This thesis is concerned with the potential applications for in-cylinder ionisation probes for the feedback control of spark ignition engines. Such sensors are shown to yield useful qualitative information about the combustion process. Two different implementations of an in-cylinder ionisation probe are investigated - both types are demonstrated to have potential for specific control applications. The first implementation is a <i>Flame front sensor</i> - here an ionisation probe is used to determine the time of flame arrival at a position remote from the spark plug. This parameter is typically subject to a high degree of cyclic variability, but is generally sensitive to variables which affect the flame speed such as air/fuel ratio, turbulence characteristics etc. The flame arrival time is shown to be useful as an indicator of relative cylinder to cylinder variations. The general signal characteristics were determined for a range of engine conditions and a system for the real-time, feedback control of a fuel injection system was developed and demonstrated. Results showed that, with the controller implemented on a four cylinder engine, the lean misfire limit could be extended to higher air/fuel ratios and the brake specific fuel consumption was improved. The second implementation of a <i>Post-flame ionisation sensor</i> -- the residual ionisation in the burnt gases behind a flame front is used to provide a signal which is sensitive to cylinder temperature and pressure. The central electrode of the spark plug is conveniently located to produce such a signal -- providing precautions are taken to protect the signal circuitry from the high voltage ignition spark. The signal characteristics of the spark plug ionisation probe were evaluated. Applications of the signal to the feedback control of ignition timing and/or fuelling, based on the estimation of peak cylinder pressure arrival and knock intensity, are demonstrated.

Cellular manufacturing is an important approach to the organisation of production. Large benefits are claimed over traditional functional organisation, and it is compatible with prominent manufacturing theories, such as just-in-time, total quality management, and computer integrated manufacturing. Several very successful applications of cellular manufacturing have been reported, but a wide range of performance improvements has also been observed. Many benefits ofcellular manufacturing do not arise directly from changing the organisation and layout ofdirect production resources, but from changes to the way the production process is operated, managed and controlled, that are made possible by the cellular organisation. Underachievement occurs when companies do not identify and exploit such opportunities. This research aims to address the problem by providing a system wide concept of cellular manufacturing and an improved process to support the design of a cellular manufacturing system based on this concept. A review of the theory and practice of cellular manufacturing is presented. A model is proposed, which comprises a general set of mutually compatible, production system wide, production system features for supporting or exploiting self-contained groupings of manufacturing resources. A subset of the features from the general model will be appropriate to a particular application of cellular manufacturing. Current processes for designing cellular manufacturing systems do not adequately support the application of such a concept. In particular, tailoring the general concept ofcellular manufacturing to a specific situation is identified to be an important but widely neglected design activity. A process is defined that makes concept design explicit, and a matrix-based tool developed to relate the features of cellular manufacturing to a company's performance improvement objectives. The value ofthis novel approach to designing cellular manufacturing systems is determined to be in facilitating the generation and communication of insight into the nature ofcellular manufacturing, encouraging a comprehensive appraisal of the concept and its impact throughout the production system, and focusing limited resources where they will be most effective.

A popular approach to operating organizations in the 1990s is the implementation of work teams. The current literature offers little information on the use of performance management techniques in work team settings. This case study examined the effects of employing a performance improvement strategy on employee performance in a work team environment comprised of part-time graduate students. The performance improvement strategy included composing job descriptions, job aids (e.g., work organization charts), task request logs and posting weekly and monthly performance feedback. Improvements were observed in some aspects of team performance. Some of the improvement was due to task clarification and improved scheduling produced by the antecedent interventions. Performance feedback had little effect on measured performance but seemed to facilitate discussion and problem-solving.

Improving program performance through the use of multiple homogeneous processing elements, or cores, is common-place. However, these architectures increase the complexity required at the software level. Existing work is focused on optimising programs that run in isolation on these systems, but ignores the fact that, in reality, these systems run multiple parallel programs concurrently with programs competing for system resources. In order to improve performance in this shared environment, cooperative tuning of multiple, concurrently running parallel programs is required. Moreover, the set of programs running on the system – the system workload – is dynamic and rapidly changing. This makes cooperative tuning a challenge, as it must react rapidly to changes in the system workload. This thesis explores the scope for performance improvement from cooperatively tuning skeleton parallel programs, and techniques that can be used to cooperatively auto-tune parallel programs. Parallel skeletons provide a clear separation between algorithm description and implementation, and provide tuning knobs that the system can use to make high-level changes to a programs implementation. This work is in three parts: (i) how many threads should be allocated to each program running on the system, (ii) on which cores should a programs threads be executed and (iii) what values should be chosen for high-level parameters of the parallel skeletons. We demonstrate that significant performance improvements are available in each of these areas, compared to the current state-of-the-art.

No description available.

This project was inspired by a declaration made by built environment professionals at the World Summit on Sustainable Development (GABS, 2002), of the need for a common framework to improve decision making for sustainable development. Priori theorising indicated the suitability of governance as a topic of consideration and the possibility that a governance framework offered a potential solution. The research question was therefore: “would a governance framework for the built environment sector provide a framework in which decision making for sustainable development could be improved for all built environment stakeholders?” With an added dimension of testing for developed and developing countries, the research project was constructed on the case study methodology using the built environment sectors of the UK and Ghana. The project commenced with a review of literature which confirmed that governance is a core component of sustainable development and of increasing relevance to built environment stakeholders in both developed and developing countries. A significant gap in the literature concerning governance and the built environment sector was identified. Through analysis of literature a governance framework was constructed to act as the theoretical framework for testing. A comparative analysis of the current governance arrangements impacting on the built environment sectors in each of the case studies provided data to test the theoretical framework. A contingency valuation carried out with built environment policy makers and practitioners in Ghana provided data to further test the acceptability and applicability of the theoretical governance framework. It was concluded that a governance framework provided a robust framework in which decision making for sustainable development could be analysed and improved. Furthermore, evidence indicates that the completeness of a sector’s governance framework is a key indicator of performance for sustainable development in the built environment sector. The framework developed in this project has been used to analyse performance in Ghana’s built environment sector and the resulting policy guidance has informed the development of policy and institutional reforms in Ghana.

This thesis argues that caffeine use offered a survival advantage to our ancestors and that moderate use continues to offer modern humans benefits. Caffeine ingestion, through the blocking of adenosine receptors, elicits broad elements of the mammalian threat response, specifically from the ‘flight or fight’ and ‘tend and befriend’ repertoires of behaviour: in effect, caffeine hijacks elements of the stress response. If the effects of caffeine had been discovered recently, rather than being available to Homo sapiens since Neolithic hunter gatherer times, it is likely that caffeine would be considered a ‘smart’ drug. More caffeine is being ingested today than ever previously recorded. Caffeine use is found across all age groups, all socio-economic strata, most ethnic groups, and is being used increasingly by the medical and pharmaceutical industries and by the armed forces. Yet despite this wide usage and a substantial body of research literature, there is at present no clear pattern or plausible model for the way caffeine achieves its effects. There is much contradiction in the literature and ambiguity as to why caffeine use should improve performance on some tasks, impair it on others and have no effect on other tasks, for some but not all of the time. The present work argues, through an examination of the specificity of caffeine’s operation, that these effects are not arbitrary but elicited by the nature of the tasks, in particular that caffeine ingestion affects those processes and behaviours which improve the probability of survival under perceived threat or stress. This is argued through the perspective of evolutionary psychology and relies theoretically on Polyvagal Theory. The argument generates testable hypotheses and empirical support for the thesis is garnered from nine experiments on card-sorting, verbal and numerical processing, local and global categorization, field dependence-independence, the Stroop task, tests of visuo-spatial ability, and from a correlational study of caffeine use and personality traits. It is concluded that moderate caffeine use in healthy adults promotes behaviours likely to be adaptive under perceived threat or stress. Limitations of both theory and empirical work and are discussed, together with potential practical applications and suggestions for further work.

Purpose: This master thesis attempts to propose a guideline for improving logistics performance in terms of cost efficiency and on-time delivery in shipper-TPL provider relationships within offshore outsourcing businesses. Methodology: As a first step, the authors construct a conceptual model based on a thorough literature review. In a second step, empirical data is collected through semi-structured interviews within a single-case study with dyadic perspectives examining the shipper-TPL provider relationship of Ericsson, Sweden and Aramex, Saudi Arabia. Lastly, the authors are able to develop a final detailed model through merging the discovered theoretical and empirical findings. Findings: The findings of this thesis highlight the impact on performance of the factors of communication, culture, work agreements, standardization, system compliance and trust. Based on these factors, the PILOOR Model is developed that illustrates a sequential order of these factors to improve performance. In detail, the findings suggest to start off with communication and culture in order to foster a mutual understanding. Afterwards, work agreements and standardization within processes and communication channels should be established. Thus, considerable efforts are required within the build-up stage of shipper-TPL provider relationships. Within the execution stage, system compliance is found to enhance performance, in which formal and informal communication tools support performance improvements. Finally, this research highlights that trust develops over time by successfully working on the other factors. In addition, it has an overall positive effect on performance once a sufficient level is achieved. Research Implications: This research is the first to propose a guideline for performance improvements within offshore outsourcing of TPL services through the presented PILOOR Model. Thus, this research fills a significant gap within the body of the TPL literature. Furthermore, the PILOOR Model is believed to support practitioners in successfully building-up and executing their offshore outsourcing shipper-TPL provider relationships. Limitations &amp; Further Research: Due to the choice of methodology, this study is limited in terms of generalizability. Therefore, the authors suggest replicating this study within other offshore outsourcing shipper-TPL relationships. Ideally, the developed PILOOR Model should be tested empirically.

No description available.

No description available.