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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Development and analysis of current limiting technology for extending the life span of a power transformer.

Madiba, Tshimbalanga. 04 September 2012 (has links)
M. Tech. Electrical Engineering. / In this work, the Current Limiter Technologies lifetime of a power transformer is developed and analysed. The general overview of the different techniques of limiting fault currents in an electric power system have been analysed, with an emphasis being placed on the research regarding two types of current limiters: one based on passive magnetic, and the other on high temperature, superconducting materials.
72

Robust synchronization plan for SDH network.

Mpele, Jeremy Rodrigue. January 2010 (has links)
M. Tech. Electrical Engineering. / High-speed transmission network requires adequate synchronization planning for quality of service. Based on ITU-T synchronization network guidelines, this dissertation proposes a Synchronous Digital Hierachy (SDH) synchronization model catering for loop of synchronization and robust to communications links faults. From candidate schemes for providing synchronization information, we have adopted the master-slave strategy. Heuristics have been developed to assist in the allocation of primary and back-up reference clocks. The contribution lies in the systematic selection of master node placement, the distribution of the reference clock from master node to all slave nodes using shortest path and the allocation of system redundancy by means of clock priority table for each nodal clock. To cater for clock stability and accuracy, the use of atomic clock (Cesium, Rubidium) as frequency standard, in long term basis, has proven that clock s characteristics namely stability and accuracy may be controlled in the midst of jitter/wander. Fiber optics transmission medium has proven to be adequate for optimal clock dissemination with very trivial frequency deviation from the nominal positional instant, traceable to Primary Reference Clock.
73

Managing discipline in secondary schools in Siyabuswa, Mpumalanga province : a survey.

Mubari, David. January 2010 (has links)
Thesis (MTech. degree in Education.)--Tshwane University of Technology, 2010. / Determines how discipline is managed in public schools in Siyabuswa district. Sound legislation has been put in place by the state to address the issue of the management of discipline in schools. Despite the existence of all these structures, learners continue to behave contrary to the code of conduct.
74

Distributed joint power and rate adaption in ad hoc networks

Awuor, Frederick Mzee. January 2011 (has links)
M. Tech. Electrical Engineering. / This study proposes a distributive joint power and rate adaptation algorithm (JRPA) in ad hoc networks based on coupled interference minimisation. In the proposed method, the influence of coupled interference was controlled by dynamically adjusting network users' transmit power choices. The users are therefore aware of the current link status while determining their data rates. In addition, every maximize utility of other users as it maximizes its utility due to the inevitable cooperation, hence, improving a collective network performance. Solving this network utility maximization problem results in a supermodular game equivalence where users cooperate to maximise both local and global utility, hence the supermodular game theory concept was used to analyse the optimality and convergence of the proposed solution.
75

Security framework for low cost RFID tags.

Muwanguzi, Mark. January 2010 (has links)
Thesis (MTech. degree in Computer Systems) -- Tshwane University of Technology, 2010. / Radio Frequency Identification (RFID) systems are becoming more popular today, especially in first world countries. This is a result of the systems wide range of applications. RFID technology is used in several industries, such as: transport, sport, medicine and government institutions. The advantages that the technology offers promote its widespread use and implementation in various industries. RFID systems have the capacity to store more information than other identification technologies (for example barcode technology). Data can be read with ease as it does not require line of sight and human intervention. Despite several implementations in many industries, RFID still has some disadvantages, for instance implementation cost and issues of security and privacy. The focus of this study is the security and privacy issues in the RFID environment.
76

Leaching characteristics of copper refractory ore : effect of pre-oxidation stage.

Van der Merwe, Ryno. January 2010 (has links)
M. Tech. Metallurgical Engineering. / A novel process of leaching copper refractory ore from Nchanga mine, Zambia, in two stages consisting of a pre-oxidation step and an acid dissolution stage was investigated by means of a leach test rig.
77

The role of school governing bodies in the Mudaswali circuit, Limpopo Province.

Ndou, Dziedzi Norman. January 2009 (has links)
Thesis (MTech. degree in Education.)--Tshwane University of Technology, 2009. / School governing bodies were established in almost every school in the Limpopo Province. The establishment of school governing bodies brings democracy closer to the people. This study confines itself to the effectiveness of school governing bodies in secondary schools in the Mudaswali Circuit, Vhembe District.
78

A game theoretic power allocation scheme for multi-user multi input multi output (MIMO) system.

Njue, Danson Gitonga. January 2010 (has links)
M. Tech. Electrical Engineering. / In the recent past, there has been an increase in demand for high data rate services and system designers are always looking for ways to improve the capacity and quality of service (QoS) of wireless communication networks. The main objective of the study is to propose an asynchronous power allocation scheme based on the classical waterfilling algorithms in a multi-user MIMO uplink system. The proposed algorithm is fully distributed and eliminates the need for user synchronization during power allocation. Each user in the system competes with one another in choosing the capacity maximizing transmit power while treating the multi-user interference as noise. The problem is reduced to finding the optimal transmit covariance matrix of the users that maximizes the sum capacity of the system. We formulate the power allocation problem as a non-cooperative game and show the existence and uniqueness of the Nash Equilibrium (NE) point. The proposed Semi-Asynchronous MIMO Waterfilling algorithm maximizes the system sum capacity without the need for synchronization among users when updating their power allocation.
79

Performance of South African calcium/siliceous-based materials as sorbents for SO2 removal from Flue gas.

Ogenga, Daniel Onyango. January 2009 (has links)
Thesis (MTech. degree in Mechanical Engineering)--Tshwane University of Technology, 2009. / South Africa produces 41.3 GWe per year of which 90% is coal-derived. During combustion of coal, sulfur contained in the fuel is converted to SO2. The gas poses a serious danger for the human and environmental health. The health hazards associated with SO2 include hair loss, throat inflammation, impaired vision and respiratory illnesses. Sulfur dioxide is also forms acid rain, which leads to acidification of soils, waterways and forests. The main objective of this investigation is to explore methods of increasing lime utilization using South Africa calcium/siliceous-based sorbents for the purposes of removal of SO2 in the Flue Gas Desulfurization (FGD) system. Consequently, this study presents experimental findings on the preparation, characterization and sulfation of locally available fly ash, calcium oxide (CaO) and bottom ash. CaO was obtained from calcination of limestone in a laboratory kiln at a temperature of 900 °C and CaO/fly ash sorbent prepared using an atmospheric hydration process.
80

Improved synchronous reluctance machine with dual stator windings and capacitance injection.

Ogunjuyigbe, Ayodeji Samson Olatunji. January 2009 (has links)
D. Tech. Electrical Engineering. / Discusses the research needed to improve the performance indices (effective reactance ratio and torque index) of a synchronous reluctance machine with a simple salient rotor, using an electric circuit approach ; dual sator winding and capacitance injection, such that its power factor, torque and torque per ampere are attractive.

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