Photocatalytic reduction of CO2 into green fuels on microspherical nanocomposites comprising of CdS, TiO2, ZnFe2O4 semiconductors and heterojunctions
- Authors: Mudau, Rendani Julian
- Date: 2024-04
- Subjects: Heterojunctions , Chemistry, Inorganic , Nanochemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64214 , vital:73665
- Description: Human 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, 2024
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- Date Issued: 2024-04
Photoluminescence and electroluminescence imaging of PV devices
- Authors: Roodt, Roelof Petrus
- Date: 2024-04
- Subjects: Photoluminescence , Biosensors
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64333 , vital:73676
- Description: Luminescence imaging has become a particularly useful and valuable tool for the characterisation of photovoltaic devices. This study entailed the design, construction, and optimisation of a system for the electroluminescence (EL) and photoluminescence (PL) imaging of various solar cell devices. The system can perform EL and PL imaging of solar cells of different cell technologies and materials systems, including Si, perovskite, and triple-junction concentrator solar cells. This required appropriate electrical power supplies for carrier injection for EL imaging and optical excitation for PL imaging. The different materials systems also required wavelength appropriate filters for PL imaging. In addition, the system utilized a temperature-controlled sample stage and was placed in a chamber for environmental control and isolation of UV radiation from laboratory. In addition to optimization of imaging conditions, luminescence images need to be optimized to facilitate detailed analysis and the application of appropriate algorithms to extract device parameters and hence generate device parameter images of the devices under investigation. For EL imaging, two power supplies were used to inject current into the solar cells. The reason for the two power supplies is that the first power supply had a current range of ± 1 A and an applied voltage capability of ± 21 V. This was used for the smaller solar cells. It was also convenient to use as the power supply could also measure the injected current and applied voltage and digitally store it with the images. For the larger solar cells, a second power supply was utilized, which could inject current into the samples in the range of ± 12 A at an applied voltage of ± 40 V. To measure the current and voltage of the power supply provided, two digital multimeters were utilized. For acquiring images, the same camera was used for EL and PL imaging. The sensor used in the camera is a silicon CMOS sensor. For PL imaging, four light emitting diode (LED) boards, consisting out of sixty-four LED’s, per board, of four different wavelengths, were used to optically excite the solar cells. The four wavelengths emitted by the LED’s were chosen to match the bandgaps of the different solar cell devices investigated. The LEDs were powered with a multi-channel constant voltage power supply, where the current could be varied. The Si solar cell is a 156 x 156 mm commercial solar cell. The perovskite solar module is a 40 x 40 mm module, which consists out of six cells connected in series. The triple-junction concentrator solar cell has a dimension of 10 x 10 mm which consists of three junctions staked on top of one another. These three layers consist of indium gallium phosphate (InGaP), indium gallium arsenide (InGaAs) and germanium (Ge). To capture EL and PL images of these various solar cell devices, filters of specific wavelengths were placed in front of the camera to isolate the light generated by the different devices. In addition to isolating the luminescence observed from the solar cells, an image correction procedure was adapted from literature, to be applicable to acquiring luminescence images of these various solar cells. As there are a range of factors which influence the quality and clarity of the luminescence images, i.e., chromatic aberration, diffraction, and absorption depth, to name a few, the wavelength dependency of these factors was investigated. This was done by acquiring a point spread function (PSF) for each of these devices and then using these PSF's together with a deconvolution algorithm to correct the luminescence images. The PSF was acquired by fitting a point source emission image to a function that includes exponential and Gaussian terms. The point source image was obtained by placing a black piece of vinyl with a pinhole in it over the solar cell. To communicate with all the various devices and to acquire images at various intensities a LABVIEW program was written. This was used then used to control the power supplies, digital multimeters, camera, and the LED's. This allowed for the user to specify at what points along the current-voltage (I-V) curve data points needed to be measured together with the luminescence images captured. For PL imaging the intensity of the LED's was then also adjusted according to user specified values. The system was utilised to acquire EL images of the Si solar cell, EL and PL images of the perovskite solar cell and EL images of the InGaP and InGaAs layers in the triple-junction concentrator solar cell. With the correction procedure utilised in this study, it was seen that the image quality and clarity improved, compared to the conventional way of capturing luminescence images. These statements are supported by the results obtained for the series resistance maps of the Si solar cell and the perovskite solar module, as the series resistance maps obtained from the corrected luminescence images have less noise and more detail compared to the results from the raw luminescence images. From the EL images captured for the two layers of the triple junction concentrator, it was clear that the intensity profile of the two layers is different, as the intensity for the InGaP layers was that the device had bright edges and darker intensity on the interior where exactly the opposite was observed for the InGaAs layer, having a bright interior and darker edges. This is most likely due to the opto-electric coupling of these layers withing the triple junction solar cell. For the series resistance images obtained for the Si solar cell, it is observed that at lower carrier injection, the series resistance is lower compared to higher carrier injection levels. This result can also be influenced by the increase in cell temperature with the increase in injected carriers. The series resistance maps obtained from the perovskite EL images shows an interesting result. As the perovskite solar cell has degraded, three of the six cells have optically inactive regions, showing lower luminescence intensities. The series resistance of the other three cells are much lower compared to these cells that have inactive regions under low injection conditions. As the injection level increases, it is seen that the series resistance values of five of the six cells become