Conference Publications

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The 2020 WMO symposium on climatological, meteorological and environmental factors in the COVID-19 pandemic: A special issue from symposium presentations
(2021-06) Sweijd, Neville; Zaitchik, BF
The COVID-19 pandemic has become one of the great historical events of the modern era, presenting a generational challenge to the world. Questions about the role of weather on SARS-CoV-2 transmission led to the gathering of scientists at an online event, the “International Virtual Symposium on Climatological, Meteorological and Environmental factors in the COVID-19 pandemic,” convened on 4–6 August 2020 under the auspices of the World Meteorological Organization. This collection of papers arise from the Symposium.
A framework for resource overprovisioning with machine learning to maximise revenue from 5G Core network slices
(2025-12) Mamushiane, L; Mwangama, J; Lysko, Albert A; Kobo, Hlabishi I
Network slicing has emerged as a key enabler for delivering diverse services in 5G and beyond networks, where each slice must be provisioned with sufficient resources while maintaining operator profitability. Traditional admission control strategies are often conservative, leading to underutilization, while aggressive allocation risks violating service-level agreements (SLAs). This paper proposes a machine learning-based forecasting and admission control framework that leverages overprovisioning to balance utilization, revenue, and reliability. The framework combines CNN-LSTM forecasting for predicting slice resource demand with a policy that admits slice requests based on forecasted aggregate utilization scaled by an overprovisioning factor. To evaluate the approach, we use over 500 VM workload traces from the Materna dataset, grouping VMs into slices of ten. Results demonstrate that CNN-LSTM forecasting achieves consistent accuracy across diverse workloads, and that overprovisioning-based admission control improves net profit while reducing SLA violations compared to conservative baselines. These findings validate the feasibility of ML-driven overprovisioning for efficient and reliable slice admission in 5G networks.
Acceleration of hidden Markov model fitting using graphical processing units, with application to low-frequency tremor classification
(2021-11) Stoltz, M; Stoltz, George G; Obara, K; Wang, T; Bryant, D
Hidden Markov models (HMMs) are general purpose models for time-series data widely used across the sciences because of their flexibility and elegance. Fitting HMMs can often be computationally demanding and time consuming, particularly when the number of hidden states is large or the Markov chain itself is long. Here we introduce a new Graphical Processing Unit (GPU)-based algorithm designed to fit long-chain HMMs, applying our approach to a model for low-frequency tremor events. Even on a modest GPU, our implementation resulted in an increase in speed of several orders of magnitude compared to the standard single processor algorithm. This permitted a full Bayesian inference of uncertainty related to model parameters and forecasts based on posterior predictive distributions. Similar improvements would be expected for HMM models given large number of observations and moderate state spaces ( states with current hardware). We discuss the model, general GPU architecture and algorithms and report performance of the method on a tremor dataset from the Shikoku region, Japan. The new approach led to improvements in both computational performance and forecast accuracy, compared to existing frequentist methodology.
Adaptive interference avoidance and mode selection scheme for D2D-enabled small cells in 5G-IIoT networks
(2024-02) Gbadamosi, SA; Hancke, GP; Abu-Mahfouz, Adnan MI
Small cell (SC) and device-to-device (D2D) communications can fulfill high-speed wireless communication in indoor industrial Internet-of-Things (IIoT) services and cell-edge devices. However, controlling interference is crucial for optimizing resource sharing (RS). To address this, we present an adaptive interference avoidance and mode selection (MS) framework that incorporates MS, channel gain factor (CGF), and power-allocation (PA) techniques to reduce reuse interference and increase the data rate of IIoT applications for 5G D2D-enabled SC networks. Our proposed approach employs a two-phase RS algorithm that minimizes the system's computational complexity while maximizing the network sum rate. First, we adaptively determine the D2D user mode for each cell based on the D2D pair channel gain ratios of the cellular and reuse mode. We compute the CGF for each cell with a D2D pair in reuse mode (RM) to select the reuse partner. Then we determine the optimal distributed power for the D2D users and IoT-user equipment using the Lagrangian dual decomposition method to maximize the network sum rate while limiting the interference power. The simulation results indicate that our proposed approach can maximize system throughput and signal-to-interference plus noise ratio, reducing signaling overhead compared to other algorithms.
