A cooperative benefits framework in South Africa's land redistribution process: the case of sugarcane farmland transfers
- Mbatha, Cyril N, Antrobus, Geoffrey G
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142922 , vital:38176 , DOI: 10.1080/03031853.2012.741207
- Description: A good indicator of successful land redistribution cases has to be the continuation of viable productivity rates in their post-transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately, negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to illustrate and argue that cooperation among key stakeholders, which could be enforced through long-term contracts between land buyers, sellers and new owners, may lead to maintenance and higher productivity levels and other benefits within the country's land redistribution process.
- Full Text:
- Date Issued: 2013
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142922 , vital:38176 , DOI: 10.1080/03031853.2012.741207
- Description: A good indicator of successful land redistribution cases has to be the continuation of viable productivity rates in their post-transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately, negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to illustrate and argue that cooperation among key stakeholders, which could be enforced through long-term contracts between land buyers, sellers and new owners, may lead to maintenance and higher productivity levels and other benefits within the country's land redistribution process.
- Full Text:
- Date Issued: 2013
A qualitative ecological risk assessment of the invasive Nile tilapia, Oreochromis niloticus in a sub-tropical African river system (Limpopo River, South Africa)
- Zengeya, Tsungai A, Robertson, Mark P, Booth, Anthony J, Chimimba, Christian T
- Authors: Zengeya, Tsungai A , Robertson, Mark P , Booth, Anthony J , Chimimba, Christian T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123575 , vital:35457 , https://doi.10.1002/aqc.2258
- Description: 1. This study outlines the development of a qualitative risk assessment method and its application as a screening tool for determining the risk of establishment and spread of the invasive Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), within the central sub-catchment of the Limpopo River basin in northern South Africa. 2. The assessment used known physiological tolerance limits of O. niloticus in relation to minimum water temperature, presence or absence of dams, seasonality of river flows, and the presence of indigenous fish species of concern to identify river systems that would be suitable for O. niloticus establishment. 3. River sections along the Limpopo main river channel and the immediate reaches of its associated tributaries east of the Limpopo/Lephalala river confluence along the Botswana–South Africa–Zimbabwe border were identified as being highly vulnerable to O. niloticus invasion. Rivers in the upper Bushveld catchment (Upper Limpopo, Mogalakwena, Lephalala, Mokolo, Matlabas and Crocodile rivers) were categorized as of medium ecological risk, while headwater streams were considered to be of low ecological risk. The decrease in vulnerability between lowveld and highveld river sections was mainly a function of low water temperatures (8–12˚C) associated with increasing altitude. 4. Oreochromis niloticus is already established in the lower catchment of the Limpopo River basin where indigenous congenerics are at an extinction risk through hybridization and competition exclusion. Oreochromis niloticus, therefore, poses an ecologically unacceptable risk to river systems in the upper catchment where it is yet to establish. The current risk assessment model provides a useful preliminary framework for the identification of river systems that are vulnerable to an O. niloticus invasion where conservation measures should be directed and implemented to prevent its introduction and spread within the Limpopo river system.
- Full Text:
- Date Issued: 2013
- Authors: Zengeya, Tsungai A , Robertson, Mark P , Booth, Anthony J , Chimimba, Christian T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123575 , vital:35457 , https://doi.10.1002/aqc.2258
- Description: 1. This study outlines the development of a qualitative risk assessment method and its application as a screening tool for determining the risk of establishment and spread of the invasive Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), within the central sub-catchment of the Limpopo River basin in northern South Africa. 2. The assessment used known physiological tolerance limits of O. niloticus in relation to minimum water temperature, presence or absence of dams, seasonality of river flows, and the presence of indigenous fish species of concern to identify river systems that would be suitable for O. niloticus establishment. 3. River sections along the Limpopo main river channel and the immediate reaches of its associated tributaries east of the Limpopo/Lephalala river confluence along the Botswana–South Africa–Zimbabwe border were identified as being highly vulnerable to O. niloticus invasion. Rivers in the upper Bushveld catchment (Upper Limpopo, Mogalakwena, Lephalala, Mokolo, Matlabas and Crocodile rivers) were categorized as of medium ecological risk, while headwater streams were considered to be of low ecological risk. The decrease in vulnerability between lowveld and highveld river sections was mainly a function of low water temperatures (8–12˚C) associated with increasing altitude. 4. Oreochromis niloticus is already established in the lower catchment of the Limpopo River basin where indigenous congenerics are at an extinction risk through hybridization and competition exclusion. Oreochromis niloticus, therefore, poses an ecologically unacceptable risk to river systems in the upper catchment where it is yet to establish. The current risk assessment model provides a useful preliminary framework for the identification of river systems that are vulnerable to an O. niloticus invasion where conservation measures should be directed and implemented to prevent its introduction and spread within the Limpopo river system.