comparable to one another. With regards to the PSF, it was found that using a bandpass filter in front of the lens reduced to amount of spreading observed from a single point source across the detector. Furthermore, there is a strong wavelength dependency in the PSF as the severity increased with increase in the emission wavelength of the solar cells under investigation.In this study an opto-electrical characterisation system was constructed to acquire PL and EL images of various solar cell technologies. In addition to this, a range of factors that influence the quality of these images were investigated and used in the image correction procedure to correct the images for all these cell technologies. It was shown that the correction procedure works for all three of the technologies investigated in this study, and all these factors showed a strong wavelength dependency. These corrected luminescence images together with current-voltage (I-V) data was then used to determine characteristic parameters of a one-diode model of the various PV devices. This was not only achieved, but it also clearly indicated that all the correction procedures need to be considered to obtain a clear and accurate representation of the actual PV device. This has a major influence on the understanding and improvement of these PV devices. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
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- Date Issued: 2024-04
Preparation and Investigation of coumarin-based chemosensors towards sensing of ions using UV studies in aqueous systems
- Authors: Kotze, Tyla
- Date: 2024-04
- Subjects: Chemistry, Analytic , Water chemistry , Ionic solutions , Aquatic ecology , Geochemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64116 , vital:73654
- Description: Humanity's unrelenting expansion has shown little regard for the environment, and this has resulted in tons of toxic heavy metal cations and anions being released into the environment through industrial, agricultural, electronic, and mining dumping. The release of these toxic heavy metals can cause diseases and sometimes lead to death, especially in third-world countries with low-income that reside in informal settlements, who suffer the most. Furthermore, the release of these toxins eventually finds their way back into the environment through bioaccumulation in fish, plants and animals. Although there is an ever need for the growth of these industries; low-cost, sensitive, selective, and organic-based sensors is a positive step forward in highlighting the need for environmental restoration and remediation, whilst striving to avoid unnecessary disease and death through this development. In this project, coumarin-based chemosensors for the detection of cationic and anionic species in aqueous and organic media are described. This project involves the synthesis of six different coumarin-based ether derivatives (E2-E5) and coumarin-based ester derivatives (H1-H2). FT-IR, 1H NMR and 13C NMR were used to confirm the structures of all sensors. The abilities of these novel compounds as chemosensors for detection of cations and anions were investigated using UV-vis analysis. These compounds displayed a favourable interaction with Fe2+ and Fe3+ ions with an increase in absorbance. Ether derivatives E2-E5 did not display any degree of selectivity or sensitivity towards the chosen anions. It was found that in the presence of FeCl2, sensors H1 and H2 displayed a degree of selectivities and further investigations were therefore carried out. From the titration experiments, the limit of detection, limit of quantification and association constants were determined. Job’s plot analyses were performed to determine the binding ratios, which was supported by Benesi-Hildebrand studies. The binding ratio between the sensors and metal cations during complexation was found to be 1:1. Reversibility studies were carried out using EDTA to determine whether the sensors could be reused. Molecular Modelling studies were used to determine the most preferred binding sites. Lastly, real-life application screenings were also run to determine if the sensors will be able to be used in real-life scenarios. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
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- Date Issued: 2024-04
Prevalence of red blood cell alloantibodies in healthy blood donors: A retrospective study
- Authors: Bada, Thandolwethu Sarafina
- Date: 2024-04
- Subjects: Blood--Transfusion , Blood donors , Red blood cell alloantibodies
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63688 , vital:73586
- Description: Background: Blood transfusion is one of the essential supporting therapies in the management of patients and all efforts must be geared towards ensuring greater blood safety. There are studies on the prevalence of red blood cell alloantibodies in numerous transfused patients. However, no research has been done on the population of healthy first-time donors in South Africa who donates blood for transfusion. Red blood cell alloantibodies may be present in the donated units and potentially lead to transfusion reactions or to decreased survival of transfused RBCs. Therefore, it is necessary to know the prevalence of alloantibodies in donors and the clinical significance. Aims and objectives: The aim of this study is to determine the prevalence and identity of red blood cell alloantibodies in healthy first-time blood donors in the South African population, as well as to identify them, with the goal of improving blood safety and transfusion support for patients. Materials and methods: This retrospective and observational study investigates healthy first-time blood donors in the South African population over a five-year period, from January 2015 to December 2019. ABO typing and Rh typing were performed using the fully automated immunohaematology analyser BECKMAN COULTER PK7300 (Danaher Corporation, Brea, California). Erytra Eflexis automated system (8-column DG Gel cards) (Diagnostic Grifols, Barcelona, Spain) was used for antibody screening and antibody identification was performed using the RBC 11 Identisera Diana panel sheet. Approval was obtained from the Ethics Committees of Nelson Mandela University, South African National Blood Services and Western Province Blood Services prior to commencement of the study. Results: A total of 497 711 healthy first-time donors, consisting of 209 604 (42%) males and 288 107 (58%) females, were evaluated for irregular antibodies. The maximum number of donors belonged to the age group 18 to 29. Antibody screening results were positive in 849 donors from the entire population investigated, and 603 were RBC alloantibodies with an overall prevalence of 0.12%. The most frequent RBC alloantibody identified was anti-M from the MNS blood group systems, being present in 129 blood donors. Conclusion: The prevalence of RBC alloantibodies in the donor population in the study was 0.12% (603/497 711). As the inclusion criteria was limited, larger studies examining at all donors (first-time and repeated donations) are needed to determine the actual prevalence of alloantibodies in the population of South African donors. , Thesis (MHSc) -- Faculty of Health Sciences, School of Clinical Care & Medicinal Sciences, 2024
