Extensibility in ORDBMS databases : an exploration of the data cartridge mechanism in Oracle9i
- Ndakunda, Tulimevava Kaunapawa
- Authors: Ndakunda, Tulimevava Kaunapawa
- Date: 2013-06-18
- Subjects: Database management , Oracle (Computer file)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4686 , http://hdl.handle.net/10962/d1008098 , Database management , Oracle (Computer file)
- Description: To support current and emerging database applications, Object-Relational Database Management Systems (ORDBMS) provide mechanisms to extend the data storage capabilities and the functionality of the database with application-specific types and methods. Using these mechanisms, the database may contain user-defined data types, large objects (LOBs), external procedures, extensible indexing, query optimisation techniques and other features that are treated in the same way as built-in database features . The many extensibility options provided by the ORDBMS, however, raise several implementation challenges that are not always obvious. This thesis examines a few of the key challenges that arise when extending Oracle database with new functionality. To realise the potential of extensibility in Oracle, the thesis used the problem area of image retrieval as the main test domain. Current research efforts in image retrieval are lagging behind the required retrieval, but are continuously improving. As better retrieval techniques become available, it is important that they are integrated into the available database systems to facilitate improved retrieval. The thesis also reports on the practical experiences gained from integrating an extensible indexing scenario. Sample scenarios are integrated in Oracle9i database using the data cartridge mechanism, which allows Oracle database functionality to be extended with new functional components. The integration demonstrates how additional functionality may be effectively applied to both general and specialised domains in the database. It also reveals alternative design options that allow data cartridge developers, most of who are not database server experts, to extend the database. The thesis is concluded with some of the key observations and options that designers must consider when extending the database with new functionality. The main challenges for developers are the learning curve required to understand the data cartridge framework and the ability to adapt already developed code within the constraints of the data cartridge using the provided extensibility APls. Maximum reusability relies on making good choices for the basic functions, out of which specialised functions can be built. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Ndakunda, Tulimevava Kaunapawa
- Date: 2013-06-18
- Subjects: Database management , Oracle (Computer file)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4686 , http://hdl.handle.net/10962/d1008098 , Database management , Oracle (Computer file)
- Description: To support current and emerging database applications, Object-Relational Database Management Systems (ORDBMS) provide mechanisms to extend the data storage capabilities and the functionality of the database with application-specific types and methods. Using these mechanisms, the database may contain user-defined data types, large objects (LOBs), external procedures, extensible indexing, query optimisation techniques and other features that are treated in the same way as built-in database features . The many extensibility options provided by the ORDBMS, however, raise several implementation challenges that are not always obvious. This thesis examines a few of the key challenges that arise when extending Oracle database with new functionality. To realise the potential of extensibility in Oracle, the thesis used the problem area of image retrieval as the main test domain. Current research efforts in image retrieval are lagging behind the required retrieval, but are continuously improving. As better retrieval techniques become available, it is important that they are integrated into the available database systems to facilitate improved retrieval. The thesis also reports on the practical experiences gained from integrating an extensible indexing scenario. Sample scenarios are integrated in Oracle9i database using the data cartridge mechanism, which allows Oracle database functionality to be extended with new functional components. The integration demonstrates how additional functionality may be effectively applied to both general and specialised domains in the database. It also reveals alternative design options that allow data cartridge developers, most of who are not database server experts, to extend the database. The thesis is concluded with some of the key observations and options that designers must consider when extending the database with new functionality. The main challenges for developers are the learning curve required to understand the data cartridge framework and the ability to adapt already developed code within the constraints of the data cartridge using the provided extensibility APls. Maximum reusability relies on making good choices for the basic functions, out of which specialised functions can be built. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
Developing a cross platform IMS client using the JAIN SIP applet phone
- Authors: Muswera, Walter Tawanda
- Date: 2015
- Subjects: Internet Protocol multimedia subsystem , Java (Computer program language)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4712 , http://hdl.handle.net/10962/d1017934