Advancing ecosystem accounting in estuaries: Swartkops Estuary case study
(2023-03) Taljaard, Susan; Van Niekerk, Lara; Adams, JB; Riddin, T
Rapid degradation of ecosystems and loss of ecosystem services have sparked interest in developing approaches to report and integrate such change with socio-economic information systems, such as the System of National Accounts. Here we describe an approach and application of ecosystem accounting for individual estuaries, building on approaches previously applied at national and bay levels. Using the Swartkops Estuary as a case study, the focus is on physical accounts for ecosystem extent and condition, as well as accounts for two important ecosystem services (carbon sequestration and recreational use). Pressure accounts are also introduced to demonstrate the value of identifying key areas for management and restoration interventions in response to changes in extent and/or condition accounts. Greater resolution in these account reports, achieved through zoning, provides spatially explicit information on ecosystem assets and their services within an estuary to also inform management decision-making at local level. Further, these accounts can also inform local restoration prioritisation, in support of the UN Decade on Ecosystem Restoration (2021–2030), for example offsetting irreversibly degraded areas in one zone with restoration or maintenance of similar habitats in another.
Advocating circular economy in wastewater treatment: Struvite formation and drinking water reclamation from real municipal effluents
(2020-08) Mavhungu, A; Masindi, Vhahangwele; Foteinis, S; Mbaya, R; Tekere, M; Kortidis, I; Chatzisymeon, E
In this pilot study, the circular economy concept in wastewater treatment was examined, through a zero liquid discharge (ZLD) process where struvite was recovered and drinking water was reclaimed. A stage wise approach was followed for struvite formation and the subsequent reclamation of drinking water. Specifically, the early stages of treatment entail the synthesis of struvite via the chemical precipitation of nutrients (phosphate and ammonia), using thermally activated cryptocrystalline magnesite. Thence, reverse osmosis (RO) was employed for drinking water reclamation. With this dual approach, 3.5m3 of municipal wastewater were successfully treated at a pilot plant in South Africa, producing ~52.5 kg of struvite and ~3.4 m3 of drinking water. The operating parameters were 30 min of residence time, 0.5 g : 500 mL solid to liquid (S/L) ratio, using ambient temperature and pH. X-ray diffraction (XRD) and High Resolution Scanning Electron Microscopy (HR-SEM) coupled with electron dispersion spectroscopy (EDS) confirmed the synthesis of struvite and the presence of notable Mg/P ratios. Fourier Transform Infrared Spectrometer (FTIR) further ascertained the obtained results. Moreover, it was identified that the reclaimed water meets the South African National Standard (SANS) 241:2015 and the world health organisation (WHO) standards for drinking water. An economic analysis revealed the viability of the process, suggesting that the system could be self-sustainable. Therefore, the results of his work indicate that introducing the concept of circular economy in wastewater treatment can promote the sustainable management of the ever-increasing quantities of municipal wastewater and at the same time address problems of emerging concern, such as water scarcity and phosphate shortage.
An analysis of a cryptocurrency giveaway scam: Use case
(2024-06) Botha, Johannes G; Leenen, L
A giveaway scam is a type of fraud leveraging social media platforms and phishing campaigns. These scams have become increasingly common and are now also prevalent in the crypto community where attackers attempt to gain crypto-enthusiasts’ trust with the promise of high-yield giveaways. Giveaway scams target individuals who lack technical familiarity with the blockchain. They take on various forms, often presenting as genuine cryptocurrency giveaways endorsed by prominent figures or organizations within the blockchain community. Scammers entice victims by promising substantial returns on a nominal investment. Victims are manipulated into sending cryptocurrency under the pretext of paying for "verification" or "processing fees." However, once the funds have been sent, the scammers disappear and leave victims empty-handed. This study employs essential blockchain tools and techniques to explore the mechanics of giveaway scams. A crucial aspect of an investigation is to meticulously trace the movement of funds within the blockchain so that illicit gains resulting from these scams can be tracked. At some point a scammer wants to “cash-out” by transferring the funds to an off-ramp, for example, an exchange. If the investigator can establish a link to such an exchange, the identity of the owner of cryptocurrency address could be revealed. However, in organised scams, criminals make use of mules and do not use their own identities. The authors of this paper select a use case and then illustrate a comprehensive approach to investigate the selected scam. This paper contributes to the understanding and mitigation of giveaway scams in the cryptocurrency realm. By leveraging the mechanics of blockchain technology, dissecting scammer tactics, and utilizing investigative techniques and tools, the paper aims to contribute to the protection of investors, the industry, and the overall integrity of the blockchain ecosystem. This research sheds light on the intricate workings of giveaway scams and proposes effective strategies to counteract them.
Assessing alternative supporting organic materials for the enhancement of water reuse in subsurface constructed wetlands receiving acid mine drainage
(2022-06) Oberholzer, MM; Oberholster, PJ; Ndlela, Luyanda L; Botha-Oberholtster, AM; Truter, CJ
Acid mine drainage (AMD) is a global problem with severe consequences for the environment. South Africa’s abandoned mines are a legacy from the country’s economic dependence on the mining sector, with consequent negative impacts on ecosystems. AMD remediation includes active and passive techniques. Constructed wetlands (a passive technique) have lower operational costs but require larger spaces and longer timeframes to achieve the remediation of AMD, and are supported by anaerobic sulphate-reducing bacteria (SRB), which capable of remediating high-sulphate-laden AMD while precipitating dissolved metals from the AMD. Organic substrates supporting these activities are often the limiting factor. When enhancing existing passive AMD remediation technologies, alternative waste material research that may support SRB activity is required to support the circular economy through the reduction in waste products. Chicken feathers show potential as a substrate enhancer, boosting organic carbon availability to SRB, which sustains passive AMD treatment processes by achieving pH elevation, sulphate and metal reductions in AMD water for reuse. Microbial biodiversity is essential to ensure the longevity of passive treatment systems, and chicken feathers are proven to have an association with SRB microbial taxa. However, the longer-term associations between the AMD water parameters, microbial diversity and the selected substrates remain to be further investigated.
Assessing the nanomechanical, wear and thermal stability of Ti-Al-Si-V alloys produced via laser engineered net shaping (LENS) in-situ alloying
(2024-12) Raji, SA; Popoola, API; Pityana, Sisa L; Tlotleng, Monnamme
Titanium aluminide (TiAl) intermetallic alloys are highly recognized because of their lightweight qualities and are particularly useful for replacing heavier Nickel-based (Ni-based) superalloys in high- temperature components. This study fossed on the investigation of the nanomechanical, wear, and thermal stability of intermetallic Ti-Al-Si-V alloys fabricated by in situ alloying with elemental metal powders using the laser engineered net shaping (LENS) technology. The impact of Vanadium (V) feed rate was examined both before and during the annealing heat treatment, which involved 60mins at temperatures of 1200 and 1400°C, and furnace cooling (FC) conditions. After heat treatment (1200°C and 1400°C), it was discovered that V addition enhances the Ti-Al-Si-V alloy's nanomechanical properties. According to the nanoindentation results, the mechanical characteristics of the heat-treated samples were typically better than those of the as-deposited alloy and were equivalent to the qualities of commercially available TiAl alloys. The alloy that was heat-treated at a temperature of 1200°C exhibited better tribological and thermal stability. Lastly, the as-deposited sample performed better in terms of tribological and thermal stability aspects than the sample that was heat-treated at 1400°C.
Assessment of modern training innovations for supervisors and trainers in the South African Mining Sector
(2025-06) Van Schoor, Abraham M; De Kock, N; Khan, Sumaya; Müller, R; Van Rensburg, R; Govindasamy, K; Botha, W; Maphalala, Busisiwe V; Mpofu, Mvikel; Pelders, Jodi L; Ramparsad, S
As the mining industry modernises, skills development needs to be a priority. The aim of this paper was to develop guidelines that consider the assessment of modern training solutions for supervisors and trainers in modern mining. A literature review was conducted on best-practice criteria for the evaluation of modern mining upskilling and reskilling solutions. A draft evaluation matrix was developed based on the literature review insights and incorporated 48 best-practice criteria for the assessment of training solutions. The assessment instrument was applied to training curriculums for supervisors and trainers of two participant entities. Data gathering included assessments of the training solutions, and an industry panel review process. Strengths, weaknesses, opportunities, threats, and gap analyses were undertaken. Key insights were revealed for the respective training solutions. Recommendations included continuous review and improvement of the curriculum for alignment to mining modernisation skills needs, including consideration of modern training methodologies and facilitation; revised content and assessments; skills and training required for modernisation; tracking of graduates and learner feedback; better alignment with modernisation objectives and industry skills needs, increased focus on safety and risk assessment and control; and more immersive learning experiences. While sample training innovations were selected for evaluation, the recommendations remain relevant for training entities looking to align to their curriculum to mining modernisation skills needs and industry skills demands for modernisation.
Biowaste biorefineries in South Africa: Current status, opportunities, and research and development needs
(2023-12) Sekoa, Patrick T; Chunilall, Viren; Msele, K; Buthelezi, L; Johakimu, Jonas K; Andrew, Jerome E; Zungu, M; Moloantoa, K; Maningi, N; Habimana, O; Swartbooi, Ashton M
As one of the highest carbon-emitting nations, South Africa is working tirelessly to swiftly transition to sustainable technologies in order to strengthen its green economy initiatives. Amongst the technologies that are explored in the scientific and industrial community, biorefineries are seen as the most efficient technologies that can be used to create economic opportunities and will contribute to the advancement of a bio-based economy as they can synthesize diverse industrially-competitive products. Despite their numerous socio-economic advantages, the establishment of large-scale biorefineries in developing nations like South Africa is very scarce. Therefore, it is imperative to address the technological gaps that hinder the growth of large-scale biorefineries and provide practical solutions that could be used to solve these bottlenecks. This work provides a comprehensive review of the development of biowaste biorefinery-based technologies in South Africa. Different biowaste valorization technologies applicable to locally available organic waste streams, and the resulting market-based compounds that can be obtained from these sustainable feedstocks, are reviewed. Finally, the work provides insights into research and development needs (knowledge gaps) that should be explored by scientists and industries, as these technological solutions might propel biorefineries toward industrialization in South Africa.
Bootstrapping Siswati lexical resources from isiZulu
(2025) Wierenga, Roné; Marais, Laurette; Wilken, Ilana
IsiZulu and Siswati are closely related languages that share significant morphosyntactic characteristics. Systematic differences between these languages have been identified at the phonological and morphosyntactic levels. Due to the resource-scarce status of these languages, this similarity has led to bootstrapping of computational language resources at the morphological and syntactic levels. In this work, we investigate the feasibility of adapting lexical items in a computational lexicon from isiZulu to Siswati. We use Grammatical Framework resource grammars for both languages to analyse and transform lexical items, which are then evaluated against a parallel term list. An iterative process yields a success rate of 70.5%, indicating that this approach is largely viable as a means of significantly reducing the manual effort needed to develop lexicons for computational resources for Siswati.
Breakthrough studies for the sorption of methylene blue dye from wastewater samples using activated carbon derived from waste banana peels
(2023-05) Ramutshatsha-Makhwedzha, D; Munyengabe, A; Mavhungu, ML; Mbaya, R; Baloyi, Siwela J
In the current study, an activated carbon derived from waste banana peel using H2SO4 was applied for the first time in a packed-bed column for methylene blue (MB) dye removal from wastewater. The pore structure and surface of banana peel activated carbon (BPAC) were investigated using X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and Brunauer-Emmett-Teller analysis to discover the mechanism of MB sorption. The produced BPAC by H2SO4 activation agent has surface area of 361.86 m2/g and exhibits good thermal stability. The extent of MB breakthrough performance was examined by optimizing flow rate, bed mass, and initial concentration at pH 9. The column’s dynamics revealed a strong dependence of breakthrough curves as a function of process conditions. The breakthrough time (tb), volume of liters processed (L), and adsorption exhaustion rate all increased as bed mass increased but decreased as flow rate and initial concentration increased. Applying linear regression to the experimental data, Yoon-Nelson and Thomas’ kinetic model was used to extract column characteristic parameters that could be used in process design. Using environmental water, the waste banana peel activated carbon material demonstrated effectiveness in removing MB to below acceptable levels by processing 1.16 L of water with an initial MB concentration of 40 mg/L using 8 g of sorbent. Nitric acid (3M) was able to regenerate the exhausted bed. Moreover, the sorbent was reused four times with no significant capacity loss. It can be concluded that waste banana peel activated carbon medium is an alternative solution to remediate MB-contaminated wastewater.
Building an integrated cyber defence capability for African missions
(2022) Mtsweni, Jabu S; Thaba, James M
Cyberspace has been designated by organizations such as NATO as the fifth domain for battlespace, and many nations are already having and/or building their capabilities in the cyber defence environment in order to protect and defend their assets against any onslaught by their adversaries. It is a common belief that many African countries are not well positioned or prepared to respond effectively to cyberattacks against their citizens, critical infrastructure, and government. In many instances, the gap can be traced to the shortage of skills, lack of cybersecurity readiness and preparedness, and lack of investment in cybersecurity programmes, including policies within the military’s strategic, tactical, and operational environments. This paper seeks to present a conceptual approach into how African countries could develop a resilient cyber defence capability in order to effectively respond to constant cyberattacks. The approach is underpinned by an integrated capability management philosophy using case studies in large and complex environments, including strategic and capability development learnings from other military domains outside the African continent. It is envisaged that the output of this paper may influence and support African states in building their cyber defence capabilities in a coordinated and integrated manner.
Cellulose nanocrystals and snail shell-reinforced polyvinyl alcohol bioplastic films: Additive concentration optimization and mechanical properties assessment
(2022-07) Gbadeyan, Oluwatoyin J; Fagbemi, Olajumoke D; Jerome, Andrew E; Adali, S; Glen, B; Sithole, Bishop B
This study focused on modeling and optimization of the concentration of poly (vinyl alcohol) (PVA), cellulose nanocrystals (CNC), snail shell nanoparticles (SSN), and glycerol for the development of bioplastic films. The response surface methodology using Box–Behnken experimental design was used to investigate the effect of the independent parameters (additives concentrations) on the ultimate tensile strength and Young's modulus of fabricated bioplastic films. A varied ultimate tensile strength and Young's modulus with different component loadings was observed, proving the effect of nanoparticles loading effect on the mechanical properties of bioplastic films. The quadratic polynomial model experiment data provided a coefficient of determination (R2) of 0.795 for ultimate tensile strength and 0.732 for Young's modulus, evidencing the fitness of the models to pilot the optimization space. The optimum parameters were PVA (7.820%), CNC (1079%), SSN (1241%), and glycerol (2.657%). The ultimate tensile strength and Young's modulus of 27.2 MPa and 31.2 MPa were obtained for the developed bioplastic film with optimized concentrations of each component. The bioplastic films showed improved thermal stability and degradation. The scanning electron microscopy (SEM) imaging revealed a homogeneous dispersion of SSN and CNC in the matrix, which explained the improved properties observed.
Challenges of user data privacy in self-sovereign identity verifiable credentials for autonomous building access during the COVID-19 pandemic
(2024-03) Naicker, Denver; Moodley, Mackaylan
Self-sovereign identity is an emerging blockchain technology field. Its use cases primarily surround identity and credential management and advocate the privacy of user details during the verification process. Our endeavor was to test and implement the features promoted for self-sovereign identity through open- and closed-source frameworks utilizing a scenario of building access management to adhere to health risk and safety questionnaires during the COVID-19 pandemic. Our investigation identifies whether user data privacy could be ensured through verifiable credentials and whether business practices would need to evolve to mitigate storing personal data centrally.
Computational study of the mechanistic pathway of hydroxyl radical-initiated degradation of disperse red 73 dye
(2022-02) Wahab, OO; Olasunkanmi, LO; Govender, Krishna K; Govender, PP
The mechanisms of hydroxyl radical (·OH) degradation of disperse red 73 (DR73) dye were investigated using density functional theory (DFT) calculations. Comparative feasibility of ·OH attack at the azo (N=N) site or on a > C–N group was examined based on their energies with a view to determine the more preferred pathway for DR73 degradation and predict its degradation products. Further decomposition of the cleavage products by ·OH radical through processes such as deamination and loss of molecular nitrogen was also examined. The results showed that ·OH radical attack on DR73 is more favourable via the azo (N=N) site. However, subsequent rupture of the N=N bond was found to be kinetically and thermodynamically less favourable compared to the C–N bond rupture arising from the attack of the radical on a ring carbon attached to the azo group. Introduction of water (as a solvent) was found to produce an accelerating and stabilising effects on the N=N bond cleavage mechanism, but an inhibitory and destabilising effects on the C–N counterpart. Deamination and nitrogen evolution reactions of the primary degradation products upon further ·OH radical attack were found to be kinetically and thermodynamically feasible.
A conceptual framework for consumer IS compliance awareness: South African government context
(2021-07) Bredenkamp, IE; Kritzinger, E; Herselman, Martha E
The requirement for consumers to divulge personal data to obtain basic products/services from organizations, is becoming the norm. It has, to a large extent, benefitted consumers as it enabled organizations to profile their customers to provide them with relevant products/services and an improved shopping experience. Nevertheless, although profiling driven by big data, offers endless lists of opportunities/value through improved customer experience, it is also accompanied by many risks of which consumers are not always aware. In South Africa (SA), being a developing country, it became clear that there is a divide between the level of trust consumers extend towards organizations they transact/share personal data with and the extent to which that trust is warranted by organizational Information Security (IS) compliance efforts. Human factors significantly influence IS behaviour. Trust is a crucial human factor as it influences IS behaviour. Awareness is a powerful element that can in turn influence trust and IS behaviour. There is currently a definite lack of IS compliance awareness amongst consumers and a disregard of the cost/value benefit of IS compliance from an organizational perspective. The failure of realizing/addressing these issues in previous data protection frameworks emerged as key lessons. There is currently no government-led/sponsored IS compliance awareness and training initiatives in SA. The primary research objective of this paper is to propose a Consumer Data Protection Framework to assist the South African Government with creating IS compliance awareness amongst consumers. This Framework will be developed based on key building blocks derived from literature. Informatics and Cybernetics in Intelligent Systems.
Conceptualising a benefit assessment framework for the South African National Roads Agency Ltd SOC research and development programme
(2021-09) Rust, FC; Sono, P; Van Dijk, G G; Fourie, H; Smit, Michelle A
In low-income countries Research and Development funding is limited and has to be invested with a view of optimum return, both economic return but also “softer” benefits such as human resource development. The assessment of these benefits is therefore important for the long-term sustainability of research and development programmes. Outputs from research and development in roads and transport are often not hard products aimed for the consumer market, but also include new design methods and techniques to enhance the performance of the transport system that cannot be easily quantified with benefit cost analysis alone. The article discusses the development of a framework for the monitoring of the performance of the South African National Roads Agency Research & Development Programme. The framework consists of a Balanced Score Card and a proposed set of indicators that address benefit throughout the innovation value chain.
Considering the 'other' in wildlife crime mitigation: A South African strategy case study
(2022-01) Meissner, R; Gonçalves, Duarte PD
Actors’ worldviews are critical when developing strategies; not every actor holds the same problem perception and solution. This is the case with wildlife trafficking. Not only does the state have an interest in safeguarding South Africa’s wildlife, but other non-state actors, such as conservation interest groups, are also participants. These are some of the ‘visible’ actors with ‘power’. There also exists ‘invisible’ actors seemingly without ‘power’, such as the local communities living around conservation areas, and the wildlife itself. Poachers and crime syndicates, on the other hand, poach wildlife, such as rhino, and are ‘drivers’ of wildlife trafficking and trade. In this article, a methodology towards a deeper understanding of actors’ causal mechanism perspectives is presented. This methodology highlights the interplay between agential, ideational, material, and structural causal mechanisms and their operationalisation. Linear cause and effect relations are not the only causal types. An alternative approach, that can assist researchers and policy makers, as well as practitioners, to develop more nuanced strategies than those derived from linear causality, is advocated. The case study used in the research was the National Integrated Strategy to Combat Wildlife Trafficking. The authors’ intention is to show that the ‘othered’ influences the perspectives of the powerful and that the ‘othered’ is an important component to consider when developing policies and strategies.

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