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- Date Issued: 2024-04
Project management deficiencies in construction implemented projects in the Eastern Cape
- Authors: Mbanga, Abulele Zakhe
- Date: 2024-04
- Subjects: Project management -- South Africa -- Eastern Cape , Construction industry -- South Africa -- Eastern Cape -- Management , Construction workers -- South Africa -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64640 , vital:73819
- Description: The problems that crop up in each project are unique to that project. They can also be avoided or minimised as inherent weaknesses. Project managers lack strategic considerations when running projects. This is primarily dependent on individuals’ implementation of project management. The concern is how project managers implementing construction projects can be corrected to remove management deficiencies. In recent years, project management has become an essential part of organisations. This is because of the changing nature of managing organisations due to technological advancement and a complex, competitive global marketplace (Nguyen, Nguyen, Le-Hoai & Dang, 2015). Projects require huge capital outlays. As such, it is crucial to have good project management practices to deliver value for money projects and programmes. Therefore, the importance of good project management practices cannot be ignored by corporate managers, as failure destroys shareholders’ value and, in the private sector, can significantly affect the various stakeholders associated with projects. However, studies indicate that companies in the private sector in the Eastern Cape sometimes fail to complete projects. (Fabian & Amir, 2015). Project management deficiencies in the Eastern Cape are as high as those of other provinces in South Africa, if not higher (Saad, 2022). The primary reasons for project management deficiencies are project planning failure, scope management failure, resource management failure, and communication management failure (Liu, Louw, Ngugi & Smith, 2011). Therefore, using different success and failure criteria, this study aims to measure the impact of project management deficiencies in communication management, project planning, scope change, and resource management. Project management deficiencies in construction projects implemented in recent years have been one of the topics most discussed by academics, practising managers, the private and public sectors, and many social commentators worldwide. , Thesis (MSc) -- Faculty of Engineering, the Built Environment and Technology, School of Built Environment and Civil Engineering, 2024
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- Date Issued: 2024-04
Public policy considerations and the enforcement of restraint of trade agreements.
- Authors: Tinyane, Nthabeleng
- Date: 2024-04
- Subjects: Trade agreement , Restraint of trade , Commercial policy
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66297 , vital:74493
- Description: A restraint of trade is often incorporated into a contract of employment, stipulating that an employee is restricted from working in the same industry or sector as the employer for a specified period of time. Such a provision is aimed at protecting an employer's proprietary interests, such as trade connections and secrets, which may potentially benefit a competitor unfairly and unlawfully. In South Africa, the principles associated with restraints of trade are rooted in common law. The landmark judgment in Magna Alloys & Research (SA) (Pty) Ltd v Ellis clarified the legal position regarding agreements in restraint of trade in South Africa. Prior to the judgment, there were considerable differences in the approaches adopted by the courts in relation to provisions in restraint. These differences primarily centered around the Roman-Dutch law notion, which holds that contracts voluntarily entered into ought to be honored (pacta sunt servanda), and the English law approach that contracts in restraint of trade are prima facie unenforceable. The court in Magna held that the position in South Africa with regard to agreements in restraint of trade is that each agreement should be examined with regard to its own circumstances to determine whether the enforcement of such an agreement would be contrary to public policy. This means that while restraints of trade are generally enforceable, they must be reasonable and not against the public interest. The reasonableness of the restraint is assessed based on factors such as the duration and geographic scope of the restraint, the nature of the employee’s role, and the interests of the employer that the restraint seeks to protect.. , Thesis (LLM) -- Faculty of Law, Department of Mercantile law (Labour Law), 2024
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- Date Issued: 2024-04
Quantify the shift in critical strain energy density for a dynamic loaded S355J2 weld section by small punch testing
- Authors: Snyman, Ross
- Date: 2024-04
- Subjects: Materials -- Testing , Materials -- Microscopy , Mechanical engineering
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64830 , vital:73927
- Description: The potential of using “critical strain energy density” as an indicator to detect material degradation on fatigue-loaded components, where the stress amplitude was gradually increased, was investigated by applying the small punch test methodology. Small punch discs were extracted from four fatigue specimens. Discs were extracted from two zones within the fatigue specimens: the heat-affected zone of a shield metal arc welded butt joint, as well as from parent metal plate area. Each fatigue specimen having been exposed to a different stress amplitude but equal number of fatigue cycles of 20 million. This allowed the development of a Small Punch Test results database, permitting the calculation of material properties by using a Finite Element Analysis inverse method. Critical strain energy values did not reveal any conclusive shift or correlation for discs extracted from the HAZ. This is mainly attributed to variance in the grain structure for HAZ samples. For discs extracted from parent metal, a decreasing trend in strain energy density value was noted in relation to an increase in the fatigue test stress amplitude. This observed change was a clear indication of the potential for using “Strain Energy Density”, as extracted from this test methodology, as a ranking tool for quantifying the extent of degradation of in-service components. The application of this study demonstrated the ability to monitor and predict material degradation for a given stress range over the expected life of a cyclically loaded component utilizing strain energy density results. This is useful, particularly in heavy industries where structures and large-scale components are used beyond their original design life. , Thesis (MEng) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 2024
