A new broom sweeps clean: the economic and cultural value of grass brooms in the Eastern Cape Province, South Africa
- Cocks, Michelle L, Dold, Anthony P
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141382 , vital:37967 , DOI: 10.1080/14728028.2004.9752477
- Description: In southern Africa over the last twenty years, much attention has been given to the importance of NTFPs for rural livelihoods through their household consumption and sale. They have been classified as having either subsistence consumption or commercial values. These values are mostly related to their utilitarian functions, but recent studies show that NTFPs also hold strong cultural functions. Such cultural functions can play a role in both rural and urban livelihoods; consequently the values of NTFPs may be related to both utilitarian and cultural functions. This paper demonstrates the cultural functions of grass brooms in urban areas in South Africa and the impact of their trade on income generation in rural areas, and discusses the concept of culture as a significant factor in the understanding of the role of NTFPs in livelihoods, and their values.
- Full Text:
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141382 , vital:37967 , DOI: 10.1080/14728028.2004.9752477
- Description: In southern Africa over the last twenty years, much attention has been given to the importance of NTFPs for rural livelihoods through their household consumption and sale. They have been classified as having either subsistence consumption or commercial values. These values are mostly related to their utilitarian functions, but recent studies show that NTFPs also hold strong cultural functions. Such cultural functions can play a role in both rural and urban livelihoods; consequently the values of NTFPs may be related to both utilitarian and cultural functions. This paper demonstrates the cultural functions of grass brooms in urban areas in South Africa and the impact of their trade on income generation in rural areas, and discusses the concept of culture as a significant factor in the understanding of the role of NTFPs in livelihoods, and their values.
- Full Text:
A process-genre approach to teaching argumentative writing to grade nine learners
- Authors: Elson, Jillian Margaret
- Date: 2012
- Subjects: English language -- Rhetoric -- Study and teaching (Secondary) English language -- Writing -- Study and teaching (Secondary) Written communication
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1714 , http://hdl.handle.net/10962/d1003597
- Description: This action research study aimed to improve teaching and learning of argumentative writing through a process-genre approach. Learners were carefully guided through the processes of writing the argumentative genre, with the focus being on teaching of the genre and on the structural conventions of writing arguments. Participants were a class of grade nine learners who speak English as a first language. They were chosen for this study as Grade Nine is a crucial year for writing development before learners enter the senior phase and are met with heightened expectations in the curriculum, that often they struggle to meet, as their writing has not been sufficiently developed to an academic level. The focus of writing in Grade Nine is on narrative and prose, so this writing intervention, in which a teaching module was developed in collaboration with the 1eamers, aimed to broaden their writing skills and provide them with a head start in leaming the fine art of argumentation, as this is a useful skill to acquire for purposes even beyond the classroom. Genre theorists advocate the importance of teaching genres to leamers at a young age, as it allows them access into different communities of discourse, as they become aware and understand the conventions held by a patiicular community, and realize the purpose of different styles of writing for effectively communicating, which prepares them to meet the expectations of their audience. Teaching the structures of different genres therefore allows the writer, and the audience, a framework for understanding the text. The process approach has been widely used by educators as it focuses on explicit teaching of writing processes that are fundamental to leamers' development in writing. Learners need to be carefully guided from the initial stages, to the more complex stages (especially in argumentative writing which has been deemed the most complex genre for learners to master) in order to understand the complexities of constructing an essay in a cohesive way, as they need to consider multiple aspects of writing, such as the linguistic features, rhetorical features and structural features of the genre and unify them into a sound argument. This takes time, practice and revision, and extensive feedback is required. The process-genre approach proved to be successful in this study, as leamers showed remarkable improvements in their writing from the initial stages of writing to the final drafts of their essays. The findings revealed that explicit teaching of genres and structural elements of writing is vital for ensuring learners' development. Learners require modelling of the genre, scaffolding and careful guidance through step-by-step processes in order to build confidence and express their ideas effectively in written text. The findings indicate the relevance of using the process-genre approach for teaching and learning and that teaching and learning writing is indeed a process that needs more time and practice that is cUiTently allocated in the curriculum.
- Full Text:
- Authors: Elson, Jillian Margaret
- Date: 2012
- Subjects: English language -- Rhetoric -- Study and teaching (Secondary) English language -- Writing -- Study and teaching (Secondary) Written communication
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1714 , http://hdl.handle.net/10962/d1003597
- Description: This action research study aimed to improve teaching and learning of argumentative writing through a process-genre approach. Learners were carefully guided through the processes of writing the argumentative genre, with the focus being on teaching of the genre and on the structural conventions of writing arguments. Participants were a class of grade nine learners who speak English as a first language. They were chosen for this study as Grade Nine is a crucial year for writing development before learners enter the senior phase and are met with heightened expectations in the curriculum, that often they struggle to meet, as their writing has not been sufficiently developed to an academic level. The focus of writing in Grade Nine is on narrative and prose, so this writing intervention, in which a teaching module was developed in collaboration with the 1eamers, aimed to broaden their writing skills and provide them with a head start in leaming the fine art of argumentation, as this is a useful skill to acquire for purposes even beyond the classroom. Genre theorists advocate the importance of teaching genres to leamers at a young age, as it allows them access into different communities of discourse, as they become aware and understand the conventions held by a patiicular community, and realize the purpose of different styles of writing for effectively communicating, which prepares them to meet the expectations of their audience. Teaching the structures of different genres therefore allows the writer, and the audience, a framework for understanding the text. The process approach has been widely used by educators as it focuses on explicit teaching of writing processes that are fundamental to leamers' development in writing. Learners need to be carefully guided from the initial stages, to the more complex stages (especially in argumentative writing which has been deemed the most complex genre for learners to master) in order to understand the complexities of constructing an essay in a cohesive way, as they need to consider multiple aspects of writing, such as the linguistic features, rhetorical features and structural features of the genre and unify them into a sound argument. This takes time, practice and revision, and extensive feedback is required. The process-genre approach proved to be successful in this study, as leamers showed remarkable improvements in their writing from the initial stages of writing to the final drafts of their essays. The findings revealed that explicit teaching of genres and structural elements of writing is vital for ensuring learners' development. Learners require modelling of the genre, scaffolding and careful guidance through step-by-step processes in order to build confidence and express their ideas effectively in written text. The findings indicate the relevance of using the process-genre approach for teaching and learning and that teaching and learning writing is indeed a process that needs more time and practice that is cUiTently allocated in the curriculum.
- Full Text:
A production function for cricket: the South African perspective
- Brock, Kelsey, Fraser, Gavin G C, Botha, Ferdi
- Authors: Brock, Kelsey , Fraser, Gavin G C , Botha, Ferdi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396007 , vital:69143 , xlink:href="https://hdl.handle.net/10520/EJC124240"
- Description: Production functions are common to any productive activity. Although it may not appear obvious, cricket is no different. Production functions in cricket provide a wide range of information, utilised to enhance efficiency and maximize match success. Given these benefits, this study involved the derivation of a production function for the South African SuperSport Series and an analysis of technical efficiency. An econometric analysis was conducted on data from the 2004-2011 cricket seasons and it was concluded that the most optimal strategy for South African teams involved a combination of attacking batting and defensive bowling. Furthermore, South African teams had a relatively low variable substitutability and a high degree of technical efficiency.
