Sediment connectivity in the upper Thina Catchment, Eastern Cape, South Africa
- Van der Waal, Benjamin Cornelis Wentsel
- Authors: Van der Waal, Benjamin Cornelis Wentsel
- Date: 2015
- Subjects: Soil erosion -- South Africa -- Eastern Cape , Sedimentation and deposition -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Arroyos -- South Africa -- Eastern Cape , Sediment transport -- South Africa -- Eastern Cape , Soil conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4892 , http://hdl.handle.net/10962/d1019754
- Description: [Portion of abstract]: Sediment dynamics are influenced by transformed landscape connectivity in catchments worldwide. The upper Thina catchment, an important high rainfall resource in the northern Eastern Cape, South Africa, is an example of where ongoing subsistence farming on communal land has led to overgrazing and trampling that has initiated large erosive features (e.g. gullies) and river incision. The formation of gullies led to increased hillslope-channel connectivity and the resultant river incision decreased the channel-valley fill connectivity. These two changes in connectivity led to increased sediment export from the catchment that has various down-stream ecological and socio-economic impacts. This study investigates how the change in hillslope-channel and channel-valley fill connectivity has altered the sediment dynamics in the Vuvu catchment, a headwater tributary of the Thina River. A combination of methods were used to assess the changes in hillslope-channel and channel-valley fill connectivity. High resolution aerial images were used to map source features, such as fields, gullies, sheet erosion, landslides, roads and livestock tracks. Topographic and geological characteristics of the source features were extracted using a Geographic Information System. Furthermore, hillslope-channel pathways, such as the natural drainage network, continuous gullies, discontinuous gullies, roads and livestock tracks were mapped and analysed in terms of topographic and geological characteristics. Historic aerial images were assessed to calculate the date the larger gullies began forming. Recent aerial photos and cross sectional surveys of the valley fill were combined to map the various sediment sinks. Particle size and organic content were analysed for flood bench cores and terrace samples. The chronology of the flood benches was determined using unsupported Pb-210 and Cs-137 dating, and determined for the terraces using Optically Stimulated Luminescence dating. Quantitative and qualitative sediment tracing approaches, using mineral magnetic properties, were used to trace the origin of suspended sediment (collected during flood events), sediment stored in the flood benches and sediment stored in the terraces. Hydrological monitoring was used to assess the potential to store sediment on flood benches along the valley fill through flood bench inundation frequency. Hydrological and hydraulic modelling extended the measured inundation frequencies to a 73 year period and other cross sections along the valley fill. Furthermore, a future scenario of an increased vegetation cover and reduced hillslope-channel connectivity was assessed in terms of channel-valley fill inundation frequency.
- Full Text:
- Date Issued: 2015
- Authors: Van der Waal, Benjamin Cornelis Wentsel
- Date: 2015
- Subjects: Soil erosion -- South Africa -- Eastern Cape , Sedimentation and deposition -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Arroyos -- South Africa -- Eastern Cape , Sediment transport -- South Africa -- Eastern Cape , Soil conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4892 , http://hdl.handle.net/10962/d1019754
- Description: [Portion of abstract]: Sediment dynamics are influenced by transformed landscape connectivity in catchments worldwide. The upper Thina catchment, an important high rainfall resource in the northern Eastern Cape, South Africa, is an example of where ongoing subsistence farming on communal land has led to overgrazing and trampling that has initiated large erosive features (e.g. gullies) and river incision. The formation of gullies led to increased hillslope-channel connectivity and the resultant river incision decreased the channel-valley fill connectivity. These two changes in connectivity led to increased sediment export from the catchment that has various down-stream ecological and socio-economic impacts. This study investigates how the change in hillslope-channel and channel-valley fill connectivity has altered the sediment dynamics in the Vuvu catchment, a headwater tributary of the Thina River. A combination of methods were used to assess the changes in hillslope-channel and channel-valley fill connectivity. High resolution aerial images were used to map source features, such as fields, gullies, sheet erosion, landslides, roads and livestock tracks. Topographic and geological characteristics of the source features were extracted using a Geographic Information System. Furthermore, hillslope-channel pathways, such as the natural drainage network, continuous gullies, discontinuous gullies, roads and livestock tracks were mapped and analysed in terms of topographic and geological characteristics. Historic aerial images were assessed to calculate the date the larger gullies began forming. Recent aerial photos and cross sectional surveys of the valley fill were combined to map the various sediment sinks. Particle size and organic content were analysed for flood bench cores and terrace samples. The chronology of the flood benches was determined using unsupported Pb-210 and Cs-137 dating, and determined for the terraces using Optically Stimulated Luminescence dating. Quantitative and qualitative sediment tracing approaches, using mineral magnetic properties, were used to trace the origin of suspended sediment (collected during flood events), sediment stored in the flood benches and sediment stored in the terraces. Hydrological monitoring was used to assess the potential to store sediment on flood benches along the valley fill through flood bench inundation frequency. Hydrological and hydraulic modelling extended the measured inundation frequencies to a 73 year period and other cross sections along the valley fill. Furthermore, a future scenario of an increased vegetation cover and reduced hillslope-channel connectivity was assessed in terms of channel-valley fill inundation frequency.
- Full Text:
- Date Issued: 2015
Co-mapping the maze: a complex systems view of human trafficking in the Eastern Cape
- Authors: Van der Westhuizen, Amanda
- Date: 2015
- Subjects: Human trafficking -- South Africa -- Eastern Cape Forced labor -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23305 , vital:30523
- Description: Researchers have described human trafficking as a complex, multi-layered crime. South Africa, including the Eastern Cape Province, is a source, transit, and destination country for trafficked people. However, a dearth of research on human trafficking exists in the province. Furthermore, traditional, modernist research using reductionist methods to investigate complex phenomena has proven unable to capture the complex interrelationships between the myriad of interrelated elements inherent in complex phenomena. In this qualitative study, I explore and describe the human trafficking system in the Eastern Cape via participants’ perspectives through a complex systems approach that consists of two complementary theories, namely Bronfenbrenner’s bioecological theory of human development and complexity theory. The participants, who were knowledgeable about human trafficking in the province, were obtained through purposive and snowball sampling. Data collection took place through open-ended interviews with individual participants. I analysed the data according to Miles and Huberman’s data analysis process and Braun and Clarke’s thematic data analysis process. The findings demonstrate that the complex systems approach successfully facilitated the mapping and conceptualisation of an in-depth, multi-level picture of the complex interrelationships within and between multiple system components in the human trafficking system and its environment in relation to the Eastern Cape Province. Participants’ perspectives revealed two main themes, namely, the prominence of the nonlinear interactions between traffickers and trafficked persons in the holistic human trafficking system and the major obstacle regarding the lack of witness credibility for human trafficking prosecutions to be successful. Utilising complex systems theory to conduct further human trafficking research could assist counter-trafficking stakeholders with an alternative approach to generating effective planning and executing counter human trafficking strategies in a rapidly changing and increasing complex interconnected world.
- Full Text:
- Date Issued: 2015
- Authors: Van der Westhuizen, Amanda
- Date: 2015
- Subjects: Human trafficking -- South Africa -- Eastern Cape Forced labor -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23305 , vital:30523
- Description: Researchers have described human trafficking as a complex, multi-layered crime. South Africa, including the Eastern Cape Province, is a source, transit, and destination country for trafficked people. However, a dearth of research on human trafficking exists in the province. Furthermore, traditional, modernist research using reductionist methods to investigate complex phenomena has proven unable to capture the complex interrelationships between the myriad of interrelated elements inherent in complex phenomena. In this qualitative study, I explore and describe the human trafficking system in the Eastern Cape via participants’ perspectives through a complex systems approach that consists of two complementary theories, namely Bronfenbrenner’s bioecological theory of human development and complexity theory. The participants, who were knowledgeable about human trafficking in the province, were obtained through purposive and snowball sampling. Data collection took place through open-ended interviews with individual participants. I analysed the data according to Miles and Huberman’s data analysis process and Braun and Clarke’s thematic data analysis process. The findings demonstrate that the complex systems approach successfully facilitated the mapping and conceptualisation of an in-depth, multi-level picture of the complex interrelationships within and between multiple system components in the human trafficking system and its environment in relation to the Eastern Cape Province. Participants’ perspectives revealed two main themes, namely, the prominence of the nonlinear interactions between traffickers and trafficked persons in the holistic human trafficking system and the major obstacle regarding the lack of witness credibility for human trafficking prosecutions to be successful. Utilising complex systems theory to conduct further human trafficking research could assist counter-trafficking stakeholders with an alternative approach to generating effective planning and executing counter human trafficking strategies in a rapidly changing and increasing complex interconnected world.
