Intelligent virtual characters are becoming increasingly popular in en­ tertainment, educational and simulation software. A virtual charac­ ter is the creation or re-creation of a human being in an image, using computer-generated imagery. It must act and react in the environment, drawing on the disciplines of automated reasoning and planning. Creating characters with human-like behaviours that respond interactively to a real person in a video, is still a serious challenge. There are several major reasons for this. First, human motion is very complex, which makes it particularly difficult to simulate. Second, the human form is also not straightforward to design due to the large number of degrees of freedom of the motion. Third, creating novel contextual movements for virtual characters in real time is a new research area.

The H.264/MPEG-4 Advanced Video Coding (AVC) standard is a high efficiency and flexible video coding standard compared to previous standards. The high efficiency is achieved by utilizing a comprehensive full search motion estimation method. Although the H.264 standard improves the visual quality at low bitrates, it enormously increases the computational complexity. The research described in this thesis focuses on optimization of the computational complexity on H.264 scalable and multiview video coding. Nowadays, video application areas range from multimedia messaging and mobile to high definition television, and they use different type of transmission systems. The Scalable Video Coding (SVC) extension of the H.264/AVC standard is able to scale the video stream in order to adapt to a variety of devices with different capabilities. Furthermore, a rate control scheme is utilized to improve the visual quality under the constraints of capability and channel bandwidth. However, the computational complexity is increased. A simplified rate control scheme is proposed to reduce the computational complexity. In the proposed scheme, the quantisation parameter can be computed directly instead of using the exhaustive Rate-Quantization model. The linear Mean Absolute Distortion (MAD) prediction model is used to predict the scene change, and the quantisation parameter will be increased directly by a threshold when the scene changes abruptly; otherwise, the comprehensive Rate-Quantisation model will be used. Results show that the optimized rate control scheme is efficient on time saving. Multiview Video Coding (MVC) is efficient on reducing the huge amount of data in multiple-view video coding. The inter-view reference frames from the adjacent views are exploited for prediction in addition to the temporal prediction. However, due to the increase in the number of reference frames, the computational complexity is also increased. In order to manage the reference frame efficiently, a phase correlation algorithm is utilized to remove the inefficient inter-view reference frame from the reference list. The dependency between the inter-view reference frame and current frame is decided based on the phase correlation coefficients. If the inter-view reference frame is highly related to the current frame, it is still enabled in the reference list; otherwise, it will be disabled. The experimental results show that the proposed scheme is efficient on time saving and without loss in visual quality and increase in bitrate. The proposed optimization algorithms are efficient in reducing the computational complexity on H.264/AVC extension. The low computational complexity algorithm is useful in the design of future video coding standards, especially on low power handheld devices.

This study analyses the processes of agricultural and rural restructuring that have characterised rural economies since the end of the Second World War, leading to a reorientation from productivist to more entrepreneurial models of farming. In particular, the transition from the conventional role of the farmer as price taker, which requires appropriate technical and managerial competency, towards that of price maker, which calls for broader entrepreneurial competencies is highlighted. This transition is explored in the context of farm tourism, identified as a diversification strategy to promote a more sustainable rural economy and to protect farm incomes against market fluctuation. To date, the literature on farm tourism has overlooked many of these processes and whilst conceptualising the farmer as an entrepreneur, has not sufficiently engaged with key theories of entrepreneurship or indeed emergent frameworks of entrepreneurial skill and competency. The research draws on a mixed-method’s approach, which includes two distinct research phases conducted in the North West of England. In the initial phase, a survey of 118 diversified farm tourism businesses identifies that whilst the primary motivation to diversify is to provide additional household income, these farmers value business and management competencies at the expense of entrepreneurial competency. Thus, this initial phase, challenges the extent to which farmers are currently entrepreneurial in the context of the rural and agricultural restructuring highlighted. At the second research phase, utilising Q Methodology, a technique designed for the systematic study of subjectivity, a 42-item instrument developed from the extant literature on entrepreneurial competence was administered to 15 farm tourism entrepreneurs. The Q analysis identifies three distinct perspectives on entrepreneurial skill and competency which farmers identify as necessary for successful diversification, termed: the Reflective Leader, the Opportunity Aware Organiser and the Opportunity Driven Innovator. The main characteristics of these groups are discussed and provide the basis for a taxonomy of the farmer as a rural tourism entrepreneur. Moreover, the results reveal the heterogeneity of diversified farmers in the study region, which encapsulates a wide range of perspectives from the risk averse to the opportunity aware, from the managerial to the entrepreneurial The thesis concludes by presenting a conceptual model of entrepreneurial competency, as well an additional taxonomy which classifies the farmer as a rural entrepreneur within a broad landscape of farming identity. The work thus provides a better understanding of farm tourism and a valuable insight into the complexity of rural and farm tourism entrepreneurship. As well as suggestions for future research, the findings will be of interest to academics and policy actors, with the conclusions providing a foundation to better understand farm diversification. Insights that may better inform rural business support, training and advisory services and foster critical policy discussion and debate.

