A knowledge-oriented, context-sensitive architectural framework for service deployment in marginalized rural communities
- Authors: Thinyane, Mamello P
- Date: 2009
- Subjects: Information technology Expert systems (Computer science) Software architecture User interfaces (Computer systems) Ethnoscience Social networks Rural development Technical assistance -- Developing countries Information networks -- Developing countries
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4599 , http://hdl.handle.net/10962/d1004843
- Description: The notion of a global knowledge society is somewhat of a misnomer due to the fact that large portions of the global community are not participants in this global knowledge society which is driven, shaped by and socio-technically biased towards a small fraction of the global population. Information and Communication Technology (ICT) is culture-sensitive and this is a dynamic that is largely ignored in the majority of ICT for Development (ICT4D) interventions, leading to the technological determinism flaw and ultimately a failure of the undertaken projects. The deployment of ICT solutions, in particular in the context of ICT4D, must be informed by the cultural and socio-technical profile of the deployment environments and solutions themselves must be developed with a focus towards context-sensitivity and ethnocentricity. In this thesis, we investigate the viability of a software architectural framework for the development of ICT solutions that are context-sensitive and ethnocentric1, and so aligned with the cultural and social dynamics within the environment of deployment. The conceptual framework, named PIASK, defines five tiers (presentation, interaction, access, social networking, and knowledge base) which allow for: behavioural completeness of the layer components; a modular and functionally decoupled architecture; and the flexibility to situate and contextualize the developed applications along the dimensions of the User Interface (UI), interaction modalities, usage metaphors, underlying Indigenous Knowledge (IK), and access protocols. We have developed a proof-of-concept service platform, called KnowNet, based on the PIASK architecture. KnowNet is built around the knowledge base layer, which consists of domain ontologies that encapsulate the knowledge in the platform, with an intrinsic flexibility to access secondary knowledge repositories. The domain ontologies constructed (as examples) are for the provisioning of eServices to support societal activities (e.g. commerce, health, agriculture, medicine) within a rural and marginalized area of Dwesa, in the Eastern Cape province of South Africa. The social networking layer allows for situating the platform within the local social systems. Heterogeneity of user profiles and multiplicity of end-user devices are handled through the access and the presentation components, and the service logic is implemented by the interaction components. This services platform validates the PIASK architecture for end-to-end provisioning of multi-modal, heterogeneous, ontology-based services. The development of KnowNet was informed on one hand by the latest trends within service architectures, semantic web technologies and social applications, and on the other hand by the context consideration based on the profile (IK systems dynamics, infrastructure, usability requirements) of the Dwesa community. The realization of the service platform is based on the JADE Multi-Agent System (MAS), and this shows the applicability and adequacy of MAS’s for service deployment in a rural context, at the same time providing key advantages such as platform fault-tolerance, robustness and flexibility. While the context of conceptualization of PIASK and the implementation of KnowNet is that of rurality and of ICT4D, the applicability of the architecture extends to other similarly heterogeneous and context-sensitive domains. KnowNet has been validated for functional and technical adequacy, and we have also undertaken an initial prevalidation for social context sensitivity. We observe that the five tier PIASK architecture provides an adequate framework for developing context-sensitive and ethnocentric software: by functionally separating and making explicit the social networking and access tier components, while still maintaining the traditional separation of presentation, business logic and data components.