- Full Text:
- Date Issued: 2015
Countertrade as a development tool: a comparative analytical approach
- Authors: Van Dyk, Johannes Jacobus
- Date: 2015
- Subjects: Countertrade , Countertrade -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/5054 , vital:20795
- Description: This study explores the consequences of defence countertrade arrangements for national development based on the South African experience in comparative perspective. Although defence countertrade has been controversial in many contexts, it is concluded that it may play a positive developmental role. This is premised on the central role governments can play in ensuring that countertrade's role in national economic development – global pressures and neo-liberalism notwithstanding – remains an important tool through which active industrial policy may be pursued. This can include developing and maintaining a defence industrial base (DIB) in those countries that have such capabilities. Countertrade occurs under two kinds of market conditions. The one is where there is a natural need for trading but it is constrained in some way, for example, by an absence of currency or an oversupply. Under these conditions countries can resort to bartering, which involves a commodity for commodity exchange and no money. The second market condition is one where countertrade is purposefully structured to secure reciprocal benefits as a condition of a commercial sales transaction - defence or civil in nature. This is referred to as leveraged procurement and manifests primarily as defence offsets involving the defence industrial base, which is the concern of this study. Around 40 per cent of countries, including South Africa, use various purposely structured government procurement programmes when procuring goods and services abroad. These programmes apply the principle of reciprocity through the use of internationally accepted countertrade practices that manifest in many diverse ways. Although „countertrade‘ is the collective term, it is regularly referred to as „offsets‘. Procurement leverage is used to secure some reciprocal benefit from the foreign seller (benefits sought vary from country to country). Countertrade-related practices occur widely despite the fact that the World Trade Organisation's (WTO) Agreement on Government Procurement (GPA6) rules out the use of offsets. Their use is viewed as a discriminatory procurement practice that interferes with free trade. However, the WTO allows for exceptions in the case of developing countries and also for national security and public health contracts. It is important to note that countertrade (and offset) practices, valued in billions of US Dollars, are applicable mostly to defence contracts, although becoming increasingly relevant in non-defence (i.e. civil) government procurements. This research systematically interrogated and investigated issues surrounding the origins and subsequent popular and increased use of countertrade since the 1980s. The purported negative impact of defence-related offsets on the defence industrial base (i.e. the loss or gain of jobs, technology and market share) of both the exporting and receiving countries is of particular concern to the US government and the European Union (EU). My exploratory mixed method research, together with practitioner (insider) and reflexive research approaches, culminated in a primarily descriptive, qualitative, analytical narrative. The research is further founded on structured survey questionnaires. These specific research approaches are known to be subjective and biased and I thus needed to take extra care to prevent emotive subjectivities, primarily through triangulating my findings against a variety of other views and arguments pertaining to the research question. This was done to provide for a holistic overview, and in consideration of the case study, in particular. It must be noted that South Africa has two sets of industrial participation policies and practices. One is Defence Industrial Participation (DIP) managed exclusively by Armscor, South Africa's acquisition agency, which favours pursuing defence industry development objectives. The other is the National Industrial Participation Programme (NIPP), managed independently by the Department of Trade and Industry (DTI). The NIPP is primarily focused on the civil industry with a bias towards manufacturing, investments and exports. The DIP is the focus of the case study element of this research. Since its inception in 1968, Armscor has been tasked with establishing a DIB. Until the late 1980s, this DIB made huge strides in developing unique defence equipment to cater for the harsh Southern African environment and its military operational conditions. The DIB's development was enhanced further by the various UN embargoes imposed on the former South African apartheid government. Owing to these embargoes, Armscor dealt with all its defence imports (and exports) in a clandestine manner. Armscor was the only government entity that applied countertrade from around 1988 until 1996 when the DTI introduced NIPP. During the latter part of 1996, Armscor redrafted its countertrade policy with the new DIP policy approved in early 1997. This policy was applied during the biggest arms transaction in South Africa‟s history, namely, the Strategic Defence Package (SDP). A DIP commitment of circa R15 billion resulted from the equipment bought under the SDP. This study investigated how the DIP manifested in practice from 2000 to 2012 within the DIB that involved numerous South African Defence Industry (SADI) entities. The study considered the DIB, its growth and decline, and to what extent the DIP assisted it to retain its capabilities and capacities, including the retention of jobs. Hence, parts of the case study cover issues related to the South African military complex and the SDP‟s selection process. Subsequent investigations into alleged acts of misconduct and maladministration in the selection process, fraud and corruption are also covered, although not in detail, since this matter is sub judice the outcome of the 2011 presidential appointed Arms Procurement Commission (APC) of inquiry that is anticipating completing its investigations in 2015. Although there are many derivative views on the actual defence equipment needs of the South African National Defence Force (SANDF), the study did not endeavour to analyse these views in depth as they are adequately covered in the 1996 Defence Review. Similarly, there are views expressed that South Africa paid much more for its equipment compared with similar types of equipment bought by other countries. A cost comparative analysis was not performed as the exact configuration of each type of equipment can differ substantially due to the unique operational needs of the various defence forces – the exact configuration of such equipment is not in the public domain, since it is a sovereign security concern. Despite many opposing views, it is concluded that DIP (also referred to as defence offsets) has worked for South Africa: in many ways the South African DIP practice compares favourably with internationally accepted best practices. The research‟s postulation that countertrade can be used as a possible development mechanism is therefore supported by the findings of this study that showed that DIP had a positive retention impact on the DIB, and jobs, and made a positive contribution to Gross National Product (GNP7). The study found that the 1997 DIP policy needed to be much better aligned with the broader strategic national industrial development aims and objectives, including better corroboration with the NIPP. In this respect critical inferences are made that the DIP policy primarily focused on the SADI and its capabilities, without considering its wider application in a broader industrial sense. However, in the context of the Armscor legal mandate (i.t.o. Act 57 of 1968) ensuring the establishment of a DIB in South Africa, the DIP policy was clear in its intent to specifically further the interests of only the SADI. However, the 2014 Defence Review recommends that the DIP policy should be much more focused and even prescriptive when considering specific strategic defence needs. Although DIP policy directives contain requirements for establishing strategic local capabilities and capacities that could adequately cater for logistic support, repair and maintenance of foreign produced defence equipment, this aspect was not well contracted in the 1999 SDP. There is also general consensus that foreign obligors should in future not be allowed the freedoms of choice evident in the SDP‟s DIP process, which resulted in numerous smaller companies not benefitting as was generally anticipated. Future defence contracts should not be signed without an appropriate DIP business plan. Hence, all indications are that the DIP regime in South Africa is set to become much more stringent in its application and subsequent discharge administration.
- Full Text:
- Date Issued: 2015
- Authors: Van Dyk, Johannes Jacobus
- Date: 2015
- Subjects: Countertrade , Countertrade -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/5054 , vital:20795
- Description: This study explores the consequences of defence countertrade arrangements for national development based on the South African experience in comparative perspective. Although defence countertrade has been controversial in many contexts, it is concluded that it may play a positive developmental role. This is premised on the central role governments can play in ensuring that countertrade's role in national economic development – global pressures and neo-liberalism notwithstanding – remains an important tool through which active industrial policy may be pursued. This can include developing and maintaining a defence industrial base (DIB) in those countries that have such capabilities. Countertrade occurs under two kinds of market conditions. The one is where there is a natural need for trading but it is constrained in some way, for example, by an absence of currency or an oversupply. Under these conditions countries can resort to bartering, which involves a commodity for commodity exchange and no money. The second market condition is one where countertrade is purposefully structured to secure reciprocal benefits as a condition of a commercial sales transaction - defence or civil in nature. This is referred to as leveraged procurement and manifests primarily as defence offsets involving the defence industrial base, which is the concern of this study. Around 40 per cent of countries, including South Africa, use various purposely structured government procurement programmes when procuring goods and services abroad. These programmes apply the principle of reciprocity through the use of internationally accepted countertrade practices that manifest in many diverse ways. Although „countertrade‘ is the collective term, it is regularly referred to as „offsets‘. Procurement leverage is used to secure some reciprocal benefit from the foreign seller (benefits sought vary from country to country). Countertrade-related practices occur widely despite the fact that the World Trade Organisation's (WTO) Agreement on Government Procurement (GPA6) rules out the use of offsets. Their use is viewed as a discriminatory procurement practice that interferes with free trade. However, the WTO allows for exceptions in the case of developing countries and also for national security and public health contracts. It is important to note that countertrade (and offset) practices, valued in billions of US Dollars, are applicable mostly to defence contracts, although becoming increasingly relevant in non-defence (i.e. civil) government procurements. This research systematically interrogated and investigated issues surrounding the origins and subsequent popular and increased use of countertrade since the 1980s. The