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An implementation model: photovoltaic application for sustainable energy in South Africa
Get PDFSouth African electrical grid faces significant risks that the state produced electricity supply from electricity network to premises for consumption will not meet the electricity demand. Certain sectors of the economy and essential social services such as the hospitals, the telecommunications networks, and water companies are heavily impacted on by load management, through load shedding by rotating power outages or reducing power consumption from primary sources until demand decreases. Eskom, as the major electricity supplier in South Africa's aging infrastructure, with declining reliability, substandard quality coal and large gaps between generating capacity and demand, leaves the country vulnerable to electricity blackouts. The consequences of such power outages are devastating, but no single technology solution can meet the demand. Localised backup solutions such as solar power and battery backup limit the risk of power outages and provide power security during the periods of load shedding. Quantitative research method is pursued as a systematic survey to collect quantitative data by means of sampling and submitting online survey questionnaires. After receiving the data, statistical techniques were performed through structural equation modeling to analyse the structural relationship between the measured variables and the underlying variables. This research focuses on photovoltaic applications as a means of harnessing solar energy to convert solar energy into electricity. Solar panels consist of photovoltaic cells made of semiconductors or materials that respond to the action of photons of light. Energy availability to all can promote economic development and human well-being. Without the improvements in energy efficiency and development costs of new energy technologies such as photovoltaics, the global energy system will come under even more pressure. Therefore, changes in the global trend towards a decentralised low-carbon energy system are inevitable to ensure affordable, reliable and sustainable energy access for all. This research seeks to contribute to the present challenges that are facing South Africa’s electricity supply industry by increasing the energy mix of renewable energy as compared to the fossil fuel-based electricity supply.Thesis (DPhil) -- Faculty of Engineering, the Built Environment, and Technology, School of Built Environment and Civil Engineering, 202
A model for speech-driven lesson summary generation in a noisy educational environment
Get PDFThe application of Automatic Speech Recognition (ASR) technology for generating lesson transcripts and closed captions in the classroom has shown to improve the learning experience of people in disadvantaged student groups. This dissertation proposes a concept model for applying ASR technology in the educational environment for lesson transcription or closed captioning. The model aims further to bolster students’ secondary contact with the lesson content using keyword identification and subsequent association to generate a summary of the educator’s key points with reference to known course content material. To reinforce this concept, three core theoretical areas are discussed in this work, namely the existing applications of ASR technology in the classroom, the prominent machine-learning solutions that are capable of performing ASR, either for keyword spotting or for continuous speech recognition, and finally, the speech enhancement techniques used to mitigate the negative effects of environmental noise in the educational space. After a groundwork investigation into these three core theoretical areas, an initial model was created for incorporating an ASR system into the educational environment using the speech of the educator to drive the process of generating the lesson summary. After analysis for prototype development, the feasibility of developing a keyword-spotting system using South African speech data to train a machine-learning model revealed a number of challenges. Hence, it was decided that it would be more appropriate to implement a cloud-based ASR solution to establish proof of concept in a prototype system. In addition, the advent of a cloud-based ASR solution meant that a more reliable lesson transcript could be generated and, as a result, the direction of this work could move towards exploiting the utility provided by lesson transcription to generate a meaningful lesson summary. An initial prototype implementation was then developed based on the initial model using a cloud-based ASR approach. The final model presented in this work makes use of keyword identification in the transcription process, in collaboration with a course content database to identify known, educator-defined keyword terms during a lesson that are tied to relevant course content items for the specified lesson. As the model or prototype was improved and adapted, its counterpart was modified appropriately, ensuring that each reflected both the theoretical and practical aspects of the other. After a series of improvement cycles, a final version of the model was ascertained, supported by a performance evaluation of an acceptable prototype system. Ultimately, the