Journal Articles

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A proposed bitcoin blockchain investigation methodology: Based on a case study approach
(2025-01) Botha, Johannes G; Singh, Kreaan D; Leenen, L
Criminal investigations involving cryptocurrencies are still premature with no standard investigative process to follow. This paper proposes a high-level methodology using open-source and analysed data to perform such investigations. It focuses on situations where Bitcoin is involved, but where other similar blockchains are concerned, the technical investigator should apply this methodology only after careful consideration. A case study approach is used to illustrate a cryptocurrency scamming platform, a giveaway scam, and divorce fraud. In all the cases, one needs to follow or trace the funds on the blockchain, referred to as on-chain analysis. The end goal of on-chain analysis is to find a destination address linked to identifiable information obtained from open-source data platforms—such as websites, social media, or a cryptocurrency exchange. Law enforcement can then be engaged to instruct the exchange to reveal all personal and transactional information linked to the address through a subpoena. A successful investigation will result in criminal prosecution and a potential recovery of funds. To maintain familiar investigation processes, the researchers looked at traditional (or non-technical) as well as technical investigation techniques.
Adding up the numbers: COVID-19 in South Africa
(2022-06) Suliman, Ridhwaan; Mtsweni, Jabu S
The SARS-CoV-2 pandemic has wreaked havoc globally, with over half a billion people infected and millions of lives lost. The pandemic has also interrupted every aspect of our lives, with most governments imposing various interventions and restrictions on people’s movement and behaviour to minimise the impact of the virus and save lives. The debate among scholars on the effectiveness of the interventions and restrictions, particularly in the context of a developing country like South Africa, continues. The data and scientific evidence indicate that non-pharmaceutical interventions, and particularly the implementation and adherence thereto, may have been ineffective in terms of containment in the South African context and had minimal impact in stopping the spread of the SARS-CoV-2 virus.
Advancing cybersecurity capabilities for South African organisations through R&D
(2022-03) Dawood, Zubeida C; Mkuzangwe, Nenekazi NP
There is a growth of cyber-attacks in South Africa. Seeing that there are over 38 million Internet users in South Africa, this is no surprise. The South African government has published the National Cybersecurity Policy Framework (NCPF) and Protection of Personal Information Act (POPIA) to move towards mitigating cyber threats due to the increase of the presence of South African organisations and citizens in cyber space. This demonstrates that there is a need for organisations to have a clear roadmap to implement and improve on their own cybersecurity capabilities. South African organisations need to take a proactive stance in cybersecurity because businesses rely heavily on technology for day-to-day operations. Currently cyber-attacks cost South African organisations over R2 billion, and the current work-from-home arrangement that most organisations have implemented will only worsen the situation. While a cybersecurity roadmap will differ in every organisation based on the organisation’s vision, goals, and objectives, along with their information technology (IT) and operations technology (OT), a starting point is perhaps the identification of key research and development (R&D) areas together with key activities that organisations can focus on in order to improve their cybersecurity capabilities. Cybersecurity capabilities are tools that organisations use to strengthen their organisation and protect themselves from potential cyber threats. The purpose of this study was to investigate R&D areas that organisations should invest in for the purpose of improving their cybersecurity capabilities. There are various subfields in cybersecurity that can be explored for organisations to advance their cybersecurity capabilities. Five integral R&D dimensions were identified together with key activities and are presented and discussed. A conceptual framework is also presented which maps the R&D dimensions and activities to the main pillars of cybersecurity, i.e., People, Processes, and Technology. South African organisations could reference the framework and adapt it for their business needs to protect themselves against potential cyber threats.
An aerodynamic CFD analysis of inlet swirl in a micro-gas turbine combustor
(2023-07) Meyers, Bronwyn C; Grobler, Jan-Hendrik; Snedden, GC
A combustor was designed for a 200N micro-gas turbine [1, 2] using the NREC preliminary combustor design method [1, 2, 3]. During the design process, there are various aspects where there are no definitive methodologies for specifying the design detail, such as the design of the hole-sets, and multiple options can be derived that can satisfy the required mass flow split and pressure drop for a particular hole-set.