purported negative impact of defence-related offsets on the defence industrial base (i.e. the loss or gain of jobs, technology and market share) of both the exporting and receiving countries is of particular concern to the US government and the European Union (EU). My exploratory mixed method research, together with practitioner (insider) and reflexive research approaches, culminated in a primarily descriptive, qualitative, analytical narrative. The research is further founded on structured survey questionnaires. These specific research approaches are known to be subjective and biased and I thus needed to take extra care to prevent emotive subjectivities, primarily through triangulating my findings against a variety of other views and arguments pertaining to the research question. This was done to provide for a holistic overview, and in consideration of the case study, in particular. It must be noted that South Africa has two sets of industrial participation policies and practices. One is Defence Industrial Participation (DIP) managed exclusively by Armscor, South Africa's acquisition agency, which favours pursuing defence industry development objectives. The other is the National Industrial Participation Programme (NIPP), managed independently by the Department of Trade and Industry (DTI). The NIPP is primarily focused on the civil industry with a bias towards manufacturing, investments and exports. The DIP is the focus of the case study element of this research. Since its inception in 1968, Armscor has been tasked with establishing a DIB. Until the late 1980s, this DIB made huge strides in developing unique defence equipment to cater for the harsh Southern African environment and its military operational conditions. The DIB's development was enhanced further by the various UN embargoes imposed on the former South African apartheid government. Owing to these embargoes, Armscor dealt with all its defence imports (and exports) in a clandestine manner. Armscor was the only government entity that applied countertrade from around 1988 until 1996 when the DTI introduced NIPP. During the latter part of 1996, Armscor redrafted its countertrade policy with the new DIP policy approved in early 1997. This policy was applied during the biggest arms transaction in South Africa‟s history, namely, the Strategic Defence Package (SDP). A DIP commitment of circa R15 billion resulted from the equipment bought under the SDP. This study investigated how the DIP manifested in practice from 2000 to 2012 within the DIB that involved numerous South African Defence Industry (SADI) entities. The study considered the DIB, its growth and decline, and to what extent the DIP assisted it to retain its capabilities and capacities, including the retention of jobs. Hence, parts of the case study cover issues related to the South African military complex and the SDP‟s selection process. Subsequent investigations into alleged acts of misconduct and maladministration in the selection process, fraud and corruption are also covered, although not in detail, since this matter is sub judice the outcome of the 2011 presidential appointed Arms Procurement Commission (APC) of inquiry that is anticipating completing its investigations in 2015. Although there are many derivative views on the actual defence equipment needs of the South African National Defence Force (SANDF), the study did not endeavour to analyse these views in depth as they are adequately covered in the 1996 Defence Review. Similarly, there are views expressed that South Africa paid much more for its equipment compared with similar types of equipment bought by other countries. A cost comparative analysis was not performed as the exact configuration of each type of equipment can differ substantially due to the unique operational needs of the various defence forces – the exact configuration of such equipment is not in the public domain, since it is a sovereign security concern. Despite many opposing views, it is concluded that DIP (also referred to as defence offsets) has worked for South Africa: in many ways the South African DIP practice compares favourably with internationally accepted best practices. The research‟s postulation that countertrade can be used as a possible development mechanism is therefore supported by the findings of this study that showed that DIP had a positive retention impact on the DIB, and jobs, and made a positive contribution to Gross National Product (GNP7). The study found that the 1997 DIP policy needed to be much better aligned with the broader strategic national industrial development aims and objectives, including better corroboration with the NIPP. In this respect critical inferences are made that the DIP policy primarily focused on the SADI and its capabilities, without considering its wider application in a broader industrial sense. However, in the context of the Armscor legal mandate (i.t.o. Act 57 of 1968) ensuring the establishment of a DIB in South Africa, the DIP policy was clear in its intent to specifically further the interests of only the SADI. However, the 2014 Defence Review recommends that the DIP policy should be much more focused and even prescriptive when considering specific strategic defence needs. Although DIP policy directives contain requirements for establishing strategic local capabilities and capacities that could adequately cater for logistic support, repair and maintenance of foreign produced defence equipment, this aspect was not well contracted in the 1999 SDP. There is also general consensus that foreign obligors should in future not be allowed the freedoms of choice evident in the SDP‟s DIP process, which resulted in numerous smaller companies not benefitting as was generally anticipated. Future defence contracts should not be signed without an appropriate DIP business plan. Hence, all indications are that the DIP regime in South Africa is set to become much more stringent in its application and subsequent discharge administration.
- Full Text:
- Date Issued: 2015
Determining the competency of children with developmental delays to testify in criminal trials
- Authors: Van Niekerk, Hester Aletta
- Date: 2015
- Subjects: Child witnesses -- South Africa , Developmentally disabled children -- South Africa , Children -- Legal status, laws, etc. -- South Africa , Evidence (Law) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3722 , http://hdl.handle.net/10962/d1017878
- Description: In South Africa children are required to testify under oath or admonition. The shortcomings of the competency test are of particular relevance to children with developmental disabilities, since courts are not equipped to adequately assess the competency of these children to give evidence. One component of testimonial competency, namely the understanding of the concepts truth and lies, is overemphasised and is examined with questions that are developmentally inappropriate for child witnesses in general. For children with cognitive disabilities, such questions create barriers for participation in the truth-seeking process. Consequently, convictions have been set aside on appeal owing to procedural irregularities found in the implementation of this test. In the literature review on testimonial competency, attention was given to restrictions that specific developmental disabilities impose on the perceptual, cognitive, communication and moral development of children. Two of four components – narrative ability and moral capacity – were studied in a sample of 184 children in middle childhood. Participants’ ability to give coherent and detailed accounts of events, their understanding of the concepts truth, lies, promises and the oath, and the Lyon and Saywitz oath-taking competency test, were investigated. Quantitative and qualitative methods were used for data analysis. Three groups were identified: those children with very limited, average or full testimonial competency. Their capacities were found to be related to maturation of cognitive functions and level of intellectual functioning. Participants were better able to demonstrate their understanding of truth and falsity by responding to the oathtaking test than giving verbal descriptions of these concepts. Whereas 1 percent of participants had a conceptual understanding of an oath, 15 percent understood the concept of a promise. Syncretism and confabulation compromised the narrative accounts of a substantial number of participants. Syncretism relates to immature narrative ability: correct details are combined in an illogical fashion. Confabulation refers to filling memory gaps with fabricated information. Guidelines on the competency determination of children with developmental disabilities were compiled. It is suggested that the competency examination be replaced by a formal, pre-trial competency assessment. The court should also receive expert evidence on how to facilitate meaningful participation when a child with sufficient testimonial competence is the witness.
- Full Text:
- Date Issued: 2015
- Authors: Van Niekerk, Hester Aletta
- Date: 2015
- Subjects: Child witnesses -- South Africa , Developmentally disabled children -- South Africa , Children -- Legal status, laws, etc. -- South Africa , Evidence (Law) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3722 , http://hdl.handle.net/10962/d1017878
- Description: In South Africa children are required to testify under oath or admonition. The shortcomings of the competency test are of particular relevance to children with developmental disabilities, since courts are not equipped to adequately assess the competency of these children to give evidence. One component of testimonial competency, namely the understanding of the concepts truth and lies, is overemphasised and is examined with questions that are developmentally inappropriate for child witnesses in general. For children with cognitive disabilities, such questions create barriers for participation in the truth-seeking process. Consequently, convictions have been set aside on appeal owing to procedural irregularities found in the implementation of this test. In the literature review on testimonial competency, attention was given to restrictions that specific developmental disabilities impose on the perceptual, cognitive, communication and moral development of children. Two of four components – narrative ability and moral capacity – were studied in a sample of 184 children in middle childhood. Participants’ ability to give coherent and detailed accounts of events, their understanding of the concepts truth, lies, promises and the oath, and the Lyon and Saywitz oath-taking competency test, were investigated. Quantitative and qualitative methods were used for data analysis. Three groups were identified: those children with very limited, average or full testimonial competency. Their capacities were found to be related to maturation of cognitive functions and level of intellectual functioning. Participants were better able to demonstrate their understanding of truth and falsity by responding to the oathtaking test than giving verbal descriptions of these concepts. Whereas 1 percent of participants had a conceptual understanding of an oath, 15 percent understood the concept of a promise. Syncretism and confabulation compromised the narrative accounts of a substantial number of participants. Syncretism relates to immature narrative ability: correct details are combined in an illogical fashion. Confabulation refers to filling memory gaps with fabricated information. Guidelines on the competency determination of children with developmental disabilities were compiled. It is suggested that the competency examination be replaced by a formal, pre-trial competency assessment. The court should also receive expert evidence on how to facilitate meaningful participation when a child with sufficient testimonial competence is the witness.