- Full Text:
- Date Issued: 2013
An invader within an altered landscape: one catfish, two rivers and an inter-basin water transfer scheme
- Kadye, Wilbert T, Booth, Anthony J
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123776 , vital:35494 , https://doi.10.1002/rra.2599
- Description: African sharptooth catfish Clarias gariepinus has become established as a non-native invasive species in Eastern Cape, South Africa, where it was translocated primarily through an inter-basin water transfer scheme into the Great Fish and Sundays rivers. This study examined the patterns in catfish distribution and abundance, and compared trophic niches in relation to the ichthyofauna of the two rivers. Correspondence analysis revealed upstream to downstream gradients associated with the spatial distribution in species richness for most species within the mainstream and mainstream to tributary gradients that were associated mostly with the spatial distribution of native minnows in both rivers. Catfish was predicted to occur widely within the mainstream habitats and to decrease progressively from mainstreams to tributaries. Based on classification and regression trees, the physico-chemical environment was found to be a good proxy for predicting the occurrence and abundance of catfish. Although non-significant relationships were observed between catfish and other native fish species abundances, the study suggests potential impact due to predation and interference in habitats where the invader co-occurs with other fishes. Comparisons of trophic niches indicated higher trophic diversity for the mainstream ichthyofauna than the tributary communities in both rivers, suggesting an upstream to downstream continuum in community structure and resource availability. Catfish within the invaded mainstream had comparable trophic niches and similar dispersion patterns among individuals for both rivers, but indicated differences in shapes of scatter. This suggests that the catfish exhibited a differential response, probably in relation to resource availability, that may be indicative of its dietary plasticity. The study suggests the proliferation of catfish and its probable impact within the mainstream flow-altered habitats where invasion resistance was possibly reduced. Comparisons of trophic niches provided information on its probable impact at different scales and the potential risk of invasion of tributaries inhabited by native minnow species.
- Full Text:
- Date Issued: 2013
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123776 , vital:35494 , https://doi.10.1002/rra.2599
- Description: African sharptooth catfish Clarias gariepinus has become established as a non-native invasive species in Eastern Cape, South Africa, where it was translocated primarily through an inter-basin water transfer scheme into the Great Fish and Sundays rivers. This study examined the patterns in catfish distribution and abundance, and compared trophic niches in relation to the ichthyofauna of the two rivers. Correspondence analysis revealed upstream to downstream gradients associated with the spatial distribution in species richness for most species within the mainstream and mainstream to tributary gradients that were associated mostly with the spatial distribution of native minnows in both rivers. Catfish was predicted to occur widely within the mainstream habitats and to decrease progressively from mainstreams to tributaries. Based on classification and regression trees, the physico-chemical environment was found to be a good proxy for predicting the occurrence and abundance of catfish. Although non-significant relationships were observed between catfish and other native fish species abundances, the study suggests potential impact due to predation and interference in habitats where the invader co-occurs with other fishes. Comparisons of trophic niches indicated higher trophic diversity for the mainstream ichthyofauna than the tributary communities in both rivers, suggesting an upstream to downstream continuum in community structure and resource availability. Catfish within the invaded mainstream had comparable trophic niches and similar dispersion patterns among individuals for both rivers, but indicated differences in shapes of scatter. This suggests that the catfish exhibited a differential response, probably in relation to resource availability, that may be indicative of its dietary plasticity. The study suggests the proliferation of catfish and its probable impact within the mainstream flow-altered habitats where invasion resistance was possibly reduced. Comparisons of trophic niches provided information on its probable impact at different scales and the potential risk of invasion of tributaries inhabited by native minnow species.
- Full Text:
- Date Issued: 2013
Controls on the formation of Wakkerstroom Vlei, Mpumalanga province, South Africa:
- Joubert, R, Ellery, William F N
- Authors: Joubert, R , Ellery, William F N
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144421 , vital:38344 , DOI: 10.2989/16085914.2012.762897
- Description: The present study investigated controls on the formation of Wakkerstroom Vlei, an 1 000 ha unchannelled valley-bottom wetland on the South African Highveld. Along the uppermost and lowermost reaches of the wetland, where dolerite outcrops occur along the main valley, hydrogeomorphic features typical of geological control on wetland formation are present, including a meandering river channel, oxbow lakes and greater than 3 m deep organic-poor alluvial fill. Along the main body of the wetland, however, floodplain features are absent, alluvial fill is up to 4.5 m deep and contains up to 2 m deep accumulations of peat. These characteristics deviate from the traditional model of dolerite control on wetland formation described by several other studies on Highveld wetland systems.