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- Authors: Thinyane, Mamello P
- Date: 2009
- Subjects: Information technology Expert systems (Computer science) Software architecture User interfaces (Computer systems) Ethnoscience Social networks Rural development Technical assistance -- Developing countries Information networks -- Developing countries
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4599 , http://hdl.handle.net/10962/d1004843
- Description: The notion of a global knowledge society is somewhat of a misnomer due to the fact that large portions of the global community are not participants in this global knowledge society which is driven, shaped by and socio-technically biased towards a small fraction of the global population. Information and Communication Technology (ICT) is culture-sensitive and this is a dynamic that is largely ignored in the majority of ICT for Development (ICT4D) interventions, leading to the technological determinism flaw and ultimately a failure of the undertaken projects. The deployment of ICT solutions, in particular in the context of ICT4D, must be informed by the cultural and socio-technical profile of the deployment environments and solutions themselves must be developed with a focus towards context-sensitivity and ethnocentricity. In this thesis, we investigate the viability of a software architectural framework for the development of ICT solutions that are context-sensitive and ethnocentric1, and so aligned with the cultural and social dynamics within the environment of deployment. The conceptual framework, named PIASK, defines five tiers (presentation, interaction, access, social networking, and knowledge base) which allow for: behavioural completeness of the layer components; a modular and functionally decoupled architecture; and the flexibility to situate and contextualize the developed applications along the dimensions of the User Interface (UI), interaction modalities, usage metaphors, underlying Indigenous Knowledge (IK), and access protocols. We have developed a proof-of-concept service platform, called KnowNet, based on the PIASK architecture. KnowNet is built around the knowledge base layer, which consists of domain ontologies that encapsulate the knowledge in the platform, with an intrinsic flexibility to access secondary knowledge repositories. The domain ontologies constructed (as examples) are for the provisioning of eServices to support societal activities (e.g. commerce, health, agriculture, medicine) within a rural and marginalized area of Dwesa, in the Eastern Cape province of South Africa. The social networking layer allows for situating the platform within the local social systems. Heterogeneity of user profiles and multiplicity of end-user devices are handled through the access and the presentation components, and the service logic is implemented by the interaction components. This services platform validates the PIASK architecture for end-to-end provisioning of multi-modal, heterogeneous, ontology-based services. The development of KnowNet was informed on one hand by the latest trends within service architectures, semantic web technologies and social applications, and on the other hand by the context consideration based on the profile (IK systems dynamics, infrastructure, usability requirements) of the Dwesa community. The realization of the service platform is based on the JADE Multi-Agent System (MAS), and this shows the applicability and adequacy of MAS’s for service deployment in a rural context, at the same time providing key advantages such as platform fault-tolerance, robustness and flexibility. While the context of conceptualization of PIASK and the implementation of KnowNet is that of rurality and of ICT4D, the applicability of the architecture extends to other similarly heterogeneous and context-sensitive domains. KnowNet has been validated for functional and technical adequacy, and we have also undertaken an initial prevalidation for social context sensitivity. We observe that the five tier PIASK architecture provides an adequate framework for developing context-sensitive and ethnocentric software: by functionally separating and making explicit the social networking and access tier components, while still maintaining the traditional separation of presentation, business logic and data components.
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Network-layer reservation TDM for ad-hoc 802.11 networks
- Authors: Duff, Kevin Craig
- Date: 2008
- Subjects: Computer networks -- Access control , Computers -- Access control , Computer networks -- Management , Time division multiple access , Ad hoc networks (Computer networks)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4574 , http://hdl.handle.net/10962/d1002773 , Computer networks -- Access control , Computers -- Access control , Computer networks -- Management , Time division multiple access , Ad hoc networks (Computer networks)
- Description: Ad-Hoc mesh networks offer great promise. Low-cost ad-hoc mesh networks can be built using popular IEEE 802.11 equipment, but such networks are unable to guarantee each node a fair share of bandwidth. Furthermore, hidden node problems cause collisions which can cripple the throughput of a network. This research proposes a novel mechanism which is able to overcome hidden node problems and provide fair bandwidth sharing among nodes on ad-hoc 802.11 networks, and can be implemented on existing network devices. The scheme uses TDM (time division multiplexing) with slot reservation. A distributed beacon packet latency measurement mechanism is used to achieve node synchronisation. The distributed nature of the mechanism makes it applicable to ad-hoc 802.11 networks, which can either grow or fragment dynamically.
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- Authors: Duff, Kevin Craig
- Date: 2008
- Subjects: Computer networks -- Access control , Computers -- Access control , Computer networks -- Management , Time division multiple access , Ad hoc networks (Computer networks)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4574 , http://hdl.handle.net/10962/d1002773 , Computer networks -- Access control , Computers -- Access control , Computer networks -- Management , Time division multiple access , Ad hoc networks (Computer networks)
- Description: Ad-Hoc mesh networks offer great promise. Low-cost ad-hoc mesh networks can be built using popular IEEE 802.11 equipment, but such networks are unable to guarantee each node a fair share of bandwidth. Furthermore, hidden node problems cause collisions which can cripple the throughput of a network. This research proposes a novel mechanism which is able to overcome hidden node problems and provide fair bandwidth sharing among nodes on ad-hoc 802.11 networks, and can be implemented on existing network devices. The scheme uses TDM (time division multiplexing) with slot reservation. A distributed beacon packet latency measurement mechanism is used to achieve node synchronisation. The distributed nature of the mechanism makes it applicable to ad-hoc 802.11 networks, which can either grow or fragment dynamically.
