A bitcoin framework : an alternative payment system for marginalized areas of South Africa using low-end mobile phones
- Authors: Dlamini, Nelisiwe Peaceness
- Date: 2016
- Subjects: Electronic funds transfers -- South Africa Bitcoin -- South Africa Mobile commerce -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/11884 , vital:39115
- Description: The emergence of the cryptocurrency Bitcoin, has invoked the need for developing financial systems that can be used to transfer digital value. This would serve as a solution to developing countries especially the challenged ones, when it comes to accommodating the financial needs of the disadvantaged people. Moreover, it facilitates access to financial services to allow them to transact with ease. Numerous companies have taken advantage of the prevalence of mobile phones and introduced financial platforms to provide financial inclusion to disadvantaged people. Financial institutions and Mobile Network Operators (MNO) have developed platforms such as cell phone banking services, mobile money, mobile wallets, and electronic wallets that can be used to provide affordable financial services. Although this is the case, alternative platforms that are affordable and accessible through mobile phones are still required. Therefore, this study proposes a Bitcoin framework that can be used as an alternative platform through low-end mobile phones to provide access to financial services to the disadvantaged people in marginalized areas. To prove the concept of the proposed Bitcoin framework, a Mobile Bitcoin Wallet System (MBWS) prototype was developed, which allows a person using a low-end mobile phone with no intervening technology such as Internet or Bluetooth, to access a Bitcoin wallet by sending a Short Message Service (SMS). This enables Bitcoin to be accessed more easily and affordably by the people. Thus the developed prototype conceptualizes an alternative payment system or a payment method that can augment the existing payment methods. The MBWS is evaluated to assess if it can offer the services that other platforms offer by being compared to a cell-phone banking service. It was deployed on a computer connected to the Internet to enable a connection to the Bitcoin network and access to the blockchain which records all the transactions that take place in Bitcoin. Although this system provides access to the Bitcoin wallet, for it to be applied to areas where people require an alternative payment system, it still needs to be enhanced for such use. This includes scaling the system and adding more functions to it.
- Full Text:
- Date Issued: 2016
- Authors: Dlamini, Nelisiwe Peaceness
- Date: 2016
- Subjects: Electronic funds transfers -- South Africa Bitcoin -- South Africa Mobile commerce -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/11884 , vital:39115
- Description: The emergence of the cryptocurrency Bitcoin, has invoked the need for developing financial systems that can be used to transfer digital value. This would serve as a solution to developing countries especially the challenged ones, when it comes to accommodating the financial needs of the disadvantaged people. Moreover, it facilitates access to financial services to allow them to transact with ease. Numerous companies have taken advantage of the prevalence of mobile phones and introduced financial platforms to provide financial inclusion to disadvantaged people. Financial institutions and Mobile Network Operators (MNO) have developed platforms such as cell phone banking services, mobile money, mobile wallets, and electronic wallets that can be used to provide affordable financial services. Although this is the case, alternative platforms that are affordable and accessible through mobile phones are still required. Therefore, this study proposes a Bitcoin framework that can be used as an alternative platform through low-end mobile phones to provide access to financial services to the disadvantaged people in marginalized areas. To prove the concept of the proposed Bitcoin framework, a Mobile Bitcoin Wallet System (MBWS) prototype was developed, which allows a person using a low-end mobile phone with no intervening technology such as Internet or Bluetooth, to access a Bitcoin wallet by sending a Short Message Service (SMS). This enables Bitcoin to be accessed more easily and affordably by the people. Thus the developed prototype conceptualizes an alternative payment system or a payment method that can augment the existing payment methods. The MBWS is evaluated to assess if it can offer the services that other platforms offer by being compared to a cell-phone banking service. It was deployed on a computer connected to the Internet to enable a connection to the Bitcoin network and access to the blockchain which records all the transactions that take place in Bitcoin. Although this system provides access to the Bitcoin wallet, for it to be applied to areas where people require an alternative payment system, it still needs to be enhanced for such use. This includes scaling the system and adding more functions to it.
- Full Text:
- Date Issued: 2016
A comparison of muscle fatigue responses between static and quasi-static exertions
- Authors: Nel, Conrad
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3475 , vital:20502
- Description: Background: This study examined localized muscle fatigue responses from sub-maximal quasi-static work protocols and additionally how it compares to purely static work. The goal was to produce research that enhances the understanding of the demands on muscles during manual work to aid in preventing injuries stemming from localized muscle fatigue. Injury rates remain a problem in manual labour sectors, particularly for the lower back and shoulder regions for the manufacturing, service and construction sectors, and for knee and elbow flexors in the sports sector. Few studies have looked at quasi-static work and what the resulting fatigue characteristics are, especially when compared to purely static or purely dynamic work. This comparison is particularly important due to the fact that risk assessment tools that are currently utilized to assess risk in the working environment are based on fatigue studies that focus on purely static or purely dynamic work. This requires attention as many working situations are neither static nor dynamic, but rather quasi-static in nature, with aspects of both dynamic and static muscle components. The scope of this study only encompasses the comparison between purely static and quasi-static work. Objectives: This study had two objectives, firstly, to determine what the fatigue characteristics of quasi-static work are and how it compares to fully static work. Secondly, to determine whether an underlying static component within an otherwise dynamic muscle force affects localized muscle fatigue compared to quasi-static work that has equal amounts of effort but with no underlying static component. Methods: Four experimental conditions were tested, each on four muscles, namely the medial deltoid, bicep brachii, bicep femoris and erector spinae muscles. To test the two objectives of this study, 16 volunteers performed a five minute fatigue protocol, that either entailed a fully static condition which involved: 1) producing a steady force at 25 percent of maximum voluntary force, 2) a quasi-static condition with fully dynamic muscle force that alternates the required force level between zero and 50 percent of maximum force, 3) a quasi-static condition with an underlying static component of five percent of maximum force, or 4) a quasi-static condition with a large underlying static component of 15 percent of maximum force. All the experimental conditions in this study had the same average workload of 25 percent of maximum voluntary force over time and thus total workload. The dependant variables of interest were ratings of perceived exertion, changes in muscle fibre recruitment (% of maximum EMG activity), maximum force and center frequency from a spectral analysis of the surface electromyography. These were measured throughout the protocols at one minute intervals to determine how muscle fatigue progressed, and how the fatigue responses differed between conditions. Results: The data from comparing fully static and quasi-static work showed that of the variables measured, the rating of perceived exertion (RPE) and maximum force data indicated that for bicep brachii and bicep femoris muscles, fully static work is more fatiguing than work that alternates between zero and 50 percent of maximum force. The results for the medial deltoid and erector spinae muscles were inconclusive. The findings regarding the comparison between quasi-static conditions with and without an underlying static component revealed that an underlying static component results in greater fatigue when compared to a quasi-static condition with no static component. The results may also suggest that a larger static component coupled with a smaller peak force results in less fatigue than a condition with a small underlying static component coupled with a higher peak force in some scenarios, provided total work is kept constant. All conditions had to have the same workload in order to be validly compared and thus the condition with a larger underlying static component had a lower peak force compared to the condition with no underlying static component or the condition with a small underlying static component. Conclusions: This study presented evidence that quasi-static work does not induce fatigue when measured by RPE and drop in maximum force in the same way as static work. Additionally, the results indicate that a larger underlying static component does not necessarily fatigue a muscle faster if the overall workload is kept constant. However, the results do suggest that any underlying static component will increase the demand on a muscle when compared to a muscle exertion with no static component. When considering the available literature on how muscles fatigue during low level static contractions, the current understanding is that the larger the force during a static contraction, the faster the onset of fatigue and decrements in performance occur. The results of this study suggest that this same relationship cannot be applied to quasi-static work where an underlying static component is part of an otherwise dynamic muscle force. Thus total workload or peak force may play a larger role than the static muscle exertion in some scenarios.
- Full Text:
- Date Issued: 2016
- Authors: Nel, Conrad
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3475 , vital:20502
- Description: Background: This study examined localized muscle fatigue responses from sub-maximal quasi-static work protocols and additionally how it compares to purely static work. The goal was to produce research that enhances the understanding of the demands on muscles during manual work to aid in preventing injuries stemming from localized muscle fatigue. Injury rates remain a problem in manual labour sectors, particularly for the lower back and shoulder regions for the manufacturing, service and construction sectors, and for knee and elbow flexors in the sports sector. Few studies have looked at quasi-static work and what the resulting fatigue characteristics are, especially when compared to purely static or purely dynamic work. This comparison is particularly important due to the fact that risk assessment tools that are currently utilized to assess risk in the working environment are based on fatigue studies that focus on purely static or purely dynamic work. This requires attention as many working situations are neither static nor dynamic, but rather quasi-static in nature, with aspects of both dynamic and static muscle components. The scope of this study only encompasses the comparison between purely static and quasi-static work. Objectives: This study had two objectives, firstly, to determine what the fatigue characteristics of quasi-static work are and how it compares to fully static work. Secondly, to determine whether an underlying static component within an otherwise dynamic muscle force affects localized muscle fatigue compared to quasi-static work that has equal amounts of effort but with no underlying static component. Methods: Four experimental conditions were tested, each on four muscles, namely the medial deltoid, bicep brachii, bicep femoris and erector spinae muscles. To test the two objectives of this study, 16 volunteers performed a five minute fatigue protocol, that either entailed a fully static condition which involved: 1) producing a steady force at 25 percent of maximum voluntary force, 2) a quasi-static condition with fully dynamic muscle force that alternates the required force level between zero and 50 percent of maximum force, 3) a quasi-static condition with an underlying static component of five percent of maximum force, or 4) a quasi-static condition with a large underlying static component of 15 percent of maximum force. All the experimental conditions in this study had the same average workload of 25 percent of maximum voluntary force over time and thus total workload. The dependant variables of interest were ratings of perceived exertion, changes in muscle fibre recruitment (% of maximum EMG activity), maximum force and center frequency from a spectral analysis of the surface electromyography. These were measured throughout the protocols at one minute intervals to determine how muscle fatigue progressed, and how the fatigue responses differed between conditions. Results: The data from comparing fully static and quasi-static work showed that of the variables measured, the rating of perceived exertion (RPE) and maximum force data indicated that for bicep brachii and bicep femoris muscles, fully static work is more fatiguing than work that alternates between zero and 50 percent of maximum force. The results for the medial deltoid and erector spinae muscles were inconclusive. The findings regarding the comparison between quasi-static conditions with and without an underlying static component revealed that an underlying static component results in greater fatigue when compared to a quasi-static condition with no static component. The results may also suggest that a larger static component coupled with a smaller peak force results in less fatigue than a condition with a small underlying static component coupled with a higher peak force in some scenarios, provided total work is kept constant. All conditions had to have the same workload in order to be validly compared and thus the condition with a larger underlying static component had a lower peak force compared to the condition with no underlying static component or the condition with a small underlying static component. Conclusions: This study presented evidence that quasi-static work does not induce fatigue when measured by RPE and drop in maximum force in the same way as static work. Additionally, the results indicate that a larger underlying static component does not necessarily fatigue a muscle faster if the overall workload is kept constant. However, the results do suggest that any underlying static component will increase the demand on a muscle when compared to a muscle exertion with no static component. When considering the available literature on how muscles fatigue during low level static contractions, the current understanding is that the larger the force during a static contraction, the faster the onset of fatigue and decrements in performance occur. The results of this study suggest that this same relationship cannot be applied to quasi-static work where an underlying static component is part of an otherwise dynamic muscle force. Thus total workload or peak force may play a larger role than the static muscle exertion in some scenarios.