- Description: Since the introduction of the IP Multimedia Subsystem (IMS) by the Third Generation Partnership Project (3GPP) in 2002, a lot of research has been conducted aimed at designing and implementing IMS capable clients and network elements. Though considerable work has been done in the development of IMS clients, there is no single, free and open source IMS client that provides researchers with all the required functionality needed to test the applications they are developing. For example, several open and closed source SIP/IMS clients are used within the Rhodes University Conver- gence Research Group (RUCRG) to test applications under development, as a result of the fact that the various SIP/IMS clients support different subsets of SIP/IMS features. The lack of a single client and the subsequent use of various clients comes with several problems. Researchers have to know how to deploy, configure, use and at times adapt the various clients to suit their needs. This can be very time consuming and, in fact, contradicts the IMS philosophy (the IMS was proposed to support rapid service creation). This thesis outlines the development of a Java-based, IMS compliant client called RUCRG IMS client, that uses the JAIN SIP Applet Phone (JSAP) as its foundation. JSAP, which originally offered only basic voice calling and instant messaging (IM) capabilities, was modified to be IMS compliant and support video calls, IM and presence using XML Configuration Access Protocol (XCAP).
- Full Text:
- Authors: Muswera, Walter Tawanda
- Date: 2015
- Subjects: Internet Protocol multimedia subsystem , Java (Computer program language)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4712 , http://hdl.handle.net/10962/d1017934
- Description: Since the introduction of the IP Multimedia Subsystem (IMS) by the Third Generation Partnership Project (3GPP) in 2002, a lot of research has been conducted aimed at designing and implementing IMS capable clients and network elements. Though considerable work has been done in the development of IMS clients, there is no single, free and open source IMS client that provides researchers with all the required functionality needed to test the applications they are developing. For example, several open and closed source SIP/IMS clients are used within the Rhodes University Conver- gence Research Group (RUCRG) to test applications under development, as a result of the fact that the various SIP/IMS clients support different subsets of SIP/IMS features. The lack of a single client and the subsequent use of various clients comes with several problems. Researchers have to know how to deploy, configure, use and at times adapt the various clients to suit their needs. This can be very time consuming and, in fact, contradicts the IMS philosophy (the IMS was proposed to support rapid service creation). This thesis outlines the development of a Java-based, IMS compliant client called RUCRG IMS client, that uses the JAIN SIP Applet Phone (JSAP) as its foundation. JSAP, which originally offered only basic voice calling and instant messaging (IM) capabilities, was modified to be IMS compliant and support video calls, IM and presence using XML Configuration Access Protocol (XCAP).
- Full Text:
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.
- Full Text:
- 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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A mobile toolkit and customised location server for the creation of cross-referencing location-based services
- Ndakunda, Shange-Ishiwa Tangeni
- Authors: Ndakunda, Shange-Ishiwa Tangeni
- Date: 2013
- Subjects: Location-based services -- Security measures , Mobile communication systems -- Security measures , Digital communications , Java (Computer program language) , Application software -- Development -- Computer programs , User interfaces (Computer systems)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4703 , http://hdl.handle.net/10962/d1013604
- Description: Although there are several Software Development kits and Application Programming Interfaces for client-side location-based services development, they mostly involve the creation of self-referencing location-based services. Self-referencing location-based services include services such as geocoding, reverse geocoding, route management and navigation which focus on satisfying the location-based requirements of a single mobile device. There is a lack of open-source Software Development Kits for the development of client-side location-based services that are cross-referencing. Cross-referencing location-based services are designed for the sharing of location information amongst different entities on a given network. This project was undertaken to assemble, through incremental prototyping, a client-side Java Micro Edition location-based services Software Development Kit and a Mobicents location server to aid mobile network operators and developers alike in the quick creation of the transport and privacy protection of cross-referencing location-based applications on Session Initiation Protocol bearer networks. The privacy of the location information is protected using geolocation policies. Developers do not need to have an understanding of Session Initiation Protocol event signaling specifications or of the XML Configuration Access Protocol to use the tools that we put together. The developed tools are later consolidated using two sample applications, the friend-finder and child-tracker services. Developer guidelines are also provided, to aid in using the provided tools.
