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Dissertations / Theses on the topic 'Perceptual science'
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Secchia, Adrian. "Perceptual refinement for hierarchical radiosity." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/6439.
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Bibliography : p. 90-93.<br>This dissertation explores the use of a simple model of the human visual system to yield a performance improvement with hierarchical radiosity. Hierarchical radiosity is a physically based rendering algorithm and hence makes no attempt to optimize computation for human perception. We used a model of the edge enhancement properties of the human visual system to produce a perceptually based refinement oracle for the hierarchical radiosity algorithm. Tests of the perceptual oracle shows that it allows the hierarchical radiosity algorithm to produce the same visual quality output in half the time and using half the memory compared to the same algorithm using the standard refinement oracle.
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Horswill, Ian Douglas. "Specialization of perceptual processes." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12729.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.<br>Includes bibliographical references (leaves 152-161).<br>by Ian D. Horswill.<br>Ph.D.
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Savadjiev, Peter. "Perceptual organisation in diffusion MRI: curves and streamline flows." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32390.
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This thesis proposes a new computational framework for the modeling of biological tissue structure in diffusion MRI data. By measuring the local Brownian motion of water molecules, diffusion MRI provides estimates of local fibre orientations in tissues such as the white matter of the brain. Over the last years, diffusion MRI has become an important tool for the in vivo study of brain connectivity. Nevertheless, the inference of the structure of white matter fibres is still an open problem. The methodology introduced in this thesis is based on differential geometry and perceptual organisation. The key ideas are to model white matter fibres as 3D space curves, to view diffusion MRI data as providing information about the tangent vectors of these curves, and to frame the problem as that of inferring 3D curve geometry from a discretized, incomplete, and potentially blurred and noisy field of tangent measurements. Inspired by notions used in perceptual organisation in computer vision, we develop local geometric constraints which guide the inference process and ultimately result in the recovery of the underlying fibre geometry. We start by introducing a notion of co-helicity between triplets of orientation estimates, which is incorporated in a geometric inference process. This process is referred to as 3D curve inference, and it estimates the parameters of the local best-fit osculating helix for each orientation in the dataset. Based on this, a relaxation labeling framework is set-up for the regularization of diffusion MRI data. We then develop a 3D curve inference technique for the identification of complex sub-voxel fibre configurations in high angular resolution diffusion<br>Cette thèse présente une méthodologie pour la modélisation de la structure de tissus biologiques à partir de données d'imagerie par résonance magnetique (IRM) de diffusion. En mesurant le mouvement Brownien des molécules d'eau, l'IRM de diffusion permet d'estimer localement les orientations des fibres de matière blanche dans le cerveau. L'IRM de diffusion est un outil important pour l'étude in vivo de la connectivité du cerveau. Cependant, l'inférence de la structure des fibres de matière blanche demeure un problème en grande partie irrésolu. La méthodologie présentée dans cette thèse est basée sur la géométrie différentielle ainsi que sur l'organisation perceptuelle. Étant donné que les fibres de matière blanche peuvent être représentées par des courbes en 3D, et que l'IRM de diffusion donne des mesures reliées aux vecteurs tangents de ces courbes, le problème de base consiste à faire l'inférence de la géométrie de courbes en 3D, à partir de mesures de vecteurs tangents qui sont discretisées, incomplètes, et qui peuvent aussi être floues et bruitées. En se basant sur des notions empruntées à l'organisation perceptuelle en vision par ordinateur, nous développons des contraintes géométriques locales qui guident le processus d'inférence et dont le résultat ultime est la reconstruction de la géométrie des fibres sous-jacentes. Nous débutons par l'introduction d'une notion de co-hélicité entre des triplets d'estimés d'orientation, qui est incorporée dans un processus d'inférence géométrique. Cette méthode est appelée "3D curve inference" (inférence de courbes en 3D), et elle estime les paramètres de l'hélice osculatrice
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WONG, Hon Yui Eric. "Sino-American strategic relations : a perceptual-psychological approach." Digital Commons @ Lingnan University, 2002. https://commons.ln.edu.hk/pol_etd/8.
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The rise of China’s economic power and the end of US-Soviet rivalry has highlighted the importance of overall Sino-US relations and has made Sino-US interrelations in terms of security become more sophisticated and complicated. Although there obviously exist a number of issues in the Sino-US strategic relationship, my research takes two case studies for particular analysis. One issue, missile defense (MD), started during the presidency of Bill Clinton, but because of George W. Bush’s tough approach to China has become a critical issue in current Sino-US relations.
The Taiwan issue is another crucial case study in my research. Because of limitations of time and length, I will concentrate my analysis on the run-up to the Taiwan straits mini-crisis in 1996 in which intensive interactions and changes in the foreign policies of both sides can be observed. By analyzing these two cases, more can be known about the complex nature of the contemporary Sino-US relationship.
The psychological-perceptual approach, which borrows theories and concepts from psychology, has been one of the enduring and influential approaches in studying international relations. However, it is a new perspective for discussing the missile defense issue and the Taiwan crisis in 1996.
The circular flow of how the stimulus from the United States affects the perception of China, then its attendant foreign policies towards the United States, which in turn affects the perception of the United States and its consequent foreign policy towards China on both the MD issue and the Taiwan crisis forms the main research framework in my thesis. Moreover, combining the attribution theory from psychology and the security dilemma theory from the traditional Realist paradigm gives us new perspectives in viewing the interactions between the United States and China.
The missile defense issue showed that the linkage with the Taiwan issue remains important in changes in perception of the Chinese decision-makers. During the Clinton presidency, the joint effort of China and Russia resulted in the changes in perception of US decision-makers on the missile defense issue and to a large extent, caused the delay in the development of the national missile defense. Then during President Bush presidency, the possible selling of Aegis-equipped naval ships to Taiwan softened the stance of Chinese decision-makers on the MD issue, but the granting of a visa to Taiwanese President Chen caused the Chinese leadership to return to a tough stance on the MD issue.
The Taiwan issue is nevertheless an important case in my research and particular focus is given to the background of the 1996 Taiwan straits crisis. The 1992 US arms sales to Taiwan started the process but the 1995 granting of a visa to Taiwanese President Lee was the prime stimulus that reinforced China’s hostile image of US decision-makers, which resulted in the changes in the foreign policies of the Chinese leadership. In turn, the Chinese military tests also shaped the perception of US decision-makers and hence US policies towards the Taiwan straits situation also changed. Decision-makers’ changes in perception and foreign policies led to the formation of the 1996 Taiwan straits crisis in consequence.
Judging from my findings, the basic theoretical framework is useful in analyzing the dynamics of both issues, but nevertheless there needs to be some modification to my framework. In particular, my analysis shows that the existence of a stimulus with a “credible threat” is necessary to produce a change in core belief and in perception. Moreover, the two theories of the security dilemma and attribution match rather well with the origin and development of the two issues in certain aspects and hence the combination of the three could produce a more comprehensive analysis.
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Su, Sara Lee 1982. "Perceptual picture emphasis using texture power maps." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30181.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.<br>Includes bibliographical references (p. 65-70).<br>Applying selective emphasis to photographs is a critical aspect of the visual design process. There is evidence from psychophysics that contrast in texture is a key contributor to saliency in an image, yet unlike other low-level perceptual features, texture cannot be directly modified with existing image-processing software. We present a post-processing technique to subtly change the salience of regions of an image by modifying spatial variation in texture. Our method is inspired by computational models of visual attention that capture sensitivity to outliers in local feature distributions. We use the steerable pyramid, which encodes multi-scale oriented image features and compute a set of power maps which capture the local texture content at each scale and orientation. With this representation, texture variation can be modified to selectively add or remove emphasis in the image. Two user studies provide qualitative and quantitative psychophysical validation of our approach.<br>by Sara Lee Su.<br>S.M.
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Shao, Yunming. "Image-based Perceptual Learning Algorithm for Autonomous Driving." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503302777088283.
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Hewage, Chaminda T. E. R. "Perceptual quality driven 3-D video over networks." Thesis, University of Surrey, 2008. http://eprints.kingston.ac.uk/22178/.
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3-D video in day to day life will enhance the way we represent real-world sceneries and provide more natural conditions for human interaction. Therefore, 3-D video has the potential to be the next killer application in multimedia communications. However, the demand for resources (e.g. bandwidth), 3-D quality evaluations and providing error protection are challenges to be addressed. Thus, this thesis addresses the issues related to transmission of 3-D video over communication networks including compression, quality evaluations, error resilience and error concealment. The first part of the thesis investigates encoding approaches for 3-D video in terms of compression efficiency and adaptability to existing communication technologies. Moreover, an encoding configuration is proposed for colour plus depth video coding based on scalable video coding principals. The proposed encoding configuration shows improved compression efficiency and scalability which can be utilized to scale conventional video applications into stereoscopic video with a minimum increase to the bandwidth required. Quality evaluation issues of stereoscopic video are addressed in the second part of the thesis. The correlations between objective and subjective quality ratings are derived for the range of compression ratios and packet loss rates considered. The results show high correlation between candidate objective measures (e.g. PSNR of colour image) and the measured 3-D perceptual quality attributes. The third part of the thesis investigates efficient error resilience and concealment methods for backward compatible stereoscopic video transmission over wired/wireless networks. In order to provide enhanced error recovery, the proposed methods utilize inherent characteristics of colour plus depth video and their contributions towards improved perceived quality. The error resilience methods proposed improve 3-D perception compared to equally protected transmission of colour plus depth map video. Similarly, the proposed error concealment methods recover missing information more effectively compared to the deployment of existing 2-D error concealment methods.