- Full Text:
- Date Issued: 2016
A longitudinal study of DNS traffic: understanding current DNS practice and abuse
- Authors: Van Zyl, Ignus
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3707 , vital:20537
- Description: This thesis examines a dataset spanning 21 months, containing 3,5 billion DNS packets. Traffic on TCP and UDP port 53, was captured on a production /24 IP block. The purpose of this thesis is twofold. The first is to create an understanding of current practice and behavior within the DNS infrastructure, the second to explore current threats faced by the DNS and the various systems that implement it. This is achieved by drawing on analysis and observations from the captured data. Aspects of the operation of DNS on the greater Internet are considered in this research with reference to the observed trends in the dataset, A thorough analysis of current DNS TTL implementation is made with respect to all response traffic, as well as sections looking at observed DNS TTL values for ,za domain replies and NX DOMAIN flagged replies. This thesis found that TTL values implemented are much lower than has been recommended in previous years, and that the TTL decrease is prevalent in most, but not all EE TTL implementation. With respect to the nature of DNS operations, this thesis also concerns itself with an analysis of the geoloeation of authoritative servers for local (,za) domains, and offers further observations towards the latency generated by the choice of authoritative server location for a given ,za domain. It was found that the majority of ,za domain authoritative servers are international, which results in latency generation that is multiple times greater than observed latencies for local authoritative servers. Further analysis is done with respect to NX DOM AIN behavior captured across the dataset. These findings outlined the cost of DNS miseonfiguration as well as highlighting instances of NXDOMAIN generation through malicious practice. With respect to DNS abuses, original research with respect to long-term scanning generated as a result of amplification attack activity on the greater Internet is presented. Many instances of amplification domain scans were captured during the packet capture, and an attempt is made to correlate that activity temporally with known amplification attack reports. The final area that this thesis deals with is the relatively new field of Bitflipping and Bitsquatting, delivering results on bitflip detection and evaluation over the course of the entire dataset. The detection methodology is outlined, and the final results are compared to findings given in recent bitflip literature.
- Full Text:
- Date Issued: 2016
- Authors: Van Zyl, Ignus
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3707 , vital:20537
- Description: This thesis examines a dataset spanning 21 months, containing 3,5 billion DNS packets. Traffic on TCP and UDP port 53, was captured on a production /24 IP block. The purpose of this thesis is twofold. The first is to create an understanding of current practice and behavior within the DNS infrastructure, the second to explore current threats faced by the DNS and the various systems that implement it. This is achieved by drawing on analysis and observations from the captured data. Aspects of the operation of DNS on the greater Internet are considered in this research with reference to the observed trends in the dataset, A thorough analysis of current DNS TTL implementation is made with respect to all response traffic, as well as sections looking at observed DNS TTL values for ,za domain replies and NX DOMAIN flagged replies. This thesis found that TTL values implemented are much lower than has been recommended in previous years, and that the TTL decrease is prevalent in most, but not all EE TTL implementation. With respect to the nature of DNS operations, this thesis also concerns itself with an analysis of the geoloeation of authoritative servers for local (,za) domains, and offers further observations towards the latency generated by the choice of authoritative server location for a given ,za domain. It was found that the majority of ,za domain authoritative servers are international, which results in latency generation that is multiple times greater than observed latencies for local authoritative servers. Further analysis is done with respect to NX DOM AIN behavior captured across the dataset. These findings outlined the cost of DNS miseonfiguration as well as highlighting instances of NXDOMAIN generation through malicious practice. With respect to DNS abuses, original research with respect to long-term scanning generated as a result of amplification attack activity on the greater Internet is presented. Many instances of amplification domain scans were captured during the packet capture, and an attempt is made to correlate that activity temporally with known amplification attack reports. The final area that this thesis deals with is the relatively new field of Bitflipping and Bitsquatting, delivering results on bitflip detection and evaluation over the course of the entire dataset. The detection methodology is outlined, and the final results are compared to findings given in recent bitflip literature.
- Full Text:
- Date Issued: 2016
A mathematical study on optimal prevention and control strategies for tuberculosis: case study for Port Elizabeth, South Africa
- Authors: Zembe, Pumelela Vincent
- Date: 2016
- Subjects: Tuberculosis -- South Africa -- Port Elizabeth -- Prevention Tuberculosis -- Mathematical models , Tuberculosis -- Case studies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12823 , vital:27124
- Description: In this treatise a SEIR model for the transmission of tuberculosis was proposed. It assumes that the latent infected individuals progress to active tuberculosis through endogenous reactivation and exogenous re-infection and that the individuals who have recovered from the disease through treatment are not immune to tuberculosis re-infection. While most features of the original model were kept, the model was modified to incorporate two control measures in the form of post-exposure tuberculosis prophylaxis for the treatment of latent individuals and tuberculosis therapeutics for the treatmentof individuals with active tuberculosis. Mathematical analysis of the modelwas done under the assumption that the two control measures are positiveconstants. The disease-free equilibrium point was locally asymptotically stable when the basic reproduction number was less than unity and unstable when this epidemic threshold exceeds unity. An optimal control problem was formulated and the necessary conditions for optimality were derived.The numerical results based on data from Port Elizabeth suggest that using both forms of control measures simultaneously is more effective in reducing the total number of infected individuals than applying single controls separately.
- Full Text:
- Date Issued: 2016
- Authors: Zembe, Pumelela Vincent
- Date: 2016
- Subjects: Tuberculosis -- South Africa -- Port Elizabeth -- Prevention Tuberculosis -- Mathematical models , Tuberculosis -- Case studies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12823 , vital:27124
- Description: In this treatise a SEIR model for the transmission of tuberculosis was proposed. It assumes that the latent infected individuals progress to active tuberculosis through endogenous reactivation and exogenous re-infection and that the individuals who have recovered from the disease through treatment are not immune to tuberculosis re-infection. While most features of the original model were kept, the model was modified to incorporate two control measures in the form of post-exposure tuberculosis prophylaxis for the treatment of latent individuals and tuberculosis therapeutics for the treatmentof individuals with active tuberculosis. Mathematical analysis of the modelwas done under the assumption that the two control measures are positiveconstants. The disease-free equilibrium point was locally asymptotically stable when the basic reproduction number was less than unity and unstable when this epidemic threshold exceeds unity. An optimal control problem was formulated and the necessary conditions for optimality were derived.The numerical results based on data from Port Elizabeth suggest that using both forms of control measures simultaneously is more effective in reducing the total number of infected individuals than applying single controls separately.
- Full Text:
- Date Issued: 2016
A situational survey of Siyazondla homestead food production proogramme and food security, poverty alleviation in selected communities of Nkonkobe Local Municipality of the Eastern Cape
- Authors: Phezisa, Bulelani
- Date: 2016
- Subjects: Food security -- South Africa -- Eastern Cape Food supply -- South Africa -- Eastern Cape Poverty -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2392 , vital:27795
- Description: People living in rural areas are continually losing their value, dignity, ubuntu and rural nature of livelihood. Agriculture in these areas characterises the nature of rural livelihood. Traditionally, people living in rural areas were highly dependent on their production from gardens for food, income (barter exchange), and other social activities. Nowadays, that motive and interest is no longer operating at its full potential, so to revive that history and nature, household (homestead) production, certain programmes were introduced to greatly improved the standard of living of the poor, and it has proved to have an impact as it has generated income, and created food stability and employment through the project. Home gardens are there and can be used as the method and the strategy toward improvement and development of the people around the world, more especial to developing countries. Certain programmes that are initiated for acting against the challenges faced by rural people have failed to materialise and operate on their fully potential. The Siyazondla homestead food production programme is the one of the programmes practiced by the government of South Africa to act against such challenges, affecting especially poor people. This study was aimed at assessing the role of Siyazondla homestead food production programme in food security and poverty alleviation in selected communities of Nkonkobe local municipality of the Eastern Cape. It took the form of a case study in Msobomvu, Ngcothoyi and Binfield locations. The Nkonkobe local municipality is demarcated into five major areas: Middledrift, Alice, Seymour, Fort Beaufort and Balfour. The study sample was collected from beneficiaries and non-beneficiaries of the Siyazondla programme. The sample size was 90 respondents, from which in one area, a 15 beneficiaries and anticipated non- beneficiaries were targeted. The target sample from each village was collected from 15 beneficiaries and non-beneficiaries. Many farmers from the study area benefited from the programme, though a limited number was targeted. Therefore, a probability sampling was applied and employed, where there were more than required number of beneficiaries of the programme and anticipated beneficiaries of the programme. The study was effectively and efficiently carried out and achieved with the use of personal interviewing of the recipients by use of questionnaires. The study was analysed by a computerised programme of analyses called SPSS v.2.1 and excel. The objectives of the study based on food security, poverty alleviation and reduction, and also improving nutritious status. The finding of the research clearly indicates the outcome of the programme on livelihood basis of the beneficiaries. Some of the objectives of the programme were achieved, such as food security and nutritious levels, whilst other objectives had shortcomings. The finding of the study also shows that programme, though had original benefits but also there are the anticipated and probable benefits of the programme Siyazondla, such as income, skill of farming, improving social status, and there are some possibilities when the programme is properly implemented. Though the majority of people are concentrated in rural areas, the programme on its own had shortcoming to meet needs of the whole population, as food insecurity, unemployment and poverty are taking its course. The programme on its own had shortcoming such as lack of adequate resource and as results, very few people benefited from the programme. Another shortcoming of the programme is the effectiveness of agricultural extension personnel to certain aspect such as marketing of farmers produce and proper monitoring and evaluation of the programme. Therefore, in the long run programmes of this nature are promising, there will be some development and improvement toward growth and better standards of livelihood. It is through this study that had to assess the structure, procedure, strategies implemented of the programme and impact of the programme to both beneficiaries and anticipated beneficiaries of the programme.