- Full Text:
- Date Issued: 2013
- Authors: Joubert, R , Ellery, William F N
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144421 , vital:38344 , DOI: 10.2989/16085914.2012.762897
- Description: The present study investigated controls on the formation of Wakkerstroom Vlei, an 1 000 ha unchannelled valley-bottom wetland on the South African Highveld. Along the uppermost and lowermost reaches of the wetland, where dolerite outcrops occur along the main valley, hydrogeomorphic features typical of geological control on wetland formation are present, including a meandering river channel, oxbow lakes and greater than 3 m deep organic-poor alluvial fill. Along the main body of the wetland, however, floodplain features are absent, alluvial fill is up to 4.5 m deep and contains up to 2 m deep accumulations of peat. These characteristics deviate from the traditional model of dolerite control on wetland formation described by several other studies on Highveld wetland systems.
- Full Text:
- Date Issued: 2013
Ecological niche modeling of the invasive potential of Nile tilapia Oreochromis niloticus in African river systems: concerns and implications for the conservation of indigenous congenerics
- Zengeya, Tsungai A, Robertson, Mark P, Booth, Anthony J, Chimimba, Christian T
- Authors: Zengeya, Tsungai A , Robertson, Mark P , Booth, Anthony J , Chimimba, Christian T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124341 , vital:35596 , https://doi.10.1007/s10530-012-0386-7
- Description: This study applied ecological niche models to determine the potential invasive range of Nile tilapia, Oreochromis niloticus, with a particular focus on river systems in southern Africa where it is now established and spreading. Computational tools such as niche models are useful in predicting the potential range of invasive species, but there are limitations to their application. In particular, models trained on native records may fail to predict the full extent of an invasion. This failure is often attributed to changes in either the niche of the invading species or the variables used to develop the models. In this study, we therefore evaluated the differences in the predictive power of models trained with different environmental variables, the effect of species range (native vs. introduced) on model performance and assessed whether or not there is evidence suggestive of a niche shift in Nile tilapia following its introduction. Niche models were constructed using Maxent and the degree of niche similarity was assessed using Schoener‘s index. Null models were used to test for significance. Model performance and niche conservatism varied significantly with variable selection and species range. This indicates that the environmental conditions available to Nile tilapia in its native and introduced ranges are not congruent. Nile tilapia exhibited broad invasive potential over most of southern Africa that overlaps the natural range of endemic congenerics. Of particular concern are areas which are free of exotic species but are now vulnerable due to the promotion of fish introductions mainly for aquaculture and sport fishing.
- Full Text:
- Date Issued: 2013
- Authors: Zengeya, Tsungai A , Robertson, Mark P , Booth, Anthony J , Chimimba, Christian T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124341 , vital:35596 , https://doi.10.1007/s10530-012-0386-7
- Description: This study applied ecological niche models to determine the potential invasive range of Nile tilapia, Oreochromis niloticus, with a particular focus on river systems in southern Africa where it is now established and spreading. Computational tools such as niche models are useful in predicting the potential range of invasive species, but there are limitations to their application. In particular, models trained on native records may fail to predict the full extent of an invasion. This failure is often attributed to changes in either the niche of the invading species or the variables used to develop the models. In this study, we therefore evaluated the differences in the predictive power of models trained with different environmental variables, the effect of species range (native vs. introduced) on model performance and assessed whether or not there is evidence suggestive of a niche shift in Nile tilapia following its introduction. Niche models were constructed using Maxent and the degree of niche similarity was assessed using Schoener‘s index. Null models were used to test for significance. Model performance and niche conservatism varied significantly with variable selection and species range. This indicates that the environmental conditions available to Nile tilapia in its native and introduced ranges are not congruent. Nile tilapia exhibited broad invasive potential over most of southern Africa that overlaps the natural range of endemic congenerics. Of particular concern are areas which are free of exotic species but are now vulnerable due to the promotion of fish introductions mainly for aquaculture and sport fishing.
- Full Text:
- Date Issued: 2013
Inkcubeko Nendalo: a bio-cultural diversity schools education project in South Africa and its implications for inclusive Indigenous Knowledge Systems (IKS) Sustainability.
