Thesis (Ph. D. in Psychology)--Vanderbilt University, May 2009. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--Rochester Institute of Technology, 2010. / Typescript. Includes bibliographical references (leaves 72-77).

Thesis (Ph.D.)--York University, 2008. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 178-192). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR51690

Yes / Physical interactions between objects, or between an object and the ground, are amongst the most biologically relevant for live beings. Prior knowledge of Newtonian physics may play a role in disambiguating an object’s movement as well as foveation by increasing the spatial resolution of the visual input. Observers were shown a virtual 3D scene, representing an ambiguously rotating ball translating on the ground. The ball was perceived as rotating congruently with friction, but only when gaze was located at the point of contact. Inverting or even removing the visual context had little influence on congruent judgements compared with the effect of gaze. Counterintuitively, gaze at the point of contact determines the solution of perceptual ambiguity, but independently of visual context. We suggest this constitutes a frugal strategy, by which the brain infers dynamics locally when faced with a foveated input that is ambiguous. / J.S. was funded by a College of Life Sciences studentship from the University of Leicester.

La recherche présentée dans cette thèse est divisée en trois parties. Notre objectif dans la première partie est l’amélioration de la compression de l’image par stéganographie. Dans cette étude, la compression de données est effectuée en deux étapes. Tout d’abord, nous profitons du compactage d’énergie en utilisant JPEG pour réduire les données redondantes. Ensuite, nous intégrons des blocs de bits dans les blocs suivants de la même image stéganographie. Les bits intégrés servent à non seulement augmenter la taille du fichier de l’image compressée, mais aussi à diminuer davantage la taille du fichier. Les résultats expérimentaux montrent que notre méthode donne de meilleurs taux de compression tout en conservant une haute qualité de l’image. Le deuxième sujet de cette thèse propose un formalisme bayésien pour la stéganalyse d’image numérique qui permet la détection d’images stego, l’identification de l’algorithme de stéganographie utilisé, l’estimation de la longueur du message et l’emplacement, et l’anticipation dans le cas de l’intégration en utilisant un algorithme de stéganographie inconnu. La détection, l’identification et l’anticipation impliquent l’apprentissage discriminant dans l’espace des fonctions. L’estimation nécessite la fusion de classificateurs permettant la discrimination entre les sous-images et une intégration entière des couvertures de tailles différentes. La validation sur des images JPEG montre que le système proposé est efficace et permet d’anticiper des algorithmes de stéganographie inconnus. Le troisième sujet de la thèse décrit une méthode d’estimation du regard de l’oeil humain pendant un mouvement normal de la tête. Dans ce procédé, la position et l’orientation de la tête sont acquises par des données de profondeur fournies par Kinect. La direction de l’oeil est obtenue à partir d’images à haute résolution. Nous nous proposons la régression logistique multinomiale pour construire une fonction de mappage du regard et de vérifier l’état de l’iris. L’efficacité de la méthode proposée est validée par une évaluation de la performance pour plusieurs personnes avec différentes distances et poses par rapport à la caméra et dans différents états de l’oeil.

La recherche présentée dans cette thèse est divisée en trois parties. Notre objectif dans la première partie est l’amélioration de la compression de l’image par stéganographie. Dans cette étude, la compression de données est effectuée en deux étapes. Tout d’abord, nous profitons du compactage d’énergie en utilisant JPEG pour réduire les données redondantes. Ensuite, nous intégrons des blocs de bits dans les blocs suivants de la même image stéganographie. Les bits intégrés servent à non seulement augmenter la taille du fichier de l’image compressée, mais aussi à diminuer davantage la taille du fichier. Les résultats expérimentaux montrent que notre méthode donne de meilleurs taux de compression tout en conservant une haute qualité de l’image. Le deuxième sujet de cette thèse propose un formalisme bayésien pour la stéganalyse d’image numérique qui permet la détection d’images stego, l’identification de l’algorithme de stéganographie utilisé, l’estimation de la longueur du message et l’emplacement, et l’anticipation dans le cas de l’intégration en utilisant un algorithme de stéganographie inconnu. La détection, l’identification et l’anticipation impliquent l’apprentissage discriminant dans l’espace des fonctions. L’estimation nécessite la fusion de classificateurs permettant la discrimination entre les sous-images et une intégration entière des couvertures de tailles différentes. La validation sur des images JPEG montre que le système proposé est efficace et permet d’anticiper des algorithmes de stéganographie inconnus. Le troisième sujet de la thèse décrit une méthode d’estimation du regard de l’oeil humain pendant un mouvement normal de la tête. Dans ce procédé, la position et l’orientation de la tête sont acquises par des données de profondeur fournies par Kinect. La direction de l’oeil est obtenue à partir d’images à haute résolution. Nous nous proposons la régression logistique multinomiale pour construire une fonction de mappage du regard et de vérifier l’état de l’iris. L’efficacité de la méthode proposée est validée par une évaluation de la performance pour plusieurs personnes avec différentes distances et poses par rapport à la caméra et dans différents états de l’oeil.

<p>Future warfare concerns information superiority, i.e. supplying decisionmakers with better information than their opponents. Their decisions will be based on information from various sensors such as radars, UAVs, satellites, or any other object that can supply the decision makers with information. A system like this will make use of a huge amount of data, and the decisionmakers may not be able to handle all information that will be presented to them. Because of this, they might make decisions that are not optimal for the task.</p><p>To enhance tha capability in decision making, the national defence college will create an avatar which will be located in a 3D presentation device, called the Visioscope (tm). If the computer system detects that a person might have made an erroneous decision, the avatar will act and point out the error, i.e. there will be a dialog between the decision makers and the avatar. One important factor when humans communicate with each other is mutual eye gaze. If mutual eye gaze can occur between the users and the avatar, and if the avatar can behave like a human, the communication process will be improved and the users will make less errors.</p><p>This literature study aims to generate some ideas about how existing technology supports mutual eye gaze between the avatar and the users in the ROLF 2010 environment. The study partly concerns how a computer system can control an avatar so that it behaves like a human.</p>

Augmented Reality (AR) devices are set apart from other mobile devices by the immersive experience they offer. Specifically, head-mounted AR devices can accurately sense and understand their environment through an increasingly powerful array of sensors such as cameras, depth sensors, eye gaze trackers, microphones, and inertial sensors. The ability of these devices to collect this information presents both challenges and opportunities to improve existing security and privacy techniques in this domain. Specifically, eye gaze tracking is a ready-made capability to analyze user intent, emotions, and vulnerability, and as an input mechanism. However, modern AR devices lack systems to address their unique security and privacy issues. Problems such as lacking local pairing mechanisms usable while immersed in AR environments, bystander privacy protections, and the increased vulnerability to shoulder surfing while wearing AR devices all lack viable solutions. In this dissertation, I explore how readily available eye gaze sensor data can be used to improve existing methods for assuring information security and protecting the privacy of those near the device. My research has presented three new systems, BystandAR, ShouldAR, and GazePair that each leverage user eye gaze to improve security and privacy expectations in or with Augmented Reality. As these devices grow in power and number, such solutions are necessary to prevent perception failures that hindered earlier devices. The work in this dissertation is presented in the hope that these solutions can improve and expedite the adoption of these powerful and useful devices. / Doctor of Philosophy / Augmented Reality (AR) devices are set apart from other mobile devices by the immersive experience they offer. The ability of these devices to collect information presents challenges and opportunities to improve existing security and privacy techniques in this domain. In this dissertation, I explore how readily available eye gaze sensor data can be used to improve existing methods for assuring security and protecting the privacy of those near the device. My research has presented three new systems, BystandAR, ShouldAR, and GazePair that each leverage user eye gaze to improve security and privacy expectations in or with Augmented Reality. As these devices grow in power and number, such solutions are necessary to prevent perception failures that hindered earlier devices. The work in this dissertation is presented in the hope that these solutions can improve and expedite the adoption of these powerful and useful devices.

Spontaneous speech is replete with disfluencies: pauses, hesitations, restarts, and less than ideal deliveries of information. Disfluency is a topic of interdisciplinary research with insights from psycholinguistics, phonetics and speech technology. Researchers have tried to determine: When does disfluency occur?, Can disfluency be reliably predicted to occur?, and ultimately, Why does disfluency occur? The focus of my thesis will be to address the question of why disfluency occurs by reporting the results of analyses of disfluency frequency and the relationship between disfluency and eye gaze in a collaborative dialogue. Psycholinguistic studies of disfluency and collaborative dialogue differ on their answers to why disfluency occurs and its role in dialogue. One hypothesis, which I will refer to as Strategic Modelling, suggests that disfluencies are designed by the speaker. According to the alternative view, which I will call the Cognitive Burden View, disfluency is the result of an overburdened language production system. Throughout this thesis, I will contrast these two theories for an ultimate answer to why disfluency occurs. Each hypothesis attaches a functional role to a structural definition of disfluency and therefore in order to determine why disfluency occurs, I will contrast the structural and functional characteristics of disfluency. I will attempt to do this by analysing the dialogue behaviour in terms of speech goals and eye gaze behaviour a speaker is engaged in when they make certain types of disfluencies. A multi-modal Map Task paradigm was used in this thesis, in which speakers were asked to describe the route on a cartoon map to a distant confederate listener who provided either visual or verbal feedback. Speakers were eye-tracked during the dialogue and a record was kept of when the speaker attended to the listener’s visual feedback. Experiment 1 tested the visual feedback paradigm to establish its validity as a baseline condition. Speakers were found to make more disfluencies when they could interact with the visual feedback, suggesting disfluency is more common in interactive circumstances. Experiment 2 added verbal feedback to the experimental paradigm to test whether listeners react differently to the two modalities of feedback. Speakers made more disfluencies when the feedback was more complicated. Structural disfluency types were also observed to fulfil different functions. Finally, Experiment 3 manipulated the motivation of the speaker and found that Motivated speakers gazed more often and were more disfluent per opportunity than Control speakers suggesting that highly motivated subjects are more willing to engage in difficult tasks.

This thesis describes a research study in the field of Human-Computer Interaction (HCI), specifically usability evaluation. The research investigated ways to optimise the usability of Web sites. It specifically compared Flash and HTML versions of several different types of Web sites. The study commenced with a literature review regarding the process of usability evaluation of Web sites. Various usability evaluation methods and techniques were explored, and two emerging techniques were chosen for further investigation: (1) a contingent heuristic approach; and (2) eye gaze tracking. In order to confirm that these two techniques can be used effectively for Web site usability evaluations, two experiments were conducted to evaluate the usability of Web sites. The first experiment utilised an online questionnaire derived from the Website Usability Contingent Evaluation Tool (WUCET), which was based on the contingent heuristic approach. The second experiment involved eye gaze tracking with the faceLAB system, while participants interacted with Web sites of different types. Both experiments utilised Flash and HTML versions of the same set of Web sites. By analysing data collected from the experiments, comparisons between the usability of Flash and HTML versions were made. The results from quantitative and qualitative analyses of survey responses suggested that Flash version of Web sites, in general, provided higher usability than HTML version of Web sites, but eye gaze tracking data analyses showed no significant difference between the two versions. However, analyses of the eye tracking data were useful for improving understanding of the ways in which users interact with different versions of the Web sites. In addition, other influential factors that could affect the perceived usability of the Web sites, such as user’s gender and previous experience with computers and the Web, were also considered. The results of the experiments showed that in regard to Flash and HTML implementations of Web sites, there was a difference in Web site usability perception patterns between male and female users, and also between users with long-term computer/Web experience and users with short-term experience. In addition, a range of different types (purposes) of Web sites were utilised. In this study, selected Web sites fall into three broad categories according to their main purpose: (1) information; (2) entertainment; and (3) e-commerce. It was discovered that the type of Web sites also influenced the usability of Flash and HTML versions of Web sites, as perceived by users.