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- Date Issued: 2024-04
Quantifying the impact of the spatio-temporal variability of land use/land cover on surface run-off generation and groundwater recharge in the luvuvhu river catchment area as a study area
- Authors: Ramuhovhi, Dakalo Ndivhuwo Stella
- Date: 2024-04
- Subjects: Remote sensing , Geographic information systems , Groundwater flow
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64322 , vital:73675
- Description: Assessing the spatio-temporal dynamics of land use land cover (LULC) change on hydrological response is vital for catchment sustainability and developing proper management strategies. The study aimed to assess the spatiotemporal effects and implications of LULC dynamics on surface runoff in the Luvuvhu River Catchment, Limpopo Province, using the Soil and Water Assessment Tool (SWAT) model. Satellite images of Landsat 5-thematic mapper and Landsat 8 operational land imager for the years 1990 and 2021 were used to explore the characteristics of LULC for this study by adopting the maximum likelihood (ML) supervised classification method. Five LULC classes were classified in this study; namely, water, built-up area, bare surface, dense vegetation, and sparse vegetation. The classification results show good accuracy values in the range of 76% (1990) and 84% (2021) with overall kappa of 63.8% and 72.8% for 1990 and 2021, respectively. For the purpose of this study, integration of geospatial technique and SWAT model were configured to operate at a monthly time interval over a span of 34 years, specifically from 1979 to 2013 to simulate surface runoff. The SWAT simulation process was executed using a digital elevation model, soil, LULC, and weather data. The analysis of LULC for 1990 and 2021 runoff modelling, it was found that, the runoff depth increased gradually from 3249 mm to 5162.5 mm during 1990 and 2021 LULC change, respectively. The R2, ENS, PBIAS, and RSR values for the calibration and the validation were 0.81 and 0.76, and 0.72 and 0.68, 0.64 and 0.58, 0.54 and 0.63 respectively. These values indicate good correlation between the observed and simulated stream flow data Therefore, suitable and timely management measures must be taken by policy decision-makers to enable sustainable development and to protect the catchment’s natural resources in order to reduce the severity of the changes. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2024
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- Date Issued: 2024-04
Reasonable accommodation for persons with disabilities at the workplace
- Authors: Addae, Charles Kwadwo
- Date: 2024-04
- Subjects: Employment Equity Act 55 of 1998 , Disability rights , Disability in the work place
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66140 , vital:74420
- Description: In recent years, there has been a growing recognition of the importance of inclusivity and equal opportunities for individuals with disabilities in the workplace. This thesis aims to contribute to this discourse by examining the issue of reasonable accommodation for disabled employees, with a specific focus on the South African context. The International Labour Organisation (ILO) and the United Nations (UN) Convention on the Rights of Persons with Disabilities provide important frameworks for promoting inclusivity and equal opportunities for disabled individuals in employment. These global standards emphasise the need for reasonable accommodation, which refers to the adjustments and modifications made to the work environment or job duties to enable disabled employees to perform their tasks effectively. In South Africa, the Employment Equity Act 55 of 1998 (EEA) and the Labour Relations Act 66 of 1995 (LRA) serve as the legal framework for addressing disability rights in the workplace. These acts outline the obligations of employers to provide reasonable accommodation and protect disabled employees from discrimination. By analysing the specific provisions within the EEA and LRA, this research aims to gain insights into how South Africa addresses and implements reasonable accommodation measures. By synthesizing the perspectives of the ILO, the UN Convention, and the South African legal framework, this study aims to provide a comprehensive understanding of the challenges, successes, and potential areas for improvement in achieving workplace inclusivity for individuals with disabilities. It will examine the barriers that disabled employees face in accessing reasonable accommodation, such as attitudinal barriers, lack of awareness, and financial constraints. Additionally, it will explore the strategies and initiatives that have been successful in promoting inclusivity and equal opportunities for disabled individuals in the South African workplace. , Thesis (MSc) -- Faculty of Law, Department of Mercantile law, 2024
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- Date Issued: 2024-04
Reconstructing the fire history and palaeoenvironment at Thyspunt, Southern Cape Coast, Eastern Cape
- Authors: Ntsondwa, Asithandile
- Date: 2024-04
- Subjects: Paleoecology -- South Africa -- Eastern Cape , Paleoclimatology -- South Africa -- Eastern Cape , Sedimentation analysis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64277 , vital:73671
- Description: This study aims to comprehensively understand the palaeoenvironments at Thyspunt in the Eastern Cape, a subregion of the Cape Floristic Region, through fire reconstruction and sediment analyses. Given the fire-dependent nature of the dominant vegetation (fynbos) in the area, there is a need for fire reconstructions and an understanding of the broader ecological dynamics within the southern Cape coastal region (SCCR). This research focused on reconstructing the fire regimes using sedimentary micro- and macrocharcoal from a sediment core (TP-1) extracted from the Langefonteinvlei wetland at Thyspunt, covering the last 5000 years. The charcoal fragments were separated into three size classes, with two falling under microcharcoal (size class 1: 10 – 100 μm and size class 2: 100 – 150 μm) and fragments greater than 150 μm representing macrocharcoal. The sedimentary profile of the TP-1 sequence was characterised based on loss on ignition and x-ray fluorescence analyses to provide better insight into the area's geological and geomorphic setting, climate history, and sediment properties. The results from the geochemical data revealed consistently high calcium carbonate composition throughout the sequence with a decrease in concentration at ~2000 cal. yr BP, 1300 cal. yr BP, and from 500 cal. yr BP to recent years. The sediments had relatively high organic content during the last 500 years. The geochemical data also indicate that the sediments are associated with shallow marine and near-shore depositional environments with a sharp increase in fine material at about 4500 cal. yr BP representing a low-energy environment. High fire activities occur around 4000 cal. yr. BP and from 1500 cal. yr BP till present, with former fire activities more likely associated with increased wildfires (driven by climate change) and the latter possibly reflecting human influence at that time. Microcharcoal fragments (size class 1: 10 – 100 μm) had higher concentrations than the other size fragments. This study underpins the importance of a multiproxy study to enrich our understanding of fire histories in Thyspunt and contributes to broader regional insights. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2024