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Prototyping a peer-to-peer session initiation protocol user agent
- Authors: Tsietsi, Mosiuoa Jeremia
- Date: 2008 , 2008-03-10
- Subjects: Computer networks , Computer network protocols -- Standards , Data transmission systems -- Standards , Peer-to-peer architecture (Computer networks) , Computer network architectures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4646 , http://hdl.handle.net/10962/d1006603 , Computer networks , Computer network protocols -- Standards , Data transmission systems -- Standards , Peer-to-peer architecture (Computer networks) , Computer network architectures
- Description: The Session Initiation Protocol (SIP) has in recent years become a popular protocol for the exchange of text, voice and video over IP networks. This thesis proposes the use of a class of structured peer to peer protocols - commonly known as Distributed Hash Tables (DHTs) - to provide a SIP overlay with services such as end-point location management and message relay, in the absence of traditional, centralised resources such as SIP proxies and registrars. A peer-to-peer layer named OverCord, which allows the interaction with any specific DHT protocol via the use of appropriate plug-ins, was designed, implemented and tested. This layer was then incorporated into a SIP user agent distributed by NIST (National Institute of Standards and Technology, USA). The modified user agent is capable of reliably establishing text, audio and video communication with similarly modified agents (peers) as well as conventional, centralized SIP overlays.
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- Authors: Tsietsi, Mosiuoa Jeremia
- Date: 2008 , 2008-03-10
- Subjects: Computer networks , Computer network protocols -- Standards , Data transmission systems -- Standards , Peer-to-peer architecture (Computer networks) , Computer network architectures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4646 , http://hdl.handle.net/10962/d1006603 , Computer networks , Computer network protocols -- Standards , Data transmission systems -- Standards , Peer-to-peer architecture (Computer networks) , Computer network architectures
- Description: The Session Initiation Protocol (SIP) has in recent years become a popular protocol for the exchange of text, voice and video over IP networks. This thesis proposes the use of a class of structured peer to peer protocols - commonly known as Distributed Hash Tables (DHTs) - to provide a SIP overlay with services such as end-point location management and message relay, in the absence of traditional, centralised resources such as SIP proxies and registrars. A peer-to-peer layer named OverCord, which allows the interaction with any specific DHT protocol via the use of appropriate plug-ins, was designed, implemented and tested. This layer was then incorporated into a SIP user agent distributed by NIST (National Institute of Standards and Technology, USA). The modified user agent is capable of reliably establishing text, audio and video communication with similarly modified agents (peers) as well as conventional, centralized SIP overlays.
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A model for a context aware machine-based personal memory manager and its implementation using a visual programming environment
- Authors: Tsegaye, Melekam Asrat
- Date: 2007
- Subjects: Visual programming (Computer science) Memory management (Computer science) Memory -- Data processing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4640 , http://hdl.handle.net/10962/d1006563
- Description: Memory is a part of cognition. It is essential for an individual to function normally in society. It encompasses an individual's lifetime experience, thus defining his identity. This thesis develops the concept of a machine-based personal memory manager which captures and manages an individual's day-to-day external memories. Rather than accumulating large amounts of data which has to be mined for useful memories, the machine-based memory manager automatically organizes memories as they are captured to enable their quick retrieval and use. The main functions of the machine-based memory manager envisioned in this thesis are the support and the augmentation of an individual's biological memory system. In the thesis, a model for a machine-based memory manager is developed. A visual programming environment, which can be used to build context aware applications as well as a proof-of-concept machine-based memory manager, is conceptualized and implemented. An experimental machine-based memory manager is implemented and evaluated. The model describes a machine-based memory manager which manages an individual's external memories by context. It addresses the management of external memories which accumulate over long periods of time by proposing a context aware file system which automatically organizes external memories by context. It describes how personal memory management can be facilitated by machine using six entities (life streams, memory producers, memory consumers, a memory manager, memory fragments and context descriptors) and the processes in which these entities participate (memory capture, memory encoding and decoding, memory decoding and retrieval). The visual programming environment represents a development tool which contains facilities that support context aware application programming. For example, it provides facilities which enable the definition and use of virtual sensors. It enables rapid programming with a focus on component re-use and dynamic composition of applications through a visual interface. The experimental machine-based memory manager serves as an example implementation of the machine-based memory manager which is described by the model developed in this thesis. The hardware used in its implementation consists of widely available components such as a camera, microphone and sub-notebook computer which are assembled in the form of a wearable computer. The software is constructed using the visual programming environment developed in this thesis. It contains multiple sensor drivers, context interpreters, a context aware file system as well as memory retrieval and presentation interfaces. The evaluation of the machine-based memory manager shows that it is possible to create a machine which monitors the states of an individual and his environment, and manages his external memories, thus supporting and augmenting his biological memory.
