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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.
1221

Influência da inclinação do garfo de mordida do arco facial na montagem do modelo superior em articulador semi-ajustável do tipo arcon e não-arcon / Influence of the inclination of the face-bow\'s bite fork on mounting of maxillary cast in arcon and nonarcon semiadjustable articulators

Daniele Manfrim Bellodi 15 August 2008 (has links)
Durante o processo ensino/aprendizagem em Odontologia, é comum a ocorrência de inclinações do garfo de mordida em relação ao plano oclusal maxilar dos pacientes durante a tomada do arco facial realizada por alunos. Este trabalho avaliou a influência das inclinações do garfo de mordida para anterior e para posterior em relação ao plano oclusal na montagem do modelo maxilar em articuladores semi-ajustáveis do tipo arcon e não-arcon. Foram obtidos vinte modelos do arco maxilar de vinte pacientes, nos quais dois pontos foram marcados: um na aresta vestibular do canino direito e outro na aresta vestibular da cúspide mésio-vestibular do primeiro molar direito. Os registros no garfo de mordida foram realizados em três posições: garfo de mordida paralelo ao plano oclusal dos modelos, inclinado para anterior e para posterior (ambas 5º). Cada posição foi repetida cinco vezes, sendo o conjunto articulador/arco facial fixado em suporte especial para registro fotográfico. Cada fotografia foi levada ao programa Auto CAD, obtendo-se linhas de referências para a coleta de cinco medidas (uma angular e quatro lineares). Os dados obtidos foram submetidos à análise estatística paramétrica (Análise de Variância). Os resultados indicaram não haver diferença estatisticamente significante para inclinações do garfo de mordida tanto para anterior como para posterior em relação ao plano oclusal do modelo tanto para o articulador semi-ajustável do tipo arcon como para o não-arcon. O trabalho sugere que pequenas inclinações do garfo de mordida não comprometem a tomada do arco facial e sua transferência para articuladores semi-ajustáveis. / During the process teaching/learning in Dentistry, the occurrence of adverse inclinations of the bite fork concerned to maxillary occlusal plane of patients are current during the face-bow taking performed by students. This study evaluated the influence of the inclinations of bite fork to anterior and posterior related to oclusal plane on mounting of the maxillary cast in arcon and nonarcon semiadjustable articulators. Twenty casts of the maxillary arch from twenty patients were obtained, on which two points were marked: one on the vestibular edge of the right canine and another on the vestibular edge of mesiovestibular cusp of the right first molar. The records in the bite fork were made in three positions: the bite fork parallel to the castss plane occlusal, inclined to anterior and to posterior (both 5°). Each position was repeated five times, being the articulator/face-bow set fixed in special support for photographic register. Each photograph was introduced in Auto CAD program, resulting in lines of references for the collection of five measures (one angular and four linear). The data were subjected to statistical analysis parametric (Analysis of Variance). The results showed no significant statistical difference for inclinations of the bite fork to both anterior and to posterior related to the castss occlusal plane for the arcon and nonarcon semiadjustable articulators. The work suggests that small inclinations of bite fork do not compromise the face-bow taking and its transfer for the semiadjustable articulators.
1222

Reconhecimento de faces com filtragens de frequências espaciais altas e baixas nos hemicampos visuais direito e esquerdo / Facial recognition in high and low spatial frequency filtering in the right and in the left hemifields