- Cocks, Michelle L, Alexander, Jamie K, Dold, Anthony P
- Authors: Cocks, Michelle L , Alexander, Jamie K , Dold, Anthony P
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141187 , vital:37951 , DOI: 10.1177/0973408212475232
- Description: South Africa is currently the world’s third most biodiverse country, with one of the highest concentrations of threatened biodiversity in the world. Emerging research reveals the increasing pressure on this biodiversity with many wild resources continuing to be utilised for livelihood purposes even within urban environments. The Rio conventions, particularly the CBD, call for an integrated approach to conservation that incorporates local environmental knowledge and practices. In a bid to market itself as globally competitive, South Africa’s Curriculum 2005 (C 2005) is primarily focused on Western-based scientific knowledge, which sidelines the contribution of indigenous knowledge systems (IKS) and ignores the holistic nature of indigenous worldviews. The Inkcubeko Nendalo programme is designed to revitalise cultural identity, showing children the value of local indigenous knowledge and cultural environmental values.
- Full Text:
- Date Issued: 2013
- Authors: Cocks, Michelle L , Alexander, Jamie K , Dold, Anthony P
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141187 , vital:37951 , DOI: 10.1177/0973408212475232
- Description: South Africa is currently the world’s third most biodiverse country, with one of the highest concentrations of threatened biodiversity in the world. Emerging research reveals the increasing pressure on this biodiversity with many wild resources continuing to be utilised for livelihood purposes even within urban environments. The Rio conventions, particularly the CBD, call for an integrated approach to conservation that incorporates local environmental knowledge and practices. In a bid to market itself as globally competitive, South Africa’s Curriculum 2005 (C 2005) is primarily focused on Western-based scientific knowledge, which sidelines the contribution of indigenous knowledge systems (IKS) and ignores the holistic nature of indigenous worldviews. The Inkcubeko Nendalo programme is designed to revitalise cultural identity, showing children the value of local indigenous knowledge and cultural environmental values.
- Full Text:
- Date Issued: 2013
Movement patterns and habitat selection of invasive African sharptooth catfish
- Kadye, Wilbert T, Booth, Anthony J
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125276 , vital:35767 , http://dx.doi.10.1111/j.1469-7998.2012.00960.x
- Description: Information on the movement behaviour and habitat use by non-native invasive African catfish Clarias gariepinus is crucial in understanding and possibly mitigating its potential impacts. The aim of this study was to examine catfish movement and habitat selection within an invaded impoundment in the Eastern Cape, South Africa. Acoustic telemetry data for 10 tagged catfish were analyzed to identify spatial patterns in home ranges and seasonal changes in habitat associations. Long-distance movements were observed for most catfish from common central release point, whereas short-distance movements defined their home ranges and utilization distributions that were categorized as localized within single or multiple habitats. Habitat selection was non-random with most catfish utilizing the shallow river mouth and upper section of the reservoir that were dominated by a rocky substratum interspersed with submerged trees. These localities were likely to be preferred for spawning and/or feeding. Utilization of these habitats by catfish is likely to be associated with probable impact due to predation and interference competition for feeding and breeding grounds with other species. Although most catfish maintained their home ranges throughout the study, seasonal shifts in habitat use, which was reflected by the utilization of deep and silt-dominated habitats, were also observed for some catfish. Non-random habitat use and homing behaviour within single and multiple habitats by non-native sharptooth catfish suggests that its impact within the invaded habitats may be associated with particular habitats both at broad spatial and temporal scales. Protection of habitats from catfish invasion should be considered as a management option to conserve native biota.
- Full Text:
- Date Issued: 2013
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125276 , vital:35767 , http://dx.doi.10.1111/j.1469-7998.2012.00960.x
- Description: Information on the movement behaviour and habitat use by non-native invasive African catfish Clarias gariepinus is crucial in understanding and possibly mitigating its potential impacts. The aim of this study was to examine catfish movement and habitat selection within an invaded impoundment in the Eastern Cape, South Africa. Acoustic telemetry data for 10 tagged catfish were analyzed to identify spatial patterns in home ranges and seasonal changes in habitat associations. Long-distance movements were observed for most catfish from common central release point, whereas short-distance movements defined their home ranges and utilization distributions that were categorized as localized within single or multiple habitats. Habitat selection was non-random with most catfish utilizing the shallow river mouth and upper section of the reservoir that were dominated by a rocky substratum interspersed with submerged trees. These localities were likely to be preferred for spawning and/or feeding. Utilization of these habitats by catfish is likely to be associated with probable impact due to predation and interference competition for feeding and breeding grounds with other species. Although most catfish maintained their home ranges throughout the study, seasonal shifts in habitat use, which was reflected by the utilization of deep and silt-dominated habitats, were also observed for some catfish. Non-random habitat use and homing behaviour within single and multiple habitats by non-native sharptooth catfish suggests that its impact within the invaded habitats may be associated with particular habitats both at broad spatial and temporal scales. Protection of habitats from catfish invasion should be considered as a management option to conserve native biota.