- Full Text:
- Authors: Brock, Kelsey , Fraser, Gavin G C , Botha, Ferdi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396007 , vital:69143 , xlink:href="https://hdl.handle.net/10520/EJC124240"
- Description: Production functions are common to any productive activity. Although it may not appear obvious, cricket is no different. Production functions in cricket provide a wide range of information, utilised to enhance efficiency and maximize match success. Given these benefits, this study involved the derivation of a production function for the South African SuperSport Series and an analysis of technical efficiency. An econometric analysis was conducted on data from the 2004-2011 cricket seasons and it was concluded that the most optimal strategy for South African teams involved a combination of attacking batting and defensive bowling. Furthermore, South African teams had a relatively low variable substitutability and a high degree of technical efficiency.
- Full Text:
A qualitative analysis to determine the readiness of rural communities to adopt ICTs: A Siyakhula Living Lab Case Study
- Gumbo, Sibukelo, Jere, Norbert, Terzoli, Alfredo
- Authors: Gumbo, Sibukelo , Jere, Norbert , Terzoli, Alfredo
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431396 , vital:72771
- Description: Rural schools have a pressing need for ICT and Internet services, for them-selves and the surrounding communities. Educators can play a crucial role of fulfilling this need. But how ready are schools, educators and communi-ties to engage with ICT and use it for their empowerment? This paper re-ports the findings of an e-readiness assessment and promotion drive by re-searchers from the Siyakhula Living Lab in parts of the Mbashe Municipali-ty, in South Africa. The Siyakhula Living Lab is a multi-disciplinary, multi-year initiative to foster grassroots innovation in marginalized communities with the aim of improving their lives and economies. The drive was con-ducted to support the expansion of the network of Digital Access Nodes, ie ICT points-of-presence of the Living Lab in the community: this network rep-resents the structural backbone on which all other activities rest. The as-sessment shows that, while the practical difficulties are many, the communi-ties are very eager to engage with ICT and understand fairly well the con-nection between ICT availability and the possibility of improvement in their life conditions.
- Full Text:
- Authors: Gumbo, Sibukelo , Jere, Norbert , Terzoli, Alfredo
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431396 , vital:72771
- Description: Rural schools have a pressing need for ICT and Internet services, for them-selves and the surrounding communities. Educators can play a crucial role of fulfilling this need. But how ready are schools, educators and communi-ties to engage with ICT and use it for their empowerment? This paper re-ports the findings of an e-readiness assessment and promotion drive by re-searchers from the Siyakhula Living Lab in parts of the Mbashe Municipali-ty, in South Africa. The Siyakhula Living Lab is a multi-disciplinary, multi-year initiative to foster grassroots innovation in marginalized communities with the aim of improving their lives and economies. The drive was con-ducted to support the expansion of the network of Digital Access Nodes, ie ICT points-of-presence of the Living Lab in the community: this network rep-resents the structural backbone on which all other activities rest. The as-sessment shows that, while the practical difficulties are many, the communi-ties are very eager to engage with ICT and understand fairly well the con-nection between ICT availability and the possibility of improvement in their life conditions.
- Full Text:
A quantitative post-release evaluation of biological control of water lettuce, Pistia stratiotes L. (Araceae) by the weevil Neohydronomus affinis Hustache (Coleoptera: Curculionidae) at Cape Recife Nature Reserve, Eastern Cape Province, South Africa
- Moore, Gareth R, Hill, Martin P
- Authors: Moore, Gareth R , Hill, Martin P
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6839 , http://hdl.handle.net/10962/d1010987 , http://dx.doi.org/10.4001/003.020.0217 , https://orcid.org/0000-0003-0579-5298
- Description: [from the introduction] Water lettuce, Pistia stratiotes L. (Araceae) is recognized as being among the world’s worst aquatic weeds. In its adventive range, the plant forms extensive mats capable of blocking navigation channels, impeding water flow in irrigation and flood control canals, and disrupting hydropower generation (Holm et al. 1977). Dense mats of the weed prevent light penetration into the water column which negatively affects submerged aquatic plant communities, causing a lowering of the oxygen concentration and thereby reducing benthic invertebrate and fish populations (Neuenschwander et al. 2009).
- Full Text:
- Authors: Moore, Gareth R , Hill, Martin P
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6839 , http://hdl.handle.net/10962/d1010987 , http://dx.doi.org/10.4001/003.020.0217 , https://orcid.org/0000-0003-0579-5298
- Description: [from the introduction] Water lettuce, Pistia stratiotes L. (Araceae) is recognized as being among the world’s worst aquatic weeds. In its adventive range, the plant forms extensive mats capable of blocking navigation channels, impeding water flow in irrigation and flood control canals, and disrupting hydropower generation (Holm et al. 1977). Dense mats of the weed prevent light penetration into the water column which negatively affects submerged aquatic plant communities, causing a lowering of the oxygen concentration and thereby reducing benthic invertebrate and fish populations (Neuenschwander et al. 2009).
- Full Text:
A reflection on research design and methodologies used in the social learning literature
- Rodela, Romina, Cundill, Georgina, Wals, Arjen
- Authors: Rodela, Romina , Cundill, Georgina , Wals, Arjen
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436584 , vital:73284 , ISBN 978-1-919991-81-8 , 10.13140/2.1.1855.3285
- Description: This paper reviews the social learning research literature related to natu-ral resources management. It provides an overview of the social learning discourse and then comments on methodologies used by social learning researchers. The present study is part of an activity that looked at the so-cial learning methodological agenda. As such it is a companion study to the analysis reported in Rodela, Cundill and Wals (under review) where aspects of knowledge production and validation in social learning re-search were considered. The present analysis adds to this a deconstruc-tion of the research designs used and a reflection on methodologies that can best support the study of learning processes in a natural resource management context.
- Full Text:
- Authors: Rodela, Romina , Cundill, Georgina , Wals, Arjen
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436584 , vital:73284 , ISBN 978-1-919991-81-8 , 10.13140/2.1.1855.3285
- Description: This paper reviews the social learning research literature related to natu-ral resources management. It provides an overview of the social learning discourse and then comments on methodologies used by social learning researchers. The present study is part of an activity that looked at the so-cial learning methodological agenda. As such it is a companion study to the analysis reported in Rodela, Cundill and Wals (under review) where aspects of knowledge production and validation in social learning re-search were considered. The present analysis adds to this a deconstruc-tion of the research designs used and a reflection on methodologies that can best support the study of learning processes in a natural resource management context.
- Full Text:
A review of the alderfly genus Leptosialis Esben-Petersen (Megaloptera, Sialidae) with description of a new species from South Africa
- Price, Benjamin W, Liu, Xingyue, de Moor, Ferdy C, Villet, Martin H
- Authors: Price, Benjamin W , Liu, Xingyue , de Moor, Ferdy C , Villet, Martin H
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441461 , vital:73891 , https://zookeys.pensoft.net/articles.php?id=2856
- Description: The monotypic South African alderfly genus Leptosialis Esben-Petersen, 1920 is reviewed and Leptosialis africana Esben-Petersen, 1920 is redescribed. In the process a new species of alderfly Leptosialis necopinata sp. n. from the Eastern Cape and KwaZulu-Natal provinces of South Africa is recognised and described. Within Sialidae the new species most closely resembles Leptosialis africana. A key to the two species of Leptosialis using both adult and larval characters is provided.
- Full Text:
- Authors: Price, Benjamin W , Liu, Xingyue , de Moor, Ferdy C , Villet, Martin H
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441461 , vital:73891 , https://zookeys.pensoft.net/articles.php?id=2856
- Description: The monotypic South African alderfly genus Leptosialis Esben-Petersen, 1920 is reviewed and Leptosialis africana Esben-Petersen, 1920 is redescribed. In the process a new species of alderfly Leptosialis necopinata sp. n. from the Eastern Cape and KwaZulu-Natal provinces of South Africa is recognised and described. Within Sialidae the new species most closely resembles Leptosialis africana. A key to the two species of Leptosialis using both adult and larval characters is provided.
