Evaluating the IRI topside model for the South African region: An overview of the modelling techniques
- Sibanda, Patrick, McKinnell, Lee-Anne
- Authors: Sibanda, Patrick , McKinnell, Lee-Anne
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6810 , http://hdl.handle.net/10962/d1004303
- Description: The representation of the topside ionosphere (the region above the F2 peak) is critical because of the limited experimental data available. Over the years, a wide range of models have been developed in an effort to represent the behaviour and the shape of the electron density (Ne) profile of the topside ionosphere. Various studies have been centred around calculating the vertical scale height (VSH) and have included (a) obtaining VSH from Global Positioning System (GPS) derived total electron content (TEC), (b) calculating the VSH from ground-based ionosonde measurements, (c) using topside sounder vertical Ne profiles to obtain the VSH. One or a combination of the topside profilers (Chapman function, exponential function, sech-squared (Epstein) function, and/or parabolic function) is then used to reconstruct the topside Ne profile. The different approaches and the modelling techniques are discussed with a view to identifying the most adequate approach to apply to the South African region’s topside modelling efforts. The IRI-2001 topside model is evaluated based on how well it reproduces measured topside profiles over the South African region. This study is a first step in the process of developing a South African topside ionosphere model.
- Full Text:
- Authors: Sibanda, Patrick , McKinnell, Lee-Anne
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6810 , http://hdl.handle.net/10962/d1004303
- Description: The representation of the topside ionosphere (the region above the F2 peak) is critical because of the limited experimental data available. Over the years, a wide range of models have been developed in an effort to represent the behaviour and the shape of the electron density (Ne) profile of the topside ionosphere. Various studies have been centred around calculating the vertical scale height (VSH) and have included (a) obtaining VSH from Global Positioning System (GPS) derived total electron content (TEC), (b) calculating the VSH from ground-based ionosonde measurements, (c) using topside sounder vertical Ne profiles to obtain the VSH. One or a combination of the topside profilers (Chapman function, exponential function, sech-squared (Epstein) function, and/or parabolic function) is then used to reconstruct the topside Ne profile. The different approaches and the modelling techniques are discussed with a view to identifying the most adequate approach to apply to the South African region’s topside modelling efforts. The IRI-2001 topside model is evaluated based on how well it reproduces measured topside profiles over the South African region. This study is a first step in the process of developing a South African topside ionosphere model.
- Full Text:
Evaluating uncertainty in water resources estimation in Southern Africa : a case study of South Africa
- Authors: Sawunyama, Tendai
- Date: 2009
- Subjects: Water supply -- South Africa , Water supply -- Africa, Southern , Hydrology -- South Africa , Hydrology -- Africa, Southern , Hydrologic models , Hydrology research -- South Africa , Hydrology research -- Africa, Southern , Rain and rainfall -- Mathematical models , Runoff -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6035 , http://hdl.handle.net/10962/d1006176
- Description: Hydrological models are widely used tools in water resources estimation, but they are simple representations of reality and are frequently based on inadequate input data and uncertainties in parameter values. Data observation networks are expensive to establish and maintain and often beyond the resources of most developing countries. Consequently, measurements are difficult to obtain and observation networks in many countries are shrinking, hence obtaining representative observations in space and time remains a challenge. This study presents some guidelines on the identification, quantification and reduction of sources of uncertainty in water resources estimation in southern Africa, a data scarce region. The analyses are based on example sub-basins drawn from South Africa and the application of the Pitman hydrological model. While it has always been recognised that estimates of water resources availability for the region are subject to possible errors, the quantification of these uncertainties has never been explicitly incorporated into the methods used in the region. The motivation for this study was therefore to contribute to the future development of a revised framework for water resources estimation that does include uncertainty. The focus was on uncertainties associated with climate input data, parameter estimation (and recognizing the uncertainty due model structure deficiencies) methods and water use data. In addition to variance based measures of uncertainty, this study also used a reservoir yield based statistic to evaluate model output uncertainty, which represents an integrated measure of flow regime variations and one that can be more easily understood by water resources managers. Through a sensitivity analysis approach, the results of the individual contribution of each source of uncertainty suggest regional differences and that clear statements about which source of uncertainty is likely to dominate are not generally possible. Parameter sensitivity analysis was used in identifying parameters which are important withinspecific sub-basins and therefore those to focus on in uncertainty analysis. The study used a simple framework for evaluating the combined contribution of uncertainty sources to model outputs that is consistent with the model limitations and data available, and that allows direct quantitative comparison between model outputs obtained by using different sources of information and methods within Spatial and Time Series Information Modelling (SPATSIM) software. The results from combining the sources of uncertainties showed that parameter uncertainty dominates the contribution to model output uncertainty. However, in some parts of the country especially those with complex topography, which tend to experience high rainfall spatial variability, rainfall uncertainty is equally dominant, while the contributions of evaporation and water use data uncertainty are relatively small. While the results of this study are encouraging, the weaknesses of the methods used to quantify uncertainty (especially subjectivity involved in evaluating parameter uncertainty) should not be neglected and require further evaluations. An effort to reduce data and parameter uncertainty shows that this can only be achieved if data access at appropriate scale and quality improves. Perhaps the focus should be on maintaining existing networks and concentrating research efforts on making the most out of the emerging data products derived from remote sensing platforms. While this study presents some initial guidelines for evaluating uncertainty in South Africa, there is need to overcome several constraints which are related to data availability and accuracy, the models used and the capacity or willingness to adopt new methods that incorporate uncertainty. The study has provided a starting point for the development of new approaches to modelling water resources in the region that include uncertain estimates.