The games industry has developed online multiplayer three-dimensional game worlds that allow players from different geographical locations to engage in competitive and cooperative gameplay together. This has enabled players from different cultures to inhabit the same virtual game world, bypassing any geographical or cultural boundaries found in the real world. These 3D game worlds ask the player to use the basic principles of spatial awareness and movement from the real world, and are often virtual representations of real world environments. These spaces are designed for players from all nationalities to inhabit concurrently. There is now a need to determine design considerations for these multicultural multiplayer game worlds but any investigation must consider the historical evidence from the games industry of cultural differences in gameplay preferences. This thesis discusses the effect of cultural knowledge on the spatial design and interpretation of three-dimensional game environments that are based on real world affordances. A new methodology for the comparative analysis of the design of three-dimensional game environments is established using Space Syntax metrics. This facilitates the discussion of cultural models applied to design thinking for the implementation and interpretation of game environments. Through spatial metrics the analysis of the intelligibility underlying three-dimensional game environments is correlated to the imageability of the projected two-dimensional screen image. The application of this methodology to internationally popular, and culturally specific, game environments establishes new knowledge on tacit cultural influences within game design processes. The analysed intelligibility of the environments indicates cognitive differences between Eastern and Western cultures, already recognised in the interpretation of two-dimensional imagery, also exist within the design and interpretation of three-dimensional game spaces. This study establishes a new methodology through the analysis of intelligibility for design research into game environments. The resulting evaluation of tacit cultural influences within the design of the environments establishes new cultural differences and commonalities. These design characteristics can inform future game design methodologies within industry for the design and implementation of multicultural game environments.

A careful examination of the creative writing of T. S. Eliot reveals that his poetry can be divided for purposed of consideration into two phases. The first phase refers to those poems written up to and including "The Hollow Men". These early poems can best be grouped together and characterized by the term frustration. The poetry of the second phase, written after "The Hollow Man," is dominated by and best considered in regard to a quest for the ideal.

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The development of the nonlinear version of the Continuous-time Generalised Predictive Control (NCGPC) is presented. Unlike the linear version, the nonlinear version is developed in state-space form and shown to include Nonlinear Generalised Minimum Variance (NGMV), and a new algorithm, Nonlinear Predictive Generalised Minimum Variance (NPGMV), as special cases. Through simulations, it is demonstrated that NCGPC can deal with nonlinear systems whose relative degree is not well defined and nonlinear systems with unstable zero dynamics. Geometric approaches, such as exact linearisation, are shown to be included in the NCGPC as special cases.

Although human sustained control movements are continuous in nature there is still controversy on the mechanisms underlying such physiological systems. A popular topic of debate is whether human motor control mechanisms could be modelled as engineering control systems, and if so, what control algorithm is most appropriate. Since the early years of modelling sustained control tasks in human motor control the servomechanism has been an adequate model to describe human tracking tasks. Another continuous-time system model that is often used to model sustained control tasks is the predictive controller which is based on internal models and includes prediction and optimisation. On the other hand, studies have suggested intermittent behaviour of the ``human controller'' in sustained motor control tasks. This thesis investigated whether intermittent control is a suitable approach to describe sustained human motor control. It was investigated how well an intermittent control system model could approximate both the deterministic and non-deterministic parts of experimental data, from a visual-manual compensatory tracking task. Finally, a preliminary study was conducted to explore issues associated with the practical implementation of the intermittent control model. To fit the deterministic part of experimental data, a frequency domain identification method was used. Identification results obtained with an intermittent controller were compared against the results using continuous-time non-predictive and predictive controllers. The results show that the identified frequency response functions of the intermittent control model not only fit the frequency response functions derived from the experimental data well, but most importantly resulted in identified controller parameters which are similar to those identified using a predictive controller, and whose parameter values appear to be physiologically meaningful. A novel way to explain human variability, as represented by the non-deterministic part of the experimental data (the \emph{remnant}), was developed, based on an intermittent control model with variable intermittent interval. This model was compared against the established paradigm, in which variability is explained by a predictive controller with added noise, either signal dependent control signal noise, or observation noise. The study has shown that the intermittent controller with a variable intermittent interval could model the non-deterministic experimental data as well as the predictive controller model with added noise. This provides a new explanation for the source of remnant in human control as inherent to the controller structure, rather than as a noise signal, and enables a new interpretation for the physiological basis for human variability. Finally, the theoretical intermittent control model was implemented in real-time in the context of the physiological control mechanism of human standing balance. An experimental method was developed to apply automatic artificial balance of an inverted pendulum in the context of human standing, via functions electrical stimulation control of the lower leg muscles of a healthy subject. The significance of this study is, firstly, that frequency domain identification was applied for the first time with intermittent control, and it could be shown that both intermittent and predictive control models can model deterministic experimental data from manual tracking tasks equally well. Secondly, for the first time the inherent variability, which is represented by the remnant signal, in human motor control tasks could be modelled as part of the structure of the intermittent controller rather than as an added noise model. Although, the experimental method to apply automatic artificial balance of an inverted pendulum in the context of human standing was not successful, the intermittent controller was implemented for the first time in real-time and combined with electrical muscle stimulation to control a physiological mechanism.