- Full Text:
A search for coherence: Social learning in natural resource management
- Cundill, Georgina, Rodela, Romina
- Authors: Cundill, Georgina , Rodela, Romina
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436597 , vital:73285 , ISBN 978-1-919991-81-8 , https://transformativelearning.education/wp-content/uploads/2013/01/reviews-on-social-learning-literature.pdf
- Description: This paper presents the results of a review process that sought to disen-tangle the different ways in which social learning is conceptualised in nat-ural resource management. We begin with an historical review that seeks to reveal the roots of social learning theory in natural resource manage-ment. Based on this analysis, we develop typologies of statements about the processes that support social learning, and the outcomes of these processes. We then conduct a systematic review of the literature to as-sess the extent to which there is an emerging consensus around these typologies. We conclude that a key source of the confusion currently prevalent in the literature, stems from the fact that the same term is used to refer to quite different processes, which have different outcomes as their goal. To find our way out of the current confusion in the literature, researchers must be explicit about the definitions that they adopt for so-cial learning, and locate these definitions within the historical develop-ment of thinking around social learning in this field. Active debate about appropriate definitions for social learning, based on empirical studies and experience, should form the basis of this field of research in the coming years.
- Full Text:
- Authors: Cundill, Georgina , Rodela, Romina
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436597 , vital:73285 , ISBN 978-1-919991-81-8 , https://transformativelearning.education/wp-content/uploads/2013/01/reviews-on-social-learning-literature.pdf
- Description: This paper presents the results of a review process that sought to disen-tangle the different ways in which social learning is conceptualised in nat-ural resource management. We begin with an historical review that seeks to reveal the roots of social learning theory in natural resource manage-ment. Based on this analysis, we develop typologies of statements about the processes that support social learning, and the outcomes of these processes. We then conduct a systematic review of the literature to as-sess the extent to which there is an emerging consensus around these typologies. We conclude that a key source of the confusion currently prevalent in the literature, stems from the fact that the same term is used to refer to quite different processes, which have different outcomes as their goal. To find our way out of the current confusion in the literature, researchers must be explicit about the definitions that they adopt for so-cial learning, and locate these definitions within the historical develop-ment of thinking around social learning in this field. Active debate about appropriate definitions for social learning, based on empirical studies and experience, should form the basis of this field of research in the coming years.
- Full Text:
A South African perspective on the tax implications of virtual asset accumulation and transactions stemming from persistent virtual worlds
- Authors: Haupt, Alexander
- Date: 2012
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:884 , http://hdl.handle.net/10962/d1001638
- Description: Massively multiplayer online role-playing games are growing in popularity with millions of people participating in these persistent online environments on a daily basis. Accompanying the ever-increasing subscription numbers is an increase in real money trade transactions stemming from these game worlds. The research question to be addressed in this thesis is whether transactions stemming from virtual worlds have real-world taxation consequences. The goal of this research is to determine the taxability of virtual assets obtained in structured as well as unstructured virtual environments and to attempt to establish the differences between capital and revenue receipts in these virtual realms, taking into account the nature of a receipt. The general deduction formula is applied to establish the deductibility of expenditure incurred whilst participating in these virtual environments. Sundry matters such as Value-Added Tax, donations tax, the withholding tax on gambling gains and tax avoidance will also be addressed. The methodology adopted for the research could best be described as interpretative, aimed at analysing and interpreting the relationship between real world taxes and persistent virtual worlds and the transactions that stem from participation therein. The research is based purely on documentary evidence. After applying relevant tax legislation to virtual economies it became evident that merely because virtual assets only exist in virtual reality does not necessarily preclude them real world tax consequences. It was concluded, however, that it is not practical for the South African Revenue Service to monitor all virtual world transactions or for participant taxpayers to calculate the real world value of each and every asset acquired in-world. As a result, it was concluded that real world tax consequences should only be applied in situations where participants actually convert their virtual assets into real world currency.
- Full Text:
- Authors: Haupt, Alexander
- Date: 2012
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:884 , http://hdl.handle.net/10962/d1001638
- Description: Massively multiplayer online role-playing games are growing in popularity with millions of people participating in these persistent online environments on a daily basis. Accompanying the ever-increasing subscription numbers is an increase in real money trade transactions stemming from these game worlds. The research question to be addressed in this thesis is whether transactions stemming from virtual worlds have real-world taxation consequences. The goal of this research is to determine the taxability of virtual assets obtained in structured as well as unstructured virtual environments and to attempt to establish the differences between capital and revenue receipts in these virtual realms, taking into account the nature of a receipt. The general deduction formula is applied to establish the deductibility of expenditure incurred whilst participating in these virtual environments. Sundry matters such as Value-Added Tax, donations tax, the withholding tax on gambling gains and tax avoidance will also be addressed. The methodology adopted for the research could best be described as interpretative, aimed at analysing and interpreting the relationship between real world taxes and persistent virtual worlds and the transactions that stem from participation therein. The research is based purely on documentary evidence. After applying relevant tax legislation to virtual economies it became evident that merely because virtual assets only exist in virtual reality does not necessarily preclude them real world tax consequences. It was concluded, however, that it is not practical for the South African Revenue Service to monitor all virtual world transactions or for participant taxpayers to calculate the real world value of each and every asset acquired in-world. As a result, it was concluded that real world tax consequences should only be applied in situations where participants actually convert their virtual assets into real world currency.
- Full Text:
A spatial and temporal analysis of the changes in alien macrophyte communities and a baseline assessment of the macroinvertebrates associated with Eurasian watermilfoil, Myriophyllum spicatum L. (Haloragaceae) in the Vaal River
- Authors: Fordham, Colin Justin
- Date: 2012
- Subjects: Water hyacinth -- Control -- South Africa , Aquatic weeds -- Control -- South Africa , Eurasian watermilfoil -- South Africa , Water quality management -- South Africa , Freshwater invertebrates -- Ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5767 , http://hdl.handle.net/10962/d1005455 , Water hyacinth -- Control -- South Africa , Aquatic weeds -- Control -- South Africa , Eurasian watermilfoil -- South Africa , Water quality management -- South Africa , Freshwater invertebrates -- Ecology -- South Africa
- Description: The majority of South Africa’s fresh water (lotic and lentic), is eutrophic and this has resulted in water hyacinth, Eichhornia crassipes (C.Mart.) Solms. (Pontederiaceae) becoming South Africa’s most damaging aquatic macrophyte. Recently however, concerns have also been voiced over the presence of highly invasive submerged macrophyte species, such as Eurasian water-milfoil, Myriophyllum spicatum L. (Haloragaceae) in the Vaal River. Interaction studies between floating and submerged macrophytes have shown that floating macrophyte dominance restricts light penetration into the water column shading out submerged macrophytes while submerged macrophyte dominance reduces nutrient availability in the water column limiting floating macrophyte growth. This cycle ensures that these species cannot coexist in the same habitat for extended periods of time. The aims of this thesis were to: 1. Investigate changes in the historical and current macrophyte dominance in the Vaal River 2. Determine whether these changes could be attributed to stochastic events, such as floods and herbicide control measures. 3. The physio-chemical conditions of the water column, and whether pressure from herbivory by macroinvertebrates had possibly influenced Eurasian water-milfoil’s ability to dominate. Spatial and temporal analysis of satellite imagery revealed that water hyacinth and submerged macrophyte species dominated different regions of the study area over different periods of time from 2006 to 2010. This was significantly correlated with nitrate concentrations of the water column. One of the lower Vaal River Water Management Areas (WMA) had changed from a water hyacinth dominated state in 2006 to an alternative submerged macrophyte dominated stable state in 2008. It was concluded that this change could be attributed to: a stochastic flooding event in 2006; perturbation from integrated control measures implemented against water hyacinth; and low nitrate concentrations of the WMA. The lack of any substantial macroinvertebrate herbivory pressure or control measures implemented against Eurasian water-milfoil, compared to similar surveys conducted in the U.S.A. and its native range in Eurasia was shown to contribute to its dominance. Future successful integrated control programmes, including biological control against Eurasian water-milfoil, could provide the perturbation required to restore the ecosystem. However, without the reduction in nitrate concentration levels, water hyacinth will remain the dominant stable state of the rest of the Vaal River.