- Full Text:
- Authors: Ndakunda, Shange-Ishiwa Tangeni
- Date: 2013
- Subjects: Location-based services -- Security measures , Mobile communication systems -- Security measures , Digital communications , Java (Computer program language) , Application software -- Development -- Computer programs , User interfaces (Computer systems)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4703 , http://hdl.handle.net/10962/d1013604
- Description: Although there are several Software Development kits and Application Programming Interfaces for client-side location-based services development, they mostly involve the creation of self-referencing location-based services. Self-referencing location-based services include services such as geocoding, reverse geocoding, route management and navigation which focus on satisfying the location-based requirements of a single mobile device. There is a lack of open-source Software Development Kits for the development of client-side location-based services that are cross-referencing. Cross-referencing location-based services are designed for the sharing of location information amongst different entities on a given network. This project was undertaken to assemble, through incremental prototyping, a client-side Java Micro Edition location-based services Software Development Kit and a Mobicents location server to aid mobile network operators and developers alike in the quick creation of the transport and privacy protection of cross-referencing location-based applications on Session Initiation Protocol bearer networks. The privacy of the location information is protected using geolocation policies. Developers do not need to have an understanding of Session Initiation Protocol event signaling specifications or of the XML Configuration Access Protocol to use the tools that we put together. The developed tools are later consolidated using two sample applications, the friend-finder and child-tracker services. Developer guidelines are also provided, to aid in using the provided tools.
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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.
- Full Text:
- 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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Building the field component of a smart irrigation system: A detailed experience of a computer science graduate
- Authors: Pipile, Yamnkelani Yonela
- Date: 2021-10
- Subjects: Irrigation efficiency Computer-aided design South Africa , Irrigation projects Computer-aided design South Africa , Internet of things , Machine-to-machine communications , Smart water grids South Africa , Raspberry Pi (Computer) , Arduino (Programmable controller) , ZigBee , MQTT (MQ Telemetry Transport) , MQTT-SN , XBee
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191814 , vital:45167
- Description: South Africa is a semi-arid area with an average annual rainfall of approximately 450mm, 60 per cent of which goes towards irrigation. Current irrigation systems generally apply water in a uniform manner across a field, which is both inefficient and can kill the plants. The Internet of Things (IoT), an emerging technology involving the utilization of sensors and actuators to build complex feedback systems, present an opportunity to build a smart irrigation solution. This research project illustrates the development of the field components of a water monitoring system using off the shelf and inexpensive components, exploring at the same time how easy or difficult it would be for a general Computer Science graduate to use hardware components and associated tools within the IoT area. The problem was initially broken down through a classical top-down process, in order to identify the components such as micro-computers, micro- controllers, sensors and network connections, that would be needed to build the solution. I then selected the Raspberry Pi 3, the Arduino Arduino Uno, the MH-Sensor-Series hygrometer, the MQTT messaging protocol, and the ZigBee communication protocol as implemented in the XBee S2C. Once the components were identified, the work followed a bottom-up approach: I studied the components in isolation and relative to each other, through a structured series of experiments, with each experiment addressing a specific component and examining how easy was to use the component. While each experiment allowed the author to acquire and deepen her understanding of each component, and progressively built a more sophisticated prototype, towards the complete solution. I found the vast majority of the identified components and tools to be easy to use, well documented, and most importantly, mature for consumption by our target user, until I encountered the MQTT-SN (MQTT-Sensor Network) implementation, not as mature as the rest. This resulted in us designing and implementing a light-weight, general ZigBee/MQTT gateway, named “yoGa” (Yonella's Gateway) from the author. At the end of the research, I was able to build the field components of a smart irrigation system using the selected tools, including the yoGa gateway, proving practically that a Computer Science graduate from a South African University can become productive in the emerging IoT area. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Authors: Pipile, Yamnkelani Yonela
- Date: 2021-10
- Subjects: Irrigation efficiency Computer-aided design South Africa , Irrigation projects Computer-aided design South Africa , Internet of things , Machine-to-machine communications , Smart water grids South Africa , Raspberry Pi (Computer) , Arduino (Programmable controller) , ZigBee , MQTT (MQ Telemetry Transport) , MQTT-SN , XBee
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191814 , vital:45167
