Browsing Research Papers (Computer Science) by Title
Now showing items 1-20 of 47
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Ma, Zhen Yu; Tucker, William D. (Telkom, 2008)[more][less]
Abstract: Deaf people want to communicate remotely with sign language. Sign language requires sufficient video quality to be intelligible. Internet-based real-time video tools do not provide that quality. Our approach is to use asynchronous transmission to maintain video quality. Unfortunately, this entails a corresponding increase in latency. To reduce latency as much as possible, we sought to adapt a synchronous video codec to an asynchronous video application. First we compared several video codecs with subjective and objective metrics. This paper describes the process by which we chose x264 and integrated it into a Deaf telephony video application, and experimented to configure x264 optimally for the asynchronous environment. URI: http://hdl.handle.net/10566/511 Files in this item: 1
MaTuckerDeafVideoTelephony2008.pdf (348.1Kb) -
Ma, Zhen Yu; Tucker, William D. (Telkom, 2007)[more][less]
Abstract: The South African Deaf community has very limited telephony options. They prefer to communicate in sign language, a visual medium. Realtime video over Internet Protocol is a promising option, but in reality, the quality is often not enough for the Deaf to be able to understand each other’s sign language. Furthermore, these applications were not design specifically for the Deaf. This paper introduces an asynchronous video chat system to provide better quality video at the expense of increased latency. It determined a codec/transmission protocol combination in the laboratory environment and tested it out with actual Deaf users. This paper will address the results based on comparison between different codecs, transmission protocol on asynchronous video communication for the Deaf. URI: http://hdl.handle.net/10566/486 Files in this item: 1
MaTuckerDeaf2007.pdf (875.1Kb) -
Yi, Long; Tucker, William D. (Telkom, 2009)[more][less]
Abstract: One way for Deaf people to communicate with hearing people over the telephone is to use a voice relay. The service is often provided with a human relay operator that relays text into voice, and vice versa, on behalf of the Deaf and hearing users. In developed countries, voice relay is frequently subsidised by governments or service providers. There is no such service in South Africa. We have built several automatic voice relay systems for a disadvantaged Deaf community in Cape Town. This paper describes how we augmented a general-purpose communication system for voice relay. Kiara is a fully open source Instant Messaging, voice and video over Internet Protocol communication system based on the Session Initiation Protocol. We integrated automatic speech recognition and text-to-speech technologies into Kiara to provide real-time automatic voice relay for relayed communication. As it stands, Kiara can also be used for standard voice and video relay with a human operator. URI: http://hdl.handle.net/10566/619 Files in this item: 1
YiTucker-SATNAC2009.pdf (257.6Kb) -
Blake, Edwin H.; Tucker, William D. (CTIT, 2004)[more][less]
Abstract: Connecting people across the Digital Divide is as much a social effort as a technological one. We are developing a community-centered approach to learn how interaction techniques can compensate for poor communication across the Digital Divide. We have incorporated the lessons learnt regarding Social Intelligence Design in an (abstract) device called the SoftBridge. The device allows information to flow from endpoints through adapters (getting converted if necessary), and out to destination endpoints. Field trials are underway with two communities in South Africa, disadvantaged deaf users and an isolated rural community. First lessons learned show that we have to design user interfaces that allow users to understand and cope with delay (latency) as a necessary consequence of our approach. URI: http://hdl.handle.net/10566/617 Files in this item: 1
BlakeTucker-SID2004.pdf (158.2Kb) -
Wang, Yuan Yuan; Tucker, William D. (Telkom, 2009)[more][less]
Abstract: This paper describes work in progress to to provide browser-based sign language communication for Deaf users. The paper introduces the communication requirements for a disadvantaged Deaf community in Cape Town, describes related work of generic open source browser-based video and video systems targeted specifically to Deaf users. We posit an experimental design to test if Adobe Flash can help provide an acceptable video system for Deaf users. We wish to learn if the transport and video quality of browser-based Adobe Flash video can provide an effective platform for sign language communication. URI: http://hdl.handle.net/10566/622 Files in this item: 1
WangTucker-SATNAC2009.pdf (141.2Kb) -
Zulu, Docas Dudu; Tucker, William D. (Telkom, 2010)[more][less]