- Full Text:
- Authors: Fordham, Colin Justin
- Date: 2012
- Subjects: Water hyacinth -- Control -- South Africa , Aquatic weeds -- Control -- South Africa , Eurasian watermilfoil -- South Africa , Water quality management -- South Africa , Freshwater invertebrates -- Ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5767 , http://hdl.handle.net/10962/d1005455 , Water hyacinth -- Control -- South Africa , Aquatic weeds -- Control -- South Africa , Eurasian watermilfoil -- South Africa , Water quality management -- South Africa , Freshwater invertebrates -- Ecology -- South Africa
- Description: The majority of South Africa’s fresh water (lotic and lentic), is eutrophic and this has resulted in water hyacinth, Eichhornia crassipes (C.Mart.) Solms. (Pontederiaceae) becoming South Africa’s most damaging aquatic macrophyte. Recently however, concerns have also been voiced over the presence of highly invasive submerged macrophyte species, such as Eurasian water-milfoil, Myriophyllum spicatum L. (Haloragaceae) in the Vaal River. Interaction studies between floating and submerged macrophytes have shown that floating macrophyte dominance restricts light penetration into the water column shading out submerged macrophytes while submerged macrophyte dominance reduces nutrient availability in the water column limiting floating macrophyte growth. This cycle ensures that these species cannot coexist in the same habitat for extended periods of time. The aims of this thesis were to: 1. Investigate changes in the historical and current macrophyte dominance in the Vaal River 2. Determine whether these changes could be attributed to stochastic events, such as floods and herbicide control measures. 3. The physio-chemical conditions of the water column, and whether pressure from herbivory by macroinvertebrates had possibly influenced Eurasian water-milfoil’s ability to dominate. Spatial and temporal analysis of satellite imagery revealed that water hyacinth and submerged macrophyte species dominated different regions of the study area over different periods of time from 2006 to 2010. This was significantly correlated with nitrate concentrations of the water column. One of the lower Vaal River Water Management Areas (WMA) had changed from a water hyacinth dominated state in 2006 to an alternative submerged macrophyte dominated stable state in 2008. It was concluded that this change could be attributed to: a stochastic flooding event in 2006; perturbation from integrated control measures implemented against water hyacinth; and low nitrate concentrations of the WMA. The lack of any substantial macroinvertebrate herbivory pressure or control measures implemented against Eurasian water-milfoil, compared to similar surveys conducted in the U.S.A. and its native range in Eurasia was shown to contribute to its dominance. Future successful integrated control programmes, including biological control against Eurasian water-milfoil, could provide the perturbation required to restore the ecosystem. However, without the reduction in nitrate concentration levels, water hyacinth will remain the dominant stable state of the rest of the Vaal River.
- Full Text:
A structural and functional specification of a SCIM for service interaction management and personalisation in the IMS
- Authors: Tsietsi, Mosiuoa Jeremia
- Date: 2012
- Subjects: Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4606 , http://hdl.handle.net/10962/d1004864 , Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Description: The Internet Protocol Multimedia Subsystem (IMS) is a component of the 3G mobile network that has been specified by standards development organisations such as the 3GPP (3rd Generation Partnership Project) and ETSI (European Telecommunication Standards Institute). IMS seeks to guarantee that the telecommunication network of the future provides subscribers with seamless access to services across disparate networks. In order to achieve this, it defines a service architecture that hosts application servers that provide subscribers with value added services. Typically, an application server bundles all the functionality it needs to execute the services it delivers, however this view is currently being challenged. It is now thought that services should be synthesised from simple building blocks called service capabilities. This decomposition would facilitate the re-use of service capabilities across multiple services and would support the creation of new services that could not have originally been conceived. The shift from monolithic services to those built from service capabilities poses a challenge to the current service model in IMS. To accommodate this, the 3GPP has defined an entity known as a service capability interaction manager (SCIM) that would be responsible for managing the interactions between service capabilities in order to realise complex services. Some of these interactions could potentially lead to undesirable results, which the SCIM must work to avoid. As an added requirement, it is believed that the network should allow policies to be applied to network services which the SCIM should be responsible for enforcing. At the time of writing, the functional and structural architecture of the SCIM has not yet been standardised. This thesis explores the current serv ice architecture of the IMS in detail. Proposals that address the structure and functions of the SCIM are carefully compared and contrasted. This investigation leads to the presentation of key aspects of the SCIM, and provides solutions that explain how it should interact with service capabilities, manage undesirable interactions and factor user and network operator policies into its execution model. A modified design of the IMS service layer that embeds the SCIM is subsequently presented and described. The design uses existing IMS protocols and requires no change in the behaviour of the standard IMS entities. In order to develop a testbed for experimental verification of the design, the identification of suitable software platforms was required. This thesis presents some of the most popular platforms currently used by developers such as the Open IMS Core and OpenSER, as well as an open source, Java-based, multimedia communication platform called Mobicents. As a precursor to the development of the SCIM, a converged multimedia service is presented that describes how a video streaming application that is leveraged by a web portal was implemented for an IMS testbed using Mobicents components. The Mobicents SIP Servlets container was subsequently used to model an initial prototype of the SCIM, using a mUlti-component telephony service to illustrate the proposed service execution model. The design focuses on SIP-based services only, but should also work for other types of IMS application servers as well.
- Full Text:
- Authors: Tsietsi, Mosiuoa Jeremia
- Date: 2012
- Subjects: Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4606 , http://hdl.handle.net/10962/d1004864 , Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Description: The Internet Protocol Multimedia Subsystem (IMS) is a component of the 3G mobile network that has been specified by standards development organisations such as the 3GPP (3rd Generation Partnership Project) and ETSI (European Telecommunication Standards Institute). IMS seeks to guarantee that the telecommunication network of the future provides subscribers with seamless access to services across disparate networks. In order to achieve this, it defines a service architecture that hosts application servers that provide subscribers with value added services. Typically, an application server bundles all the functionality it needs to execute the services it delivers, however this view is currently being challenged. It is now thought that services should be synthesised from simple building blocks called service capabilities. This decomposition would facilitate the re-use of service capabilities across multiple services and would support the creation of new services that could not have originally been conceived. The shift from monolithic services to those built from service capabilities poses a challenge to the current service model in IMS. To accommodate this, the 3GPP has defined an entity known as a service capability interaction manager (SCIM) that would be responsible for managing the interactions between service capabilities in order to realise complex services. Some of these interactions could potentially lead to undesirable results, which the SCIM must work to avoid. As an added requirement, it is believed that the network should allow policies to be applied to network services which the SCIM should be responsible for enforcing. At the time of writing, the functional and structural architecture of the SCIM has not yet been standardised. This thesis explores the current serv ice architecture of the IMS in detail. Proposals that address the structure and functions of the SCIM are carefully compared and contrasted. This investigation leads to the presentation of key aspects of the SCIM, and provides solutions that explain how it should interact with service capabilities, manage undesirable interactions and factor user and network operator policies into its execution model. A modified design of the IMS service layer that embeds the SCIM is subsequently presented and described. The design uses existing IMS protocols and requires no change in the behaviour of the standard IMS entities. In order to develop a testbed for experimental verification of the design, the identification of suitable software platforms was required. This thesis presents some of the most popular platforms currently used by developers such as the Open IMS Core and OpenSER, as well as an open source, Java-based, multimedia communication platform called Mobicents. As a precursor to the development of the SCIM, a converged multimedia service is presented that describes how a video streaming application that is leveraged by a web portal was implemented for an IMS testbed using Mobicents components. The Mobicents SIP Servlets container was subsequently used to model an initial prototype of the SCIM, using a mUlti-component telephony service to illustrate the proposed service execution model. The design focuses on SIP-based services only, but should also work for other types of IMS application servers as well.
