With the advent of computer games, the Human Computer Interaction (HCI) community has begun studying games, often with the intention of uncovering useful information to inform the design of work-based software. However, most HCI research on computer games focuses on the use of game technologies, often overlooking the fairly large amount of classic game literature. Despite the potential importance of computer game studies in HCI, there is a lack of frameworks that could guide such studies especially with regard to sociability. I believe that sociability is one of the most important criteria game developers may want to apply to game design as computer games are becoming more socialoriented due to the inception of the Internet. Therefore, the main aim of the thesis is to develop a play activity framework with an emphasis on social interactions. To achieve this, first, a comprehensive body of game literature was reviewed as a step to provide a solid foundation for the construction of the framework. Through the extensive review of literature, I chose Activity Theory as the foundation for the framework development. In order to demonstrate the applicability of Activity Theory in analysing computer-mediated social interactions, an exploratory study of online activities in a game community was conducted. Then, two studies were undertaken to formulate the framework by modelling play activities in the social game context. The first study was centred on the individual and collective play activities that take place within the game virtual world. The second study focused on games as a whole participatory culture, in which playing games is not just confined to within the game space but also includes other playful activities governed by norms and specific identities around the game. Through these studies, a play activity framework consisting of three play mode/s was developed: intrinsic, reflective and expansive play models, which are inter-related. The framework provides a vocabulary to describe the component, the motivation and the process of game play. The framework was then operationalised into methodological guidelines with a set of heuristic questions grouped into different categories. The guidelines were applied to analyse two issues, namely community building and social learning, in a Massively Multi-player Online Game (MMOG). As a conclusion, the framework has expanded conventional game studies by emphasising the socio-cultural context. It provides a different perspective on analysing computer games particularly the social aspects of gaming. Game researchers could use the framework to investigate play activities within and beyond the game and how they are related. The framework offers a theoretical explanation of various social activities observed in computer games. Finally, the methodological guidelines derived from the framework are useful as they give directions to analyse play activities particularly social interactions and game communities.

Little information is available in the literature concerning an ergonomic systems view of industrial seats. This study has been aimed at expanding knowledge of industrial seat design. For this purpose, a model for evaluating industrial seats has been proposed, listing demands and restrictions from the task and the workplace. It also includes responses and effects on the sitter, and methods of measurement for evaluating industrial work seats. The appropriateness of work seat design has been assessed in laboratory and field studies, using methods to measure body loads, their effects and responses. These have been body height shrinkage, biomechanical methods, subjective assessment, and posture assessment. The shrinkage method, including equipment and procedures, has been developed in this project. It assesses the effect of loads on the spine in vivo by using body height changes as a measure of disc creep. The results are well correlated with spinal loads. The method is sensitive enough to differentiate between spinal loads of 100 N difference. The results are also related to the perception of discomfort. Biomechanical methods have been developed for calculating compressive, shear, and momental loads on the spine. Ratings of discomfort, body mapping, interviews, video recordings, and prototype equipment for the recording of head posture have also been used. The methods have been shown to be appropriate for seat evaluation. Work seats have been evaluated in different tasks, incorporating back-rests of different height, width and shape, conventional seat pans and sit-stand seats. It has been shown that advantageous chair features could be referred to each particular task. The tasks evaluated included forward force exertion (high backrests advantageous), vision to the side (low backrests advantageous), work with restricted knee-room (seats allowing increased trunk-thigh angle advantageous), grinding (high, narrow backrests advantageous), punch press work (increased seat height advantageous), and fork lift truck driving (medium height backrest advantageous). The work task has been shown to be a major influence on seat design, and must therefore always be thoroughly considered.

Virtual Environments (VEs) created through Virtual Reality (VR) technologies have been suggested as potentially beneficial for a number of applications. However a review of VEs and VR has highlighted the main barriers to implementation as: current technological limitations; usability issues with various systems; a lack of real applications; and therefore little proven value of use. These barriers suggest that industry would benefit from some structured guidance for developing effective VEs. To examine this ‘training’ was chosen to be explored, as it has been suggested as a potential early use of VEs and is of importance to many sectors. A review of existing case studies on VE training applications (VETs) examined type of training applications and VR systems being considered; state of development of these applications and results of any evaluation studies. In light of these case studies, it was possible to focus this work on the structured evaluation of training psycho-motor skills using VEs created by desktop VR. In order to perform structured evaluation, existing theories of training and evaluation were also reviewed. Using these theories, a framework for developing VETs was suggested. Applying this framework, two VETs were proposed, specified, developed and evaluated. Conclusions of this work highlighted the many areas in the development process of an effective VET that still need addressing. In particular, in the proposal stage, it is necessary to provide some guidance on the appropriateness of VET for particular tasks. In the specification and building stages, standard formats and techniques are required in order to guide the VE developer(s) in producing an effective VET. Finally in the evaluation stage, there are still tools required that highlight the benefits of VET and many more evaluation studies needed to contribute information back to the development process. Therefore VEs are still in their early stages and this work unifies existing work in the area specifically on training and highlights the gaps that need to be addressed before widespread implementation.

