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Recently, watermarking has been modelled as communications with side information at the transmitter. The advantage of this is that in theory the interference due to the cover Work or host signal can be eliminated, thereby improving the capacity of the watermarking system. Hence a number of different practical methods have been proposed, one of which is based on dirty paper trellis coding. These codes are a form of spherical code, and as such, have the advantage of being robust to amplitude scaling. Dirty paper trellises have a number of design parameters. There is a lack of understanding on the influence of these parameters on performance, and this thesis attempts to address this. In particular, the thesis examines the following parameters: (i) the number of states and the number of arcs per state in the trellis, (ii) the distribution of the codewords generated by the trellis, and (iii) the cost function associated with each arc. Experimental results are provided on both synthetic signals and real images that demonstrate how performance is affected and a number of suggestions and improved designs are discussed. In particular, a deeper understanding of trellis configurations is provided that serves as a foundation on which to choose the best trellis structure based on bit error rate performance and computational cost. Secondly, trellis coded modulation (TCM) is adapted for use in a dirty paper trellis. This results in an improved distribution of the codewords on the sphere which leads to improved performance. Lastly, during embedding, the embedder usually searches for the codeword that has the highest linear correlation with the cover Work. However, this codeword may be difficult to embed due to perceptual constraints. We show that searching for a codeword that maximises a cost function based on linear correlation and perceptual distance can significantly improve performance.

This thesis examined the relationships of the conceptions of sport ability, achievement goals, and intrinsic motivation in Physical Education. Studies 1 and 2 investigated the psychometric properties of the Conceptions of the Nature of Athletic Ability Questionnaire (CNAAQ), a measure of sport ability beliefs. Results showed that the revised version of the scale possesses sound psychometric properties in assessing sport ability beliefs among children and youth. In addition, the relationships between ability beliefs, goal orientations, perceived competence, and behavioural indicators (intentions and amotivation) were also examined in the first two studies. An incremental belief predicted task orientation, whereas an entity belief predicted ego orientation. Intentions to be physically active were predicted by goal orientations indirectly through perceived competence, and directly by task orientation. In addition, amotivation was predicted directly and indirectly by ability beliefs and directly by achievement goals. Specifically, entity beliefs directly predicted amotivation, task orientation negatively predicted amotivation. Study 3 examined the interrelationships between ability beliefs, achievement goals, perceived competence, behavioural regulation, and arnotivation using cluster analysis. Five distinct clusters were identified based on these motivational constructs and these profiles were found to be related to perceived physical self-worth and levels of sport participation. Study 4 experimentally manipulated sport ability beliefs and examined their causal influence on achievement goals and motivation patterns when faced with failure. The causal link between ability beliefs and goals was supported. Ability attributions for failure were stronger for entity theorists compared to incremental theorists. However, hypotheses predicting differences on effort attributions, affective reactions, and behavioural markers were not supported. Study 5 examined the effects of goal involvement on enjoyment and intrinsic motivation under positive feedback. The results suggested that task-involved and ego-involved participants did not differ in self-reported enjoyment and free-choice behaviour measure. However, the free-choice behaviour of the ego-involved participants may not be fully intrinsically motivated. In addition, autonomous communication increased the positive effects of task and ego involvement on intrinsic motivation and enjoyment, whereas controlling communication had an undermining effect. Overall, results show that high incremental beliefs and high task orientation facilitate adaptive motivational patterns. Autonomy-supportive contexts also enhanced students' task motivation compared to controlling contexts.