- Full Text:
- Authors: Sawunyama, Tendai
- Date: 2009
- Subjects: Water supply -- South Africa , Water supply -- Africa, Southern , Hydrology -- South Africa , Hydrology -- Africa, Southern , Hydrologic models , Hydrology research -- South Africa , Hydrology research -- Africa, Southern , Rain and rainfall -- Mathematical models , Runoff -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6035 , http://hdl.handle.net/10962/d1006176
- Description: Hydrological models are widely used tools in water resources estimation, but they are simple representations of reality and are frequently based on inadequate input data and uncertainties in parameter values. Data observation networks are expensive to establish and maintain and often beyond the resources of most developing countries. Consequently, measurements are difficult to obtain and observation networks in many countries are shrinking, hence obtaining representative observations in space and time remains a challenge. This study presents some guidelines on the identification, quantification and reduction of sources of uncertainty in water resources estimation in southern Africa, a data scarce region. The analyses are based on example sub-basins drawn from South Africa and the application of the Pitman hydrological model. While it has always been recognised that estimates of water resources availability for the region are subject to possible errors, the quantification of these uncertainties has never been explicitly incorporated into the methods used in the region. The motivation for this study was therefore to contribute to the future development of a revised framework for water resources estimation that does include uncertainty. The focus was on uncertainties associated with climate input data, parameter estimation (and recognizing the uncertainty due model structure deficiencies) methods and water use data. In addition to variance based measures of uncertainty, this study also used a reservoir yield based statistic to evaluate model output uncertainty, which represents an integrated measure of flow regime variations and one that can be more easily understood by water resources managers. Through a sensitivity analysis approach, the results of the individual contribution of each source of uncertainty suggest regional differences and that clear statements about which source of uncertainty is likely to dominate are not generally possible. Parameter sensitivity analysis was used in identifying parameters which are important withinspecific sub-basins and therefore those to focus on in uncertainty analysis. The study used a simple framework for evaluating the combined contribution of uncertainty sources to model outputs that is consistent with the model limitations and data available, and that allows direct quantitative comparison between model outputs obtained by using different sources of information and methods within Spatial and Time Series Information Modelling (SPATSIM) software. The results from combining the sources of uncertainties showed that parameter uncertainty dominates the contribution to model output uncertainty. However, in some parts of the country especially those with complex topography, which tend to experience high rainfall spatial variability, rainfall uncertainty is equally dominant, while the contributions of evaporation and water use data uncertainty are relatively small. While the results of this study are encouraging, the weaknesses of the methods used to quantify uncertainty (especially subjectivity involved in evaluating parameter uncertainty) should not be neglected and require further evaluations. An effort to reduce data and parameter uncertainty shows that this can only be achieved if data access at appropriate scale and quality improves. Perhaps the focus should be on maintaining existing networks and concentrating research efforts on making the most out of the emerging data products derived from remote sensing platforms. While this study presents some initial guidelines for evaluating uncertainty in South Africa, there is need to overcome several constraints which are related to data availability and accuracy, the models used and the capacity or willingness to adopt new methods that incorporate uncertainty. The study has provided a starting point for the development of new approaches to modelling water resources in the region that include uncertain estimates.
- Full Text:
Evaluation of a plant-herbivore system in determining potential efficacy of a candidate biological control agent, cornops aquaticum for water hyacinth, eichhornia crassipes
- Authors: Bownes, Angela
- Date: 2009
- Subjects: Water hyacinth -- Control -- South Africa , Eichhornia crassipedes , Pontederiaceae , Grasshoppers , Biological pest control agents -- South Africa , Weeds -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5687 , http://hdl.handle.net/10962/d1005373
- Description: Water hyacinth, Eichhornia crassipes Mart. Solms-Laubach (Pontederiaceae), a freefloating aquatic macrophyte of Neotropical origin, was introduced into South Africa as an ornamental aquarium plant in the early 1900’s. By the 1970’s it had reached pest proportions in dams and rivers around the country. Due to the sustainability, cost efficiency and low environmental risk associated with biological control, this has been a widely used method in an attempt to reduce infestations to below the threshold where they cause economic and ecological damage. To date, five arthropod and one pathogen biocontrol agents have been introduced for the control of water hyacinth but their impact has been variable. It is believed that their efficacy is hampered by the presence of highly eutrophic systems in South Africa in which plant growth is prolific and the negative effects of herbivory are therefore mitigated. It is for these reasons that new, potentially more damaging biocontrol agents are being considered for release. The water hyacinth grasshopper, Cornops aquaticum Brüner (Orthoptera: Acrididae), which is native to South America and Mexico, was brought into quarantine in Pretoria, South Africa in 1995. Although the grasshopper was identified as one of the most damaging insects associated with water hyacinth in its native range, it has not been considered as a biocontrol agent for water hyacinth anywhere else in the world. After extensive host-range testing which revealed it to be safe for release, a release permit for this candidate agent was issued in 2007. However, host specificity testing is no longer considered to be the only important component of pre-release screening of candidate biocontrol agents. Investigating biological and ecological aspects of the plant-herbivore system that will assist in determination of potential establishment, efficacy and the ability to build up good populations in the recipient environment are some of the important factors. This thesis is a pre-release evaluation of C. aquaticum to determine whether it is sufficiently damaging to water hyacinth to warrant its release. It investigated interactions between the grasshopper and water hyacinth under a range of nutrient conditions found in South African water bodies as well as the impact of the grasshopper on the competitive performance of water hyacinth. Both plant growth rates and the response of water hyacinth to herbivory by the grasshopper were influenced by nutrient availability to the plants. The ability of water hyacinth to compensate for loss of tissue through herbivory was greater under eutrophic nutrient conditions. However, a negative linear relationship was found between grasshopper biomass and water hyacinth performance parameters such as biomass accumulation and leaf production, even under eutrophic conditions. Water hyacinth’s compensatory ability in terms of its potential to mitigate to detrimental effects of insect feeding was dependent on the amount of damage caused by herbivory by the grasshopper. Plant biomass and the competitive ability of water hyacinth in relation to another freefloating aquatic weed species were reduced by C. aquaticum under eutrophic nutrient conditions, in a short space of time. It was also found that grasshopper feeding and characteristics related to their population dynamics such as fecundity and survival were significantly influenced by water nutrient availability and that environmental nutrient availability will influence the control potential of this species should it be released in South Africa. Cornops aquaticum shows promise as a biocontrol agent for water hyacinth but additional factors that were not investigated in this study such as compatibility with the South African climate and the current water hyacinth biocontrol agents need to be combined with these data to make a decision on its release. Possible management options for this species if it is to be introduced into South Africa are discussed.