Moraes Júnior, Rui de 06 March 2012 (has links)
O presente estudo teve por objetivo investigar se o reconhecimento de faces ocorre prioritariamente por processamento analítico ou holístico nos hemisférios cerebrais em homens e mulheres por meio do estudo do espectro de frequência espacial. Para isso, no Experimento I, 40 voluntários (20 mulheres) realizaram duas sessões. Em cada uma delas foram memorizadas 14 faces para uma tarefa de reconhecimento. Nesta, cada face foi apresentada por 300 ms, e em uma das sessões as imagens foram apresentadas somente no hemicampo visual direito, e noutra só no hemicampo visual esquerdo por meio de uma adaptação do método do campo visual dividido. A tarefa dos participantes foi assinalar o grau de confiabilidade de sua resposta (confidence rating method) ao discriminar as faces memorizadas de outras inéditas. Os estímulos da tarefa de reconhecimento foram apresentados em três condições: (1) em frequências espaciais altas, FEAs, (2) em frequências espaciais baixas, FEBs, e (3) sem filtragem, SFE. As frequências de respostas aos graus de confiabilidade permitiram calcular as curvas ROC e os parâmetros Az e da da Teoria de Deteção de Sinal. Por meio destes, foi comparado o desempenho do reconhecimento facial nas diferentes faixas do espectro espacial. De maneira complementar, foi realizado uma ANOVA para testar a diferença dos tempos de resposta no reconhecimento entre as filtragens. Não foi evidenciada especialização hemisférica no reconhecimento de faces com filtragem espacial. Mas homens, de modo tênue, perceberam melhor faces em FEBs e mulheres em FEAs. Para verificar se este resultado não se deu em função da apresentação lateralizada, foi realizado o Experimento II, nos moldes de uma sessão experimental do Experimento I, mas com apresentação central. Vinte voluntários (10 mulheres) participaram do experimento. Novamente, homens e mulheres foram mais sensíveis às faces em FEBs e FEAs, respectivamente. Deste modo, conclui-se que homens utilizam mais recursos holísticos e mulheres, por sua vez, operações analíticas. Os resultados dão bases para a não ocorrência de especialização hemisférica de frequencias espaciais no reconhecimento de faces em longos tempos de exposições. A diferença de sexo observada e nos atenta para a necessidade de controle amostral por sexo em pesquisas da área. / This study aimed to investigate whether face recognition occurs primarily by analytic or holistic processing in the cerebral hemispheres of men and women through the study of the spatial frequency spectrum. Therefore, in Experiment I, 40 volunteers (20 women) performed two sessions. In each of, 14 faces were memorized for a recognition task and each face was presented for 300 ms. Images were presented only in the right visual hemifield in a session, and in another only in the left visual hemifield by means of an adaptation of the method of divided visual field. The participants task was to assign the reliability of their response (confidence rating method) to discriminate the study faces from distractors. The recognition task stimuli were presented in three conditions: (1) at high spatial frequencies, FEAs, (2) at low spatial frequencies, FEBs, and (3) unfiltered, SFE. The frequencies of responses to the degree of reliability used to calculate ROC curves and parameters Az and da of the Signal Detection Theory compared the performance of face recognition in different bands of the spectrum. In a complementary way, an ANOVA was conducted to test response times differences in the recognition between filtering. There was no evidence of hemispheric specialization in face recognition with spatial filtering. But men had better performance in recognizing faces in FEBs and women faces in FEAs. To verify that this result was not in function of lateralized presentation, Experiment II was conducted, along the lines of an experimental session of Experiment I, but with central presentation. Twenty volunteers (10 women) participated in the experiment. Again, men and women were more sensitive to faces in FEBs and FEAs, respectively. Thus it follows that men use holistic resources and women analytical operations. The results provide no basis for the occurrence of hemispheric specialization of spatial frequencies in face recognition over long exposure times. The sex difference observed brings us to the need for control sample by sex in spatial frequency research.
1223

Functional and Stylistic Features of Sports Announcer Talk: A Discourse Analysis of the Register of Major League Soccer Television Broadcasts

Balzer-Siber, Marco 01 May 2015 (has links)
This study analyzes the register of television sports announcers in Major League Soccer broadcasts, based on six 20-minute transcription samples. The first part considers individual linguistic features and inquires whether they fulfill a communicative function or whether they are of stylistic nature. In an effort to attract more viewers in the United States, production companies had originally adopted the duality model of a play-by-play announcer and a color commentary from other American sports, while many other countries traditionally feature only one commentator. Consequently, the second part of this discourse analysis will focus on the cooperative interactional behavior. The conclusion will be drawn that the register of live action announcing, in contrast to halftime as well as pre- and post-game reporting, is based on cooperative principles. Moreover, both the individual and the collaborative linguistic variables mostly reflect an effort to protect one’s own and the colleague’s public image.
1224

Sex-Specific Scanning in Infancy: Developmental Changes in the Use of Face/Head and Body Information

White, Hannah, Jubran, Rachel, Heck, Alison, Chroust, Alyson, Bhatt, Ramesh S. 01 June 2019 (has links)
The current investigation sought to differentiate between contrasting perspectives of body knowledge development by determining whether infants’ adult-like scanning of male and female bodies is dependent on relevant information from the face/head alone, the body alone, or a combination of both sources. Scanning patterns of 3.5-, 6.5-, and 9-month-olds (N = 80) in response to images that contained information relevant to sex classification in either the face/head or the body were examined. The results indicate that sex-specific scanning in the presence of only one source of relevant information (i.e., face/head or body) is present only at 9 months. Thus, although sex-specific scanning of bodies emerges as early as 3.5 months, information from both faces/heads and bodies is required until sometime between 6.5 and 9 months of age. These findings constrain theories of the development of social perception by documenting the complex interplay between body and face/head processing early in life
1225