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- Authors: Tsegaye, Melekam Asrat
- Date: 2007
- Subjects: Visual programming (Computer science) Memory management (Computer science) Memory -- Data processing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4640 , http://hdl.handle.net/10962/d1006563
- Description: Memory is a part of cognition. It is essential for an individual to function normally in society. It encompasses an individual's lifetime experience, thus defining his identity. This thesis develops the concept of a machine-based personal memory manager which captures and manages an individual's day-to-day external memories. Rather than accumulating large amounts of data which has to be mined for useful memories, the machine-based memory manager automatically organizes memories as they are captured to enable their quick retrieval and use. The main functions of the machine-based memory manager envisioned in this thesis are the support and the augmentation of an individual's biological memory system. In the thesis, a model for a machine-based memory manager is developed. A visual programming environment, which can be used to build context aware applications as well as a proof-of-concept machine-based memory manager, is conceptualized and implemented. An experimental machine-based memory manager is implemented and evaluated. The model describes a machine-based memory manager which manages an individual's external memories by context. It addresses the management of external memories which accumulate over long periods of time by proposing a context aware file system which automatically organizes external memories by context. It describes how personal memory management can be facilitated by machine using six entities (life streams, memory producers, memory consumers, a memory manager, memory fragments and context descriptors) and the processes in which these entities participate (memory capture, memory encoding and decoding, memory decoding and retrieval). The visual programming environment represents a development tool which contains facilities that support context aware application programming. For example, it provides facilities which enable the definition and use of virtual sensors. It enables rapid programming with a focus on component re-use and dynamic composition of applications through a visual interface. The experimental machine-based memory manager serves as an example implementation of the machine-based memory manager which is described by the model developed in this thesis. The hardware used in its implementation consists of widely available components such as a camera, microphone and sub-notebook computer which are assembled in the form of a wearable computer. The software is constructed using the visual programming environment developed in this thesis. It contains multiple sensor drivers, context interpreters, a context aware file system as well as memory retrieval and presentation interfaces. The evaluation of the machine-based memory manager shows that it is possible to create a machine which monitors the states of an individual and his environment, and manages his external memories, thus supporting and augmenting his biological memory.
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Securing media streams in an Asterisk-based environment and evaluating the resulting performance cost
- Authors: Clayton, Bradley
- Date: 2007 , 2007-01-08
- Subjects: Asterisk (Computer file) , Computer networks -- Security measures , Internet telephony -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4647 , http://hdl.handle.net/10962/d1006606 , Asterisk (Computer file) , Computer networks -- Security measures , Internet telephony -- Security measures
- Description: When adding Confidentiality, Integrity and Availability (CIA) to a multi-user VoIP (Voice over IP) system, performance and quality are at risk. The aim of this study is twofold. Firstly, it describes current methods suitable to secure voice streams within a VoIP system and make them available in an Asterisk-based VoIP environment. (Asterisk is a well established, open-source, TDM/VoIP PBX.) Secondly, this study evaluates the performance cost incurred after implementing each security method within the Asterisk-based system, using a special testbed suite, named DRAPA, which was developed expressly for this study. The three security methods implemented and studied were IPSec (Internet Protocol Security), SRTP (Secure Real-time Transport Protocol), and SIAX2 (Secure Inter-Asterisk eXchange 2 protocol). From the experiments, it was found that bandwidth and CPU usage were significantly affected by the addition of CIA. In ranking the three security methods in terms of these two resources, it was found that SRTP incurs the least bandwidth overhead, followed by SIAX2 and then IPSec. Where CPU utilisation is concerned, it was found that SIAX2 incurs the least overhead, followed by IPSec, and then SRTP.
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- Authors: Clayton, Bradley
- Date: 2007 , 2007-01-08
- Subjects: Asterisk (Computer file) , Computer networks -- Security measures , Internet telephony -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4647 , http://hdl.handle.net/10962/d1006606 , Asterisk (Computer file) , Computer networks -- Security measures , Internet telephony -- Security measures
- Description: When adding Confidentiality, Integrity and Availability (CIA) to a multi-user VoIP (Voice over IP) system, performance and quality are at risk. The aim of this study is twofold. Firstly, it describes current methods suitable to secure voice streams within a VoIP system and make them available in an Asterisk-based VoIP environment. (Asterisk is a well established, open-source, TDM/VoIP PBX.) Secondly, this study evaluates the performance cost incurred after implementing each security method within the Asterisk-based system, using a special testbed suite, named DRAPA, which was developed expressly for this study. The three security methods implemented and studied were IPSec (Internet Protocol Security), SRTP (Secure Real-time Transport Protocol), and SIAX2 (Secure Inter-Asterisk eXchange 2 protocol). From the experiments, it was found that bandwidth and CPU usage were significantly affected by the addition of CIA. In ranking the three security methods in terms of these two resources, it was found that SRTP incurs the least bandwidth overhead, followed by SIAX2 and then IPSec. Where CPU utilisation is concerned, it was found that SIAX2 incurs the least overhead, followed by IPSec, and then SRTP.
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Securing softswitches from malicious attacks
- Authors: Opie, Jake Weyman
- Date: 2007
- Subjects: Internet telephony -- Security measures , Computer networks -- Security measures , Digital telephone systems , Communication -- Technological innovations , Computer network protocols , TCP/IP (Computer network protocol) , Switching theory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4683 , http://hdl.handle.net/10962/d1007714 , Internet telephony -- Security measures , Computer networks -- Security measures , Digital telephone systems , Communication -- Technological innovations , Computer network protocols , TCP/IP (Computer network protocol) , Switching theory
- Description: Traditionally, real-time communication, such as voice calls, has run on separate, closed networks. Of all the limitations that these networks had, the ability of malicious attacks to cripple communication was not a crucial one. This situation has changed radically now that real-time communication and data have merged to share the same network. The objective of this project is to investigate the securing of softswitches with functionality similar to Private Branch Exchanges (PBX) from malicious attacks. The focus of the project will be a practical investigation of how to secure ILANGA, an ASTERISK-based system under development at Rhodes University. The practical investigation that focuses on ILANGA is based on performing six varied experiments on the different components of ILANGA. Before the six experiments are performed, basic preliminary security measures and the restrictions placed on the access to the database are discussed. The outcomes of these experiments are discussed and the precise reasons why these attacks were either successful or unsuccessful are given. Suggestions of a theoretical nature on how to defend against the successful attacks are also presented.
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- Authors: Opie, Jake Weyman
- Date: 2007
- Subjects: Internet telephony -- Security measures , Computer networks -- Security measures , Digital telephone systems , Communication -- Technological innovations , Computer network protocols , TCP/IP (Computer network protocol) , Switching theory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4683 , http://hdl.handle.net/10962/d1007714 , Internet telephony -- Security measures , Computer networks -- Security measures , Digital telephone systems , Communication -- Technological innovations , Computer network protocols , TCP/IP (Computer network protocol) , Switching theory
- Description: Traditionally, real-time communication, such as voice calls, has run on separate, closed networks. Of all the limitations that these networks had, the ability of malicious attacks to cripple communication was not a crucial one. This situation has changed radically now that real-time communication and data have merged to share the same network. The objective of this project is to investigate the securing of softswitches with functionality similar to Private Branch Exchanges (PBX) from malicious attacks. The focus of the project will be a practical investigation of how to secure ILANGA, an ASTERISK-based system under development at Rhodes University. The practical investigation that focuses on ILANGA is based on performing six varied experiments on the different components of ILANGA. Before the six experiments are performed, basic preliminary security measures and the restrictions placed on the access to the database are discussed. The outcomes of these experiments are discussed and the precise reasons why these attacks were either successful or unsuccessful are given. Suggestions of a theoretical nature on how to defend against the successful attacks are also presented.
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Decorating Asterisk : experiments in service creation for a multi-protocol telephony environment using open source tools
- Authors: Hitchcock, Jonathan
- Date: 2006
- Subjects: Asterisk (Computer file) , Internet telephony
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4635 , http://hdl.handle.net/10962/d1006539 , Asterisk (Computer file) , Internet telephony
- Description: As Voice over IP becomes more prevalent, value-adds to the service will become ubiquitous. Voice over IP (VoIP) is no longer a single service application, but an array of marketable services of increasing depth, which are moving into the non-desktop market. In addition, as the range of devices being generally used increases, it will become necessary for all services, including VoIP services, to be accessible from multiple platforms and through varied interfaces. With the recent introduction and growth of the open source software PBX system named Asterisk, the possibility of achieving these goals has become more concrete. In addition to Asterisk, a number of open source systems are being developed which facilitate the development of systems that interoperate over a wide variety of platforms and through multiple interfaces. This thesis investigates Asterisk in terms of its viability to provide the depth of services that will be required in a VoIP environment, as well as a number of other open source systems in terms of what they can offer such a system. In addition, it investigates whether these services can be made available on different devices. Using various systems built as a proof-of-concept, this thesis shows that Asterisk, in conjunction with various other open source projects, such as the Twisted framework provides a concrete tool which can be used to realise flexible and protocol independent telephony solutions for a small to medium enterprise.