- Full Text:
- Authors: Bownes, Angela
- Date: 2009
- Subjects: Water hyacinth -- Control -- South Africa , Eichhornia crassipedes , Pontederiaceae , Grasshoppers , Biological pest control agents -- South Africa , Weeds -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5687 , http://hdl.handle.net/10962/d1005373
- Description: Water hyacinth, Eichhornia crassipes Mart. Solms-Laubach (Pontederiaceae), a freefloating aquatic macrophyte of Neotropical origin, was introduced into South Africa as an ornamental aquarium plant in the early 1900’s. By the 1970’s it had reached pest proportions in dams and rivers around the country. Due to the sustainability, cost efficiency and low environmental risk associated with biological control, this has been a widely used method in an attempt to reduce infestations to below the threshold where they cause economic and ecological damage. To date, five arthropod and one pathogen biocontrol agents have been introduced for the control of water hyacinth but their impact has been variable. It is believed that their efficacy is hampered by the presence of highly eutrophic systems in South Africa in which plant growth is prolific and the negative effects of herbivory are therefore mitigated. It is for these reasons that new, potentially more damaging biocontrol agents are being considered for release. The water hyacinth grasshopper, Cornops aquaticum Brüner (Orthoptera: Acrididae), which is native to South America and Mexico, was brought into quarantine in Pretoria, South Africa in 1995. Although the grasshopper was identified as one of the most damaging insects associated with water hyacinth in its native range, it has not been considered as a biocontrol agent for water hyacinth anywhere else in the world. After extensive host-range testing which revealed it to be safe for release, a release permit for this candidate agent was issued in 2007. However, host specificity testing is no longer considered to be the only important component of pre-release screening of candidate biocontrol agents. Investigating biological and ecological aspects of the plant-herbivore system that will assist in determination of potential establishment, efficacy and the ability to build up good populations in the recipient environment are some of the important factors. This thesis is a pre-release evaluation of C. aquaticum to determine whether it is sufficiently damaging to water hyacinth to warrant its release. It investigated interactions between the grasshopper and water hyacinth under a range of nutrient conditions found in South African water bodies as well as the impact of the grasshopper on the competitive performance of water hyacinth. Both plant growth rates and the response of water hyacinth to herbivory by the grasshopper were influenced by nutrient availability to the plants. The ability of water hyacinth to compensate for loss of tissue through herbivory was greater under eutrophic nutrient conditions. However, a negative linear relationship was found between grasshopper biomass and water hyacinth performance parameters such as biomass accumulation and leaf production, even under eutrophic conditions. Water hyacinth’s compensatory ability in terms of its potential to mitigate to detrimental effects of insect feeding was dependent on the amount of damage caused by herbivory by the grasshopper. Plant biomass and the competitive ability of water hyacinth in relation to another freefloating aquatic weed species were reduced by C. aquaticum under eutrophic nutrient conditions, in a short space of time. It was also found that grasshopper feeding and characteristics related to their population dynamics such as fecundity and survival were significantly influenced by water nutrient availability and that environmental nutrient availability will influence the control potential of this species should it be released in South Africa. Cornops aquaticum shows promise as a biocontrol agent for water hyacinth but additional factors that were not investigated in this study such as compatibility with the South African climate and the current water hyacinth biocontrol agents need to be combined with these data to make a decision on its release. Possible management options for this species if it is to be introduced into South Africa are discussed.
- Full Text:
Evaluation of an implemented quality management system (QMS) at one of the South African government departments: employee perceptions of the effect of the QMS intervention
- Authors: Maluleke, Yinywane Leon
- Date: 2009
- Subjects: Total quality management in government Public administration -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:739 , http://hdl.handle.net/10962/d1003859
- Description: This study is about the employee perceptions of the effect of the Quality Management System intervention that was implemented at one of South Africa’s government departments. This organisation’s Quality Management System being one of the first in the government or public sector in South Africa to be implemented, creates the possibility for this Quality Management System model to be used to develop Quality Management Systems in other departments or organisations belonging to the government or the public sector in South Africa and the Southern African region. According to Madu & Kuei (1995), Quality Management System describes a situation where all business functions are involved in a process of continuous quality improvement. This implies that the development and implementation of Quality Management Systems in government departments and the public sector will improve the quality of services delivery. The findings of this study indicated that a Quality Management System can be used to improve the level of service delivery in the public sector. The Quality Management System should be planned developed and implemented over a period of time in five phases (i) Phase 1 - Determination of the scope of Quality Management System implementation (ii) Phase 2 – Training (iii) Phase 3 – Development of Procedures (iv) Phase 4 – Pilot implementation of procedures (v) Phase 5 – Evaluation of Quality Management System and rollout. It usually takes three or more years to establish an organisation-wide Quality Management System, although technical improvement to the workflow can be as quickly as six to eight months. And finally, for the Quality Management System to be developed, implemented and maintained successfully, Maximisation of Performance objectives, Good Leadership, Motivation of staff, Implementation of Change Management, Employee Involvement, Long-term Top Management Commitment, Provision of Training, Introduction of Quality Improvement Projects, Measuring Quality Management System Progress and Reward Accomplishment, are the fundamental concepts or principles that should be considered.
- Full Text:
- Authors: Maluleke, Yinywane Leon
- Date: 2009
- Subjects: Total quality management in government Public administration -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:739 , http://hdl.handle.net/10962/d1003859
- Description: This study is about the employee perceptions of the effect of the Quality Management System intervention that was implemented at one of South Africa’s government departments. This organisation’s Quality Management System being one of the first in the government or public sector in South Africa to be implemented, creates the possibility for this Quality Management System model to be used to develop Quality Management Systems in other departments or organisations belonging to the government or the public sector in South Africa and the Southern African region. According to Madu & Kuei (1995), Quality Management System describes a situation where all business functions are involved in a process of continuous quality improvement. This implies that the development and implementation of Quality Management Systems in government departments and the public sector will improve the quality of services delivery. The findings of this study indicated that a Quality Management System can be used to improve the level of service delivery in the public sector. The Quality Management System should be planned developed and implemented over a period of time in five phases (i) Phase 1 - Determination of the scope of Quality Management System implementation (ii) Phase 2 – Training (iii) Phase 3 – Development of Procedures (iv) Phase 4 – Pilot implementation of procedures (v) Phase 5 – Evaluation of Quality Management System and rollout. It usually takes three or more years to establish an organisation-wide Quality Management System, although technical improvement to the workflow can be as quickly as six to eight months. And finally, for the Quality Management System to be developed, implemented and maintained successfully, Maximisation of Performance objectives, Good Leadership, Motivation of staff, Implementation of Change Management, Employee Involvement, Long-term Top Management Commitment, Provision of Training, Introduction of Quality Improvement Projects, Measuring Quality Management System Progress and Reward Accomplishment, are the fundamental concepts or principles that should be considered.
- Full Text:
Exchange rate pass‐through to import prices in South Africa: is there asymmetry?
- Karoro, Tapiwa D, Aziakpono, Meshach J, Cattaneo, Nicolette S
- Authors: Karoro, Tapiwa D , Aziakpono, Meshach J , Cattaneo, Nicolette S
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469753 , vital:77291 , https://doi.org/10.1111/j.1813-6982.2009.01216.x
- Description: This paper examines the magnitude and speed of exchange rate pass‐through (ERPT) to import prices in South Africa. It further explores whether the direction and size of changes in the exchange rate have different pass‐through effects on import prices, i.e. whether the exchange rate pass‐through is symmetric or asymmetric. The findings of the study suggest that ERPT in South Africa is incomplete but relatively high. Furthermore, ERPT is found to be higher in periods of rand depreciation than appreciation, which supports the binding quantity constraint theory. There is also evidence to suggest that pass‐through is slightly higher in periods of small changes than large changes in the exchange rate in harmony with the menu cost theory when the invoices are denominated in the exporters' currency.