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- Date Issued: 2024-04
Regulation of sexual harassment at the workplace in Namibia
- Authors: Kayama, Ohms Moven
- Date: 2024-04
- Subjects: Workplace Sexual Harassments , Labour Law , Sex discrimination in employment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/64695 , vital:73862
- Description: Many Namibians are driven by the need for income and economic sustainability, pushing them to seek employment and make a living for themselves. However, what appears to be just participating in economic activities can be a risky and traumatic experience for some workers. For years, many have had to balance their job responsibilities while enduring discrimination, bullying, violence, and harassment in the workplace. Sexual harassment has been a major problem in the workplace, with women being the primary targets and victims. Studies have shown that gender inequality is one of the leading causes of sexual harassment in the workplace. Within the above context, this treatise aimed at answering to what extent Namibia's legislative framework regulates sexual harassment in the workplace. Namibia's legal framework was tested against the global instruments to answer the question. It was found that Namibia's legislative framework does regulate sexual harassment. However, some several gaps were identified. First, there is ambiguity and scope of legal definitions as the current definition of sexual harassment in section 5(7)(b) of the LA is not comprehensive enough. It fails to explicitly include both "quid pro quo" and "hostile environment" sexual harassment. This ambiguity could hinder victims' ability to seek justice and the legal system to prosecute offenders effectively. Second, there is an inefficacy of reporting structures, which is a significant barrier. Victims often face unclear and inefficient procedures, contributing to underreporting and unresolved cases. Developing straightforward, accessible, and efficient reporting mechanisms is crucial. Third, the absence of comprehensive workplace policies against sexual harassment exacerbates the issue. While developing a Code of Good Practice is positive, its implementation status and effectiveness remain uncertain. Another gap relates to the protection for whistleblowers and victims, as a lack of adequate legal protection for whistleblowers and witnesses discourages reporting. Strengthening legal protections can empower more individuals to come forward. The gaps identified were developed while comparing Namibia’s legislative framework to South Africa to determine whether lessons can be learned as it was found that lessons could be learned. Further recommendations is that Namibia should establish a single OHS legislation to address workplace sexual harassment by standardising policies and procedures across various industries, improving reporting standards to measure the occurrence of sexual harassment incidents, and developing a Code of Good Practice regulating sexual harassment. Lastly, it is acknowledged that Namibia's ratification of the Violence and Harassment Convention, 2019 (No. 190) is a welcomed development and shows a positive commitment in its intention to curb sexual violence in the workplace. , Thesis (LLM) -- Faculty of Law, 2024
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- Date Issued: 2024-04
Relationship management in all-boys fee-paying public Schools in the Eastern Cape, South Africa: experiences and perspectives of LGBTQ alumni
- Authors: Mahlangu, Nhlakanipho
- Date: 2024-04
- Subjects: Single-sex schools -- South Africa -- Eastern Cape , Sex differences in education -- South Africa -- Eastern Cape , Customer relations -- Management , Sexual minorities -- Education -- Research -- South Africa -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65108 , vital:74024
- Description: This study explores the perspectives and experiences of LGBTQ alumni of all-boys’ schools in the Eastern Cape. The context of increased competition between schools in the education sector and the importance of inclusion within the sector necessitated a study to investigate the extent to which relationship management is conducted with an orientation towards LGBTQ inclusion in all-boys’ schools in the Eastern Cape. Student protests in South Africa over the past 10 years have expanded concerns about student belonging beyond the widely studied lenses of race and class. A growing body of literature and wider discourse emphasises student belonging as a challenge in the South African education sector. Marginalised students continue to experience educational spaces negatively. LGBTQ student experiences in the South Africa are characterised by violence and ostracisation, thus warranting further investigation and inquiry. The study locates itself in the intersections between gender and sexual diversity and economic citizenship in the broader discourse of school inclusivity. A qualitative research approach was employed, making use of semi-structured, in-depth individual interviews. The sample was derived from alumni of all-boys’ schools in the Eastern Cape through snowball sampling. Ten LGBTQ-identifying alumni of boys’ schools in the Eastern Cape were interviewed. The findings reveal the need to question the extent to which LGBTQ alumni can enjoy the fullness of the value proposition of all-boys’ schools, and what can be done to ensure LGBTQ belonging. The findings of this study concur with existing literature about LGBTQ experiences. Participants defined their school experiences as exclusionary and characterised by fear of failing to assert themselves in a hypermasculine school environment. LGBTQ alumni of all-boys’ schools in the Eastern Cape view relationship management as under-utilised as a tool to facilitate LGBTQ belonging. Instead, relationship management is used to affirm those who fit the mould of the quintessential ‘old boy’ network, by defining the masculine behaviours that learners in all-boys’ schools are compelled to aspire towards. , Thesis (MCom) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2024
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- Date Issued: 2024-04
Relationship Management in All-Boys’ Fee-paying Public Schools in the Eastern Cape, South Africa : Experiences and Perspectives of LGBTQ Alumni