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Yeddanapudi, Neelima 1976. "Characterizing the perceptual diffusion of auditory lateralization images." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/29722.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.<br>Includes bibliographical references (leaf 44).<br>When two statistically independent noise sources with different interaural time delays are presented simultaneously over headphones, the separated source images seem to become diffuse and merge over time. Experiments were designed to test the hypothesis that the measure of diffusion perceived would increase over time. Target stimuli were created consisting of the two simultaneous sources with different interaural time delays, and attempts were made to study the diffusion as a function of stimulus duration, as well as relative onset of the two noise sources. These target stimuli were compared to a set of partially decorrelated noise stimuli composed of three statistically independent sources. It was hoped that by varying the degree of decorrelation in these comparison stimuli, one could simulate different stages in the transition from two source images to one merged image observed in the target stimuli. The experiments failed to produce the expected results, but strategies for improved experimental designs were devised.<br>by Neelima Yeddanapudi.<br>M.Eng.
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Alwan, Abeer Abdul-Hussain. "Acoustic and perceptual correlates of pharyngeal and uvular consonants." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/34302.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING<br>Bibliography: leaves 138-147.<br>by Abeer Abdul-Hussain Alwan.<br>M.S.
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Stauffer, Christopher P. (Christopher Paul) 1971. "Perceptual data mining : bootstrapping visual intelligence from tracking behavior." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8111.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.<br>Includes bibliographical references (p. 161-166).<br>One common characteristic of all intelligent life is continuous perceptual input. A decade ago, simply recording and storing a a few minutes of full frame-rate NTSC video required special hardware. Today, an inexpensive personal computer can process video in real-time tracking and recording information about multiple objects for extended periods of time, which fundamentally enables this research. This thesis is about Perceptual Data Mining (PDM), the primary goal of which is to create a real-time, autonomous perception system that can be introduced into a wide variety of environments and, through experience, learn to model the activity in that environment. The PDM framework infers as much as possible about the presence, type, identity, location, appearance, and activity of each active object in an environment from multiple video sources, without explicit supervision. PDM is a bottom-up, data-driven approach that is built on a novel, robust attention mechanism that reliably detects moving objects in a wide variety of environments. A correspondence system tracks objects through time and across multiple sensors producing sets of observations of objects that correspond to the same object in extended environments. Using a co-occurrence modeling technique that exploits the variation exhibited by objects as they move through the environment, the types of objects, the activities that objects perform, and the appearance of specific classes of objects are modeled. Different applications of this technique are demonstrated along with a discussion of the corresponding issues.<br>(cont.) Given the resulting rich description of the active objects in the environment, it is possible to model temporal patterns. An effective method for modeling periodic cycles of activity is demonstrated in multiple environments. This framework can learn to concisely describe regularities of the activity in an environment as well as determine atypical observations. Though this is accomplished without any supervision, the introduction of a minimal amount of user interaction could be used to produce complex, task-specific perception systems.<br>by Christopher P. Stauffer.<br>Ph.D.
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Chang, Jiae. "A PERCEPTUAL VISUALIZATION ASSISTANT FOR MULTI-DIMENSIONAL DATA VISUALIZATION." NCSU, 2001. http://www.lib.ncsu.edu/etd/public/etd-32441612810132541/etd.pdf.
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Prungsinchai, Supakorn. "Robust and secure perceptual image hashing in the transform domain." Thesis, Northumbria University, 2014. http://nrl.northumbria.ac.uk/21427/.
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The rapid development of multimedia devices such as computers, network technologies, and cell phones have made it easier for users to create, broadcast, convey, share, store, and distribute multimedia data including images, videos and audio files on a daily basis. However, the availability of image processing software in the public domain has facilitated illegal copying and distribution of digital images with unnoticeable quality changes. Thus, security and identification of media content has become an important and demanding area for research. Perceptual hashing is one of the recent technologies used for multimedia content security. A perceptual image hash function is a hash function that is robust against content-preserving operations (CPOs), such as noise, JPEG lossy compression and rotation. This aim of this research is to study and investigate existing techniques and then contribute to the development of new perceptual image hashing techniques in the transform domain for image identification and copy detection applications. The design requirements for any perceptual image hashing system are robustness, discriminative capability (uniqueness), and unpredictability (security). The feature extraction stage plays a key role in ensuring the system output is robust and discriminative. This thesis mainly focuses on the robust feature extraction stage and the analysis of the proposed system's security. The following contributions have been made: A new perceptual hashing technique using pseudo-random sub-images in the discrete wavelet transform (DWT) domain for extracting features has been developed. The idea employs a recent dimension reduction technique, referred to as non-negative matrix factorization (NMF) in the literature, for enhancing the robustness and security of the hash. This approach is proposed to select the most stable coefficients under various content-preserving operations, compact. The robust image hashes are generated by applies DWT and NMF into image. The proposed sub-images-DWT technique has been shown to yield good performance under image processing operations, but it still suffers from geometric attacks. A new rotation-invariant FMT-based hashing technique incorporating the Fourier-Mellin transform and using overlapping blocks to improve the robustness against rotation attacks has also been proposed. The robust FMT-based image hashing is proposed to improve its performances under rotation, translation attacks and achieve better overall robustness. The invariance property to rotation, scaling and translation of FMT makes it more suitable for image hashing. Based on our experimental results, it has been shown that the proposed FMT-based image hashing technique is robust to a large class of image processing operations and geometric attacks. A new robust and secure DCT overlapping block-based hashing technique incorporating the discrete cosine transforms (DCT) to combat image processing attacks has been investigated. An improved DCT sign-based hashing technique robust against image processing attacks and well as small geometric manipulations developed. From the experimental results, it was observed that the low frequency coefficients for DCT sign based-image hashing were robust to a large of content-preserving operations (CPOs). The main idea was to exploit the energy compaction property of the DCT and its ability to carry information of edges and texture in DCT sign values. From the experimental results, it was observed that the low frequency coefficients for DCT sign-based image hashing were robust to a large class of content-preserving operations (CPOs). The main idea was to exploit the energy compaction property of the DCT and its ability to carry information of edges and texture in DCT sign values. Finally, the security of the proposed image hashing systems are discussed and analysed in the light of the corresponding design requirement. The DCT sign-based image hashing scheme has hash also been shown to be the most secure technique compared to other techniques proposed in this research as it offers the highest rate of bit independence in a hash.
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Watts, Stephanie Anne. "Perceptual and Physiologic Analysis of Dystussia in Amyotrophic Lateral Sclerosis." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7105.
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Swallowing and cough are two vital functions that are reflexive in nature and are related to each other in terms of shared neural and anatomical space. When a disorder impacts normal and effective swallowing and/or cough, the consequences can be life-threatening. Evaluation and treatment of swallowing and cough disorders can fall under the scope of practice of the speech-language pathologist and speech-language pathologists often are leading professionals. Furthermore, much of the current research on swallowing and cough is spearheaded by speech-language pathologists often working with a multi-disciplinary team. The focus of this dissertation is on the clinical evaluation of cough and swallowing, practice patterns of voluntary cough assessment during the evaluation of swallowing, and novel methods of evaluating acoustic voluntary cough waveforms in patients with and without swallowing impairment. The results will provide important information regarding the state of cough assessment tools for clinical swallowing evaluation, clinical practice patterns of voluntary cough assessment, and differences in acoustic cough signals between safe and unsafe swallowers in individuals with Amyotrophic Lateral Sclerosis (ALS).
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Tran, Trac Duy. "A locally adaptive perceptual masking threshold model for image coding." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/34077.
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Coen, Michael Harlan. "Multimodal dynamics : self-supervised learning in perceptual and motor systems." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34022.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Includes bibliographical references (leaves 178-192).<br>This thesis presents a self-supervised framework for perceptual and motor learning based upon correlations in different sensory modalities. The brain and cognitive sciences have gathered an enormous body of neurological and phenomenological evidence in the past half century demonstrating the extraordinary degree of interaction between sensory modalities during the course of ordinary perception. We develop a framework for creating artificial perceptual systems that draws on these findings, where the primary architectural motif is the cross-modal transmission of perceptual information to enhance each sensory channel individually. We present self-supervised algorithms for learning perceptual grounding, intersensory influence, and sensorymotor coordination, which derive training signals from internal cross-modal correlations rather than from external supervision. Our goal is to create systems that develop by interacting with the world around them, inspired by development in animals. We demonstrate this framework with: (1) a system that learns the number and structure of vowels in American English by simultaneously watching and listening to someone speak. The system then cross-modally clusters the correlated auditory and visual data.<br>(cont.) It has no advance linguistic knowledge and receives no information outside of its sensory channels. This work is the first unsupervised acquisition of phonetic structure of which we are aware, outside of that done by human infants. (2) a system that learns to sing like a zebra finch, following the developmental stages of a juvenile zebra finch. It first learns the song of an adult male and then listens to its own initially nascent attempts at mimicry through an articulatory synthesizer. In acquiring the birdsong to which it was initially exposed, this system demonstrates self-supervised sensorimotor learning. It also demonstrates afferent and efferent equivalence - the system learns motor maps with the same computational framework used for learning sensory maps.<br>by Michael Harlan Coen.<br>Ph.D.
