Lau Wing Yin, Verena. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 74-78). / Abstract also in Chinese. / Acknowledgments --- p.2 / Abstract in English --- p.3 / Abstract in Chinese --- p.4 / Introduction --- p.5 / Major features of the Chinese language and processes in Chinese reading comprehension / Different paradigms in Chinese reading comprehension / Research questions of the present study / Research design of the present study / Experiment1 --- p.24 / Experiment2 --- p.32 / Experiment3 --- p.39 / General Discussion --- p.57 / Conclusion --- p.73 / References --- p.74 / Appendix A --- p.79 / Appendix B --- p.84

Gaze estimation systems determine where someone is looking. Gaze is used for a wide range of applications including market research, usability studies, and gaze-based interfaces. Traditional equipment uses special hardware. To bring gaze estimation mainstream, researchers are exploring approaches that use commodity hardware alone. My work addresses two outstanding problems in this field: 1) it is hard to collect good ground truth eye images for machine learning, and 2) gaze estimation systems do not generalize well -- once they are trained with images from one scenario, they do not work in another scenario. In this dissertation I address these problems in two different ways: learning-by-synthesis and analysis-by-synthesis. Learning-by-synthesis is the process of training a machine learning system with synthetic data, i.e. data that has been rendered with graphics rather than collected by hand. Analysis-by-synthesis is a computer vision strategy that couples a generative model of image formation (synthesis) with a perceptive model of scene comparison (analysis). The goal is to synthesize an image that best matches an observed image. In this dissertation I present three main contributions. First, I present a new method for training gaze estimation systems that use machine learning: learning-by-synthesis using 3D head scans and photorealistic rendering. Second, I present a new morphable model of the eye region. I show how this model can be used to generate large amounts of varied data for learning-by-synthesis. Third, I present a new method for gaze estimation: analysis-by-synthesis. I demonstrate how analysis-by-synthesis can generalize to different scenarios, estimating gaze in a device- and person- independent manner.

The traditional view of vision is that neurons in early cortical areas process information about simple features (e.g. orientation and spatial frequency) in small, spatially localised regions of visual space (the neuron's receptive field). This piecemeal information is then fed-forward into later stages of the visual system where it gets combined to form coherent and meaningful global (higher-level) representations. The overall aim of this thesis is to examine and quantify this higher level processing; how we encode global features in natural images and to understand the extent to which our perception of these global representations is determined by the local features within images. Using the tilt after-effect as a tool, the first chapter examined the processing of a low level, local feature and found that the orientation of a sinusoidal grating could be encoded in both a retinally and spatially non-specific manner. Chapter 2 then examined these tilt aftereffects to the global orientation of the image (i.e., uprightness). We found that image uprightness was also encoded in a retinally / spatially non-specific manner, but that this global property could be processed largely independently of its local orientation content. Chapter 3 investigated if our increased sensitivity to cardinal (vertical and horizontal) structures compared to inter-cardinal (45° and 135° clockwise of vertical) structures, influenced classification of unambiguous natural images. Participants required relatively less contrast to classify images when they retained near-cardinal as compared to near-inter-cardinal structures. Finally, in chapter 4, we examined category classification when images were ambiguous. Observers were biased to classify ambiguous images, created by combining structures from two distinct image categories, as carpentered (e.g., a house). This could not be explained by differences in sensitivity to local structures and is most likely the result of our long-term exposure to city views. Overall, these results show that higher-level representations are not fully dependent on the lower level features within an image. Furthermore, our knowledge about the environment influences the extent to which we use local features to rapidly identify an image.

