4. Electronic Theses and Dissertations (ETDs) - Faculties submissions

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Critiquing TikTok as a stage: Investigating Confessional Performance on TikTok and its capacity to cultivate feelings of intimacy and communitas within a community of young adult users
(University of the Witwatersrand, Johannesburg, 2024) Buckland, Sarah; DaCosta, Neka
The presence of loneliness, exacerbated by the Covid-19 pandemic, is a persistent issue facing young adults in South Africa and abroad. Social media platforms, specifically TikTok, afford a sense of social interaction for those socially and geographically separated. One avenue for this interaction is through the production of increasingly confessional content on the social media platform. In this paper, I identify this presence of confessional content on TikTok and trace its roots to Confessional Performance traditions. I then interrogate the potential of Confessional Performance on TikTok to establish intimacy and elements of communitas. Irem Sot’s article entitled Fostering Intimacy on TikTok: A platform that listens and creates a safe space (2022) provides beneficial insight into the role TikTok’s algorithm has in establishing a sense of intimacy and community amongst its dedicated users and is used as a vital point of reference throughout the paper. Through the addition of an autoethnographic creative research approach, supported by thorough desktop research, I can outline the initiation of intimacy and community on TikTok, which begins with a moment of confession and continues when a second party validates this moment. Furthermore, I create and analyse my confessional TikTok series, ‘I want to talk to you, I want you to talk to me’, paying close attention to audience interaction experienced during this series as a means to a) reflect on the interpretation of intimacy and communitas through the lens of both a TikTok creator and viewer and b) determine the capacity of this kind of confessional performance on Tik Tok to successfully (or unsuccessfully) cultivate intimacy and communitas.
Exploring Immersive Technology in Flight Training: Trainee Pilots’ Perceptions of Learning and Behavioural Outcomes
(University of the Witwatersrand, Johannesburg, 2024) Naidoo, Sarita; Naidoo, Preven
The primary aim of this research was to examine the effectiveness of immersive technology on trainee pilots’ learning and behavioural outcomes. The first phase of the research included building a survey to measure trainees’ learning and behavioural outcomes. An initial sample of fifteen subject-matter experts assisted in creating the final survey. The second phase of the research involved distributing the survey to trainee pilots and consisted of twenty-seven participants. Spearman’s Rank Correlation and Kendall’s tau-b Correlation were run on the data. A Regularized Exploratory Factor Analysis (REFA) method was used to ensure the constructed survey measured trainee pilots’ perceptions of their learning and behavioural outcomes. The main results showed a significant relationship between the use of immersive flight simulation training and trainee pilots’ learning and behavioural outcomes. On the other hand, age, level of experience as a pilot, total flying time, and total flying time in modern flight decks had no significant association with trainee pilots’ perceptions of their learning and behavioural outcomes. The small sample size affected the findings of the research and should be considered a limitation of the study. The findings of the research have implications for the design of flight simulations.
Self-Representations of Cultural Identity in South African Indian Filmmaking, 2004 – 2017
(University of the Witwatersrand, Johannesburg, 2024) Prem, Temara; Ebrahim, Haseenah
In a post-apartheid context, the filmmaking practices of South African Indian diasporic communities serves as a fertile ground for examining complexities of cinematic representation of identity negotiations and cultural expression. This research interrogates the extent to which cinematic self-representation in three South African Indian films—Broken Promises (2004), For Better For Worse (2010), and Keeping Up with the Kandasamys (2017)—enables a visibility of complex heterogenous representations of cultural identity. Employing a combination of contextual and textual analysis, the study conducts a detailed critical analysis inspecting how these films navigate between cultural homogenisation and heterogeneous identity constructions and representations. The research finds that cultural specificity is exhibited in the films to limited degrees while more monolithic representations do serve to unify South African Indian experiences while also extending accessibility to external audiences. The extent to which these films manage to create visibility of the complex identities is intricately tied to varying modes of production and distribution, revealing both the opportunities and constraints in the ongoing project of cinematic self-representation for South African Indian communities. This study contributes to the underexamined field of South African Indian film scholarship, as well as broader discourses of postcolonial filmmaking by re- interpreting Bhabha's concept of the 'third space' (1994) as complicated by the specificities of 'place'. Emerging from the findings, an analytic framework of ‘Prismatic Analysis’ is conceptualised and proposed as a focused framework within postcolonial film studies that captures the complex and hybrid nature of postcolonial diasporic communities.