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Ahrens, Merle-Marie. "Automatic visuospatial attention shifts : perceptual correlates, interventions and oscillatory signatures." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/30695/.
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Our visual perception is shaped by both external and internal factors, which continuously compete for limited neural resources. Salient external (exogenous) events capture our attention automatically, whereas internal (endogenous) attention can be directed towards sensory events according to our current behavioural goals. Advances in neuroimaging and brain stimulation have allowed us to begin to map the underlying functional neural architecture mediating both exogenously driven and endogenously controlled visual attention, including electrophysiological techniques such as electroencephalography and magnetoencephalography (EEG/MEG). However, while the neural EEG/MEG correlates of endogenously controlled attention have been investigated in much detail, the neural EEG/MEG correlates of exogenously driven attention are substantially less well understood. One reason for this is that exogenously driven effects are difficult to isolate from the influence of endogenous control processes. In a series of three experiments, I sought to: 1) Study how the perceptual outcomes of both endogenously and exogenously driven attention can be effectively dissociated and investigated. 2) Provide a better understanding of the functional architecture of attention control in regards to its underlying neural substrates and oscillatory signatures, particularly when exogenously driven. To this end, I employed a visuospatial attention paradigm which, by design, behaviourally dissociates exogenous from endogenously driven effects (experiment 1). Furthermore, by utilizing the same behavioural paradigm in combination with neuronavigated MRI-based transcranial magnetic stimulation (TMS) over two key attentional network nodes (i.e., the right intraprarietal sulcus and right temporo-parietal junction), I probed the extent to which the neural substrates of endogenous vs. exogenous orienting are overlapping or can be dissociated (experiment 2). Lastly, I used electroencephalography (EEG) to investigate the oscillatory signatures underlying attention in a task which is typically employed to study exogenous orienting and which putatively triggers exogenous attention in isolation (experiment 3). The results revealed that while exogenous attentional processes can be behaviourally dissociated from endogenous attention (experiment 1), the neural substrates of exogenous attention appear to cover a wide network of attention areas. This includes nodes in both the right ventral attention network (i.e., right temporo-parietal junction) but also the right dorsal network (i.e., the right intraparietal sulcus), which has predominantly been associated with endogenous attention control (experiment 2). Interestingly, even in tasks that have been utilized to test exogenous attentional effects in isolation, endogenous control processes, as indexed by increased mid-frontal theta-band activity, can heavily influence the behavioural outcome (experiment 3). Based on these results, I conclude that there appears to be strong interplay between endogenous control and exogenously driven attention processes. These findings highlight that in order to better understand the functional architecture of (purely) exogenously driven effects, we need to effectively account for the potential influence of endogenous control. One approach to achieve this is by manipulating both types of attention simultaneously instead of in separation, as illustrated in the present work.
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Bonneel, Nicolas. "Audio and Visual Rendering with Perceptual Foundations." Phd thesis, Université de Nice Sophia-Antipolis, 2009. http://tel.archives-ouvertes.fr/tel-00432117.
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Realistic visual and audio rendering still remains a technical challenge. Indeed, typical computers do not cope with the increasing complexity of today's virtual environments, both for audio and visuals, and the graphic design of such scenes require talented artists. In the first part of this thesis, we focus on audiovisual rendering algorithms for complex virtual environments which we improve using human perception of combined audio and visual cues. In particular, we developed a full perceptual audiovisual rendering engine integrating an efficient impact sounds rendering improved by using our perception of audiovisual simultaneity, a way to cluster sound sources using human's spatial tolerance between a sound and its visual representation, and a combined level of detail mechanism for both audio and visuals varying the impact sounds quality and the visually rendered material quality of the objects. All our crossmodal effects were supported by the prior work in neuroscience and demonstrated using our own experiments in virtual environments. In a second part, we use information present in photographs in order to guide a visual rendering. We thus provide two different tools to assist “casual artists” such as gamers, or engineers. The first extracts the visual hair appearance from a photograph thus allowing the rapid customization of avatars in virtual environments. The second allows for a fast previewing of 3D scenes reproducing the appearance of an input photograph following a user's 3D sketch. We thus propose a first step toward crossmodal audiovisual rendering algorithms and develop practical tools for non expert users to create virtual worlds using photograph's appearance.
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Williamson, Donald S. "DEEP LEARNING METHODS FOR IMPROVING THE PERCEPTUAL QUALITY OF NOISY AND REVERBERANT SPEECH." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461018277.
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Slawinska, Malgorzata. "Affective responses to exercise : understanding changes in perceptual and cognitive processes." Thesis, Northumbria University, 2017. http://nrl.northumbria.ac.uk/36133/.
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The severe health implications associated with physical inactivity highlight the need for research aiming to elucidate mechanisms underlying individuals’ experience of exercise. Affective responses to exercise have been identified as a central factor shaping exercise behaviour (Ekkekakis, 2003; Kwan & Bryan, 2010; Williams, et al., 2008). Research identifies that external and internal factors influence affective evaluations of exercise. One external factor influencing the evaluation of affective responses is the environmental stimuli comprising the exercise setting (Antoniewicz & Brand, 2014; DaSilva, et al., 2011). Therefore, study one examined the influence of environmental cues on affective and cognitive responses to exercise in an ecologically valid setting. Results revealed significant interactions between environmental cues and affect, and motivation; this suggests that intra-individual processes may influence exercise behaviour. The thesis subsequently investigated internal processes that influence affective evaluations of exercise; in particular, processes underlying the recall of affective experience (Kahneman, et al., 1993). Study two examined individuals’ recall of exercise related affect over a period of two weeks using a randomised control crossover design. Results indicated that exercise related affect fluctuated over the two-week period with a significant drop at 24 hours post low-to-moderate and high intensity exercise trials. Additionally, recalled affect better predicted anticipatory feelings than affect recorded during exercise. The study also found partial support for the peak and end rule particularly for the high intensity exercise. Extending study two’s findings, study three explored the recall of exercise related affect and anticipatory feelings using an experimental design with a self-paced exercise protocol. The study revealed significant changes across postexercise recall with follow-up measures at 8 and 24 hours indicating a substantial decline in affect. Overall findings revealed that contextual factors promote positive affect when aligned with one’s goals; however discordant contextual cues and goals can thwart positive affective responses. Further, recall of affective experiences of exercise dynamically change over time and recalled affect can predict anticipatory feelings of exercise. Lastly, all studies’ findings emphasise on the imperative role of idiographic analysis in research on affective responses to exercise.
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Koppikar, Samir Dilip. "Privacy Preserving EEG-based Authentication Using Perceptual Hashing." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955127/.
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The use of electroencephalogram (EEG), an electrophysiological monitoring method for recording the brain activity, for authentication has attracted the interest of researchers for over a decade. In addition to exhibiting qualities of biometric-based authentication, they are revocable, impossible to mimic, and resistant to coercion attacks. However, EEG signals carry a wealth of information about an individual and can reveal private information about the user. This brings significant privacy issues to EEG-based authentication systems as they have access to raw EEG signals.
This thesis proposes a privacy-preserving EEG-based authentication system that preserves the privacy of the user by not revealing the raw EEG signals while allowing the system to authenticate the user accurately. In that, perceptual hashing is utilized and instead of raw EEG signals, their perceptually hashed values are used in the authentication process. In addition to describing the authentication process, algorithms to compute the perceptual hash are developed based on two feature extraction techniques. Experimental results show that an authentication system using perceptual hashing can achieve performance comparable to a system that has access to raw EEG signals if enough EEG channels are used in the process. This thesis also presents a security analysis to show that perceptual hashing can prevent information leakage.
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Choi, Kang. "The prospect of arms control in northeast Asia : a contextual procedural, and perceptual approach /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487758178238336.
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Barrett, Kathleen. "Corrupted Courts: A Cross-National Perceptual Analysis of Judicial Corruption." unrestricted, 2005. http://etd.gsu.edu/theses/available/etd-04202005-151027/.
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Scassellati, Brian M. "High-level perceptual contours from a variety of low-level physical features." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/38065.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.<br>Includes bibliographical references (p. 87-90).<br>by Brian M. Scassellati.<br>M.Eng.
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Lamel, Lori Faith. "Formalizing knowledge used in spectrogram reading : acoustic and perceptual evidence from stops." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14780.
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Whitehorne, Andrew Ennis. "Telescope: A Multivariate Visualization Framework in Support of the Development of a Perceptual Visualization Hierarchy." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-12202007-122731/.
