the fact of curing the disease or decreases the parasite load of patients, well as prevent progression to more severe forms. For the treatment of schistosomiasis praziquantel is the drug of choice, this is due to its wide spectrum, its efficacy, safety and the relation cost / treatment. The single dosage form available in Brazil is tablet at a dose of 600 mg, which can be subdivided into four parts of 150 mg to facilitate dose adjustment. However when the subdivision of the tablets occurs the disruption of the coating. This fact provides a drug exposure and consequently of its bitter taste. This characteristic complicates the administration of the drug mainly in children, affecting the treatment and control of disease. An alternative for this problem is the development of microparticulate polymeric systems which associated with the drug would prevent direct contact with the taste buds and thus promote an improvement in palatability. For this was used a modified technique interfacial deposition of preformed polymer followed by spray drying. Three polymer matrices with different release characteristics have been used, Eudragit RL 100 – time dependent release, and Eudragit E100 and L30D-55 – pH dependent release. Furthermore, two types of drug carrier systems have been prepared, polymeric microspheres and microcapsules. These systems obtained were evaluated and characterized in order to select the best proposal formulation aimed at masking the taste of the drug. According to the results we selected a system comprising microcapsules formed from L30D-55 polymer. From then was inserted into this system in the pharmaceutical form, powder for oral suspension, where different proposals formulations containing two auxiliary sweeteners, aspartame and saccharin, separately, and their respective placebos were evaluated in an in vitro method for determining the taste, the electronic tongue. The different formulations tested presented excellent ability to mask the unpleasant taste of the drug and thus present an excellent alternative for increasing adherence to therapy, especially for children, because of the ease of administration, according on dose adjustment of body mass and the much more palatable to children's taste.
104

Cephalometric analysis of adolescents with severe Class II Division 1 malocclusions treated surgically and non-surgically

Brady, Patrick 01 May 2016 (has links)
Introduction: Class II Division 1 malocclusions are characterized by a retrusive mandible and prominent upper incisors. Despite Class II malocclusions being one of the most frequently treated cases in orthodontists' office, there is no uniform consensus in the orthodontic community on the best treatment modality and biomechanical approach to use in treating patients with Class II malocclusions. Purpose: This paper examines the end-of-treatment outcomes of severe Class II Division I malocclusion patients treated with surgical versus non-surgical approaches. Study Design: This is a retrospective study of consecutively treated severe Class II Division I patients at the University of Iowa. Initial and deband lateral cephalometric radiographs were compared between 45 non-surgical and 21 surgical patients. All patients that were debanded between the ages of 13 to 19 years were included. Multivariable regression analyses were used to examine differences in outcomes between treatment groups. Results: Following adjustment for patient level confounders (age, gender, and race), those treated surgically had better end of treatment cephalometric outcomes. Those treated surgically had a more balanced skeletal profile, greater reduction in overjet, and improvement in ANB angle (p Conclusion: Orthodontic treatment in conjunction with orthognathic surgery is a more ideal treatment for patients with severe Class II Division I malocclusion. When treated surgically, a greater amount of overjet can be reduced while keeping lower incisors in a more stable position in bone.
105

Contre-mesures aux attaques par canaux cachés et calcul multi-parti sécurisé / Countermeasures to side-channel attacks and secure multi-party computation

Thillard, Adrian 12 December 2016 (has links)
Les cryptosystèmes sont présents dans de nombreux appareils utilisés dans la vie courante, tels que les cartes à puces, ordiphones, ou passeports. La sécurité de ces appareils est menacée par les attaques par canaux auxiliaires, où un attaquant observe leur comportement physique pour obtenir de l’information sur les secrets manipulés. L’évaluation de la résilience de ces produits contre de telles attaques est obligatoire afin de s’assurer la robustesse de la cryptographie embarquée. Dans cette thèse, nous exhibons une méthodologie pour évaluer efficacement le taux de succès d’attaques par canaux auxiliaires, sans avoirbesoin de les réaliser en pratique. En particulier, nous étendons les résultats obtenus par Rivain en 2009, et nous exhibons des formules permettant de calculer précisément le taux de succès d’attaques d’ordre supérieur. Cette approche permet une estimation rapide de la probabilité de succès de telles attaques. Puis, nous étudions pour la première fois depuis le papier séminal de Ishai, Sahai et Wagner en 2003 le problème de la quantité d’aléa nécessaire dans la réalisation sécurisée d’une multiplication de deux bits. Nous fournissons des constructions explicites pour des ordres pratiques de masquage, et prouvons leur sécurité et optimalité. Finalement, nous proposons un protocole permettant le calcul sécurisé d’un veto parmi un nombre de joueurs arbitrairement grand, tout en maintenant un nombre constant de bits aléatoires. Notre construction permet également la multiplication sécurisée de n’importe quel nombre d’éléments d’un corps fini. / Cryptosystems are present in a lot of everyday life devices, such as smart cards, smartphones, set-topboxes or passports. The security of these devices is threatened by side-channel attacks, where an attacker observes their physical behavior to learn information about the manipulated secrets. The evaluation of the resilience of products against such attacks is mandatory to ensure the robustness of the embedded cryptography. In this thesis, we exhibit a methodology to efficiently evaluate the success rate of side-channel attacks, without the need to actually perform them. In particular, we build upon a paper written by Rivainin 2009, and exhibit explicit formulaes allowing to accurately compute the success rate of high-order side-channel attacks. We compare this theoretical approach against practical experiments. This approach allows for a quick assessment of the probability of success of any attack based on an additive distinguisher. We then tackle the issue of countermeasures against side- channel attacks. To the best of our knowledge, we study for the first time since the seminal paper of Ishai, Sahai and Wagner in 2003 the issue of the amount of randomness in those countermeasures. We improve the state of the art constructions and show several constructions and bounds on the number of random bits needed to securely perform the multiplication of two bits. We provide specific constructions for practical orders of masking, and prove their security and optimality. Finally, we propose a protocolallowing for the private computation of a secure veto among an arbitrary large number of players, while using a constant number of random bits. Our construction also allows for the secure multiplication of any number of elements of a finite field.
106

