Thesis (doctoral)--Rheinisch-Westfälische Technischen Hochschule Aachen, 1999. / Includes bibliographical references (p. 133-142).

Thesis (Ph. D.)--School of Electrical and Information Engineering, Faculty of Engineering, University of Sydney, 2001. / Title from title screen (viewed 13 January 2009). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Electrical and Information Engineering, Faculty of Engineering. Includes bibliographical references. Also available in print form.

The research reported here investigated the nature of young children's understanding of a novel symbol-a scale model. Children witnessed the hiding of a small toy in a scale model of a room and were then required to search for an analogous larger toy that had been surreptitiously hidden in the actual room. At issue was whether children succeed by attending to the target location (object strategy), to the spatial location of the target location (spatial strategy), or to both types of information. It has been suggested that at three years of age (the age at which children first succeed on the task) children succeed by recognizing the correspondence between analogous objects in the two spaces (Bence & Presson, 1997; Blades & Cooke, 1994; Perner, 1991; Lillard, 1993) but that an understanding of the model as a whole as a representation of the room necessitates also attending to the spatial relations between the objects (Perner, 1991; Lillard, 1993). In five Experiments, children participated in versions of the model task that varied in the type of information (object and/or spatial) available to solve the task. The results revealed that although, in general, children rely primarily on the identity of the individual objects to find the hidden toy, the spatial relations between the objects may also influence task success. Furthermore, there was strong evidence of individual differences in children's strategies which appeared to be linked to sex, with girls attending primarily to the identity of the objects and boys demonstrating a fledgling ability to approach the model spatially. Some children also appeared to label the target object but the labeling strategy could not account for girls' tendency to attend to the objects more than boys. It is suggested that characterizations of an abrupt shift between three and four years of age in the ability to interpret the model as a whole as a representation of the room may be misleading. There may be multiple developmental routes to the gradual acquisition of an explicit understanding of a scale model as a symbol for the space it is intended to represent.

Advisers: Terry Takahashi and Richard Marrocco. xiv, 152 p. / Neurons in the barn owl's inferior colliculus (IC) derive their spatial receptive fields (RF) from two auditory cues: interaural time difference (ITD) and interaural level difference (ILD). ITD serves to restrict a RF in azimuth but the precise role of ILD was, up to this point, unclear. Filtering by the ears and head insures that each spatial location is associated with a unique combination of frequency-specific ILD values (i.e., an ILD spectrum). We isolated the effect of ILD spectra using virtual sound sources in which ITD was held fixed for all spatial locations while ILD spectra were allowed to vary normally. A cell's response to these stimuli reflects the contribution of ILD to spatial tuning, referred to as an “ILD-alone RF”. In a sample of 34 cells, individual ILD-alone RFs were distributed and amorphous, but consistently showed that the ILD spectrum is facilatory at the cell's best location and inhibitory above and/or below. Prior results have suggested that an IC cell's spatial specificity is generated by summing inputs which are narrowly tuned to frequency and selective for both ILD and ITD. Based on this premise, we present a developmental model which, when trained solely on a cell's true spatial RF, reproduces both the cell's true RF and its ILD-alone RF. According to the model, the connectivity between a space-tuned IC cell and its frequency-specific inputs develops subject to two constraints: the cell must be excited by ILD spectra from the cell's best location and inhibited by spectra from locations above and below but along the vertical strip defined by the best ITD. To assess how frequency-specific inputs are integrated to form restricted spatial RFs, we measured the responses of 47 space-tuned IC cells to pure tones at varying ILDs and frequencies. ILD tuning varied with frequency. Further, pure-tone responses, summed according to the head-related filters, accounted for 56 percent of the variance in broadband ILD-alone RFs. Modelling suggests that, with broadband sounds, cells behave as though they are linearly summing their inputs, but when testing with pure tones, non-linearities arise. This dissertation includes unpublished co-authored materials.

Made available in DSpace on 2014-06-11T19:31:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-19Bitstream added on 2014-06-13T19:21:02Z : No. of bitstreams: 1 jesus_ea_dr_rcla.pdf: 2702571 bytes, checksum: b0bab90b066fc1518130aee0d0a71b2a (MD5) / A presente pesquisa foi desenvolvida na comunidade Kalunga, remanescente de antigos quilombos que se formaram na região norte do Estado de Goiás, precisamente limitados pelos municípios de Cavalcante, Teresina e Monte Alegre de Goiás. Tal comunidade tem mais de 250 anos de existência, de vida autônoma e de contato com as culturas da sociedade nacional. Sua escolha se deu pelo fato de se tratar de uma comunidade que vive fora dos padrões sociais condicionantes daquilo que, até pouco tempo, era conhecido como único modelo de “civilização”. Fundamentada nas teorias na Etnomatemática, que estuda as várias maneiras de explicar e de entender os distintos contextos naturais e socioeconômicos, diferenciados no tempo e no espaço, teve como objetivo principal descrever e analisar os múltiplos lugares e espaços onde está inserida a sua cultura e que são fundantes para a constituição do ser daquele povo. Embora tenha lançado um olhar limitado e a partir de referenciais eurocêntricos, buscamos compreender as dinâmicas produções de conhecimentos que se manifestam nas ações diárias que, em grande medida se enraíza nas tradições e, consequentemente, nas relações místico-sagradas. Pudemos perceber, a partir das observações, que os espaços construídos, baseados nas crenças e fortalecidos nas ocasiões de encontros sagrados, se projetam para os modos/maneiras de ver o mundo e de se situarem dentro dele; e se projeta para o entendimento e organização de seus lugares, o que nos permitiu interpretar de forma transcultural e holística acerca do que os saberes/fazeres representam para a construção do ser Kalunga. Usando as técnicas de caráter etnográfico, procuramos analisar o desenvolvimento dessa organização, levando em consideração seus aspectos históricos, sociais e circunstanciais / This research was performed in Kalunga community, reminiscent of old quilombos that formed in the northern state of Goias, precisely limited by the municipalities of Cavalcante , Monte Alegre and Teresina de Goiás This community has more than 250 years of existence, of life autonomous and contact with the cultures of national society. His choice was the fact that it is a community that lives outside the social standards of what conditions, until recently, was known as the only model of civilization. Based on theories in Ethnomathematics, who studies the various ways to explain and understand the different natural and socio-economic contexts, different in time and space, aimed to describe and analyze the multiple spaces and places where it is located and that their culture are a foundation for the constitution of that people. Although he released a limited look and from Eurocentric references, we sought to understand the dynamics of knowledge production that are manifested in the daily actions that are largely rooted in the traditions and, consequently, in the mystical and sacred relationships. We could see, from observations, that the built environment, based on the beliefs and strengthened in times of sacred meetings, project into the ways of seeing the world and are situated within it, which projects to the understanding and organization their places, in order to interpret cross- culturally and holistically about the knowing / doing to represent the construction of Kalunga be. Using ethnographic techniques, we analyze the development of the organization, taking into account its historical, social and circumstantial

Contrast sensitivity to vertically oriented grating patterns with a sinusoidal luminance profile were examined between groups of observers varying either in gender or age. For each observer at each of the seven spatial frequencies tested (.75, 1.5, 3, 6, 7.5, 10, 15 cyc/deg) threshold values were calculated for either ascending or descending trials as well as a combination of both. These threshold values were numerically transformed into sensitivity values and contributed to a group mean contrast sensitivity score for each spatial frequency. No significant effect of gender was found but younger observers (mean age=22.6 yrs.) exhibited significantly better contrast sensitivity than the older aged group (mean age=66.2 yrs.) for ascending trials at 3, 1.5 and .75 cyc/deg--the lowest spatial frequencies tested. Contrast sensitivity was also correlated with various measures. These findings were discussed in relation to the existing literature on age and spatial contrast sensitivity and since the machine used to examine the contrast sensitivity function (CSF) in this study utilized a laser interferometric method of stimulus generation, possible neurological changes with aging to explain this noted loss were also considered. Also discussed were various parameters that effect the CSF with a view toward explaining the disparate findings of various existing studies of age and the CSF. / Arts, Faculty of / Psychology, Department of / Graduate

The main purpose of this study was to examine the psychometric characteristics of the Bicycle Drawing Test. The 20-point scoring criterion was evaluated, and the preliminary norms were established. The Bicycle Drawing Test is an easily administered free-style drawing task that has been found to be a useful addition to a neuropsychological test battery. It provides a sample of visuopractic functioning involving the formation of a perceptual construct, a motor response, and a spatial component.

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