- Full Text:
- Date Issued: 2016
- Authors: Phezisa, Bulelani
- Date: 2016
- Subjects: Food security -- South Africa -- Eastern Cape Food supply -- South Africa -- Eastern Cape Poverty -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2392 , vital:27795
- Description: People living in rural areas are continually losing their value, dignity, ubuntu and rural nature of livelihood. Agriculture in these areas characterises the nature of rural livelihood. Traditionally, people living in rural areas were highly dependent on their production from gardens for food, income (barter exchange), and other social activities. Nowadays, that motive and interest is no longer operating at its full potential, so to revive that history and nature, household (homestead) production, certain programmes were introduced to greatly improved the standard of living of the poor, and it has proved to have an impact as it has generated income, and created food stability and employment through the project. Home gardens are there and can be used as the method and the strategy toward improvement and development of the people around the world, more especial to developing countries. Certain programmes that are initiated for acting against the challenges faced by rural people have failed to materialise and operate on their fully potential. The Siyazondla homestead food production programme is the one of the programmes practiced by the government of South Africa to act against such challenges, affecting especially poor people. This study was aimed at assessing the role of Siyazondla homestead food production programme in food security and poverty alleviation in selected communities of Nkonkobe local municipality of the Eastern Cape. It took the form of a case study in Msobomvu, Ngcothoyi and Binfield locations. The Nkonkobe local municipality is demarcated into five major areas: Middledrift, Alice, Seymour, Fort Beaufort and Balfour. The study sample was collected from beneficiaries and non-beneficiaries of the Siyazondla programme. The sample size was 90 respondents, from which in one area, a 15 beneficiaries and anticipated non- beneficiaries were targeted. The target sample from each village was collected from 15 beneficiaries and non-beneficiaries. Many farmers from the study area benefited from the programme, though a limited number was targeted. Therefore, a probability sampling was applied and employed, where there were more than required number of beneficiaries of the programme and anticipated beneficiaries of the programme. The study was effectively and efficiently carried out and achieved with the use of personal interviewing of the recipients by use of questionnaires. The study was analysed by a computerised programme of analyses called SPSS v.2.1 and excel. The objectives of the study based on food security, poverty alleviation and reduction, and also improving nutritious status. The finding of the research clearly indicates the outcome of the programme on livelihood basis of the beneficiaries. Some of the objectives of the programme were achieved, such as food security and nutritious levels, whilst other objectives had shortcomings. The finding of the study also shows that programme, though had original benefits but also there are the anticipated and probable benefits of the programme Siyazondla, such as income, skill of farming, improving social status, and there are some possibilities when the programme is properly implemented. Though the majority of people are concentrated in rural areas, the programme on its own had shortcoming to meet needs of the whole population, as food insecurity, unemployment and poverty are taking its course. The programme on its own had shortcoming such as lack of adequate resource and as results, very few people benefited from the programme. Another shortcoming of the programme is the effectiveness of agricultural extension personnel to certain aspect such as marketing of farmers produce and proper monitoring and evaluation of the programme. Therefore, in the long run programmes of this nature are promising, there will be some development and improvement toward growth and better standards of livelihood. It is through this study that had to assess the structure, procedure, strategies implemented of the programme and impact of the programme to both beneficiaries and anticipated beneficiaries of the programme.
- Full Text:
- Date Issued: 2016
Active Layer Dynamics at Four Borehole Sites in Western Dronning Maud Land, Antarctica
- Authors: Kotzé, Camilla
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4894 , http://hdl.handle.net/10962/d1021295
- Description: Permafrost and active layer dynamics in the Antarctic play an important role within terrestrial landscapes and ecosystems and as a climate change indicator. However, they remain less thoroughly researched than their Northern-Hemispheric counterpart. Despite advancements made by ANTPAS on the permafrost and active layer monitoring network in the Antarctic, observational gaps still exist. Western Dronning Maud Land (WDML) has been identified as one of these gaps, necessitating further research on permafrost dynamics and the influence of climate parameters thereon. Such elucidation is critical to both the cryospheric and life sciences. Variations in the surface climate of Antarctica can be seen as a result of inter-annual variations in atmospheric circulation, enhancing permafrost degradation and active layer thickening which directly affects soil processes, such as sorting and cryoturbation. Ground temperatures from four permafrost boreholes from WDML were analysed from 2007 to 2014. The study sites exhibit seasonal freezing, periglacial landforms, and altitudinal variation, ranging between ca. 450masl to ca. 1300masl. Using ground thermal regime and regional climate data, the spatial and temporal variability of the active layer in the Ahlmannryggen and Jutulsessen areas of WDML were characterised. 137 Cs tracing has revealed that the active layer and associated landforms have been active over the past half century. Further results show that active layer depths at each site vary inter-annually and are particularly influenced by snow cover, altitude and distance to the ice-shelf. Moreover, a correlation between the SAO (Semi-Annual Oscillation) and measured ground temperatures was found, principally during the transitional season of the SAO in May and September. The relationship between climate and ground thermal regimes, especially the influence of teleconnections thereon, is essential to improving the understanding of permafrost dynamics and landform morphology in continental Antarctica.
- Full Text:
- Date Issued: 2016
- Authors: Kotzé, Camilla
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4894 , http://hdl.handle.net/10962/d1021295
- Description: Permafrost and active layer dynamics in the Antarctic play an important role within terrestrial landscapes and ecosystems and as a climate change indicator. However, they remain less thoroughly researched than their Northern-Hemispheric counterpart. Despite advancements made by ANTPAS on the permafrost and active layer monitoring network in the Antarctic, observational gaps still exist. Western Dronning Maud Land (WDML) has been identified as one of these gaps, necessitating further research on permafrost dynamics and the influence of climate parameters thereon. Such elucidation is critical to both the cryospheric and life sciences. Variations in the surface climate of Antarctica can be seen as a result of inter-annual variations in atmospheric circulation, enhancing permafrost degradation and active layer thickening which directly affects soil processes, such as sorting and cryoturbation. Ground temperatures from four permafrost boreholes from WDML were analysed from 2007 to 2014. The study sites exhibit seasonal freezing, periglacial landforms, and altitudinal variation, ranging between ca. 450masl to ca. 1300masl. Using ground thermal regime and regional climate data, the spatial and temporal variability of the active layer in the Ahlmannryggen and Jutulsessen areas of WDML were characterised. 137 Cs tracing has revealed that the active layer and associated landforms have been active over the past half century. Further results show that active layer depths at each site vary inter-annually and are particularly influenced by snow cover, altitude and distance to the ice-shelf. Moreover, a correlation between the SAO (Semi-Annual Oscillation) and measured ground temperatures was found, principally during the transitional season of the SAO in May and September. The relationship between climate and ground thermal regimes, especially the influence of teleconnections thereon, is essential to improving the understanding of permafrost dynamics and landform morphology in continental Antarctica.
- Full Text:
- Date Issued: 2016
An analysis of the efficiency of ontology and symbolic learning algorithms in indigenous knowledge representation
- Authors: Dzimba, Jesman
- Date: 2016
- Subjects: Ontology Computer algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/11939 , vital:39120
- Description: It is without a doubt that machine learning has been the area of focus in early days of artificial intelligence, but the early neural networks approach suffered some shortcomings and this led to a temporary decline in research capacity. New symbolic learning techniques have emerged since then which have yielded promising results and have led to a revival in research in machine learning. This has seen many researchers focusing on these techniques and experimenting with them by comparing their performances for different applications. With that in mind, the research thus decided to make an analysis of the symbolic approach against other approaches such as the neural network (connectionist) to evaluate the power of the former approach. This was done by first generating an ontology that acted as a representation of some collected indigenous knowledge. It is from this ontology that a dataset was generated. The dataset was made ambiguous to see the learning power of classifiers in such data. Two experiments were done, one using WEKA and the other using Orange as tools. The reason why the two experiments were used is because there was not a single tool which contained all the required learning algorithms. The research wanted to make use of ID3 and CN2 symbolic algorithm. However, WEKA had ID3 and not CN2 while Orange had CN2 and not ID3. The most important attributes from the ontology regarding the indigenous knowledge were the name of the plant, the province it is found and the disease the plant treats. Therefore the dataset had two features which were disease and province and one label which was the name of the plant. The learning algorithm was to use the two features to generate rules used to predict the label. However, there was ambiguity on the dataset. The challenge was that two different labels would contain the same features, thus leading to wrongful classification. This was the core of the research. Even though the learning model concluded this situation as wrongful classification, in real time, a system using the same learning model would provide desired and correct results. The only flow which was there is that the learning model simply used one label to predict under and ignore the other label with similar features. This was identified as a flow for both symbolic and non-symbolic algorithms. There is no way of giving suggestions in the case a user wants a different plant but with similar features. Therefore for classification using an ambiguous dataset, both these approaches proved to have the fore mentions flow. The research then decided to use recall to analyze the power of these approaches. It was discovered that ID3 has better recall than Multilayer perceptron and Naïve Bayes algorithms when using a training set. ID3 managed to recall clearly and effectively three of its classes by a probability of 1 while Bayes Net had only one class with recall probability of 1. To further investigate the issue of recall, cross validation was used to contrast the competence of recall of the three algorithms to strengthen the assertion that indeed ID3 has a better recall as compared to the other two algorithms. Three stages of cross-validation were done, one stage using 10 fold, the other 20 fold, and the last using 50 fold. For all the different stages of crossvalidation, Bayes Net proved to perform better in terms of recall than the other two algorithms. In cross-validation, MLP could recall approximately above 88% of the instances available in contrast to when using training set where the algorithm recall only two out of 18 instances. In overall the symbolic approach proved to be a commendable approach for use over the nonsymbolic approach. The study of machine learning involves the building of learning algorithms, improving upon learning algorithms or making comparisons of machine learning algorithms. The research raised awareness on some improvements that need to be done on not only symbolic algorithms but non-symbolic ones as well. Some improvements include improving on or coming up with algorithms that suggest alternative predictions in cases of ambiguity instead of doing wrongful classification and not reflect on other possibilities.