1: Por este livro passam outros. 1.1: Que são teses e dissertações senão livros? 1.2: O livro como um lugar, não um livro objeto, mas enquanto meio, programa. 2: Um corpo cujo contorno renega seu papel continente, sempre apontando sua razão de existir para além de seus limites. 3: Uma aproximação mimética, na medida em que se utiliza das possibilidades dispostas, categorias e ítens sobressalentes de um dispositivo opaco: a nota de rodapé, o registro fotográfico, a escrita formatada, a descrição como maneira, a pretensão de distância reflexiva, a objetividade anunciada em resumos. 4: O resgate suspeitoso de um mito de origem: a inserção da produção de arte no campo de erudição acadêmico sem que a primeira tivesse de se submeter ao segundo, (daí a noção de hóspede tomada de Duchamp, e como consequência sua dimensão fantasmática). 3. 1: Costurar tudo pela narrativa de um sujeito que a um só tempo analisa, olha e é visto, predicado. 5: Manipular os dados, e por isso, admitir a manipulação como método científico. Então afirmar tudo como num Tratado. 3.2: Foi dado um aviso: \"descrever muitas vezes nos desobriga de explicar\". Mas veio demasiado tarde: já se havia optado, como estratégia, pela distração. 5. 1: Propor a leitura, implicada em sua ficção, de uma linha de pesquisa e o que esta guarda de específico - quem sabe um manual, no sentido de que o livro pode-se ter em mãos. Mas nem vale fazer caso desta introdução. Resumo nenhum abre mão de sua pretensão de roteiro conciso que dispensa o que finge anunciar, o parodiar de mais uma Tese. / If the images give in to the association urge that gives them impulse, without the bond that condemns them to the shroud of ordinate thought. If writing renounces the imposed duty of servant to the ideas. If the footnotes leak through the page, allowing the book\'s layout to breath. If translation is confronted by treason, we assume this treason as creation and books cease to disguise as mere support for content: \"By this book elapse others. What are thesis and dissertations, but books?\" What would then be necessary to grant this Thesis, despite its uncommon format, any trace of respectability? In different languages, the political pretensions which are close to us sound like the resume of a fairy tale: \"In a far a way University, ranked first amidst those from Cruzeiro do Sul, there is a singular line of research, understood by us as a place among others...\" But it might come handy since we still defend fictional grounds as something proper of our condition. A matter of resistance to the appropriation faced by our writings to strange purposes -- although our purpose itself might be the strange one. To quote academics as writers, to quote Bataille`s Story of the Eye and, without notice, to grant the story a scientific status. To quote fiction itself and the wealthiest concepts in the most readable way, keeping its improper spelling: Concept. And thinking in a pragmatic way, how glamorous wouldn\'t be a well formulated monograph -- extended linearly and permeated with reflections proper to its medium -- named with an easily translatable title: Thesis as Site?

Informationsskärmar återfinns idag på en mängd olika platser: i butiker, bibliotek, buss- och tågterminaler och liknande. Informationsskärmar är på frammarsch och spås bli en ännu vanligare syn framöver. Oftast är dessa skärmar helt statiska, det vill säga det går inte att interagera med dem och i de fall de tillåter interaktion handlar det främst om pekskärmar. Pekskärmstekniken har dock vissa tillkortakommanden och det finns ett behov av att undersöka nya sätt att interagera med datorer och informationsskärmar. En teknik som funnits länge i olika former men fram tills nyligen varit relativt otillgänglig för vanliga konsumenter är eye tracking (ögonspårning), en teknik för att spåra ögonrörelser hos människor.Syftet med denna uppsats är att undersöka hur eye tracking kan kombineras med en informationsskärm. Denna uppsats inriktar sig i första hand på hur detta kan användas för kommersiella ändamål; närmare bestämt eye tracking och informationsskärmar i ett slags reklamsammanhang. Detta har innefattat konstruerandet av en prototyp i form av en applikation som illustrerar reklam av en produkt i vilken användare kan få fram information om själva produkten bara genom att titta på dess olika delar. Iterativa tester har därefter genomförts där testdeltagare interagerat med två separata applikationer genom eye tracking. Testdata från dessa tester har tillsammans med teori främst från HCI-området använts för analysering och till sist har en slutsats presenterats.Studien visar att eye tracking har mycket stor potential att vara användbart tillsammans med informationsskärmar men att vissa utmaningar kvarstår med tekniken. Studien redogör även för dessa utmaningar och även möjligheter som finns med eye tracking. Slutligen presenteras även förslag till framtida forskning inom området som kan vara av intresse för dess fortsatta utveckling som HCI-teknik. / Program: Systemvetarutbildningen

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 68-69. / by Mark Johnson. / M.S.

