Prof. William Tucker

Permanent URI for this collection

https://hdl.handle.net/10566/1723

Position: Associate Professor Department: Computer Science Faculty: Faculty of Natural Science Qualifications: BA (Trinity University, USA), MS (Arizona State University, USA), PhD (UCT) Research publications in this repository ORICD iD 0000-0001-8636-7281 More about me: here, here and here Tel: 021 959 2516 Fax: 021 959 1274 Email: btucker@uwc.ac.za

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Now showing 1 - 20 of 89

Abstractions for designing and evaluating communication bridges for people in developing regions
(ACM, 2010) Tucker, William David; Blake, Edwin H.
This paper describes two novel abstractions that help soft- ware engineers work in developing regions to align social and technical factors when building communication systems. The abstractions extend two concepts familiar to engineers of computer networks and applications: the Open Systems Interconnect stack for design, and Quality of Service for eval- uation. The novel nature of the abstractions lies in how they help cultivate awareness of socio-cultural and technical is- sues when designing and evaluating communication bridges in the eld. Advantages of the abstractions are that they can be understood easily by software engineers, they aid communication with bene ciaries, and can therefore facili- tate collaboration. The paper makes an argument for these socially aware abstractions, describes the abstractions in de- tail, provides examples of how we used the new abstractions in the eld and then gives practical guidelines for how to use them. The simple nature of the new abstractions can help software engineers and end-users to work together to produce useful information technology based communication systems for people in developing regions.
Adapting x264 to asynchronous video telephony for the Deaf
(Telkom, 2008) Ma, Zhen Yu; Tucker, William David
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.
Affective gesture feedback Instant Messaging on handhelds
(Institute of Electrical and Electronics Engineers, Inc., 2004) Adesemowo, A. Kayode; Tucker, William David
Mobile devices and mobile networks are becoming more data-centric (evident in Japanese I-mode) even as mobile network voice Average Revenue Per User are declining, new stream of data services are required which must take cognisance of handhelds features albeit their small screen estate and input/output limitations. A text only Instant Messaging (IM) built on the Internet Engineering Task Force open standard Session Initiation Protocol (SIP) and SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) has been developed in line with our novel introduction of a user-defined text Hotkey feature. 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 results have shown that an Affective Gesture approach is more likely to improve IM chat spontaneity/response rate. 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.
Amplifying positive deviance with ICT enabling community development and interdependence
(Springer, 2017) Tucker, William David
Positive deviance is a social mechanism whereby a beneficial practice that is not considered as normal gets taken up and spread within a community. This enables a community to solve its own problems aided by mentorship and facilitation. Through two long term case studies, we have identified positive deviants and are now learning how to leverage the ICT inherent in our interventions to cultivate and amplify positive change. We find both ourselves and beneficiary communities developing through various stages of dependence, independence and interdependence. We consider the latter a strong form of development. We now look at ICT4D projects as opportunities to identify positive deviants, and to amplify positive deviance with ICT. We posit that affordable, accessible and generic ICTs offer a way to do so, and that explicitly aiming to mentor and facilitate positive deviance with such ICT offers a path toward community development and interdependence.
An analysis of voice over Internet Protocol in wireless mesh networks
(IEEE, 2014) Meeran, Mohammed Tariq; Tucker, William David
The paper focuses on analyzing the affects of wireless mesh networks with some mobile nodes on Voice over Internet Protocol service quality. Our interest is to examine this in simulation to learn how to better deploy voice services on such a network in a rural community. Wireless mesh networks' unique characteristics like multi-hop, node mobility, coverage, and medium usage cause quality of service issues for Voice over Internet Protocol implementations. This research considers three wireless mesh scenarios on 26 mesh nodes. In the first scenario all nodes are stationary. In the second, 10 nodes are mobile and 16 nodes are stationary. In a third scenario, all nodes are mobile. Nodes move at a walking speed of 1.3m per second. The analysis and results show that while node mobility can increase packet loss, delay, jitter, Voice over Internet Protocol implementations in wireless mesh networks can be successful if there is no background traffic. We recommend that Voice over Internet Protocol implementations in wireless mesh networks with some mobile nodes and background traffic be supported by quality of service standards; else it can lead to service level delivery failures.
Asynchronous video telephony for the Deaf
(Telkom, 2007) Ma, Zhen Yu; Tucker, William David
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.