- Description: South Africa is a semi-arid area with an average annual rainfall of approximately 450mm, 60 per cent of which goes towards irrigation. Current irrigation systems generally apply water in a uniform manner across a field, which is both inefficient and can kill the plants. The Internet of Things (IoT), an emerging technology involving the utilization of sensors and actuators to build complex feedback systems, present an opportunity to build a smart irrigation solution. This research project illustrates the development of the field components of a water monitoring system using off the shelf and inexpensive components, exploring at the same time how easy or difficult it would be for a general Computer Science graduate to use hardware components and associated tools within the IoT area. The problem was initially broken down through a classical top-down process, in order to identify the components such as micro-computers, micro- controllers, sensors and network connections, that would be needed to build the solution. I then selected the Raspberry Pi 3, the Arduino Arduino Uno, the MH-Sensor-Series hygrometer, the MQTT messaging protocol, and the ZigBee communication protocol as implemented in the XBee S2C. Once the components were identified, the work followed a bottom-up approach: I studied the components in isolation and relative to each other, through a structured series of experiments, with each experiment addressing a specific component and examining how easy was to use the component. While each experiment allowed the author to acquire and deepen her understanding of each component, and progressively built a more sophisticated prototype, towards the complete solution. I found the vast majority of the identified components and tools to be easy to use, well documented, and most importantly, mature for consumption by our target user, until I encountered the MQTT-SN (MQTT-Sensor Network) implementation, not as mature as the rest. This resulted in us designing and implementing a light-weight, general ZigBee/MQTT gateway, named “yoGa” (Yonella's Gateway) from the author. At the end of the research, I was able to build the field components of a smart irrigation system using the selected tools, including the yoGa gateway, proving practically that a Computer Science graduate from a South African University can become productive in the emerging IoT area. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
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.
- Full Text:
- 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.
- Full Text:
A review of the Siyakhula Living Lab’s network solution for Internet in marginalized communities
- Muchatibaya, Hilbert Munashe
- Authors: Muchatibaya, Hilbert Munashe
- Date: 2022-10-14
- Subjects: Information and communication technologies for development , Information technology South Africa , Access network , User experience , Local area networks (Computer networks) South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/364943 , vital:65664
- Description: Changes within Information and Communication Technology (ICT) over the past decade required a review of the network layer component deployed in the Siyakhula Living Lab (SLL), a long-term joint venture between the Telkom Centres of Excellence hosted at University of Fort Hare and Rhodes University in South Africa. The SLL overall solution for the sustainable internet in poor communities consists of three main components – the computing infrastructure layer, the network layer, and the e-services layer. At the core of the network layer is the concept of BI, a high-speed local area network realized through easy-to deploy wireless technologies that establish point-to-multipoint connections among schools within a limited geographical area. Schools within the broadband island become then Digital Access Nodes (DANs), with computing infrastructure that provides access to the network. The review, reported in this thesis, aimed at determining whether the model for the network layer was still able to meet the needs of marginalized communities in South Africa, given the recent changes in ICT. The research work used the living lab methodology – a grassroots, user-driven approach that emphasizes co-creation between the beneficiaries and external entities (researchers, industry partners and the government) - to do viability tests on the solution for the network component. The viability tests included lab and field experiments, to produce the qualitative and quantitative data needed to propose an updated blueprint. The results of the review found that the network topology used in the SLL’s network, the BI, is still viable, while WiMAX is now outdated. Also, the in-network web cache, Squid, is no longer effective, given the switch to HTTPS and the pervasive presence of advertising. The solution to the first issue is outdoor Wi-Fi, a proven solution easily deployable in grass-roots fashion. The second issue can be mitigated by leveraging Squid’s ‘bumping’ and splicing features; deploying a browser extension to make picture download optional; and using Pihole, a DNS sinkhole. Hopefully, the revised solution could become a component of South African Government’s broadband plan, “SA Connect”. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
- Full Text:
- Authors: Muchatibaya, Hilbert Munashe
- Date: 2022-10-14
- Subjects: Information and communication technologies for development , Information technology South Africa , Access network , User experience , Local area networks (Computer networks) South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/364943 , vital:65664