Machine Learning applied to Computational Creativity: The use of AI in Authoring Film Screenplays
(University of the Witwatersrand, Johannesburg, 2024) Serapelo, Thuto; Whitcher, Raymond
Artificial Intelligence, from the inception of the field in the 1950s, supported the notion of having computer software or programs that are capable of exhibiting creativity or applications that can execute tasks that are deemed to be creative. This research addresses the question: To what extent can Artificial Intelligence exhibit creativity in authoring film screenplays, as evaluated through a comparative analysis using the 90-point screenplay guideline? - This study delves into the nuances of film structure, plot, dialogue, character, emotion and narratology. The results revealed that although Artificial Intelligence is on par with human creativity when analysing some aspects of narratives/screenplays. It still lags in the other elements examined, and where AI produced superior work is when it worked in collaboration with a human screenwriter and did far worse when working entirely alone and unaided. This research offers insights into the broader implications of AI in the creative arts, indicating a promising yet complex future.
Counting Reward Automata: Exploiting Structure in Reward Functions Expressible in Decidable Formal Languages
(University of the Witwatersrand, Johannesburg, 2024-07) Bester, Tristan; Rosman, Benjamin; James, Steven; Tasse, Geraud Nangue
In general, reinforcement learning agents are restricted from directly accessing the environment model. This restricts the agent’s access to the environmental dynamics and reward models, which are only accessible through repeated environmental interactions. As reinforcement learning is well suited for use in complex environments, which are challenging to model, the general assumption that the transition probabilities associated with the environment are unknown is justified. However, as agents cannot discern rewards directly from the environment, reward functions must be designed and implemented for both simulated and real-world environments. As a result, the assumption that the reward model must remain hidden from the agent is unnecessary and detrimental to learning. Previously, methods have been developed that utilise the structure of the reward function to enable more sample-efficient learning. These methods employ a finite state machine variant to facilitate reward specification in a manner that exposes the internal structure of the reward function. This approach is particularly effective when solving long-horizon tasks as it enables the use of counterfactual reasoning with off-policy learning which significantly improves sample efficiency. However, as these approaches are dependent on finite-state machines, they are only able to express a small number of reward functions. This severely limits the applicability of these approaches as they cannot model simple tasks such as “fetch a coffee for each person in the office” which involves counting – one of the numerous properties finite state machines cannot model. This work addresses the limited expressiveness of current state machine-based approaches to reward modelling. Specifically, we introduce a novel approach compatible with any reward function which can be expressed as a well-defined algorithm We present the counting reward automaton – an abstract machine capable of modelling reward functions expressible in any decidable formal language. Unlike previous approaches to state machine-based reward modelling, which are limited to the expression of tasks as regular languages, our framework allows for tasks described by decidable formal languages. It follows that our framework is an extremely general approach to reward modelling – compatible with any task specification expressible as a well-defined algorithm. This is a significant contribution as it greatly extends the class of problems which can benefit from the improved learning techniques facilitated by state machine-based reward modelling. We prove that an agent equipped with such an abstract machine is able to solve an extended set of tasks. We show that this increase in expressive power does not come at the cost of increased automaton complexity. This is followed by the introduction of several learning algorithms designed to increase sample efficiency through the exploitation of automaton structure. These algorithms are based on counterfactual reasoning with off-policy RL and use techniques from the fields of HRL and reward shaping. Finally, we evaluate our approach in several domains requiring long-horizon plans. Empirical results demonstrate that our method outperforms competing approaches in terms of automaton complexity, sample efficiency, and task completion.
Improving grade estimation using machine learning: a comparative study of ordinary kriging against machine learning algorithms
(University of the Witwatersrand, Johannesburg, 2024) Akpabio, Aniekan
This study investigated the efficiency of machine learning (ML) methods in the accurate prediction of ore grades, placing them in direct comparison with the established Ordinary Kriging (OK) methodology, a mainstay in geostatistical analysis. Utilising a dataset from a complex platinum group elements (PGE) deposit, the research assessed a suite of ML algorithms—namely, Random Forest (RF), Decision Trees (DT), Support Vector Regression (SVR), and particularly 𝑘- Nearest Neighbours (𝑘NN). The latter is highlighted for its adeptness in assimilating spatial data correlations intrinsically, echoing the insights from Nwalia's analytical explorations. The research engages with detailed swath plot analyses, comparative metric evaluations, and a nuanced understanding of spatial continuity, to illustrate the distinct advantages and operational competencies of the models. 𝑘NN, with its reliance on local data proximities and non-parametric nature, alongside RF, with its ensemble-based approach, emerged as capable in point estimate predictions. These models adeptly delineated local grade variations, demonstrating a high degree of reliability to the observed data and outperforming the OK model in both precision and accuracy. Further, the study examined block estimate predictions, a cornerstone in practical mining and resource estimation, where both 𝑘NN and RF demonstrated a commendable ability to generalise predictions over larger spatial extents. This translates into significant potential for enhancing mineral resource estimation processes, tailoring them to the granular specifics of a given ore body, and refining block model accuracy to inform more strategic mining operations. While the results endorse the ML methodologies as robust alternatives to traditional geostatistical techniques, the research also highlights the nuanced nature of these predictions. Factors such as the ore body's heterogeneity, the appropriateness of the variogram model, and the interplay between prediction scale and algorithmic performance are examined, offering a critical lens through which the suitability of each method is assessed. iv The research suggests that while some models like LR and SVR are bounded by linear assumptions and hyperparameter sensitivities, non-linear models such as DT and RF can innately navigate the complex, multifaceted layers of geological data. The comprehensive evaluation extends to propose a novel set of performance metrics designed to capture the intricacies of grade prediction, thereby aligning closely with the operational demands and decision-making processes in the mining industry.