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Scalability has become a major issue within the field of visualization as data gathering methodologies and display technologies diversify. To compensate for large data sets and display limitations, perceptual visualization techniques aim to optimize graphical data representations with human vision in mind. The following outlines the principles, motivations, and development behind the Telescope multivariate visualization framework. Telescope provides mechanisms for generating and manipulating visualizations in which the visual angle and display resolution of individual elements are of chief concern. This software utilizes ongoing research towards the development of comprehensive perceptual feature guidelines to provide a means of dynamically mapping several common visual features to a given data set. Specific element mappings may be disabled or enabled when the size or display resolution of the displayed data elements crosses a defined threshold. Visualization features of interest are: hue, density, direction, flicker, luminance, orientation, regularity, size, and velocity. The system also allows for the simulation of various viewing environments with concern to display size, resolution, viewing distance, and visual angle. Support is provided for the input of a common data format and the easy manipulation of system parameters by means of a rule system. The end result is a system which lays the foundation for the implementation of a comprehensive perceptual visualization hierarchy.
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Overton, Katherine. "Perceptual Differences in Natural Speech and Personalized Synthetic Speech." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6921.
Full textAbstract:
The purpose of this study was to determine what perceptual differences existed between a natural recorded human voice and a synthetic voice that was created to sound like the same voice. This process was meant to mimic the differences between a voice that would be used for Message Banking and a voice that would be created by the ModelTalker system. Forty speech pathology graduate students (mean age = 23 years) rated voices on clarity, naturalness, pleasantness, and overall similarity. Analysis of data showed that the natural human voice was consistently rated as more natural, clear, and pleasant. In addition, participants generally rated the two voices as very different. This demonstrates that, at least in terms of perception, using the method of Message Banking results in a voice that is overall perceived more positively than the voice created using ModelTalker.
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Acevedo, Feliz Daniel. "A framework for the perceptual optimization of multivalued multilayered two-dimensional scientific visualization methods." View abstract/electronic edition; access limited to Brown University users, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3318287.
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Lao, Junpeng. "Tracking the temporal dynamics of cultural perceptual diversity in visual information processing." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5055/.
Full textAbstract:
Human perception and cognition processing are not universal. Culture and experience markedly modulate visual information sampling in humans. Cross-cultural studies comparing between Western Caucasians (WCs) and East Asians (EAs) have shown cultural differences in behaviour and neural activities in regarding to perception and cognition. Particularly, a number of studies suggest a local perceptual bias for Westerners (WCs) and a global bias for Easterners (EAs): WCs perceive most efficiently the salient information in the focal object; as a contrast EAs are biased toward the information in the background. Such visual processing bias has been observed in a wide range of tasks and stimuli. However, the underlying neural mechanisms of such perceptual tunings, especially the temporal dynamic of different information coding, have yet to be clarified. Here, in the first two experiments I focus on the perceptual function of the diverse eye movement strategies between WCs and EAs. Human observers engage in different eye movement strategies to gather facial information: WCs preferentially fixate on the eyes and mouth, whereas EAs allocate their gaze relatively more on the center of the face. By employing a fixational eye movement paradigm in Study 1 and electroencephalographic (EEG) recording in study 2, the results confirm the cultural differences in spatial-frequency information tuning and suggest the different perceptual functions of preferred eye movement pattern as a function of culture. The third study makes use of EEG adaptation and hierarchical visual stimulus to access the cultural tuning in global/local processing. Culture diversity driven by selective attention is revealed in the early sensory stage. The results here together showed the temporal dynamic of cultural perceptual diversity. Cultural distinctions in the early time course are driven by selective attention to global information in EAs, whereas late effects are modulated by detail processing of local information in WC observers.
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Wang, Mike M. Eng Massachusetts Institute of Technology. "Product perceptual mapping on fashion designs with Gaussian mixture variational autoencoder and triplet loss." Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/121642.
Full textAbstract:
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 51-53).<br>Product perceptual maps are visualizations of the perceptions of products by customers. They provide many advantages to businesses, such as identifying gaps in the market, understanding competition, and finding how new products fit into a market. Conventional product perceptual mapping methods exhibit limitations, particularly in capturing the highly nonlinear structure in product perceptual categories. Therefore, given only a set of images and triplet data representing product co-occurence by consumers, we propose and use a Gaussian mixture variational autoencoder (GMVAE) with triplet loss to create product embeddings. These product embeddings are then flattened into a 2D perceptual map able to be interpreted by human judgment. We test the GMVAE approach on three datasets: (1) a dataset of simple generated data; (2) the MNIST dataset, a dataset of handwritten digits; and (3) the Amazon Fashion dataset, a dataset of product images, product categories, and similar products. The GMVAE method is quantitatively evaluated on its ability to capture product "latent" categories, and qualitatively evaluated on the quality of its 2D perceptual maps compared with those produced by using a conventional perceptual mapping method. We find that across the experiments, the GMVAE method could reasonable capture "latent" perceptual product categories and is more effective than the conventional perceptual mapping baseline in correctly identifying and predicting latent product categories.<br>by Mike Wang.<br>M. Eng.<br>M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
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Hand, Christopher James. "An investigation into the perceptual and cognitive factors affecting word recognition during normal reading." Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/2127/.
Full textAbstract:
The present thesis examines the effects of a range of factors on the processing of written language. The present thesis principally uses eye movement recording technology while participants read short passages of text. Factors known to influence written language processing range from lower-level perceptual constraints to higher-level discourse contingencies. Examples of lower-level to higher-level variables are, respectively, intraword orthographic constraints, such as word-initial letter constraint (WILC) – how many other words share the same three initial letters of a given word; lexical level word frequency – how often a word occurs in written language; and extraword contextual predictability – how likely a word is to occur given the discourse up to the position of the word in the passage. The present thesis not only investigates the main effects of these factors, but also studies the simultaneous effects that these factors have on written language processing. Information acquired from the right of current fixation location – parafoveal preview – is essential for reading to proceed at a normal rate. Preview is typically studied using gaze-contingent display change paradigms – non-foveal text is obscured or manipulated, and effects on eye movement behaviour recorded. The present thesis studies an additional method of measuring the effects of preview, without manipulating the text displayed: launch distance – how far readers’ prior fixation is from a given word, before foveal processing of that word. Visual acuity diminishes as retinal eccentricity increases. The present thesis examines the how the effects of the above factors, and any interactions between them, are modulated by launch distance. Standard effects of frequency and predictability were found across all studies. Lower-frequency words (LF) were processed with greater difficulty than higher-frequency words (HF); low-predictability words (LP) were processed with greater difficulty than (HP) words. Consistent with prior research (Rayner, Ashby, Pollatsek, Reichle, 2004), Experiment 1 found additive effects of frequency and predictability on eye movement behaviour. However, further investigation revealed that when preview was highest (i.e., Near launch distances), frequency and predictability exerted an interactive effect. Experiment 2a further investigated the simultaneous effects of frequency and predictability, addressing methodological concerns about Experiment 1. Principally, that HP contexts in Experiment 1 were medium-predictability (MP), potentially obscuring any interaction, as the acquisition of parafoveal information is influenced by the frequency and predictability of the parafoveal word. Comparing very low-predictability (VLP) items to very high-predictability (VHP) items, the interactive pattern of effects observed in the Near launch distance condition of Experiment 1 was replicated in the global analyses of Experiment 2a. In Experiment 2b, comparisons of HF and LF words in VLP and specifically-designed MP items yielded an additive pattern of effects, consistent with Experiment 1. Furthermore, conditionalised analyses of these items by launch distance showed an interactive pattern of effects, but only at Near launch distances. Conditionalised analyses of HF and LF words in VLP and VHP materials from Experiment 2a revealed an interactive pattern of frequency and predictability effects at both Near and Middle launch distances. It is argued that frequency and predictability can interact under two distinct conditions, but both manners are dependent on preview. When HF and LF words are presented in MP contexts, a high level of preview must be provided by a Near launch distance for an interaction to be observed; when HF and LF words are presented in VHP contexts, sufficient information can be extracted at further launch distances, generating an interactive pattern of effects in global analyses. Experiment 3 examines whether fixation durations are inflated prior to skipping a word in text. An overall non-significant effect of word skipping on prior fixation durations was observed. However, this result was somewhat misleading – inflated fixation durations prior to skipping were observed, but only when to-be-skipped words were either HF or HP; indeed, the largest mean inflation prior to skipping was observed when the to-be-skipped word was both HF and HP. These results suggest that when readers are able to extract most information about parafoveal words (e.g., when those words are HF or HP), fixation durations prior to skipping these words are inflated. It is tentatively suggested that these effects reflect a longer accumulation of information from parafoveal to-be-skipped word. These effects are consistent with models of eye movement control permitting parallel processing of written information, as opposed to a strictly serial approach. Experiments 4a and 4b tested the effects of WILC. Experiment 4a employed a lexical decision task, examining the separate and combined effects of WILC and frequency. LF words were responded to less quickly than HF words. Words with low WILC (LC words; e.g., “clown” shares its initial trigram “clo” with many words) were processed more quickly than words with high WILC (HC words; e.g., “dwarf” shares its initial trigram “dwa” with few words). It is suggested that LC words in a lexical decision task are responded to quickly as their initial trigram is shared by a large number of viable words, facilitating a “word” response. The initial trigrams of HC words are not shared by many other words, potentially hindering a “word” response. Experiment 4b re-tests the role of WILC on eye movement behaviour during reading, based on an earlier study by Lima and Inhoff (1985). Unlike Lima and Inhoff’s study, the frequency and predictability (known to influence the extraction of parafoveal information) of LC and HC target words was also manipulated. In contrast to the findings of Lima and Inhoff (but, consistent with their original prediction), HC words were found to exhibit a processing advantage over LC words in measures of eye movement behaviour reflecting early, lexical processing. Further analyses based on launch distances from, and landing positions within target words suggested that the pattern of effects observed may be due to the accumulation of WILC information from the parafovea. The present thesis finds that word frequency and contextual predictability can yield interactive effects on processing, but that any possible interaction is dependent on acquisition of parafoveal information. Evidence of inflated fixation durations prior to word skipping were observed, but these effects are modulated by the characteristics of the parafoveal to-be-skipped word. Initial letters of words have a substantial effect on processing, but this effect is task-dependent. In lexical decision, activation of “wordness” is advantageous, and LC words exhibit an advantage over HC words. In natural reading, information is available from sentential context and the parafovea, and HC words carry an advantage over LC words. The present thesis argues for the use of launch distance as a metric for measuring preview benefit, albeit in a necessarily post-hoc fashion. Reliable effects of launch distance were found across all experiments where it was examined as a factor – eventual fixation time on a word increases as the distance of prior fixation from beginning of that word increases. Launch distance was also shown to influence the effects of a range of factors which influence written language processing, and the interactions between these variables.