- Full Text:
A study of four-dimensional oscillator groups and the associated left-invariant control affine systems
- Authors: Biggs, Rory
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164941 , vital:41186
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Department of Mathematics, 2012
- Full Text:
- Authors: Biggs, Rory
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164941 , vital:41186
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Department of Mathematics, 2012
- Full Text:
A study on the morphology of thin copper films on para-aramid yarns and their influence on the yarn’s electro-conductive and mechanical properties
- Schwarz, Anne, Hakuzimana, Jean, Westbroek, Philippe, Mey, Gilbert De, Priniotakis, Georgios, Nyokong, Tebello, Langenhove, Lieva Van
- Authors: Schwarz, Anne , Hakuzimana, Jean , Westbroek, Philippe , Mey, Gilbert De , Priniotakis, Georgios , Nyokong, Tebello , Langenhove, Lieva Van
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243487 , vital:51157 , xlink:href="https://doi.org/10.1177/0040517511431291"
- Description: The latest technological advances in new materials and devices enabled wearable systems to be created by utilizing textile solutions. These solutions require electro-conductive yarns as a basic component. Although the production of electroconductive yarn is widely reported, research is still necessary to characterize them to advance their electro-conductive and mechanical properties. Hence, we served this need and characterized copper-coated para-aramid yarns produced by an in-house developed electroless deposition method. In this paper we present our investigation on the yarn’s copper layer characteristics after deposition. Furthermore, we looked, in depth, at the yarn’s electro-conductive properties before and after washing as well as their mechanical properties before and after copper deposition. We found a dependency of the copper layer morphology on its deposition time. This is directly correlated to the resulting layer thickness and hence to the yarn’s electro-conductive properties, demonstrating the autocatalytic nature of the coating process. Above that, the electro-conductive properties of the coated yarn linearly decrease with washing cycles. Furthermore, the copper coating impairs the yarn’s mechanical properties decreasing its specific stress at break by 30%.
- Full Text:
- Authors: Schwarz, Anne , Hakuzimana, Jean , Westbroek, Philippe , Mey, Gilbert De , Priniotakis, Georgios , Nyokong, Tebello , Langenhove, Lieva Van
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243487 , vital:51157 , xlink:href="https://doi.org/10.1177/0040517511431291"
- Description: The latest technological advances in new materials and devices enabled wearable systems to be created by utilizing textile solutions. These solutions require electro-conductive yarns as a basic component. Although the production of electroconductive yarn is widely reported, research is still necessary to characterize them to advance their electro-conductive and mechanical properties. Hence, we served this need and characterized copper-coated para-aramid yarns produced by an in-house developed electroless deposition method. In this paper we present our investigation on the yarn’s copper layer characteristics after deposition. Furthermore, we looked, in depth, at the yarn’s electro-conductive properties before and after washing as well as their mechanical properties before and after copper deposition. We found a dependency of the copper layer morphology on its deposition time. This is directly correlated to the resulting layer thickness and hence to the yarn’s electro-conductive properties, demonstrating the autocatalytic nature of the coating process. Above that, the electro-conductive properties of the coated yarn linearly decrease with washing cycles. Furthermore, the copper coating impairs the yarn’s mechanical properties decreasing its specific stress at break by 30%.
- Full Text:
A systematic revision of selected genera of afrotropical curtonotidae (Diptera: schizophora: ephydroidea) : a phylogenetic approach
- Authors: Kirk-Spriggs, Ashley H
- Date: 2012
- Subjects: Curtonotidae -- Research Diptera -- Research Flies -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5627 , http://hdl.handle.net/10962/d1004747
- Description: The first comprehensive phylogeny of the family Curtonotidae is presented based on molecular markers and morphology. This enabled assessment of evolutionary relatedness, species radiation and zoogeography. A revised classification of the world fauna of the family, based on the results of this study is outlined. Nomenclatural acts flowing from these analyses include: the recognition three new Afrotropical species of Axinota van der Wulp; four new species of a new genus, Tigrisomyia Kirk-Spriggs; and nineteen new species of Curtonotum (six Madagascan and thirteen African). Ten informal species-groups of Curtonotum are recognised. Identification keys are provided for the Afrotropical species of these genera and errors in previous interpretations and designation of type specimens are resolved. Species distributions are mapped and interpreted and discussion is made of the historical biogeographical significance of these distributions.
- Full Text:
- Authors: Kirk-Spriggs, Ashley H
- Date: 2012
- Subjects: Curtonotidae -- Research Diptera -- Research Flies -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5627 , http://hdl.handle.net/10962/d1004747
- Description: The first comprehensive phylogeny of the family Curtonotidae is presented based on molecular markers and morphology. This enabled assessment of evolutionary relatedness, species radiation and zoogeography. A revised classification of the world fauna of the family, based on the results of this study is outlined. Nomenclatural acts flowing from these analyses include: the recognition three new Afrotropical species of Axinota van der Wulp; four new species of a new genus, Tigrisomyia Kirk-Spriggs; and nineteen new species of Curtonotum (six Madagascan and thirteen African). Ten informal species-groups of Curtonotum are recognised. Identification keys are provided for the Afrotropical species of these genera and errors in previous interpretations and designation of type specimens are resolved. Species distributions are mapped and interpreted and discussion is made of the historical biogeographical significance of these distributions.