- Full Text:
- Date Issued: 2016
- Authors: Dzimba, Jesman
- Date: 2016
- Subjects: Ontology Computer algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/11939 , vital:39120
- Description: It is without a doubt that machine learning has been the area of focus in early days of artificial intelligence, but the early neural networks approach suffered some shortcomings and this led to a temporary decline in research capacity. New symbolic learning techniques have emerged since then which have yielded promising results and have led to a revival in research in machine learning. This has seen many researchers focusing on these techniques and experimenting with them by comparing their performances for different applications. With that in mind, the research thus decided to make an analysis of the symbolic approach against other approaches such as the neural network (connectionist) to evaluate the power of the former approach. This was done by first generating an ontology that acted as a representation of some collected indigenous knowledge. It is from this ontology that a dataset was generated. The dataset was made ambiguous to see the learning power of classifiers in such data. Two experiments were done, one using WEKA and the other using Orange as tools. The reason why the two experiments were used is because there was not a single tool which contained all the required learning algorithms. The research wanted to make use of ID3 and CN2 symbolic algorithm. However, WEKA had ID3 and not CN2 while Orange had CN2 and not ID3. The most important attributes from the ontology regarding the indigenous knowledge were the name of the plant, the province it is found and the disease the plant treats. Therefore the dataset had two features which were disease and province and one label which was the name of the plant. The learning algorithm was to use the two features to generate rules used to predict the label. However, there was ambiguity on the dataset. The challenge was that two different labels would contain the same features, thus leading to wrongful classification. This was the core of the research. Even though the learning model concluded this situation as wrongful classification, in real time, a system using the same learning model would provide desired and correct results. The only flow which was there is that the learning model simply used one label to predict under and ignore the other label with similar features. This was identified as a flow for both symbolic and non-symbolic algorithms. There is no way of giving suggestions in the case a user wants a different plant but with similar features. Therefore for classification using an ambiguous dataset, both these approaches proved to have the fore mentions flow. The research then decided to use recall to analyze the power of these approaches. It was discovered that ID3 has better recall than Multilayer perceptron and Naïve Bayes algorithms when using a training set. ID3 managed to recall clearly and effectively three of its classes by a probability of 1 while Bayes Net had only one class with recall probability of 1. To further investigate the issue of recall, cross validation was used to contrast the competence of recall of the three algorithms to strengthen the assertion that indeed ID3 has a better recall as compared to the other two algorithms. Three stages of cross-validation were done, one stage using 10 fold, the other 20 fold, and the last using 50 fold. For all the different stages of crossvalidation, Bayes Net proved to perform better in terms of recall than the other two algorithms. In cross-validation, MLP could recall approximately above 88% of the instances available in contrast to when using training set where the algorithm recall only two out of 18 instances. In overall the symbolic approach proved to be a commendable approach for use over the nonsymbolic approach. The study of machine learning involves the building of learning algorithms, improving upon learning algorithms or making comparisons of machine learning algorithms. The research raised awareness on some improvements that need to be done on not only symbolic algorithms but non-symbolic ones as well. Some improvements include improving on or coming up with algorithms that suggest alternative predictions in cases of ambiguity instead of doing wrongful classification and not reflect on other possibilities.
- Full Text:
- Date Issued: 2016
An assessment of participatory development and rural sustainable livelihoods in Zimbabwe : the case of Tsholotsho District
- Authors: Moyo, Walter Ntandoyenkosi
- Date: 2016
- Subjects: Community development -- Zimbabwe Rural development projects -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8419 , vital:32744
- Description: The central merits of this study and of the efforts invested throughout its development lie in its focus on participatory development and rural sustainable livelihoods. The main objective of the study was to assess the implementation of development projects in Tsholotsho district in Zimbabwe with regards to the issue of participation and its role to sustainable development. The study utilised the documentary research methodology which was used to gather data. The analysis of data was undertaken through the use of the participatory approach as the main theoretical framework. The study has shown that participatory development has been altered to take numerous and divergent forms that do not usher in the expected outcomes. Participatory development in Tsholotsho has thus taken a different stance since it has turned to be merely rhetoric and has suffered modifications and transformations to such an extent that power relations between and among development stakeholders subjugate the poor further leaving them without any voice. Community members are experiencing a ritual of empty processes that camouflage as participatory development making the people not to be centrally involved in bringing about rural sustainable development. One of the greatest challenges facing the rural development domain today is the search for alternative tools that seek to facilitate collective actions and solutions through the process of participation so that the poor get to be active not passive agents of development. This study is of the view that more research is needed to study the indigenous rural knowledge systems and their integration to modern knowledge systems; more so that is also a need to scrutinize the roles and responsibilities of NGOs interventions since they have made significant impacts in rural development. Finally, there is need to assess how policies affect development providers’ contributions in development processes.
- Full Text:
- Date Issued: 2016
- Authors: Moyo, Walter Ntandoyenkosi
- Date: 2016
- Subjects: Community development -- Zimbabwe Rural development projects -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8419 , vital:32744
- Description: The central merits of this study and of the efforts invested throughout its development lie in its focus on participatory development and rural sustainable livelihoods. The main objective of the study was to assess the implementation of development projects in Tsholotsho district in Zimbabwe with regards to the issue of participation and its role to sustainable development. The study utilised the documentary research methodology which was used to gather data. The analysis of data was undertaken through the use of the participatory approach as the main theoretical framework. The study has shown that participatory development has been altered to take numerous and divergent forms that do not usher in the expected outcomes. Participatory development in Tsholotsho has thus taken a different stance since it has turned to be merely rhetoric and has suffered modifications and transformations to such an extent that power relations between and among development stakeholders subjugate the poor further leaving them without any voice. Community members are experiencing a ritual of empty processes that camouflage as participatory development making the people not to be centrally involved in bringing about rural sustainable development. One of the greatest challenges facing the rural development domain today is the search for alternative tools that seek to facilitate collective actions and solutions through the process of participation so that the poor get to be active not passive agents of development. This study is of the view that more research is needed to study the indigenous rural knowledge systems and their integration to modern knowledge systems; more so that is also a need to scrutinize the roles and responsibilities of NGOs interventions since they have made significant impacts in rural development. Finally, there is need to assess how policies affect development providers’ contributions in development processes.
- Full Text:
- Date Issued: 2016
An assessment of quality, class and grade of service (QoS, CoS and GoS) over worldwide interoperability for microwave access (WiMax) networks through performance evaluation of bandwidth
- Authors: Nomnga, Phumzile
- Date: 2016
- Subjects: Wireless communication systems Wireless LANs -- Standards Broadband communication systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8033 , vital:31481
- Description: The Dwesa WiMAX network provides broadband communications over wireless connectivity for various types of multimedia traffic, such as emailing, browsing, VoIP, file transfer, etc. to the community members. The community members of Dwesa use schools’ computer labs to access the network and generate the aforementioned multimedia packets on dedicated timeslots and thus cause network congestion during such timeslots. Against this background, WiMAX implementation has faced several challenges in living up to its objectives in RMAs. Quality of Service (QoS) degradation as a result of high traffic demands remains one of the challenges thwarting WiMAX implementation. The GoS is also bound to get compromised as connectivity demands arise consistently with more subscribers connecting to the network, making it difficult to measure the success a subscriber is expected to have in accessing the network. The CoS and SchedType play a significant role in the redistribution of the available bandwidth to all bandwidth requests. This research project exploits this avenue to assess the resultant degradation of QoS and GoS caused by the inconsistent availability of bandwidth as redistributed by the CoS combination with a SchedType. The four CoS which are, namely, the UGS, rtPS, nrtPS and BE were implemented with the different SchedTypes, namely, MBQOS, FCFS and rtPS. Although the implementation process was conducted in a simulated environment using NS-3, the simulated network emulated the network setup implemented in Dwesa. The outcomes of the implementation suggests that certain combinations of the CoS’s with SchedTypes can lead to degradation of QoS whilst some combinations can redistribute the available bandwidth to ensure the provisioning of guaranteed QoS.