Emotion Discrimination in Peripheral Vision

Lambert, Hayley M 01 April 2018 (has links)
The recognition accuracy of emotion in faces varies depending on the discrete emotion being expressed and the location of the stimulus. More specifically, emotion detection performance declines as facial stimuli are presented further out in the periphery. Interestingly, this is not always true for faces depicting happy emotional expressions, which can be associated with maintained levels of detection. The current study examined neurophysiological responses to emotional face discrimination in the periphery. Two event-related potentials (ERPs) that can be sensitive to the perception of emotion in faces, P1 and N170, were examined using EEG data recorded from electrodes at occipitotemporal sites on the scalp. Participants saw a face presented at a 0° angle of eccentricity, at a 10° angle of eccentricity, or at a 20° angle of eccentricity, and responded whether the face was a specific emotion or neutral. Results showed that emotion detection was higher when faces were presented at the center of the display than at 10° or 20° for both happy and angry expressions. Likewise, the voltage amplitude of the N170 component was greater when faces were presented at the center of the display than at 10° or 20°. Further exploration of the data revealed that high intensity expressions were more easily detected at each location and elicited a larger amplitude N170 than low intensity expressions for both emotions. For a peripheral emotion discrimination task like that which was employed in the current study, emotion cues seem to enhance face processing at peripheral locations.
1226

Spatial Augmented Reality Using Structured Light Illumination

Yu, Ying 01 January 2019 (has links)
Spatial augmented reality is a particular kind of augmented reality technique that uses projector to blend the real objects with virtual contents. Coincidentally, as a means of 3D shape measurement, structured light illumination makes use of projector as part of its system as well. It uses the projector to generate important clues to establish the correspondence between the 2D image coordinate system and the 3D world coordinate system. So it is appealing to build a system that can carry out the functionalities of both spatial augmented reality and structured light illumination. In this dissertation, we present all the hardware platforms we developed and their related applications in spatial augmented reality and structured light illumination. Firstly, it is a dual-projector structured light 3D scanning system that has two synchronized projectors operate simultaneously, consequently it outperforms the traditional structured light 3D scanning system which only include one projector in terms of the quality of 3D reconstructions. Secondly, we introduce a modified dual-projector structured light 3D scanning system aiming at detecting and solving the multi-path interference. Thirdly, we propose an augmented reality face paint system which detects human face in a scene and paints the face with any favorite colors by projection. Additionally, the system incorporates a second camera to realize the 3D space position tracking by exploiting the principle of structured light illumination. At last, a structured light 3D scanning system with its own built-in machine vision camera is presented as the future work. So far the standalone camera has been completed from the a bare CMOS sensor. With this customized camera, we can achieve high dynamic range imaging and better synchronization between the camera and projector. But the full-blown system that includes HDMI transmitter, structured light pattern generator and synchronization logic has yet to be done due to the lack of a well designed high speed PCB.
1227

INVESTIGATION OF AN AXIAL FLOW ROTARY VALVE SEAL

Stieha, Joseph K. 01 January 2017 (has links)
This thesis investigates potential materials to be used in the rotary sealing industry that provide low power loss and minimize cost. The studied rotary valve utilizes slots that act as timing valves to allow for flow axially, through the seal face, at particular times within a heat pump cycle. This investigation examines various combinations of multiple PTFE materials, plastics, and soft metals that have been proven to provide low friction coefficients. Leakage and wear requirements are stated for the future use of the rotary valve and are used to determine the effectiveness of sealing the fluid while examining the power loss. In conclusion, the study finds the combination of a modified PTFE stationary ring and Aluminum Bronze rotating face to provide the lowest power loss. Numerical analysis was completed to verify the lubrication regime to be partial lubrication and was also used to investigate geometry changes and impact on the power loss.
1228

Le développement de la perception des expressions faciales / The development of facial expressions perception