- Description: Changes within Information and Communication Technology (ICT) over the past decade required a review of the network layer component deployed in the Siyakhula Living Lab (SLL), a long-term joint venture between the Telkom Centres of Excellence hosted at University of Fort Hare and Rhodes University in South Africa. The SLL overall solution for the sustainable internet in poor communities consists of three main components – the computing infrastructure layer, the network layer, and the e-services layer. At the core of the network layer is the concept of BI, a high-speed local area network realized through easy-to deploy wireless technologies that establish point-to-multipoint connections among schools within a limited geographical area. Schools within the broadband island become then Digital Access Nodes (DANs), with computing infrastructure that provides access to the network. The review, reported in this thesis, aimed at determining whether the model for the network layer was still able to meet the needs of marginalized communities in South Africa, given the recent changes in ICT. The research work used the living lab methodology – a grassroots, user-driven approach that emphasizes co-creation between the beneficiaries and external entities (researchers, industry partners and the government) - to do viability tests on the solution for the network component. The viability tests included lab and field experiments, to produce the qualitative and quantitative data needed to propose an updated blueprint. The results of the review found that the network topology used in the SLL’s network, the BI, is still viable, while WiMAX is now outdated. Also, the in-network web cache, Squid, is no longer effective, given the switch to HTTPS and the pervasive presence of advertising. The solution to the first issue is outdoor Wi-Fi, a proven solution easily deployable in grass-roots fashion. The second issue can be mitigated by leveraging Squid’s ‘bumping’ and splicing features; deploying a browser extension to make picture download optional; and using Pihole, a DNS sinkhole. Hopefully, the revised solution could become a component of South African Government’s broadband plan, “SA Connect”. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
- Full Text:
A structural and functional specification of a SCIM for service interaction management and personalisation in the IMS
- Authors: Tsietsi, Mosiuoa Jeremia
- Date: 2012
- Subjects: Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4606 , http://hdl.handle.net/10962/d1004864 , Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Description: The Internet Protocol Multimedia Subsystem (IMS) is a component of the 3G mobile network that has been specified by standards development organisations such as the 3GPP (3rd Generation Partnership Project) and ETSI (European Telecommunication Standards Institute). IMS seeks to guarantee that the telecommunication network of the future provides subscribers with seamless access to services across disparate networks. In order to achieve this, it defines a service architecture that hosts application servers that provide subscribers with value added services. Typically, an application server bundles all the functionality it needs to execute the services it delivers, however this view is currently being challenged. It is now thought that services should be synthesised from simple building blocks called service capabilities. This decomposition would facilitate the re-use of service capabilities across multiple services and would support the creation of new services that could not have originally been conceived. The shift from monolithic services to those built from service capabilities poses a challenge to the current service model in IMS. To accommodate this, the 3GPP has defined an entity known as a service capability interaction manager (SCIM) that would be responsible for managing the interactions between service capabilities in order to realise complex services. Some of these interactions could potentially lead to undesirable results, which the SCIM must work to avoid. As an added requirement, it is believed that the network should allow policies to be applied to network services which the SCIM should be responsible for enforcing. At the time of writing, the functional and structural architecture of the SCIM has not yet been standardised. This thesis explores the current serv ice architecture of the IMS in detail. Proposals that address the structure and functions of the SCIM are carefully compared and contrasted. This investigation leads to the presentation of key aspects of the SCIM, and provides solutions that explain how it should interact with service capabilities, manage undesirable interactions and factor user and network operator policies into its execution model. A modified design of the IMS service layer that embeds the SCIM is subsequently presented and described. The design uses existing IMS protocols and requires no change in the behaviour of the standard IMS entities. In order to develop a testbed for experimental verification of the design, the identification of suitable software platforms was required. This thesis presents some of the most popular platforms currently used by developers such as the Open IMS Core and OpenSER, as well as an open source, Java-based, multimedia communication platform called Mobicents. As a precursor to the development of the SCIM, a converged multimedia service is presented that describes how a video streaming application that is leveraged by a web portal was implemented for an IMS testbed using Mobicents components. The Mobicents SIP Servlets container was subsequently used to model an initial prototype of the SCIM, using a mUlti-component telephony service to illustrate the proposed service execution model. The design focuses on SIP-based services only, but should also work for other types of IMS application servers as well.
- Full Text:
- Authors: Tsietsi, Mosiuoa Jeremia
- Date: 2012
- Subjects: Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4606 , http://hdl.handle.net/10962/d1004864 , Internet Protocol multimedia subsystem , Internet Protocol multimedia subsystem -- Specifications , Long-Term Evolution (Telecommunications) , European Telecommunications Standards Institute , Wireless communication systems , Multimedia communications
- Description: The Internet Protocol Multimedia Subsystem (IMS) is a component of the 3G mobile network that has been specified by standards development organisations such as the 3GPP (3rd Generation Partnership Project) and ETSI (European Telecommunication Standards Institute). IMS seeks to guarantee that the telecommunication network of the future provides subscribers with seamless access to services across disparate networks. In order to achieve this, it defines a service architecture that hosts application servers that provide subscribers with value added services. Typically, an application server bundles all the functionality it needs to execute the services it delivers, however this view is currently being challenged. It is now thought that services should be synthesised from simple building blocks called service capabilities. This decomposition would facilitate the re-use of service capabilities across multiple services and would support the creation of new services that could not have originally been conceived. The shift from monolithic services to those built from service capabilities poses a challenge to the current service model in IMS. To accommodate this, the 3GPP has defined an entity known as a service capability interaction manager (SCIM) that would be responsible for managing the interactions between service capabilities in order to realise complex services. Some of these interactions could potentially lead to undesirable results, which the SCIM must work to avoid. As an added requirement, it is believed that the network should allow policies to be applied to network services which the SCIM should be responsible for enforcing. At the time of writing, the functional and structural architecture of the SCIM has not yet been standardised. This thesis explores the current serv ice architecture of the IMS in detail. Proposals that address the structure and functions of the SCIM are carefully compared and contrasted. This investigation leads to the presentation of key aspects of the SCIM, and provides solutions that explain how it should interact with service capabilities, manage undesirable interactions and factor user and network operator policies into its execution model. A modified design of the IMS service layer that embeds the SCIM is subsequently presented and described. The design uses existing IMS protocols and requires no change in the behaviour of the standard IMS entities. In order to develop a testbed for experimental verification of the design, the identification of suitable software platforms was required. This thesis presents some of the most popular platforms currently used by developers such as the Open IMS Core and OpenSER, as well as an open source, Java-based, multimedia communication platform called Mobicents. As a precursor to the development of the SCIM, a converged multimedia service is presented that describes how a video streaming application that is leveraged by a web portal was implemented for an IMS testbed using Mobicents components. The Mobicents SIP Servlets container was subsequently used to model an initial prototype of the SCIM, using a mUlti-component telephony service to illustrate the proposed service execution model. The design focuses on SIP-based services only, but should also work for other types of IMS application servers as well.
- Full Text:
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.
- Full Text:
- 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.
- Full Text: