An investigation of parameter relationships in a high-speed digital multimedia environment
- Authors: Chigwamba, Nyasha
- Date: 2014
- Subjects: Multimedia communications , Digital communications , Local area networks (Computer networks) , Computer network architectures , Computer network protocols , Computer sound processing , Sound -- Recording and reproducing -- Digital techniques
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4725 , http://hdl.handle.net/10962/d1021153
- Description: With the rapid adoption of multimedia network technologies, a number of companies and standards bodies are introducing technologies that enhance user experience in networked multimedia environments. These technologies focus on device discovery, connection management, control, and monitoring. This study focused on control and monitoring. Multimedia networks make it possible for devices that are part of the same network to reside in different physical locations. These devices contain parameters that are used to control particular features, such as speaker volume, bass, amplifier gain, and video resolution. It is often necessary for changes in one parameter to affect other parameters, such as a synchronised change between volume and bass parameters, or collective control of multiple parameters. Thus, relationships are required between the parameters. In addition, some devices contain parameters, such as voltage, temperature, and audio level, that require constant monitoring to enable corrective action when thresholds are exceeded. Therefore, a mechanism for monitoring networked devices is required. This thesis proposes relationships that are essential for the proper functioning of a multimedia network and that should, therefore, be incorporated in standard form into a protocol, such that all devices can depend on them. Implementation mechanisms for these relationships were created. Parameter grouping and monitoring capabilities within mixing console implementations and existing control protocols were reviewed. A number of requirements for parameter grouping and monitoring were derived from this review. These requirements include a formal classification of relationship types, the ability to create relationships between parameters with different underlying value units, the ability to create relationships between parameters residing on different devices on a network, and the use of an event-driven mechanism for parameter monitoring. These requirements were the criteria used to govern the implementation mechanisms that were created as part of this study. Parameter grouping and monitoring mechanisms were implemented for the XFN protocol. The mechanisms implemented fulfil the requirements derived from the review of capabilities of mixing consoles and existing control protocols. The formal classification of relationship types was implemented within XFN parameters using lists that keep track of the relationships between each XFN parameter and other XFN parameters that reside on the same device or on other devices on the network. A common value unit, known as the global unit, was defined for use as the value format within value update messages between XFN parameters that have relationships. Mapping tables were used to translate the global unit values to application-specific (universal) units, such as decibels (dB). A mechanism for bulk parameter retrieval within the XFN protocol was augmented to produce an event-driven mechanism for parameter monitoring. These implementation mechanisms were applied to an XFN-protocol-compliant graphical control application to demonstrate their usage within an end user context. At the time of this study, the XFN protocol was undergoing standardisation within the Audio Engineering Society. The AES-64 standard has now been approved. Most of the implementation mechanisms resulting from this study have been incorporated into this standard.
- Full Text:
- Date Issued: 2014
- Authors: Chigwamba, Nyasha
- Date: 2014
- Subjects: Multimedia communications , Digital communications , Local area networks (Computer networks) , Computer network architectures , Computer network protocols , Computer sound processing , Sound -- Recording and reproducing -- Digital techniques
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4725 , http://hdl.handle.net/10962/d1021153
- Description: With the rapid adoption of multimedia network technologies, a number of companies and standards bodies are introducing technologies that enhance user experience in networked multimedia environments. These technologies focus on device discovery, connection management, control, and monitoring. This study focused on control and monitoring. Multimedia networks make it possible for devices that are part of the same network to reside in different physical locations. These devices contain parameters that are used to control particular features, such as speaker volume, bass, amplifier gain, and video resolution. It is often necessary for changes in one parameter to affect other parameters, such as a synchronised change between volume and bass parameters, or collective control of multiple parameters. Thus, relationships are required between the parameters. In addition, some devices contain parameters, such as voltage, temperature, and audio level, that require constant monitoring to enable corrective action when thresholds are exceeded. Therefore, a mechanism for monitoring networked devices is required. This thesis proposes relationships that are essential for the proper functioning of a multimedia network and that should, therefore, be incorporated in standard form into a protocol, such that all devices can depend on them. Implementation mechanisms for these relationships were created. Parameter grouping and monitoring capabilities within mixing console implementations and existing control protocols were reviewed. A number of requirements for parameter grouping and monitoring were derived from this review. These requirements include a formal classification of relationship types, the ability to create relationships between parameters with different underlying value units, the ability to create relationships between parameters residing on different devices on a network, and the use of an event-driven mechanism for parameter monitoring. These requirements were the criteria used to govern the implementation mechanisms that were created as part of this study. Parameter grouping and monitoring mechanisms were implemented for the XFN protocol. The mechanisms implemented fulfil the requirements derived from the review of capabilities of mixing consoles and existing control protocols. The formal classification of relationship types was implemented within XFN parameters using lists that keep track of the relationships between each XFN parameter and other XFN parameters that reside on the same device or on other devices on the network. A common value unit, known as the global unit, was defined for use as the value format within value update messages between XFN parameters that have relationships. Mapping tables were used to translate the global unit values to application-specific (universal) units, such as decibels (dB). A mechanism for bulk parameter retrieval within the XFN protocol was augmented to produce an event-driven mechanism for parameter monitoring. These implementation mechanisms were applied to an XFN-protocol-compliant graphical control application to demonstrate their usage within an end user context. At the time of this study, the XFN protocol was undergoing standardisation within the Audio Engineering Society. The AES-64 standard has now been approved. Most of the implementation mechanisms resulting from this study have been incorporated into this standard.