- Full Text:
- Date Issued: 2016
- Authors: Nomnga, Phumzile
- Date: 2016
- Subjects: Wireless communication systems Wireless LANs -- Standards Broadband communication systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8033 , vital:31481
- Description: The Dwesa WiMAX network provides broadband communications over wireless connectivity for various types of multimedia traffic, such as emailing, browsing, VoIP, file transfer, etc. to the community members. The community members of Dwesa use schools’ computer labs to access the network and generate the aforementioned multimedia packets on dedicated timeslots and thus cause network congestion during such timeslots. Against this background, WiMAX implementation has faced several challenges in living up to its objectives in RMAs. Quality of Service (QoS) degradation as a result of high traffic demands remains one of the challenges thwarting WiMAX implementation. The GoS is also bound to get compromised as connectivity demands arise consistently with more subscribers connecting to the network, making it difficult to measure the success a subscriber is expected to have in accessing the network. The CoS and SchedType play a significant role in the redistribution of the available bandwidth to all bandwidth requests. This research project exploits this avenue to assess the resultant degradation of QoS and GoS caused by the inconsistent availability of bandwidth as redistributed by the CoS combination with a SchedType. The four CoS which are, namely, the UGS, rtPS, nrtPS and BE were implemented with the different SchedTypes, namely, MBQOS, FCFS and rtPS. Although the implementation process was conducted in a simulated environment using NS-3, the simulated network emulated the network setup implemented in Dwesa. The outcomes of the implementation suggests that certain combinations of the CoS’s with SchedTypes can lead to degradation of QoS whilst some combinations can redistribute the available bandwidth to ensure the provisioning of guaranteed QoS.
- Full Text:
- Date Issued: 2016
An assessment of the efficiency and effectiveness of the Working for Water NBAL mapping, contract teams and clearing of Acacia mearnsii
- Authors: Modipa, Rebone Dineo
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3192 , vital:20383
- Description: Working for Water (WfW) works to fulfil their dual mandate of protecting ecosystem services and creating employment opportunities for poor communities. There have been many successes but evidence is increasing regarding the inefficiencies at project and site scales. The study was undertaken in the Eastern Cape, South Africa, at a farm called Ann’s Villa situated in the Kommadagga valley, at the foot of the northern side of the Zuurberg pass. The study sought to assess the efficiency of the WfW mapping of natural biological aliens (NBAL), of contract teams and the effectiveness of the clearing methods employed to clear Acacia mearnsii. To achieve this, WfW mapping was analysed, contract team dynamics of the different task groups were observed and assessed and various Acacia mearnsii and indigenous plant variables were measured pre-and post-clearing of A. mearnsii. The first key finding was that overall the WfW NBAL mapping was inaccurate, with WfW A. mearnsii percentage cover (cover) estimations significantly over-estimated. Acacia mearnsii cover over-estimations resulted in fruitless expenditure as contracts were more expensive than necessary. Cover under-estimations also led to the inability to fulfill contractual obligations and the subsequent halting of the clearing of a large portion the study area. It was recommended that the NBAL mapping as well as the cover estimations of NBALs be conducted more rigorously, with expert assistance where skills are lacking, to avoid the associated fruitless expenditure. The second key finding was that WfW contract teams were largely inefficient, as a result of waiting, stemming from the lack of continuity in work. There was a strong positive relationship between subgroup chainsaw operator (CO) to stacker ratio and subgroup CO to stacker efficiency ratio. These inefficiencies meant that a mean of 58±67% of the total money spent per team resulted in fruitless expenditure. It was recommend that contract teams be organised to promote the continuity of work and that the current high stacker to CO ratios be reversed to increase efficiency and reduce fruitless expenditures. The third key finding was that overall the WfW methods of clearing A. mearnsii were 95% effective with a 90% removal success. The last key finding was that initial clearing operations had a largely insignificant impact on indigenous plant biodiversity. It was recommended that post-clearing inspection of quality control is conducted more rigorously and that penalties be implemented to deter contract teams from cutting indigenous species.
- Full Text:
- Date Issued: 2016
- Authors: Modipa, Rebone Dineo
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3192 , vital:20383
- Description: Working for Water (WfW) works to fulfil their dual mandate of protecting ecosystem services and creating employment opportunities for poor communities. There have been many successes but evidence is increasing regarding the inefficiencies at project and site scales. The study was undertaken in the Eastern Cape, South Africa, at a farm called Ann’s Villa situated in the Kommadagga valley, at the foot of the northern side of the Zuurberg pass. The study sought to assess the efficiency of the WfW mapping of natural biological aliens (NBAL), of contract teams and the effectiveness of the clearing methods employed to clear Acacia mearnsii. To achieve this, WfW mapping was analysed, contract team dynamics of the different task groups were observed and assessed and various Acacia mearnsii and indigenous plant variables were measured pre-and post-clearing of A. mearnsii. The first key finding was that overall the WfW NBAL mapping was inaccurate, with WfW A. mearnsii percentage cover (cover) estimations significantly over-estimated. Acacia mearnsii cover over-estimations resulted in fruitless expenditure as contracts were more expensive than necessary. Cover under-estimations also led to the inability to fulfill contractual obligations and the subsequent halting of the clearing of a large portion the study area. It was recommended that the NBAL mapping as well as the cover estimations of NBALs be conducted more rigorously, with expert assistance where skills are lacking, to avoid the associated fruitless expenditure. The second key finding was that WfW contract teams were largely inefficient, as a result of waiting, stemming from the lack of continuity in work. There was a strong positive relationship between subgroup chainsaw operator (CO) to stacker ratio and subgroup CO to stacker efficiency ratio. These inefficiencies meant that a mean of 58±67% of the total money spent per team resulted in fruitless expenditure. It was recommend that contract teams be organised to promote the continuity of work and that the current high stacker to CO ratios be reversed to increase efficiency and reduce fruitless expenditures. The third key finding was that overall the WfW methods of clearing A. mearnsii were 95% effective with a 90% removal success. The last key finding was that initial clearing operations had a largely insignificant impact on indigenous plant biodiversity. It was recommended that post-clearing inspection of quality control is conducted more rigorously and that penalties be implemented to deter contract teams from cutting indigenous species.
- Full Text:
- Date Issued: 2016
An assessment of the invasion state and fisheries suitability in four dams and a natural lake in the Western Cape, South Africa
- Authors: Dredge, Brendon Neville
- Date: 2016
- Subjects: Introduced organisms Fishery management -- South Africa -- Western Cape Fishes -- Conservation -- South Africa -- Western Cape Introduced fishes -- South Africa -- Western Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/69114 , vital:29391
- Description: Despite more than a century of introductions, fish invasions are poorly understood in South Africa. This thesis aims to: (1) provide baseline information on the fish fauna in five inland water bodies (four dams: Theewaterskloof, Clanwilliam, Quaggaskloof, and Voelvlei and a natural lake, Groenvlei) in the Western Cape; (2) determine which species were established and provide a baseline of abundance and size structure for monitoring and, (3) make preliminary recommendations for a fishery. First, criteria for determining establishment were developed by undertaking a full biological assessment of bluegill Lepomis macrochirus, a data-poor species in South Africa. This included the assessment of growth rate using validated estimates of age derived from otoliths in two dams (Clanwilliam Dam: Lt=335.9(1−eo.113(t+1.06)); Groenvlei: Lt=287.2(1-e−0.171(t+0.54)). Length at 50% maturity was similar for males (146 mmFL) and females (147 mmFL). Length frequency analysis combined with data on the age and growth and reproduction demonstrated that established populations of bluegill contained several age cohorts as well as mature and juvenile fishes. A meta-analysis was conducted to: (1) compile a list of initial stocking dates for all alien fishes in each waterbody and (2) use angler tournament data to assess for additional species and persistence over time. Data from the meta-analysis was combined with ichthyological survey data to determine establishment success. These data demonstrated that nine non-native species had established in the five water bodies. Clanwilliam Dam had the largest number (7) of non-native species established, Groenvlei (5) and Theewaterskloof, Brandvlei and Voelvlei the lowest with four species. The state of invasion of each species in the province showed that all nine species are categorised as invasive. This information on establishment was then integrated into a framework for rapidly determining what type of fishery would be most suitable for the 5 waterbodies. Potential yield was estimated using morphoedaphic models, were 260 t/yr for Theewaterskloof Dam, 93 t/yr for Voelvlei, 81 t/yr for Brandvlei, 59 t/yr for Groenvlei and 55 t/yr for Groenvlei. The CPUE for Groenvlei was the highest in gill nets with 1.32 ± 1.94 kg/h, then Voelvlei 1.05 ± 1.34 kg/h followed by Brandvlei (0.84 ± 1.48 kg/h), Clanwilliam (0.71 ± 1.55 kg/h) and lastly Theewaterskloof (0.36 ± 0.41 kg/h). Only Theewaterskloof could produce in excess of 100 t/yr but less than 400 t/yr of fish making it suitable for a small scale fishery. The CPUE values of Theewaterskloof were the lowest and a gill net fishery on this water body may not produce sufficient fish for the fishery. All water bodies had a high recreational angling usage, the opening of a small scale fishery could be detrimental to this industry. Subsistence and recreational anglers should be promoted with the possibility of a long line industry targeting Clarias gariepinus.