prototype proved capable of generating a lesson summary, presented to students to bolster secondary contact with lesson content. This lesson summary provides students with a lesson transcript, but also helps them to monitor educator-defined keyword terms, their prevalence as communicated in the lesson by the educator, and their associations with educator-defined sections of course content. The prototype was developed with a modular approach so that its speech recognition component was interchangeable between CMU’s Sphinx and Google Cloud’ Speech-to-Text speech recognition systems, both accessed via a cloud-based programming library. In addition to the ASR module, noise injection, cancellation and reduction were also introduced to the prototype as a speech enhancement module to demonstrate the effects of noise on the prototype. The prototype was tested using different configurations of speech recognition- and speech enhancement techniques to demonstrate the change in accuracy of lesson summary generation. Proof of concept was established using the Google Cloud Continuous Speech Recognition System, which prevailed over CMU’s Sphinx and enabled the prototype to achieve 100,00% accuracy in keyword identification and subsequent association on noise-free speech, contrasted with a 96,93% accuracy in keyword identification and subsequent association on noise-polluted speech when applying noise cancellation.Thesis (MIT) -- Faculty of Engineering, the Built Environment, and Technology, School of Information Technology, 202
The promotion of the right to access adequate housing for street children in Kenya
Get PDFThis thesis explores the fundamental right to housing and shelter, recognised at national, regional, and international levels, focusing on its application to street children in Kenya. Despite constitutional provisions, street children in Kenya face exclusion from socio-economic interventions, particularly in the realm of housing and shelter. This exclusion stems from the absence of specific legislation addressing their unique needs. Existing laws, such as the Children Act, 2022 and the Housing Act, 2007 fall short of safeguarding the rights of street children, perpetuating discrimination based on economic status. The research examines international, regional, and national legal frameworks to uncover obstacles hindering street children from enjoying their legally protected human rights, including housing and shelter. Legal instruments such as the Universal Declaration of Human Rights, International Covenant on Economic, Social, and Cultural Rights, International Covenant on Civil and Political Rights, Convention on the Rights of the Child, the African Charter on Human and Peoples Rights, and the African Charter on the Rights and Welfare of a Child and policies like the Sustainable Development Goals 2030, the African Union Agenda 2063, and Agenda 2040 were considered. The research employed qualitative research methodology that included theoretical and non-empirical methods. It used a combination of descriptive, correlative, and limited comparative analysis of the status of street children in the East African Community State Parties of Tanzania, Uganda, and Rwanda, as well as South Africa. Theoretical perspectives, including human rights-based, vulnerability, othering, and capability theories, informed the discussions on improving the status of street children in Kenya. The study employed critical social justice and vulnerability theories to analyse how discrimination and prejudices in society can violate fundamental rights, particularly street children's rights. The findings of the study revealed the inadequate legal and institutional frameworks in promoting street children's rights in Kenya. The study referred to the best practices in the select East African Community State Parties and South Africa that Kenya can emulate to benefit street children and realise the right to shelter and adequate housing. The study recommends legal and policy reviews to protect street children's rights to adequate housing and shelter guided by constitutional and international standards.Thesis (LLD) -- Faculty of Law, 202
A process for integrated fitness and menstrual cycle data visualisations
Get PDFThe increase in female participation in sport has led to an increase in research reporting on the relationship between fitness and menstrual cycle (F&M) data. Fitness variables such as VO2 max and heart rate are influenced by menstrual hormones and change with the different phases of a cycle. People frequently track both their F&M data, to understand their long-term activity and their body’s changes during the different cycle phases. Both these data sets are tracked and visualised separately to help people understand their data, however little work has been done to visualise the relationship between the two data sets. A process that guides the creation of an integrated F&M visualisation does not exist. This research aimed to develop and adopt a process that could be used to successfully guide the creation of an integrated F&M visualisation. The study followed the Design Science Research Methodology (DSRM) to create a primary and secondary artefact – the process and instantiation thereof. The DSRM was applied in iterative cycles where the process was developed, instantiations created and evaluated by participants. To develop the process, existing data processing and visualisation processes were reviewed from literature, to assess their successes and shortcomings. The review of existing processes revealed what steps, and factors related to those steps, would need to be considered. The process review highlighted the importance of five process steps: planning, collection, access, integration, and visualisation. Once the conceptual process was designed, it was adapted for the goal of creating an integrated F&M data visualisation. Prior to implementation, the process was first tested in a pilot study to ensure its validity before involving participants in data collection. After the process pilot study, the final implementation of the process took place and participants were recruited. In the first step of the process, the different fitness data types that are influenced by the menstrual cycle, and vice versa, were identified through a literature review. In the second step, devices to be used for data collection were evaluated and tested through exploratory testing and review of user manuals available online. The third and fourth steps, access, and integration were informed by further exploratory testing and review of relevant literature. The fifth step, data visualisation, was guided by relevant studies, Hick’s law, and the Schema Theory. Two Iterations of DSR were conducted in two phases. Phase 1 (P1) was the instantiation of the planning, collection, access, and processing steps. Participants wore smartwatches while going about their daily lives and working out and tracked their menstrual cycle to collect data. P1data was used to create several instantiations of the process. The second phase (P2) was the instantiation the visualisation step. The final visualisations, resulting from the instantiations, were evaluated by participants in P2. The review notes were used to improve both the process and the final visualisations. Both P1 and P2 were repeated (iterated) twice. The recommended process can be used by anyone who wants to create an integrated F&M visualisation and was designed to be modular so that users could choose to follow the whole process or only specific steps. The findings of this research can provide guidance to users, developers and smartwatch manufacturers of what people’s preferences are for these integrated visualisations. It also provides guidance for those who wish to create their own visualisations without needing prior programming experience or knowledge, since easy to use, online visualisation tools are recommended. The process instantiations will assist people, especially women, to better understand their menstrual cycle and how it affects their physical well-being.Thesis (MCom) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 202
Photocatalytic reduction of CO2 into green fuels on microspherical nanocomposites comprising of CdS, TiO2, ZnFe2O4 semiconductors and heterojunctions
Get PDFHuman anthropogenic activities have led to an increase in CO2 levels resulting in global warming. There is a need to reduce CO2 levels in the atmosphere by capturing the gas and converting the captured CO2 into fuels. Photocatalytic conversion of CO2 into valuable products via photoreduction is a promising technique to reduce carbon dioxide using sunlight and water. Redox reactions between CO2 and water using photocatalysts offer an effective method of lowering CO2, which has detrimental effects on the environment. This dissertation reports the synthesis and characterization of five photochemical catalysts comprising of CdS, TiO2, ZnFe2O4 semiconductors and heterojunctions and their use as photocatalysts for the photocatalytic reduction of CO2 into green fuels. Mott−Schottky plot of TiO2, CdS and CdS/TiO2 confirmed the formation of n-type, n-type, and n-n type material respectively. The band gap of TiO2, CdS, and CdS/TiO2 obtained were 3.21,2.24, 2.04 eV, respectively, the combination of TiO2 and CdS resulted in the lowering of band gap energy which is favourable for photocatalytic reduction studies. XRD of TiO2, CdS and CdS/TiO2 provided relevant information about the various phase reflections of the photocatalysts, it also supported reports confirming the increase in crystallite size of TiO2 anatase phase upon calcination. Chemical environment of the various photocatalysts, such as Ti2p1/2, Ti2p3/2, O1s, Cd3d3/2, Cd3d5/2, S2p1/2 and S2p3/2 were observed in TiO2, CdS and CdS/TiO2. BET surface area of TiO2, CdS and CdS/TiO2 was also observed to be 2.9243, 4.0605, and 9.8450 m2g, respectively. Photocatalytic reduction of CO2 resulted in formic acid, formaldehyde, acetic acid, carbon monoxide, ethanol, and methanol after 12 h. Modification of CdS with TiO2 to form CdS/TiO2 produced high yield of formic acid (217.7 μmol/g) compared to CdS (8.7 μmol/g) and TiO2 (122.5 μmol/g). CdS had high yield of formaldehyde (20.4 μmol/g) and ethanol (57.8 μmol/g) compared to TiO2 (12.9, 3.6 μmol/g of formaldehyde and ethanol, respectively) and CdS/TiO2 (19.7 μmol/g and there was no detection of ethanol). TiO2 shows high yield of methanol (145.2 μmol/g) and is the only catalysts that produced carbon monoxide (52.2 μmol/g) compared to CdS (87.8 μmol/g of methanol) and CdS/TiO2 (50.2 μmol/g of methanol). A detailed elucidation