Browsing Doctoral Degrees (Electrical and Electronic Engineering) by Title
Now showing items 78-97 of 139
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Karoo Array Telescope site shielding : laboratory, computational and multi-copter studies
(Stellenbosch : Stellenbosch University, 2015-12)ENGLISH ABSTRACT: The Northern Cape in South Africa has been chosen to host the Square Kilometre Array (SKA) due to the area’s overall radio quietness. As part of the supporting systems for the Karoo Array Telescope ... -
Language modelling for code-switched automatic speech recognition in five South African languages
(Stellenbosch : Stellenbosch University, 2018-12)ENGLISH ABSTRACT: Code-switching refers to natural, spontaneous language alternation by multilingual speakers during a conversation or utterance, and is prevalent in everyday conversations by multilingual South Africans. ... -
Large-Scale clustering of acoustic segments for sub-word acoustic modelling
(Stellenbosch : Stellenbosch University, 2019-04)ENGLISH ABSTRACT: A pronunciation dictionary is one of the key building blocks in automatic speech recognition (ASR) systems. However, pronunciation dictionaries used in state-of-the-art ASR systems are hand-crafted by ... -
Lightning protection and radio frequency interference mitigation for the Karoo Array Telescope
(Stellenbosch : University of Stellenbosch, 2010-03)ENGLISH ABSTRACT: South Africa and Australia are now the two remaining countries bidding for the Square Kilometre Array (SKA), the biggest and most sensitive project ever undertaken in radio astronomy. The South African ... -
Localization and ,litigation of radio frequency interference for interferometric arrays
(Stellenbosch : Stellenbosch University, 2018-12)ENGLISH ABSTRACT: Radio telescopes have increased exponentially in sensitivity ever since the first single dish radio telescopes were built in the 1930's. This trend continues with the development of next generation ... -
Low Earth orbit satellite constellation control using atmospheric drag
(Stellenbosch : University of Stellenbosch, 1997-03)This dissertation considers the feasibility of using atmospheric drag to control constellations of micro-satellites in low Earth orbits. The constellation control requirements include an acquisition phase and a maintenance ... -
Magnetic modelling, analysis and on-chip shielding of SFQ Circuits
(Stellenbosch : Stellenbosch University, 2018-03)ENGLISH ABSTRACT: Single Flux Quantum (SFQ) based electronic circuits are susceptible to failure if exposed to external magnetic fields, even in very small quantities. Operating margins of SFQ circuits have shown to decrease ... -
The measurement of radio frequency complex permeability of thin round wires
(Stellenbosch : Stellenbosch University, 2003-04)ENGLISH ABSTRACT: This thesis is concerned with the measurement of the complex permeability of thin round wires at radio frequencies. This is of interest as such wires are used in various applications, such as absorbing ... -
Measuring, refining and calibrating speaker and language information extracted from speech
(Stellenbosch : University of Stellenbosch, 2010-12)ENGLISH ABSTRACT: We propose a new methodology, based on proper scoring rules, for the evaluation of the goodness of pattern recognizers with probabilistic outputs. The recognizers of interest take an input, known to ... -
The method of manufactured solutions for the verification of computational electromagnetic codes
(Stellenbosch : Stellenbosch University, 2013-03)ENGLISH ABSTRACT: In this work the Method of Manufactured Solutions (MMS) is introduced for the code veri cation of full-wave frequency dependent electromagnetic computational software. At rst the method is sketched ... -
Methods to quantify and reduce rotor losses in a solid rotor yoke permanent magnet machine
(Stellenbosch : University of Stellenbosch, 2010-03)ENGLISH ABSTRACT: Certain types of electric machines are particularly susceptible to the proliferation of eddy currents flowing within the solid conducting regions in the rotor. Single-layer, non-overlapping windings ... -
Microwave dielectric heating through interference modulation with narrow band high power sources
(Stellenbosch : Stellenbosch University, 2002-12)ENGLISH ABSTRACT: One of the most difficult problems in microwave dielectric heating is the generation and control of field and heating patterns. A technique allowing the synthesis of different, pre-determinable heating ... -
Miniaturised multilayer RF and microwave Circuits
(Stellenbosch : Stellenbosch University, 2016-03)ENGLISH ABSTRACT: Ceramic and laminate multilayered technologies are explored in the design of novel circuit topologies and in novel implementations of classical circuit topologies. A cross-slot coupled filter topology ... -
Modal-based design techniques for circular quadruple-ridged flared horn antennas
(Stellenbosch : Stellenbosch University, 2015-03)ENGLISH ABSTRACT: This dissertation presents modal-based techniques for the effective systematic design of quadruple-ridged flared horns (QRFHs) as reflector feeds for radio astronomy applications. A new excitation ... -
Modelling and mitigation of specular multipath interference in a dual-frequency phase comparison FMCW radar system
(Stellenbosch : Stellenbosch University, 2017-03)ENGLISH ABSTRACT: Digital signal processing technology has improved greatly over the last two decades. Increased processing power, cheaper memory and higher sampling rates have enabled the application of Frequency-Modulated ... -
Modelling of Antenna Responses
(Stellenbosch : Stellenbosch University, 2016-12)ENGLISH ABSTRACT: This dissertation presents surrogate modelling techniques for the radiation patterns and scattering parameters of antennas. The models are developed in the context of calibration of re ector antennas ... -
Modelling, estimation and compensation of imbalances in quadrature transceivers
(Stellenbosch : University of Stellenbosch, 2011-03)ENGLISH ABSTRACT: The use of the quadrature mixing topology has been severely limited in the past due to its sensitivity towards mismatches between its signal paths. In recent years, researchers have suggested that digital ... -
Multi-bias decomposition-based optimisation for the extraction of small-signal GaAs FET models
(Stellenbosch : Stellenbosch University, 1999-07)ENGLISH ABSTRACT: The availability of accurate nonlinear models is essential for the accurate and cost effective design of high frequency telecommunication systems. A key step in the creation of such models is the ... -
Multi-mode antennas for hemispherical field-of-view coverage
(Stellenbosch : Stellenbosch University, 2015-03)ENGLISH ABSTRACT: This dissertation proposes a multi-mode antenna element excited through a multiconductor feed. It is shown that each of the orthogonal transverse electromagnetic modes supported by the antenna feed ... -
Natural balancing mechanisms in converters
(Stellenbosch : University of Stellenbosch, 2011-03)AFRIKAANSE OPSOMMING: Hierdie proefskrif handel oor die natuurlike balanserings meganismes van veelvlakkige en modulêre omsetters wat fase-skuif dragolf puls wydte modulasie gebruik. Die meganismes kan in twee hoof groepe ...