- Full Text:
- Date Issued: 2013
TeleWeaver: an innovative telecommunication platform for marginalized communities in Africa
- Dalvit, Lorenzo, Gumbo, Sibukelo, Ntshinga, Lindikaya, Terzoli, Alfredo, Hansen, Susan
- Authors: Dalvit, Lorenzo , Gumbo, Sibukelo , Ntshinga, Lindikaya , Terzoli, Alfredo , Hansen, Susan
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431317 , vital:72763 , https://www.academic-bookshop.com/ourshop/prod_2659103-ECEG-2013-13th-European-Conference-on-eGovernment-Como-Italy-PRINT-version.html
- Description: Information and Communication Technologies for Development (ICT4D) is becoming an increasingly important and multi‐faceted area of research and software development. Particularly through provision via mobile devices, e‐services can potentially reach and improve the lives of millions of people living in marginalised areas. The efforts of many governments in sub‐Saharan Africa are frustrated by poor tele-communication infrastructure, lack of skills and unsustainable models of intervention. In this paper we describe the holistic solution offered by the TeleWeaver platform. The novel approach to the development of the software, the strong sense of social responsibility of the developers and the collaborative spirit that shaped the ecosystem of which Tele-Weaver is part, warrants the adoption of an innovative approach to its marketing and implementation. On the one hand, the project needs to provide returns on investment and generate profit for the key stake-holders (ie government at the local and national level, academia, indus-try and socio‐-entrepreneurs in the target community). On the other, it must benefit all members of the marginalised communities it is intended to serve as well as the global community of software developers. Tele-Weaver was developed in close collaboration with the community of Dwesa, a rural area on the Wild Cost of the Transkei regions in eastern South Africa.
- Full Text:
- Date Issued: 2013
- Authors: Dalvit, Lorenzo , Gumbo, Sibukelo , Ntshinga, Lindikaya , Terzoli, Alfredo , Hansen, Susan
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431317 , vital:72763 , https://www.academic-bookshop.com/ourshop/prod_2659103-ECEG-2013-13th-European-Conference-on-eGovernment-Como-Italy-PRINT-version.html
- Description: Information and Communication Technologies for Development (ICT4D) is becoming an increasingly important and multi‐faceted area of research and software development. Particularly through provision via mobile devices, e‐services can potentially reach and improve the lives of millions of people living in marginalised areas. The efforts of many governments in sub‐Saharan Africa are frustrated by poor tele-communication infrastructure, lack of skills and unsustainable models of intervention. In this paper we describe the holistic solution offered by the TeleWeaver platform. The novel approach to the development of the software, the strong sense of social responsibility of the developers and the collaborative spirit that shaped the ecosystem of which Tele-Weaver is part, warrants the adoption of an innovative approach to its marketing and implementation. On the one hand, the project needs to provide returns on investment and generate profit for the key stake-holders (ie government at the local and national level, academia, indus-try and socio‐-entrepreneurs in the target community). On the other, it must benefit all members of the marginalised communities it is intended to serve as well as the global community of software developers. Tele-Weaver was developed in close collaboration with the community of Dwesa, a rural area on the Wild Cost of the Transkei regions in eastern South Africa.
- Full Text:
- Date Issued: 2013
The AES64 Connection Management and Control Protocol
- Foss, Richard, Gurdan, Robby, Klinkradt, Bradley, Chigwamba, Nyasha
- Authors: Foss, Richard , Gurdan, Robby , Klinkradt, Bradley , Chigwamba, Nyasha
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426933 , vital:72402 , https://www.aes.org/e-lib/browse.cfm?elib=16705
- Description: AES64, which is an IP-based peer-to-peer network control protocol, integrates the connection management and control capabilities across digital audio networks. This enables the streaming of all types of media content among devices from different manufactures because it provides a common approach for device control. This paper describes this protocol. Each parameter of a device can be addressed with a 7-level hierarchical structure that reflects the functional layout of the device. The protocol has been implemented in many different types of networks.
- Full Text:
- Date Issued: 2013
- Authors: Foss, Richard , Gurdan, Robby , Klinkradt, Bradley , Chigwamba, Nyasha
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426933 , vital:72402 , https://www.aes.org/e-lib/browse.cfm?elib=16705
- Description: AES64, which is an IP-based peer-to-peer network control protocol, integrates the connection management and control capabilities across digital audio networks. This enables the streaming of all types of media content among devices from different manufactures because it provides a common approach for device control. This paper describes this protocol. Each parameter of a device can be addressed with a 7-level hierarchical structure that reflects the functional layout of the device. The protocol has been implemented in many different types of networks.