Automatic voice relay with open source Kiara
(Telkom, 2009) Yi, Long; Tucker, William David
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.
Battery and data drain of over-the-top applications on low-end smartphones
(IIMC International Information Management Corporation, 2018) Om, Shree; Tucker, William David
Low-end smartphones with sub $50 price tags provide affordable device ownership to low-income populations. However, their limited capacity, when combined with the need for multimodal connectivity, raises usage concerns in rural off-grid regions. Some off-grid regions in sub-Saharan Africa provide recharge facilities using solar power and charge money for the service. Adding data bundle costs to frequent recharge costs, affordability of low-end smartphones becomes questionable in such areas. Community-controlled solar-powered wireless mesh network models with Session Initiation Protocol capability could alleviate the network usage cost conundrum and consume less power in low-end smartphones with the usage of WiFi. This paper reports on investigations that reveal usage of WiFi consumes less battery than 3G, 2G and Bluetooth. In addition, we feel that lowering recharge costs also requires battery consumption knowledge of the over-the-top applications. Using automated voice calls, this paper reports on battery and data consumption by multiple popular social media applications using one type of low-end smartphone. Data consumption was calculated with the objective of learning how to lower data bundle costs by selecting the application with least data consumption. Battery consumption due to CPU usage by the applications was also measured. Results show that WhatsApp consumes the least battery amongst instant messengers and also the least data over all apps measured. SipDroid consumes the least battery overall. Additionally, the reported experiments provide a framework for future experiments aimed at evaluating battery and data consumption by other smartphone applications.
Beyond traditional ethics when developing assistive technology for and with deaf people in developing regions
(Springer, 2015) Tucker, William David
There are limitations to traditional ethical approaches and procedures when engaged in assistive technology (AT) research for Deaf people in a developing region. Non-traditional issues arise as a consequence of employing action research, including but not limited to how informed consent is construed and obtained; empowerment of participants to become involved in co-design; awareness of unfamiliar cultural issues of participants (as opposed to subjects); and accommodating community-centred, as opposed to person-centred, nuances. This chapter describes AT research with an entity called Deaf Community of Cape Town (DCCT), a disabled people’s organisation (DPO) that works on behalf of a marginalised community of under-educated, under-employed and semi-literate Deaf people across metropolitan Cape Town. We describe how non-traditional ethical concerns arose in our experience. We reflect on how these ethical issues affect AT design, based on long-term engagement; and summarise the themes, what we have learned and how we modified our practise, and finally, offer suggestions to others working on AT in developing regions.
Bridging communications across the digital divide
(CTIT, 2004) Blake, Edwin H.; Tucker, William David
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.
Browser-based sign language communication
(Telkom, 2010) Wang, Yuan Yuan; Tucker, William David
This paper describes the design and evaluation of two browser-based video communication prototypes that support sign language communication between Deaf people. The research explores combinations of technologies, protocols and architectures with the hope to eventually provide a mobile video system that Deaf people would want to use enough to pay for. Technology products, and in particular mobile and web-based video communication systems, are designed for the majority of people in general. These are not necessarily suitable for Deaf people who have very different physiological and cultural needs. We focus on browser-based video transmission because end-users need not fiddle with application installation. Web-browsers are also common on mobile phones. This paper compares two prototypes built with Adobe Flex and the fifth version of the HyperText Markup Language, H.264 and H.263 video codecs, and PC and mobile phone implementations. The paper describes the motivation, related work, methods, prototype design and finally analyses results of user experiments conducted with Deaf users.
Browser-based video communication for deaf people
(Telkom, 2009) Wang, Yuan Yuan; Tucker, William David
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.
Call capacity for voice over Internet Protocol on wireless mesh networks
(Telkom, 2010) Zulu, Docas Dudu; Tucker, William David
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.
Cell phone notification via bluetooth for Web 2.0 applications
(Telkom, 2009) Mutemwa, Muyowa; Tucker, William David; Norman, Michael
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.
Clustered Multi-layer Multi-protocol Wireless Mesh Networks
(Telkom, 2015) Abdalla, Taha; Rey-Moreno, Carlos; Tucker, William David; Bagula, Antoine
Wireless Mesh Networks (WMNs) have emerged as an alternative option to the wired networks in areas where wired deployment is unfeasible and/or costly. They have been widely adopted in community networks as these networks are mostly built within “not for profit” projects and do not require enterprise class investment which can lead to inefficient network architectures and routing protocol designs. B.A.T.M.A.N-ADV has been designed as a simple routing protocol that adheres to lightweight equipment requirements of wireless mesh deployment in the rural areas of the developing countries. However, it is built around a flat WMN topology which is challenged with scalability, security and implementation issues; which can limit WMN growth and services expansion. This paper proposes and evaluates the performance of a new multi-layer, multi-protocol WMN architecture that addresses B.A.T.M.A.N-ADV scalability issues by borrowing from wired networks their clustering model and building around the B.A.T.M.A.N Experimental (BMX6) protocol to introduce layer2 tunnelling through a cloud of layer3 routers.
Co-designing a billing system for voice services in rural South Africa: Lessons learned
(ACM, 2014) Rey-Moreno, Carlos; Ufitamahoro, Marie Josee; Venter, Isabella; Tucker, William David
Access to information and communication technologies re- mains una ordable for many in rural areas despite recent progress in providing voice services to remote communities. The sustainability of alternative technical solutions is a chal- lenge, which can be addressed when local knowledge is taken into account during the design process. This research re- ects on the process of co-designing a billing system for voice services provided by a Community Network in rural South Africa. Several payment methods were explored with users and operators of the Community Network, focusing on the legal, nancial, technical and social feasibility - as well as constraints - of each method. Those methods that suited the community's needs were implemented and tested with stakeholders. The process revealed factors embedded in the provision of voice services by traditional voice operators in South Africa that prevent economically poor and illiterate users from fully bene ting from voice services. Solutions to these factors were explored with users and were implemented as a billing system. The system is currently being deployed in a rural South African community. Both the problems experienced and solutions proposed may inform similar ini- tiatives.
Communicating in designing an oral repository for rural African villages
(IIMC International Information Management Corporation, 2012) Reitmaier, Thomas; Bidwell, Nicola J.; Siya, Masbulele Jay; Marsden, Gary; Tucker, William David
We describe designing an asynchronous, oral repository and sharing system that we intend to suit the needs and practices of rural residents in South Africa. We aim to enable users without access to personal computers to record, store, and share information within their Xhosa community using cellphones and a tablet PC combined with their existing face-to-face oral practices. Our approach recognises that systems are more likely to be effective if the design concept and process build on existing local communication practices as well as addressing local constraints, e.g. cost. Thus, we show how the objectives for the system emerged from prolonged research locally and how we communicated insights, situated in the community, into the process of design and development in a city-based lab. We discuss how we integrated understandings about communication between situated- and localresearchers and designers and developers and note the importance of recognising and centralising subtle differences in our perception of acts of oral communication. We go on to show how the materiality of the software, the tablet form factor, and touch interaction style played into our collaborative effort in conceiving the design.
Community-based solar power revenue alternative to improve sustainability of a rural wireless mesh network
(ACM, 2013) Rey-Moreno, Carlos; Roro, Zukile; Tucker, William David; Siya, Masbulele Jay
Given the needs for a clean and easy way to maintain and secure powering wireless networks in rural areas and to gen- erate revenue to guarantee the sustainability of its intended goals, an innovative approach to leverage solar power to ad- dress both needs is presented herein. Results comprise em- powered locals trained to ensure local maintenance and ap- propriation; local usage and maintenance data; and a cost- ing of the solution and its maintenance after 10 months of operation. It is shown that the solution presented can be lo- cally maintained and could provide enough revenue for the wireless network to continue providing its intended goals.
Connecting bridges across the digital divide
(ACM, 2004) Tucker, William David
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.
Deaf telephony: community-based co-design
(Wiley, 2011) Blake, Edwin H.; Tucker, William David; Glaser, Meryl; Freudenthal, Adinda
The process of community-based co-design is one that explores various solution configurations in a multi-dimensional design space whose axes are the different dimensions of requirements and the various dimensions of designer skills and technological capabilities. The bits of this space that one can ‘see’ are determined by one's knowledge of the user needs and one's own skills. Co-design is a way of exploring that space in a way that alleviates the myopia of one's own viewpoint and bias. As one traverses this space one traces a trajectory according to one’s skills and learning and according to the users’ expressed requirements and their learning.

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