Aerodynamic design of an electronics pod to maximise its carriage envelope on a fast-jet aircraft
(2024-12) Du Rand, R; Jamison, Kevin K; Huyssen, Barbara
The purpose of this paper is to reshape a fast-jet electronics pod’s external geometry to ensure compliance with aircraft pylon load limits across its carriage envelope while adhering to onboard system constraints and fitment specifications. Initial geometric layout determination used empirical methods. Performance approximation on the aircraft with added fairings and stabilising fin configurations was conducted using a panel code. Verification of loads was done using a full steady Reynolds-averaged Navier–Stokes solver, validated against published wind tunnel test data. Acceptable load envelope for the aircraft pylon was defined using two already-certified stores with known flight envelopes. Re-lofting the pod’s geometry enabled meeting all geometric and pylon load constraints. However, due to the pod's large size, re-lofting alone was not adequate to respect aircraft/pylon load limitations. A flight restriction was imposed on the aircraft’s roll rate to reduce yaw and roll moments within allowable limits. The geometry of an electronics pod was redesigned to maximise the permissible flight envelope on its carriage aircraft while respecting the safe carriage load limits determined for its store pylon. Aircraft carriage load constraints must be determined upfront when considering the design of fast-jet electronic pods. A process for determining the unknown load constraints of a carriage aircraft by analogy is presented, along with the process of tailoring the geometry of an electronics pod to respect aerodynamic load and geometric constraints.
An optical gas imaging technique based on strobed illumination
(2024-12) Chirindo, Mathews; Cox, Ettienne; Duness, Kahesh
Gas leakage from equipment poses undesirable safety, environmental and operational impacts. Many optimal gas imaging techniques exist which detect and visualize gas plumes. However, most of these techniques struggle to produce clear images when the temperature gradient between the scene background and the gas plume is small. This paper presents an optical gas imaging technique that is based on strobed illumination, wherein the strobing frequency of the illuminating device is associated with the camera frame rate. Experimental test results are presented to show the improved detection of volatile organic compound gases during strobed illumination under dark room laboratory conditions where the percentage contrast value of the illuminated gas relative to its background varies by 50.8% The test results for the detection of sulphur hexafluoride gas and liquid petroleum gas under an outside environment are also presented.
Apportioning human-induced and climate-induced land degradation: A Case of the Greater Sekhukhune District Municipality
(2023-03) Kgaphola, Motsoko J; Ramoelo, Abel; Odindi, J; Mwenge Kahinda, Jean-Marc; Seetal, Ashwin R
Land degradation (LD) is a global issue that affects sustainability and livelihoods of approximately 1.5 billion people, especially in arid/semi-arid regions. Hence, identifying and assessing LD and its driving forces (natural and anthropogenic) is important in order to design and adopt appropriate sustainable land management interventions. Therefore, using vegetation as a proxy for LD, this study aimed to distinguish anthropogenic from rainfall-driven LD in the Greater Sekhukhune District Municipality from 1990 to 2019. It is widely established that rainfall highly correlates with vegetation productivity. A linear regression was performed between the Normalized Difference Vegetation Index (NDVI) and rainfall. The human-induced LD was then distinguished from that of rainfall using the spatial residual trend (RESTREND) method and the Mann–Kendall (MK) trend. RESTREND results showed that 11.59% of the district was degraded due to human activities such as overgrazing and injudicious rangeland management. While about 41.41% was degraded due to seasonal rainfall variability and an increasing frequency of droughts. Climate variability affected vegetation cover and contributed to different forms of soil erosion and gully formation. These findings provide relevant spatial information on rainfall or human-induced LD, which is useful for policy formulation and the design of LD mitigation measures in semi-arid regions.