- Full Text:
- Date Issued: 2013
An Analysis and Implementation of Methods for High Speed Lexical Classification of Malicious URLs
- Egan, Shaun P, Irwin, Barry V W
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429757 , vital:72637 , https://digifors.cs.up.ac.za/issa/2012/Proceedings/Research/58_ResearchInProgress.pdf
- Description: Several authors have put forward methods of using Artificial Neural Networks (ANN) to classify URLs as malicious or benign by using lexical features of those URLs. These methods have been compared to other methods of classification, such as blacklisting and spam filtering, and have been found to be as accurate. Early attempts proved to be as highly accurate. Fully featured classifications use lexical features as well as lookups to classify URLs and include (but are not limited to) blacklists, spam filters and reputation services. These classifiers are based on the Online Perceptron Model, using a single neuron as a linear combiner and used lexical features that rely on the presence (or lack thereof) of words belonging to a bag-of-words. Several obfuscation resistant features are also used to increase the positive classification rate of these perceptrons. Examples of these include URL length, number of directory traversals and length of arguments passed to the file within the URL. In this paper we describe how we implement the online perceptron model and methods that we used to try to increase the accuracy of this model through the use of hidden layers and training cost validation. We discuss our results in relation to those of other papers, as well as other analysis performed on the training data and the neural networks themselves to best understand why they are so effective. Also described will be the proposed model for developing these Neural Networks, how to implement them in the real world through the use of browser extensions, proxy plugins and spam filters for mail servers, and our current implementation. Finally, work that is still in progress will be described. This work includes other methods of increasing accuracy through the use of modern training techniques and testing in a real world environment.
- Full Text:
- Date Issued: 2012
- Authors: Egan, Shaun P , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429757 , vital:72637 , https://digifors.cs.up.ac.za/issa/2012/Proceedings/Research/58_ResearchInProgress.pdf
- Description: Several authors have put forward methods of using Artificial Neural Networks (ANN) to classify URLs as malicious or benign by using lexical features of those URLs. These methods have been compared to other methods of classification, such as blacklisting and spam filtering, and have been found to be as accurate. Early attempts proved to be as highly accurate. Fully featured classifications use lexical features as well as lookups to classify URLs and include (but are not limited to) blacklists, spam filters and reputation services. These classifiers are based on the Online Perceptron Model, using a single neuron as a linear combiner and used lexical features that rely on the presence (or lack thereof) of words belonging to a bag-of-words. Several obfuscation resistant features are also used to increase the positive classification rate of these perceptrons. Examples of these include URL length, number of directory traversals and length of arguments passed to the file within the URL. In this paper we describe how we implement the online perceptron model and methods that we used to try to increase the accuracy of this model through the use of hidden layers and training cost validation. We discuss our results in relation to those of other papers, as well as other analysis performed on the training data and the neural networks themselves to best understand why they are so effective. Also described will be the proposed model for developing these Neural Networks, how to implement them in the real world through the use of browser extensions, proxy plugins and spam filters for mail servers, and our current implementation. Finally, work that is still in progress will be described. This work includes other methods of increasing accuracy through the use of modern training techniques and testing in a real world environment.
- Full Text:
- Date Issued: 2012
Building a Graphical Fuzzing Framework
- Zeisberger, Sascha, Irwin, Barry V W
- Authors: Zeisberger, Sascha , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429772 , vital:72638 , https://digifors.cs.up.ac.za/issa/2012/Proceedings/Research/59_ResearchInProgress.pdf
- Description: Fuzz testing is a robustness testing technique that sends malformed data to an application’s input. This is to test an application’s behaviour when presented with input beyond its specification. The main difference between traditional testing techniques and fuzz testing is that in most traditional techniques an application is tested according to a specification and rated on how well the application conforms to that specification. Fuzz testing tests beyond the scope of a specification by intelligently generating values that may be interpreted by an application in an unintended manner. The use of fuzz testing has been more prevalent in academic and security communities despite showing success in production environments. To measure the effectiveness of fuzz testing, an experiment was conducted where several publicly available applications were fuzzed. In some instances, fuzz testing was able to force an application into an invalid state and it was concluded that fuzz testing is a relevant testing technique that could assist in developing more robust applications. This success prompted a further investigation into fuzz testing in order to compile a list of requirements that makes an effective fuzzer. The aforementioned investigation assisted in the design of a fuzz testing framework, the goal of which is to make the process more accessible to users outside of an academic and security environment. Design methodologies and justifications of said framework are discussed, focusing on the graphical user interface components as this aspect of the framework is used to increase the usability of the framework.
