Browsing Research Papers (Computer Science) by Issue Date
Now showing items 1-20 of 47
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Tucker, William D.; Keats, Derek (Telkom, 1998)[more][less]
Abstract: Grafting an ATM network onto an existing Ethernet network is a non-trivial exercise in network configuration. The process of mating ATM technology to an Ethernet network without tampering the underlying backbone and network configuration gives rise to a variety of networking issues including addressing, compatibility, security, efficiency, administrative effort, and scalability. Examples of actual situations serve to illustrate these issues. We have designed several scenarios to tackle the topological problems of an ATM graft. A dual IP approach works but suffers from a lack of scalability. We expect an edge routing solution, with subnetting, will be the most elegant and scalable. URI: http://hdl.handle.net/10566/448 Files in this item: 1
TuckerKeatsATM1998.pdf (612.2Kb) -
Jeffries, Michael; Tucker, William D. (Telkom, 2000)[more][less]
Abstract: Current VoIP signaling protocols are interoperable with the PSTN SS7 via H.323-to-SS7 or SIP-to-SS7 gateways. As we move toward the Next Generation Network, the PSTN falls away and we work toward carrier-grade VoIP interoperability between H.323, SIP, and other future VoIP signaling protocols. This paper present a Work in Progress to design and implement a solution based on the Internet Protocol itself. URI: http://hdl.handle.net/10566/425 Files in this item: 1
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Naidoo, Vaughn; Tucker, William D. (Telkom, 2000)[more][less]
Abstract: With QoS available on IP-dominant NGNs, Policy-based Network Management (PBNM) is an effective mechanism for managing services as opposed to actual devices. IP is ubiquitous, and any NGN must contend with legacy devices that do not support emerging PBNM protocols. This Work in Progress uses the common Internet notion of a proxy to enforce policies on legacy equipment. We use VoIP as a mechanism to test the validity of our intended solution. URI: http://hdl.handle.net/10566/449 Files in this item: 1
NaidooTuckerVoIP2000.pdf (53.16Kb) -
Naidoo, Vaughn; Tucker, William D. (Telkom, 2001)[more][less]
Abstract: Next Generation Networks use policy-based network management and QoS protocols to provide voice services on IP networks. Large numbers of older equipment still push IP packets. We present several solutions that include legacy equipment into a PBNM and QoS system. A static design uses traffic shaping at the legacy edge. A dynamic solution uses a Quasi-PEP implemented over RSVP and COPS. Preliminary test results are presented for the static solution. Collected data shows that the solution decreases packet loss on the legacy side. URI: http://hdl.handle.net/10566/519 Files in this item: 1
NaidooTuckerNextGenNetworks2001.pdf (59.43Kb) -
Glaser, Meryl; Tucker, William D. (Telkom, 2001)[more][less]
Abstract: A Teldem provides text-based telephony services to the deaf. Despite an array of text-based communications mechanisms on the web, the Teldem is the only means of synchronous telecommunication available to a deaf person. We examine a human-assisted relay that provides a bridge between the deaf and the hearing, and then propose several additional bridges. These bridges take advantage of both standard and cutting edge technologies. We present each bridge's impact on the deaf with respect to synchrony, connectivity, independence, and the Digital Divide. It is hoped that by deploying trials for each bridge, we can eventually provide the deaf with equal access. URI: http://hdl.handle.net/10566/613 Files in this item: 1
GlaserTucker-SATNAC2001.pdf (146.9Kb) -
Jeffries, Michael; Tucker, William D. (Telkom, 2001)[more][less]
Abstract: The Session Initiation Protocol and H.323 dominate the Voice over IP world. These signaling protocols are responsible for call setup and call tear down by IP telephony solutions. This project analyses and discusses the underlying H.323 and SIP interoperability issues and intends to build a scalable solution for the interoperability of these protocols. The gateway maps the call sequences between the two protocols. A test scenario establishes a barrage of call setup and tear down requests to test the scalability of any H.323/SIP interoperability solution. URI: http://hdl.handle.net/10566/465 Files in this item: 1
JeffriesTuckerSIP2001.pdf (65.32Kb) -
Penton, Jason; Tucker, William D.; Glaser, Meryl (Telkom, 2002)[more][less]
Abstract: We have developed a prototype bridge that relays text and speech between Teldem, a text telephone for the Deaf, and a standard telephone or H.323 endpoint. Telgo323 uses modified H.323 media gateways and open source Text to Speech and Speech to Text software. The approach allows for easy integration of new tools as the technologies mature. This paper presents the design of the implementation prototype, discusses Teldem tone decoding, and suggests directions for future work. The Telgo323 provides evidence that an automated relay bridge is imminently viable for the Deaf Community, and further demonstrates an attractive approach for building bridges over the Digital Divide. URI: http://hdl.handle.net/10566/612 Files in this item: 1
PentonTuckerGlaser-SATNAC2002.pdf (99.60Kb) -
Lewis, John; Tucker, William D.; Blake, Edwin H. (Telkom, 2002)[more][less]
Abstract: Users and computing equipment have varying capabilities that include the abilities to exchange text and audio, engage in high bandwidth communication, etc. As the technological options increase, e ective communication between the di erent media has be able to bridge across these options: the bridges have to take into account network quality, end-user equipment capabilities as well as user preferences and capabilities. Our research proposes a Soft- Bridge, an abstracted communications platform for the construction of applications across disparate capabilities found in various Digital Divides. We outline the architecture and the requirements that the SoftBridge has to ful ll. An approach and some initial work is described. URI: http://hdl.handle.net/10566/606 Files in this item: 1
LewisTuckerBlake-SATNAC2002.pdf (126.3Kb) -
Chetty, Marshini; Tucker, William D.; Blake, Edwin H. (Telkom, 2003)[more][less]
Abstract: There is a great disparity between those who have access to Information and Communication Technologies (ICTs) and those that do not. This phenomenon forms part of the Digital Divide. Many ICTs may be used to help overcome this divide if they are applied in a useful way, providing locally applicable content and services. Critical Action Research (CAR) is an approach used to develop such applications. CAR aims to empower people by involving them in the development process. Using CAR, this project investigates how Voice over IP (VoIP) may be applied in a productive way in an underserviced community. VoIP is an ICT used for sending voice over packet switched networks using Internet Protocol. It can be used to integrate data and voice to produce multimedia applications. In South Africa (SA), VoIP may only be provided by Telkom, the Second National Operator and the Under-Serviced Area Licensees. Using CAR and VoIP, an application is being developed to service a specific need of a particular rural community. The application will either provide a service to a small rural business or aid the provision of healthcare in rural areas. The project evaluates how well CAR integrates with a normal Software Development Lifecycle and makes policy recommendations for the use of VoIP in rural SA. URI: http://hdl.handle.net/10566/479 Files in this item: 1
ChettyTuckerBlakeDigitalDivide2003.pdf (35.78Kb) -
Adesemowo, A. Kayode; Tucker, William D. (Telkom, 2003)[more][less]
Abstract: As mobile devices and networks become more data-centric, text messaging requires an extension of co-presence capabilities for better interactive discussion between input/output handicapped handheld users and their free form desktop counterparts. Given some degree of co-presence (online presence and awareness) in text-based Instant Messaging, we hope to increase this co-presence on a handheld with fast-track feedback (FF) mechanisms. These are user-defined gestures, such as emoticons, and prioritised messages. We are building a system that facilitates gesture input within an interactive text-based chat over a wireless network running Session Initiation Protocol (SIP). The chat bridges a robust desktop environment and a small number of handhelds. This work in progress looks into the SIP Instant Messaging and Presence Leveraging Extensions as a platform to provide fast-track interactive and co-presence feedback. The aim is to rubberise a hitherto plastic and limited instant messaging conversation. We shall measure co-presence levels between FF and standard IM environments in and without desktop and handhelds by engaging two groups of users in chats session. We expect to demonstrate that there exists high co-presence notion in open (work by Sun Research Awarenex Group and AT&T Hubbubme in similar domain were in closed systems) FF text messaging open environment as we would like to show that this higher presence brings a much more enhanced interactive discourse. The envisaged results are intended to extrapolate to online aware co-presence in the up and coming smart phones on 3G packet networks. URI: http://hdl.handle.net/10566/539 Files in this item: 1
AdesemowoTuckerMobileDevices2003.pdf (180.9Kb) -
Benjamin, Anita; Tucker, William D. (Telkom, 2003)[more][less]
Abstract: We have built a hybrid voice/text web–board that utilizes floor control for handling resources such as microphone and interface events. The aim of this research is to determine the most appropriate floor control mechanism for a hybrid communication tool that allows conventional text and audio users to communicate with one another using a common interface. Research on floor control mechanisms provides many implementations for arbitration that are application-specific. Myers proposes a categorical explanation of the most widely used mechanisms for providing floor control and discusses these different dimensions with respect to a project called Pebbles. We have chosen to model our arbitration policies along these categories. The application will be implemented as a Java applet and gives users a view of both the text and audio aspects of the exchange. To facilitate the multi-modality of the system we will provide media conversion, using the Nuance system’s Java API. Our hypothesis is that well–known multi-tasking arbitration protocols such as FCFS, Round Robin, Token – based, and many more can be adapted to create a conferencing floor control policy for the interface of a hybrid communication environment so as to facilitate free–flowing multi-modal conversation. Measurements to determine which floor control implementation provides the best arbitration in terms of user interaction with the system will be calculated using RPT, ORT and usage tests based on the Kirkpatrick Model. We hope to show that users benefit more from an implicit arbitration mechanism than they do from an explicit one. URI: http://hdl.handle.net/10566/538 Files in this item: 1
BenjaminTuckerHybridVoice2003.pdf (123.3Kb) -
Tucker, William D.; Glaser, Meryl; Lewis, John (Telkom, 2003)[more][less]
Abstract: Following on several partial prototypes, we built an automated Deaf Telephony bridging application with the SoftBridge platform. The SoftBridge performs multi-modal bridging in real-time using Text-to-Speech (TTS) and Automatic Speech Recognition (ASR) utilities accessed via web services. To perform Action Research with the Deaf community in Cape Town, we invited a Deaf user (DU) to participate in a pilot study. We conducted three tests varying the input/output modalities of the hearing user (HU). The DU had a standard text in/text out Instant Messaging client. The HU client used the following specific modality combinations: Text & TTS in/Text out, TTS in/Text out and TTS in/Text & ASR out. The SoftBridge logged the conversations for subsequent analysis. The trial showed a largely successful conversation. Success factors include a) a text and computer literate DU who is familiar with research practise, b) using the system to explain the research as we conducted it and c) that the multi-modal bridging capabilities overcame the expected shortcomings of TTS and especially ASR. The lessons learned from this trial will be applied to the next trial once the necessary modifications have been implemented. URI: http://hdl.handle.net/10566/535 Files in this item: 1
TuckerDeafTelephony2003.pdf (108.8Kb) -
Lewis, John; Tucker, William D.; Blake, Edwin H. (Telkom, 2003)[more][less]
Abstract: Instant Messaging is traditionally a text only a air. However, there are instances when it would be useful to bridge to other types of media, like speech. The SoftBridge is an application framework that enables this kind of communications bridging using instant messages. Its use of protocols like the Jabber Instant Messaging Protocol and the Simple Object Access Protocol makes it simple, open and extensible. It also allows bridging to non IP communications infrastructure, like the telephone network. We describe the design and architecture of the system, protocol and extensibility mechanism. Finally we describe our experimental methodology and discuss the results of our initial experiments. URI: http://hdl.handle.net/10566/537 Files in this item: 1
LewisTuckerBlakeInstantMessaging2003.pdf (202.4Kb) -
Vuza, Xolisa; Tucker, William D. (Telkom, 2004)[more][less]
Abstract: We intend adding video messaging and conferencing to Multimodal Telemedicine Intecommunicator (MuTI), a previous system that has already been in place in the target environment. This is to allow a semi-synchronous communication to occur over the Internet Protocol. Videoconferencing can be used to communicate synchronously and video messaging in a store and forward fashion can be used to communicate asynchronously. MuTI supports store and forward of still images, voicemail and text. The system also supports real time communication by means of audio. The aim of this research is to learn how to bridge the digital divide by building applications that are useful and relevant to the users we build for. We are developing this application together with the users of the application in an iterative fashion where we build the prototypes and show the users at each cycle. The feedback that we get from the users plays an important role in building a prototype for the next cycle. The software will be instrumented to provide statistics about the system usage. We are also going to get data from the users by using questionnaires and compare this data with the statistics about software usage to see how much the system has been used and which features in the system do the users like. We are using a rural South African context in conducting this research. We hope to bring about guidelines and recommendations on how to develop applications to bridge the digital divide in a developing world context. URI: http://hdl.handle.net/10566/435 Files in this item: 1
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Sun, Tao; Tucker, William D. (Telkom, 2004)[more][less]
Abstract: We have built a SoftBridge prototype within a JAIN (Java APIs for the Integrated Network) SLEE (Service Logic Execution Environment). A SoftBridge is a semi-synchronous multimodal IP (Internet Protocol) -based communication system and the first prototype has been built for deaf telephony. This research addresses service life-cycle management for a SoftBridge with carrier grade reliability. An approach is proposed that carrier grade reliability support for a SoftBridge is provided by moving it into a JAIN SLEE. A JAIN SLEE is a general application server, which provides execution and management environment for telecommunication services. An empirical evaluation methodology is adopted to verify that JAIN SLEE enables carrier grade support for a SoftBridge. This work includes the development of functions of a SoftBridge and life-cycle management of a SoftBridge within a JAIN SLEE. Current work is busy in developing multimodal media adaptation functions of the SoftBridge prototype. System test, experiments with PBX (Private Branch Exchange)/PSTN (Public Switched Telephone Network) and evaluation of the SoftBridge prototype will be carried out in the next steps. Carrier grade reliability enables a SoftBridge to access the PSTN. A highly reliable SoftBridge could bring more new value-added services for telecom providers. Using a SoftBridge as an example, we also can learn how to go about carrier grade enhancement for IP-based communication applications in the telecoms domain. URI: http://hdl.handle.net/10566/592 Files in this item: 1
SunTucker-SATNAC2004.pdf (66.62Kb) -
Julius, Elroy P.; Tucker, William D. (Telkom, 2004)[more][less]
Abstract: This research aims to find an empirical solution for guaranteeing the delivery of synchronous and asynchronous messages within a semi-synchronous IP-based communication domain. The communication infrastructure that is needed between the Deaf and hearing communities forms the application domain within which the research is situated. SoftBridging is a framework for multi-modal bridging as well as multiuser, multi-modal conversation sessions. An implementation of this concept called SoftBridge, is a communication platform that allows a hearing and Deaf person to communicate inside a single uniform space. The system is based on an asynchronous transport mechanism that makes use of various web services to do the actual data conversions such as voice to text and text to voice. Publish-subscribe systems are an emerging paradigm for building a range of distributed applications. The architecture of publish-subscribe systems make use of Message Oriented Middleware (MOM) to guarantee reliable delivery of messages within a communication domain. We will choose one of these systems and incorporate it within the overall architecture of a SoftBridge system. We will modify the existing architecture of a SoftBridge system to reliably transport synchronous as well as asynchronous data over a synchronous established session. We will use the Session Initiation Protocol (SIP) to establish a synchronous session between various users and a SoftBridge system. The system will then be used as a basis for developing a Deaf telephony application that guarantees the delivery of messages no matter the synchrony. URI: http://hdl.handle.net/10566/463 Files in this item: 1
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Glaser, Meryl; Tucker, William D. (2004)[more][less]
Abstract: This paper presents a description of telecommunications for Deaf people in South Africa by contrasting the situation in the developed world. We explain the main motivations for providing a locally appropriate solution. Research activity began with a community-based field trial of TTYs. The recommendations of the trial motivated an innovative approach to provide synchronous and accessible relay services. Drawing from international technological developments, we designed a software solution called the SoftBridge. We employ iterative Action Research cycles to drive technological modifications to the SoftBridge and to encourage adoption by the end-user community. URI: http://hdl.handle.net/10566/593 Files in this item: 1
GlaserTucker-CVHI2004.pdf (162.9Kb) -
Adesemowo, A. Kayode; Tucker, William D. (Telkom, 2004)[more][less]
Abstract: A text only Instant Messaging (IM) built on the IETF open standard SIP/SIMPLE has been developed in line with our proposed introduction of a user-defined text Hotkey feature. These act as an on-click Affective Gesture (AG): in similitude to Face-to-Face (F2F) expressive gesture-like abilities. Given that text communication possesses expressive discourse with some presence level, we seek to show that one-click text-gesture fast-tracking enhances text communication further. For this study, we are taking a hybrid quantitative and qualitative approach. Initial Pre-trial results have shown that an AG approach is more likely to improve IM chat spontaneity/response rate. Further experimental trials are being undertaken. Mobile devices and networks are becoming more data-centric (evident in Japanese I-mode) even as mobile network voice Average Revenue Per User (ARPU) are declining, new stream of data services are required which must take cognisance of handhelds features albeit their small screen estate and input/output limitation. Given that IM is entrenched in the social space, especially among teenagers and gaining wide adoption in the business place, we believe extensions are required for IM steep uptake in the mobile world, much as SMS has gained prominence. Enhanced input mechanisms for handheld IM system are expected to increase co-presence between handheld users and their desktop-based counterparts while in a synchronous discussion. URI: http://hdl.handle.net/10566/548 Files in this item: 1
AdesemowoTuckerInstantMessaging2004.pdf (165.2Kb) -
Chetty, Marshini; Tucker, William D.; Blake, Edwin H. (SAICSIT, in assocation with ACM, 2004)[more][less]
Abstract: The digital divide between rural and urban areas within developing countries is vast. We investigate how to address this divide by introducing Information and Communication Technologies (ICTs) into remote rural areas. Our aim is to discover how to create locally relevant software applications with appropriate content for these areas. We use a user centred design approach and a modified software development lifecycle that is participatory, iterative and cyclical. This process is based on principles from Participatory Design and Action Research. This paper presents our initial experience of developing a telemedicine application for a rural village in the Eastern Cape Province of South Africa using this process. We present an overview of the methodology, describe the software application we have developed and cite several challenges we have faced. Finally we conclude that an inter-organisational and inter-disciplinary approach is needed to develop software for remote areas. URI: http://hdl.handle.net/10566/532 Files in this item: 1
ChettyTuckerBlakeICT2004.pdf (386.9Kb) -
Glaser, Meryl; Tucker, William D.; Mashao, Daniel (Telkom, 2004)[more][less]
Abstract: Following on the development of several prototypes, we have built a semi-automated Deaf Telephony prototype on the SoftBridge platform. This prototype relays text and speech between Deaf users on the Internet and hearing users on the telephone system. Previous work with a pilot trial in the laboratory revealed several opportunities for enhancement. We added a Wizard of Oz (WoOz) to replace the poorly performing automatic speech recognition functionality as well as H.323 breakout, more extensive logging and advanced call initiation functionality. In order to trial the current prototype, we initiated an Information and Communication Technology (ICT) training programme with the Deaf Community of Cape Town. Twenty Deaf users participated in the training. In addition to the training, much baseline user data was collected to give an indication of how Deaf users communicate with hearing users as well as how familiar they are with ICT devices and services. The work for the rest of this year requires us to recruit and train a WoOz operator. Subsequent trials will essentially consist of monthly cycles of prototype introduction, training, automated metric and log collection, user feedback and then feature enhancement. Linguistic analyses of the text output of the Deaf users will be analyzed. We hope to refine the SoftBridge prototype to fit the needs of the Deaf and hearing users, from both technical and social viewpoints. We expect that these iterative cycles will continue for some time and will teach us many lessons regarding multi-modal semi-synchronous IP-based communications systems. URI: http://hdl.handle.net/10566/447 Files in this item: 1
GlaserTuckerMashaoDeafTelephony2004.pdf (133.0Kb)
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