ETD Collection

Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/104


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    The inability of peacekeeping to address Rwandan Congolese security dilemma
    (University of the Witwatersrand, Johannesburg, 2023) Kabwe, Divine
    Rwanda’s involvement in the DRC is more intricate than that of the other actors. The Rwandan army has been battling the Democratic Forces for the Liberation of Rwanda (FDLR), a political-military movement which is active in the North and South Kivu provinces of the DRC. The presence of the FDLR in those provinces is problematic as it gives Rwanda a reason to continuously intervene in the DRC. . The reality is that historical issues will take a long time to resolve and that the peacebuilding process in the DRC cannot be tied to a timeline. The failings of the UN via MONUC and its successor MONUSCO have only served to reinforce this scepticism and sense of self-reliance in Kigali. Another consideration to add here is that Rwanda has become one of the top 10 providers of troops to UN peacekeeping missions, primarily operating in Darfur. Censuring Rwanda for its involvement in DR Congo could put this at risk, making UN and donor engagement with Rwanda politically more complex than just a case of whether to cut or maintain aid. The current interest by regional and international actors in the crisis provides an opportunity for laying a framework for the resolution of the underlying structural issues that have plagued the DRC for a long time.
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    JSE-listed firms and M&A’s: where is the economic value?
    (University of the Witwatersrand, Johannesburg, 2020) Taylor, Amir; Page, Daniel
    This research empirically assesses the stock price reactions to mergers and acquisitions announcements by JSE-listed target and acquirer firms. The following is assessed over the defined windows: the target and acquirer firms, the method of funding (cash or stock) for both target and acquirer firms and lastly industry mergers with target and acquirer firms grouped together and separately. Data is collected for 87 merger deals, consisting of 87 target and acquirer firms. The period assessed is from 1990 to 2019. The event study methodology and hence the market model are employed as the primary methodology, with the net-market-returnmodel employed as a robustness check. T-tests, paired t-tests and a one-way ANOVA model are employed to test for relative significance. The results in this study are unique and contribute to how the South African market views M&A announcements. Hence this will influence the contemporary understanding of the South African economy towards M&A’s.
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    The Positioning of electromagnetic near field hotspots within a resonant cavity for applications in microwave thermal ablation
    (2022) Young, Graeme Robin; Clark, Alan; Rubin, David
    The investigation into moving electromagnetic near field hotspots inside a resonant cavity is presented. The investigation is focused on providing an alternative approach to thermal ablation of tumours, by inducing a hotspot over a tumour instead of using an interstitial antenna. The methodology comprised comparing various electromagnetic solvers, verifying the simulation techniques, characterising the resonance within a rectangular resonant cavity, and attempting to control the movement of its hotspots by introducing a phase shift between its sources and modifying their frequency. The effects of dielectric media of the field were also investigated. It was determined that incremental frequency shifts only progressively moved the system’s hotspots between 2.6 and 2.7 GHz and phase shifting only worked between 2.55 and 2.7 GHz when the feeds were on opposite walls. At the system’s eigenfrequencies, no pattern change was evident, indicating that when the chamber was resonating, the field pattern was set. Further, it was determined that the bandwidth of the characteristic modes of the system were very narrow, such that the addition of dielectric material completely altered the resonance of the system and the eigenfrequencies shifted. Therefore, the application of this method to thermal ablation, which requires high precision, accuracy and control, was deemed impractical. Future recommendations include using adjustable cavity geometry and directive microwave sources to design for specific field patterns. Additionally, it is recommended to investigate the validity of the ‘reverse problem’ to create a specific current distribution around the resonant cavity. This is reminiscent of the three-dimensional Green’s Theorem, which would induce the desired hotspot pattern from the surrounding current distribution.