- Full Text:
Adolescents' knowledge about abortion and emergency contraception a survey study
- Authors: Seutlwadi, Lebogang
- Date: 2012
- Subjects: Birth control -- Social aspects -- South Africa -- Buffalo City Emergency contraceptives -- Social aspects -- South Africa -- Buffalo City Reproductive rights -- South Africa Teenage pregnancy -- Social aspects -- South Africa -- Buffalo City Teenage pregnancy -- Psychological aspects -- South Africa -- Buffalo City Abortion -- Social aspects -- South Africa -- Buffalo City Abortion -- Health aspects -- South Africa -- Buffalo City Abortion -- Psychological aspects -- South Africa -- Buffalo City Teenagers -- Sexual behavior -- South Africa -- Buffalo City Sex instruction for teenagers -- South Africa -- Buffalo City Health education -- South Africa -- Buffalo City
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3052 , http://hdl.handle.net/10962/d1002561
- Description: Adolescents have become focal points of discussions and debates regarding sexuality and reproductive health matters. However, little research has been done particularly in South Africa to examine their knowledge concerning abortion and emergency contraception. Research indicates that a substantial proportion of adolescent pregnancies are unintended or unwanted. Abortion and emergency contraception are both time-sensitive services. Thus having accurate and comprehensive knowledge about both abortion and emergency contraception is pivotal, in the case of unintended or unwanted pregnancy or when engaging in unprotected sex or experiencing contraceptive failure that could lead to pregnancy. The 1994 International Conference on Population and Development (ICPD) defined reproductive health rights for both men and women as the right to "decide freely and responsibly the number, spacing and timing of their children and to have the information and means to do so" (p. 60). That is, men and women should "have the right to make decisions concerning their reproduction free of discrimination, violence and coercion" (ICPD, 1994, p.60). Based on these definitions, it is rather evident that comprehensive and accurate knowledge are at the core of one's ability to make an informed consent. This is confirmed by Adler's (1992, p. 289) definition of informed consent or choice "a) access to sufficient information b) understanding the information c) competence to evaluate potential consequences d) freedom to make a choice and e) the ability to make and express that choice". It is from this framework that this study emerged. The aim of this study was to examine adolescents' knowledge concerning abortion and emergency contraception. The participants were Grade 11 learners between the ages of 15-24 years from five different schools in the Buffalo City Municipality. A sample of 514 was achieved. Data were analysed using descriptive cross-tabulation, chi-square and qualitative methods where appropriate. The results revealed that most of the participants did not have sufficient accurate knowledge concerning the Choice on Termination of Pregnancy Act, consequences of legal abortion and emergency contraceptive pills to make informed decisions. Furthermore, data also revealed that the participants' schools playa role in their sexual activity, their knowledge about the Choice on Termination of Pregnancy Act and about emergency contraceptive pills. Although this method made it feasible for the researcher to make general assumptions, non-responses were one of the limitations of the study. Similar research in various municipalities/cities in and outside the Eastern Cape is recommended so as to increase further awareness concerning the level of knowledge that adolescents have about contraceptive pills particularly emergency contraceptive pills, the Choice on Termination of Pregnancy Act and abortion in general.
- Full Text:
- Authors: Seutlwadi, Lebogang
- Date: 2012
- Subjects: Birth control -- Social aspects -- South Africa -- Buffalo City Emergency contraceptives -- Social aspects -- South Africa -- Buffalo City Reproductive rights -- South Africa Teenage pregnancy -- Social aspects -- South Africa -- Buffalo City Teenage pregnancy -- Psychological aspects -- South Africa -- Buffalo City Abortion -- Social aspects -- South Africa -- Buffalo City Abortion -- Health aspects -- South Africa -- Buffalo City Abortion -- Psychological aspects -- South Africa -- Buffalo City Teenagers -- Sexual behavior -- South Africa -- Buffalo City Sex instruction for teenagers -- South Africa -- Buffalo City Health education -- South Africa -- Buffalo City
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3052 , http://hdl.handle.net/10962/d1002561
- Description: Adolescents have become focal points of discussions and debates regarding sexuality and reproductive health matters. However, little research has been done particularly in South Africa to examine their knowledge concerning abortion and emergency contraception. Research indicates that a substantial proportion of adolescent pregnancies are unintended or unwanted. Abortion and emergency contraception are both time-sensitive services. Thus having accurate and comprehensive knowledge about both abortion and emergency contraception is pivotal, in the case of unintended or unwanted pregnancy or when engaging in unprotected sex or experiencing contraceptive failure that could lead to pregnancy. The 1994 International Conference on Population and Development (ICPD) defined reproductive health rights for both men and women as the right to "decide freely and responsibly the number, spacing and timing of their children and to have the information and means to do so" (p. 60). That is, men and women should "have the right to make decisions concerning their reproduction free of discrimination, violence and coercion" (ICPD, 1994, p.60). Based on these definitions, it is rather evident that comprehensive and accurate knowledge are at the core of one's ability to make an informed consent. This is confirmed by Adler's (1992, p. 289) definition of informed consent or choice "a) access to sufficient information b) understanding the information c) competence to evaluate potential consequences d) freedom to make a choice and e) the ability to make and express that choice". It is from this framework that this study emerged. The aim of this study was to examine adolescents' knowledge concerning abortion and emergency contraception. The participants were Grade 11 learners between the ages of 15-24 years from five different schools in the Buffalo City Municipality. A sample of 514 was achieved. Data were analysed using descriptive cross-tabulation, chi-square and qualitative methods where appropriate. The results revealed that most of the participants did not have sufficient accurate knowledge concerning the Choice on Termination of Pregnancy Act, consequences of legal abortion and emergency contraceptive pills to make informed decisions. Furthermore, data also revealed that the participants' schools playa role in their sexual activity, their knowledge about the Choice on Termination of Pregnancy Act and about emergency contraceptive pills. Although this method made it feasible for the researcher to make general assumptions, non-responses were one of the limitations of the study. Similar research in various municipalities/cities in and outside the Eastern Cape is recommended so as to increase further awareness concerning the level of knowledge that adolescents have about contraceptive pills particularly emergency contraceptive pills, the Choice on Termination of Pregnancy Act and abortion in general.
- Full Text:
Amplified fragment length polymorphism confirms reciprocal monophyly in Chrysomya putoria and Chrysomya chloropyga: a correction of reported shared mtDNA haplotypes
- Picard, C J, Villet, Martin H, Wells, J D
- Authors: Picard, C J , Villet, Martin H , Wells, J D
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441760 , vital:73914 , DOI:10.4236/jcdsa.2012.22018
- Description: Reinvestigation of mitochondrial haplotypes previously reported to be shared between the Afrotropical blowflies Chrysomya putoria Weidemann and Chrysomya chloropyga Weidemann (Diptera: Calliphoridae) revealed an error resulting from the misidentification of specimens. Preliminary amplified fragment length polymorphism (AFLP) analysis of the original and additional individuals again failed to find reciprocal monophyly, leading to a re‐examination of the specimens for diagnostic male genitalic characters that were first described following the earlier study. Four of the original study specimens were found to have been misidentified, and definitive analysis of both mtDNA and AFLP genotypes using phylogenetic analysis and genetic assignment showed that each species was indeed reciprocally monophyletic. In addition to correcting the earlier error, this study illustrates how AFLP analysis can be used for efficient and effective specimen identification through both phylogenetic analysis and genetic assignment, and suggests that the latter method has special advantages for identification when no conspecific specimens are represented in the reference database.
- Full Text:
- Authors: Picard, C J , Villet, Martin H , Wells, J D
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441760 , vital:73914 , DOI:10.4236/jcdsa.2012.22018
- Description: Reinvestigation of mitochondrial haplotypes previously reported to be shared between the Afrotropical blowflies Chrysomya putoria Weidemann and Chrysomya chloropyga Weidemann (Diptera: Calliphoridae) revealed an error resulting from the misidentification of specimens. Preliminary amplified fragment length polymorphism (AFLP) analysis of the original and additional individuals again failed to find reciprocal monophyly, leading to a re‐examination of the specimens for diagnostic male genitalic characters that were first described following the earlier study. Four of the original study specimens were found to have been misidentified, and definitive analysis of both mtDNA and AFLP genotypes using phylogenetic analysis and genetic assignment showed that each species was indeed reciprocally monophyletic. In addition to correcting the earlier error, this study illustrates how AFLP analysis can be used for efficient and effective specimen identification through both phylogenetic analysis and genetic assignment, and suggests that the latter method has special advantages for identification when no conspecific specimens are represented in the reference database.