The improvement of the on-time delivery for “company x” e-commerce orders during the golden quarter
(University of the Witwatersrand, Johannesburg, 2024) Sukazi, Thobile Nomalungelo; Sunjka, Bernadette
E-commerce has revolutionized global business and consumer interactions, offering convenience and accessibility across various domains like Business-to-Business (B2B), Business-to-Consumer (B2C), and Consumer-to-Consumer (C2C). The COVID-19 pandemic has accelerated digital transformation, with South Africa's e-commerce market showing robust growth projections, fuelled by factors such as improved internet penetration and shifting consumer behaviours. The Omni-channel strategy has become standard, with leading players leveraging digital capabilities to maintain market share. Notably, the "Golden Quarter" of retail, encompassing events like Black Friday and Singles Day, presents a pivotal opportunity for retailers to boost profits through strategic promotional efforts. As the market matures, focus shifts to optimizing the final mile of delivery, aiming to improve efficiency and reduce costs. This project seeks to explore tailored strategies for final mile optimization in Company X, aligning with the broader goal of enhancing efficiency and customer experiences in South Africa's growing e-commerce sector. Despite being the second-largest wholesale food distributor in South Africa, Company X experienced significant on-time delivery performance declines, particularly in its discount retailer brand, Banner 3. The analysis identified logistical bottlenecks in the final mile as the primary contributor to these challenges, resulting in an average delay of 4.3 days in the order fulfilment process. Additionally, the study highlighted the importance of addressing these challenges to maintain customer satisfaction, loyalty, and competitiveness in the rapidly evolving South African e-commerce landscape. This study employs a comprehensive framework and systematic approach to investigate the research questions and objectives. A qualitative research design involves one-on-one interviews conducted digitally via Microsoft Teams. Ethics clearance (MIAEC 099/23) was obtained, ensuring transparency and participant understanding. The sampling strategy prioritizes quality over quantity, with six diverse participants selected to provide rich qualitative data. Data analysis follows Braun and Clarke's thematic analysis approach, incorporating triangulation methods and emphasizing thorough documentation to ensure validity and reliability. This research has thoroughly investigated Company X's final mile delivery challenges during the Golden Quarter, providing comprehensive insights and recommendations for enhancement. Key findings underscore the significance of accurate forecasts, planning collaboration, proximity to customers, fleet and technology utilization, customer service levels, and delivery types in optimizing delivery performance. Recommendations encompass advanced forecasting models, collaborative planning efforts, tailored customer promises, technological enhancements, and automation to address identified challenges and capitalize on opportunities for improvement. The proposed strategies offer a strategic roadmap for Company X to enhance efficiency, customer satisfaction, and competitiveness in the e-commerce landscape, aligning with the study's objectives and concluding the project successfully. The tailored recommendations contribute valuable strategies for improving efficiency, customer satisfaction, and competitiveness. Future research could focus on evaluating the implementation of these strategies and exploring emerging technologies to further optimize the delivery process and adapt to evolving market dynamics.
The Effects of Rectilinear Acceleration and Deceleration on Shock Formation near a Stationary Boundary
(University of the Witwatersrand, Johannesburg, 2024) Morrow, Sean Robert
Inspired by the world land speed record vehicles the Thrust and Bloodhound supersonic cars (SSC), the focus of this dissertation is to investigate how rapid acceleration affects the formation of shock waves coming off an object travelling in ground effect. Due to the proximity of the ground, these shock waves are not able to freely propagate under the object and must interact with, and reflect off, the ground. Steady state and transient models of aerofoils, accelerating from Mach 0.05 to Mach 2.00 at a test run acceleration of 3 g and an extreme acceleration of 176 g are developed and compared to reveal that the transient shock wave development trails that of the constant velocity aerofoil. The main reason for this difference is that the transient flow is unable to fully develop and reach a state of equilibrium. The extreme acceleration allowed even less time for the flow to develop, and the difference in the shock location continuously increased throughout the acceleration. The same difference in shock location was evident when these models were decelerated back down to Mach 0.05. However, the extreme deceleration and increasing difference in shock location drastically changed the transonic and subsonic flow field, especially as flow features and shock waves from the higher velocity flow overtook the model. In each acceleration and deceleration case, the transient flow history effects subsided and the aerodynamic performance from the transient analysis converged with the aerodynamic performance from the steady state analysis. Under acceleration the transient performance converged at a higher steady state Mach number, while under deceleration the transient performance converged at a lower steady state Mach number. As the magnitude of the acceleration and deceleration increased the Mach number at which the results converged shifted to higher and lower Mach numbers respectively. Models with different orientations and ground clearances were also compared against each other and a case at free flight to determine the impact ground effect has on the formations and locations of the shock waves. Increasing ground effect was shown to promote the formation of shock waves under the inverted aerofoil and in general delay the propagation of the bow shock between the model and the ground. Once the bow shock propagations passed underneath the models, the resulting flow field converged with free flight conditions and ground effect no longer had an impact on the supersonic aerodynamic performance of these models. Under some conditions, the combination of ground effect and the transient effects of acceleration or deceleration can cause dangerous lift and pitch conditions.