- Full Text:
- Authors: Karoro, Tapiwa D , Aziakpono, Meshach J , Cattaneo, Nicolette S
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469753 , vital:77291 , https://doi.org/10.1111/j.1813-6982.2009.01216.x
- Description: This paper examines the magnitude and speed of exchange rate pass‐through (ERPT) to import prices in South Africa. It further explores whether the direction and size of changes in the exchange rate have different pass‐through effects on import prices, i.e. whether the exchange rate pass‐through is symmetric or asymmetric. The findings of the study suggest that ERPT in South Africa is incomplete but relatively high. Furthermore, ERPT is found to be higher in periods of rand depreciation than appreciation, which supports the binding quantity constraint theory. There is also evidence to suggest that pass‐through is slightly higher in periods of small changes than large changes in the exchange rate in harmony with the menu cost theory when the invoices are denominated in the exporters' currency.
- Full Text:
Exploratory mathematics talk in a second language: a sociolinguistic perspective:
- Graven, Mellony, Robertson, Sally-Ann
- Authors: Graven, Mellony , Robertson, Sally-Ann
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69907 , vital:29594 , https://doi.org/10.1007/s11858-018-0952-2
- Description: This paper illuminates challenges confronting teachers and students at the literacy/numeracy interface in contexts where students have not developed sufficient English language proficiency to be learning mathematics through English but, due to socio-politically and economically driven perceptions are being taught in English. We analyse transcript data of classroom talk in a South African grade 4 mathematics lesson on fractions. Together with interview data, the lesson data highlight some of the consequences students’ diminished access to their home language appear to have on their access to mathematical meaning-making.
- Full Text:
- Authors: Graven, Mellony , Robertson, Sally-Ann
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69907 , vital:29594 , https://doi.org/10.1007/s11858-018-0952-2
- Description: This paper illuminates challenges confronting teachers and students at the literacy/numeracy interface in contexts where students have not developed sufficient English language proficiency to be learning mathematics through English but, due to socio-politically and economically driven perceptions are being taught in English. We analyse transcript data of classroom talk in a South African grade 4 mathematics lesson on fractions. Together with interview data, the lesson data highlight some of the consequences students’ diminished access to their home language appear to have on their access to mathematical meaning-making.
- Full Text:
Exploring job search and the causes of endogenous unemployment: evidence from Duncan Village, South Africa
- Authors: Duff, Patrick Alexander
- Date: 2009
- Subjects: Unemployment , Unemployment -- Social aspects -- South Africa -- East London -- Duncan Village , Job hunting -- South Africa -- East London -- Duncan Village , Labor market -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: vital:1026
- Description: Despite high rates of unemployment in South Africa, there is little consensus about its origins and solutions to the problem. Job search (how and when people search for work)is one aspect of the unemployment problem. Job search is shown to be a complex process strongly linked to the endogenous structure of the labour market. The flaws in traditional methods (theoretical and measurement) highlight this. Using data from a tailor-made survey in Duncan Village (a peri-urban area in Buffalo City, South Africa) the research examines factors that influence the effectiveness of job search. The results show that mode of search (how people look for work) is used as a signal by employers. Degrees of success are stratified amongst searchers using either ‘word of mouth’, place-to-place or formal modes of search. The thesis provides a method-test to reveal a complex body of evidence that has yet to be fully explored by practitioners in this field.
- Full Text:
- Authors: Duff, Patrick Alexander
- Date: 2009
- Subjects: Unemployment , Unemployment -- Social aspects -- South Africa -- East London -- Duncan Village , Job hunting -- South Africa -- East London -- Duncan Village , Labor market -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: vital:1026
- Description: Despite high rates of unemployment in South Africa, there is little consensus about its origins and solutions to the problem. Job search (how and when people search for work)is one aspect of the unemployment problem. Job search is shown to be a complex process strongly linked to the endogenous structure of the labour market. The flaws in traditional methods (theoretical and measurement) highlight this. Using data from a tailor-made survey in Duncan Village (a peri-urban area in Buffalo City, South Africa) the research examines factors that influence the effectiveness of job search. The results show that mode of search (how people look for work) is used as a signal by employers. Degrees of success are stratified amongst searchers using either ‘word of mouth’, place-to-place or formal modes of search. The thesis provides a method-test to reveal a complex body of evidence that has yet to be fully explored by practitioners in this field.
- Full Text:
Exploring Learner Participation in Waste-Management Activities in a Rural Botswana Primary School
- Authors: Silo, Nthalivi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386509 , vital:68148 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122820"
- Description: In Botswana, participation in environmental learning activities has been perceived as a central component of environmental education in formal education. Driven by the need to implement the objective of making the participatory approach part of the infusion of environmental education in the school curriculum as prescribed by the infusion policy, Botswana schools have come up with initiatives to involve learners in environmental education activities that seem to have ‘a direct, perceived benefit to the learners’ (NEESAP, 2007:9). Within this approach it is expected that learners should participate in these activities. However, Ketlhoilwe (2007) revealed that there has been a normalisation of environmental education into existing school culture through equating waste-management activities with environmental education. This generally entails cleaning activities by learners to maintain ‘clean schools’, which is directly associated with environmental education. Drawing from detailed case study data in one rural primary school with Standard 6 learners, I used Cultural Historical Activity Theory to investigate and explain how learners participate in these waste-management activities. Findings from this study revealed that attempts by teachers to meet the policy imperative through prescription of rules, and ascribing roles to learners in waste-management activities, create tensions. This gave rise to an elusive object of learner participation, as the purpose for their participation in these activities is not clear.
- Full Text:
- Authors: Silo, Nthalivi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386509 , vital:68148 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122820"
- Description: In Botswana, participation in environmental learning activities has been perceived as a central component of environmental education in formal education. Driven by the need to implement the objective of making the participatory approach part of the infusion of environmental education in the school curriculum as prescribed by the infusion policy, Botswana schools have come up with initiatives to involve learners in environmental education activities that seem to have ‘a direct, perceived benefit to the learners’ (NEESAP, 2007:9). Within this approach it is expected that learners should participate in these activities. However, Ketlhoilwe (2007) revealed that there has been a normalisation of environmental education into existing school culture through equating waste-management activities with environmental education. This generally entails cleaning activities by learners to maintain ‘clean schools’, which is directly associated with environmental education. Drawing from detailed case study data in one rural primary school with Standard 6 learners, I used Cultural Historical Activity Theory to investigate and explain how learners participate in these waste-management activities. Findings from this study revealed that attempts by teachers to meet the policy imperative through prescription of rules, and ascribing roles to learners in waste-management activities, create tensions. This gave rise to an elusive object of learner participation, as the purpose for their participation in these activities is not clear.