- Full Text:
- Date Issued: 2012
- Authors: Zeisberger, Sascha , Irwin, Barry V W
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429772 , vital:72638 , https://digifors.cs.up.ac.za/issa/2012/Proceedings/Research/59_ResearchInProgress.pdf
- Description: Fuzz testing is a robustness testing technique that sends malformed data to an application’s input. This is to test an application’s behaviour when presented with input beyond its specification. The main difference between traditional testing techniques and fuzz testing is that in most traditional techniques an application is tested according to a specification and rated on how well the application conforms to that specification. Fuzz testing tests beyond the scope of a specification by intelligently generating values that may be interpreted by an application in an unintended manner. The use of fuzz testing has been more prevalent in academic and security communities despite showing success in production environments. To measure the effectiveness of fuzz testing, an experiment was conducted where several publicly available applications were fuzzed. In some instances, fuzz testing was able to force an application into an invalid state and it was concluded that fuzz testing is a relevant testing technique that could assist in developing more robust applications. This success prompted a further investigation into fuzz testing in order to compile a list of requirements that makes an effective fuzzer. The aforementioned investigation assisted in the design of a fuzz testing framework, the goal of which is to make the process more accessible to users outside of an academic and security environment. Design methodologies and justifications of said framework are discussed, focusing on the graphical user interface components as this aspect of the framework is used to increase the usability of the framework.
- Full Text:
- Date Issued: 2012
Design of realistic hybrid marine resource management programs in Oceania
- Aswani, Shankar, Ruddle, Kenneth
- Authors: Aswani, Shankar , Ruddle, Kenneth
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70615 , vital:29681 , https://doi.org/10.2984/67.3.11
- Description: This review article synthesizes the authors' several decades of multidisciplinary natural and social science and applied marine resource management experience in the Asia-Pacific region to examine the strengthening of coastal and marine resource management and conservation using alliances between local communities and external institutions. The objective is to assist the design of resource management and conservation programs that enhance the capacity of coastal communities in Oceania to confront both diminishing marine resources and the effects of climate change by providing guidelines for protecting marine biodiversity and vulnerable ecosystem functions. This article describes a management framework that hybridizes local beliefs and institutions expressed in customary management (CM) with such modern management concepts as marine protected areas (MPAs) and ecosystem-based management (EBM). Hybrid management accommodates the social, political, economic, and cultural contexts of Oceanic communities and, compared with recent or conventional management approaches, can therefore better address fundamental local concerns such as coastal degradation, climate change, sea level rise, weak governance, corruption, limited resources and staff to manage and monitor marine resources, and increasing poverty. Research on the hybridization of management systems demonstrates opportunities to establish context-appropriate EBM and/or other managerial arrangements that include terrestrial and adjacent coastal-marine ecosystems. Formal and informal CM systems are widespread in Oceania and in some parts of Southeast Asia, and if appropriate strategies are employed rapid progress toward hybrid CM-EBM could be enabled.
- Full Text:
- Date Issued: 2012
- Authors: Aswani, Shankar , Ruddle, Kenneth
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70615 , vital:29681 , https://doi.org/10.2984/67.3.11
- Description: This review article synthesizes the authors' several decades of multidisciplinary natural and social science and applied marine resource management experience in the Asia-Pacific region to examine the strengthening of coastal and marine resource management and conservation using alliances between local communities and external institutions. The objective is to assist the design of resource management and conservation programs that enhance the capacity of coastal communities in Oceania to confront both diminishing marine resources and the effects of climate change by providing guidelines for protecting marine biodiversity and vulnerable ecosystem functions. This article describes a management framework that hybridizes local beliefs and institutions expressed in customary management (CM) with such modern management concepts as marine protected areas (MPAs) and ecosystem-based management (EBM). Hybrid management accommodates the social, political, economic, and cultural contexts of Oceanic communities and, compared with recent or conventional management approaches, can therefore better address fundamental local concerns such as coastal degradation, climate change, sea level rise, weak governance, corruption, limited resources and staff to manage and monitor marine resources, and increasing poverty. Research on the hybridization of management systems demonstrates opportunities to establish context-appropriate EBM and/or other managerial arrangements that include terrestrial and adjacent coastal-marine ecosystems. Formal and informal CM systems are widespread in Oceania and in some parts of Southeast Asia, and if appropriate strategies are employed rapid progress toward hybrid CM-EBM could be enabled.