- Full Text:
- Date Issued: 2014
Developing SOA wrappers for communication purposes in rural areas
- Authors: Samalenge, Jimmy
- Date: 2010
- Subjects: Computer network architectures , Computer architecture , Computer software -- Specifications , Rural development projects -- South Africa -- Eastern Cape , Web services , System design , Technological innovations -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11386 , http://hdl.handle.net/10353/320 , Computer network architectures , Computer architecture , Computer software -- Specifications , Rural development projects -- South Africa -- Eastern Cape , Web services , System design , Technological innovations -- South Africa -- Eastern Cape
- Description: The introduction of Web Services as a platform upon which applications can communicate has contributed a great deal towards the expansion of World Wide Web technologies. The Internet and computing technologies have been some of the factors that have contributed to the socio-economic improvement of urban and industrial areas. This research focuses on the application of Service-Oriented Architecture (SOA) and Web Services technologies in Information and Communication Technologies for Development (ICT4D) contexts. SOA is a style used to design distributed systems, and Web Services are some of the common realizations of the SOA. Web Services allow the exchange of data between two or more machines in a simple and standardized manner over the network. This has resulted in the augmentation of ways in which individuals in a society and in the world communicate. This research aims to develop a SOA-based system with services that are implemented as Web Services. The system is intended to support communication activities of Dwesa community members. The communication methods identified as the most commonly used in the Dwesa community are Short Message Services (SMSs) and voice calls. In this research we have identified further methods (i.e. Multimedia Message Service, Electronic mail and Instant Messaging) to augment communication activities in Dwesa. The developed system, therefore, exposes SMS Web Service, MMS Web Service, Email Web Service and IM Web Service that are consumed in machine-to-machine, machine-to-person and person-to-person types of communication. We have also implemented a one-stop communication shop, through a web portal which provides interfaces to the different communication modules. Elaborate functional and usability testing have also been undertaken to establish the viability and end-user acceptance of the system respectively. This research has provided the initial validation of the effectiveness of the SOA-based system in ICT4D contexts
- Full Text:
- Date Issued: 2010
- Authors: Samalenge, Jimmy
- Date: 2010
- Subjects: Computer network architectures , Computer architecture , Computer software -- Specifications , Rural development projects -- South Africa -- Eastern Cape , Web services , System design , Technological innovations -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11386 , http://hdl.handle.net/10353/320 , Computer network architectures , Computer architecture , Computer software -- Specifications , Rural development projects -- South Africa -- Eastern Cape , Web services , System design , Technological innovations -- South Africa -- Eastern Cape
- Description: The introduction of Web Services as a platform upon which applications can communicate has contributed a great deal towards the expansion of World Wide Web technologies. The Internet and computing technologies have been some of the factors that have contributed to the socio-economic improvement of urban and industrial areas. This research focuses on the application of Service-Oriented Architecture (SOA) and Web Services technologies in Information and Communication Technologies for Development (ICT4D) contexts. SOA is a style used to design distributed systems, and Web Services are some of the common realizations of the SOA. Web Services allow the exchange of data between two or more machines in a simple and standardized manner over the network. This has resulted in the augmentation of ways in which individuals in a society and in the world communicate. This research aims to develop a SOA-based system with services that are implemented as Web Services. The system is intended to support communication activities of Dwesa community members. The communication methods identified as the most commonly used in the Dwesa community are Short Message Services (SMSs) and voice calls. In this research we have identified further methods (i.e. Multimedia Message Service, Electronic mail and Instant Messaging) to augment communication activities in Dwesa. The developed system, therefore, exposes SMS Web Service, MMS Web Service, Email Web Service and IM Web Service that are consumed in machine-to-machine, machine-to-person and person-to-person types of communication. We have also implemented a one-stop communication shop, through a web portal which provides interfaces to the different communication modules. Elaborate functional and usability testing have also been undertaken to establish the viability and end-user acceptance of the system respectively. This research has provided the initial validation of the effectiveness of the SOA-based system in ICT4D contexts
- Full Text:
- Date Issued: 2010
An investigation into the hardware abstraction layer of the plural node architecture for IEEE 1394 audio devices
- Authors: Chigwamba, Nyasha
- Date: 2009
- Subjects: IEEE 1394 (Standard) , Digital communications , Computer sound processing , Local area networks (Computer networks) , Computer network architectures , Sound -- Recording and reproducing -- Digital techniques