- Authors: Mahlangu, Nhlakanipho
- Date: 2024-04
- Subjects: Gay men , Teenage boys , Public schools -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62237 , vital:72364
- Description: This study explores the perspectives and experiences of LGBTQ alumni of all-boys’ schools in the Eastern Cape. The context of increased competition between schools in the education sector and the importance of inclusion within the sector necessitated a study to investigate the extent to which relationship management is conducted with an orientation towards LGBTQ inclusion in all-boys’ schools in the Eastern Cape. Student protests in South Africa over the past 10 years have expanded concerns about student belonging beyond the widely studied lenses of race and class. A growing body of literature and wider discourse emphasises student belonging as a challenge in the South African education sector. Marginalised students continue to experience educational spaces negatively. LGBTQ student experiences in the South Africa are characterised by violence and ostracisation, thus warranting further investigation and inquiry. The study locates itself in the intersections between gender and sexual diversity and economic citizenship in the broader discourse of school inclusivity. A qualitative research approach was employed, making use of semi-structured, in-depth individual interviews. The sample was derived from alumni of all-boys’ schools in the Eastern Cape through snowball sampling. Ten LGBTQ-identifying alumni of boys’ schools in the Eastern Cape were interviewed. The findings reveal the need to question the extent to which LGBTQ alumni can enjoy the fullness of the value proposition of all-boys’ schools, and what can be done to ensure LGBTQ belonging. The findings of this study concur with existing literature about LGBTQ experiences. Participants defined their school experiences as exclusionary and characterised by fear of failing to assert themselves in a hypermasculine school environment. LGBTQ alumni of all-boys’ schools in the Eastern Cape view relationship management as under-utilised as a tool to facilitate LGBTQ belonging. Instead, relationship management is used to affirm those who fit the mould of the quintessential ‘old boy’ network, by defining the masculine behaviours that learners in all-boys’ schools are compelled to aspire towards. v ABSTRACT The findings illustrate that the culture of silence around non-confirming sexuality is sustained in the post-schooling relationship management life-cycle and results in the absence of the LGBTQ customer voice in the drafting of school strategy and policy. LGBTQ alumni who speak out about controversial issues often face admonition from their former teachers and peers. LGBTQ alumni criticise the relationship management of their former schools for the over-emphasis on fundraising and the complete absence of discussions on diversity. LGBTQ alumni are therefore marginalised in the process of value co-creation, as LGBTQ alumni feel they will never be viewed as legitimate collaborators by their former schools. The suggested recommendations emerging from this study include the need to codify school policies that speak specifically to LGBTQ marginalisation. Furthermore, schools must endeavour to make specific enquiries into LGBTQ student experiences and include LGBTQ concerns in wider school discourse. , Thesis (Ma) -- Faculty of Business and Economic Sciences, 2024
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- Date Issued: 2024-04
Resignation in employment Law
- Authors: Kheswa, Zimasa
- Date: 2024-04
- Subjects: Resignation , Employees--Dismissal , Disciplinary--actions
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65296 , vital:74089
- Description: This treatise provides a comprehensive analysis of the legal framework governing resignations in South Africa. It examines the statutory provisions, regulations, and general principles that underpin employment termination, with a focus on voluntary resignation, constructive dismissal, and termination during disciplinary proceedings. Through an analysis of important case law, the treatise explores the practical challenges and legal ambiguities employers and employees face when navigating the resignation process. The treatise also conducts a detailed comparative legal analysis of resignation laws, focusing on the United Kingdom’s approach and how it contrasts with and could potentially inform legal practices in South Africa. Based on the findings, the treatise proposes several recommendations for improving the legal framework governing resignations in South Africa, including enacting clearer statutory guidelines, encouraging consistent judicial rulings, adopting best practices from the United Kingdom’s legal system, and facilitating stakeholder engagement. By implementing these recommendations, South Africa can create a more coherent legal framework for resignations, promoting fairness, certainty, and efficiency in employer-employee relations. , Thesis (LLM) -- Faculty of Law, Department of Mercantile law, 2024
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- Date Issued: 2024-04
Risk Management as a nexus to Ameliorate Citizen Centricity in the Western Cape Provincial Government
- Authors: Micketts, David
- Date: 2024-04
- Subjects: Risk management , Corporate governance -- South Africa -- Case studies , Public administration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63345 , vital:73259
- Description: This study aims to explore how risk management can be applied by the Western Cape Provincial Government to enhance citizen centricity in the Province. The Provincial Departments and Public Entities in this province are applauded for achieving satisfactory audit results in recent financial years from the Auditor-General South Africa. Despite the aforementioned, service delivery protests remain ongoing, which is indicative of citizen dissatisfaction and distress. Ensuring an effective, efficient, and transparent risk management system is mandatory, as prescribed by relevant legislation in South Africa and citizens are entitled to specific rights articulated in the Bill of Rights chapter of the Constitution. Therefore, it is essential that risk management – which forms part of good governance – be embedded by leadership and in processes to ultimately constrain risks which may hinder citizen centricity. Six chapters are included in this research paper. A qualitative approach was adopted, which considered a comprehensive review of literature, and a desktop analysis was performed. Secondary data and information sources were consulted and applied, without the participation of human subjects, for the purposes of primary data collection. Research findings were presented utilising thematic content analysis. It was found during the study that the Western Cape Government risk management framework is flexible to constrain various categories of risk and embraces local and global best practices in the risk management and citizen-focused governments arenas. Furthermore, the framework advocates and drives collaboration between a myriad of role-players, both internal and external to the organisation, to collectively manage risks posed to the achievement of the defined goals, objectives and priorities. To this end, the study was pursued through the lenses of a New Public Management (NPM) paradigm as well as deliberative democracy theory and public governance theories and administrative practices. , Thesis (MPA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2024
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- Date Issued: 2024-04
Role of community pharmacies in the management of diabetic foot ulcers in South Africa
- Authors: Greyling, Cosette
- Date: 2024-04
- Subjects: Foot -- Ulcers -- Treatment , Wounds and injuries -- Treatment , Diabetes -- Complications
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63846 , vital:73619
- Description: Appropriate wound care and management are essential to prevent complications in patients with diabetic foot ulcers (DFUs). It is important to evaluate if patients are getting the necessary therapeutic treatment and counselling at community pharmacies. The primary aim was to determine the role of community pharmacies in South Africa in the management of DFUs. This study used a mixed-method research design combining both quantitative and qualitative research methodologies. In 2023 a questionnaire was distributed to a sample of 823 community pharmacists in South Africa with questions regarding DFUs. Data from the questionnaire were analysed and used in the next phase of the study, which was focus group discussions (FGDs). The FGDs were conducted with a group of pharmacy stakeholders. The response rate for the questionnaire was 18.95% (n=156). Only 105 respondents completed the questionnaire. Majority of the respondents (n=45) were located in Gauteng province, practising in corporate pharmacies (n=88) in urban areas (n=104). Majority of respondents (n=73) indicated that they did not have a clinic inside their pharmacies and 46 respondents indicated that they had a nurse employed in the pharmacy. Most frequently seen chronic wounds in community pharmacies were diabetic wounds and surgical wounds. Majority (n=71) of respondents indicated that they have not attended additional training on DFUs. Respondents indicated that they most often used the internet and other healthcare providers as information resources regarding DFUs. The results also indicated that community pharmacists would like to have more training regarding advanced wound care and that pharmacists do have a role to play when managing DFUs. During two FGDs, two main themes emerged namely “Community pharmacists encounter various challenges when treating patients with DFUs” and “There is a gap in training for community pharmacists in treating DFUs”. The focus group discussion (FGD) results complemented the questionnaire survey results. Since there is limited research published in South Africa on the role of community pharmacies managing DFUs, this study indicated that there is a need for additional training on DFUs for pharmacists working in community pharmacies in South Africa. , Thesis (M.Pharm) -- Faculty of Health Science, School of Clinical Care & Medicinal Sciences, 2024
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- Date Issued: 2024-04
Rural teachers’ experiences during covid-19 pandemic: lessons learnt to cope with future emergencies
- Authors: Dlambewu, Amanda
- Date: 2024-04
- Subjects: COVID-19 (Disease) -- Social aspects -- South Africa , Rural schools -- South Africa , Teachers -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63945 , vital:73629
- Description: This study focused on challenges faced by rural teachers during the COVID-19 pandemic, with the intention of using the outcomes to develop a framework that could assist with coping with similar challenges in future emergencies. The study was situated in the interpretivist paradigm. A qualitative approach was employed using interviews and a focus group discussion. Bronfenbrenner’s ecological theory and the theory of rurality were used as lenses to explore and interpret the challenges that rural teachers experienced during the COVID-19 pandemic. The study's findings reveal that teachers faced the following challenges: mental health, adaptability, impact on personal life, safety, and work environment challenges. Furthermore, the study also found that teachers used the following coping mechanisms to deal with the challenges during the pandemic: adherence to rules and regulations, pastoral services, support from friends and family, collaboration, and physical activity. Finally, after applying both the theory of rurality and Bronfenbrenner's ecological theory to the findings, a framework was developed to assist in coping with future emergencies. , Thesis (MEd) -- Faculty of Education, Post Graduate Education, 2024
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- Date Issued: 2024-04
Scenarios for re-imagining the digital landscape of South African organizations
- Authors: Watson, Storm Brandon
- Date: 2024-04
- Subjects: Education, Higher -- South Africa , Cyberinfrastructure , Sustainability -- Technological innovations
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/66116 , vital:74356
- Description: The primary objective of this study was to develop and evaluate scenarios for re-imagining the digital landscape of South African organizations. This study aimed to re-imagine the future of South African organizations, focusing on developing a framework for the re-imagination of Higher Education Institutions (HEIs) to create a generic framework that could be incorporated by other organizations or sectors in South Africa to re-imagine their digital landscapes. The Council of Higher Education (CHE) in South Africa identifies the core functions of HEIs as teaching and learning, research and innovation, and community engagement. For this study, primary data was collected through the analysis of the 2021 annual reports and official websites of the 26 public universities in South Africa, which are known as HEIs. An environmental scan was conducted through content analysis of these sources to identify current trends and key uncertainties affecting the institution's core functions of teaching and learning, research and innovation, as well as community engagement concerning their digital landscape of South African HEIs, with separate scenarios crafted for each function. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2024
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- Date Issued: 2024-04
Seagrasses in Mozambique: distribution, people’s perceptions and restoration best practice
- Authors: Mabuto, Manuela Elisa Manuel Amone , Hollander, Johan
- Date: 2024-04
- Subjects: Seagrasses -- Mozambique , Seagrasses -- Southern Hemisphere , Coastal zone management -- Mozambique , Restoration ecology -- Mozambique