- Full Text:
- Date Issued: 2015
A critical assessment of responsible tourism practices: a case study of Stormsriver adventures
- Authors: Van Zyl, Shireen Rosemary
- Date: 2015
- Subjects: Sustainable tourism , Tourism -- Management , Economic development
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/4954 , vital:20770
- Description: The research problem was based on the private sector implementation of Responsible Tourism, since 1996, perceived to be slow and challenging (Frey & George, 2010: 107). The South Africa Government proposed Responsible Tourism as the guiding principle for sustainable tourism development (Goodwin, 2011: 138). The problem is compounded by shortcomings identified in the nature of the research conducted about tourism and communities and the methodologies used. Tourism-Community relationships Theory was applied as the conceptual framework of the study. This theory advocates a holistic approach when conducting research about the impacts of tourism, encompassing community perspectives, attitudes, reactions and considerations for the future development and control of tourism (Pearce, Moscardo & Ross, 1996: 2). The insights gained contributed an emic understanding of the keyinformants’ perspectives imparted in their own language. This study is located in the Interpretevist paradigm, underpinned by Constructivist philosophy. Meaning is created through the reality of key-informants, their perspectives and the interaction of individuals in a community (Cresswell, 2014: 8). The Instrumental Case Study Approach (Stake, 1995) contributed an etic perspective in terms of the researcher’s interpretations. The single, qualitative case was applied to gain deeper insights about the phenomenon of Responsible tourism. The case investigated was Stormsriver Adventures (SRA), an eco-adventure tourism business in the Tsitsikamma tourism destination in the Eastern Cape region of South Africa. SRA is reputed to be business best practice in its implementation of Responsible Tourism. Data triangulation was established through multiple methods of data collection, namely in-depth interviews with key-informants, documentation sourced from them and researcher observation. Data analysis methods, namely direct interpretation, categorical aggregation, pattern seeking and naturalistic generalisations (Stake, 1995), were used. The member checking process assisted with establishing data triangulation as keyinformants corroborated or dispelled the researcher’s interpretation of data. Findings were structured according to within-case themes, namely SRA’s perspective of its Responsible Tourism practices, the community’s perspective of SRA’s Responsible Tourism practices and perspectives about the future development and control of tourism. The study contributes new theoretical insights through applying the inductive approach to selected findings. Findings indicate that the perspectives of the community are divided. SRA keyinformants conveyed positive economic, social and environmental impacts of SRA’s Responsible Tourism practices. Key-informants not directly linked to SRA raised negative economic impacts and questioned the accuracy of SRA’s marketing messages. Within-case conclusions are that it is not the responsibility of one tourism business that practices Responsible Tourism to achieve sustainability within the tourism destination. To this end it is recommended that SRA and the community find common ground and that the misunderstandings that exist, be addressed. The study concludes that in order to achieve successful Responsible Tourism- Community Relationships, a holistically and integrated approach is required. To this end the recommendations made provide an implementation framework within the context of a tourism destination. The study adds value to the field knowledge about the implementation of Responsible Tourism by the private sector in South Africa and also contributes new knowledge to the field of tourism in terms of the particular methodology used.
- Full Text:
- Date Issued: 2015
- Authors: Van Zyl, Shireen Rosemary
- Date: 2015
- Subjects: Sustainable tourism , Tourism -- Management , Economic development
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/4954 , vital:20770
- Description: The research problem was based on the private sector implementation of Responsible Tourism, since 1996, perceived to be slow and challenging (Frey & George, 2010: 107). The South Africa Government proposed Responsible Tourism as the guiding principle for sustainable tourism development (Goodwin, 2011: 138). The problem is compounded by shortcomings identified in the nature of the research conducted about tourism and communities and the methodologies used. Tourism-Community relationships Theory was applied as the conceptual framework of the study. This theory advocates a holistic approach when conducting research about the impacts of tourism, encompassing community perspectives, attitudes, reactions and considerations for the future development and control of tourism (Pearce, Moscardo & Ross, 1996: 2). The insights gained contributed an emic understanding of the keyinformants’ perspectives imparted in their own language. This study is located in the Interpretevist paradigm, underpinned by Constructivist philosophy. Meaning is created through the reality of key-informants, their perspectives and the interaction of individuals in a community (Cresswell, 2014: 8). The Instrumental Case Study Approach (Stake, 1995) contributed an etic perspective in terms of the researcher’s interpretations. The single, qualitative case was applied to gain deeper insights about the phenomenon of Responsible tourism. The case investigated was Stormsriver Adventures (SRA), an eco-adventure tourism business in the Tsitsikamma tourism destination in the Eastern Cape region of South Africa. SRA is reputed to be business best practice in its implementation of Responsible Tourism. Data triangulation was established through multiple methods of data collection, namely in-depth interviews with key-informants, documentation sourced from them and researcher observation. Data analysis methods, namely direct interpretation, categorical aggregation, pattern seeking and naturalistic generalisations (Stake, 1995), were used. The member checking process assisted with establishing data triangulation as keyinformants corroborated or dispelled the researcher’s interpretation of data. Findings were structured according to within-case themes, namely SRA’s perspective of its Responsible Tourism practices, the community’s perspective of SRA’s Responsible Tourism practices and perspectives about the future development and control of tourism. The study contributes new theoretical insights through applying the inductive approach to selected findings. Findings indicate that the perspectives of the community are divided. SRA keyinformants conveyed positive economic, social and environmental impacts of SRA’s Responsible Tourism practices. Key-informants not directly linked to SRA raised negative economic impacts and questioned the accuracy of SRA’s marketing messages. Within-case conclusions are that it is not the responsibility of one tourism business that practices Responsible Tourism to achieve sustainability within the tourism destination. To this end it is recommended that SRA and the community find common ground and that the misunderstandings that exist, be addressed. The study concludes that in order to achieve successful Responsible Tourism- Community Relationships, a holistically and integrated approach is required. To this end the recommendations made provide an implementation framework within the context of a tourism destination. The study adds value to the field knowledge about the implementation of Responsible Tourism by the private sector in South Africa and also contributes new knowledge to the field of tourism in terms of the particular methodology used.
- Full Text:
- Date Issued: 2015
The use of hydrological information to improve flood management-integrated hydrological modelling of the Zambezi River basin
- Vilanculos, Agostinho Chuquelane Fadulo
- Authors: Vilanculos, Agostinho Chuquelane Fadulo
- Date: 2015
- Subjects: Hydrologic models -- Zambezi River Watershed , Watershed management -- Zambezi River Watershed , Water resources development -- Zambezi River Watershed , Flood control -- Zambezi River Watershed , Flood forecasting -- Zambezi River Watershed , Rain gauges -- Zambezi River Watershed
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6054 , http://hdl.handle.net/10962/d1018915
- Description: The recent high profile flooding events – that have occurred in many parts of the world – have drawn attention to the need for new and improved methods for water resources assessment, water management and the modelling of large-scale flooding events. In the case of the Zambezi Basin, a review of the 2000 and 2001 floods identified the need for tools to enable hydrologists to assess and predict daily stream flow and identify the areas that are likely to be affected by flooding. As a way to address the problem, a methodology was set up to derive catchment soil moisture statistics from Earth Observation (EO) data and to study the improvements brought about by an assimilation of this information into hydrological models for improving reservoir management in a data scarce environment. Rainfall data were obtained from the FEWSNet Web site and computed by the National Oceanic and Atmospheric Administration Climatic Prediction Center (NOAA/CPC). These datasets were processed and used to monitor rainfall variability and subsequently fed into a hydrological model to predict the daily flows for the Zambezi River Basin. The hydrological model used was the Geospatial Stream Flow Model (GeoSFM), developed by the United States Geological Survey (USGS). GeoSFM is a spatially semi-distributed physically-based hydrological model, parameterised using spatially distributed topographic data, soil characteristics and land cover data sets available globally from both Remote Sensing and in situ sources. The Satellite rainfall data were validated against data from twenty (20) rainfall gauges located on the Lower Zambezi. However, at several rain gauge stations (especially those with complex topography, which tended to experience high rainfall spatial variability), there was no direct correlation between the satellite estimates and the ground data as recorded in daily time steps. The model was calibrated for seven gauging stations. The calibrated model performed quite well at seven selected locations (R2=0.66 to 0.90, CE=0.51 to 0.88, RSR=0.35 to 0.69, PBIAS=−4.5 to 7.5). The observed data were obtained from the National Water Agencies of the riparian countries. After GeoSFM calibration, the model generated an integration of the flows into a reservoir and hydropower model to optimise the operation of Kariba and Cahora Bassa dams. The Kariba and Cahora Bassa dams were selected because this study considers these two dams as the major infrastructures for controlling and alleviating floods in the Zambezi River Basin. Other dams (such as the Kafue and Itezhi-Thezi) were recognised in terms of their importance but including them was beyond the scope of this study because of financial and time constraints. The licence of the reservoir model was limited to one year for the same reason. The reservoir model used was the MIKE BASIN, a professional engineering software package and quasi-steady-state mass balance modelling tool for integrated river basin and management, developed by the Denmark Hydraulic Institute (DHI) in 2003. The model was parameterised by the geometry of the reservoir basin (level, area, volume relationships) and by the discharge-level (Q-h) relationship of the dam spillways. The integrated modelling system simulated the daily flow variation for all Zambezi River sub-basins between 1998 and 2008 and validated between 2009 and 2011. The resulting streamflows have been expressed in terms of hydrograph comparisons between simulated and observed flow values at the four gauging stations located downstream of Cahora Bassa dam. The integrated model performed well, between observed and forecast streamflows, at four selected gauging stations (R2=0.53 to 0.90, CE=0.50 to 0.80, RSR=0.49 to 0.69, PBIAS=−2.10 to 4.8). From the results of integrated modelling, it was observed that both Kariba and Cahora Bassa are currently being operated based on the maximum rule curve and both remain focused on maximising hydropower production and ensuring dam safety rather than other potential influences by the Zambezi River (such as flood control downstream – where the communities are located – and environmental issues). In addition, the flood mapping analysis demonstrated that the Cahora Bassa dam plays an important part in flood mitigation downstream of the dams. In the absence of optimisation of flow releases from both the Kariba and Cahora Bassa dams, in additional to the contribution of any other tributaries located downstream of the dams, the impact of flooding can be severe. As such, this study has developed new approaches for flood monitoring downstream of the Zambezi Basin, through the application of an integrated modelling system. The modelling system consists of: predicting daily streamflow (using the calibrated GeoSFM), then feeding the predicted streamflow into MIKE BASIN (for checking the operating rules) and to optimise the releases. Therefore, before releases are made, the flood maps can be used as a decision-making tool to both assess the impact of each level of release downstream and to identify the communities likely to be affected by the flood – this ensures that the necessary warnings can be issued before flooding occurs. Finally an integrated flood management tool was proposed – to host the results produced by the integrated system – which would then be accessible for assessment by the different users. These results were expressed in terms of water level (m). Four discharge-level (Q-h) relationships were developed for converting the simulated flow into water level at four selected sites downstream of Cahora Bassa dam – namely: Cahora Bassa dam site, Tete (E-320), Caia (E-291) and Marromeu (E-285). However, the uncertainties in these predictions suggested that improved monitoring systems may be achieved if data access at appropriate scale and quality was improved.