Este trabalho apresenta uma metodologia de cálculo para a obtenção de doses em estruturas do olho humano, como: esclera, coróide, retina, nervo óptico, corpo vítreo, câmara anterior, lente, além do tumor devido ao tratamento com placas oftálmicas. Construiu-se um modelo de olho humano com suas principais estruturas e dimensões fieis, além de um modelo matemático para uma placa de Co-60 e uma placa de sementes de I-125, levando-se em conta tamanho e disposição geométrica das fontes reais, com o código de Monte Carlo MCNP-4C. Esse modelo é capaz de calcular as distribuições de dose axiais e radiais para qualquer ponto do olho e para cada uma de suas estruturas. Construiu-se, também, um simulador de acrílico para o olho. Esse simulador é formado por uma esfera de acrílico fatiada em lâminas de 1 mm de espessura para simular as mesmas condições de simulação realizada pelos código MCNP-4C, fornecendo as doses axiais e radiais em filmes radiográficos. O simulador foi utilizado para validar os cálculos realizados com o código MCNP-4C. Os dados obtidos desse modelo matemático servirão para montar um banco de dados de doses para todas as estruturas do olho, posições e tamanhos de tumores e quaisquer placas oftálmicas utilizadas para tratamento. Esse banco de dados será a parte principal para a construção de um “software" nacional para cálculos de dose, que poderá fazer parte de um sistema de planejamento confiável para ser utilizado em radioterapia/braquiterapia. / This work presents a calculational methodology for dose determination in human eye structures, such as: sclera, choroid, retina, lens, vitreous body, optic nerve and disc, and cornea, as well as tumor due to treatment to the eye plaques. A human eye model was constructed taking into consideration its main structural and dimension characteristics. Beyond that a mathematical model for the Co-60 and I-125 plaques with all geometric details were built employing the MCNP-4C code. This model is able to calculate the axial and radial doses in any point of the eye and for each of its structures. An acrylic eye simulator was also built with the aim to obtain experimental results for the both model validations. This simulator is made of an acrylic sphere split into foils of 1 mm thickness which allow the introduction a radiographic film to measure the axial and radial doses. The experimental data were used to validate the MCNP-4C results. The data from the mathematical model will serve as the basis to build a data bank for all the eye structures allowing different position and sizes of tumor as well as the replacement of all ophthalmic plaques used in the treatment. This data bank will be the principal part for the construction of a national software for the dose calculation and can be of great help for a reliable treatment system planning in radiotherapy/brachytherapy.

Many models of reading include cognitive components such as memory and attention in addition to the linguistic processing aspects; however, the particular effects of these other resources have yet to be clearly defined. The current study seeks to look at the effects of attentional resource manipulation on the reading process through the use of comic viewing, auditory distraction and dual-task paradigms. The study uses both behavioral measures (comprehension question performance) and eye-tracking measures (fixation time, revisits) to investigate the effects of increased cognitive load on the reading process in healthy, literate adults. The study found that healthy adults used the presence of comics to attenuate the effects of distraction and increased cognitive load on the comprehension process. Without the additional visual information of the comics, the participants showed a significant increase in the number of attempts to reread material (i.e. revisits) due to the distractor/dual-task presentation while still exhibiting notable decreases in comprehension. Furthermore, additional correlations were found between several cognitive testing measures and the participants’ performances in both the comprehension and eye-tracking measures across conditions. The results of this study provide valuable insight into future stages of this study, informing further research with both healthy adults and clinical populations such as people with aphasia or traumatic brain injuries.

Retinal degenerative diseases cause varying degrees of irreversible vision loss in millions of people worldwide. Common to all retinal degenerative diseases is the malfunction or demise of photoreceptor cells or its supportive cells, retinal pigment epithelium cell in the retina. A considerable part of these diseases were resulted from the inherited mutations of essential genes expressed in these retinal cells. The understanding of pathologic mechanism as well as developing of therapeutic treatment for these diseases were discussed in this study. A cutting-edge therapeutic genome editing technology is studied in the first part of study. This technology was invented to treat retinitis pigmentosa via engineered nucleases, which has great clinical potential for autosomal dominant genetic disorders that were previously irreparable by conventional gene therapy interventions. Though customizable gene editing tools can be engineered to target specific mutation sites, however it is too daunting for diseases like retinitis pigmentosa, a progressive retinal degenerative condition associated with more than 150 mutations in the rhodopsin gene alone. Here in this study, we present an “ablate-and-replace” combination strategy that 1) destroys expression of the endogenous gene by CRISPR/Cas9 in a mutation-independent manner, and 2) enables expression of wild-type protein through exogenous cDNA. As proof of concept, we show that our CRISPR-based therapeutic machinery efficiently ablates mRho in vivo, and when combined with gene replacement therapy, ameliorates rod photoreceptor degeneration and improves visual function in two genetically distinct autosomal dominant retinitis pigmentosa animal models. This mutation-independent, ablate-and-replace strategy represents the first electrophysiological recovery by a CRISPR-mediated therapy in an autosomal dominant disorder and it offers a clinically relevant, universal strategy to overcome allelic heterogeneity in debilitating inherited conditions. For the second part of the study, gene editing technology was used to study the pathogenesis of Doyne honey comb dystrophy, another Mendelian disease with extensive similarities to age-related macular degeneration. This monogenic disorder is caused by a unique point mutation on an extracellular matrix protein EFEMP1, expressed by retinal pigment epithelium cell. To precisely gauge the physiological effect resulted from this mutation, CRISPR-mediated gene correction was used to create isogeneic cell pairs from patient donated tissue-derived stem cells. These stem cells were differentiated into retinal pigment epithelium cell before analysis. We found unfolded protein response and immune response were not involved in the pathogenesis, which contradicts existing theories. Via proteomics analysis, we found expression level of a cholesterol catabolic enzyme was affected by the EFEMP1 mutation while those proteins controlling the cholesterol transport remains constant. This result provides supportive evidence to explain the aberrant intracellular accumulation of cholesterol found in patient retinal pigment epithelium cells. This imbalance in lipid homeostasis also suggests Doyne honey comb dystrophy is a retinal pigment epithelium cell-autonomous disease.

A concussion can result in a wide range of signs and symptoms including physical, cognitive, emotional and sleep-related symptoms. While a concussion can occur at any age, children and adolescents are at an increased risk of experiencing a concussion. Important physical consequences of concussion are balance deficits which affect approximately one in three cases. Balance is essential to perform many postures and activities and therefore it is important to accurately identify these deficits at the time of injury and during the recovery process in order to avoid potential further injury. A review of the literature regarding the different clinical and laboratory measures used to assess balance following a concussion was completed and identified several gaps in the literature. The four studies in this thesis were tailored to address these gaps in knowledge. The first study addressed the sensitivity of a gold standard clinical measure and laboratory measures of standing balance in terms of identifying balance deficits in adolescents at 1-month post-concussion. Performance on the Balance Error Scoring System (BESS) and COP measures from single and dual-task balance conditions were compared between a group of adolescents at one-month post-concussion and a group of non-injured adolescents. The results demonstrated that COP measures from single and dual-task conditions identified balance deficits in the concussed group that were not captured by the BESS. The second study addressed whether self-reported balance problems are a suitable alternative to COP measures to identify balance deficits in concussed adolescents. A secondary analysis of the data from study 1 was conducted to compare COP measures from the single and dual-task conditions between concussed adolescents self-reporting balance problems, concussed adolescents self-reporting no balance problems and a group of non-injured adolescents. The results from this analysis showed that the concussed adolescents demonstrated balance deficits regardless of whether they self-reported balance problems. There is significant clinical interest that lies in the ability to predict which adolescents presenting in the emergency department with concussion will be affected with ongoing balance deficits. The third study addressed the predictive ability of a set of COP variables recorded within the first 10 days following injury in a group of concussed adolescents to predict balance performance on a dual-task condition at one-month post-injury. Seven COP variables were identified as significant predictors. A secondary objective of this study was to compare performance on the COP measures between the concussed adolescents and a group of non-injured adolescents during the first session within the first 10 days following injury and during the second session at one-month post-injury and to compare performance between sessions within each group. The between session comparisons showed that performance remained relatively stable across sessions within both groups. In contrast, the between group comparisons revealed several significant differences in COP measures between the concussed and non-injured groups. The fourth study in this thesis addressed the association between balance and saccadic eye movements in concussed adolescents. Impaired saccadic eye movements are an important consequence of concussion and may be associated with balance deficits since both processes are dependent on several of the same cortical structures and brainstem areas. In this study, concussed and non-injured adolescents performed three different dual-task balance conditions involving either a high cognitive load, a low cognitive load and a gaze shifting component or a high cognitive load and a gaze shifting component. The results demonstrated that the concussed adolescents swayed over larger 95% ellipse areas while performing the two dual-tasks with the gaze shifting component, but these larger amounts of sway were not associated with an increase in saccades. Taken together, these four studies extend the current knowledge regarding balance performance in concussed adolescents and provide results that can be applied to balance assessments for concussion.