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Prangnell, Lee. "Visually lossless coding for the HEVC standard : efficient perceptual quantisation contributions for HEVC." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/106761/.
Full textAbstract:
In the context of video compression, visually lossless coding refers to a form of perceptual compression. The objectives are as follows: i) to lossy code a raw video sequence to the lowest possible bitrate; ii) to ensure that the compressed sequence is perceptually identical to the raw video data. Because of the vast bitrate reductions which cannot otherwise be achieved, the research and development of visually lossless coding techniques (e.g., perceptual quantisation methods) is considered to be important in contemporary video compression research, particularly for the High Efficiency Video Coding (HEVC) standard. The default quantisation techniques in HEVC — namely, Uniform Reconstruction Quantisation (URQ) and Rate Distortion Optimised Quantisation (RDOQ) — are not perceptually optimised. Neither URQ nor RDOQ take into account the Modulation Transfer Function (MTF)-based visual masking properties of the Human Visual System (HVS); e.g., luma and chroma spatial masking. Moreover, URQ and RDOQ do not intrinsically possess the capacity to distinguish luma data from chroma data. Both of these shortcomings can lead to coding inefficiency (i.e., wasting bits by not removing perceptually irrelevant data). Therefore, it is desirable to develop visually lossless coding (perceptual quantisation) techniques for HEVC. For example, by taking chrominance masking into account, perceptual quantisation techniques can be designed to discard — to a very high degree — chroma-based psychovisual redundancies from the chroma channels in raw YCbCr video data. To this end, four novel perceptual quantisation contributions are proposed in this thesis. In Chapter 3, a novel transform coefficient-level perceptual quantisation method is proposed. In HEVC, each frequency sub-band in the Discrete Cosine Transform (DCT) frequency domain constitutes a different level of perceptual importance to the HVS. In terms of perceptual importance, the DC coefficient (very low frequency) is the most important transform coefficient, whereas the AC coefficients farthest away from the DC coefficient (very high frequency AC coefficients) are the least perceptually relevant. Therefore, the proposed technique is designed to quantise AC coefficients based on their Euclidean distance from the DC coefficient. In Chapter 4, two novel perceptual quantisation methods are proposed, which are based on HVS visual masking in the spatial domain. The first technique operates at the Coding Unit (CU) level and the second operates at the Coding Block (CB) level. Both techniques exploit the fact that the HVS can tolerate high levels of distortion in high variance (busy) regions of compressed luma and chroma data. The CU-level method adjusts the Quantisation Parameter (QP) of a 2N×2N CU based on cross colour channel variance computations. The CB-level technique separately adjusts the QP of the Y, Cb and Cr CBs in a CU based on separate variance computations in each colour channel. In Chapter 5, a novel CB-level luma and chroma perceptual quantisation technique — based on a Just Noticeable Distortion (JND) model — is proposed for HEVC. The objective of this technique is to attain visually lossless coding at extremely low bitrates by exploiting HVS-related luminance adaptation and chrominance adaptation. Consequently, this facilitates JND perceptual quantisation based on luminance spatial masking and chrominance spatial masking. The proposed technique applies high levels of perceptual quantisation to luma and chroma data, which is achieved by separately adjusting the Quantisation Step Sizes (QSteps) at the level of the Y CB, the Cb CB and the Cr CB in a CU. To the best of the author’s knowledge, this is the first JND-based perceptual quantisation technique that is compatible with high bit depth YCbCr data irrespective of its chroma sampling ratio. The novel techniques proposed in this thesis are evaluated thoroughly. The methodology utilised in the experiments consists of an exhaustive subjective visual quality assessment in addition to an extensive objective visual quality evaluation. The subjective evaluation is based on the International Telecommunications Union (ITU) standardised assessments known as ITU-R: Rec. P.910. In these tests, several participants undertake a considerable number of subjective visual inspections (e.g., spatiotemporal analyses of the compressed sequences versus the raw video data) to ascertain the efficacy of the proposed contributions. The objective visual quality evaluation includes quantifying the mathematical reconstruction quality of the video data compressed by the proposed techniques. This is carried out by employing the Structural Similarity Index (SSIM) and Peak Signal-to-Noise Ratio (PSNR) visual quality metrics.
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Fitzpatrick, Paul Michael 1974. "From first contact to close encounters : a developmentally deep perceptual system for a humanoid robot." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/16951.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.<br>Includes bibliographical references (p. 139-152).<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>This thesis presents a perceptual system for a humanoid robot that integrates abilities such as object localization and recognition with the deeper developmental machinery required to forge those competences out of raw physical experiences. It shows that a robotic platform can build up and maintain a system for object localization, segmentation, and recognition, starting from very little. What the robot starts with is a direct solution to achieving figure/ground separation: it simply 'pokes around' in a region of visual ambiguity and watches what happens. If the arm passes through an area, that area is recognized as free space. If the arm collides with an object, causing it to move, the robot can use that motion to segment the object from the background. Once the robot can acquire reliable segmented views of objects, it learns from them, and from then on recognizes and segments those objects without further contact. Both low-level and high-level visual features can also be learned in this way, and examples are presented for both: orientation detection and affordance recognition, respectively. The motivation for this work is simple. Training on large corpora of annotated real-world data has proven crucial for creating robust solutions to perceptual problems such as speech recognition and face detection. But the powerful tools used during training of such systems are typically stripped away at deployment. Ideally they should remain, particularly for unstable tasks such as object detection, where the set of objects needed in a task tomorrow might be different from the set of objects needed today. The key limiting factor is access to training data, but as this thesis shows, that need not be a problem on a robotic platform that can actively probe its environment, and carry out experiments to resolve ambiguity.<br>(cont.) This work is an instance of a general approach to learning a new perceptual judgment: find special situations in which the perceptual judgment is easy and study these situations to find correlated features that can be observed more generally.<br>by Paul Michael Fitzpatrick.<br>Ph.D.
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Rathbone, Ingha. "Perceptual-motor development for children who show signs of attention deficit hyperactivity disorder (ADHD)." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2071.
Full textAbstract:
Thesis (M Sport Sc (Sport Science))--University of Stellenbosch, 2009.<br>ENGLISH ABSTRACT: The influence of a six-week perceptual-motor and attentional skills programme,
combined with teaching strategies, on the motor proficiency and attentional
abilities of children diagnosed with ADHD was investigated. The five case study
individuals (ranging for Grade 1- 7) took part in a six-week Purposeful Play
Programme. Baseline, pre-test and post-test scores were obtained from the
Bruininks- Oseretsky Test of Motor Proficiency (BOTMP) and Attention-Deficit
Hyperactivity Disorder Test (ADHDT). All five case study individuals showed a
significant improvement on their motor proficiency during retention tests as well as
improvements on some of the behavioural soft signs of hyperactivity, impulsivity
and inattention.<br>AFRIKAANDE OPSOMMING: Die invloed van ʼn sesweek perseptueel-motoriese en
aandagvaardigheidsprogram, gekombineer met onderrigstrategieë, is op die
motoriese vaardighede en aandagvermoëns van kinders gediagnoseer met ATHS,
bestudeer. Die vyf gevallestudie individue (tussen Graad 1- 7) het aan „n sesweek
Purposeful Play Programme deelgeneem. Die basislyn-, voor- en natoetstellings is
verkry vanaf die Bruininks- Oseretsky Test of Motor Proficiency (BOTMP) en
Attention-Deficit Hyperactivity Disorder Test (ADHDT). Al vyf gevallestudie
individue het ʼn beduidende verbetering in motoriese vaardigheid getoon tydens
retensietoetse asook verbetering in sommige van die gedragstekens van
hiperaktiwiteit, impulsiwiteit en afleibaarheid.