Bayet, Laurie 26 November 2015 (has links)
Cette thèse se propose d'examiner le développement de la perception des expressions faciales émotionnelles en le replaçant dans le cadre théorique de la perception des visages: séparation entre aspects variants (expression, regard) et invariants (genre, type), rôle de l'expérience, attention sociale. Plus spécifiquement, nous avons cherché à mettre en évidence l'existence, tant chez l'enfant que chez le nourrisson, d'interactions réciproques entre la perception d'expressions faciales de colère, de sourire ou de peur et la perception du genre (Études 1-2), la perception du regard (Étude 3), et la détection des visages (Étude 4).Dans un premier temps, nous avons montré que les adultes et les enfants de 5 à 12 ans tendent à catégoriser les visages en colère comme masculins (Étude 1). Comparer les performances humaines avec celles de classifieurs automatique suggère que ce biais reflète l'utilisation de certains traits et relations de second-ordre des visages pour en déterminer le genre. Le biais est identique à tous les âges étudiés ainsi que pour les visages de types non-familiers. Dans un second temps, nous avons testé si, chez le nourrisson, la perception du sourire dépend de dimensions invariantes du visage sensibles à l'expérience - le genre et le type (Étude 2). Les nourrissons ont généralement plus d'expérience avec les visages féminins d'un seul type. Les nourrissons de 3.5 mois montrent une préférence visuelle pour les visages souriants (dents visibles, versus neutre, de type familier) lorsque ceux-ci sont féminins; l'inverse est observé lorsqu'ils sont masculins. L'effet n'est pas répliqué lorsque les dents des visages souriants (d'un type familier ou non) ne sont pas visibles. Nous avons cherché à généraliser ces résultats à une tâche de référencement d'objet chez des nourrissons de 3.5, 9 et 12 mois (Étude 3). Les objets préalablement référencés par des visages souriants étaient autant regardés que les objets préalablement référencés par des visages neutres, quel que soit le groupe d'âge ou le genre du visage, et ce malgré des différences en terme de suivi du regard. Enfin, en employant une mesure univariée (préférence visuelle pour le visage) et une mesure multivariée (évidence globale distinguant le visage du bruit) de la détection du visage à chaque essai, associées à une modélisation des courbes psychométriques par modèles non-linéaire mixtes, nous mettons en évidence une meilleure détection des visages de peur (comparés aux visages souriants) dans le bruit phasique chez les nourrissons à 3.5, 6 et 12 mois (Étude 4).Ces résultats éclairent le développement précoce et le mécanisme des relations entre genre et émotion dans la perception des visages ainsi que de la sensibilité à la peur. / This thesis addressed the question of how the perception of emotional facial expressions develops, reframing it in the theoretical framework of face perception: the separation of variant (expression, gaze) and invariant (gender, race) streams, the role of experience, and social attention. More specifically, we investigated how in infants and children the perception of angry, smiling, or fearful facial expressions interacts with gender perception (Studies 1-2), gaze perception (Study 3), and face detection (Study 4).In a first study, we found that adults and 5-12 year-old children tend to categorize angry faces as male (Study 1). Comparing human performance with that of several automatic classifiers suggested that this reflects a strategy of using specific features and second-order relationships in the face to categorize gender. The bias was constant over all ages studied and extended to other-race faces, further suggesting that it doesn't require extensive experience. A second set of studies examined whether, in infants, the perception of smiling depends on experience-sensitive, invariant dimensions of the face such as gender and race (Study 2). Indeed, infants are typically most familiar with own-race female faces. The visual preference of 3.5 month-old infants for open-mouth, own-race smiling (versus neutral) faces was restricted to female faces and reversed in male faces. The effect did not replicate with own- or other-race closed-mouth smiles. We attempted to extend these results to an object-referencing task in 3.5-, 9- and 12-month-olds (Study 3). Objects previously referenced by smiling faces attracted similar attention as objects previously cued by neutral faces, regardless of age group and face gender, and despite differences in gaze following. Finally, we used univariate (face side preference) and multivariate (face versus noise side decoding evidence) trial-level measures of face detection, coupled with non-linear mixed modeling of psychometric curves, to reveal the detection advantage of fearful faces (compared to smiling faces) embedded in phase-scrambled noise in 3.5-, 6-, and 12-month-old infants (Study 4). The advantage was as or more evident in the youngest group than in the two older age groups.Taken together, these results provide insights into the early ontogeny and underlying cause of gender-emotion relationships in face perception and the sensitivity to fear.
1229

Statistický model tvaru obličeje / Statistical model of the face shape

Boková, Kateřina January 2019 (has links)
The goal of this thesis is to use machine learning methods for datasets of scanned faces and to create a program that allows to explore and edit faces represented as triangle meshes with a number of controls. Firstly we had to reduce dimension of triangle meshes by PCA and then we tried to predict shape of meshes according to physical properties like weight, height, age and BMI. The modeled faces can be used in animation or games.
1230

Trusting the Dating Partner in the Face of Relationship Problems and Uncertainty: The Moderating Role of Parents and Friends

Johnson, Rebecca 01 May 2006 (has links)
Using a sample of 82 college students in dating relationships, this study is an examination of the moderating effect of parents' and friends' approval of the dating relationship on the associations between participants' individual characteristics (age, self-esteem, and own agreeableness) and relationship characteristics (love, ambivalence, conflict, conflict resolution effectiveness, and perception of the partner's agreeableness) with trust. The results of the hierarchical regression analyses showed that approval of the relationship by parents and friends moderated the relationship between individual characteristics and relationship characteristics with trust. Specifically, friends' approval of the relationship moderated the association between self-esteem and age with trust, whereas parents' approval of the relationship moderated the association between love, conflict, ambivalence, and conflict resolution effectiveness, with trust. The findings contribute to research and theory on dyadic trust, uncertainty reduction, and social network approval.

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