- Full Text:
- Date Issued: 2016
- Authors: Dredge, Brendon Neville
- Date: 2016
- Subjects: Introduced organisms Fishery management -- South Africa -- Western Cape Fishes -- Conservation -- South Africa -- Western Cape Introduced fishes -- South Africa -- Western Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/69114 , vital:29391
- Description: Despite more than a century of introductions, fish invasions are poorly understood in South Africa. This thesis aims to: (1) provide baseline information on the fish fauna in five inland water bodies (four dams: Theewaterskloof, Clanwilliam, Quaggaskloof, and Voelvlei and a natural lake, Groenvlei) in the Western Cape; (2) determine which species were established and provide a baseline of abundance and size structure for monitoring and, (3) make preliminary recommendations for a fishery. First, criteria for determining establishment were developed by undertaking a full biological assessment of bluegill Lepomis macrochirus, a data-poor species in South Africa. This included the assessment of growth rate using validated estimates of age derived from otoliths in two dams (Clanwilliam Dam: Lt=335.9(1−eo.113(t+1.06)); Groenvlei: Lt=287.2(1-e−0.171(t+0.54)). Length at 50% maturity was similar for males (146 mmFL) and females (147 mmFL). Length frequency analysis combined with data on the age and growth and reproduction demonstrated that established populations of bluegill contained several age cohorts as well as mature and juvenile fishes. A meta-analysis was conducted to: (1) compile a list of initial stocking dates for all alien fishes in each waterbody and (2) use angler tournament data to assess for additional species and persistence over time. Data from the meta-analysis was combined with ichthyological survey data to determine establishment success. These data demonstrated that nine non-native species had established in the five water bodies. Clanwilliam Dam had the largest number (7) of non-native species established, Groenvlei (5) and Theewaterskloof, Brandvlei and Voelvlei the lowest with four species. The state of invasion of each species in the province showed that all nine species are categorised as invasive. This information on establishment was then integrated into a framework for rapidly determining what type of fishery would be most suitable for the 5 waterbodies. Potential yield was estimated using morphoedaphic models, were 260 t/yr for Theewaterskloof Dam, 93 t/yr for Voelvlei, 81 t/yr for Brandvlei, 59 t/yr for Groenvlei and 55 t/yr for Groenvlei. The CPUE for Groenvlei was the highest in gill nets with 1.32 ± 1.94 kg/h, then Voelvlei 1.05 ± 1.34 kg/h followed by Brandvlei (0.84 ± 1.48 kg/h), Clanwilliam (0.71 ± 1.55 kg/h) and lastly Theewaterskloof (0.36 ± 0.41 kg/h). Only Theewaterskloof could produce in excess of 100 t/yr but less than 400 t/yr of fish making it suitable for a small scale fishery. The CPUE values of Theewaterskloof were the lowest and a gill net fishery on this water body may not produce sufficient fish for the fishery. All water bodies had a high recreational angling usage, the opening of a small scale fishery could be detrimental to this industry. Subsistence and recreational anglers should be promoted with the possibility of a long line industry targeting Clarias gariepinus.
- Full Text:
- Date Issued: 2016
An assessment of the small-scale fisheries in the Kogelberg district of the Western Cape, South Africa
- Authors: Jordan, Tia
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/997 , vital:20011
- Description: Small-scale fisheries play a critical role in communities by contributing to food security, poverty alleviation and source of income. The study focused on the Kleinmond small-scale fishery and estimated the current economic value of the fishery as well as exploring the potential for increasing this and also whether it is being used in a way that ensures sustainable harvesting of the marine resources. It was important to evaluate the ecological, economic and social dimensions of the fishing community in order to address the problems currently facing the community. The study draws on previous research done in the Kleinmond area. Data were collected to update and complement previous research and addresses current research. In order to investigate the fisheries catch contribution in the area, data were obtained from the Department of Agriculture, Forestry and Fisheries. Three different questionnaires were developed and conducted in face-to-face formal and informal interviews with the various stakeholders (n=42) in the value-chain. Interviews were also conducted telephonically with other stakeholders and a focus group was formed to supplement previous available data. Simple economic models were developed for the fisheries working from the Kleinmond harbour, which were used to estimate the gross and net economic value of catches for individual right-holders, as well as the Kleinmond area as a whole. The economic models used in this study showed that the West Coast rock lobster Jasus lalandii, fishery was the primary source of income for small-scale fishers. This was due to the rock lobsters being sold to the export market as a high-valued commodity, whereas the linefish were sold to the local market as a lower-valued commodity. However, linefish were found to be more of a commodity to the community as a portion would be retained for personal consumption. The linefishers were concerned in that over the past couple of years, snoek Thrysites atun have been absent the Kleinmond area, resulting in and the fishing effort shifting to a resident species Cape bream Pachymetopon blochii. Whereas West Coast rock lobster were considered to be harvested sustainably under the current total allowable catch strategy, there was concern for the future of the fishery because of the occurrence of illegal fishing, both locally and nationally. Small-scale fisheries in the Kleinmond community are largely dependent on fishing resources, even though the industry is only marginally profitable. Future management measures should concentrate on optimising the value-chain to provide both sustainability for the resources and improve the livelihoods of the community.
- Full Text:
- Date Issued: 2016
- Authors: Jordan, Tia
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/997 , vital:20011
- Description: Small-scale fisheries play a critical role in communities by contributing to food security, poverty alleviation and source of income. The study focused on the Kleinmond small-scale fishery and estimated the current economic value of the fishery as well as exploring the potential for increasing this and also whether it is being used in a way that ensures sustainable harvesting of the marine resources. It was important to evaluate the ecological, economic and social dimensions of the fishing community in order to address the problems currently facing the community. The study draws on previous research done in the Kleinmond area. Data were collected to update and complement previous research and addresses current research. In order to investigate the fisheries catch contribution in the area, data were obtained from the Department of Agriculture, Forestry and Fisheries. Three different questionnaires were developed and conducted in face-to-face formal and informal interviews with the various stakeholders (n=42) in the value-chain. Interviews were also conducted telephonically with other stakeholders and a focus group was formed to supplement previous available data. Simple economic models were developed for the fisheries working from the Kleinmond harbour, which were used to estimate the gross and net economic value of catches for individual right-holders, as well as the Kleinmond area as a whole. The economic models used in this study showed that the West Coast rock lobster Jasus lalandii, fishery was the primary source of income for small-scale fishers. This was due to the rock lobsters being sold to the export market as a high-valued commodity, whereas the linefish were sold to the local market as a lower-valued commodity. However, linefish were found to be more of a commodity to the community as a portion would be retained for personal consumption. The linefishers were concerned in that over the past couple of years, snoek Thrysites atun have been absent the Kleinmond area, resulting in and the fishing effort shifting to a resident species Cape bream Pachymetopon blochii. Whereas West Coast rock lobster were considered to be harvested sustainably under the current total allowable catch strategy, there was concern for the future of the fishery because of the occurrence of illegal fishing, both locally and nationally. Small-scale fisheries in the Kleinmond community are largely dependent on fishing resources, even though the industry is only marginally profitable. Future management measures should concentrate on optimising the value-chain to provide both sustainability for the resources and improve the livelihoods of the community.
- Full Text:
- Date Issued: 2016
An erosion and sediment delivery model for semi-arid catchments
- Authors: Bryson, Louise Kay
- Date: 2016
- Subjects: Sedimentation and deposition , Erosion , Watershed management -- South Africa , Water-supply -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6056 , http://hdl.handle.net/10962/d1020331
- Description: Sedimentation has become a significant environmental threat in South Africa as it intensifies water management problems in the water-scarce semi-arid regions of the country. As South Africa already allocates 98% of available water, the loss of storage capacity in reservoirs and degraded water quality has meant that a reliable water supply is compromised. The overall aim of this thesis was to develop a catchment scale model that represents the sediment dynamics of semi-arid regions of South Africa as a simple and practically applicable tool for water resource managers. Development of a conceptual framework for the model relied on an understanding of both the sediment dynamics of South African catchments and applicable modelling techniques. Scale was an issue in both cases as most of our understanding of the physical processes of runoff generation and sediment transport has been derived from plot scale studies. By identifying defining properties of semi-arid catchments it was possible to consider how temporal and spatial properties at higher levels emerged from properties at lower levels. These properties were effectively represented by using the Pitman rainfall-runoff model disaggregated to a daily timescale, the Modified Universal Soil Loss Equation (MUSLE) model incorporating probability function theory and through the representation of sediment storages across a semi-distributed catchment. The model was tested on two small and one large study catchment in the Karoo, South Africa, with limited observed data. Limitations to the model were found to be the large parameter data set and the dominance of structural constraints with an increase in catchment size. The next steps in model development will require a reduction of the parameter data set and an inclusion of an in-stream component for sub-catchments at a larger spatial scale. The model is applicable in areas such as South Africa where water resource managers need a simple model at the catchment scale in order to make decisions. This type of model provides a simple representation of the stochastic nature of erosion and sediment delivery over large spatial and temporal scales.
- Full Text:
- Date Issued: 2016
- Authors: Bryson, Louise Kay
- Date: 2016
- Subjects: Sedimentation and deposition , Erosion , Watershed management -- South Africa , Water-supply -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6056 , http://hdl.handle.net/10962/d1020331
- Description: Sedimentation has become a significant environmental threat in South Africa as it intensifies water management problems in the water-scarce semi-arid regions of the country. As South Africa already allocates 98% of available water, the loss of storage capacity in reservoirs and degraded water quality has meant that a reliable water supply is compromised. The overall aim of this thesis was to develop a catchment scale model that represents the sediment dynamics of semi-arid regions of South Africa as a simple and practically applicable tool for water resource managers. Development of a conceptual framework for the model relied on an understanding of both the sediment dynamics of South African catchments and applicable modelling techniques. Scale was an issue in both cases as most of our understanding of the physical processes of runoff generation and sediment transport has been derived from plot scale studies. By identifying defining properties of semi-arid catchments it was possible to consider how temporal and spatial properties at higher levels emerged from properties at lower levels. These properties were effectively represented by using the Pitman rainfall-runoff model disaggregated to a daily timescale, the Modified Universal Soil Loss Equation (MUSLE) model incorporating probability function theory and through the representation of sediment storages across a semi-distributed catchment. The model was tested on two small and one large study catchment in the Karoo, South Africa, with limited observed data. Limitations to the model were found to be the large parameter data set and the dominance of structural constraints with an increase in catchment size. The next steps in model development will require a reduction of the parameter data set and an inclusion of an in-stream component for sub-catchments at a larger spatial scale. The model is applicable in areas such as South Africa where water resource managers need a simple model at the catchment scale in order to make decisions. This type of model provides a simple representation of the stochastic nature of erosion and sediment delivery over large spatial and temporal scales.