- Full Text:
- Date Issued: 2015
- Authors: Vilanculos, Agostinho Chuquelane Fadulo
- Date: 2015
- Subjects: Hydrologic models -- Zambezi River Watershed , Watershed management -- Zambezi River Watershed , Water resources development -- Zambezi River Watershed , Flood control -- Zambezi River Watershed , Flood forecasting -- Zambezi River Watershed , Rain gauges -- Zambezi River Watershed
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6054 , http://hdl.handle.net/10962/d1018915
- Description: The recent high profile flooding events – that have occurred in many parts of the world – have drawn attention to the need for new and improved methods for water resources assessment, water management and the modelling of large-scale flooding events. In the case of the Zambezi Basin, a review of the 2000 and 2001 floods identified the need for tools to enable hydrologists to assess and predict daily stream flow and identify the areas that are likely to be affected by flooding. As a way to address the problem, a methodology was set up to derive catchment soil moisture statistics from Earth Observation (EO) data and to study the improvements brought about by an assimilation of this information into hydrological models for improving reservoir management in a data scarce environment. Rainfall data were obtained from the FEWSNet Web site and computed by the National Oceanic and Atmospheric Administration Climatic Prediction Center (NOAA/CPC). These datasets were processed and used to monitor rainfall variability and subsequently fed into a hydrological model to predict the daily flows for the Zambezi River Basin. The hydrological model used was the Geospatial Stream Flow Model (GeoSFM), developed by the United States Geological Survey (USGS). GeoSFM is a spatially semi-distributed physically-based hydrological model, parameterised using spatially distributed topographic data, soil characteristics and land cover data sets available globally from both Remote Sensing and in situ sources. The Satellite rainfall data were validated against data from twenty (20) rainfall gauges located on the Lower Zambezi. However, at several rain gauge stations (especially those with complex topography, which tended to experience high rainfall spatial variability), there was no direct correlation between the satellite estimates and the ground data as recorded in daily time steps. The model was calibrated for seven gauging stations. The calibrated model performed quite well at seven selected locations (R2=0.66 to 0.90, CE=0.51 to 0.88, RSR=0.35 to 0.69, PBIAS=−4.5 to 7.5). The observed data were obtained from the National Water Agencies of the riparian countries. After GeoSFM calibration, the model generated an integration of the flows into a reservoir and hydropower model to optimise the operation of Kariba and Cahora Bassa dams. The Kariba and Cahora Bassa dams were selected because this study considers these two dams as the major infrastructures for controlling and alleviating floods in the Zambezi River Basin. Other dams (such as the Kafue and Itezhi-Thezi) were recognised in terms of their importance but including them was beyond the scope of this study because of financial and time constraints. The licence of the reservoir model was limited to one year for the same reason. The reservoir model used was the MIKE BASIN, a professional engineering software package and quasi-steady-state mass balance modelling tool for integrated river basin and management, developed by the Denmark Hydraulic Institute (DHI) in 2003. The model was parameterised by the geometry of the reservoir basin (level, area, volume relationships) and by the discharge-level (Q-h) relationship of the dam spillways. The integrated modelling system simulated the daily flow variation for all Zambezi River sub-basins between 1998 and 2008 and validated between 2009 and 2011. The resulting streamflows have been expressed in terms of hydrograph comparisons between simulated and observed flow values at the four gauging stations located downstream of Cahora Bassa dam. The integrated model performed well, between observed and forecast streamflows, at four selected gauging stations (R2=0.53 to 0.90, CE=0.50 to 0.80, RSR=0.49 to 0.69, PBIAS=−2.10 to 4.8). From the results of integrated modelling, it was observed that both Kariba and Cahora Bassa are currently being operated based on the maximum rule curve and both remain focused on maximising hydropower production and ensuring dam safety rather than other potential influences by the Zambezi River (such as flood control downstream – where the communities are located – and environmental issues). In addition, the flood mapping analysis demonstrated that the Cahora Bassa dam plays an important part in flood mitigation downstream of the dams. In the absence of optimisation of flow releases from both the Kariba and Cahora Bassa dams, in additional to the contribution of any other tributaries located downstream of the dams, the impact of flooding can be severe. As such, this study has developed new approaches for flood monitoring downstream of the Zambezi Basin, through the application of an integrated modelling system. The modelling system consists of: predicting daily streamflow (using the calibrated GeoSFM), then feeding the predicted streamflow into MIKE BASIN (for checking the operating rules) and to optimise the releases. Therefore, before releases are made, the flood maps can be used as a decision-making tool to both assess the impact of each level of release downstream and to identify the communities likely to be affected by the flood – this ensures that the necessary warnings can be issued before flooding occurs. Finally an integrated flood management tool was proposed – to host the results produced by the integrated system – which would then be accessible for assessment by the different users. These results were expressed in terms of water level (m). Four discharge-level (Q-h) relationships were developed for converting the simulated flow into water level at four selected sites downstream of Cahora Bassa dam – namely: Cahora Bassa dam site, Tete (E-320), Caia (E-291) and Marromeu (E-285). However, the uncertainties in these predictions suggested that improved monitoring systems may be achieved if data access at appropriate scale and quality was improved.
- Full Text:
- Date Issued: 2015
The effects of outsourcing practices conducted by organisations in Nairobi
- Authors: Wachira, Wanjungu
- Date: 2015
- Subjects: Contracting out , Industrial management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/4988 , vital:20775
- Description: The purpose of this study is to investigate the relationship between outsourcing and development in Nairobi. The key research question for this study is what are the impacts of outsourcing practices conducted by organisations in Nairobi? Data were obtained from questionnaires distributed in December 2010. A total of 85 profit-making firms in Nairobi with a sample of 165 management employees were selected for this study. The empirical findings obtained relate to four outsourcing theories. Transaction Cost Analysis (TCA) Theory focuses on the cost savings that result from outsourcing. Agency Outsourcing Theory centres on outsourcing firms hiring agents to achieve productivity. Hiring agents may result in permanent staff being retrenched and additional outsourcing personnel being contracted and job creation and/or job loss results. Expectation Confirmation Theory (ECT) emphasises the importance of an outsourcing provider conforming to quality management principles. Resource Based Theory (RBT) proposes that organisations need a collection of resources and capabilities to execute outsourcing successfully. Findings further suggested that outsourcing can yield positive and/or negative outcomes depending on risks encountered, the business environment, company policies, function/s to be outsourced, and the competence and commitment of an outsourcing vendor. To further enhance the positive impact of outsourcing three improvements need to be executed: formulation of standard policies, price regulations, and commitment of outsourcing firms in adhering to set contract deadlines. It is suggested that the following would allow organisations to gain more from outsourcing in the future: the adoption of international/offshore outsourcing practices, more commitment by outsourcing consultants, the standardisation of charges for outsourcing contracts, and the use of new technology that would improve how outsourcing is conducted. It is concluded that the positive impacts of outsourcing would foster development to some extent while the possible negative impact of outsourcing would impede development.
- Full Text:
- Date Issued: 2015
- Authors: Wachira, Wanjungu
- Date: 2015
- Subjects: Contracting out , Industrial management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/4988 , vital:20775
- Description: The purpose of this study is to investigate the relationship between outsourcing and development in Nairobi. The key research question for this study is what are the impacts of outsourcing practices conducted by organisations in Nairobi? Data were obtained from questionnaires distributed in December 2010. A total of 85 profit-making firms in Nairobi with a sample of 165 management employees were selected for this study. The empirical findings obtained relate to four outsourcing theories. Transaction Cost Analysis (TCA) Theory focuses on the cost savings that result from outsourcing. Agency Outsourcing Theory centres on outsourcing firms hiring agents to achieve productivity. Hiring agents may result in permanent staff being retrenched and additional outsourcing personnel being contracted and job creation and/or job loss results. Expectation Confirmation Theory (ECT) emphasises the importance of an outsourcing provider conforming to quality management principles. Resource Based Theory (RBT) proposes that organisations need a collection of resources and capabilities to execute outsourcing successfully. Findings further suggested that outsourcing can yield positive and/or negative outcomes depending on risks encountered, the business environment, company policies, function/s to be outsourced, and the competence and commitment of an outsourcing vendor. To further enhance the positive impact of outsourcing three improvements need to be executed: formulation of standard policies, price regulations, and commitment of outsourcing firms in adhering to set contract deadlines. It is suggested that the following would allow organisations to gain more from outsourcing in the future: the adoption of international/offshore outsourcing practices, more commitment by outsourcing consultants, the standardisation of charges for outsourcing contracts, and the use of new technology that would improve how outsourcing is conducted. It is concluded that the positive impacts of outsourcing would foster development to some extent while the possible negative impact of outsourcing would impede development.
- Full Text:
- Date Issued: 2015
Wolfgang Koeppens auseinandersetzung mit der tradition: aspekte der intertextualität in der so genannten nachkriegs‐trilogie
- Authors: Weber, Undine S
- Date: 2015
- Subjects: Koeppen, Wolfgang, 1906-1996 -- Criticism and interpretation , Koeppen, Wolfgang, 1906-1996 -- Works -- 1986 , German fiction -- 20th century -- History and criticism
- Language: German
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3658 , http://hdl.handle.net/10962/d1020833
- Description: Wolfgang Koeppen’s three post‐war novels have often been called a trilogy, purely based on their publication in rapid succession in the early 1950s. This study establishes a connection between the works by looking at their roots in Irish, Anglo‐American, French and German modernism, and shows up links between Wolfgang Koeppen, James Joyce, E.E. Cummings, Charles Baudelaire and Thomas Mann. This comparative analysis concludes, by integrating socio‐political factors of life in West Germany after World War II, that Koeppen transcends the modernist tradition – the fact that modernism has become tradition, i.e. it has become “classic”, in contradiction to being “modern”. Koeppen’s texts do not only allude to and build on classic texts and refer to stylistic and narrative modernist elements such as stream‐of‐consciousness and sketching a fragmented society in turmoil; the very act of recurring to myths and texts of the Western canon in order to depict the disaffected individual is an almost post‐modern one.
- Full Text:
- Date Issued: 2015
- Authors: Weber, Undine S
- Date: 2015
- Subjects: Koeppen, Wolfgang, 1906-1996 -- Criticism and interpretation , Koeppen, Wolfgang, 1906-1996 -- Works -- 1986 , German fiction -- 20th century -- History and criticism
- Language: German
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3658 , http://hdl.handle.net/10962/d1020833
- Description: Wolfgang Koeppen’s three post‐war novels have often been called a trilogy, purely based on their publication in rapid succession in the early 1950s. This study establishes a connection between the works by looking at their roots in Irish, Anglo‐American, French and German modernism, and shows up links between Wolfgang Koeppen, James Joyce, E.E. Cummings, Charles Baudelaire and Thomas Mann. This comparative analysis concludes, by integrating socio‐political factors of life in West Germany after World War II, that Koeppen transcends the modernist tradition – the fact that modernism has become tradition, i.e. it has become “classic”, in contradiction to being “modern”. Koeppen’s texts do not only allude to and build on classic texts and refer to stylistic and narrative modernist elements such as stream‐of‐consciousness and sketching a fragmented society in turmoil; the very act of recurring to myths and texts of the Western canon in order to depict the disaffected individual is an almost post‐modern one.
- Full Text:
- Date Issued: 2015
The impact of domain knowledge-driven variable derivation on classifier performance for corporate data mining
- Authors: Welcker, Laura Joana Maria
- Date: 2015
- Subjects: Data mining , Business -- Data processing , Database management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/5009 , vital:20778
- Description: The technological progress in terms of increasing computational power and growing virtual space to collect data offers great potential for businesses to benefit from data mining applications. Data mining can create a competitive advantage for corporations by discovering business relevant information, such as patterns, relationships, and rules. The role of the human user within the data mining process is crucial, which is why the research area of domain knowledge becomes increasingly important. This thesis investigates the impact of domain knowledge-driven variable derivation on classifier performance for corporate data mining. Domain knowledge is defined as methodological, data and business know-how. The thesis investigates the topic from a new perspective by shifting the focus from a one-sided approach, namely a purely analytic or purely theoretical approach towards a target group-oriented (researcher and practitioner) approach which puts the methodological aspect by means of a scientific guideline in the centre of the research. In order to ensure feasibility and practical relevance of the guideline, it is adapted and applied to the requirements of a practical business case. Thus, the thesis examines the topic from both perspectives, a theoretical and practical perspective. Therewith, it overcomes the limitation of a one-sided approach which mostly lacks practical relevance or generalisability of the results. The primary objective of this thesis is to provide a scientific guideline which should enable both practitioners and researchers to move forward the domain knowledge-driven research for variable derivation on a corporate basis. In the theoretical part, a broad overview of the main aspects which are necessary to undertake the research are given, such as the concept of domain knowledge, the data mining task of classification, variable derivation as a subtask of data preparation, and evaluation techniques. This part of the thesis refers to the methodological aspect of domain knowledge. In the practical part, a research design is developed for testing six hypotheses related to domain knowledge-driven variable derivation. The major contribution of the empirical study is concerned with testing the impact of domain knowledge on a real business data set compared to the impact of a standard and randomly derived data set. The business application of the research is a binary classification problem in the domain of an insurance business, which deals with the prediction of damages in legal expenses insurances. Domain knowledge is expressed through deriving the corporate variables by means of the business and data-driven constructive induction strategy. Six variable derivation steps are investigated: normalisation, instance relation, discretisation, categorical encoding, ratio, and multivariate mathematical function. The impact of the domain knowledge is examined by pairwise (with and without derived variables) performance comparisons for five classification techniques (decision trees, naive Bayes, logistic regression, artificial neural networks, k-nearest neighbours). The impact is measured by two classifier performance criteria: sensitivity and area under the ROC-curve (AUC). The McNemar significance test is used to verify the results. Based on the results, two hypotheses are clearly verified and accepted, three hypotheses are partly verified, and one hypothesis had to be rejected on the basis of the case study results. The thesis reveals a significant positive impact of domain knowledge-driven variable derivation on classifier performance for options of all six tested steps. Furthermore, the findings indicate that the classification technique influences the impact of the variable derivation steps, and the bundling of steps has a significant higher performance impact if the variables are derived by using domain knowledge (compared to a non-knowledge application). Finally, the research turns out that an empirical examination of the domain knowledge impact is very complex due to a high level of interaction between the selected research parameters (variable derivation step, classification technique, and performance criteria).
- Full Text:
- Date Issued: 2015
- Authors: Welcker, Laura Joana Maria
- Date: 2015
- Subjects: Data mining , Business -- Data processing , Database management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/5009 , vital:20778
- Description: The technological progress in terms of increasing computational power and growing virtual space to collect data offers great potential for businesses to benefit from data mining applications. Data mining can create a competitive advantage for corporations by discovering business relevant information, such as patterns, relationships, and rules. The role of the human user within the data mining process is crucial, which is why the research area of domain knowledge becomes increasingly important. This thesis investigates the impact of domain knowledge-driven variable derivation on classifier performance for corporate data mining. Domain knowledge is defined as methodological, data and business know-how. The thesis investigates the topic from a new perspective by shifting the focus from a one-sided approach, namely a purely analytic or purely theoretical approach towards a target group-oriented (researcher and practitioner) approach which puts the methodological aspect by means of a scientific guideline in the centre of the research. In order to ensure feasibility and practical relevance of the guideline, it is adapted and applied to the requirements of a practical business case. Thus, the thesis examines the topic from both perspectives, a theoretical and practical perspective. Therewith, it overcomes the limitation of a one-sided approach which mostly lacks practical relevance or generalisability of the results. The primary objective of this thesis is to provide a scientific guideline which should enable both practitioners and researchers to move forward the domain knowledge-driven research for variable derivation on a corporate basis. In the theoretical part, a broad overview of the main aspects which are necessary to undertake the research are given, such as the concept of domain knowledge, the data mining task of classification, variable derivation as a subtask of data preparation, and evaluation techniques. This part of the thesis refers to the methodological aspect of domain knowledge. In the practical part, a research design is developed for testing six hypotheses related to domain knowledge-driven variable derivation. The major contribution of the empirical study is concerned with testing the impact of domain knowledge on a real business data set compared to the impact of a standard and randomly derived data set. The business application of the research is a binary classification problem in the domain of an insurance business, which deals with the prediction of damages in legal expenses insurances. Domain knowledge is expressed through deriving the corporate variables by means of the business and data-driven constructive induction strategy. Six variable derivation steps are investigated: normalisation, instance relation, discretisation, categorical encoding, ratio, and multivariate mathematical function. The impact of the domain knowledge is examined by pairwise (with and without derived variables) performance comparisons for five classification techniques (decision trees, naive Bayes, logistic regression, artificial neural networks, k-nearest neighbours). The impact is measured by two classifier performance criteria: sensitivity and area under the ROC-curve (AUC). The McNemar significance test is used to verify the results. Based on the results, two hypotheses are clearly verified and accepted, three hypotheses are partly verified, and one hypothesis had to be rejected on the basis of the case study results. The thesis reveals a significant positive impact of domain knowledge-driven variable derivation on classifier performance for options of all six tested steps. Furthermore, the findings indicate that the classification technique influences the impact of the variable derivation steps, and the bundling of steps has a significant higher performance impact if the variables are derived by using domain knowledge (compared to a non-knowledge application). Finally, the research turns out that an empirical examination of the domain knowledge impact is very complex due to a high level of interaction between the selected research parameters (variable derivation step, classification technique, and performance criteria).
- Full Text:
- Date Issued: 2015
Friend or foe? : Resolving the status of the submerged macrophyte Myriophyllum spicatum L. (Haloragaceae) in southern Africa
- Weyl, Philip Sebastian Richard
- Authors: Weyl, Philip Sebastian Richard
- Date: 2015
- Subjects: Eurasian watermilfoil -- Africa, Southern , Eurasian watermilfoil -- Biological control
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5933 , http://hdl.handle.net/10962/d1017811
- Description: Myriophyllum spicatum L. (Haloragaceae), a submerged macrophyte, has been recorded in southern Africa since 1829, but only considered problematic as recently as 2005. In light of this, water resource managers are looking to control M. spicatum in southern African water bodies where it is problematic. Amongst control options available in South Africa, biological control is potentially the most cost effective and sustainable option for M. spicatum. However, there is a debate over the status of this plant in southern Africa with several authors reporting it as a native component of the aquatic ecosystem, while others argue that it has been introduced from Europe or Asia. The aim of this thesis is to use a multifaceted approach to resolve the status of M. spicatum, by studying aspects of its history, distribution, mechanisms of its adaptations, biotic interactions and genetic relationships in southern Africa. By resolving the status of this plant as either native or exotic, appropriate management strategies can be initiated for its control in situations where it is considered a problem.A review of the evidence collected from this thesis does not provide convincing evidence for the anthropogenic introduction of M. spicatum into southern Africa, and it is probably native to the region. The disjunct distribution as well as regular local extinctions of populations is relatively common for species that are at the edge of their range. The populations in southern Africa could thus be relics from a much wider distribution in the past. The development of local adaptations in southern Africa provides evidence for this and suggests that the populations have been isolated for a substantial period of time and have had a long evolutionary history in the region. The lack of specialist herbivores should suggest that M. spicatum has been introduced, but the complete lack of herbivores, including generalists, may weaken that argument. The lack of herbivores could be a result of something inherent in the plant, irrespective of a lack of evolutionary history in the region. The genetic evidence suggests a European origin, but is characteristic of a population (southern Africa as a whole) that has been isolated for a considerable time. Despite the findings of this research, M. spicatum is considered problematic in southern Africa and warrants control in certain systems. Whether or not biological control should be a component of the management strategy is open to further debate. The benefits in a southern African context may outweigh the risks, based on the specificity of the biological control agent proposed. However, the perceived negative impacts of M. spicatum are likely to be a symptom of a more serious underlying cause, such as nutrient loading and changes in land use patterns. Therefore the control of this native species is a water resource management issue and not a biological control issue.
- Full Text:
- Date Issued: 2015
- Authors: Weyl, Philip Sebastian Richard
- Date: 2015
- Subjects: Eurasian watermilfoil -- Africa, Southern , Eurasian watermilfoil -- Biological control
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5933 , http://hdl.handle.net/10962/d1017811
- Description: Myriophyllum spicatum L. (Haloragaceae), a submerged macrophyte, has been recorded in southern Africa since 1829, but only considered problematic as recently as 2005. In light of this, water resource managers are looking to control M. spicatum in southern African water bodies where it is problematic. Amongst control options available in South Africa, biological control is potentially the most cost effective and sustainable option for M. spicatum. However, there is a debate over the status of this plant in southern Africa with several authors reporting it as a native component of the aquatic ecosystem, while others argue that it has been introduced from Europe or Asia. The aim of this thesis is to use a multifaceted approach to resolve the status of M. spicatum, by studying aspects of its history, distribution, mechanisms of its adaptations, biotic interactions and genetic relationships in southern Africa. By resolving the status of this plant as either native or exotic, appropriate management strategies can be initiated for its control in situations where it is considered a problem.A review of the evidence collected from this thesis does not provide convincing evidence for the anthropogenic introduction of M. spicatum into southern Africa, and it is probably native to the region. The disjunct distribution as well as regular local extinctions of populations is relatively common for species that are at the edge of their range. The populations in southern Africa could thus be relics from a much wider distribution in the past. The development of local adaptations in southern Africa provides evidence for this and suggests that the populations have been isolated for a substantial period of time and have had a long evolutionary history in the region. The lack of specialist herbivores should suggest that M. spicatum has been introduced, but the complete lack of herbivores, including generalists, may weaken that argument. The lack of herbivores could be a result of something inherent in the plant, irrespective of a lack of evolutionary history in the region. The genetic evidence suggests a European origin, but is characteristic of a population (southern Africa as a whole) that has been isolated for a considerable time. Despite the findings of this research, M. spicatum is considered problematic in southern Africa and warrants control in certain systems. Whether or not biological control should be a component of the management strategy is open to further debate. The benefits in a southern African context may outweigh the risks, based on the specificity of the biological control agent proposed. However, the perceived negative impacts of M. spicatum are likely to be a symptom of a more serious underlying cause, such as nutrient loading and changes in land use patterns. Therefore the control of this native species is a water resource management issue and not a biological control issue.
- Full Text:
- Date Issued: 2015
Molecular systematics and biology of two closely related blowflies : Lucilia sericata and Lucilia cuprina
- Authors: Williams, Kirstin Alexa
- Date: 2015
- Subjects: Lucilia sericata , Lucilia cuprina
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5934 , http://hdl.handle.net/10962/d1017812
- Description: The greenbottle blowflies, Lucilia sericata (Meigen, 1826) and Lucilia cuprina (Wiedemann, 1830) (Diptera: Calliphoridae) are very difficult to distinguish on the basis of their external morphology. The literature suggests that these two species may be interbreeding. Sequencing two nuclear (28S rRNA and Period) and one mitochondrial (COI) gene indicated that there has been an ancient hybridization event and that mtDNA of L. sericata has become fixed in a lineage of L. cuprina through mtDNA introgression, possibly involving Wolbachia infection. This has implications for identifications of these species based on mtDNA alone. No study has shown explicitly that hybrids of L. sericata and L. cuprina can be identified morphologically. Morphological characters used to identify L. sericata and L. cuprina were scored and tested using specimens of both species and known hybrids. Discriminant function analysis of the characters successfully separated the specimens into three unambiguous groups – L. sericata, L. cuprina and hybrids. This is the first evidence that hybrids of these two species can be identified from physical characteristics.Lucilia sericata and L. cuprina have medical, veterinary and forensic importance. Knowing their distribution in South Africa would allow more effective management and utilisation of these flies. Their predicted geographic distributions in South Africa were modelled using maximum entropy analysis of selected climatic variables. The most important environmental variables in modelling their distributions were magnitude of monthly rainfall and the magnitude of the monthly maximum temperature for L. sericata, and the seasonal variation in monthly mean humidity and magnitude of monthly rainfall for L. cuprina. Both species have a widespread distribution in South Africa and one therefore cannot identify specimens of these flies by locality of capture alone.Luciliinae is a diverse and geographically widespread subfamily containing four genera - Hemipyrellia, Lucilia, Dyscritomyia and Hypopygiopsis – that all contain parasitic species ranging from saprophages to obligate parasites. The phylogenetic relationships between these genera are unclear. The 28S rRNA, COI and Period genes of 14 species of Lucilia and Hemipyrellia were partially sequenced and analysed together with 11sequences from GenBank and the Barcode of Life Database (BOLD). Lucilia sericata and L. cuprina were shown to be sister-species. Three cases of paraphylly were identified within Lucilia that affects identification of these species using mtDNA alone. Hemipyrellia consistently caused Lucilia to be paraphyletic when it was included in analyses, so Hemipyrellia should be synonymized with Lucilia. The relationships of Dyscritomyia and Hypopygiopsis to Lucilia are unclear and further studies are required. No geographic pattern was found within the different forms of parasitism within this group, but the different degrees of parasitism were phylogenetically clustered.
- Full Text:
- Date Issued: 2015
- Authors: Williams, Kirstin Alexa
- Date: 2015
- Subjects: Lucilia sericata , Lucilia cuprina
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5934 , http://hdl.handle.net/10962/d1017812
- Description: The greenbottle blowflies, Lucilia sericata (Meigen, 1826) and Lucilia cuprina (Wiedemann, 1830) (Diptera: Calliphoridae) are very difficult to distinguish on the basis of their external morphology. The literature suggests that these two species may be interbreeding. Sequencing two nuclear (28S rRNA and Period) and one mitochondrial (COI) gene indicated that there has been an ancient hybridization event and that mtDNA of L. sericata has become fixed in a lineage of L. cuprina through mtDNA introgression, possibly involving Wolbachia infection. This has implications for identifications of these species based on mtDNA alone. No study has shown explicitly that hybrids of L. sericata and L. cuprina can be identified morphologically. Morphological characters used to identify L. sericata and L. cuprina were scored and tested using specimens of both species and known hybrids. Discriminant function analysis of the characters successfully separated the specimens into three unambiguous groups – L. sericata, L. cuprina and hybrids. This is the first evidence that hybrids of these two species can be identified from physical characteristics.Lucilia sericata and L. cuprina have medical, veterinary and forensic importance. Knowing their distribution in South Africa would allow more effective management and utilisation of these flies. Their predicted geographic distributions in South Africa were modelled using maximum entropy analysis of selected climatic variables. The most important environmental variables in modelling their distributions were magnitude of monthly rainfall and the magnitude of the monthly maximum temperature for L. sericata, and the seasonal variation in monthly mean humidity and magnitude of monthly rainfall for L. cuprina. Both species have a widespread distribution in South Africa and one therefore cannot identify specimens of these flies by locality of capture alone.Luciliinae is a diverse and geographically widespread subfamily containing four genera - Hemipyrellia, Lucilia, Dyscritomyia and Hypopygiopsis – that all contain parasitic species ranging from saprophages to obligate parasites. The phylogenetic relationships between these genera are unclear. The 28S rRNA, COI and Period genes of 14 species of Lucilia and Hemipyrellia were partially sequenced and analysed together with 11sequences from GenBank and the Barcode of Life Database (BOLD). Lucilia sericata and L. cuprina were shown to be sister-species. Three cases of paraphylly were identified within Lucilia that affects identification of these species using mtDNA alone. Hemipyrellia consistently caused Lucilia to be paraphyletic when it was included in analyses, so Hemipyrellia should be synonymized with Lucilia. The relationships of Dyscritomyia and Hypopygiopsis to Lucilia are unclear and further studies are required. No geographic pattern was found within the different forms of parasitism within this group, but the different degrees of parasitism were phylogenetically clustered.
- Full Text:
- Date Issued: 2015
Investigating the radical democratic potential of social media use by new social movements in South Africa
- Authors: Zdanow, Carla
- Date: 2015
- Subjects: Social media -- South Africa , Social movements -- South Africa , Neoliberalism -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/4310 , vital:20583
- Description: Since its inception, the internet ‒ and in particular Web 2.0 ‒ have been valorized as potentially revolutionary democratic spaces. Despite the emergence of concerns over the progressively neoliberal orientation and narcissistic effects of the internet, evidence of the radical democratic potential of this media has received considerable attention. This thesis is orientated around both an exploration of such evidence, and a consideration of its relevance for South Africa. In this regard, the thesis commences with an exploration of the neoliberal underpinnings of the internet and the growing translation of dominant neoliberal discourses into the online practices of mainstream liberal democratic politics. Focus then shifts toward the mounting influence of alternative radical democratic positions online, through an investigation of the virtual manifestations of deliberative, autonomous, and agonistic approaches to radical democracy. And following an examination of the online political practices of selected recent global social movements, the primacy of agonism in online expressions of radical democracy is advanced. In turn, resonances and dissonances between the online activity and practices of such global social movements, and the use of the internet and social media by well-known South African new social movements, are explored. Finally, this thesis concludes by recommending a fourfold new media approach through which the agonistic radical democratic potential of the internet can be realized more fully by the new social movements of South Africa.
- Full Text:
- Date Issued: 2015
- Authors: Zdanow, Carla
- Date: 2015
- Subjects: Social media -- South Africa , Social movements -- South Africa , Neoliberalism -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/4310 , vital:20583
- Description: Since its inception, the internet ‒ and in particular Web 2.0 ‒ have been valorized as potentially revolutionary democratic spaces. Despite the emergence of concerns over the progressively neoliberal orientation and narcissistic effects of the internet, evidence of the radical democratic potential of this media has received considerable attention. This thesis is orientated around both an exploration of such evidence, and a consideration of its relevance for South Africa. In this regard, the thesis commences with an exploration of the neoliberal underpinnings of the internet and the growing translation of dominant neoliberal discourses into the online practices of mainstream liberal democratic politics. Focus then shifts toward the mounting influence of alternative radical democratic positions online, through an investigation of the virtual manifestations of deliberative, autonomous, and agonistic approaches to radical democracy. And following an examination of the online political practices of selected recent global social movements, the primacy of agonism in online expressions of radical democracy is advanced. In turn, resonances and dissonances between the online activity and practices of such global social movements, and the use of the internet and social media by well-known South African new social movements, are explored. Finally, this thesis concludes by recommending a fourfold new media approach through which the agonistic radical democratic potential of the internet can be realized more fully by the new social movements of South Africa.
- Full Text:
- Date Issued: 2015
Neurocognitive effects of head and body collisions on club level rugby union players
- Authors: Zoccola, Diana
- Date: 2015
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3257 , http://hdl.handle.net/10962/d1016397
- Description: The objective of the study was to investigate the cumulative neurocognitive effects of repetitive concussive and subconcussive events in club level Rugby Union (hereafter rugby) during the course of one rugby season, in a combined group and individualized case-based approach. Amateur adult club level rugby players (n = 20) were compared with a non-contact control group (n = 22) of equivalent age, years of education and estimated IQ (p = > .05, in all instances), although the two groups were clearly differentiated on the basis of a history of reported concussions (p = < .05). Video analyses documented the tackling maneuvers observed amongst the players during all matches across the rugby season revealing a sobering average of more than a thousand tackles per player, excluding any contact practice sessions. Five rugby players (n = 5) who were observed to have a head jarring event were also isolated for individualized postconcussive follow-up analysis of their neurocognitive profiles. Measures included the ImPACT Verbal and Visual Memory, Visual Motor Speed and Reaction Time composites and the Purdue Pegboard. Independent and dependent statistical analyses were employed to compare the rugby versus control group neurocognitive test profiles at and between the three test intervals. Correlational analyses explored the association between concussion, tackling and neurocognitive test outcomes. Descriptive comparisons of individual neurocognitive test scores with normative data were employed for the case analyses. Taken together, the results implicated vulnerability amongst club rugby players on the motor and speeded tasks, with less robust indications on the memory tasks. While limited in terms of its small sample size, it is considered that the outcome of the study was rendered more robust by virtue of being methodologically multifaceted with heuristic implications for future research studies in the area. The novel inclusion of tackling data as well as fine-tuned case analyses, were of particular relevance in that regard. The results add to a growing body of literature that implicates deleterious neurocognitive effects in participants of a sport such as rugby due to repetitive head jarring incidents that are intrinsic to the game.
- Full Text:
- Date Issued: 2015
- Authors: Zoccola, Diana
- Date: 2015
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3257 , http://hdl.handle.net/10962/d1016397
- Description: The objective of the study was to investigate the cumulative neurocognitive effects of repetitive concussive and subconcussive events in club level Rugby Union (hereafter rugby) during the course of one rugby season, in a combined group and individualized case-based approach. Amateur adult club level rugby players (n = 20) were compared with a non-contact control group (n = 22) of equivalent age, years of education and estimated IQ (p = > .05, in all instances), although the two groups were clearly differentiated on the basis of a history of reported concussions (p = < .05). Video analyses documented the tackling maneuvers observed amongst the players during all matches across the rugby season revealing a sobering average of more than a thousand tackles per player, excluding any contact practice sessions. Five rugby players (n = 5) who were observed to have a head jarring event were also isolated for individualized postconcussive follow-up analysis of their neurocognitive profiles. Measures included the ImPACT Verbal and Visual Memory, Visual Motor Speed and Reaction Time composites and the Purdue Pegboard. Independent and dependent statistical analyses were employed to compare the rugby versus control group neurocognitive test profiles at and between the three test intervals. Correlational analyses explored the association between concussion, tackling and neurocognitive test outcomes. Descriptive comparisons of individual neurocognitive test scores with normative data were employed for the case analyses. Taken together, the results implicated vulnerability amongst club rugby players on the motor and speeded tasks, with less robust indications on the memory tasks. While limited in terms of its small sample size, it is considered that the outcome of the study was rendered more robust by virtue of being methodologically multifaceted with heuristic implications for future research studies in the area. The novel inclusion of tackling data as well as fine-tuned case analyses, were of particular relevance in that regard. The results add to a growing body of literature that implicates deleterious neurocognitive effects in participants of a sport such as rugby due to repetitive head jarring incidents that are intrinsic to the game.
- Full Text:
- Date Issued: 2015