Increasingly, people turn to the Internet for access to services, which often require disclosure of a significant amount of personal data. Networked technologies have enabled an explosive growth in the collection, storage and processing of personal information with notable commercial potential. However, there are asymmetries in relation to how people are able to control their own information when handled by enterprises. This raises significant privacy concerns and increases the risk of privacy breaches, thus creating an imperative need for mechanisms offering information control functionalities. To address the lack of controls in online environments, this thesis focuses on consent and revocation mechanisms to introduce a novel approach for controlling the collection, usage and dissemination of personal data and managing privacy ex- pectations. Drawing on an extensive multidisciplinary review on privacy and on empirical data from focus groups, this research presents a mathematical logic as the foundation for the management of consent and revocation controls in technological systems. More specifically, this work proposes a comprehensive conceptual model for con- sent and revocation and introduces the notion of 'informed revocation'. Based on this model, a Hoare-style logic is developed to capture the effects of expressing indi- viduals' consent and revocation preferences. The logic is designed to support certain desirable properties, defined as healthiness conditions. Proofs that these conditions hold are provided with the use of Maude software. This mathematical logic is then verified in three real-world case study applications with different consent and revocation requirements for the management of employee data in a business envi- ronment, medical data in a biobank and identity assurance in government services. The results confirm the richness and the expressiveness of the logic. In addition, a novel testing strategy underpinned by this logic is presented. This strategy is able to generate testing suites for systems offering consent and revocation controls, such as the EnCoRe system, where testing was carried out successfully and resulted in identifying faults in the EnCoRe implementation.

Le travail est constitué de deux chapitres qui ne sont pas liés entre eux. Dans le premier chapitre nous proposons une minoration de la hauteur canonique pour une certaine classe de modules de Drinfeld à caractéristique 0 exprimée en fonction de la dimension sur le corps de définition de ce module, des points algébriques (dans une opportune cloture algébrique) qui ne sont pas de torsion, en dévéloppant ainsi une étude du problème de Lehmer au cas des modules de Drinfeld. Dans le deuxième chapitre nous proposons une stratégie d’attaque à la conjecture de Manin-Mumford au cas des T-modules abéliens et uniformisables basée sur la méthode introduite par J. Pila et U.Zannier au cas des variétés abéliennes définies sur un corps de nombres. Nous proposons en particulier un premier pas dans une telle direction qui consiste à reprendre les travaux de J. Pila et J. Wilkie pour parvenir à une majoration du nombre des points de torsion d’un T-module qui respecte nos hypothèses, et qui puisse constituer un fondament essentiel au dévéloppement de cette méthode comme dans le cas classique. / We divide this work in two different chapters having no relation between them. In the first chapter we propose a lower bound estimate of the canonical height on a certain family of Drinfeld modules having characteristic 0, depending by the dimension of these Drinfeld module algebraic points on the base function field (into a well-chosen algebraic closure). This will take us to deeply analyze the Lehmer problem on Drinfeld modules. In the second chapter we propose a strategy to approach the Manin-Mumford conjecture on uniformizable abelian T-modules, based on the new techniques introduced by J. Pila and U. Zannier for abelian varieties defined on a number field. We propose in particular a first step in such a direction by a new interpretation of the J. Pila and J. Wilkie’s work in order to obtain an higher bound estimate on the number of torsion points of a such T-module. This would be an important basis to a future development of this method, as in the classic case.