- Full Text:
- Date Issued: 2012
Life-history characteristics of an age-validated established invasive African sharptooth catfish, Clarias gariepinus, population in a warm–temperate African impoundment
- Wartenberg, Reece, Weyl, Olaf L F, Booth, Anthony J, Winker, A Henning
- Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124921 , vital:35710 , https://doi.10.3377/004.048.0225
- Description: African sharptooth catfish Clarias gariepinus (Burchell, 1822) is a widely distributed fish that has now invaded water bodies in South America, Eastern Europe, Asia and South Africa (Cambray 2003). In South Africa it is native as far south as the Orange-Vaal river system, but inter-basin water transfer schemes (IBWTs), illegal stocking by anglers and from aquaculture has resulted in the establishment of extralimital populations in almost all river systems (van Rensburg et al. 2011). Within the Eastern Cape Province, C. gariepinus has invaded the Great Fish and Sundays rivers through IBWTs, that connect the Orange River to the Great Fish River and then to the Sundays River system which flows directly into Darlington Dam (Kadye & Booth 2013a) (Fig. 1). Soon after the completion of the IBWTs sharptooth catfish were recorded in Grassridge Dam in 1976 (Laurenson & Hocutt 1985), and later from Darlington Dam in 1981 (Scott et al. 2006). Although Cambray & Jubb (1977) are of the opinion that the species was translocated prior to the IBWT connection, there is now a permanent corridor between the Orange River and its receiving river systems that can facilitate the continued introduction of non-native Orange River fishes and other aquatic biota.
- Full Text:
- Date Issued: 2012
- Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124921 , vital:35710 , https://doi.10.3377/004.048.0225
- Description: African sharptooth catfish Clarias gariepinus (Burchell, 1822) is a widely distributed fish that has now invaded water bodies in South America, Eastern Europe, Asia and South Africa (Cambray 2003). In South Africa it is native as far south as the Orange-Vaal river system, but inter-basin water transfer schemes (IBWTs), illegal stocking by anglers and from aquaculture has resulted in the establishment of extralimital populations in almost all river systems (van Rensburg et al. 2011). Within the Eastern Cape Province, C. gariepinus has invaded the Great Fish and Sundays rivers through IBWTs, that connect the Orange River to the Great Fish River and then to the Sundays River system which flows directly into Darlington Dam (Kadye & Booth 2013a) (Fig. 1). Soon after the completion of the IBWTs sharptooth catfish were recorded in Grassridge Dam in 1976 (Laurenson & Hocutt 1985), and later from Darlington Dam in 1981 (Scott et al. 2006). Although Cambray & Jubb (1977) are of the opinion that the species was translocated prior to the IBWT connection, there is now a permanent corridor between the Orange River and its receiving river systems that can facilitate the continued introduction of non-native Orange River fishes and other aquatic biota.
- Full Text:
- Date Issued: 2012
Where angels fear to tread: online peer-assessment in a large first-year class
- Mostert, Markus, Snowball, Jeanette D
- Authors: Mostert, Markus , Snowball, Jeanette D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69289 , vital:29480 , https://doi.org/10.1080/02602938.2012.683770
- Description: In the context of widening participation, large classes and increased diversity, assessment of student learning is becoming increasingly problematic in that providing formative feedback aimed at developing student writing proves to be particularly laborious. Although the potential value of peer assessment has been well documented in the literature, the associated administrative burden, also in relation to managing anonymity and intellectual ownership, makes this option less attractive, particularly in large classes. A potential solution involves the use of information and communication technologies to automate the logistics associated with peer assessment in a time-efficient way. However, uptake of such systems in the higher education community is limited, and research in this area is only beginning. This case study reports on the use of the Moodle Workshop module for formative peer assessment of students’ individual work in a first-year introductory macro-economics class of over 800 students. Data were collected through an end-of-course evaluation survey of students. The study found that using the feature-rich Workshop module not only addressed many of the practical challenges associated with paper-based peer assessments, but also provided a range of additional options for enhancing validity and reliability of peer assessments that would not be possible with paper-based systems.
- Full Text: false
- Date Issued: 2012
- Authors: Mostert, Markus , Snowball, Jeanette D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69289 , vital:29480 , https://doi.org/10.1080/02602938.2012.683770
- Description: In the context of widening participation, large classes and increased diversity, assessment of student learning is becoming increasingly problematic in that providing formative feedback aimed at developing student writing proves to be particularly laborious. Although the potential value of peer assessment has been well documented in the literature, the associated administrative burden, also in relation to managing anonymity and intellectual ownership, makes this option less attractive, particularly in large classes. A potential solution involves the use of information and communication technologies to automate the logistics associated with peer assessment in a time-efficient way. However, uptake of such systems in the higher education community is limited, and research in this area is only beginning. This case study reports on the use of the Moodle Workshop module for formative peer assessment of students’ individual work in a first-year introductory macro-economics class of over 800 students. Data were collected through an end-of-course evaluation survey of students. The study found that using the feature-rich Workshop module not only addressed many of the practical challenges associated with paper-based peer assessments, but also provided a range of additional options for enhancing validity and reliability of peer assessments that would not be possible with paper-based systems.
- Full Text: false
- Date Issued: 2012
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