This thesis is concerned with the investigation of hyperheuristic techniques. Hyperheuristics are heuristics which choose heuristics in order to solve a given optimisation problem. In this thesis we investigate and develop a number of hyperheuristic techniques including a hyperheuristic which uses a choice function in order to select which low-level heuristic to apply at each decision point. We demonstrate the effectiveness of our hyperheuristics by means of three personnel scheduling problems taken from the real world. For each application problem, we apply our hyperheuristics to several instances and compare our results with those of other heuristic methods. For all problems, the choice function hyperheuristic appears to be superior to other hyperheuristics considered. It also produces results competitive with those obtained using other sophisticated means. It is hoped that - hyperheuristics can produce solutions of good quality, often competitive with those of modern heuristic techniques, within a short amount of implementation and development time, using only simple and easy-to-implement low-level heuristics. - hyperheuristics are easily re-usable methods as opposed to some metaheuristic methods which tend to use extensive problem-specific information in order to arrive at good solutions. These two latter points constitute the main contributions of this thesis.

This thesis describes an anthropometric and biomechanical computer model of man which is an integral part of the SAMMIE workplace and work task design system. Some aspects of the design process have been studied, especially with respect to the inclusion of human factors in the design process via the medium of computer graphics. A satisfactory way of achieving this objective is seen as being the provision of a pictorial model of man which facilitates the evaluation of important ergonomic design criteria concerned with the problems of reach, fit, movement patterns, strength, fatigue, comfort and balance. A description is given of how such a model has been built, and linked with a similar model of the workplace to provide an integrated design and evaluation package.

A highly sensitive transverse susceptometer has been developed for the investigation of magnetic recording media. The susceptometer was based on the design of Pareti and Turilli[4] with modifications to the solenoid and sensing coils. The modifications have resulted in an improvement in the signal to baseline ratio of a factor of 525, and a reduction in random noise. The increase in the sensitivity of the susceptometer allowed the investigation of Advanced Metal Particle (AMP) tapes and the measurement of the imaginary component of the transverse susceptibility (TS) proposed by Papusoi[5]. Also, a modification was developed which allowed the investigation of the non-linear TS, proposed by Chantrell et al[7]. The work reported for the latter two techniques was the first experimental demonstration of these measurements on magnetic recording media. Samples of Co-y-Fe203, Cr02, mixed y-Fe203 / Cr02 and AMP tapes were investigated, as were y- Fe201, Cr0 2 and AMP powders. The investigations suggested that the incoherent reversal mode was dominant in the systems containing Cr02, with coherent reversal dominant in the remaining systems. The anisotropy peaks measured using the non-linear IS were found to be less dependent on sample texture than those of the traditional linear measurement. In particular the anisotropy peaks of the non-linear TS for incoherently reversing systems appeared to be independent of texture and it was proposed that these were a direct measure of the anisotropy field distribution, although independent verification was not performed. The determination of magnetic coating thickness after Sollis and Bissell[6] was extended to allow the measurement of AMP tapes. A computer model was developed to investigate the error in the technique due to the particulate nature of the coating. The results of the model indicated that the error increased as coating thickness and volume packing fraction decreased. Correction factors were determined for MP3 and MP4 particle based systems. The detection of the imaginary component of TS and its close agreement with the theoretical predictions of Papusoi suggested that the dassification of TS as a 'stiffness' method of anisotropy field determination might be in error.

Even though the significance of interchannel crosstalk in multichannel microphone technique has been an issue of much debate in the field of sound recording, any effects on the perception of reproduced phantom images have not been investigated systematically. There is consequently no experimental data to which sound engineers can refer when attempting to control interchannel crosstalk in the design and application of multichannel microphone technique. It was therefore necessary to investigate the effects of such interchannel crosstalk in both the perceptual and the physical domains. Extant multichannel microphone techniques were reviewed, concentrating on their crosstalk characteristics. Findings from concert hall and room acoustics studies relating to the effects of early reflections, which might be the basis for understanding the perceptual effects of interchannel crosstalk, were also studied. The effects of interchannel time and intensity relationship and sound source type on the perception of stereophonic phantom image attributes were first examined in the context of two-channel stereophonic reproduction. The perceptual attributes of phantom sources affected by interchannel crosstalk in three- channel microphone technique were then elicited, and the effects of interchannel time and intensity relationship, sound source type and acoustic condition on the perception of those attributes were investigated. The effects of interchannel crosstalk on sound quality preference were also examined in both controlled and practical manners. Finally, following objective measurements of experimental stimuli, relationships were established between the perceptual and objectively measured effects of interchannel crosstalk. It was found that the most salient perceptual effects of interchannel crosstalk were an increase in source width and a decrease in locatedness. The relationship between interchannel time and intensity differences involved in the crosstalk signal was significant for both effects. The type of sound source was significant only for the source width effect whereas the acoustic condition was significant only for the locatedness effect. The source width increase was mainly influenced by the middle frequencies of crosstalk signals in a region of the spectrum around 1000Hz, at the onsets of the signal envelopes. The results of listener preference experiments suggested that the preference for interchannel crosstalk would depend on the spectral and temporal characteristics of sound source to be recorded rather than on the magnitude of interchannel crosstalk.

Knowledge is frequently invoked as an explanatory factor in the relationship between technology and development, yet seldom with reference to an explicit conception of knowledge and almost never with reference to contemporary epistemology. The result is a multiplicity of different and in some cases contradictory 'knowledge-based' approaches. At the same time, epistemology is undergoing significant developments that suggest promising directions of enquiry and collaboration with the social and natural sciences. Of particular interest are naturalistic and externalist perspectives in analytic epistemology, where an emerging programme can be discerned aimed at bridging the gap between philosophical and empirical study of the way in which we come to know the world. This project can be seen as part of such a programme, applying naturalistic epistemology to the field of development and technology as the basis of a more grounded and general theory with a range of empirical applications. It begins with a discussion of the philosophical position, identifying three core dimensions of knowledge, their normative features and the potential of technology to support and extend functioning on each dimension. This theory is shown to have close affinities with the capability approach developed by Amartya Sen and Martha Nussbaum, leading to the articulation of a generic theory of 'knowledge capability'. The second half of the project applies the general theory to a case study of Internet use among AIDS NGOs in the province of KwaZulu-Natal in South Africa, where HIV prevalence rates of 37.5% have been recorded and where response to the epidemic has been left largely to civil society. The knowledge dimensions of NGO AIDS work are explored and conclusions drawn about the interactions between technology use, existing capabilities and wider environmental factors in determining the degree to which technology can in this case be considered a knowledge tool.

The management of adverse events within organisations has become a pressing issue as the perceptions of risk continue to heighten. However the basic need for developing secure information systems has remained unfulfilled. This is because the focus has been on the means of delivery of information, i.e. the technology, rather than on the various contextual factors related to information processing. The overall aim of this research is to increase understanding of the issues and concerns in the management of information systems security. The study is conducted by reviewing the analysis, design and management of computer based information in two large organisations - A British national Health Service Hospital Trust and a Borough Council. The research methodology adopts an interpretive mode of inquiry. The management of information systems security is evaluated in terms of the business environment, organisational culture, expectations and obligations of different roles, meanings of different actions and the related patterns of behaviour. Findings from the two case studies show that an inappropriate analysis, design and management of computer based information systems affects the integrity and wholeness of an organisation. As a result, the probability of occurrence of adverse events increases. In such an environment there is a strong likelihood that security measures may either be ignored or are inappropriate to the real needs of an organisation. Therefore what is needed is coherence between the computer based information systems and the business environment in which they are embedded. In conclusion, this study shows that to resolve the problem of managing information systems security, we need to understand the deep seated pragmatic aspects of an organisation. Solutions to the problem of security can be provided by interpreting the behavioural patterns of the people involved.

This thesis is concerned with the development and analysis of a non-linear approach to modelling and control of the contraction of electrically stimulated skeletal muscle. For muscle which has lost nervous control, artificial electrical stimulation can be used as a technique aimed at providing muscular contraction and producing a functionally useful movement. This is generally referred to as Functional Electrical Stimulation (FES) and is used in different application areas such as the rehabilitation of paralysed patient and in cardiac assistance where skeletal muscle can be used to support a failing heart. For both these FES applications a model of the muscle is essential to develop algorithms for the controlled stimulation. For the identification of muscle models, real data are available from experiments with rabbit muscle. Data for contraction with constant muscle length were collected from two muscle with very different characteristics. An empirical modelling approach is developed which is suitable for both muscles. The approach is based on a decomposition of the operating space into smaller sub-regions which are then described by local models of simple, possibly linear structure. The local models are blended together by a scheduler, and the resulting non-linear model is called a Local Model Network (LMN). It is shown how a priori knowledge about the system can be used directly when identifying Local Model Networks. Aspects of the structure selection are discussed and algorithms for the identification of the model parameters are presented. Tools of the analysis of Local Model Networks have been developed and are used to validate the models. The problem of designing a controller based on the LMN structure is discussed. The structure of Local Controller Networks is introduced. These can be derived directly from Local Model Networks. Design techniques for input-output and for state feedback controllers, based on pole placement, are presented. Aspects of the generation of optimal stimulation patterns (which are defined as stimulation patterns which deliver the smallest number of pulses to obtain a desired contraction) are discussed, and various techniques to generate them are presented. In particular, it is shown how a control structure can be used to generate optimal stimulation patterns. A Local Controller Network is used as the controller with a design based on a non-linear LMN model of muscle. Experimental data from a non-linear heat transfer process have been collected and are used to demonstrate the basic modelling and control principles throughout the first part of the thesis.