- Full Text:
- Date Issued: 2016
An evaluation of medicinal plants used in South Africa and Lesotho for uterotonic contractile purposes
- Authors: Smit, Inge
- Date: 2016
- Subjects: Traditional medicine -- South Africa Traditional medicine -- Lesotho
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15232 , vital:40256
- Description: Background One of the leading cause of maternal mortality globally is postpartum haemorrhage (PPH), which mainly occur in developing countries. By identifying traditional medicinal plants that is used by Traditional birth attendants we can analysis the plants for cyclotides which contain uterotonic properties and a wide variety of other properties. The indigenous knowledge of traditional medicinal plants need to be preserved and scientifically proven to ensure future drug development and continued use of these plants. Cyclotides can be used as a backbone to develop novel drugs in that cyclotides are very stable proteins. Methods: Ten plants were identified that are commonly used to prevent or treat postpartum haemorrhage. The plant samples were collected, prepared and dried in South Africa. The plants were analysed in Austria. The plants underwent extraction of one gram of each plant was analysed using: Matrix-Assisted Laser desorption Ionization time-of-flight Mass Spectrometry (MALDI-TOF-MS); Tandem Mass Spectrometry and Analysis by High-performance Liquid Chromatography (HPLC). Results None of the ten plants analysed showed the presence of cyclotides. It is important to report negative results, because it informs the academic fraternity and could be entered in a global data base of results. The plants analysed is known to be used by Traditional Birth Attendants for the treatment or prevention of postpartum haemorrhage. Conclusion All the plants analysed are commonly used to prevent and treat PPH. The fact that no cyclotides were found do not dispute the practical use of these plants to prevent and treat PPH. There continue to be a gap in what uterotonic properties these plants contain and should be further investigated.
- Full Text:
- Date Issued: 2016
- Authors: Smit, Inge
- Date: 2016
- Subjects: Traditional medicine -- South Africa Traditional medicine -- Lesotho
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15232 , vital:40256
- Description: Background One of the leading cause of maternal mortality globally is postpartum haemorrhage (PPH), which mainly occur in developing countries. By identifying traditional medicinal plants that is used by Traditional birth attendants we can analysis the plants for cyclotides which contain uterotonic properties and a wide variety of other properties. The indigenous knowledge of traditional medicinal plants need to be preserved and scientifically proven to ensure future drug development and continued use of these plants. Cyclotides can be used as a backbone to develop novel drugs in that cyclotides are very stable proteins. Methods: Ten plants were identified that are commonly used to prevent or treat postpartum haemorrhage. The plant samples were collected, prepared and dried in South Africa. The plants were analysed in Austria. The plants underwent extraction of one gram of each plant was analysed using: Matrix-Assisted Laser desorption Ionization time-of-flight Mass Spectrometry (MALDI-TOF-MS); Tandem Mass Spectrometry and Analysis by High-performance Liquid Chromatography (HPLC). Results None of the ten plants analysed showed the presence of cyclotides. It is important to report negative results, because it informs the academic fraternity and could be entered in a global data base of results. The plants analysed is known to be used by Traditional Birth Attendants for the treatment or prevention of postpartum haemorrhage. Conclusion All the plants analysed are commonly used to prevent and treat PPH. The fact that no cyclotides were found do not dispute the practical use of these plants to prevent and treat PPH. There continue to be a gap in what uterotonic properties these plants contain and should be further investigated.
- Full Text:
- Date Issued: 2016
An evaluation of the morphological and genetic diversity of Eurydice occurring on South African sandy beaches
- Hawkins, Magdalena Johanna, Hauser, Lorenz
- Authors: Hawkins, Magdalena Johanna , Hauser, Lorenz
- Date: 2016
- Subjects: Morphology , Beaches -- Morphology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/6708 , vital:21128
- Description: This study evaluated the diversity of the genus Eurydice on sandy beaches in South Africa by analysis of morphological as well as genetic data. Type specimens of the three Eurydice species currently known from South Africa, E. longicornis, E. kensleyi and E. barnardi were obtained from the Museum für Naturkunde in Berlin and the Iziko Museum in Cape Town, South Africa. These specimens were studied in order to become familiar with their morphology. Eurydice individuals obtained from 30 sites spanning the South African coast, from Port Nolloth on the north-west coast to Bhanga Nek on the north-east coast were then examined. The two species E. kensleyi and E. barnardi, as well as four new morphospecies (A, B, C and D) were discriminated from these individuals by suites of morphological character types. Morphospecies A, B, C and D were therefore delimited according to the Phenetic Species Concept. None of the Eurydice individuals examined exhibited the same suite of characters as E. longicornis. Molecular sequences of two mitochondrial markers, cytochrome c oxidase 1 and 16S rRNA were analysed using both distance- and monophyly based methods. Uncorrected p-distances, a Minimum Spanning Haplotype Network and Maximum Likelihood phylogenetic trees were investigated to determine genetic diversity and phylogenetic relationships in the six Eurydice morphospecies. Results from the genetic analysis made it possible to delimit morphospecies A B, C and D as phylospecies A, B, C and D according to the Phylogenetic Species Concept, thereby validating the species status of four new Eurydice species, provisionally called Eurydice A, Eurydice B, Eurydice C and Eurydice D. This increases the total number of Eurydice species from South Africa to seven, of which six form part of the macrofauna of sandy beaches. The outcomes of this study represent an important step in the resolution of the taxonomy of the genus Eurydice in South Africa and enhance current knowledge of the biodiversity of sandy beach macrofauna, thus facilitating better-informed decisions on conservation policies and management to the benefit of conservation of biodiversity on sandy beaches in South Africa.
- Full Text:
- Date Issued: 2016
- Authors: Hawkins, Magdalena Johanna , Hauser, Lorenz
- Date: 2016
- Subjects: Morphology , Beaches -- Morphology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/6708 , vital:21128
- Description: This study evaluated the diversity of the genus Eurydice on sandy beaches in South Africa by analysis of morphological as well as genetic data. Type specimens of the three Eurydice species currently known from South Africa, E. longicornis, E. kensleyi and E. barnardi were obtained from the Museum für Naturkunde in Berlin and the Iziko Museum in Cape Town, South Africa. These specimens were studied in order to become familiar with their morphology. Eurydice individuals obtained from 30 sites spanning the South African coast, from Port Nolloth on the north-west coast to Bhanga Nek on the north-east coast were then examined. The two species E. kensleyi and E. barnardi, as well as four new morphospecies (A, B, C and D) were discriminated from these individuals by suites of morphological character types. Morphospecies A, B, C and D were therefore delimited according to the Phenetic Species Concept. None of the Eurydice individuals examined exhibited the same suite of characters as E. longicornis. Molecular sequences of two mitochondrial markers, cytochrome c oxidase 1 and 16S rRNA were analysed using both distance- and monophyly based methods. Uncorrected p-distances, a Minimum Spanning Haplotype Network and Maximum Likelihood phylogenetic trees were investigated to determine genetic diversity and phylogenetic relationships in the six Eurydice morphospecies. Results from the genetic analysis made it possible to delimit morphospecies A B, C and D as phylospecies A, B, C and D according to the Phylogenetic Species Concept, thereby validating the species status of four new Eurydice species, provisionally called Eurydice A, Eurydice B, Eurydice C and Eurydice D. This increases the total number of Eurydice species from South Africa to seven, of which six form part of the macrofauna of sandy beaches. The outcomes of this study represent an important step in the resolution of the taxonomy of the genus Eurydice in South Africa and enhance current knowledge of the biodiversity of sandy beach macrofauna, thus facilitating better-informed decisions on conservation policies and management to the benefit of conservation of biodiversity on sandy beaches in South Africa.
- Full Text:
- Date Issued: 2016
An insight into the profile characteristics and technical batting skill of adolescent cricket players
- Authors: Clark, Matthew Edward
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2838 , vital:20331
- Description: Background: Current traditional cricket practices incorporate the use of a netted-off pitch to provide cricket players the opportunity to hone their skills with bat and ball. The lack of ecological validity of these training environments results in the absence of important task and environmental constraints which influences the manner in which the sport is played. Objectives: The purpose of the current research was two-fold: firstly, it aimed to establish a profile database of adolescent cricket players in the Eastern Cape province of South Africa; and secondly, it aimed to investigate the efficacy of a constraints-led training intervention on skill development in adolescent cricket batsmen. Methods: Study I required 90 participants (u13: n = 40; u15: n = 50) to perform measures pertaining to anthropometric, morphological, flexibility and physical performance characteristics. This included stature, mass, body composition, limb length, flexibility, agility, and power measures. Study II was a case-control study (u15: n = 24), whereby the experimental group (n = 12) was exposed to a constraints-led batting protocol during the course of the cricket season. The objective of the protocol was to encourage the manipulation of the ball around the playing field. Pre- and post-intervention measures were performed using a batting skills test, which assessed batsmen’s capability to manipulate the ball to various areas of the playing field. Results: Study I revealed significant differences (p <0.0001) in stature, mass, limb length and power variables when comparing the u15 age group with the u13 age group. No differences were recorded for agility. The u13 age group had greater linear correlations for the variables of interest compared to the u15 age group. Study II revealed no differences in technical skill between the experimental group and the control (p <0.315).. The tests also revealed that adolescent batsmen favoured hitting deliveries through the extra-cover scoring zone. The third-man and fine-leg scoring zones were least preferred to hit deliveries through. A number of limitations to the study design resulted in the inability to determine the efficacy of a constraints-led batting protocol on skill development in an adolescent batting cohort. Conclusion: The results of study I indicated that the onset of puberty played an important role in the measures and performances between the u13 and u15 age groups. The results of study II indicated that adolescent batsmen are not adept at manipulating the ball around the field. Recommendations are provided for both studies.