Understanding the challenges of implementing an effective Requirements Analysis process within an engineering R&D environment
(University of the Witwatersrand, Johannesburg, 2024) Lydall, Peter Wykeham; Law, Craig
Requirements Analysis is widely regarded within the Systems Engineering community as an activity that has a significant impact on project outcomes. However, it is an activity that is often overlooked or poorly executed. This report details the application of Yin (2003)’s Case Study Method to a single case, involving an engineering research and development group at a South African science council. The case study attempted to gain insights into the perceptions and attitudes of engineers and managers towards Requirements Analysis, that might explain why it is performed inconsistently or less effectively than it could be. Key findings include: that there is a poor understanding of what Requirements Analysis is; the importance of assigning a Requirements Analyst, in a dedicated role, with the appropriate level of engineering experience and Systems Engineering training, and a desire to perform the activity; the necessity of having a cost effective and tailored process which evolves over time.
Metallic Equivalent of Aircraft Landing Gear Using Composite Materials
(University of the Witwatersrand, Johannesburg, 2024) Kotze, Marius Hugo; Boer, Michael
There are two types of Light Sport Aircraft landing gear configuration. The taildragger and tricycle arrangement where the difference is specified by the position of the main landing gear. Shipment delay of the current Aluminium 7075 T6 landing gear has caused further delays in the manufacturing of the BushCat Light Sport Aircraft. Thus, a composite alternative was required which could be manufactured locally. The objective was to determine which locally available material was best suited as an alternative to the current Aluminium 7075 T6 design. This included estimation of the correct design loads acting on the BushCat aircraft main landing gear and to specify a composite alternative that could withstand these calculated design application loads. The loads that were used would be obtained from the ASTM F2245-14 regulations and EASA CS-23 amendments. The loads were validated by means of Finite Element Analysis and analytical calculations. Drop tests were also conducted by the company and image processing was used to compare the calculated deformations to the FEA results. This was used to validate the load and constraint applications in Ansys 2023 R2 software. The composite materials used for analysis were unidirectional epoxy e-glass wet layup and prepregs fibres. A coupon study was conducted on Aluminium 7075 T6 alloy and [0/90/90/0], [0/45/45/0], [0/90/45/0] layered unidirectional epoxy e-glass wet layup and prepreg coupons loaded under tension, compression, bending and torsion. The FEA results were validated using analytical calculations obtained from the Classical Lamination Theory. It was concluded that the unidirectional epoxy e-glass prepreg coupons were best suited as an alternative as better results in withstanding the applied load applications were obtained. The prepreg fibres also contained a lower void content in comparison to the wet layup fibres, thus increasing the fatigue life of the composite laminate as well as reducing the moisture absorption. The final composite landing gear was analysed using the Puck-failure criterion and it was found that after analysis and modifications were conducted, the newly designed composite landing gear could withstand the applied loads during limit load and ultimate load conditions without any fibre or inter-fibre failure in the strut of the landing gear. It was found that, failure had occurred in one of the fibre plies near the bolted regions of the axle section during ultimate (emergency) landing conditions and was thus concluded that the composite landing gear should still be inspected when attempting emergency landing at higher load conditions at an aircraft maximum take-off weight of 600 kg. The final composite landing gear design after modifications was 4.613 kg heavier than the Aluminium 7075 T6 landing gear. With regards to manufacturing the final composite landing gear a vacuum bagging process should be followed where the final vacuum bagging assembly containing the composite layup of the landing gear should be placed inside an oven or autoclave to start the curing process. Once the composite landing gear is cured, it could be machined into its final shape were non-destructive techniques such as ultrasound of thermography should be used to inspect the final composite landing gear for any air of volatile compounds withing the laminate. Static and dynamic destructive testing should also be used to validate if the final composite landing gear can withstand all landing conditions aircraft maximum weight without any fibre failure or delamination occurring.

4. Electronic Theses and Dissertations (ETDs) - Faculties submissions

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