- Full Text:
Exploring risk related to future climates through role-playing games: the African catchment game
- Rowntree, Kate M, Fraenkel, Linda A, Fox, Roddy C
- Authors: Rowntree, Kate M , Fraenkel, Linda A , Fox, Roddy C
- Date: 2009
- Language: English
- Type: Conference paper
- Identifier: vital:6671 , http://hdl.handle.net/10962/d1006807
- Description: Risk is the result of two interacting components: hazard and vulnerability. Climatic hazards are related to extrinsic factors such as drought or severe storms. Vul- nerability is the result of intrinsic factors that often arise from the socio-political- economic context. The interplay of risk and vulnerability is difficult to predict. Although computer models have been widely used to forecast climate related risk, albeit with con- siderable uncertainty, they can never capture sufficiently the vulnerability of human sys- tems to these hazards. Role-playing games can be used more realistically to simulate pos- sible outcomes of different climate change scenarios, and allow players to reflect on their significance. The authors have developed the African Catchment Game to simulate a wa- ter scarce African country. Risk can be modelled mechanistically by changing the nature of the annual rainfall input. Vulnerability can in part be modelled by changing the start- ing parameters (such as access to land and resources) and, secondly, through the unpredictable response of players to game dynamics. Players’ reflections demonstrate that through the game they become more aware of the concept of risk and the complex response of individuals and societies that determine their vulnerability to climatic hazards. This paper reflects on the potential for developing the game further as a tool for participatory learning around climate change, based on the authors’ experience of playing the game with participants from South Africa.
- Full Text:
- Authors: Rowntree, Kate M , Fraenkel, Linda A , Fox, Roddy C
- Date: 2009
- Language: English
- Type: Conference paper
- Identifier: vital:6671 , http://hdl.handle.net/10962/d1006807
- Description: Risk is the result of two interacting components: hazard and vulnerability. Climatic hazards are related to extrinsic factors such as drought or severe storms. Vul- nerability is the result of intrinsic factors that often arise from the socio-political- economic context. The interplay of risk and vulnerability is difficult to predict. Although computer models have been widely used to forecast climate related risk, albeit with con- siderable uncertainty, they can never capture sufficiently the vulnerability of human sys- tems to these hazards. Role-playing games can be used more realistically to simulate pos- sible outcomes of different climate change scenarios, and allow players to reflect on their significance. The authors have developed the African Catchment Game to simulate a wa- ter scarce African country. Risk can be modelled mechanistically by changing the nature of the annual rainfall input. Vulnerability can in part be modelled by changing the start- ing parameters (such as access to land and resources) and, secondly, through the unpredictable response of players to game dynamics. Players’ reflections demonstrate that through the game they become more aware of the concept of risk and the complex response of individuals and societies that determine their vulnerability to climatic hazards. This paper reflects on the potential for developing the game further as a tool for participatory learning around climate change, based on the authors’ experience of playing the game with participants from South Africa.
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Exploring the consequences of perceptions of the divine, and the church, in the making of self-identity: a case study of congregants from Roman Catholic and Charismatic communities in East London, South Africa
- Authors: Sundberg, Dianne
- Date: 2009
- Subjects: Giddens, Anthony Catholic Church -- South Africa -- East London -- Case studies Catholic Church -- Doctrines Glory of God -- Case studies Church -- South Africa -- East London -- Case studies Feminist theology -- South Africa Self -- Case studies Identity (Psychology) -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3298 , http://hdl.handle.net/10962/d1003086
- Description: This thesis explores the impact and consequences of the teachings of the church, perceptions of The Divine [God] and of Mary, in the making of personal identity. In spite of secularisation and the prediction that the church would collapse in the face of modern science, recent evidence suggests that - in its various forms - religion, and belief in a higher power remain important and potentially powerful aspects in society. A foundation stone of the Christian faith is the doctrine of Imago Dei: humanity created in the image of The Divine. Although not male, The Divine is repeatedly spoken of - and addressed - in anthropomorphic masculine terms, but perceived in gender-specific stereotypical terms. Alongside The Divine - in the Roman Catholic Church - is Mary, the mother of Jesus. She is spoken of in feminine terms, but is also perceived in gender-specific stereotypical terms. Although not officially considered to be divine, Mary fulfils important needs in the life of the believer and it is in this context that her influence is evaluated. The role of the church as a community - and social institution - is also explored, based on Giddens’ theories of identity development. Belonging to a church community can provide a context for relationship, continuity, and trust. However, this potentially positive environment can have negative implications on self-identity in that restrictions on self-expression and personal choice can be as limiting as the sense of belonging is liberating. The patriarchal nature of the church is deemed to be of immense relevance. In order to establish the role of the church, The Divine, and Mary in the making of self-identity, in-depth interviews were conducted with twelve research participants belonging to Charismatic and Roman Catholic congregations, and Giddens’ criteria for self-identity development was used as the standard for evaluating participants’ personal sense of self-identity. Explored from the perspective of feminist theology, the findings of this qualitative research project suggest that it is more than gender language regarding The Divine that affects the agent’s perception of The Divine, and that the role of the church in identity formation is not uniform in its influence. It also concludes that perceptions of Mary can be influential in the development of selfidentity.
- Full Text:
- Authors: Sundberg, Dianne
- Date: 2009
- Subjects: Giddens, Anthony Catholic Church -- South Africa -- East London -- Case studies Catholic Church -- Doctrines Glory of God -- Case studies Church -- South Africa -- East London -- Case studies Feminist theology -- South Africa Self -- Case studies Identity (Psychology) -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3298 , http://hdl.handle.net/10962/d1003086
- Description: This thesis explores the impact and consequences of the teachings of the church, perceptions of The Divine [God] and of Mary, in the making of personal identity. In spite of secularisation and the prediction that the church would collapse in the face of modern science, recent evidence suggests that - in its various forms - religion, and belief in a higher power remain important and potentially powerful aspects in society. A foundation stone of the Christian faith is the doctrine of Imago Dei: humanity created in the image of The Divine. Although not male, The Divine is repeatedly spoken of - and addressed - in anthropomorphic masculine terms, but perceived in gender-specific stereotypical terms. Alongside The Divine - in the Roman Catholic Church - is Mary, the mother of Jesus. She is spoken of in feminine terms, but is also perceived in gender-specific stereotypical terms. Although not officially considered to be divine, Mary fulfils important needs in the life of the believer and it is in this context that her influence is evaluated. The role of the church as a community - and social institution - is also explored, based on Giddens’ theories of identity development. Belonging to a church community can provide a context for relationship, continuity, and trust. However, this potentially positive environment can have negative implications on self-identity in that restrictions on self-expression and personal choice can be as limiting as the sense of belonging is liberating. The patriarchal nature of the church is deemed to be of immense relevance. In order to establish the role of the church, The Divine, and Mary in the making of self-identity, in-depth interviews were conducted with twelve research participants belonging to Charismatic and Roman Catholic congregations, and Giddens’ criteria for self-identity development was used as the standard for evaluating participants’ personal sense of self-identity. Explored from the perspective of feminist theology, the findings of this qualitative research project suggest that it is more than gender language regarding The Divine that affects the agent’s perception of The Divine, and that the role of the church in identity formation is not uniform in its influence. It also concludes that perceptions of Mary can be influential in the development of selfidentity.