- Full Text:
- Date Issued: 2016
- Authors: Clark, Matthew Edward
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2838 , vital:20331
- Description: Background: Current traditional cricket practices incorporate the use of a netted-off pitch to provide cricket players the opportunity to hone their skills with bat and ball. The lack of ecological validity of these training environments results in the absence of important task and environmental constraints which influences the manner in which the sport is played. Objectives: The purpose of the current research was two-fold: firstly, it aimed to establish a profile database of adolescent cricket players in the Eastern Cape province of South Africa; and secondly, it aimed to investigate the efficacy of a constraints-led training intervention on skill development in adolescent cricket batsmen. Methods: Study I required 90 participants (u13: n = 40; u15: n = 50) to perform measures pertaining to anthropometric, morphological, flexibility and physical performance characteristics. This included stature, mass, body composition, limb length, flexibility, agility, and power measures. Study II was a case-control study (u15: n = 24), whereby the experimental group (n = 12) was exposed to a constraints-led batting protocol during the course of the cricket season. The objective of the protocol was to encourage the manipulation of the ball around the playing field. Pre- and post-intervention measures were performed using a batting skills test, which assessed batsmen’s capability to manipulate the ball to various areas of the playing field. Results: Study I revealed significant differences (p <0.0001) in stature, mass, limb length and power variables when comparing the u15 age group with the u13 age group. No differences were recorded for agility. The u13 age group had greater linear correlations for the variables of interest compared to the u15 age group. Study II revealed no differences in technical skill between the experimental group and the control (p <0.315).. The tests also revealed that adolescent batsmen favoured hitting deliveries through the extra-cover scoring zone. The third-man and fine-leg scoring zones were least preferred to hit deliveries through. A number of limitations to the study design resulted in the inability to determine the efficacy of a constraints-led batting protocol on skill development in an adolescent batting cohort. Conclusion: The results of study I indicated that the onset of puberty played an important role in the measures and performances between the u13 and u15 age groups. The results of study II indicated that adolescent batsmen are not adept at manipulating the ball around the field. Recommendations are provided for both studies.
- Full Text:
- Date Issued: 2016
An investigation into the interaction effects of simultaneous physical and cognitive task execution on performance, perceptual and physical responses
- Authors: Ross, Natalie
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3562 , vital:20525
- Description: Many modern day work environments require some degree of dual tasking, particularly the simultaneous performance of cognitive jobs alongside physical activity. The nature of such tasks is often job dependent and may require cognitive functions such as perception, decision making, memory, or response selection/execution in conjunction to task specific physical requirements. Previous research has indicated a possible relationship between concurrent physical and cognitive demands and task performance, safety and efficiency. However, this research is limited and inconsistent. The current study aimed to identify the interaction, if any, between concurrent physical and mental demands, and determine the impact of sensory modality and stage of information processing on this interaction, with specific focus on the performance, perceptual and physical responses during different types of cognitive tasks performed concurrently with a lifting task. 20 (10 male, 10 female) Rhodes University students participated in this study. Each participant performed 9 test conditions - a physical lifting task, a visual and an auditory memory task, and a visual and an auditory decision making task in isolation, as well as the lifting task concurrently with each of these cognitive tasks. Performance was recorded via accuracy and work output of cognitive tasks and the number of lifts for each condition. Perceptual measures were obtained via the Borg RPE and Subjective Workload Assessment Technique. Spinal kinematics were measured using the Lumbar Motion Monitor, while muscle activity of the Erector Spinae, Rectus Abdominis, Rectus Femoris and Biceps Femoris muscles were recorded using the Biometrix Data Logger surface EMG equipment. Mean results were analysed using a dependent T-test to observe any general interaction, and a Two-way ANOVA for the impact of sensory modality and stage of processing. Individual responses were also considered to gain better understanding of both intra and inter-human variability under the various test conditions. Results showed a significant decrease in cognitive performance, increased perception of physical effort, time pressure, mental effort and psychological stress under simultaneous physical and mental demands, while no significant differences in physical responses were observed. Further observations included increased dual-task interference during visual and decision-making tasks when combined with physical demands compared to that of auditory and memory tasks respectively. Individual responses showed large variability between individuals indicating the presence of positive, negative and non-responders to concurrent physical and mental demands. Results therefore imply an individual specific interaction between concurrent physical and mental demands that may or may not be detrimental to worker productivity, job error, injury rates and worker well-being, and that the type of cognitive task performed may impact this interaction.
- Full Text:
- Date Issued: 2016
- Authors: Ross, Natalie
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3562 , vital:20525
- Description: Many modern day work environments require some degree of dual tasking, particularly the simultaneous performance of cognitive jobs alongside physical activity. The nature of such tasks is often job dependent and may require cognitive functions such as perception, decision making, memory, or response selection/execution in conjunction to task specific physical requirements. Previous research has indicated a possible relationship between concurrent physical and cognitive demands and task performance, safety and efficiency. However, this research is limited and inconsistent. The current study aimed to identify the interaction, if any, between concurrent physical and mental demands, and determine the impact of sensory modality and stage of information processing on this interaction, with specific focus on the performance, perceptual and physical responses during different types of cognitive tasks performed concurrently with a lifting task. 20 (10 male, 10 female) Rhodes University students participated in this study. Each participant performed 9 test conditions - a physical lifting task, a visual and an auditory memory task, and a visual and an auditory decision making task in isolation, as well as the lifting task concurrently with each of these cognitive tasks. Performance was recorded via accuracy and work output of cognitive tasks and the number of lifts for each condition. Perceptual measures were obtained via the Borg RPE and Subjective Workload Assessment Technique. Spinal kinematics were measured using the Lumbar Motion Monitor, while muscle activity of the Erector Spinae, Rectus Abdominis, Rectus Femoris and Biceps Femoris muscles were recorded using the Biometrix Data Logger surface EMG equipment. Mean results were analysed using a dependent T-test to observe any general interaction, and a Two-way ANOVA for the impact of sensory modality and stage of processing. Individual responses were also considered to gain better understanding of both intra and inter-human variability under the various test conditions. Results showed a significant decrease in cognitive performance, increased perception of physical effort, time pressure, mental effort and psychological stress under simultaneous physical and mental demands, while no significant differences in physical responses were observed. Further observations included increased dual-task interference during visual and decision-making tasks when combined with physical demands compared to that of auditory and memory tasks respectively. Individual responses showed large variability between individuals indicating the presence of positive, negative and non-responders to concurrent physical and mental demands. Results therefore imply an individual specific interaction between concurrent physical and mental demands that may or may not be detrimental to worker productivity, job error, injury rates and worker well-being, and that the type of cognitive task performed may impact this interaction.
- Full Text:
- Date Issued: 2016
An investigation into the prevalence and growth of phishing attacks against South African financial targets
- Authors: Lala, Darshan Magan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3157 , vital:20379
- Description: Phishing in the electronic communications medium is the act of sending unsolicited email messages with the intention of masquerading as a reputed business. The objective is to deceive the recipient into divulging personal and sensitive information such as bank account details, credit card numbers and passwords. Attacks against financial services are the most common types of targets for scammers. Phishing attacks in South Africa have cost businesses and consumers substantial amounts of financial loss. This research investigated existing literature to understand the basic concepts of email, phishing, spam and how these fit together. The research also looks into the increasing growth of phishing worldwide and in particular against South African targets. A quantitative study is performed and reported on; this involves the study and analysis of phishing statistics in a data set provided by the South African Anti-Phishing Working Group. The data set contains phishing URL information, country code where the site has been hosted, targeted company name, IP address information and timestamp of the phishing site. The data set contains 161 different phishing targets. The research primarily focuses on the trend in phishing attacks against six South African based financial institutions, but also correlates this with the overall global trend using statistical analysis. The results from the study of the data set are compared to existing statistics and literature regarding the prevalence and growth of phishing in South Africa. The question that this research answers is whether or not the prevalence and growth of phishing in South Africa correlates with the global trend in phishing attacks. The findings indicate that certain correlations exist between some of the South African phishing targets and global phishing trends.
- Full Text:
- Date Issued: 2016
- Authors: Lala, Darshan Magan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3157 , vital:20379
- Description: Phishing in the electronic communications medium is the act of sending unsolicited email messages with the intention of masquerading as a reputed business. The objective is to deceive the recipient into divulging personal and sensitive information such as bank account details, credit card numbers and passwords. Attacks against financial services are the most common types of targets for scammers. Phishing attacks in South Africa have cost businesses and consumers substantial amounts of financial loss. This research investigated existing literature to understand the basic concepts of email, phishing, spam and how these fit together. The research also looks into the increasing growth of phishing worldwide and in particular against South African targets. A quantitative study is performed and reported on; this involves the study and analysis of phishing statistics in a data set provided by the South African Anti-Phishing Working Group. The data set contains phishing URL information, country code where the site has been hosted, targeted company name, IP address information and timestamp of the phishing site. The data set contains 161 different phishing targets. The research primarily focuses on the trend in phishing attacks against six South African based financial institutions, but also correlates this with the overall global trend using statistical analysis. The results from the study of the data set are compared to existing statistics and literature regarding the prevalence and growth of phishing in South Africa. The question that this research answers is whether or not the prevalence and growth of phishing in South Africa correlates with the global trend in phishing attacks. The findings indicate that certain correlations exist between some of the South African phishing targets and global phishing trends.
- Full Text:
- Date Issued: 2016
An investigation into the use of intuitive control interfaces and distributed processing for enhanced three dimensional sound localization
- Authors: Hedges, M L
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2992 , vital:20350
- Description: This thesis investigates the feasibility of using gestures as a means of control for localizing three dimesional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. The successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
- Full Text:
- Date Issued: 2016
- Authors: Hedges, M L
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2992 , vital:20350
- Description: This thesis investigates the feasibility of using gestures as a means of control for localizing three dimesional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. The successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
- Full Text:
- Date Issued: 2016
An investigation into the use of intuitive control interfaces and distributed processing for enhanced three dimensional sound localization
- Authors: Hedges, Mitchell Lawrence
- Date: 2016
- Subjects: Human-computer interaction , Acoustic localization , Sound -- Equipment and supplies , Acoustical engineering , Surround-sound systems , Wireless sensor nodes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4724 , http://hdl.handle.net/10962/d1020615
- Description: This thesis investigates the feasibility of using gestures as a means of control for localizing three dimensional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. the successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
- Full Text:
- Date Issued: 2016
- Authors: Hedges, Mitchell Lawrence
- Date: 2016
- Subjects: Human-computer interaction , Acoustic localization , Sound -- Equipment and supplies , Acoustical engineering , Surround-sound systems , Wireless sensor nodes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4724 , http://hdl.handle.net/10962/d1020615
- Description: This thesis investigates the feasibility of using gestures as a means of control for localizing three dimensional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. the successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
- Full Text:
- Date Issued: 2016