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Ramabhai, Leena I. "The effect of load carriage on selected metabolic and perceptual responses of military personnel." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005189.
Full textAbstract:
Taking a multi-disciplinary, integrated approach, the present study sought to examine selected physiological and psycho-physical parameters related to load carriage involving a 12 km march under military conditions. Military constraints hampered, but did not entirely inhibit the secondary aim of the study which concerned the effectiveness of relativising loads in order to normalise responses for all soldiers, irrespective of morphological diversity. Forty three subjects were measured in six groups using a test-retest experimental protocol. They were involved in a rest-broken 12 km march at 4 km.h⁻¹ under 40.5 kg absolute total load and under a relative load of 37% of body mass. Heart rates, ratings of perceived exertion (RPE) as well as area and intensity of discomfort were monitored for all subjects. Ten subjects were measured more extensively with regard to physiology using the Metamax, a portable ergospirometry system that provides all the data needed for a complete functional analysis of lung, heart, circulation and metabolic activity. Physiological responses (fc; fb; V̇T; V̇E; V̇O₂; EE; V̇CO₂; R; T°) indicated subjects were not severely physically taxed and that the loads imposed constituted a sub-maximal demand. Moreover, there appeared to be a limited cumulative effect over the 3.5 h. Data from the first and third hours were similar, while the significantly higher responses in the second hour reflected the challenge of the undulating terrain encountered during this section of the march. All responses during the Relative load conditions mirrored those of the Absolute load condition but, because the demands were less, the trends occurred at a reduced level. Furthermore, the reduction in inter-individual variability indicates that relativised load carriage tends to stress the soldiers in a more uniform manner. All "local" RPE responses were higher than "central" ratings, suggesting soldiers were in good cardiovascular condition and experienced marginally more strain in the lower limbs. There was increased perceived strain corresponding to the increase in gradient, with little cumulative effect over the three hours. The shoulders and feet were the two regions in which most discomfort was experienced; the shoulders being the worst area in the first hour and the feet being rated the worst after the third hour of marching. This study clearly demonstrates the probability of a significant improvement in mean combat-readiness following loaded marching by showing that, if loads are set at levels commensurate with individual capabilities to carry them without undue strain, unnecessary physical demands experienced by smaller, more gracile soldiers are reduced.
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Walters, Yolinda. "The effects of a perceptual-motor development program on children with Developmental Coordination Disorder." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1302.
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Hu, Hongzhan. "Exploring the concept of feedback with perspectives from psychology and cognitive science." Thesis, Linköpings universitet, Interaktiva och kognitiva system, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-107090.
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This study explores the concept of feedback from various perspectives in psychology and cognitive science. Specifically, the theories of ecological psychology, situated and Distributed Cognition, Cognitive Systems Engineering and Embodied cognition are investigated and compared. Cognitive Systems Engineering provides a model of feedback and related constructs, to understand human behavior in complex working environments. Earlier theories such as ecological psychology, considered feedback as direct perception. Situated cognition clearly inherits ideas from ecological psychology, whereas distributed cognition provides a deeper understanding of feedback through artifact use. Cognitive Systems Engineering provides a systematic view of feedback and control. This framework is a suitable perspective to understanding feedback in human-machine settings.
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Van, Velden Grant David. "The effect of a perceptual-motor training programme on the coincident anticipation timing and batting performance of club cricket players." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5381.
Full textAbstract:
Thesis (M Sport Sc (Sport Science)-- University of Stellenbosch, 2010.<br>ENGLISH ABSTRACT: The purpose of this study was to determine the effects of a perceptual-motor training programme on the coincident anticipation timing and batting performance of university club cricket players. The intervention programme focused on developing players‟ visual attention and concentration. Vickers‟ (2007) Three-Step Decision Training Model was used to structure the training sessions.
The study followed a repeated measures experimental design with three groups (experimental, placebo, and control) formed by volunteers from a university club cricket team. The independent variable was a four-week training programme. The dependent variables were coincident anticipation timing and performance on a cricket batting test. Subjects were pre- and post-tested with retention tests occurring after a set period of “no training” following the post-tests.
Differences between groups were compared using Kruskal-Wallis ANOVA by Ranks Tests. Differences within each group were compared using multiple Mann-Whitney U-Tests. No significant improvements were observed in the experimental group‟s coincident anticipation timing and batting performance. Although neither coincident anticipation timing nor batting performance significantly improved, further research into the use of Vickers‟ (2007) Model to enhance sport performance is recommended.<br>AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die uitwerking van ʼn perseptueel-motoriese opleidingsprogram op die samevallende vooruittydsberekening (“coincident anticipation timing”) en kolfprestasie van universiteitsklubkrieketspelers te bepaal. Die klem van die intervensieprogram het op die ontwikkeling van spelers se visuele aandag en konsentrasie geval. Die opleidingsessies is volgens Vickers (2007) se drieledige model vir besluitnemingsopleiding saamgestel.
Die studie het ʼn eksperimentele ontwerp van herhaalde metings op drie groepe (eksperimenteel, plasebo en kontrole) van ʼn universiteitsklubkrieketspan toegepas. Die onafhanklike veranderlike was ʼn vier weke lange opleidingsprogram. Die afhanklike veranderlikes was samevallende vooruittydsberekening, en prestasie in ʼn krieketkolftoets. Proefpersone het voor en net ná die opleiding toetse ondergaan, sowel as behoudtoetse drie weke ná die na-opleidingstoetse.
Verskille tussen groepe is met behulp van rangtoetse uit Kruskal-Wallis se variansie-analisemodel (ANOVA) bepaal, terwyl verskille binne groepe met veelvuldige Mann-Whitney-U-toetse vergelyk is. Geen beduidende verbetering is in die eksperimentele groep se samevallende vooruittydsberekening of kolfprestasie waargeneem nie. Hoewel nóg samevallende vooruittydsberekening nóg kolfprestasie aansienlik verbeter het, word verdere navorsing oor die gebruik van Vickers (2007) se model vir die verbetering van sportprestasie aanbeveel.
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De, Haan Ann I. "The effects of a sensory motor development programme on selected variables of school readiness." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50147.
Full textAbstract:
Thesis (MScSportSc)--University of Stellenbosch, 2004.<br>ENGLISH ABSTRACT: The purpose of this investigation was to determine whether a sensory motor
development programme could have an effect on some of the underlying physical
and perceptual abilities that support school readiness. The control group
consisted of 23 children and the two intervention groups of 79 children in total. All
of the children were enrolled in a pre-primary school programme in a local
community. They were all six years old by the end of the intervention. The
Movement Assessment Battery for Children (Henderson & Sugden, 1992) was
used to assess the children on their manual dexterity, eye-hand coordination,
static balance and dynamic balance. The intervention programme consisted of
two phases of 10 weeks each, during which the sensory motor development
activities were presented to the two intervention groups.
Results of the investigation revealed there were significant improvements for some
of the children on selected variables that underlie school readiness. It can be
concluded that participation in a sensory motor development programme can
make a significant contribution to school readiness for many children.<br>AFRIKAANSE OPSOMMING: Die doel van hierdie ondersoek was om te bepaal of 'n sensories-motoriese
ontwikkelingsprogram enige uitwerking op bepaalde onderliggende fisiese en
perseptuele vermoëns wat tot skoolgereedheid by jong kinders bydra, sou kon hê.
Die kontrolegroep het uit drie-en-twintig kinders bestaan. Die twee tussentredende
groepe het altesaam uit nege-en-sewentig kinders bestaan. Die kinders was almal
pre-primêre skoolprogramleerders vanuit 'n plaaslike gemeenskap. Teen die
einde van die intrede het al die betrokke kinders sesjarige ouderdom bereik.
Movement Assessment Battery for Children (Hendersen & Sugden, 1992) is as
riglyn gebruik om die kinders se handvaardigheid, oog-hand-koërdinasie, statiese
en dinamiese balans te evalueer. Die tussentredeprogram het bestaan uit twee
fases van tien weke elk. Die sensoriese-motoriese ontwikkelingsaktiwiteite is
terselfdertyd vir die twee tussentredegroepe aangebied.
Die resultate van die ondersoek het beduidende vordering in sommige kinders
getoon, spesifiek ten opsigte van bepaalde veranderlikes onderliggend aan
skoolgereedheid. Hierdie bevinding dui daarop dat sodanige deelname in 'n
sensories-motoriese ontwikkelingsprogram wel 'n betekenisvolle bydrae tot die
ontwikkeling van skoolgereedheid in baie kinders kan maak.
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Brown, David J. "Complexity, the auditory system, and perceptual learning in naïve users of a visual-to-auditory sensory substitution device." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8985.
Full textAbstract:
Sensory substitution devices are a non-invasive visual prostheses that use sound or touch to aid functioning in the blind. Algorithms informed by natural crossmodal correspondences convert and transmit sensory information attributed to an impaired modality back to the user via an unimpaired modality and utilise multisensory networks to activate visual areas of cortex. While behavioural success has been demonstrated in non-visual tasks suing SSDs how they utilise a metamodal brain, organised for function is still a question in research. While imaging studies have shown activation of visual cortex in trained users it is likely that naïve users rely on auditory characteristics of the output signal for functionality and that it is perceptual learning that facilitates crossmodal plasticity. In this thesis I investigated visual-to-auditory sensory substitution in naïve sighted users to assess whether signal complexity and processing in the auditory system facilitates and limits simple recognition tasks. In four experiments evaluating; signal complexity, object resolution, harmonic interference and information load I demonstrate above chance performance in naïve users in all tasks, an increase in generalized learning, limitations in recognition due to principles of auditory scene analysis and capacity limits that hinder performance. Results are looked at from both theoretical and applied perspectives with solutions designed to further inform theory on a multisensory perceptual brain and provide effective training to aid visual rehabilitation.
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Creasy, Robert. "Performance, physiological, and perceptual effects of wearing graduated compression stockings during running : a thesis presented in partial fulfilment of the requirements for a degree of Master of Science in Sport and Exercise Science at Massey University, Auckland, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/866.
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Purpose: The aims of these studies were to examine the effects of wearing different grades of graduated compression stockings (GCS) on performance, physiological, and perceptual measures before, during, and after exercise in well-trained runners. Method: Two separate running studies were conducted where participants wore different grades of GCS compared with a placebo control stocking in random, counter-balanced order: (1) a field study focussed on a series of 10-km running performances on a 400m track; (2) a laboratory study that examined the effects of 40-min treadmill running on physiological, perceptual, and muscle function responses. Changes in muscle function and damage were determined pre- and post-run by measuring creatine kinase (CK) and myoglobin (Mb) concentrations, counter-movement jump (CMJ) height, muscle soreness, and pressure sensitivity. Physiological measurements of heart rate (HR), oxygen uptake (V&O2), blood lactate concentration [La], and ratings of perceived exertion (RPE) were measured during running. Pre- and post-run perceptual scales assessed comfort, tightness and pain associated with wearing GCS. Results: There were no significant differences in 10-km run time, mean HR, V&O2, [La], and RPE for participants wearing different GCS in (1) and (2) (P<0.05). Con and Low were rated most comfortable (P<0.05) and Hi were tightest (P<0.05) and induced more pain (P<0.05) when GCS were compared in both studies. CMJ was better in participants wearing Low and Med GCS post-run compared with Con in (1) and for Con and all GCS at 0 h post-exercise in (2). CK and Mb levels were higher (P<0.05) and pressure sensitivity was more pronounced (P<0.05) at 0 h post-run for Con and all GCS (2). Few participants (4/10) reported muscle soreness at any one location in (2). Conclusions: Well-trained runners did not experience improved performance, physiological, or perceptual responses when wearing different grades of GCS during 10- km track or 40 min treadmill running compared with a control garment. 40 min treadmill running at 80% V&O2 max may not be strenuous enough to elicit a loss of muscle function in well-trained runners. Runners felt more comfortable wearing GCS that had less compression.
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Lioliou, Aspasia. "On the resilience of perceptual states in foreign policy shaping or the antinomy of reversibility in patterns of foreign policy behaviour : a case study on Greek Socialist foreign policy decision making during the time period 1981-1989." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270317.
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The empirical theme of the present thesis draws upon the foreign policy decision-making processes, which were implemented by the Greek Socialist Government during its first two consecutive terms in office over the time-period extending from October 1981 until June 1989. Whilst the empirical scope of the thesis covers a particular set of foreign policy decisional sequences. which substantiated politically the pursuit of PASOK's ideological endeavours, the analytical orientations of the thesis involve an examination of similar sequences in the light of a set of specific. methodologically induced hypotheses and reflect a set of elemental philosophical preoccupations. By focusing upon a set of specific aspects of the empirical matter approached. the thesis engages upon an analytical discussion of. and adopts a methodological approach to. a characteristic epistemological dichotomy: that formed between interfaces established by perception-based norms of foreign policy behaviour and the philosophical agency exuded by a set of political semantics. Thus. the thesis discusses the empirical and analytical diversity which may characterise the intersubjectively real and the subjectively described. By emphasising the importance attributed to perceptual states in the framework of foreign policy shaping. the thesis raises empirically tangible questions about the extent to which perceptual formats may actually establish objectifiable patterns of foreign policy behaviour and legitimise their inherent ideological rationaJes. In such terms. the theoretical theme of the thesis revolves around the seminal issue of the behavioural agency exercised by perceptual states. which may inexorably determine the substance of actual foreign policy decision-making.
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Markgraaff, Christine. "A programme to improve gross motor and selected visual perception skills of children who show signs of developmental coordination disorder." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4246.
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Thesis (M Sport Sc (Sport Science))--University of Stellenbosch, 2010.<br>ENGLISH ABSTRACT: The purpose of this study was to determine the impact of participation in a small group-based perceptual-motor training programme on the gross motor and visual-motor integration skills of children who show signs of Developmental Coordination Disorder (DCD). Two physical education teachers selected 22 children for assessment as potential participants for this study. The Movement ABC (M-ABC) was then administered to this group and the eight children who scored the lowest were invited to volunteer for this study. These children all volunteered and then completed the assessment of their visual-motor integration skills as measured by the Developmental Test of Visual Perception (DTVP-2).
The study followed an evaluative case study design in which changes in the gross motor and visual-motor integration skills of each participant were reported and interpreted individually. The six-week intervention programme was focused on developing the perceptual-motor link between throwing, catching and balancing skills with challenges to visual skills development, especially eye-hand coordination.
A comparison of pre-test, post-test and retention test scores in the M-ABC revealed that the programme had a positive effect on six of the children. The results for the seventh child were inconsistent on each test occasion, leading to the conclusion that he may have a co-morbid disorder related to attention. Improvements in static balance were noted and some children also experienced improvements in their ball skills (aiming and coincident timing) which brings the researcher to the conclusion that the programme was effective for gross motor development. DTVP-2 results showed improvements in eye-hand coordination in five of the seven children. According to the VMI quotient score, only one child improved, one deteriorated and the rest showed no change which brings the researcher to the conclusion that the intervention programme was not effective for visual-motor integration.<br>AFRIKAANSE OPSOMMING: Die doel van die studie was om die impak te bepaal van deelname in „n klein-groep gebaseerde perseptueel-motoriese oefenprogram op die groot motoriese en visueel-motoriese integrasievaardighede van kinders met tekens van die Ontwikkelingskoördinasie-afwyking (DCD). Twee Lewensoriëntering-onderwysers het 22 kinders geïdentifiseer vir assessering as potensiële deelnemers aan die studie. Hierdie groep het die Beweging-ABC toets (M-ABC) ondergaan en die agt deelnemers met die laagste uitslae is uitgenooi om aan die studie deel te neem. Hierdie agt kinders het ingestem en daarna is die assessering voltooi deur hulle visueel-motoriese integrasievaardighede te meet deur middel van die Ontwikkelingstoets vir Visuele Persepsie (DTVP-2).
Die studie het „n evaluerende gevallestudie-ontwerp gevolg waarin die veranderings tussen die groot motoriese en visueel-motoriese integrasievaardighede van elke deelnemer individueel geïnterpreteer en gerapporteer is. Die ses week-intervensieprogram het gefokus op die ontwikkeling van die perseptueel-motoriese skakel tussen gooi-, vang- en balans-vaardighede met uitdagings vir die ontwikkeling van visuele vaardighede, veral oog-hand koördinasie.
„n Vergelyking tussen die voor-, na- en opvolgtoetse van die M-ABC se toetstellings het getoon dat die program „n positiewe effek op ses van die kinders se groot motoriese vaardighede gehad het. Die uitslag van die sewende kind was teenstrydig tydens elke toetsgeleentheid en dit het gelei tot die gevolgtrekking dat hy moontlik aan „n addisionele afwyking mag ly wat verband hou met „n aandagprobleem. Verbeterings in statiese balans is waargeneem en sommige kinders het ook „n verbetering in balvaardighede getoon (akkuraatheid en reaksietyd). Volgens die DTVP-2 resultate was daar verbeterings in oog-hand koördinasie by vyf van die sewe kinders. Volgens die VMI-kwosiënttelling het slegs een kind verbeter, een het versleg en die ander vyf het geen verandering getoon nie. Die navorser kom dus tot die gevolgtrekking dat die intervensieprogram nie effektief is vir visueel-motoriese integrasie nie.
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Truck, Isis. "Calculs à l'aide de mots : vers un emploi de termes linguistiques de bout en bout dans la chaîne du raisonnement." Habilitation à diriger des recherches, Université Paris VIII Vincennes-Saint Denis, 2011. http://tel.archives-ouvertes.fr/tel-00639737.
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Le contexte général de mes travaux de recherche se situe dans le domaine de la représentation, modélisation puis combinaison des connaissances en milieu imprécis et vague, en particulier dans la théorie des sous-ensembles flous, d'une part, et dans la théorie des multi-ensembles, d'autre part. Dans ce contexte, nous nous attachons à concevoir des modèles ou outils linguistiques pour palier les problèmes d'imprécision. Notre travail s'est d'abord fondé sur la modulation, préservant la simplicité d'un espace de variables linguistiques de cardinalité assez faible mais sur lequel un large éventail de nuances peut être appliqué. Puis nous avons utilisé ces modèles et outils dans des contextes où l'expression de nuances est très importante, comme le *perceptual computing* dans le domaine de la classification des couleurs ou encore le jeu théâtral, et, plus récemment, pour la capture des intentions des programmeurs pour établir des politiques de contrôle et d'adaptation dynamique des architectures logicielles selon l'approche du calcul auto-régulé (*autonomic computing*).
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Ren, Feng Hui. "Multi-image query content-based image retrieval." Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20070103.143624/index.html.
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Feldman, Jacob 1965. "Perceptual decomposition as inference." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/13693.
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Tsingos, Nicolas. "MODELS AND ALGORITHMS FOR INTERACTIVE AUDIO RENDERING." Habilitation à diriger des recherches, Université de Nice Sophia-Antipolis, 2008. http://tel.archives-ouvertes.fr/tel-00629574.
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Les systèmes de réalité virtuelle interactifs combinent des représentations visuelle, sonore et haptique, afin de simuler de manière immersive l'exploration d'un monde tridimensionnel représenté depuis le point de vue d'un observateur contrôlé en temps réel par l'utilisateur. La plupart des travaux effectués dans ce domaine ont historiquement port'e sur les aspects visuels (par exemple des méthodes d'affichage interactif de modèles 3D complexes ou de simulation réaliste et efficace de l'éclairage) et relativement peu de travaux ont été consacrés 'a la simulation de sources sonores virtuelles 'également dénommée auralisation. Il est pourtant certain que la simulation sonore est un facteur clé dans la production d'environnements de synthèse, la perception sonore s'ajoutant à la perception visuelle pour produire une interaction plus naturelle. En particulier, les effets sonores spatialisés, dont la direction de provenance est fidèlement reproduite aux oreilles de l'auditeur, sont particulièrement importants pour localiser les objets, séparer de multiples signaux sonores simultanés et donner des indices sur les caractéristiques spatiales de l'environnement (taille, matériaux, etc.). La plupart des systèmes de réalité virtuelle immersifs, des simulateurs les plus complexes aux jeux vidéo destin'es au grand public mettent aujourd'hui en œuvre des algorithmes de synthèse et spatialisation des sons qui permettent d'améliorer la navigation et d'accroître le réalisme et la sensation de présence de l'utilisateur dans l'environnement de synthèse. Comme la synthèse d'image dont elle est l'équivalent auditif, l'auralisation, appel'ee aussi rendu sonore, est un vaste sujet 'a la croisée de multiples disciplines : informatique, acoustique et 'électroacoustique, traitement du signal, musique, calcul géométrique mais également psycho-acoustique et perception audio-visuelle. Elle regroupe trois problématiques principales: synthèse et contrôle interactif de sons, simulation des effets de propagation du son dans l'environnement et enfin, perception et restitution spatiale aux oreilles de l'auditeur. Historiquement, ces trois problématiques émergent de travaux en acoustique architecturale, acoustique musicale et psycho-acoustique. Toutefois une différence fondamentale entre rendu sonore pour la réalité virtuelle et acoustique réside dans l'interaction multimodale et dans l'efficacité des algorithmes devant être mis en œuvre pour des applications interactives. Ces aspects importants contribuent 'a en faire un domaine 'a part qui prend une importance croissante, tant dans le milieu de l'acoustique que dans celui de la synthèse d'image/réalité virtuelle.
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Casasanto, Daniel J. "Perceptual foundations of abstract thought." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34129.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, 2005.<br>Includes bibliographical references (p. 75-78).<br>How do people think about things they can never see or touch? The ability to invent and reason about domains such as time, ideas, or mathematics is uniquely human, and is arguably the hallmark of human sophistication. Yet, how people mentally represent these abstract domains has remained one of the great mysteries of the mind. This dissertation explores a potential solution: perhaps the mind recruits old structures for new uses. Perhaps sensory and motor representations that result from physical interactions with the world (e.g., representations of physical space) are recycled to support our thinking about abstract phenomena. This hypothesis is motivated, in part, by patterns observed in language: in order to talk about abstract things, speakers often recruit metaphors from more concrete or perceptually rich domains. For example, English speakers often talk about time using spatial language (e.g., a long vacation; a short meeting). Cognitive linguists have argued such expressions reveal that people conceptualize abstract domains like time metaphorically, in terms of space. Although linguistic evidence for this Conceptual Metaphor Theory is abundant, the necessary nonlinguistic evidence has been elusive.<br>(cont.) In two series of experiments, I investigated whether mental representations that result from physical experience underlie people's more abstract mental representations, using the domains of space and :!I.:e as a testbed. New experimental tools were developed in order to evaluate Conceptual Metaphor Theory as an account of the evolution and structure of abstract concepts, and to explore relations between language and nonlinguistic thought. Hypotheses about the way people represent space and time were based on patterns in metaphorical language, but were tested using simple psychophysical tasks with nonlinguistic stimuli and responses. Results of the first set of experiments showed that English speakers incorporate irrelevant spatial information into their estimates of time (but not vice versa), suggesting that people not only talk about time using spatial language, but also think about time using spatial representations. The second set of experiments showed that (a) speakers of different languages rely on different spatial metaphors for duration, (b) the dominant metaphor in participants' first languages strongly predicts their performance on nonlinguistic time estimation tasks, and (c) training participants to use new spatiotemporal metaphors in language changes the way they estimate time.<br>(cont.) Together, these results demonstrate that the metaphorical language people use to describe abstract phenomena provides a window on their underlying mental representations, and also shapes those representations. The structure of abstract domains such as time appears to depend, in part, on both linguistic experience and on physical experience in perception and motor action.<br>by Daniel J. Casasanto.<br>Ph.D.
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Feldman, Jacob 1965. "Perceptual categories and world regularities." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12883.
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Mikheeva, Olga. "Perceptual facial expression representation." Thesis, KTH, Robotik, perception och lärande, RPL, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217307.
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Facial expressions play an important role in such areas as human communication or medical state evaluation. For machine learning tasks in those areas, it would be beneficial to have a representation of facial expressions which corresponds to human similarity perception. In this work, the data-driven approach to representation learning of facial expressions is taken. The methodology is built upon Variational Autoencoders and eliminates the appearance-related features from the latent space by using neutral facial expressions as additional inputs. In order to improve the quality of the learned representation, we modify the prior distribution of the latent variable to impose the structure on the latent space that is consistent with human perception of facial expressions. We conduct the experiments on two datasets and the additionally collected similarity data, show that the human-like topology in the latent representation helps to improve the performance on the stereotypical emotion classification task and demonstrate the benefits of using a probabilistic generative model in exploring the roles of latent dimensions through the generative process.<br>Ansiktsuttryck spelar en viktig roll i områden som mänsklig kommunikation eller vid utvärdering av medicinska tillstånd. För att tillämpa maskininlärning i dessa områden skulle det vara fördelaktigt att ha en representation av ansiktsuttryck som bevarar människors uppfattning av likhet. I det här arbetet används ett data-drivet angreppssätt till representationsinlärning av ansiktsuttryck. Metodologin bygger på s. k. Variational Autoencoders och eliminerar utseende-relaterade drag från den latenta rymden genom att använda neutrala ansiktsuttryck som extra input-data. För att förbättra kvaliteten på den inlärda representationen så modifierar vi a priori-distributionen för den latenta variabeln för att ålägga den struktur på den latenta rymden som är överensstämmande med mänsklig perception av ansiktsuttryck. Vi utför experiment på två dataset och även insamlad likhets-data och visar att den människolika topologin i den latenta representationen hjälper till att förbättra prestandan på en typisk emotionsklassificeringsuppgift samt fördelarna med att använda en probabilistisk generativ modell när man undersöker latenta dimensioners roll i den generativa processen.
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Correia, J. Steve. "Agent-based target detection in 3-dimensional environments." Thesis, Monterey, California. Naval Postgraduate School, 2005. http://hdl.handle.net/10945/2300.
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Approved for public release, distribution is unlimited<br>Visual perception modeling is generally weak for game AI and computer generated forces (CGF), or agents, in computer games and military simulations. Several tricks and shortcuts are used in perceptual modeling. The results are, under certain conditions, unrealistic behaviors that negatively effect user immersion in games and call into question the validity of calculations in fine resolution military simulations. By determining what the computer-generated agent sees using methods similar to that used to generate the human players' screen view in 3- D virtual environments, we hope to present a method that can more accurately model human visual perception, specifically the major problem of a entity "hiding in plain sight"<br>Lieutenant, United States Navy