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Extending the NFComms: framework for bulk data transfers
- Nottingham, Alastair, Irwin, Barry V W
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430164 , vital:72670 , https://doi.org/10.1145/1632149.1632170
- Description: Packet analysis is an important aspect of network security, which typi-cally relies on a flexible packet filtering system to extrapolate important packet information from each processed packet. Packet analysis is a computationally intensive, highly parallelisable task, and as such, clas-sification of large packet sets, such as those collected by a network tel-escope, can require significant processing time. We wish to improve upon this, through parallel classification on a GPU. In this paper, we first consider the OpenCL architecture and its applicability to packet analy-sis. We then introduce a number of packet demultiplexing and routing algorithms, and finally present a discussion on how some of these techniques may be leveraged within a GPGPU context to improve packet classification speeds.
- Full Text:
- Authors: Nottingham, Alastair , Irwin, Barry V W
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430164 , vital:72670 , https://doi.org/10.1145/1632149.1632170
- Description: Packet analysis is an important aspect of network security, which typi-cally relies on a flexible packet filtering system to extrapolate important packet information from each processed packet. Packet analysis is a computationally intensive, highly parallelisable task, and as such, clas-sification of large packet sets, such as those collected by a network tel-escope, can require significant processing time. We wish to improve upon this, through parallel classification on a GPU. In this paper, we first consider the OpenCL architecture and its applicability to packet analy-sis. We then introduce a number of packet demultiplexing and routing algorithms, and finally present a discussion on how some of these techniques may be leveraged within a GPGPU context to improve packet classification speeds.
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Factors enabling and constraining ICT implementation in schools: a multiple case study of three secondary schools in Lesotho
- Authors: Kalake, Matsitso
- Date: 2009
- Subjects: Education -- Lesotho Computer-assisted instruction -- Lesotho Information technology -- Lesotho Educational technology -- Lesotho Education, Secondary -- Lesotho -- Data processing Education -- Lesotho -- Computer network resources Educational innovations -- Lesotho Educational change -- Lesotho
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1858 , http://hdl.handle.net/10962/d1004539
- Description: This study focused on the implementation of ICTs in secondary schools in Lesotho. The main question addressed was: What are the enabling and constraining factors in the implementation of ICTs in schools? The work was undertaken in recognition of the fact that schools in the country were autonomously acquiring computers and using a variety of curricula without much coordination and policies from the government. There were factors encouraging schools to delve into this educational change: and challenges were already evident. This required further investigation. The research approach commenced with a critical review of the literature. Literature was drawn from developed and developing countries in order to understand the process of ICT implementation from a variety of contexts. The enquiry about the implementation process in all the countries focused on the rationale behind the use of ICTs in schools. ICT policies guiding implementation, principal leadership, teacher professional development and ICT resources. The literature review was followed by case studies of three secondary schools in Mafeteng district in Lesotho. Using both qualitative and quantitative methods of research, the study sought to determine from key people in three case study schools their overall understanding of how the process of implementation was carried out and what they perceived as enablers and constraints. The findings revealed that planning, access arrangements, training, support and to a lesser extent resources played a role in either impeding or encouraging the key ICT implementers at school and classroom level. Additionally, the key role of the principal and the MoE were highlighted in the study.
- Full Text:
- Authors: Kalake, Matsitso
- Date: 2009
- Subjects: Education -- Lesotho Computer-assisted instruction -- Lesotho Information technology -- Lesotho Educational technology -- Lesotho Education, Secondary -- Lesotho -- Data processing Education -- Lesotho -- Computer network resources Educational innovations -- Lesotho Educational change -- Lesotho
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1858 , http://hdl.handle.net/10962/d1004539
- Description: This study focused on the implementation of ICTs in secondary schools in Lesotho. The main question addressed was: What are the enabling and constraining factors in the implementation of ICTs in schools? The work was undertaken in recognition of the fact that schools in the country were autonomously acquiring computers and using a variety of curricula without much coordination and policies from the government. There were factors encouraging schools to delve into this educational change: and challenges were already evident. This required further investigation. The research approach commenced with a critical review of the literature. Literature was drawn from developed and developing countries in order to understand the process of ICT implementation from a variety of contexts. The enquiry about the implementation process in all the countries focused on the rationale behind the use of ICTs in schools. ICT policies guiding implementation, principal leadership, teacher professional development and ICT resources. The literature review was followed by case studies of three secondary schools in Mafeteng district in Lesotho. Using both qualitative and quantitative methods of research, the study sought to determine from key people in three case study schools their overall understanding of how the process of implementation was carried out and what they perceived as enablers and constraints. The findings revealed that planning, access arrangements, training, support and to a lesser extent resources played a role in either impeding or encouraging the key ICT implementers at school and classroom level. Additionally, the key role of the principal and the MoE were highlighted in the study.
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Fanon’s Curse: re-imagining Marxism in South Africa’s age of retreat
- Helliker, Kirk D, Vale, Peter C J
- Authors: Helliker, Kirk D , Vale, Peter C J
- Date: 2009
- Language: English
- Type: conference paper , text
- Identifier: http://hdl.handle.net/10962/61029 , vital:27924 , http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.587.740&rep=rep1&type=pdf
- Description: Given its growing, even dark, reputation for xenophobia, it seems extraordinary that South Africa remains open to ideas from the outside. Fifteen years after apartheid in South Africa ended, the country’s great cities are branded with the same imported images that clutter glittering malls in New York, London or Sydney. The rapidity of this makeover from apartheid’s grey conformity is held to be testimony to the success of neo-liberal globalisation which was enthusiastically embraced with apartheid’s ending.
- Full Text:
- Authors: Helliker, Kirk D , Vale, Peter C J
- Date: 2009
- Language: English
- Type: conference paper , text
- Identifier: http://hdl.handle.net/10962/61029 , vital:27924 , http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.587.740&rep=rep1&type=pdf
- Description: Given its growing, even dark, reputation for xenophobia, it seems extraordinary that South Africa remains open to ideas from the outside. Fifteen years after apartheid in South Africa ended, the country’s great cities are branded with the same imported images that clutter glittering malls in New York, London or Sydney. The rapidity of this makeover from apartheid’s grey conformity is held to be testimony to the success of neo-liberal globalisation which was enthusiastically embraced with apartheid’s ending.
