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A novel continuously variable transmission has previously been designed that is capable of addressing a number of concerns within the automotive industry such as reduced emissions. At the commencement of this research, the design was in the early stages of development and little attempt had been previously made to optimise the design to meet specific measurable targets. This thesis utilises and modifies several design approaches to take the design from the concept stage to a usable product. Several optimisation techniques are adapted and created to analyse the CVT from both a design and tribological prospective. A specially designed optimisation algorithm has been created that is capable of quickly improving each critical component dimension in parallel to fulfil multiple objectives. This algorithm can be easily adapted for alternative applications and objectives. The validity of the optimised design is demonstrated through a simulation-tool that has been created in order to model the behaviour of the CVT in a real automotive environment using multiple fundamental theories and models including tire friction and traction behaviour. This powerful simulation tool is capable of predicting transmission and vehicular behaviour, and demonstrates a very good correlation with real-world data. A design critique is then performed that assesses the current state of the CVT design, and looks to address some of the concerns that have been found through the various methods used. A specific prototype design is also presented, based on the optimisation techniques developed, although the actual creation of a prototype is not presented here. Additional complementary research looks at the accuracy of the tire friction models through the use of a specially design tire friction test rig. Furthermore, a monitoring system is proposed for this particular CVT design (and similar) that is capable of continuously checking the contact film thickness between adjacent elements to ensure that there is sufficient lubricant to avoid metal-on-metal contact. The system, which is based around capacitance, requires the knowledge of the behaviour of the lubricant’s permittivity at increased pressure. This behaviour is studied through the use of a specially-designed experimental test rig.

The overarching objective of this thesis was to develop tools for parallelising, optimising, and implementing algorithms on parallel architectures, in particular General Purpose Graphics Processors (GPGPUs). Two projects were chosen from different application areas in which GPGPUs are used: a defence application involving image compression, and a modelling application in bioinformatics (computational immunology). Each project had its own specific objectives, as well as supporting the overall research goal. The defence / image compression project was carried out in collaboration with the Jet Propulsion Laboratories. The specific questions were: to what extent an algorithm designed for bit-serial for the lossless compression of hyperspectral images on-board unmanned vehicles (UAVs) in hardware could be parallelised, whether GPGPUs could be used to implement that algorithm, and whether a software implementation with or without GPGPU acceleration could match the throughput of a dedicated hardware (FPGA) implementation. The dependencies within the algorithm were analysed, and the algorithm parallelised. The algorithm was implemented in software for GPGPU, and optimised. During the optimisation process, profiling revealed less than optimal device utilisation, but no further optimisations resulted in an improvement in speed. The design had hit a local-maximum of performance. Analysis of the arithmetic intensity and data-flow exposed flaws in the standard optimisation metric of kernel occupancy used for GPU optimisation. Redesigning the implementation with revised criteria (fused kernels, lower occupancy, and greater data locality) led to a new implementation with 10x higher throughput. GPGPUs were shown to be viable for on-board implementation of the CCSDS lossless hyperspectral image compression algorithm, exceeding the performance of the hardware reference implementation, and providing sufficient throughput for the next generation of image sensor as well. The second project was carried out in collaboration with biologists at the University of Arizona and involved modelling a complex biological system – VDJ recombination involved in the formation of T-cell receptors (TCRs). Generation of immune receptors (T cell receptor and antibodies) by VDJ recombination is an enormously complex process, which can theoretically synthesize greater than 1018 variants. Originally thought to be a random process, the underlying mechanisms clearly have a non-random nature that preferentially creates a small subset of immune receptors in many individuals. Understanding this bias is a longstanding problem in the field of immunology. Modelling the process of VDJ recombination to determine the number of ways each immune receptor can be synthesized, previously thought to be untenable, is a key first step in determining how this special population is made. The computational tools developed in this thesis have allowed immunologists for the first time to comprehensively test and invalidate a longstanding theory (convergent recombination) for how this special population is created, while generating the data needed to develop novel hypothesis.

A number of mathematical models are used nowadays to describe behaviour of the reallife water distribution system (WDS). It is a well known fact that, to have any meaningful use, any WDS mathematical model must be calibrated first. Here, calibration is defined as process in which a number of WDS model parameters are adjusted until the model mimics behaviour of the real WDS as closely as possible. In this thesis, WDS mathematical models that are used to model water quantity aspect only are analysed. Three hydraulic models considered here are: (1) steady-state flow model, (2) quasi-steady flow (extended period simulation) model and (3) unsteady flow model. The calibration problem analysed here is formulated as a constrained optimisation problem of weighted least square type with the objective defined in a way that enables effective incorporation of prior information on calibration parameters. WDS calibration problem is then analysed in detail, including special issues of identifiability, uniqueness and stability of the problem solution. A list of diagnostic and other statistics and analysis is presented to improve existing calibration approaches by providing partial insight into the calibration process. Calibration of WDS hydraulic models is further improved by the development of new hybrid optimisation method. Being closely related to calibration, the problem of sampling design for calibration of WDS hydraulic models is also addressed here. First, sampling design is formulated as a constrained two-objective optimisation problem. Then, two novel models are developed to solve it. The first model is based on standard, single-objective Genetic Algorithms (SOGA). The second model is based on multi-objective Genetic Algorithms (MOGA). Finally, all novel methodologies presented here are verified successfully on multiple case studies that involve both artificial and real-life WDS. At the end, relevant conclusions are drawn and suggestions for further research work are made.