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- Authors: Hitchcock, Jonathan
- Date: 2006
- Subjects: Asterisk (Computer file) , Internet telephony
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4635 , http://hdl.handle.net/10962/d1006539 , Asterisk (Computer file) , Internet telephony
- Description: As Voice over IP becomes more prevalent, value-adds to the service will become ubiquitous. Voice over IP (VoIP) is no longer a single service application, but an array of marketable services of increasing depth, which are moving into the non-desktop market. In addition, as the range of devices being generally used increases, it will become necessary for all services, including VoIP services, to be accessible from multiple platforms and through varied interfaces. With the recent introduction and growth of the open source software PBX system named Asterisk, the possibility of achieving these goals has become more concrete. In addition to Asterisk, a number of open source systems are being developed which facilitate the development of systems that interoperate over a wide variety of platforms and through multiple interfaces. This thesis investigates Asterisk in terms of its viability to provide the depth of services that will be required in a VoIP environment, as well as a number of other open source systems in terms of what they can offer such a system. In addition, it investigates whether these services can be made available on different devices. Using various systems built as a proof-of-concept, this thesis shows that Asterisk, in conjunction with various other open source projects, such as the Twisted framework provides a concrete tool which can be used to realise flexible and protocol independent telephony solutions for a small to medium enterprise.
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Models of internet connectivity for secondary schools in the Grahamstown circuit
- Authors: Brandt, Ingrid Gisélle
- Date: 2006
- Subjects: Internet in education -- South Africa -- Grahamstown , Computer networks -- South Africa -- Grahamstown , Information technology -- Study and teaching (Secondary) -- South Africa -- Grahamstown , Information technology -- South Africa -- Grahamstown , Computer-assisted instruction -- South Africa -- Grahamstown , Telecommunication in education -- South Africa -- Grahamstown , Education, Secondary -- South Africa -- Grahamstown -- Data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4641 , http://hdl.handle.net/10962/d1006566 , Internet in education -- South Africa -- Grahamstown , Computer networks -- South Africa -- Grahamstown , Information technology -- Study and teaching (Secondary) -- South Africa -- Grahamstown , Information technology -- South Africa -- Grahamstown , Computer-assisted instruction -- South Africa -- Grahamstown , Telecommunication in education -- South Africa -- Grahamstown , Education, Secondary -- South Africa -- Grahamstown -- Data processing
- Description: Information and Communication Technologies (ICTs) are becoming more pervasive in South African schools and are increasingly considered valuable tools in education, promoting the development of higher cognitive processes and allowing teachers and learners access to a plethora of information. This study investigates models of Internet connectivity for secondary schools in the Grahamstown Circuit. The various networking technologies currently available to South African schools, or likely to become available to South African schools in the future, are described along with the telecommunications legislation which governs their use in South Africa. Furthermore, current ICT in education projects taking place in South Africa are described together with current ICT in education policy in South Africa. This information forms the backdrop of a detailed schools survey that was conducted at all the 13 secondary schools in the Grahamstown Circuit and enriched with experimental work in the provision of metropolitan network links to selected schools, mostly via Wi-Fi. The result of the investigation is the proposal of a Grahamstown Circuit Metropolitan Education Network.