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Film Review: Hollywood on Safari
- Authors: Amner, Roderick J
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142680 , vital:38101 , https://doi.org/10.1386/jams.1.2.335_4
- Description: Film Review: Hollywood on Safari.
- Full Text:
- Authors: Amner, Roderick J
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142680 , vital:38101 , https://doi.org/10.1386/jams.1.2.335_4
- Description: Film Review: Hollywood on Safari.
- Full Text:
Finite fuzzy sets, keychains and their applications
- Authors: Mahlasela, Zuko
- Date: 2009
- Subjects: Fuzzy sets , Finite groups , Lattice theory , Economics -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5406 , http://hdl.handle.net/10962/d1005220 , Fuzzy sets , Finite groups , Lattice theory , Economics -- Mathematical models
- Description: The idea of keychains, an (n+1)-tuple of non-increasing real numbers in the unit interval always including 1, naturally arises in study of finite fuzzy set theory. They are a useful concept in modeling ideas of uncertainty especially those that arise in Economics, Social Sciences, Statistics and other subjects. In this thesis we define and study some basic properties of keychains with reference to Partially Ordered Sets, Lattices, Chains and Finite Fuzzy Sets. We then examine the role of keychains and their lattice diagrams in representing uncertainties that arise in such problems as in preferential voting patterns, outcomes of competitions and in Economics - Preference Relations.
- Full Text:
- Authors: Mahlasela, Zuko
- Date: 2009
- Subjects: Fuzzy sets , Finite groups , Lattice theory , Economics -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5406 , http://hdl.handle.net/10962/d1005220 , Fuzzy sets , Finite groups , Lattice theory , Economics -- Mathematical models
- Description: The idea of keychains, an (n+1)-tuple of non-increasing real numbers in the unit interval always including 1, naturally arises in study of finite fuzzy set theory. They are a useful concept in modeling ideas of uncertainty especially those that arise in Economics, Social Sciences, Statistics and other subjects. In this thesis we define and study some basic properties of keychains with reference to Partially Ordered Sets, Lattices, Chains and Finite Fuzzy Sets. We then examine the role of keychains and their lattice diagrams in representing uncertainties that arise in such problems as in preferential voting patterns, outcomes of competitions and in Economics - Preference Relations.
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Flies in the ointment a morphological and molecular comparison of Lucilia cuprina and Lucilia sericata (Diptera: Calliphoridae) in South Africa
- Tourle, Robyn, Downie, Douglas A, Villet, Martin H
- Authors: Tourle, Robyn , Downie, Douglas A , Villet, Martin H
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442156 , vital:73963 , https://doi.org/10.1111/j.1365-2915.2008.00765.x
- Description: Complementary nuclear (28S rRNA) and mitochondrial (COI) genes were sequenced from blowflies that phenotypically resembled Lucilia cuprina (W.), Lucilia sericata (Meigen) or exhibited characters of both species. The aim was to test a long‐held hypothesis that these species hybridize under natural conditions in South Africa (Ullyett, 1945). Blowflies were obtained predominantly from the Cape Town metropolitan area, but reference samples were acquired for L. sericata from Pretoria. Several L. cuprina‐like flies were shown to possess a conflicting combination of nuclear and mitochondrial genes that has also been seen in Hawaiian specimens. Homoplasy, sampling of pseudogenes, hybridization and incomplete lineage sorting are discussed as possible hypotheses for the pattern and the latter is concluded to represent the most likely explanation.
- Full Text:
- Authors: Tourle, Robyn , Downie, Douglas A , Villet, Martin H
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442156 , vital:73963 , https://doi.org/10.1111/j.1365-2915.2008.00765.x
- Description: Complementary nuclear (28S rRNA) and mitochondrial (COI) genes were sequenced from blowflies that phenotypically resembled Lucilia cuprina (W.), Lucilia sericata (Meigen) or exhibited characters of both species. The aim was to test a long‐held hypothesis that these species hybridize under natural conditions in South Africa (Ullyett, 1945). Blowflies were obtained predominantly from the Cape Town metropolitan area, but reference samples were acquired for L. sericata from Pretoria. Several L. cuprina‐like flies were shown to possess a conflicting combination of nuclear and mitochondrial genes that has also been seen in Hawaiian specimens. Homoplasy, sampling of pseudogenes, hybridization and incomplete lineage sorting are discussed as possible hypotheses for the pattern and the latter is concluded to represent the most likely explanation.
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Fluorescence studies of quantum dots and zinc tetraamino phthalocyanine conjugates
- Britton, Jonathan, Antunes, Edith M, Nyokong, Tebello
- Authors: Britton, Jonathan , Antunes, Edith M , Nyokong, Tebello
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6565 , http://hdl.handle.net/10962/d1004124
- Description: CdTe Qds capped with mercapto propionic acid (MPA) were covalently linked to zinc tetraamino phthalocyanine (ZnTAPc) using N-ethyl-N(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) as the coupling agents. The results presented give evidence in favour of the formation of an amide bond between ZnTAPc and CdTe QDs. Both the linked ZnTAPc–QD complexes and a mixture of QDs and ZnTAPc (i.e. without chemical linking) showed Förster resonance energy transfer (FRET). ZnTAPc quenched the QDs emission, giving quenching constants in the order of 103 M−1.
- Full Text:
- Authors: Britton, Jonathan , Antunes, Edith M , Nyokong, Tebello
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6565 , http://hdl.handle.net/10962/d1004124
- Description: CdTe Qds capped with mercapto propionic acid (MPA) were covalently linked to zinc tetraamino phthalocyanine (ZnTAPc) using N-ethyl-N(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) as the coupling agents. The results presented give evidence in favour of the formation of an amide bond between ZnTAPc and CdTe QDs. Both the linked ZnTAPc–QD complexes and a mixture of QDs and ZnTAPc (i.e. without chemical linking) showed Förster resonance energy transfer (FRET). ZnTAPc quenched the QDs emission, giving quenching constants in the order of 103 M−1.
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Forecasting solar cycle 24 using neural networks
- Authors: Uwamahoro, Jean
- Date: 2009
- Subjects: Solar cycle , Neural networks (Computer science) , Ionosphere , Ionospheric electron density , Ionospheric forecasting , Solar thermal energy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5468 , http://hdl.handle.net/10962/d1005253 , Solar cycle , Neural networks (Computer science) , Ionosphere , Ionospheric electron density , Ionospheric forecasting , Solar thermal energy
- Description: The ability to predict the future behavior of solar activity has become of extreme importance due to its effect on the near-Earth environment. Predictions of both the amplitude and timing of the next solar cycle will assist in estimating the various consequences of Space Weather. Several prediction techniques have been applied and have achieved varying degrees of success in the domain of solar activity prediction. These techniques include, for example, neural networks and geomagnetic precursor methods. In this thesis, various neural network based models were developed and the model considered to be optimum was used to estimate the shape and timing of solar cycle 24. Given the recent success of the geomagnetic precusrsor methods, geomagnetic activity as measured by the aa index is considered among the main inputs to the neural network model. The neural network model developed is also provided with the time input parameters defining the year and the month of a particular solar cycle, in order to characterise the temporal behaviour of sunspot number as observed during the last 10 solar cycles. The structure of input-output patterns to the neural network is constructed in such a way that the network learns the relationship between the aa index values of a particular cycle, and the sunspot number values of the following cycle. Assuming January 2008 as the minimum preceding solar cycle 24, the shape and amplitude of solar cycle 24 is estimated in terms of monthly mean and smoothed monthly sunspot number. This new prediction model estimates an average solar cycle 24, with the maximum occurring around June 2012 [± 11 months], with a smoothed monthly maximum sunspot number of 121 ± 9.