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/64126 , vital:73655
- Description: This thesis investigated the restoration of seagrass meadows and their associated biodiversity thus contributing to their conservation and to people's well-being. A mixed methods approach was used, and results presented in five chapters. Chapter I is a general introduction to the study outlining relevant information, research objectives and hypotheses. Chapter II investigates coastal community’s perceptions on the role of seagrass ecosystems, local impacts of coastal erosion and the need for seagrass restoration in Mozambique. It showed that there is a high awareness of the studied communities to seagrass importance for their livelihoods. Communities supported restoration and identified community engagement as a fundamental component for a successful implementation of restoration projects in their area. Chapter III conducted a mapping inventory for seagrass using open access data sources and investigated change detection in seagrass extent in southern Mozambique using Satellite imagery. In addition, Unmanned Aerial Vehicles (drones) were used to map seagrass to the species level at Inhaca Island. The results showed that seagrass habitats have been losing extent in recent years mainly in Bairro dos Pescadores at northwest Maputo Bay, due to sedimentation from flooding and inappropriate gleaning / clam collection practices. Around Inhaca Island seagrass extent has changed in response to natural causes and from anthropogenic disturbance near the main village and port area. For the first time for this area drones were used to rapidly and effectively acquire high- resolution data for detailed seagrass mapping and monitoring. The different mapping approaches were critically analyzed, and a way forward discussed. In Chapter IV, two different field experiments were conducted simultaneously. One, mimicked disturbance of meadows in terms of digging to collect clams, a common practice in northeastern Maputo Bay to assess the time of natural recovery and another replanted Zostera capensis using different plug sizes. The results indicated that once anthropogenic impacts are ceased, Z. capensis meadows are restored 12 months after impact exclusion. There was a 75% survival rate for the mechanical plug restoration approach; positive implications for seagrass transplantation projects that are both time consuming and financially costly. It was clear from the study that a combination of both impact exclusion and active restoration is needed for seagrass survival. Chapter V investigated the influence of seagrass restoration on the abundance and diversity of macroinvertebrates. After two years of observations, replanted seagrass areas had not recovered compared to natural established seagrass beds. However, a strong linear relationship existed between the abundance of seagrasses and the quantity of associated macrofauna species. Chapter VI provided recommendations on better ways to perform seagrass restoration and management. The main findings of this thesis provide new knowledge on the mapping of seagrass on a local to a regional scale as well as on better restoration practice of the seagrass Zostera capensis, an IUCN Red List vulnerable species. Communities’ perceptions on seagrass were investigated contributing to an understanding of the socio-ecological conservation and management of these critical and yet threatened ecosystems. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2024
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- Date Issued: 2024-04
Self-attentive vision in evolutionary robotics
- Authors: Botha, Bouwer
- Date: 2024-04
- Subjects: Evolutionary robotics , Robotics , Neural networks (Computer science)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63628 , vital:73566
- Description: The autonomy of a robot refers to its ability to achieve a task in an environment with minimal human supervision. This may require autonomous solutions to be able to perceive their environment to inform their decisions. An inexpensive and highly informative way that robots can perceive the environment is through vision. The autonomy of a robot is reliant on the quality of the robotic controller. These controllers are the software interface between the robot and environment that determine the actions of the robot based on the perceived environment. Controllers are typically created using manual programming techniques, which become progressively more challenging with increasing complexity of both the robot and task. An alternative to manual programming is the use of machine learning techniques such as those used by Evolutionary Robotics (ER). ER is an area of research that investigates the automatic creation of controllers. Instead of manually programming a controller, an Evolutionary Algorithms can be used to evolve the controller through repeated interactions with the task environment. Employing the ER approach on camera-based controllers, however, has presented problems for conventional ER methods. Firstly, existing architectures that are capable of automatically processing images, have a large number of trained parameters. These architectures over-encumber the evolutionary process due to the large search space of possible configurations. Secondly, the evolution of complex controllers needs to be done in simulation, which requires either: (a) the construction of a photo-realistic virtual environment with accurate lighting, texturing and models or (b) potential reduction of the controller capability by simplifying the problem via image preprocessing. Any controller trained in simulation also raises the inherent concern of not being able to transfer to the real world. This study proposes a new technique for the evolution of camera-based controllers in ER, that aims to address the highlighted problems. The use of self-attention is proposed to facilitate the evolution of compact controllers that are able to evolve specialized sets of task-relevant features in unprocessed images by focussing on important image regions. Furthermore, a new neural network-based simulation approach, Generative Neuro-Augmented Vision (GNAV), is proposed to simplify simulation construction. GNAV makes use of random data collected in a simple virtual environment and the real world. A neural network is trained to overcome the visual discrepancies between these two environments. GNAV enables a controller to be trained in a simple simulated environment that appears similar to the real environment, while requiring minimal human supervision. The capabilities of the new technique were demonstrated using a series of real-world navigation tasks based on camera vision. Controllers utilizing the proposed self-attention mechanism were trained using GNAV and transferred to a real camera-equipped robot. The controllers were shown to be able to perform the same tasks in the real world. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
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- Date Issued: 2024-04