Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"numerical optimisation"”.
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Numerical optimisation of biomedical implant characteristics for increased service life.
This study focused on the development of a numerical optimisation technique with the aim to decrease implant stress shielding which in turn could increase Total Hip Arthroplasty (THA) service life and reduce patient discomfort by employing a distributed stiffness along implant length. Research …
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Numerical optimisation and theoretical analysis of complex microchannel heat exchangers
… fluid flow. Microchannel heat sinks used were numerically modelled from highly conductive (aluminium) solid material substrate. ANSYS FLUENT Response Surface Optimisation Tool (RSO) was used to numerically optimise and compare the performance of combined microchannel heat sinks with perforated, …
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Numerical optimisation methods for power consumption in multi-hop mobile phone networks
… is nonconvex, therefore we have a non convex optimisation problem. Since the problem is non convex, the obtained solutions are only local minimisers. We present and prove two theorems which, in general terms, state that at a local minimiser, the capacity over the links is fully exploited. We …
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Reduced order modelling and numerical optimisation approach to reliability analysis of microsystems and power modules
… aim of this PhD program is the development of an optimisation and risk based methodology for reliability and robustness predictions of packaged electronic components. Reliability based design optimisation involves the integration of reduced order modelling, risk analysis and optimisation. The …
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Geometric and numerical optimisation of single- and two-phase convective heat transfer in microchannel heat sinks
… of its high thermal conductivity. Simulation and optimisation studies of two-phase and single-phase convective heat transfer in microchannels are limited considering the way they have been done presently. Goal driven optimisation was used and the volumes of microchannels and heat sinks were fixed …
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The use of numerical optimisation techniques in computational fire engineering models: a study through evacuation modelling analyses
… needs to be addressed. In the other hand, numerical optimisation techniques have been applied to a range of different fields such as structural analysis. These techniques have shown to be a powerful tool for designers, saving their time and consequently reducing costs during the process. …
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Optimisation modelling for microelectronics packaging and product design
… with integrated finite element routines, with numerical optimisation and statistical methods. This integrated approach is intended as a modelling tool for calculating optimal design solutions for electronic packaging and component assembly with a focus on die reliability and the thermal …
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Numerical modelling of advanced modulation formats and WDM transmission
… systems. The first part of this work focuses on numerical optimisation of dense wavelength division multiplexing (DWDM) system design. We employ advanced spectral domain filtering techniques and carrier pulse reshaping. We then apply these optimisation methods to investigate spectral and temporal …
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Mathematical and Computational Methods for the n-Body Problem
… that combines variational analysis, advanced numerical optimisation, and rigorous computer-assisted proofs (CAPs) to detect, classify, and validate periodic solutions of the n-body problem. The work begins by reformulating the search for periodic trajectories as a variational problem, where …
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Improving Results of Differential Evolution Algorithm
Optimisation problems are of prime importance in scientific and engineering communities. Many day-to-day tasks in these fields can be classified as optimisation problems. Due to their enormous solution spaces, optimisation problems frequently lie in class NP. In such cases, engineers and …
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Detecting, locating and sizing leaks in gas-filled pipes using acoustical measurements
… this thesis, an alternative approach which uses optimisation methodology to detect, locate and size multiple leaks in a duct is described. The optimisation algorithms are applied to a measurement of the duct’s input impedance but they are able to cope with the presence of multiple leaks. Results …
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AI-based hybrid optimisation of multi-megawatt scale permanent magnet synchronous generators for offshore wind energy capture
… selection, detailed design, sizing and optimisation of a 10.8 MW permanent magnet radial flux synchronous generator (RF-PMSG) to be used in the next generation of offshore wind farms. From an analytical viewpoint, the results suggested the use of a medium speed RF-PMSG utilizing a …
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Simulation Optiisation and Markov Models for Dynamic Ambulance Redeployment
… Markov model by considering two ambulances. Numerical experiments are used to gain insights into optimal move- up policies based on the three models. In the second part of the investigation, we present three move-up models for realistic-sized problems. The first two of these models extend …
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Geometric modelling and shape optimisation of pharmaceutical tablets. Geometric modelling and shape optimisation of pharmaceutical tablets using partial differential equations.
… tablet in various shapes have been es-timated numerically. This work also presents an extended formulation of the PDE method to a higher dimensional space by increasing the number of pa-rameters responsible for describing the surface in order to generate a solid tab-let. The shape and size of …
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On the synthesis of optimum monopulse antenna array distributions
… optimal solutions, along with constrained numerical optimisation. The thesis is based on original research done by the author, except where explicit reference is made to the work of others.
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Modeling population dynamics of rhino-poacher interaction across South Africa and the Kruger National Park using ordinary differential equations
… values are obtained. The remaining unknowns are numerically optimised based on the fixed value parameters. This is considered a constrained system, and the results obtained can only be viewed as constrained predictions based on parameter values obtained by a combination of trial and error and …
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Optimisation of Phase-Only Computer-Generated Holograms
… Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) optimisation algorithm together with the Sequential Slicing (SS) technique offers an efficient approach for 3D phase-only CGH by evaluating individual depth slices iteratively as opposed to evaluating the entire volume. The Multi-Frame Holograms …
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A novel optimised design using slots for flow control and high-lift performance of UCAVs
… the chordwise slot are identified for the numerical optimisation. They are: location, width, length and angle of trajectory of chordwise cavity relative to freestream. The angle of trajectory of chordwise slot is measured with respect to the trailing edge of the air vehicle. The results of …
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Experimental and theoretical characterisation of tunable fibre gratings
… apodisation techniques, experimental results and numerical optimisation of the shading functions and all the practical parameters involved in the fabrication are detailed. The measurement of chromatic dispersion in fibres and FBGs is detailed and an estimation of its accuracy is given. An overview …
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Wavelet-like filter banks for multi-dimensional and multi-resolution signal processing
… the implementation of the wavelet transform by numerical optimisation of various constraints associated with the wavelet basis function, thereby enabling various multi-dimensional and multi-resolution signal processing operations to be performed efficiently. Many efforts, including theoretical …
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