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- Authors: Brandt, Ingrid Gisélle
- Date: 2006
- Subjects: Internet in education -- South Africa -- Grahamstown , Computer networks -- South Africa -- Grahamstown , Information technology -- Study and teaching (Secondary) -- South Africa -- Grahamstown , Information technology -- South Africa -- Grahamstown , Computer-assisted instruction -- South Africa -- Grahamstown , Telecommunication in education -- South Africa -- Grahamstown , Education, Secondary -- South Africa -- Grahamstown -- Data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4641 , http://hdl.handle.net/10962/d1006566 , Internet in education -- South Africa -- Grahamstown , Computer networks -- South Africa -- Grahamstown , Information technology -- Study and teaching (Secondary) -- South Africa -- Grahamstown , Information technology -- South Africa -- Grahamstown , Computer-assisted instruction -- South Africa -- Grahamstown , Telecommunication in education -- South Africa -- Grahamstown , Education, Secondary -- South Africa -- Grahamstown -- Data processing
- Description: Information and Communication Technologies (ICTs) are becoming more pervasive in South African schools and are increasingly considered valuable tools in education, promoting the development of higher cognitive processes and allowing teachers and learners access to a plethora of information. This study investigates models of Internet connectivity for secondary schools in the Grahamstown Circuit. The various networking technologies currently available to South African schools, or likely to become available to South African schools in the future, are described along with the telecommunications legislation which governs their use in South Africa. Furthermore, current ICT in education projects taking place in South Africa are described together with current ICT in education policy in South Africa. This information forms the backdrop of a detailed schools survey that was conducted at all the 13 secondary schools in the Grahamstown Circuit and enriched with experimental work in the provision of metropolitan network links to selected schools, mostly via Wi-Fi. The result of the investigation is the proposal of a Grahamstown Circuit Metropolitan Education Network.
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Design of a performance evaluation tool for multimedia databases with special reference to Oracle
- Authors: Stakemire, Tonia
- Date: 2004
- Subjects: Oracle (Computer file) , Application software -- Evaluation , Database management -- Evaluation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4705 , http://hdl.handle.net/10962/d1015975
- Description: Increased production and use of multimedia data has led to the development of a more advanced Database Management System (DBMS), like an Object Relational Database Management System (ORDBMS). These advanced databases are necessitated by the complexity in structure and the functionality required by multimedia data. Unfortunately, no suitable benchmarks exist with which to test the performance of databases when handling multimedia data. This thesis describes the design of a benchmark to measure the performance of basic functionality found in multimedia databases. The benchmark, called MORD (Multimedia Object Relational Databases), targets Oracle, a well known commercial Object Relational Database Management System (ORDBMS) that can handle multimedia data. Although MORD targets Oracle, it can easily be applied to other Multimedia Database Management System (MMDBMS) as a result of a design that stressed its portability, and simplicity. MORD consists of a database schema, test data, and code to simulate representative queries on multimedia databases. A number of experiments are described that validate MORD and ensure its correct design and that its objectives are met. A by-product of these experiments is an initial understanding of the performance of multimedia databases. The experiments show that with multimedia data the buffer cache should be at least large enough to hold the largest dataset, a bigger block size improves the performance, and turning off logging and caching for bulk loading improves the performance. MORD can be used to compare different ORDBMS or to assist in the configuration of a specific database.
- Full Text:
- Authors: Stakemire, Tonia
- Date: 2004
- Subjects: Oracle (Computer file) , Application software -- Evaluation , Database management -- Evaluation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4705 , http://hdl.handle.net/10962/d1015975
- Description: Increased production and use of multimedia data has led to the development of a more advanced Database Management System (DBMS), like an Object Relational Database Management System (ORDBMS). These advanced databases are necessitated by the complexity in structure and the functionality required by multimedia data. Unfortunately, no suitable benchmarks exist with which to test the performance of databases when handling multimedia data. This thesis describes the design of a benchmark to measure the performance of basic functionality found in multimedia databases. The benchmark, called MORD (Multimedia Object Relational Databases), targets Oracle, a well known commercial Object Relational Database Management System (ORDBMS) that can handle multimedia data. Although MORD targets Oracle, it can easily be applied to other Multimedia Database Management System (MMDBMS) as a result of a design that stressed its portability, and simplicity. MORD consists of a database schema, test data, and code to simulate representative queries on multimedia databases. A number of experiments are described that validate MORD and ensure its correct design and that its objectives are met. A by-product of these experiments is an initial understanding of the performance of multimedia databases. The experiments show that with multimedia data the buffer cache should be at least large enough to hold the largest dataset, a bigger block size improves the performance, and turning off logging and caching for bulk loading improves the performance. MORD can be used to compare different ORDBMS or to assist in the configuration of a specific database.