Abstract: This paper describes work in progress on call capacity optimization for voice over Internet Protocol on wireless mesh networks. In a developing country such as South Africa, evidence has shown that rural inhabitants find it difficult to afford the voice services offered by cellular networks. Voice over Internet Protocol is known for its affordability relative to cellular voice services, therefore deploying such services for rural communities will not only benefit rural inhabitants but also offer economic advantages to service providers. We are interested in the provision of voice services with rural wireless mesh networks. Unfortunately voice on mesh networks can experience packet loss and delays that cause reduction in voice quality. Transmission of small voice packets over wireless mesh networks imposes high overhead that leads to a tremendous decrease in call capacity. Therefore, we aim to study the performance of voice over 802.11 wireless mesh networks and evaluate packet aggregation mechanisms that merge small voice packets into a single large packet, in order to preserve voice quality with more calls. We will implement and evaluate packet aggregations mechanisms on a 'mesh potato' network with iterative cycles of laboratory experiments using a network simulator to collect data for performance evaluation. URI: http://hdl.handle.net/10566/618 Files in this item: 1
ZuluTucker-SATNAC2010.pdf (138.4Kb) -
Mutemwa, Muyowa; Tucker, William D.; Norman, Michael (Telkom, 2009)[more][less]
Abstract: This paper discusses how an Instant Messaging application on a computer can use Bluetooth in order to provide vibration notification on a mobile phone. The initial motivation was to aid Deaf1 office workers to know when events happened on the computer on their desks. Deaf people with access to modern technology have become accustomed to using Instant Messaging, email and video conferencing. However, most of these applications are designed for hearing users and often use audible notification. Cell phone vibration offers a way to convey similar notifications because many Deaf users have a cell phone. The use of SMS has also become widespread among Deaf users because they cannot hear or speak, even though they might be somewhat text illiterate. Vibration notification in addition to aural notification is common on most cell phones and Deaf users can use the former. This paper describes a Bluetooth notification system to notify a Deaf user with vibration on a cell phone whenever a new Instant Message is received on a given computer. A design goal was to provide an application programming interface to the notification system so that it can be used with any form of Web 2.0 desktop communication tool. URI: http://hdl.handle.net/10566/530 Files in this item: 1
MutemwaNormanTuckerBluetooth2009.pdf (343.6Kb) -
Tucker, William D. (ACM, 2004)[more][less]
Abstract: Connecting people across the Digital Divide is as much a social effort as a technological one. We are developing a community-centered approach to learn how interaction techniques can compensate for poor communication across the Digital Divide. Preliminary trials have yielded interfaces that deal with poor quality by adapting Instant Messaging techniques for multiple modalities, providing improved semi-synchronous communication. Lessons learned suggest new ways to design user interfaces specifically for the developing world. URI: http://hdl.handle.net/10566/591 Files in this item: 1
Tucker-CHI2004.pdf (81.56Kb) -
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) -
Adesina, Ademola O.; Agbele, Kehinde K.; Februarie, Ronald; Abidoye, Ademola P.; Nyongesa, Henry O. (Academy of Science of South Africa, 2011)[more][less]
Abstract: The sensitivity of health-care information and its accessibility via the Internet and mobile technology systems is a cause for concern in these modern times. The privacy, integrity and confidentiality of a patient’s data are key factors to be considered in the transmission of medical information for use by authorised health-care personnel. Mobile communication has enabled medical consultancy, treatment, drug administration and the provision of laboratory results to take place outside the hospital. With the implementation of electronic patient records and the Internet and Intranets, medical information sharing amongst relevant health-care providers was made possible. But the vital issue in this method of information sharing is security: the patient’s privacy, as well as the confidentiality and integrity of the health-care information system, should not be compromised. We examine various ways of ensuring the security and privacy of a patient’s electronic medical information in order to ensure the integrity and confidentiality of the information. URI: http://hdl.handle.net/10566/279 Files in this item: 1
AdesinaSecurity2011.pdf (453.4Kb) -
Hersh, Marion A.; Tucker, William D. (Elsevier, 2005)[more][less]
Abstract: There are a number of pressures on researchers in academia and industry to behave unethically or compromise their ethical standards, for instance in order to obtain funding or publish frequently. In this paper a case study of Deaf telephony is used to discuss the pressures to unethical behaviour in terms of withholding information or misleading participants that can result from mono-disciplinary orthodoxies. The Deaf telephony system attempts to automate multiple aspects of relayed communication between Deaf and hearing users. The study is analysed in terms of consequentialist and deontological ethics, as well as multi-loop action learning. Discussion of a number of examples of bad practice is used to indicate both the compatibility of ethical behaviour and good scientific method and that ethical behaviour is a pre-requisite for obtaining meaningful results. URI: http://hdl.handle.net/10566/466 Files in this item: 1
HershTuckerUnethicalBehaviour2005.pdf (86.66Kb) -
Chitedze, Zimani; Tucker, William D. (Telkom, 2012)[more][less]
Abstract: This paper shows that mobility management protocols for infrastructure Internet may be used in a wireless mesh network environment. Mesh topology tends to be an unplanned graph and routes change dynamically and in this research Mobile IPv6 and Fast Handover for Hierarchical Mobile IPv6 are successfully implemented in a wireless mesh network environment. Horizontal handover simulation with ns2 involved Mobile IPv6 and Fast Handover for Hierarchical Mobile IPv6 applied to wireless mesh networks. Mobile IPv6 was used as a baseline to compare the performance of the two protocols. The results show that in mesh networks, Fast Handover for Hierarchical Mobile IPv6‘s performance is superior to Mobile IPv6. Fast Handover for Hierarchical Mobile IPv6 generates more throughput and less delay than Mobile IPv6. Furthermore, Fast Handover for Hierarchical Mobile IPv6 drops fewer data packets than Mobile IPv6. Even though MIPv6 and its extensions are for infrastructure networks, they can be used effectively in mesh networks. URI: http://hdl.handle.net/10566/424 Files in this item: 1
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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.; 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) -
Julius, Elroy P.; Tucker, William D. (Telkom, 2005)[more][less]
Abstract: This paper presents an empirical solution for guaranteeing the delivery of synchronous and asynchronous messages within a semi-synchronous IPbased communication domain. The communication infrastructure that is needed between 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 multi-user, multi-modal conversation sessions. An implementation of this concept called SoftBridge for Instant Messaging Bridging Application (SIMBA), is a communication platform that allows a hearing and Deaf person to communicate inside a single uniform space. The system 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 publishsubscribe systems make use of Message Oriented Middleware (MOM) to guarantee reliable delivery of messages within a communication domain. We have incorporated a publish-subscribe system within the overall architecture of SIMBA. We have thus modified the existing architecture of SIMBA to reliably transport semi-synchronous data over a synchronous established session. We have chosen to use the Session Initiation Protocol (SIP) for the establishment of a synchronous session between various users and SIMBA. The system is currently being 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/10566/509 Files in this item: 1
JuliusTuckerSoftBridging2005.pdf (589.9Kb) -
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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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) -
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) -
Adesemowo, A. Kayode; Tucker, William D. (SAICSIT in association with ACM, 2005)[more][less]
Abstract: Text communication can be perceived as lacking in chat spontaneity, or plastic, due to medium limitations during interaction. A form of text messaging, Instant Messaging (IM), is now on the uptake, even on mobile handhelds. This paper presents results of using affective gesture to rubberise IM chat in order to improve synchronous communication spontaneity. The experimental design makes use of a text-only IM tool, running on handhelds, built with the Session Initiation Protocol (SIP) and the SIP Instant Messaging and Presence Leveraging Extensions (SIMPLE). The tool was developed with a novel user-defined hotkey – a one-click context menu that fast-tracks the creation and transmission of text-gestures and emoticons. A hybrid quantitative and qualitative approach was taken in order to enable data triangulation. Data collected from user trials affirms that the affective gesture hotkey facility improves chat responsiveness, thus enhancing chat spontaneity. URI: http://hdl.handle.net/10566/464 Files in this item: 1
AdesemowoTuckerInstantMessaging2005.pdf (364.4Kb) -
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)
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