of the various products was reported by means of nuclear magnetic resonance (NMR) spectrometer. ZnFe2O4 and CdS/TiO2/ZnFe2O4 were characterized and employed for photocatalytic reduction of CO2 in water. XRD and XPS confirmed the presence Fe (2+) and Fe (3+) in tetrahedral/octahedral and Zn (2+) in tetrahedral on ZnFe2O4 and CdS/TiO2. CdS/TiO2/ZnFe2O4 presented a lowered band gap of 1.98 eV due to the presence of ZnFe2O4 while the band gap of ZnFe2O4 obtained is 1.95 eV. The Mott-Schottky plots confirmed the conduction (2.81 and 2.59 eV) and valence band (–0.86 and –6.1 eV) of ZnFe2O4 and CdS/TiO2/ZnFe2O4 together with their junctions, respectively. ZnFe2O4 and CdS/TiO2/ZnFe2O4 are p-type and p-n type junctions, respectively. Photocatalytic reduction of CO2 under visible light for 12 h using CdS/TiO2/ZnFe2O4 hollow microspheres nanocomposites produced methanol (182.1 μmol/g), formic acid (1.9 μmol/g), formaldehyde (9.5 μmol/g), ethanol (67.1 μmol/g), and oxalic acid (38.9 μmol/g). Amongst the synthesized catalysts, CdS/TiO2/ZnFe2O4 produced high yield of methanol, ethanol, and oxalic acid.Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 202
Statistical learning methods for photovoltaic energy output prediction
Get PDFPredicting solar energy accurately is important for the integration of more renewable energy into the grid, which can help to alleviate the energy demand on traditional coal-powered sources in South Africa. This study aims to assess several statistical learning models to predict the energy output of a 1MW photovoltaic system installed on the Nelson Mandela University South Campus in Gqeberha. Weather data (including temperature, wind speed, wind direction, precipitation, air pressure, and humidity) and solar irradiance data (including global horizontal radiation, diffuse radiation, and direct radiation) are used to predict the energy output of this system using Artificial Neural Networks (ANN), Support Vector Machines (SVM), Multiple Linear Regression (MLR), and Regression Trees (RT). The performance of each of the models was compared and the results indicated that the ANN model performed best.Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 202
A qualitative review on the manner in which psychologists address language barriers in psychological testing with isiXhosa speaking clients
Get PDFA racially segregated culture historically influenced the growth of psychological testing and evaluation in South Africa. Thus, South Africa's multicultural and multilingual community poses difficulties for psychologists in their daily work. Most of the psychological tests used by psychologists are predominantly normed in either or only English/Afrikaans. Given the economic and professional resources required to develop new standardised tests for the broader South African population, the current status quo is set to continue for the foreseeable future. Consequently, language barriers pose a challenge when psychometric standardised tests are administered in a language that is different from that of the client, and as a result, psychologists must develop ways to enhance the fairness of these measures for their client base. The avenue of research that was explored is how psychologists overcome the language boundary when assessing clients who speak an indigenous first language, particularly isiXhosa. As such, this study explored this question through qualitative methods. Through purposive sampling, nine psychologists were invited to share their practical expertise on this topic, using semi-structured online interviews. The findings of this study suggested several core themes providing useful methods for other psychologists facing the same challenge, including the challenges with administering psychological tests with isiXhosa clients, the availability of standardised tests in the South African context, and the importance of determining the client’s language proficiency. Five themes with several sub-themes emerged from the study. The study contributes to the currently limited existing body of knowledge, and subsequently to the research area that this study explores - thus further providing guidelines that practitioners can employ when working with clients who are isiXhosa speaking.Thesis (MA) -- Faculty of Health Science, School of Behavioural & Lifestyle Sciences, 202
Elephant impacts on plant diversity and structure in the Shamwari Private Game Reserve
Get PDFMany African landscapes rely on processes such as fire, tree-fall and drought in addition to herbivores to initiate change across the landscape. In the Eastern Cape, elephant have a significant impact on the community structure and diversity of the vegetation they live in. This is most likely the case for the Albany Valley Thicket and azonal riparian vegetation of Shamwari Private Game Reserve, where browsing animals, particularly megaherbivores like the black rhinoceros and elephant, are the main cause of defoliation. The presence of large herbivores creates challenges when it comes to long-term sustainability and biodiversity of the vegetation in Shamwari. Vegetation monitoring provides essential information for effective management of megaherbivores not only in Shamwari but in many other similar reserves. The aim of this study was to design a monitoring plan for the Albany Valley Thicket and riparian vegetation in Shamwari using available vegetation metrics. The vegetation was measured in permanent plots (90 m line intercept analysis per plot) in the Albany Valley Thicket and riparian vegetation of Shamwari. Plot selection was based on thicket structural integrity using NDVI score as a proxy. In all plots, thicket structure was assessed using canopy heights measured every 50 cm along the line. Detrended correspondence analysis of the species abundance data suggested three distinct structural and compositional vegetation states for thicket and riparian vegetation: dense, intermediate and open. Significant relationships between NDVI and vegetation structural metrics across the condition states indicated that NDVI could be used as a proxy for vegetation condition. Vegetation compositional metrics, however, were not always correlated to NDVI and determining species diversity for the vegetation presents additional information useful for monitoring. The monitoring recommended for the reserve is to evaluate vegetation structural integrity annually in summer using NDVI. Areas of change could then be measured for diversity as well as for change in the abundance of selected plant indicator species. This information should be used to initiate management actions if unwanted change has occurred.Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 202
Investigation of the synthesis and characterisation of spiro orthocarbonates and heterocyclic orthocarbonates
Get PDFA series of mostly asymmetrical spiro orthocarbonates and heterospirocyclic derivatives of orthocarbonic acid was synthesized from 2,2-dichlorobenzodioxole and a number of difunctional reagents. A systematic study of the size of the chelate rings formed around the spirocentric carbon atom was conducted by selecting representative samples of aliphatic and aromatic diols. The feasibility and scope of potential starting materials used was expanded by reacting DCBD successfully with thiols. Molecular structures of these compounds were confirmed using diffraction studies on single crystals. All compounds were analyzed using multinuclear NMR. DFT calculations performed on the compounds allowed for the development of equations that can accurately predict 13C chemical shifts of SOCs. Furthermore, the experimental NMR spectroscopy gave rise to an increment shift system for the 13C NMR shifts allowing for further assignment of carbon atom positions in compounds with multiple possible bonding patterns.Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 202
Exploring the continued importance of technique in the co-production of art with A.I.
Get PDFn Plato’s Republic, artists are criticised for their perceived lack of rationality, since “art encourages and appeals to emotion,” insofar as “its ruling principle is the passions, which in a happy and well-ordered life must be controlled by reason;” indeed, on this basis, “the aesthetic experience” is even said to be “a psychological anarchy, [and] an orgy of misrule” (Collingwood, 1925: 156). However, this reification of reason in Plato’s hypothesized world,1 informed as it was by static hierarchy, has remained dissonant with the path of history toward entropy, as evinced by the chaotic flux of postmodernity. Certainly, this is exemplified in our own postmodern world, characterized as it is by ever greater degrees of disintegration into diversity, as the economic, social, and geo-political orders established in the mid-twentieth century are challenged and transformed into new paradigms through the increasing multiplicity of demands being made on them (Fowlie & Sills, 2011: 120-121). Accordingly, far from being a source of delusion and dissimilation, it could equally be argued that, collectively and individually, artists’ works reflect this kaleidoscopic trace of time more truthfully than the lens of reason, precisely because life – like art – is also largely psychological anarchy and an orgy of misrule. And within this dynamic environment, the reflections of artists, in turn, assume their value, as traces of what, for want of a better term, will henceforth be referred to as living dialogical time. That is, from this perspective, artists are not the political problem Plato suggested them to be, but rather as a whole comprise a reflection of the living dialogical time that, today, recognises itself collectively as humanity. However, while art has always involved material marks, digitality has recently changed this requirement, in ways which have raised a series of important and difficult questions for the world of art. That is, digitality has changed the wall of the cave into the digits of ones and zeros, which are eradicated at the click of an icon, only to be reconstructed at the click of an icon. Thus, the interface between art and digitality involves the former being presented with increasing opportunities for dynamism, but only at the expense of its materiality – insofar as such dynamism requires art to transition to cyber-virtual platforms. But in this regard, it must be remembered that, by definition, an icon is something which connects us to what cannot ever be represented, because it is beyond our everyday living reality, in an atemporal plane.Thesis (MA) -- Faculty of Humanities, School of Language, Media and Communication, 202