Research on interventions aimed to promote energy savings has shown support for direct feedback using in-home displays (IHDs) to reduce energy consumption. These displays are electronic devices that provide real-time energy information and are emerging as an effective tool to communicate with people about their energy consumption. How feedback is presented to people and how they understand the meaning of such feedback largely depends on the design of the display, yet there are relatively few studies that investigate the way in which the display can best be designed to present energy information and motivate energy-saving behaviour. Further, even though there is a wide range of variations in the visual presentation of feedback, there is a lack of focus on the process of optimising the IHD design. This thesis aims to address the need for designing IHDs at the display component level, by examining three types of display design (numerical displays, analogue displays using speedometer dials, and ambient displays using emotional faces) in both laboratory-based computer-simulated experiments and field-based experiments: participants’ abilities to detect changes in energy information shown on the computer-simulated displays were measured by means of accuracy rate and response time, and their subjective preferences for display types were assessed against experimental data; live energy data were displayed using the three design types in a student residence at the University of Bath to see how they would influence energy-use behaviour. Results from the laboratory experiments demonstrated that both accuracy rate and response time for seeing changes in the information displayed were strongly associated with the type of display design. Participants preferred numerical display and were better at detecting changes in information with this display than with the other two. Conversely, the student residence experiments showed that when participants’ attention was divided in a household setting, there was no difference in energy consumption among experimental groups who received information from any of the three display types. However, these experimental groups used significantly less energy compared with control groups, who had no displays installed. It was concluded that 1) the mere presence of a display device could influence people’s behaviour, regardless of the type of display design, people’s preferences or the level of user engagement with the display, although there was a strong indication that the ambient design worked better than the other two designs at an arbitrary statistical significance level of 0.95, and 2) subjective preferences and computer-simulated studies are poor guides to the actual performance of IHDs in real-world settings. This work helps establish how IHDs can be designed and the influence that they may have on people’s energy-consumption behaviour. It also contributes to the literature of exploring people’s perceptibility of energy information. The method used is replicable and can be applied in similar studies on energy display design. Lastly, the improved understanding gained through this work will facilitate the development of effective smart meter display technology that may help people adopt conscious energy behaviour in the long term.

The design processes for solar photovoltaic (PV) systems is improved to achieve higher reliability and reduced levelised cost of energy (LCOE) throughout this thesis. The design processes currently used in the development of PV systems are reviewed. This review process included embedding the author in a project to deliver four rooftop PV systems which totalled a megawatt of installed generating capacity, which at the time represented very significant system sizes. The processes used in this are analysed to identify improvement potential. Shortcomings are identified in three main areas: safety assurance, design process integration and financial optimisation. Better design process integration is required because data is not readily exchanged between the industry standard software tools. There is also a lack of clarity about how to optimise design decisions with respect to factors such as shading and cable size. Financial optimisation is identified as a challenge because current software tools facilitate optimising for maximum output or minimum cost, but do not readily optimise for minimum levelised cost of energy which is the primary objective in striving for grid parity. To achieve improved design process integration and financial optimisation, a new modelling framework with the working title SolaSIM is conceived to accurately model the performance of solar photovoltaic systems. This framework is developed for grid connected systems operating in the UK climate, but it could readily be adapted for other climates with appropriate weather data. This software development was conducted using an overarching systems engineering approach from design and architecture through to verification and validation. Within this SolaSIM framework, the impact of shading on array and inverter efficiency is identified as a significant area of uncertainty. A novel method for the calculation of shaded irradiance on each cell of an array with high computational efficiency is presented. The shading sub-model is validated against outdoor measurements with a modelling accuracy within one percent. Final verification of the over-arching SolaSIM framework found that it satisfied the requirements which were identified and actioned. The author installed the new CREST outdoor measurement system version 4 (COMS4). COMS4 is a calibrated system which measures 26 PV devices simultaneously. Validation of SolaSIM models against COMS4 found the modelling error to be within the 4% accuracy target except two sub-systems which had electronic faults. The model is validated against PV systems and found to be within the specified limits.

yes / The problem of parametric surface meshing for the purpose of design optimisation using finite element analysis is considered. Here the surface mesh is generated as a solution of a suitably posed boundary value problem implemented on a 2D parameter space. A robust meshing scheme is presented where an initial mesh is manipulated, with the aid of the 2D parameter space, so as to obtain a suitable surface triangulation. This meshing scheme can then be used to create suitable finite element meshes with which accurate design optimisations can be carried out.

<p> An oblique four bar structural model with fixed member ends, being the most general building for space frames, is analysed under free and steady-state vibrations, using discrete mass method. </p> <p> Experimental techniques for measurement of free and steadystate vibrations are described. </p> <p> Experimental results have been compared against analytical ones. </p> / Thesis / Master of Engineering (MEngr)

<p> An oblique four bar structural model with fixed member ends, being the most general building block for space frames, is analysed for establishing its influence coefficients, using the Finite Element Matrix Method. </p> <p> Experimental techniques for measurement of the flexibility influence coefficients of the model are described. </p> <p> Experimental results have been compared against analytical ones. </p> / Thesis / Master of Engineering (MEngr)