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4598 , http://hdl.handle.net/10962/d1004841 , IEEE 1394 (Standard) , Digital communications , Computer sound processing , Local area networks (Computer networks) , Computer network architectures , Sound -- Recording and reproducing -- Digital techniques
- Description: Digital audio network technologies are becoming more prevalent in audio related environments. Yamaha Corporation has created a digital audio network solution, named mLAN (music Local Area Network), that uses IEEE 1394 as its underlying network technology. IEEE 1394 is a digital network technology that is specifically designed for real-time multimedia data transmission. The second generation of mLAN is based on the Plural Node Architecture, where the control of audio and MIDI routings between IEEE 1394 devices is split between two node types, namely an Enabler and a Transporter. The Transporter typically resides in an IEEE 1394 device and is solely responsible for transmission and reception of audio or MIDI data. The Enabler typically resides in a workstation and exposes an abstract representation of audio or MIDI plugs on each Transporter to routing control applications. The Enabler is responsible for configuring audio and MIDI routings between plugs on different Transporters. A Hardware Abstraction Layer (HAL) within the Enabler allows it to uniformly communicate with Transporters that are created by various vendors. A plug-in mechanism is used to provide this capability. When vendors create Transporters, they also create device-specific plug-ins for the Enabler. These plug-ins are created against a Transporter HAL Application Programming Interface (API) that defines methods to access the capabilities of Transporters. An Open Generic Transporter (OGT) guideline document which models all the capabilities of Transporters has been produced. These guidelines make it possible for manufacturers to create Transporters that make use of a common plug-in, although based on different hardware architectures. The introduction of the OGT concept has revealed additional Transporter capabilities that are not incorporated in the existing Transporter HAL API. This has led to the underutilisation of OGT capabilities. The main goals of this investigation have been to improve the Enabler’s plug-in mechanism, and to incorporate the additional capabilities that have been revealed by the OGT into the Transporter HAL API. We propose a new plug-in mechanism, and a new Transporter HAL API that fully utilises both the additional capabilities revealed by the OGT and the capabilities of existing Transporters.
- Full Text:
- Date Issued: 2009
- Authors: Chigwamba, Nyasha
- Date: 2009
- Subjects: IEEE 1394 (Standard) , Digital communications , Computer sound processing , Local area networks (Computer networks) , Computer network architectures , Sound -- Recording and reproducing -- Digital techniques
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4598 , http://hdl.handle.net/10962/d1004841 , IEEE 1394 (Standard) , Digital communications , Computer sound processing , Local area networks (Computer networks) , Computer network architectures , Sound -- Recording and reproducing -- Digital techniques
- Description: Digital audio network technologies are becoming more prevalent in audio related environments. Yamaha Corporation has created a digital audio network solution, named mLAN (music Local Area Network), that uses IEEE 1394 as its underlying network technology. IEEE 1394 is a digital network technology that is specifically designed for real-time multimedia data transmission. The second generation of mLAN is based on the Plural Node Architecture, where the control of audio and MIDI routings between IEEE 1394 devices is split between two node types, namely an Enabler and a Transporter. The Transporter typically resides in an IEEE 1394 device and is solely responsible for transmission and reception of audio or MIDI data. The Enabler typically resides in a workstation and exposes an abstract representation of audio or MIDI plugs on each Transporter to routing control applications. The Enabler is responsible for configuring audio and MIDI routings between plugs on different Transporters. A Hardware Abstraction Layer (HAL) within the Enabler allows it to uniformly communicate with Transporters that are created by various vendors. A plug-in mechanism is used to provide this capability. When vendors create Transporters, they also create device-specific plug-ins for the Enabler. These plug-ins are created against a Transporter HAL Application Programming Interface (API) that defines methods to access the capabilities of Transporters. An Open Generic Transporter (OGT) guideline document which models all the capabilities of Transporters has been produced. These guidelines make it possible for manufacturers to create Transporters that make use of a common plug-in, although based on different hardware architectures. The introduction of the OGT concept has revealed additional Transporter capabilities that are not incorporated in the existing Transporter HAL API. This has led to the underutilisation of OGT capabilities. The main goals of this investigation have been to improve the Enabler’s plug-in mechanism, and to incorporate the additional capabilities that have been revealed by the OGT into the Transporter HAL API. We propose a new plug-in mechanism, and a new Transporter HAL API that fully utilises both the additional capabilities revealed by the OGT and the capabilities of existing Transporters.
- Full Text:
- Date Issued: 2009
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:
- Date Issued: 2008
- 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:
- Date Issued: 2008
Investigating the viability of a framework for small scale, easily deployable and extensible hotspot management systems
- Authors: Thinyane, Mamello P
- Date: 2006
- Subjects: Local area networks (Computer networks) , Computer networks -- Management , Computer network architectures , Computer network protocols , Wireless communication systems , XML (Document markup language)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4638 , http://hdl.handle.net/10962/d1006553
- Description: The proliferation of PALs (Public Access Locations) is fuelling the development of new standards, protocols, services, and applications for WLANs (Wireless Local Area Networks). PALs are set up at public locations to meet continually changing, multiservice, multi-protocol user requirements. This research investigates the essential infrastructural requirements that will enable further proliferation of PALs, and consequently facilitate ubiquitous computing. Based on these requirements, an extensible architectural framework for PAL management systems that inherently facilitates the provisioning of multiple services and multiple protocols on PALs is derived. The ensuing framework, which is called Xobogel, is based on the microkernel architectural pattern, and the IPDR (Internet Protocol Data Record) specification. Xobogel takes into consideration and supports the implementation of diverse business models for PALs, in respect of distinct environmental factors. It also facilitates next-generation network service usage accounting through a simple, flexible, and extensible XML based usage record. The framework is subsequently validated for service element extensibility and simplicity through the design, implementation, and experimental deployment of SEHS (Small Extensible Hotspot System), a system based on the framework. The robustness and scalability of the framework is observed to be sufficient for SMME deployment, withstanding the stress testing experiments performed on SEHS. The range of service element and charging modules implemented confirm an acceptable level of flexibility and extensibility within the framework.
- Full Text:
- Date Issued: 2006
- Authors: Thinyane, Mamello P
- Date: 2006
- Subjects: Local area networks (Computer networks) , Computer networks -- Management , Computer network architectures , Computer network protocols , Wireless communication systems , XML (Document markup language)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4638 , http://hdl.handle.net/10962/d1006553
- Description: The proliferation of PALs (Public Access Locations) is fuelling the development of new standards, protocols, services, and applications for WLANs (Wireless Local Area Networks). PALs are set up at public locations to meet continually changing, multiservice, multi-protocol user requirements. This research investigates the essential infrastructural requirements that will enable further proliferation of PALs, and consequently facilitate ubiquitous computing. Based on these requirements, an extensible architectural framework for PAL management systems that inherently facilitates the provisioning of multiple services and multiple protocols on PALs is derived. The ensuing framework, which is called Xobogel, is based on the microkernel architectural pattern, and the IPDR (Internet Protocol Data Record) specification. Xobogel takes into consideration and supports the implementation of diverse business models for PALs, in respect of distinct environmental factors. It also facilitates next-generation network service usage accounting through a simple, flexible, and extensible XML based usage record. The framework is subsequently validated for service element extensibility and simplicity through the design, implementation, and experimental deployment of SEHS (Small Extensible Hotspot System), a system based on the framework. The robustness and scalability of the framework is observed to be sufficient for SMME deployment, withstanding the stress testing experiments performed on SEHS. The range of service element and charging modules implemented confirm an acceptable level of flexibility and extensibility within the framework.
- Full Text:
- Date Issued: 2006
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