- Full Text:
An Analysis and Implementation of Methods for High Speed Lexical Classification of Malicious URLs
- Egan, Shaun P, Irwin, Barry V W
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429757 , vital:72637 , https://digifors.cs.up.ac.za/issa/2012/Proceedings/Research/58_ResearchInProgress.pdf
- Description: Several authors have put forward methods of using Artificial Neural Networks (ANN) to classify URLs as malicious or benign by using lexical features of those URLs. These methods have been compared to other methods of classification, such as blacklisting and spam filtering, and have been found to be as accurate. Early attempts proved to be as highly accurate. Fully featured classifications use lexical features as well as lookups to classify URLs and include (but are not limited to) blacklists, spam filters and reputation services. These classifiers are based on the Online Perceptron Model, using a single neuron as a linear combiner and used lexical features that rely on the presence (or lack thereof) of words belonging to a bag-of-words. Several obfuscation resistant features are also used to increase the positive classification rate of these perceptrons. Examples of these include URL length, number of directory traversals and length of arguments passed to the file within the URL. In this paper we describe how we implement the online perceptron model and methods that we used to try to increase the accuracy of this model through the use of hidden layers and training cost validation. We discuss our results in relation to those of other papers, as well as other analysis performed on the training data and the neural networks themselves to best understand why they are so effective. Also described will be the proposed model for developing these Neural Networks, how to implement them in the real world through the use of browser extensions, proxy plugins and spam filters for mail servers, and our current implementation. Finally, work that is still in progress will be described. This work includes other methods of increasing accuracy through the use of modern training techniques and testing in a real world environment.
- Full Text:
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429757 , vital:72637 , https://digifors.cs.up.ac.za/issa/2012/Proceedings/Research/58_ResearchInProgress.pdf
- Description: Several authors have put forward methods of using Artificial Neural Networks (ANN) to classify URLs as malicious or benign by using lexical features of those URLs. These methods have been compared to other methods of classification, such as blacklisting and spam filtering, and have been found to be as accurate. Early attempts proved to be as highly accurate. Fully featured classifications use lexical features as well as lookups to classify URLs and include (but are not limited to) blacklists, spam filters and reputation services. These classifiers are based on the Online Perceptron Model, using a single neuron as a linear combiner and used lexical features that rely on the presence (or lack thereof) of words belonging to a bag-of-words. Several obfuscation resistant features are also used to increase the positive classification rate of these perceptrons. Examples of these include URL length, number of directory traversals and length of arguments passed to the file within the URL. In this paper we describe how we implement the online perceptron model and methods that we used to try to increase the accuracy of this model through the use of hidden layers and training cost validation. We discuss our results in relation to those of other papers, as well as other analysis performed on the training data and the neural networks themselves to best understand why they are so effective. Also described will be the proposed model for developing these Neural Networks, how to implement them in the real world through the use of browser extensions, proxy plugins and spam filters for mail servers, and our current implementation. Finally, work that is still in progress will be described. This work includes other methods of increasing accuracy through the use of modern training techniques and testing in a real world environment.
- Full Text:
An analysis of ionospheric response to geomagnetic disturbances over South Africa and Antarctica
- Authors: Ngwira, Chigomezyo Mudala
- Date: 2012
- Subjects: Geomagnetism -- South Africa , Geomagnetism -- Antarctica , Ionospheric storms -- South Africa , Ionospheric storms -- Antarctica
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5534 , http://hdl.handle.net/10962/d1012957
- Description: The ionosphere is of practical importance for satellite-based communication and navigation systems due to its variable refractive nature which affects the propagation of trans-ionospheric radio signals. This thesis reports on the first attempt to investigate the mechanisms responsible for the generation of positive ionospheric storm effects over mid-latitude South Africa. The storm response on 15 May 2005 was associated with equatorward neutral winds and the passage of travelling ionospheric disturbances (TIDs). The two TIDs reported in this thesis propagated with average velocities of ∼438 m/s and ∼515 m/s respectively. The velocity of the first TID (i.e. 438 m/s) is consistent with the velocities calculated in other studies for the same storm event. In a second case study, the positive storm enhancement on both 25 and 27 July 2004 lasted for more than 7 hours, and were classified as long-duration positive ionospheric storm effects. It has been suggested that the long-duration positive storm effects could have been caused by large-scale thermospheric wind circulation and enhanced equatorward neutral winds. These processes were in turn most likely to have been driven by enhanced and sustained energy input in the high-latitude ionosphere due to Joule heating and particle energy injection. This is evident by the prolonged high-level geomagnetic activity on both 25 and 27 July. This thesis also reports on the phase scintillation investigation at the South African Antarctic polar research station during solar minimum conditions. The multi-instrument approach that was used shows that the scintillation events were associated with auroral electron precipitation and that substorms play an essential role in the production of scintillation in the high latitudes. Furthermore, the investigation reveals that external energy injection into the ionosphere is necessary for the development of high-latitude irregularities which produce scintillation. Finally, this thesis highlights inadequate data resources as one of the major shortcomings to be addressed in order to fully understand and distinguish between the various ionospheric storm drivers over the Southern Africa mid-latitude region. The results presented in this thesis on the ionospheric response during geomagnetic storms provide essential information to direct further investigation aimed at developing this emerging field of study in South Africa.
- Full Text:
- Authors: Ngwira, Chigomezyo Mudala
- Date: 2012
- Subjects: Geomagnetism -- South Africa , Geomagnetism -- Antarctica , Ionospheric storms -- South Africa , Ionospheric storms -- Antarctica
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5534 , http://hdl.handle.net/10962/d1012957
- Description: The ionosphere is of practical importance for satellite-based communication and navigation systems due to its variable refractive nature which affects the propagation of trans-ionospheric radio signals. This thesis reports on the first attempt to investigate the mechanisms responsible for the generation of positive ionospheric storm effects over mid-latitude South Africa. The storm response on 15 May 2005 was associated with equatorward neutral winds and the passage of travelling ionospheric disturbances (TIDs). The two TIDs reported in this thesis propagated with average velocities of ∼438 m/s and ∼515 m/s respectively. The velocity of the first TID (i.e. 438 m/s) is consistent with the velocities calculated in other studies for the same storm event. In a second case study, the positive storm enhancement on both 25 and 27 July 2004 lasted for more than 7 hours, and were classified as long-duration positive ionospheric storm effects. It has been suggested that the long-duration positive storm effects could have been caused by large-scale thermospheric wind circulation and enhanced equatorward neutral winds. These processes were in turn most likely to have been driven by enhanced and sustained energy input in the high-latitude ionosphere due to Joule heating and particle energy injection. This is evident by the prolonged high-level geomagnetic activity on both 25 and 27 July. This thesis also reports on the phase scintillation investigation at the South African Antarctic polar research station during solar minimum conditions. The multi-instrument approach that was used shows that the scintillation events were associated with auroral electron precipitation and that substorms play an essential role in the production of scintillation in the high latitudes. Furthermore, the investigation reveals that external energy injection into the ionosphere is necessary for the development of high-latitude irregularities which produce scintillation. Finally, this thesis highlights inadequate data resources as one of the major shortcomings to be addressed in order to fully understand and distinguish between the various ionospheric storm drivers over the Southern Africa mid-latitude region. The results presented in this thesis on the ionospheric response during geomagnetic storms provide essential information to direct further investigation aimed at developing this emerging field of study in South Africa.
- Full Text:
An analysis of pacing and sequencing of reading instruction in three grade 1 classrooms where isiXhosa is the language of learning and teaching
- Authors: Masola, Athambile
- Date: 2012
- Subjects: Reading (Elementary) -- Study and teaching -- Foreign speakers -- Research -- South Africa Literacy -- Education (Primary) -- Research -- South Africa English language -- Study and teaching -- South Africa -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1420 , http://hdl.handle.net/10962/d1003301
- Description: Reading development in the Foundation Phase (FP) is central to children’s success as they progress through school. However, evaluations in South Africa such as the Annual National Assessments (ANAs) and the Progress in International Reading Literacy Study (PIRLS) (2006) show that reading achievement in the Foundation Phase is low, especially for children learning with African languages as their home language. This thesis examines pacing and sequencing in three Grade 1 literacy classes where isiXhosa is the language of learning and teaching (LOLT). The research took the form of a case study, focusing on the teachers’ classroom practice and how they understand their practice. Documents related to reading development in the Foundation Phase are analysed with regard to pacing and sequencing, examining how the curriculum frames literacy for teachers in the Foundation Phase. The teachers’ understanding in relation to their social context is also an important part of this research. In the thesis the way in which the teachers sequence and pace learning is analysed, drawing on Bernstein’s notions of internal and external framing, and Bourdieu’s notion of the habitus. The intended curriculum and the implemented curriculum are then compared. The results confirm that in low socio‐economic status (SES) schools, the level of poverty has an impact on teaching practice. The results also show that pacing and sequencing are reliant on the degree of planning amongst teachers. The level of development amongst learners also plays a role in how teachers organise their practice in order to differentiate the teaching of reading for all learners. The understanding that teachers have about their teaching practice are layered and influenced by their experiences, history and memories as teachers. The thesis concludes that there is a need to develop teachers’ understanding of planning and organising the teaching of reading, especially when the learners are from poor communities and do not get support in the home. In order for teachers to improve their practice, it is important for them to have the opportunity to reflect on and understand their practice.
- Full Text:
- Authors: Masola, Athambile
- Date: 2012
- Subjects: Reading (Elementary) -- Study and teaching -- Foreign speakers -- Research -- South Africa Literacy -- Education (Primary) -- Research -- South Africa English language -- Study and teaching -- South Africa -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1420 , http://hdl.handle.net/10962/d1003301
- Description: Reading development in the Foundation Phase (FP) is central to children’s success as they progress through school. However, evaluations in South Africa such as the Annual National Assessments (ANAs) and the Progress in International Reading Literacy Study (PIRLS) (2006) show that reading achievement in the Foundation Phase is low, especially for children learning with African languages as their home language. This thesis examines pacing and sequencing in three Grade 1 literacy classes where isiXhosa is the language of learning and teaching (LOLT). The research took the form of a case study, focusing on the teachers’ classroom practice and how they understand their practice. Documents related to reading development in the Foundation Phase are analysed with regard to pacing and sequencing, examining how the curriculum frames literacy for teachers in the Foundation Phase. The teachers’ understanding in relation to their social context is also an important part of this research. In the thesis the way in which the teachers sequence and pace learning is analysed, drawing on Bernstein’s notions of internal and external framing, and Bourdieu’s notion of the habitus. The intended curriculum and the implemented curriculum are then compared. The results confirm that in low socio‐economic status (SES) schools, the level of poverty has an impact on teaching practice. The results also show that pacing and sequencing are reliant on the degree of planning amongst teachers. The level of development amongst learners also plays a role in how teachers organise their practice in order to differentiate the teaching of reading for all learners. The understanding that teachers have about their teaching practice are layered and influenced by their experiences, history and memories as teachers. The thesis concludes that there is a need to develop teachers’ understanding of planning and organising the teaching of reading, especially when the learners are from poor communities and do not get support in the home. In order for teachers to improve their practice, it is important for them to have the opportunity to reflect on and understand their practice.
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An analysis of the determinants and recent decline of private savings in South Africa
- Authors: Linde, Kathryn Leigh
- Date: 2012
- Subjects: Saving and investment -- Research -- South Africa Finance, Personal -- Research -- South Africa Corporations -- Finance -- Research -- South Africa Economic development -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1007 , http://hdl.handle.net/10962/d1002742
- Description: Low domestic saving rates make South Africa highly dependent on foreign capital inflows to fund higher investment levels. These inflows are highly volatile and may prove to be unsustainable in the long-run. This study analyses the determinants of private saving in South Africa, with specific reference to the decline in private saving rates that occurred at a time of higher economic growth prior to the 2008 global financial crisis. The Johansen cointegration method is used to estimate separate vector error correction models (VECM) in order to assess the effect of specific variables on both corporate and household saving. The results obtained that are common to both corporate and household savmg show that the govemment budget balance negatively impacts private saving rates though the offset is less than one. The real prime overdraft rate positively impacts private saving, although the result is small . The impact of real Gross Domestic Product (GDP) is positive. In recent years, however, private saving rates fell alongside higher economic growth, which may reflect a structural change in corporate saving behaviour. The results distinct to the corporate saving model show that commodity prices have a negative impact on corporate saving. This does not conform to a priori expectations, but is supported by the behaviour of these two variables in recent years. Foreign savings were found to impact negatively on corporate saving. This result is important, since the dependence of the South African economy on foreign capital inflows to fund higher investment levels is reflected by high current account deficits during recent periods of economic growth. Evidence of financial liberalization negatively impacting on private saving in South Africa due to the removal of borrowing constraints was found. A negative relationship was found between corporate saving and investment demonstrating that corporations have reduced levels of retained eamings for funding investment expenditures. The results distinct to the household saving model provide evidence of a negative wealth effect in South Africa, with rising housing wealth found to increase consumption. Evidence of households "piercing the corporate veil" in South Africa was found. Therefore, households view corporate saving behaviour as essentially being conducted on their behalf. This finding and the finding that the offset between the budget deficit and private saving is less than one suggest that counter-cyclical fiscal policy will be an important policy response for achieving higher domestic saving rates in South Africa.
- Full Text:
- Authors: Linde, Kathryn Leigh
- Date: 2012
- Subjects: Saving and investment -- Research -- South Africa Finance, Personal -- Research -- South Africa Corporations -- Finance -- Research -- South Africa Economic development -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1007 , http://hdl.handle.net/10962/d1002742
- Description: Low domestic saving rates make South Africa highly dependent on foreign capital inflows to fund higher investment levels. These inflows are highly volatile and may prove to be unsustainable in the long-run. This study analyses the determinants of private saving in South Africa, with specific reference to the decline in private saving rates that occurred at a time of higher economic growth prior to the 2008 global financial crisis. The Johansen cointegration method is used to estimate separate vector error correction models (VECM) in order to assess the effect of specific variables on both corporate and household saving. The results obtained that are common to both corporate and household savmg show that the govemment budget balance negatively impacts private saving rates though the offset is less than one. The real prime overdraft rate positively impacts private saving, although the result is small . The impact of real Gross Domestic Product (GDP) is positive. In recent years, however, private saving rates fell alongside higher economic growth, which may reflect a structural change in corporate saving behaviour. The results distinct to the corporate saving model show that commodity prices have a negative impact on corporate saving. This does not conform to a priori expectations, but is supported by the behaviour of these two variables in recent years. Foreign savings were found to impact negatively on corporate saving. This result is important, since the dependence of the South African economy on foreign capital inflows to fund higher investment levels is reflected by high current account deficits during recent periods of economic growth. Evidence of financial liberalization negatively impacting on private saving in South Africa due to the removal of borrowing constraints was found. A negative relationship was found between corporate saving and investment demonstrating that corporations have reduced levels of retained eamings for funding investment expenditures. The results distinct to the household saving model provide evidence of a negative wealth effect in South Africa, with rising housing wealth found to increase consumption. Evidence of households "piercing the corporate veil" in South Africa was found. Therefore, households view corporate saving behaviour as essentially being conducted on their behalf. This finding and the finding that the offset between the budget deficit and private saving is less than one suggest that counter-cyclical fiscal policy will be an important policy response for achieving higher domestic saving rates in South Africa.
- Full Text: