Thesis (Ph. D.)--University of Maryland, College Park, 2006. / Facsimile, authorized copy, from UMI/Proquest; UMI number 3222497. Includes bibliographical references. Also available on the internet.

I outline and defend a theory of mental representation based on three ideas that I extract from the work of the mid-twentieth century philosopher, psychologist, and cybernetician Kenneth Craik: first, an account of mental representation in terms of idealised models that capitalize on structural similarity to their targets; second, an appreciation of prediction as the core function of such models; and third, a regulatory understanding of brain function. I clarify and elaborate on each of these ideas, relate them to contemporary advances in neuroscience and machine learning, and favourably contrast a predictive model-based theory of mental representation with other prominent accounts of the nature, importance, and functions of mental representations in cognitive science and philosophy.

Thesis (M.S.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Vita. Bibliography: 115-118.

The e-government phenomena has become more important with the ever increasing number of implementations world wide. A model explaining the e-government adoption and the related measurement instrument a survey had been developed and validated in this study. In a post technology acceptance model (TAM) approach, theory of planned behavior (TPB) was extended to t the requirements of e-government context. The adoption of student loans service of the higher education student loans and accommodation association (KYK) was investigated to obtain data for empirical validation. The instrument was administered to over four-hundred students and partial least squares path modeling was employed to analyze the data. The results indicate that the model was an improvement over TAM in terms of predictive power. The constructs investigated in the study successfully explained the intention to use an e-government service.

Abstract The aim of this study was to create a mathematical model of the retinal nerve fiber layer and of the entire hill of vision, and to compare different perimetric methods and test grids in the detection of visual field loss in glaucoma and optic neuritis. A mathematical model of the retinal nerve fiber layer was developed, based on traced nerve fiber bundle trajectories extracted from 55 fundus photographs of 55 human subjects. The model resembled the typical retinal nerve fiber layer course within 20° eccentricity from the foveola. The standard deviation of the calculated corresponding angular location at the optic nerve head circumference ranged from less than 1° up to 18° (mean 8.8°). A smooth mathematical model of the hill of vision was created, based on 81 ophthalmologically healthy subjects. The model fit R2 was 0.72. Applying individually condensed test grids in 41 glaucomatous eyes of 41 patients enhanced remarkably the detection of progression. Seven out of 11 (64%) of the progressive scotomata detected by spatially condensed grids would have been missed by the conventional 6° × 6° grid. In 20 eyes of 20 patients with advanced glaucoma, the comparability of visual field areas obtained with semi-automated kinetic perimetry and automated static perimetry was satisfactory and within the range of the test-retest reliability of automated static perimetry. Using a standardized grid of 191 static targets within the central 30° visual field, the most common finding in 100 eyes of 99 patients with acute optic neuritis were central scotomas, accounting for 41% of all visual field defects in affected eyes. In conclusion, a model of the retinal nerve fiber layer was developed, which provided a detailed location specific estimate of the magnitude of the variability on the courses of retinal nerve fiber bundle trajectories in the human retina. A smooth mathematical model of the hill of vision with a satisfactory model fit was described for the 80° visual field. Individually condensed grids enabled the detection of a glaucomatous visual field progression more frequently and also earlier than conventional grids. Semi-automated kinetic perimetry was found to be a valuable alternative to automated static perimetry in monitoring advanced glaucomatous visual field loss. Using a grid with a higher spatial resolution may enhance the detection of small central visual field loss in optic neuritis.