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An empirical, in-depth investigation into service creation in H.323 Version 4 Networks
- Authors: Penton, Jason Barry
- Date: 2003 , 2013-05-24
- Subjects: Computer programming , Computer networks , Computer network protocols
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4681 , http://hdl.handle.net/10962/d1007637 , Computer programming , Computer networks , Computer network protocols
- Description: Over the past few years there has been an increasing tendency to carry voice on IP networks as opposed to the PSTN and other switched circuit networks. Initially this trend was favoured due to reduced costs but occurred at the expense of sacrificing the quality of the voice communications. Switched circuit networks have therefore remained the preferred carrier-grade voice communication network, but this is again changing. The advancement in improved quality of service (QoS) of real-time traffic on the IP network is a contributing factor to the anticipated future of the IP network supplying carrier-grade voice communications. Another contributing factor is the possibility of creating a new range of innovative, state-of-the-art telephony and communications services that acquire leverage through the intelligence and flexibility of the IP network. The latter has yet to be fully explored. Various protocols exist that facilitate the transport of voice and other media on IP networks. The most well known and widely supported of these is H.323. This work presents and discusses H.323 version 4 service creation. The work also categorises the various H.323 services and presents the mechanisms provided by H.323 version 4 that have facilitated the development of the three services I have developed, EmailReader, Telgo323 and CANS.
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- Authors: Penton, Jason Barry
- Date: 2003 , 2013-05-24
- Subjects: Computer programming , Computer networks , Computer network protocols
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4681 , http://hdl.handle.net/10962/d1007637 , Computer programming , Computer networks , Computer network protocols
- Description: Over the past few years there has been an increasing tendency to carry voice on IP networks as opposed to the PSTN and other switched circuit networks. Initially this trend was favoured due to reduced costs but occurred at the expense of sacrificing the quality of the voice communications. Switched circuit networks have therefore remained the preferred carrier-grade voice communication network, but this is again changing. The advancement in improved quality of service (QoS) of real-time traffic on the IP network is a contributing factor to the anticipated future of the IP network supplying carrier-grade voice communications. Another contributing factor is the possibility of creating a new range of innovative, state-of-the-art telephony and communications services that acquire leverage through the intelligence and flexibility of the IP network. The latter has yet to be fully explored. Various protocols exist that facilitate the transport of voice and other media on IP networks. The most well known and widely supported of these is H.323. This work presents and discusses H.323 version 4 service creation. The work also categorises the various H.323 services and presents the mechanisms provided by H.323 version 4 that have facilitated the development of the three services I have developed, EmailReader, Telgo323 and CANS.
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A framework for interpreting noisy, two-dimensional images, based on a fuzzification of programmed, attributed graph grammars
- Authors: Watkins, Gregory Shroll
- Date: 1998
- Subjects: Music -- Data processing Computer sound processing Artificial intelligence -- Musical applications Fuzzy systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4604 , http://hdl.handle.net/10962/d1004862
- Description: This thesis investigates a fuzzy syntactic approach to the interpretation of noisy two-dimensional images. This approach is based on a modification of the attributed graph grammar formalism to utilise fuzzy membership functions in the applicability predicates. As far as we are aware, this represents the first such modification of graph grammars. Furthermore, we develop a method for programming the resultant fuzzy attributed graph grammars through the use of non-deterministic control diagrams. To do this, we modify the standard programming mechanism to allow it to cope with the fuzzy certainty values associated with productions in our grammar. Our objective was to develop a flexible framework which can be used for the recognition of a wide variety of image classes, and which is adept at dealing with noise in these images. Programmed graph grammars are specifically chosen for the ease with which they allow one to specify a new two-dimensional image class. We implement a prototype system for Optical Music Recognition using our framework. This system allows us to test the capabilities of the framework for coping with noise in the context of handwritten music score recognition. Preliminary results from the prototype system show that the framework copes well with noisy images.
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- Authors: Watkins, Gregory Shroll
- Date: 1998
- Subjects: Music -- Data processing Computer sound processing Artificial intelligence -- Musical applications Fuzzy systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4604 , http://hdl.handle.net/10962/d1004862
- Description: This thesis investigates a fuzzy syntactic approach to the interpretation of noisy two-dimensional images. This approach is based on a modification of the attributed graph grammar formalism to utilise fuzzy membership functions in the applicability predicates. As far as we are aware, this represents the first such modification of graph grammars. Furthermore, we develop a method for programming the resultant fuzzy attributed graph grammars through the use of non-deterministic control diagrams. To do this, we modify the standard programming mechanism to allow it to cope with the fuzzy certainty values associated with productions in our grammar. Our objective was to develop a flexible framework which can be used for the recognition of a wide variety of image classes, and which is adept at dealing with noise in these images. Programmed graph grammars are specifically chosen for the ease with which they allow one to specify a new two-dimensional image class. We implement a prototype system for Optical Music Recognition using our framework. This system allows us to test the capabilities of the framework for coping with noise in the context of handwritten music score recognition. Preliminary results from the prototype system show that the framework copes well with noisy images.
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