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Facial expressions are visible signs of person's affective state, cognitive activity and personality. Automatic recognition of facial expressions is an important component for a wide spectrum of applications including human-computer interfaces, video conferencing, augmented reality and human activity monitoring to mention a few. Facial expression representation is an essential part in the automatic recognition of facial expressions. It is concerned with finding distinguishable features that can be utilised for representing different facial expressions without constraints of age, ethnicity or gender. This thesis reports on research and development in the facial expression representation. The author has proposed two novel methods for representing facial expressions. One is based on the shape space vector (SSV) of the statistical shape model (SSM); the other is based on the SSV of the B-spline statistical shape model (BSSM). The first proposed method uses the SSV of the SSM as a significant feature for representing facial expressions embedded in 3-D facial surfaces. In order to obtain the SSV, a novel model-based surface registration method is proposed that iteratively deforms and matches the model to an unseen new facial surface. Two major stages are included in this method, namely, model building and model fitting. In the model building stage, a SSM is built by using a training data set with estimated correspondences. In the model fitting stage, the built model is adapted to represent the shape of the new facial surface, which has not been included in the training data set. To build the model, the thin plate spline warping has been used so that all of the facial surfaces in the training data set are aligned into a common reference facial surface and the dense correspondences of points between these facial surfaces can be calculated. To fit the model to the new facial surface a modified iterative closest point (ICP) algorithm and least-squares projection on to the estimated shape space, constructed using the training data set, are applied. The second proposed method uses the SSV of the BSSM for facial expression representation. The mddel is built using B-spline control points instead of the surface points as in the SSM based method. In order to obtain the control points of B-spline, a novel method for the B-spline surface fitting has been proposed. The robustness and efficiency of both model-based facial expression representation methods are improved by introducing a multi-resolution scheme in the model fitting stage. The experimental results on simulated and real 3-D facial surfaces show that the proposed methods can effectively provide distinguishable features for facial expression analysis and recognition.

This thesis addresses the difficulty young children have making the transition from solving simple addition and subtraction problems with referential support to the formalised language of arithmetic ('what does one and one make?') (Hughes, 1981, 1986). Nine experiments are reported testing a total of 782 children between 4 and 5 years old on their use of strategic prompts in addition and subtraction. Results produced evidence for their significant positive impact, whether it be imagery, solving problems with their eyes closed or provision of a memory-check for the initial addend. Effectiveness was mainly on more difficult problems, particularly subtraction, with one mentalistic strategy generating results as effective as those using concrete referents. Five-and-a-half year old children were shown to have greater sensitivity overall to such prompts, whereas the younger children of around five years showed less sensitivity to the imagery-prompt, but like their older counterparts were most sensitive to prompts involving a memory-check. Referential support was also found to be effective when the older children were presented with written formal code notation. Furthermore, children were also found to be sensitive to implicit (rather than explicit) strategic prompts with child-initiated strategies, like 'fingers', most effective when chosen by the children themselves. Results are discussed in relation to how such explicit strategic prompts are effective, whether working directly or indirectly.

The role of imagery in language processing has received much recent attention. Paivio's two-process theory implies that concrete and abstract material are represented differently in memory. Specifically, concrete language is assumed to be retained in terms of an image which summarizes the meaning of the material in an integrated form. Abstract language, on the other hand, is assumed to be represented in a verbal-sequential form, with little integration of meaning. A review of the evidence on the effects of concreteness on memory for meaning indicates that Paivio's theory does not provide a completely adequate account of the results. In many of the studies which have produced findings consistent with the theory, an explanation in terms of differences in comprehensibility seems as appropriate as one based on different modes of storage. In addition, some studies have shown a substantial degree of semantic integration in abstract language. In an attempt to provide some clarification of this issue, a Levels of Processing model was proposed as an alternative to Paivio's theory. The model is based on the assumption that while abstract and concrete language typically differ in access to semantic processing, memory for meaning may be independent of concreteness under certain conditions. In particular, context may increase semantic processing in abstract language and thereby reduce the superiority of concrete language in memory for meaning which would otherwise be predicted. Two experiments were carried out to evaluate the model. In the first, the effect of concreteness, context, and presentation time on recognition of meaning and wording changes in sentences was investigated. The results supported the model in that memory for meaning relative to wording increased as a function of concreteness only when the sentences were presented in isolation from context. When the sentences were presented in the context of meaningful paragraphs, relative memory for meaning was equal in concrete and abstract material. The second experiment assessed the image-evoking capacity, comprehensibility, and degree of meaning change in test items, for the materials used in the first experiment. The results allowed several alternative interpretations of Experiment I to be discounted. In particular, Paivio's two-process theory was shown to be incapable of accounting for the elimination of the concreteness effect on memory for meaning as a function of context. It was concluded that the Levels of Processing model provides a more viable account of the role of imagery in language processing than Paivio's two-process theory. / Arts, Faculty of / Psychology, Department of / Graduate

This thesis explores the use of art, domestic, nature, religious and monetary imagery in the novel, The Ambassadors by Henry James.

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OBJECTIVE: Prior surgical studies have established functional neuroimaging as a validated method to examine brain activation patterns as well as distinctions between novice and expert surgeons during physical skills in surgery. The purpose of this study is to examine brain activation during cognitive surgical tasks. Our study utilizes simulated operative dictations to determine which brain regions are activated by this task and to distinguish different levels of expertise. METHODS: Junior residents (PGY 1-3), senior residents (PGY 4-5), and attendings were recruited for this study. Demographic questions and case characteristics were obtained. Participants sat in a quiet room and baseline measurements were taken. Then, they were tasked to perform a simulated operative dictation of a routine, open inguinal hernia repair utilizing the Lichtenstein technique. Three trials were completed with a two-minute rest between repetitions. Functional near-infrared spectroscopy (fNIRS) was used to measure brain activation during salient events of the operative dictation. Optode montage (developed during preliminary testing) covered prefrontal, occipital, and sensorimotor regions. Measurement of the fluctuations in deoxyhemoglobin and oxyhemoglobin concentrations during the cognitive task was obtained for each participant. Homer3 and AtlasViewer toolboxes were used to process raw data and changes in deoxygenated hemoglobin were evaluated relative to baseline. A general linear model (p < 0.05 and q < 0.05) was used to evaluate group-level differences. RESULTS: Ten participants were recruited for each group. Areas of increased and decreased brain activation were identified. Senior residents had significantly more activation in premotor areas, including supplementary motor area, parietal area, and right frontal area, compared to junior residents. Attendings demonstrated significantly less brain activation in medial frontal areas compared to the both junior and senior residents. CONCLUSION: Functional neuroimaging can examine cognitive functions during simulated operative dictations (a cognitive surgical task) and discern differences for various levels of expertise. This study is the first to connect mental imagery to neuroimaging analysis of cognitive function.

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