- Full Text:
- Authors: Uwamahoro, Jean
- Date: 2009
- Subjects: Solar cycle , Neural networks (Computer science) , Ionosphere , Ionospheric electron density , Ionospheric forecasting , Solar thermal energy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5468 , http://hdl.handle.net/10962/d1005253 , Solar cycle , Neural networks (Computer science) , Ionosphere , Ionospheric electron density , Ionospheric forecasting , Solar thermal energy
- Description: The ability to predict the future behavior of solar activity has become of extreme importance due to its effect on the near-Earth environment. Predictions of both the amplitude and timing of the next solar cycle will assist in estimating the various consequences of Space Weather. Several prediction techniques have been applied and have achieved varying degrees of success in the domain of solar activity prediction. These techniques include, for example, neural networks and geomagnetic precursor methods. In this thesis, various neural network based models were developed and the model considered to be optimum was used to estimate the shape and timing of solar cycle 24. Given the recent success of the geomagnetic precusrsor methods, geomagnetic activity as measured by the aa index is considered among the main inputs to the neural network model. The neural network model developed is also provided with the time input parameters defining the year and the month of a particular solar cycle, in order to characterise the temporal behaviour of sunspot number as observed during the last 10 solar cycles. The structure of input-output patterns to the neural network is constructed in such a way that the network learns the relationship between the aa index values of a particular cycle, and the sunspot number values of the following cycle. Assuming January 2008 as the minimum preceding solar cycle 24, the shape and amplitude of solar cycle 24 is estimated in terms of monthly mean and smoothed monthly sunspot number. This new prediction model estimates an average solar cycle 24, with the maximum occurring around June 2012 [± 11 months], with a smoothed monthly maximum sunspot number of 121 ± 9.
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Foreign policy ambiguity on the part of an emergent middle power: South African foreign policy through other lenses
- Serrão, Olivier, Bischoff, Paul, 1954-
- Authors: Serrão, Olivier , Bischoff, Paul, 1954-
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161464 , vital:40629 , DOI: 10.1080/02589341003600189
- Description: This paper attempts to address the ambiguity so frequently highlighted in South Africa's post-apartheid foreign policy. Three central arguments are put forward. Firstly, it is argued that traditional accounts of South Africa's foreign policy, utilizing rationalist or ‘mainstream’ theories of International Relations, are insufficient in themselves to explain the complexities inherent in the country's foreign policy. In this regard, constructivist IR theory offers several key insights into studies of South Africa's foreign policy. Secondly, although it is argued that constructivism, particularly its focus on identity, is crucial to understanding South African foreign policy, it alone cannot sufficiently explain its reception or results on the world stage. Finally, it is argued that in order to fully appreciate both the nature and effects of South Africa's foreign policy, a mixed focus, incorporating insights from both constructivist and materialist-based theories of IR, is necessary.
- Full Text:
- Authors: Serrão, Olivier , Bischoff, Paul, 1954-
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161464 , vital:40629 , DOI: 10.1080/02589341003600189
- Description: This paper attempts to address the ambiguity so frequently highlighted in South Africa's post-apartheid foreign policy. Three central arguments are put forward. Firstly, it is argued that traditional accounts of South Africa's foreign policy, utilizing rationalist or ‘mainstream’ theories of International Relations, are insufficient in themselves to explain the complexities inherent in the country's foreign policy. In this regard, constructivist IR theory offers several key insights into studies of South Africa's foreign policy. Secondly, although it is argued that constructivism, particularly its focus on identity, is crucial to understanding South African foreign policy, it alone cannot sufficiently explain its reception or results on the world stage. Finally, it is argued that in order to fully appreciate both the nature and effects of South Africa's foreign policy, a mixed focus, incorporating insights from both constructivist and materialist-based theories of IR, is necessary.
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Framing economic news: an examination of coverage of the Growth, Employment and Redistribution (GEAR) strategy in Business Day
- Authors: Mudzamiri, Wonder Tariro
- Date: 2009
- Subjects: Business day English newspapers -- South Africa South African newspapers Mass media -- Economic aspects Economic development -- South Africa South Africa -- Economic policy South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3469 , http://hdl.handle.net/10962/d1002924
- Description: This thesis examines the way in which Business Day portrayed the neo-liberal logic of the Growth, Employment and Redistribution (GEAR) strategy as both common sense and natural. It utilises framing analysis, adapting its application to the context of media studies as the guiding theoretical framework in trying to understand how Business Day, as representative of the mainstream financial media, frame economic policy issues. Using content analysis, the thesis examines how elite sources are the preferred news sources above ordinary citizens and are thus in a position to shape news content in line with their neo-liberal views on the economy. The thesis analyses how Business Day, by means of the globalisation frame and other frames, legitimated and in the process perpetuated the GEAR strategy as the macroeconomic policy of choice for South Africa in 1996 against the background of the country’s political transformation and economic policy development in preceding years.
- Full Text:
- Authors: Mudzamiri, Wonder Tariro
- Date: 2009
- Subjects: Business day English newspapers -- South Africa South African newspapers Mass media -- Economic aspects Economic development -- South Africa South Africa -- Economic policy South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3469 , http://hdl.handle.net/10962/d1002924
- Description: This thesis examines the way in which Business Day portrayed the neo-liberal logic of the Growth, Employment and Redistribution (GEAR) strategy as both common sense and natural. It utilises framing analysis, adapting its application to the context of media studies as the guiding theoretical framework in trying to understand how Business Day, as representative of the mainstream financial media, frame economic policy issues. Using content analysis, the thesis examines how elite sources are the preferred news sources above ordinary citizens and are thus in a position to shape news content in line with their neo-liberal views on the economy. The thesis analyses how Business Day, by means of the globalisation frame and other frames, legitimated and in the process perpetuated the GEAR strategy as the macroeconomic policy of choice for South Africa in 1996 against the background of the country’s political transformation and economic policy development in preceding years.
- Full Text: