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A model for automated topic spotting in a mobile chat based mathematics tutoring environment

  • Authors: Butgereit, Laura Lee
  • Date: 2012
  • Subjects: Mobile communication systems in education , Mathematics -- Study and teaching , Tutors and tutoring -- Mathematics
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:9809 , http://hdl.handle.net/10948/d1013741
  • Description: Systems of writing have existed for thousands of years. The history of civilisation and the history of writing are so intertwined that it is hard to separate the one from the other. These systems of writing, however, are not static. They change. One of the latest developments in systems of writing is short electronic messages such as seen on Twitter and in MXit. One novel application which uses these short electronic messages is the Dr Math® project. Dr Math is a mobile online tutoring system where pupils can use MXit on their cell phones and receive help with their mathematics homework from volunteer tutors around the world. These conversations between pupils and tutors are held in MXit lingo or MXit language – this cryptic, abbreviated system 0f ryting w1ch l0ks lyk dis. Project μ (pronounced mu and indicating MXit Understander) investigated how topics could be determined in MXit lingo and Project μ's research outputs spot mathematics topics in conversations between Dr Math tutors and pupils. Once the topics are determined, supporting documentation can be presented to the tutors to assist them in helping pupils with their mathematics homework. Project μ made the following contributions to new knowledge: a statistical and linguistic analysis of MXit lingo provides letter frequencies, word frequencies, message length statistics as well as linguistic bases for new spelling conventions seen in MXit based conversations; a post-stemmer for use with MXit lingo removes suffixes from the ends of words taking into account MXit spelling conventions allowing words such as equashun and equation to be reduced to the same root stem; a list of over ten thousand stop words for MXit lingo appropriate for the domain of mathematics; a misspelling corrector for MXit lingo which corrects words such as acount and equates it to account; and a model for spotting mathematical topics in MXit lingo. The model was instantiated and integrated into the Dr Math tutoring platform. Empirical evidence as to the effectiveness of the μ Topic Spotter and the other contributions is also presented. The empirical evidence includes specific statistical tests with MXit lingo, specific tests of the misspelling corrector, stemmer, and feedback mechanism, and an extensive exercise of content analysis with respect to mathematics topics.
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  • Date Issued: 2012

A model for managing user experience

  • Authors: Mashapa, Job
  • Date: 2013
  • Subjects: Technological innovations -- Management , User interfaces (Computer systems)
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:9826 , http://hdl.handle.net/10948/d1020765
  • Description: New innovative products are being designed while the user interface of existing products is constantly being revamped to give them a new look. All this is an effort to bring a satisfactory interacting experience for the user. However, in most cases users do not feel that they experience that benefit. The introduction of a new product, or the enhancement of the functionality and user interface of an existing product, often faces criticism and brings resistance to the acceptance and usage of the product by the users. Therefore, the change in user interface or introduction of new products does not only affect the business processes but also the lifestyles of the users, as well as their overall user experience. One of the most important components for the success of any product is a positive user experience. User experience refers to the subjective feeling of the user that results from their interaction or intention to interact with a product in order to perform a specific task in a specific environment. When the user interface and functionality of a product match the expectations of the users and make the users effective and efficient, feel safe and attain some level of self-worth from using or possessing the product, their interaction with the product becomes more satisfactory. User experience practitioners are in agreement that a change to the user interface influences the user experience of the people when interacting with the product; hence it affects change in the user experience of the people. A vast body of literature exists on the methods for evaluating user experience as well as on the principles that are aimed at guiding the design of products for a positive user experience. However, there is a lack of a means to manage this change in user experience that results from the changes in the features of the user interface or the product functionalities. This inadequacy opens up the potential for integrating change management principles in order to manage user experience. However, existing change management principles do not address the user experience aspects when managing change. Following the above premise, this study focused on the development of a model for managing user experience: the User Experience Management Model (UXM2). The UXM2 infers its components from the disciplines of user experience and change management. Its uniqueness is seated in its people-centred approach that aims to effect a free-will change in the individuals towards a long-term positive user experience. The proposed model further aims to promote the voluntary acceptance of a product, which is contrary to the mandatory change that is guided by the policies of the organization, as discussed in the study. The UXM2 was developed from a thorough argumentation of literature on user experience and change management. The components that were required for development of the model were identified from literature, and were evaluated for their relevance by means of academic publications in subject domain international conferences. The academic publications underwent double-blind peer review with subject domain experts. The model was evaluated for its relevance and potential applicability through interviews and discussions with subject domain experts. The subject domain experts consist of user experience practitioners and academic professionals in the domain of HCI. The subject domain experts also evaluated the model by means of an evaluation tool comprising of a Likert scale rating of the proposed components and related activities for managing user experience. The target users of the UXM2 are user experience practitioners and product developers who aim to promote a sustainable long-term positive user experience for the people interacting with their products. The UXM2 is aimed at being used for the design of products that are meant for institutional use, personal use, mandatory use and optional use. It is believed that adoption of the UXM2 will promote acceptance of the product by users, with an associated sustainable positive long-term user experience.
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  • Date Issued: 2013

A model for mobile, context-aware in-car communication systems to reduce driver distractions

  • Authors: Tchankue-Sielinou, Patrick
  • Date: 2015
  • Subjects: Automobiles -- Safety measures , Context-aware computing , Mobile communication systems
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/4144 , vital:20556
  • Description: Driver distraction remains a matter of concern throughout the world as the number of car accidents caused by distracted driving is still unacceptably high. Industry and academia are working intensively to design new techniques that will address all types of driver distraction including visual, manual, auditory and cognitive distraction. This research focuses on an existing technology, namely in-car communication systems (ICCS). ICCS allow drivers to interact with their mobile phones without touching or looking at them. Previous research suggests that ICCS have reduced visual and manual distraction. Two problems were identified in this research: existing ICCS are still expensive and only available in limited models of car. As a result of that, only a small number of drivers can obtain a car equipped with an ICCS, especially in developing countries. The second problem is that existing ICCS are not aware of the driving context, which plays a role in distracting drivers. This research project was based on the following thesis statement: A mobile, context-aware model can be designed to reduce driver distraction caused by the use of ICCS. A mobile ICCS is portable and can be used in any car, addressing the first problem. Context-awareness will be used to detect possible situations that contribute to distracting drivers and the interaction with the mobile ICCS will be adapted so as to avert calls and text messages. This will address the second problem. As the driving context is dynamic, drivers may have to deal with critical safety-related tasks while they are using an existing ICCS. The following steps were taken in order to validate the thesis statement. An investigation was conducted into the causes and consequences of driver distraction. A review of literature was conducted on context-aware techniques that could potentially be used. The design of a model was proposed, called the Multimodal Interface for Mobile Info-communication with Context (MIMIC) and a preliminary usability evaluation was conducted in order to assess the feasibility of a speech-based, mobile ICCS. Despite some problems with the speech recognition, the results were satisfying and showed that the proposed model for mobile ICCS was feasible. Experiments were conducted in order to collect data to perform supervised learning to determine the driving context. The aim was to select the most effective machine learning techniques to determine the driving context. Decision tree and instance-based algorithms were found to be the best performing algorithms. Variables such as speed, acceleration and linear acceleration were found to be the most important variables according to an analysis of the decision tree. The initial MIMIC model was updated to include several adaptation effects and the resulting model was implemented as a prototype mobile application, called MIMIC-Prototype.
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  • Date Issued: 2015

A model for privacy-aware presence management in mobile communications

  • Authors: Ophoff, Jacobus Albertus
  • Date: 2011
  • Subjects: Mobile communications systems , Mobile communication systems -- Management
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:9757 , http://hdl.handle.net/10948/1354 , Mobile communications systems , Mobile communication systems -- Management
  • Description: As humans we find communicating natural and compelling. Over the centuries we have created many innovations which enable and improve communication between people; during the past decade mobile phone networks have brought about a technological revolution in this area. Never before have people been so connected to one another. Today we have the ability to communicate with almost anyone, anytime, anywhere. Our increased connectivity and reachability also leads to new issues and challenges that we need to deal with. When we phone someone we expect an instant connection, and when this does not occur it can be frustrating. On the other hand it is equally disruptive to receive a call when one is busy with an important task or in a situation where communication is inappropriate. Social protocol dictates that we try to minimize such situations for the benefit of others nearby and for ourselves. This management of communications is a constant and difficult task. Using presence – which signals a person’s availability and willingness to communicate – is a solution to this problem. Such information can benefit communication partners by increasing the likelihood of a successful connection and decreasing disruptions. This research addresses the problem of staying connected while keeping control over mobile communications. It adopts a design-science research paradigm, with the primary research artifact being a model for privacy-aware presence management in mobile communications. As part of the model development knowledge contributions are made in several ways. Existing knowledge about the problem area is extended through a quantitative analysis of mobile communications management. This analysis uses a novel survey, collecting useful empirical data for future research. This includes how people currently manage their communications and what features they expect from a potential “call management” system. The examination and use of presence standards, as a foundation for the model, provides a comparison of the main presence technologies available today. A focus on privacy features identifies several shortcomings in standards which, if addressed, can help to improve and make these standards more complete. The model stresses the privacy of potentially sensitive presence information. A unique perspective based on social relationship theories is adopted. The use of relationship groups not only makes logical sense but also assists in the management of presence information and extends existing standards. Finally, the evaluation of the model demonstrates the feasibility of a practical implementation as well the ability to extend the model in next generation mobile networks. Thus the model presents a solid foundation for the development of future services. In these ways the proposed model contributes positively towards balancing efficient mobile communications with the need for privacy-awareness.
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  • Date Issued: 2011

A molecular genetic assessment of the population structure and variation in two inshore dolphin genera on the east coast of South Africa

  • Authors: Smith-Goodwin, Jacqueline Anne
  • Date: 1998
  • Subjects: Dolphins -- South Africa Variation (Biology) Dolphins -- Genetics Population genetics Bottlenose dolphin -- South Africa Sousa -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4007 , http://hdl.handle.net/10962/d1004067
  • Description: Coastal dolphins on the South African east coast are threatened by degradation and loss of habitat as a result of increasing coastal development, industrial effluent and agricultural runoff. In addition, dolphins off the coast of KwaZulu-Natal have, for more than four decades, been heavily exploited through unchecked incidental capture in shark nets set at 45 beaches. In light of the high rate of mortality and apparent depletion of both species, the persistence of bottlenose (Tursiops truncatus) and humpback (Sousa chinensis) dolphins in that region has been questioned. Genetic variation in south east African dolphin populations was determined as a means of assessing the fitness of the populations and their resilience to demographic disturbances. Furthermore, in order to determine the effects of continued mortality on the KwaZulu-Natal subpopulations, it was necessary to determine whether they are open or closed to immigration from the adjacent East Cape region, which represents a relatively unstressed region, characterised by a lack of shark nets and less intensive coastal activities. Genetic variation and differentiation in the maternal genome was assessed by determining the sequence of the first 400 bases of the mtDNA control region in bottlenose and humpback dolphins from KwaZulu-Natal and the East Cape. Nuclear variation and differentiation was estimated at six microsatellite loci and compared with earlier estimates determined from allozyme electrophoresis. Random amplified polymorphic DNA (RAPD) was assessed as a means of identifying population subdivisions and diagnostic population markers. Both bottlenose and humpback dolphins on the South African east coast are characterised by low nuclear and organellar genetic variation, consistent with a possible genetic bottleneck, the inferred date of which coincides with the onset of the last glacial period. Genetic variation in South African bottlenose dolphins was lower than that reported elsewhere for the species, while an intraspecific comparison supported lower genetic variation in South African humpback dolphins than in humpback dolphins sampled off Hong Kong. An analysis of molecular variance (AMOVA), performed on mtDNA haplotype frequency data indicated, for both species, significant genetic subdivision, concordant with geographic location. The data suggested female bottlenose dolphins demonstrate regional philopatry, displaying limited movement between KwaZulu-Natal and the East Cape. Female humpback dolphins tend towards strict local philopatry, with significant maternal differentiation evident both within and between regional subdivisions. Differentiation in microsatellite allele frequencies was also demonstrated between KwaZulu-Natal and the East Cape for both species, suggesting that the movement of male bottlenose and humpback dolphins may also be restricted. Nonetheless, considerably higher nuclear gene flow estimates suggested that males of both species represent the principal vectors of gene dispersal. The implications of historically low genetic variability and population subdivision in South African dolphins are important in view of the current rate of mortality in KwaZulu-Natal. The persistence of coastal dolphin populations relies on their ability to recover following a bottleneck event. Continued removal of demographically important age-sex classes such as occurs in shark nets, may not only further reduce the genetic variation, but would ultimately deplete dolphin populations in KwaZulu-Natal beyond a sustainable number, resulting in eventual local extinction. The differentiation of the two regions implies that, in the event of local extinction occurring, dolphins, particularly females, from adjacent regions will not readily re-colonise the area. This would result in fragmentation of the south east African populations and ensure reproductive isolation from neighbouring populations on the east African coast.
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  • Date Issued: 1998

A morphogenic and laminated system explanation of position-practice systems and professional development training in mainstreaming education for sustainable development in African universities

  • Authors: Agbedahin, Adesuwa Vanessa
  • Date: 2016
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/584 , vital:19972
  • Description: This research focuses on Education for Sustainable Development (ESD) in Higher Education Institutions (HEIs), particularly in Africa. It explores the roles and practices of these institutions, especially their professionals, in the Anthropocene era where increasing concern for contemporary environmental and sustainability issues and risks emerge. The study presents a longitudinal case study of institutions and participants of the Swedish/African/Asian International Training Programme (ITP) on ESD in Higher Education (HE), who are mostly university educators. This thesis however focuses on African ITP participants only. At a macro level, the research sought to examine how African university educators have contributed to the United Nations Decade of Education for Sustainable Development (UNDESD) through their participation in the ITP (which is a change oriented professional development training programme on ESD) and the associated ESD ‘change projects’. The change projects are ITP participants’ direct attempts to mainstream environment and sustainability issues, concerns, and concepts into core university functions and practices: teaching, research, community engagement, and management operations and policy engagement. At a meso level the study sought insight into how educators in national institutions were supported by sub-regional and regional initiatives, institutions and organisations, including the Mainstreaming of Environment and Sustainability in African (MESA) Universities Partnership programme, especially an initiative supported by the Southern African Development Community Regional Environmental Education Programme to provide (limited) seed funding to three southern African universities to establish what are known as ‘MESA Chairs’, with dedicated time and support for MESA activities in their universities . At a micro level, this research sought to investigate how the position-practice systems and the ITP shape (enable or constrain) effective ESD mainstreaming in higher education, and how the morphogenetic approach and laminated system can be used to understand and explain these dynamics and their relations with meso and macro level engagements. The research sought to understand these dynamics through empirical investigations using survey questionnaires, interviews, document analysis and field visits. The research is constituted as theoretical, conceptual, methodological and analytical exploration using a singular and nested case study research approach, underlaboured by a critical realist ontology, and drawing on a social learning epistemology and social realist morphogenetic interpretive lens. In particular, ontological depth was sought via critical realist laminated system explanation. See Chapter Two for details. This study was carried out in three phases. Phase one encapsulates the investigation of all ITP ESD in higher education alumni who were Asian and African participants from the inception of the ITP to its completion, over a six-year period (2008-2013). This included 280 academics from Asia and Africa in 35 countries in Asia and Africa from 106 institutions in Asia and Africa with their 139 change projects. The outcome of phase one of the research is only included in this thesis as an appendix (see Appendix 3; Agbedahin & Lotz-Sisitka, 2015). However, this phase provided and formed the foundational data that was expanded in phases two and three for the purpose of this study. Phase two of this research concentrated on a less broad population of research participants comprising only all African ITP alumni, from all regions in Africa. The overall data collection and analysis included 162 academics in 23 African countries from 66 institutions with their 81 change projects. The aim was to investigate and provide a morphogenetic explanation of their change projects and how the relationship between participants’ positions and practices (and that of others) may influence ESD mainstreaming in universities. The outcome of this phase two investigation is presented in Chapter Four. In phase three, (nested) case studies of Swaziland, Zambia, and Botswana (in the southern Africa region), which included all the ESD ITP HE participants therein and the three corresponding EE/ESD MESA Chairs, were developed. The population sample in this phase three therefore contained 20 academics, from six institutions with their nine change projects. This phase was characterised by field trips to these countries and in-depth data collection and analysis in order to investigate and deepen the morphogenetic explanations of their change projects and how the relationship between participants’ positions and practices (and that of others) have indeed influenced the ESD mainstreaming in universities. The outcome of this phase three research is presented in Chapters Five, Six and Seven. The final Chapter Eight of this thesis focuses on the seven scalar laminated system perspective and reflections on this research and discussion of these perspectives for supporting the mainstreaming of ESD in African higher education institutions and more specifically in the three case countries and respective institutions presented in Chapters Five, Six, and Seven. The seven scalar laminated system is presented in relation to the position-practice system, and draws on morphogenetic social realist and social learning theory to provide perspective on the actual change processes. Chapter Eight also includes a discussion on social learning and its implication for ESD mainstreaming, and provides recommendations for further research. The outcome of the theoretical exploration underpinning this study provided a potential model for understanding ESD learning and change processes that are facilitated by professional development training programmes in the context of ESD in HE. This study also provides a model for appraising educational changes in time and in space, especially in relation to ESD, or the types of changes that can be brought about by professional development interventions such as those provided by the ITP and how they can be tracked, monitored and documented. For the field of professional or academic development in higher education, this research highlights the significance of the relationship between position-practice systems, professional development interventions and institutional transformation. For the field of ESD in higher education, this study shows the need for in-depth consideration of the position-practice system and sphere of influence of change agents and related stakeholders in and around their institutions in the design and development of professional development programmes. It further sheds light on the laminated system of factors that contextually constrain and/or enable effective ESD mainstreaming at individual, collective, institutional, national, regional and global levels.
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  • Date Issued: 2016

A multi-threading software countermeasure to mitigate side channel analysis in the time domain

  • Authors: Frieslaar, Ibraheem
  • Date: 2019
  • Subjects: Computer security , Data encryption (Computer science) , Noise generators (Electronics)
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/71152 , vital:29790
  • Description: This research is the first of its kind to investigate the utilisation of a multi-threading software-based countermeasure to mitigate Side Channel Analysis (SCA) attacks, with a particular focus on the AES-128 cryptographic algorithm. This investigation is novel, as there has not been a software-based countermeasure relying on multi-threading to our knowledge. The research has been tested on the Atmel microcontrollers, as well as a more fully featured system in the form of the popular Raspberry Pi that utilises the ARM7 processor. The main contributions of this research is the introduction of a multi-threading software based countermeasure used to mitigate SCA attacks on both an embedded device and a Raspberry Pi. These threads are comprised of various mathematical operations which are utilised to generate electromagnetic (EM) noise resulting in the obfuscation of the execution of the AES-128 algorithm. A novel EM noise generator known as the FRIES noise generator is implemented to obfuscate data captured in the EM field. FRIES comprises of hiding the execution of AES-128 algorithm within the EM noise generated by the 512 Secure Hash Algorithm (SHA) from the libcrypto++ and OpenSSL libraries. In order to evaluate the proposed countermeasure, a novel attack methodology was developed where the entire secret AES-128 encryption key was recovered from a Raspberry Pi, which has not been achieved before. The FRIES noise generator was pitted against this new attack vector and other known noise generators. The results exhibited that the FRIES noise generator withstood this attack whilst other existing techniques still leaked out secret information. The visual location of the AES-128 encryption algorithm in the EM spectrum and key recovery was prevented. These results demonstrated that the proposed multi-threading software based countermeasure was able to be resistant to existing and new forms of attacks, thus verifying that a multi-threading software based countermeasure can serve to mitigate SCA attacks.
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  • Date Issued: 2019

A multiscale remote sensing assessment of subtropical indigenous forests along the wild coast, South Africa

  • Authors: Blessing, Sithole Vhusomuzi
  • Date: 2015
  • Subjects: Forests and forestry -- South Africa -- Remote sensing , Forest conservation , Remote sensing , Geographic information systems
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:10677 , http://hdl.handle.net/10948/d1021169
  • Description: The subtropical forests located along South Africa’s Wild Coast region, declared as one of the biodiversity hotspots, provide benefits to the local and national economy. However, there is evidence of increased pressure exerted on the forests by growing population and reduced income from activities not related to forest products. The ability of remote sensing to quantify subtropical forest changes over time, perform species discrimination (using field spectroscopy) and integrating field spectral and multispectral data were all assessed in this study. Investigations were conducted at pixel, leaf and sub-pixel levels. Both per-pixel and sub-pixel classification methods were used for improved forest characterisation. Using SPOT 6 imagery for 2013, the study determined the best classification algorithm for mapping sub-tropical forest and other land cover types to be the maximum likelihood classifier. Maximum likelihood outperformed minimum distance, spectral angle mapper and spectral information divergence algorithms, based on overall accuracy and Kappa coefficient values. Forest change analysis was made based on spectral measurements made at top of the atmosphere (TOC) level. When applied to the 2005 and 2009 SPOT 5 images, subtropical forest changes between 2005-2009 and 2009-2013 were quantified. A temporal analysis of forest cover trends in the periods 2005-2009 and 2009-2013 identified a decreasing trend of -3648.42 and -946.98 ha respectively, which translated to 7.81 percent and 2.20 percent decrease. Although there is evidence of a trend towards decreased rates of forest loss, more conservation efforts are required to protect the Wild Coast ecosystem. Using field spectral measurements data, the hierarchical method (comprising One-way ANOVA with Bonferroni correction, Classification and Regression Trees (CART) and Jeffries Matusita method) successfully selected optimal wavelengths for species discrimination at leaf level. Only 17 out of 2150 wavelengths were identified, thereby reducing the complexities related to data dimensionality. The optimal 17 wavelength bands were noted in the visible (438, 442, 512 and 695 nm), near infrared (724, 729, 750, 758, 856, 936, 1179, 1507 and 1673 nm) and mid-infrared (2220, 2465, 2469 and 2482 nm) portions of the electromagnetic spectrum. The Jeffries-Matusita (JM) distance method confirmed the separability of the selected wavelength bands. Using these 17 wavelengths, linear discriminant analysis (LDA) classified subtropical species at leaf level more accurately than partial least squares discriminant analysis (PLSDA) and random forest (RF). In addition, the study integrated field-collected canopy spectral and multispectral data to discriminate proportions of semi-deciduous and evergreen subtropical forests at sub-pixel level. By using the 2013 land cover (using MLC) to mask non-forested portions before sub-pixel classification (using MTMF), the proportional maps were a product of two classifiers. The proportional maps show higher proportions of evergreen forests along the coast while semi-deciduous subtropical forest species were mainly on inland parts of the Wild Coast. These maps had high accuracy, thereby proving the ability of an integration of field spectral and multispectral data in mapping semi-deciduous and evergreen forest species. Overall, the study has demonstrated the importance of the MLC and LDA and served to integrate field spectral and multispectral data in subtropical forest characterisation at both leaf and top-of-atmosphere levels. The success of both the MLC and LDA further highlighted how essential parametric classifiers are in remote sensing forestry applications. Main subtropical characteristics highlighted in this study were species discrimination at leaf level, quantifying forest change at pixel level and discriminating semi-deciduous and evergreen forests at sub-pixel level.
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  • Date Issued: 2015

A narrative, child-participatory study of domestic mobility within grandmother-headed households in the Eastern Cape, South Africa

  • Authors: Lotter, Jaclyn Oehley
  • Date: 2017
  • Subjects: Women heads of households South Africa Eastern Cape , Poor women South Africa Eastern Cape , Migration, Internal South Africa , Poverty South Africa , HIV infections Social aspects South Africa , HIV infections Economic aspects South Africa , AIDS (Disease) Social aspects South Africa , AIDS (Disease) Economic aspects South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/7678 , vital:21285
  • Description: The movement of adults and children between households in South Africa is a tradition entrenched by apartheid state policies and fuelled by poverty and HIV/AIDS. Children affected by domestic mobility include not only orphans, but those whose families are struggling financially or are deprived of income through illness or death. One example of domestic mobility is the redistribution of children through grandmother-headed households. While domestic mobility has been researched from a number of different academic perspectives, there is scanty psychological literature on the subject, and a gap around children’s experiences of their own mobility. Children’s roles and agency in their mobility, and how these are shaped by their environments, social relations and resilience, are not considered. This research aimed to explore the meanings that domestic mobility had in the lives, identity constructions and personal narratives of South African children currently residing in grandmother-headed households in the Eastern Cape. This was achieved through a narrative approach, interested in big life-stories, as well as small stories of everyday interaction. Over the course of two years, five child participants aged between eight and 12 years constructed narrative material through participatory action research methodologies, including the mapping of time-lines and their lived environments, and photovoice. Child participants and their families were selected from the client-base of a non-governmental organisation, Isibindi (Alice). Narratives were analysed as case studies to tell detailed stories of children’s lives, and to comment on issues associated with domestic mobility, socio-economic status, gender, education, HIV/AIDS and social protection. The study found that blanket definitions of poverty and domestic mobility conceal important variations in levels of poverty and individual experiences of mobility. While children are excluded from processes of decision-making about their mobility, they perform their agency by contributing to household survival and ensuring the continuation of mutually beneficial attachment relationships. This research argues that interventions which act on various systemic levels (macro, meso and exo) add support and protection for vulnerable children. This research also argues for psychological “scaffolding” of potentially traumatic or precarious processes, such as domestic mobility and deaths in families, through caregivers preparing and consulting with children before events happen.
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  • Date Issued: 2017

A narrative-discursive analysis of abortion decision-making in Zimbabwe

  • Authors: Chiweshe, Malvern Tatenda
  • Date: 2016
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/496 , vital:19964
  • Description: Most research on abortion decision-making has looked at the factors or influences that are seen to affect abortion decision-making and thus take a health determinants approach. However, this approach is rarely able to account for the complex, multi-faceted nature of abortion decision-making, and it is often not located within a framework that can unpick the complex array of power relations that underpins the process of abortion decision-making. Research on abortion decision-making has rarely examined how women who undergo a termination of pregnancy (TOP) construct micro-narratives of the decision to terminate the pregnancy and also how these women are positioned by the service providers who interact with them. Using a Foucauldian postcolonial feminist approach and narrative-discursive analysis, this study explores abortion decision-making narratives in a Zimbabwean context where abortion laws are restrictive. In this study I elicited the narratives of women who had undergone an abortion about how they came to make the decision and proceeded to terminate the pregnancy. I highlight the discourses employed in constructing these narratives and how women position themselves in these narratives and discourses. These are then compared to the subject positions enabled in health service providers’ narratives on the same topic. These narratives are then linked to the social discourses and power relations that work to enable or constrain reproductive justice. The data were collected from three sites in Harare, Zimbabwe. The three sites were Harare Hospital, Epworth and Mufakose. An adapted version of Wengraf’s (2001) narrative interview was used to elicit narratives from 18 women who had terminated pregnancies (six at each site). Semi-structured interviews were conducted with six service providers (two nurses at Harare Hospital, two village health workers in Epworth and two nurses in Mufakose). All the service providers interviewed have experience working with women who have terminated pregnancies. In narrating their stories about their abortions, the women employed discursive resources around shame, stigma, religion, health and culture. These discursive resources were drawn upon in the construction of the women’s micro-narratives. The women spoke in a socially sanctioned manner where stories were enabled and constrained by particular religious, cultural and gendered discursive resources. In these stories, cultural constructions, gendered understandings of motherhood and femininity constrained reproductive justice for women who have terminated pregnancies. Comparisons of the way women positioned themselves and how they were positioned by health service providers point to the existence of social discourses and power relations that work to constrain reproductive justice. While the women saw themselves as having ‘unsupportable pregnancies’, the service providers positioned them as being evil, selfish and irresponsible. The negative positions deployed by the service providers point to the vilification and blaming of women who have undergone a termination of pregnancy. In these positions, the woman is at fault and there is silence on the role of men in abortion decision-making. In the women’s narratives and the health service providers positioning of the women a ‘reproductive rights’ discourse was absent. This was significant as much of the activism around abortion has centred on the woman’s rights to her body. Where rights were mentioned, it was in reference to foetal rights (using cultural, moralistic religious understandings of abortion as killing). The missing ‘reproductive rights’ discourse points to a need to move from a reproductive rights framework to a reproductive justice framework that can be applied through local understandings of hunhu/ubuntu. By doing this, abortion is not seen as a ‘choice’ that a woman makes but rather as involving broader social and environmental circumstances that make a pregnancy ‘unsupportable’.
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  • Date Issued: 2016

A national strategy towards cultivating a cybersecurity culture in South Africa

  • Authors: Gcaza, Noluxolo
  • Date: 2017
  • Subjects: Computer networks -- Security measures , Cyberspace -- Security measures Computer security -- South Africa Subculture -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/13735 , vital:27303
  • Description: In modern society, cyberspace is interwoven into the daily lives of many. Cyberspace is increasingly redefining how people communicate as well as gain access to and share information. Technology has transformed the way the business world operates by introducing new ways of trading goods and services whilst bolstering traditional business methods. It has also altered the way nations govern. Thus individuals, organisations and nations are relying on this technology to perform significant functions. Alongside the positive innovations afforded by cyberspace, however, those who use it are exposed to a variety of risks. Cyberspace is beset by criminal activities such as cybercrime, fraud, identity theft to name but a few. Nonetheless, the negative impact of these cyber threats does not outweigh the advantages of cyberspace. In light of such threats, there is a call for all entities that reap the benefits of online services to institute cybersecurity. As such, cybersecurity is a necessity for individuals, organisations and nations alike. In practice, cybersecurity focuses on preventing and mitigating certain security risks that might compromise the security of relevant assets. For a long time, technology-centred measures have been deemed the most significant solution for mitigating such risks. However, after a legacy of unsuccessful technological efforts, it became clear that such solutions in isolation are insufficient to mitigate all cyber-related risks. This is mainly due to the role that humans play in the security process, that is, the human factor. In isolation, technology-centred measures tend to fail to counter the human factor because of the perception among many users that security measures are an obstacle and consequently a waste of time. This user perception can be credited to the perceived difficulty of the security measure, as well as apparent mistrust and misinterpretation of the measure. Hence, cybersecurity necessitates the development of a solution that encourages acceptable user behaviour in the reality of cyberspace. The cultivation of a cybersecurity culture is thus regarded as the best approach for addressing the human factors that weaken the cybersecurity chain. While the role of culture in pursuing cybersecurity is well appreciated, research focusing on defining and measuring cybersecurity culture is still in its infancy. Furthermore, studies have shown that there are no widely accepted key concepts that delimit a cybersecurity culture. However, the notion that such a culture is not well-delineated has not prevented national governments from pursuing a culture in which all citizens behave in a way that promotes cybersecurity. As a result, many countries now offer national cybersecurity campaigns to foster a culture of cybersecurity at a national level. South Africa is among the nations that have identified cultivating a culture of cybersecurity as a strategic priority. However, there is an apparent lack of a practical plan to cultivate such a cybersecurity culture in South Africa. Thus, this study sought firstly to confirm from the existing body of knowledge that cybersecurity culture is indeed ill-defined and, secondly, to delineate what constitutes a national cybersecurity culture. Finally, and primarily, it sought to devise a national strategy that would assist SA in fulfilling its objective of cultivating a culture of cybersecurity on a national level.
  • Full Text:
  • Date Issued: 2017

A networking approach to sharing music studio resources

  • Authors: Foss, Richard John
  • Date: 1996
  • Subjects: MIDI (Standard) Computer sound processing Sound -- Recording and reproducing -- Digital techniques
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4659 , http://hdl.handle.net/10962/d1006660
  • Description: This thesis investigates the extent to which networking technology can be used to provide remote workstation access to a pool of shared music studio resources. A pilot system is described in which MIDI messages, studio control data, and audio signals flow between the workstations and a studio server. A booking and timing facility avoids contention and allows for accurate reports of studio usage. The operation of the system has been evaluated in terms of its ability to satislY three fundamental goals, namely the remote, shared and centralized access to studio resources. Three essential network configurations have been identified, incorporating a mix of star and bus topologies, and their relative potential for satisfYing the fundamental goals has been highlighted.
  • Full Text:
  • Date Issued: 1996

A neural network based ionospheric model for the bottomside electron density profile over Grahamstown, South Africa

  • Authors: McKinnell, L A
  • Date: 2003
  • Subjects: Neural networks (Computer science) Ionospheric electron density -- South Africa -- Grahamstown
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5477 , http://hdl.handle.net/10962/d1005262
  • Description: This thesis describes the development and application of a neural network based ionospheric model for the bottomside electron density profile over Grahamstown, South Africa. All available ionospheric data from the archives of the Grahamstown (33.32ºS, 26.50ºE) ionospheric station were used for training neural networks (NNs) to predict the parameters required to produce the final profile. Inputs to the model, called the LAM model, are day number, hour, and measures of solar and magnetic activity. The output is a mathematical description of the bottomside electron density profile for that particular input set. The two main ionospheric layers, the E and F layers, are predicted separately and then combined at the final stage. For each layer, NNs have been trained to predict the individual ionospheric characteristics and coefficients that were required to describe the layer profile. NNs were also applied to the task of determining the hours between which an E layer is measurable by a groundbased ionosonde and the probability of the existence of an F1 layer. The F1 probability NN is innovative in that it provides information on the existence of the F1 layer as well as the probability of that layer being in a L-condition state - the state where an F1 layer is present on an ionogram but it is not possible to record any F1 parameters. In the event of an L-condition state being predicted as probable, an L algorithm has been designed to alter the shape of the profile to reflect this state. A smoothing algorithm has been implemented to remove discontinuities at the F1-F2 boundary and ensure that the profile represents realistic ionospheric behaviour in the F1 region. Tests show that the LAM model is more successful at predicting Grahamstown electron density profiles for a particular set of inputs than the International Reference Ionosphere (IRI). It is anticipated that the LAM model will be used as a tool in the pin-pointing of hostile HF transmitters, known as single-site location.
  • Full Text:
  • Date Issued: 2003

A new approach to the Zulu land tenure system: an historical anthropological explanation of the development of an informal settlement

  • Authors: Fourie, Clarissa Dorothy
  • Date: 1993
  • Subjects: Land tenure -- South Africa -- Kwazulu Kwazulu (South Africa) -- Economic conditions Zulu (African people) -- Social conditions Kwazulu (South Africa) -- Social conditions
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:2098 , http://hdl.handle.net/10962/d1002661
  • Description: Mgaga, an informal settlement in KwaZulu, south of Durban, on Cele-Zulu polity land, had an indigenous, albeit urban, system of Zulu land tenure in 1980. Mgaga's transformation, from an area with scattered homesteads in 1959 to an informal settlement, was linked to local and external factors. The external factors were, regional industrialisation, urbanisation and apartheid policies which involved, the division of South Africa into ethnically based 'homelands'; controlled Black access to 'White' cities; an urban management system for 'homeland' townships, like Umlazi township which abutted Mgaga. Umlazi's development and urban management system involved, the resettlement of members of the polity; the removal of their office bearers from their posts; and the phased building of the township; which caused cumulative effects in Mgaga. I link these external factors to the behaviour of Mgaga's residents, who transformed the area's land tenure system, by using Comaroff's dialectical model (1982), where the internal dialectic interacts with external factors to shape behaviour at the local level. I analyze the Zulu ethnography to show that the internal dialectic in Zulu social organisation, and in Mgaga, is centred around fission and integration; and that the integrating hierarchy associated with Zulu social organisation and the Zulu land tenure system is composed of groups with opposed interests in the same land. Within this hierarchy entrepreneurship and coalition formation influence the transfer of land rights. Also, rather than rules determining the transfer of land in the land tenure system, processes associated with the interaction of external factors with the internal dialectic, within terms of the cultural repertoire associated with the system, shape local behaviour; and the system's rules are manipulated within this cultural repertoire by individuals striving for gain. This results in different manifestations of the internal dialectic in the Zulu land tenure system, i.e. a range of variations in the Zulu land tenure system, including different local level kinship groups; a variety of terminology and rights held by office bearers; and communal and individualised land rights. The external factor of urbanisation interacted with the internal dialectic in Mgaga, manifested in terms of an ongoing izigodi (wards) dispute -including its boundaries, to shape residents' behaviour, so that some introduced an informal settlement and others resisted its geographical spread. This informal settlement development, where eventually purely residential land rights were transferred for cash to strangers by strangers, with no role for polity officials, was an urban variation of the Zulu land tenure system, because of the continued existence of the internal dialectic in Zulu social organisation in the local system, with the integration side being expressed by the community overrights. Characteristics found in Mgaga, such as kinship diminution; the individualisation and sale of land rights; and the ongoing influence of polities; are found elsewhere in Africa where informal settlements have developed on indigenous land tenure systems. Therefore the transformation of Mgaga's land tenure system to urban forms is not an isolated phenomenon, and my dialectical ransactional approach may have an applicability beyond the context of the Zulu land tenure system.
  • Full Text:
  • Date Issued: 1993

A new model of the IO-Controlled Jovian decametric radiation

  • Authors: Goertz, Christoph K
  • Date: 1972
  • Subjects: Jupiter (Planet) Radiation Magnetosphere Ionosphere
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5521 , http://hdl.handle.net/10962/d1012043
  • Description: Jupiter, the largest planet in the solar system, is not only an emitter of thermal radiation like any other planet. Jupiter also emits relatively high-intensity non-thermal radiation in two bands, the decimetre wavelength range and the decametre wavelength range (5 MHz< f < 40 MHz). The decimetric radiation is believed to be due to synchrotron radiation of electrons trapped in a kind of Jovian "Van Allen belt". This thesis deals almost exclusively with the decametric radiation. Although the decametric radiation has been observed for 15 years since its discovery by Burke and Franklin in 1955, there is no generally accepted theoretical model of its generation to be found in the literature as yet. This is not surprising, as there are many complex and confusing aspects of the radiation. And since our knowledge of the Jovian ionosphere, magnetosphere and magnetic field is very limited indeed, every theoretical model must be based on some more or less well justified assumptions. It is, however, possible to draw some conclusions from the observed properties of the decimetric and decametric radiation. The radiation in both bands is polarized. It has been shown that at least part of the polarization is an intrinsic property of the radiation source at Jupiter, This indicates the existence of a Jovian magnetic field. The magnitude and shape of the magnetic field, however, is open to discussion, although a dipole field does seem to be a good approximation at least for large distances from Jupiter. Intro. p. 1-2.
  • Full Text:
  • Date Issued: 1972

A new synthetic approach for preparation of Efavirenz

  • Authors: Chada, Sravanthi
  • Date: 2017
  • Subjects: Antiretroviral agents , Asymmetric synthesis , Enzyme inhibitors , HIV (Viruses) -- Enzymes
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/15512 , vital:28265
  • Description: Efavirenz, a drug that is still inaccessible to millions of people worldwide, is potent non nucleoside reverse transcriptase inhibitor (NNRTI), is one of the preferred agents used in combination therapy for first-line treatment of the human immunodeficiency virus (HIV). NNRTIs attach to and block an HIV enzyme called reverse transcriptase, by blocking reverse transcriptase; NNRTIs prevent HIV from multiplying and can reduce the amount of HIV in the body. Efavirenz can't cure HIV/AIDS, but taken in combination with other HIV medicines (called an HIV regimen) every day helps people with HIV live longer healthier lives. Efavirenz also reduces the risk of HIV transmission and can be used by children who are suffering from HIV/AIDS. All the above therapeutic uses of efavirenz prompted us to identify the novel and hopefully cost efficient synthetic methodology for the preparation of efavirenz. In this thesis a new synthetic method for asymmetric synthesis of efavirenz is described. This route started from commercially available starting materials and it is first established in traditional batch chemistry and further the parameters transferred to a semi continuous flow protocol for optimization.
  • Full Text:
  • Date Issued: 2017

A novel, improved throughput bioassay for determining the delative speed of antimalarial drug action using fluorescent vitality probes

  • Authors: Laming, Dustin
  • Date: 2020
  • Subjects: Plasmodium falciparum , Malaria -- Treatment -- Africa , Antimalarials , Malaria vaccine
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/139902 , vital:37810
  • Description: Malaria is one of the most prevalent diseases in Africa and Plasmodium falciparum is widely accepted as the most virulent of the malaria parasite species, with a fatality rate of 15 – 20 % of reported cases of infection. While various treatments have been accepted into early stage clinical trials, there has been little progress towards a proven vaccine. Pending a long-term solution, endemic countries rely heavily on the development of innovative drugs that are not only efficacious but are also quick acting. Traditional methods of evaluating antimalarial killing speeds via morphological assessments are inherently flawed by tedious, subjective interpretations of the heterogenous parasite morphology encountered in routine parasite culture conditions. This has led to the introduction of alternative assay formats to determine how rapidly compounds act on parasites in vitro: a parasite reduction ratio (PRR) assay that measures the recovery of parasite cultures from drug exposure; determining the shift in IC50 values of compounds when dose-response assays are carried out for different time periods; a bioluminescence relative rate of kill (BRRoK) assay that compares the extent to which compounds reduce firefly luciferase activity in transgenic parasites. Recent whole cell in vitro screening efforts have resulted in the generation of chemically diverse compound libraries such as the Medicines for Malaria Venture’s Pathogen Box, which houses 125 novel compounds with in vitro antiplasmodial activity. Assessing the relative killing speeds of these compounds would aid prioritizing fast-acting compounds that can be exploited as starting points for further development. This study aimed to develop a bioassay using the calcein-acetoxymethyl and propidium iodide fluorescent vitality probes, which would allow the relative speed of drug action on Plasmodium falciparum malaria parasites to be assessed and ranked in relation to each other using a quantitative, improved throughput approach. Initially applied to human (HeLa) cells, the assay was used to compare the relative speeds of action of 3 potential anti-cancer compounds by fluorescence microscopy. Subsequently adapted to P. falciparum, the assay was able to rank the relative speeds of action of standard antimalarials by fluorescence microscopy and two flow cytometry formats. Application of a multiwell flow cytometer increased throughput and enabled the assessment of experimental compounds, which included a set of artemisinin analogs and 125 antimalarial compounds in the MMV Pathogen Box. The latter culminated in the identification of five rapidly parasiticidal compounds in relation to the other compounds in the library, which may act as benchmark references for future studies and form the basis of the next generation of fast acting antimalarials that could be used to combat modern, resistant malaria.
  • Full Text:
  • Date Issued: 2020

A pastoral theological examination of inner healing

A personality-based surveillance model for Facebook apps

  • Authors: Van der Schyff, Karl Izak
  • Date: 2020
  • Subjects: Facebook (Electronic resource) , Electronic surveillance -- Psychological aspects , Online social networks -- Psychological aspects , Social media -- Psychological aspects , Personality
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/145534 , vital:38447
  • Description: The surveillance of data through the use of Facebook Apps is an ongoing and persistent problem that impacts millions of users. Nonetheless, limited research has been conducted investigating to what extent a Facebook user’s personality influences their awareness of such surveillance practices. Thus, to understand this situation better, the current study inductively developed four propositions from secondary data sources as part of a detailed content analysis. Spanning three search and analysis phases the content analysis led to the development of the research model. Guided by the propositions and research questions, a questionnaire was developed based on the relevant constructs prescribed by the Theory of Planned Behaviour. This questionnaire was used, and a total of 651 responses were collected from Facebook users over the age of 18 years old and residing in the United States of America. Primary data took place at both a univariate and multivariate level with a specific focus on the development of a structural model. Interpretation of the structural model revealed that out of all the Big Five personality traits, Conscientiousness exhibited the strongest relationship with information security awareness followed by Openness to Experience and Neuroticism, respectively. The results further indicated that the model constructs based on attitude, social norms and awareness significantly influenced the intended use of Facebook Apps. The study also contributes by indicating which personality traits are most vulnerable to Facebook App surveillance. For example, it was found that individuals high in Conscientiousness are the least vulnerable with individuals high in Extraversion being the most vulnerable. Since the results indicate that not all the personality traits are significantly related to the model constructs, additional factors may contribute to App surveillance in this context. Concerning this, factors such as user apathy, information privacy, privacy concerns, control and Facebook dependency are discussed as a means to argue why this might be the case.
  • Full Text:
  • Date Issued: 2020

A petrological and mineralogical study of peridotite and eclogite xenoliths from certain kimberlite pipes

  • Authors: Whitfield, Gavin
  • Date: 1972
  • Subjects: Petrology Peridotite Mineralogy Kimberlite Igneous rocks -- Inclusions Eclogite
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5044 , http://hdl.handle.net/10962/d1007690
  • Description: Kimberlite, an ultrabasic diamond-bearing hypabyssal rock-type which has its origin in the Earth's upper mantle, characteristically contains rare, well-rounded xenoliths of peridotite and eclogite. These xenoliths, which undoubtedly originate from some considerable depth below the Earth's surface, possibly represent samples of upper mantle material. They have received much attention from earth scientists and numerous theories as to their origin have been proposed. Forty-two selected peridotite xenoliths from the Bultfontein, Wesselton, Dutoitspan and Roberts Victor kimberlite pipes of the Kimberley area, South Africa, and 24 eclogite xenoliths from the Roberts Victor pipe have been examined in detail using a variety of petrological and mineralogical techniques. The petrologic research comprises conventional petrographic studies, the determination of accurate modal compositions and the presentation of 22 new whole-rock chemical analyses, nine of which are of garnet peridotite, four of spinel peridotite and nine of eclogite, one being a diamondiferous specimen. Detailed mineralogical studies of the constituent minerals of the xenoliths comprises descriptive mineralogy, in most cases an estimation of the compositions of these minerals from the measurement of physical properties, X-ray powder diffraction data and the presentation of 21 new chemical analyses of pure mineral separates. This includes five analyses of clivine, five of orthopyroxene, eight of garnet, one of chrome diopside and two of omphacite. The results of the investigation have shown that the peridotites consist essentially of forsterite and enstatite with minor or trace amounts of one or more of pyrope-rich garnet, chrome diopside, chrome spinel, phlogopite and rarely graphite, and often exhibit features consistent with plastic movement and tectonic deformation. The peridotites are believed to be derived from an ultrabasic upper mantle, which is both chemioally and physically zoned. The eclogite xenoliths, which are composed mainly of pyrope-almandine garnet and omphacitic clinopyroxene and occasionally contain kyanite, corundum and diamond, are not samples of a primary eclogitic upper mantle nor the products of an eclogite fractionation related to kimberlite genesis. Chemically they are not typical of extrusive basalts and probably either represent pockets of partially fractionated basic magma trapped at mantle-level in an eclogite-stable environment or samples of high-grade crustal metamorphic eclogite accidentally incorporated into the Roberts Victor kimberlite.
  • Full Text:
  • Date Issued: 1972
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