Research Articles (Computer Science)

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https://hdl.handle.net/10566/52

The research papers in this collection represent the work of several projects.

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3D forensic crime scene reconstruction involving immersive technology: A systematic literature review
(Institute of Electrical and Electronics Engineers, 2022) Maneli, Mfundo A.; Isafiade, Omowunmi E.
Recreation of 3D crime scenes is critical for law enforcement in the investigation of serious crimes for criminal justice responses. This work presents a premier systematic literature review (SLR) that offers a structured, methodical, and rigorous approach to understanding the trend of research in 3D crime scene reconstruction as well as tools, technologies, methods, and techniques employed thereof in the last 17 years. Major credible scholarly database sources, Scopus, and Google Scholar, which index journals and conferences that are promoted by entities such as IEEE, ACM, Elsevier, and SpringerLink were explored as data sources. Of the initial 17, 912 papers that resulted from the first search string, 258 were found to be relevant to our research questions after implementing the inclusion and exclusion criteria.
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.
Africa 3: A continental network model to enable the African fourth industrial revolution
(IEEE, 2020) Ajayi, Olasupo O; Bagula, Antoine B.; Maluleke, Hloniphani C.
It is widely recognised that collaboration can help fast-track the development of countries in Africa. Leveraging on the fourth industrial revolution, Africa can achieve accelerated development in health care services, educational systems and socio-economic infrastructures. While a number of conceptual frameworks have been proposed for the African continent, many have discounted the Cloud infrastructure used for data storage and processing as well as the underlying network infrastructure upon which such frameworks would be built. This work therefore presents a continental network model for interconnecting nations in Africa through its data centres. The proposed model is based on a multilayer network engineering approach, which first groups African countries into clusters of data centers using a hybrid combination of clustering techniques; then utilizes Ant Colony Optimisation with Stench Pheromone, that is modified to support variable evaporation rates, to find ideal network path(s) across the clusters and the continent as a whole. The proposed model takes into consideration the geo-spatial location, population sizes, data centre counts and intercontinental submarine cable landings of each African country, when clustering and routing. For bench-marking purposes, the path selection algorithm was tested on both the obtained clusters and African Union’s regional clusters.
Agent-based context-aware healthcare information retrieval using DROPT approach
(International Science Press, 2012) Agbele, Kehinde K.; Adesina, Ademola Olusola; Daniel, Ekong; Seluwa, Dele
As the volume of information available on the Web information systems is growing continuously, browsing this content becomes a tedious task given the presentation of data that does meet user's aims and needs. In this paper, to satisfy user needs, an agent-based paradigm is an appropriate solution which gives outputs suitable to the user in the form of highly ranked documents. Conversely, patient care and a health condition commonly require collaboration between healthcare providers. The emergence of agent's technology motivates radical changes of how information is obtained. This paper addresses this problem by proposing a novel DROPT (Document Ranking OPTimization) measure for information retrieval results to validate the effectiveness of the information management tasks. We propose information retrieval system architecture, which main components are context aware agent’s technology to meet users' information needs.
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.
ANCAEE: A novel clustering algorithm for energy efficiency in wireless sensor networks
(Scientific Research Publishing, 2011) Abidoye, Ademola P.; Azeez, Nureni A.; Adesina, Ademola Olusola; Agbele, Kehinde K.
One of the major constraints of wireless sensor networks is limited energy available to sensor nodes because of the small size of the batteries they use as source of power. Clustering is one of the routing techniques that have been using to minimize sensor nodes’ energy consumption during operation. In this paper, A Novel Clustering Algorithm for Energy Efficiency in Wireless Sensor Networks (ANCAEE) has been proposed. The algorithm achieves good performance in terms of minimizing energy consumption during data transmis-sion and energy consumptions are distributed uniformly among all nodes. ANCAEE uses a new method of clusters formation and election of cluster heads. The algorithm ensures that a node transmits its data to the cluster head with a single hop transmission and cluster heads forward their data to the base station with multi-hop transmissions. Simulation results show that our approach consumes less energy and effectively extends network utilization.
Article comparing three countries’ higher education students’ cyber related perceptions and behaviours during COVID-19
(MPDI, 2021) Tick, Andrea; Cranfield, Desireé J.; Renaud, Karen V.
: In 2020, a global pandemic led to lockdowns, and subsequent social and business restrictions. These required overnight implementation of emergency measures to permit continued functioning of vital industries. Digital technologies and platforms made this switch feasible, but it also introduced several cyber related vulnerabilities, which students might not have known how to mitigate. For this study, the Global Cyber Security Index and the Cyber Risk literacy and education index were used to provide a cyber security context for each country. This research project—an international, cross-university, comparative, quantitative project—aimed to explore the risk attitudes and concerns, as well as protective behaviours adopted by, students at a South African, a Welsh and a Hungarian University, during the pandemic. This study’s findings align with the relative rankings of the Oliver Wyman Risk Literacy and Education Index for the countries in which the universities reside. This study revealed significant differences between the student behaviours of students within these universities.
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.
Basic statistical estimation outperforms machine learning in monthly prediction of seasonal climatic parameters
(MPDI, 2021) Hussein, Eslam A.; Ghaziasgar, Mehrdad; Thron, Christopher
Machine learning (ML) has been utilized to predict climatic parameters, and many successes have been reported in the literature. In this paper, we scrutinize the effectiveness of five widely used ML algorithms in the monthly prediction of seasonal climatic parameters using monthly image data. Specifically, we quantify the predictive performance of these algorithms applied to five climatic parameters using various combinations of features. We compare the predictive accuracy of the resulting trained ML models to that of basic statistical estimators that are computed directly from the training data. Our results show that ML never significantly outperforms the statistical baseline, and underperforms for most feature sets. Unlike previous similar studies, we provide error bars for the relative performance of different predictors based on jackknife estimates applied to differences in predictive error magnitudes. We also show that the practice of shuffling data sequences which was employed in some previous references leads to data leakage, resulting in over-estimated performance. Ultimately, the paper demonstrates the importance of using well-grounded statistical techniques when producing and analyzing the results of ML predictive models.
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.
A bridge over the computer science graduate skill gap
(2013) Blignaut, Renette; Venter, Isabella M.; Renaud, Karen
Universities are increasingly required to respond to the ever evolving needs of an ever more sophisticated and globalised workplace, which requires well-rounded workers with more than mere technical knowledge. Employers expect their prospective employees to already have acquired a range of professional and personal skills. Universities face a challenge in helping students to develop these skills and it is debatable whether this can be achieved within the university environment. What is needed is a way for students to interact with the outside world as part of their undergraduate programme in a situated learning environment. This paper reports on a computer science assignment specifically designed to develop professional and personal as well as discipline-specific skills. The results suggest that situated learning assignments are indeed able to enhance the development of precisely those soft skills which are so valued by employers.
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.

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