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 double immunolabelling technique was developed to study microscopically the interactions between CD4, CD45 and the T cell receptor on the surface of rat T cells induced by the phenomenon of co-capping. It was found that both CD4 and CD45 passively co-cap with the actively capped T cell receptor, that the T cell receptor and CD45 passively co-cap with CD4, but that neither CD4 nor the T cell receptor co-cap with CD45. Co-crosslinking and active capping of CD45 with either the T cell receptor or CD4 prevented CD4 or the T cell receptor respectively, from passively co-capping. These experiments were extended to study the effects of particular antibody crosslinking conditions on T cell proliferation and tyrosine phosphorylation. A correlation was found to exist between receptor distribution and the effects of particular antibody combinations on proliferation and tyrosine phosphorylation. The significance of this with respect to T cell activation is discussed. Finally, an observation is reported concerning the failure of some cell lines to cap antibody-crosslinked surface molecules. Preliminary investgations into the nature and extent of the phenomenon are described.

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.

The search for alternative energy resources began early in this century after the discovery of crude oil, but in 1973, when crude oil prices dramatically increased, the search for new energy sources intensified. The conservation of oil consumption, mainly in industrial countries has been more strictly applied, due to the limited quantities of fossil fuels, especially crude oil which is expected to be depleted within the next few decades. Moreover, the increasing level of air pollution and its severe consequences on human, animal, and plant life and climate, has forced the world to try to reduce air pollution emissions in the short-run, and to search for more reliable, renewable energy resources. Amongst renewable energy resources, solar energy has attracted much attention due to its unique characteristics, including its wide availability in huge quantities, particularly at the middle latitudes, its relatively simple harnessing compared with nuclear energy, and most importantly, its clean source which does not discharge any pollution emission. The intensity of solar radiation in Saudi Arabia reaches an average of 290 wm-2, one of the highest insolation values in the world. Here attention has been focused on solar energy as the main alternative sources of power. However, there is a great variation in the distribution of incoming solar radiation within Saudi Arabia. This variation is attributed mainly to six major factors. They include the following: 1. Sunshine duration 2. Insolation index 3. Altitude of the station 4. Specific humidity 5. Cloud cover, and 6. Dust storms. In order to measure the effect of each factor mentioned above on the variation of incoming solar radiation, a multiple linear regression model is developed and used. This is the most appropriate method to explain the interrelationships between the determinants and their dependent variable. In addition to the physical factors, the human factor is considered in this thesis as a result of the crucial effect of the perspectives and attitudes of people upon solar energy development. Therefore, a questionnaire was conducted at Al-Uyaynah Village, northwest of Riyadh, which has a solar-generated electricity in Saudi Arabia.

The work presented in this thesis describes a solution monitoring system that has been developed to assist United Nations' inspectors performing nuclear materials safeguards, primarily pertaining to plutonium storage and nuclear fuel reprocessing facilities. Based on the concept of the 'event', which is essentially any process that occurs on the plant, it aims to construct a hypothesis of which events have actually occurred, and to decide if any of these have safeguards implications. The package developed is robust, portable, and easy to use. The system has been implemented in G2 with extensive call-outs to FORTRAN and C routines. Sensor data from the plant is first analysed, and salient features (sub-events) are extracted. A model based diagnostic algorithm is then used to determine all possible causes of these sub-events; based on topographical knowledge of the plant, this makes extensive use of a simulation model. A rule based system then examines permutations of these sub-events and diagnoses, to find all possible events which could explain the data. From the possibilities generated, the most likely events are chosen on the basis of user specified subjective probabilities and on supporting evidence; these probabilities reflect the view that some events are more likely to be acceptable to the operator than others. Bayesian evidential updating methods are used to achieve this. An automatic model generator is presented, which extends the portability and applicability of the diagnostic aid, and makes implementation a great deal easier. Amongst other things, this enables simulations to be constructed automatically using a library of unit process models. The nature and forms of the various user interfaces are discussed. In particular facilities are available for creating and maintaining databases of rules which are used to identify, classify and rank the events. The system has been tested using data from a number of plants, both hypothetical and real. The primary test facilities have pertained to plutonium nitrate solution storage areas. A hypothetical solvent-extraction and concentration facility has also been considered, to extend the range of applicability of the system. These studies have demonstrated that solution monitoring has the potential to be a valuable aid for inspectors responsible for nuclear materials safeguards.