Evaluating Public Masking Mandates on COVID-19 Growth Rates in U.S. States

Wong, Angus K 01 July 2021 (has links)
U.S. state governments have implemented numerous policies to help mitigate the spread of COVID-19. While there is strong biological evidence supporting the wearing of face masks or coverings in public spaces, the impact of public masking policies remains unclear. We aimed to evaluate how early versus delayed implementation of state-level public masking orders impacted subsequent COVID-19 growth rates. We defined “early” implementation as having a state-level mandate in place before September 1, 2020, the approximate start of the school-year. We defined COVID-19 growth rates as the relative increase in confirmed cases 7, 14, 21, 30, 45, 60-days after September 1. Primary analyses used targeted maximum likelihood estimation (TMLE) with Super Learner and considered a wide range of potential confounders to account for differences between states. In secondary analyses, we took an unadjusted approach and calculated the average COVID-19 growth rate among early-implementing states divided by the average COVID-19 growth rate among late-implementing states. At a national level, the expected growth rate after 14-days was 4%lower with early vs. delayed implementation (aRR: 0.96; 95%CI: 0.95-0.98). Associations did not plateau over time, but instead grew linearly. After 60-days, the expected growth rate was 16% lower with early vs. delayed implementation (aRR:0.84; 95%CI: 0.78-0.91). Unadjusted estimates were exaggerated (e.g. 60-day RR:0.72; 95%CI: 0.60-0.84). Sensitivity analyses varying the timing of the masking order yielded similar results. In both the short and long term, state-level public masking mandates were associated with lower COVID-19 growth rates. Given their low-cost and minimal (if any) impact on the economy, masking policies are promising public health strategies to mitigate further spread of COVID-19.
107

Human Machine Interfacing With A Variable Speed Treadmill During Sensory Perturbation

Lundell, Sydney M. 09 August 2021 (has links)
No description available.
108

Normal Masking Level Difference Parameters For Use in the Clinical Evaluation of Auditory Processing Disorders

Burnham, Maria Noelle 29 June 2010 (has links)
Masking Level Difference (MLD) tests are an established component of auditory processing test batteries; however, normative data for these tests vary according to procedure. In this study, forty normal, native-English speaking adults between the ages of 18 and 26 were tested for MLD via a newly developed computer software program using both an adaptive procedure (MLDA) and a Bekesy procedure (MLDB). The results from the two procedures were analyzed for sex differences and compared with each other. For both the MLDA and MLDB, the results showed statistically significant sex differences in the masked thresholds used to obtain the MLD (NoSo and NoSπ), but no significant difference in the calculated MLD value (NoSo - NoSπ). These results suggest that since the MLD was similar for both sexes, the normative data need not be reported separately by sex. The results also showed statistically significant differences between procedures, with the MLDA procedure producing higher MLDs than the MLDB procedure. The MLDA procedure lent itself to a d´ analysis, which could not be determined using MLDB due to the nature of a Bekesy assessment. For MLDA, d´ = 1.4, test sensitivity = 96.4%, and test specificity = 60.3%. The results of this study indicate that MLDA is a better testing procedure due to MLDA's higher MLD average and the statistical data available (d´, and measures of sensitivity and specificity) when using the MLDA procedure.
109

Aplikace pro měření prahu slyšení a maskovacích křivek / Application for Measurement of Threshold in Quiet and Masking Curves

Bednář, Jan January 2015 (has links)
Main aim of this thesis is to create an application for measuring threshold in quiet and masking curves in C++ language. First chapter describes basic teory of perceiving sound and phenomenon of masking. Second chapter focuses on description of different hearing measurement methods. Third chapter describes, how the classes and functions for frequency changing oscilator and evaluation were created and how the graph display function works. Next chapter describes, how to use the application properly and how to do the basic calibration, so the data will be displayed correctly. Last chapter shows the correct function, measured thresholds in quiet and masking curves for two subjects.
110

Návrh a realizace systému pro maskování výpadku dispečerského PC zálohováním dat získaných z váhy TAMRON / Design and Realization of a System for Masking Dispatcher PC Cut-Off by Backing-Up Data Obtained from TAMRON Weighing-Machine

Štulír, Vojtěch January 2010 (has links)
In the productive operation any kind of plant is undesirable due to failure of system that all production has been stopped. Therefore, different security and backup devices that covered those failures are being developed and used.   This thesis describes vulnerabilities in the real operation which are important for treatment and reduce the risk of failure in the whole production. Here is analyzed problem dispatching computer failure and its solution using a module for covering failure. The function of module consists in backup during failure, their sending and treating them after system failure removal.  Gradually described, there is an analysis of the system and place the module into their architecture. After all details follow description of module development from design through implementation to deployment and testing in reality.

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