Assessing the quality of acquired images to improve ear recognition for children
(2023-06) Ntshangase, Cynthia S; Ndlovu, Lungisani; Stofile, Akhona
The use of biometrics to secure the identity of children is a continuous research worldwide. In the recent past, it has been realized that one of the promising biometrics is the shape of the ear, especially for children. This is be cause most of their biometrics change as they grow. However, there are shortcomings involved when using ear recognition in children, usually caused by the surrounding environment, and children can be at times uncooperative, such as moving during image acquisition. Consequently, the quality of acquired images might be affected by issues such as partial occlusions, blurriness, sharpness, and illumination. Therefore, in this paper, a method of image quality assessment is proposed. This method detects whether the images are affected by partial occlusions, blurriness, sharpness, or illumination. This method assesses the quality of the image to improve ear recognition for children. In this paper, four different test experiments were performed using the AIM database, IIT DELHI ear database, and ear images collected by Council for Scientific and Industrial Research (CSIR) researchers. The Gabor filter and Scale Invariant Feature Transform (SIFT) feature comparison methods were used to assess the quality of images. The experimental results showed that partial ear occlusions has less than 16 key points, resulting in low identification accuracy. Meanwhile, blurriness and sharpness were measured using the sharpness value of the image. Therefore, if the sharpness value is below 13, it means that the image is blurry. On the other hand, if the sharpness value is greater than 110, the image quality affects the ex tracted features and reduces the identification accuracy. Furthermore, it was discovered that the level of illumination in the image varies, the higher the illumination effect, such as the value above 100 affects the features and reduces the identification rate. The overall experimental evaluations demonstrated that image quality assessment is critical in improving ear recognition accuracy.
Assessment of homegarden agroforestry for sustainable land management intervention in a degraded landscape in South Africa
(2021-12) Musvoto, Constansia D; Kgaphola, Motsoko J; Mwenge Kahinda, Jean-Marc
Agroforestry-based sustainable land management (SLM) interventions provide opportunities for tackling land degradation and its associated socio-economic issues. Agroforestry is not a guaranteed SLM fix as every agroforestry practice is not automatically relevant to each context. It is critical to identify key considerations for ensuring a good fit between agroforestry and the receiving environment. This study identifies and analyses key factors for assessing the context-specific suitability of an agroforestry practice for SLM using a case-study of homegarden agroforestry in a degraded catchment. An analysis of biophysical and socio-economic characteristics of the catchment covering land degradation, SLM aspirations of residents, agriculture and agroforestry activities was conducted through literature review, field observations, GIS and remote sensing, stakeholder engagement and a questionnaire survey. Considerations in agroforestry practice assessment for SLM include agricultural and SLM objectives, which at our study site were increased crop production and arresting soil erosion. Availability of requisite resources, namely land, water and fencing; stakeholder interest in the tree and/or crop planting, species of interest and suitability of the species for the biophysical conditions should also be assessed. We propose a framework for systematically working through the relevant factors and assessing the suitability of an agroforestry practice for SLM intervention in a specific context. Based on the framework, homegarden agroforestry is an appropriate SLM intervention as it could meet stakeholders' SLM and agricultural objectives. Identification and systematic assessment of relevant factors are critical for ensuring the acceptability of agroforestry practice in a locality and the sustainability of associated SLM interventions.
Biaxial estimation of biomechanical constitutive parameters of passive porcine sclera soft tissue
(2022-02) Ndlovu, Z; Desai, D; Pandelani, Thanyani A; Ngwangwa, H; Nemavhola, F
This study assesses the modelling capabilities of four constitutive hyperelastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96%. The polynomial (anisotropic) model gave the best correlation of 98%. However, the estimated material parameters varied widely from one test to another such that there would be need to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be need to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters, thereby making it an easier option for application of its material parameters to a finite element model and requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy was more influenced by the fiber-related properties than the background material matrix-related properties.
Biaxial estimation of biomechanical constitutive parameters of passive porcine sclera soft tissue
(2022-02) Ndlovu, Z; Desai, D; Pandelani, Thanyani A; Ngwangwa, H; Nemavhola, F
This study assesses the modelling capabilities of four constitutive hyperelastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96%. The polynomial (anisotropic) model gave the best correlation of 98%. However, the estimated material parameters varied widely from one test to another such that there would be need to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be need to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters, thereby making it an easier option for application of its material parameters to a finite element model and requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy was more influenced by the fiber-related properties than the background material matrix-related properties.
Biometric recognition of infants using fingerprint, iris and ear biometrics
(2021-02) Moolla, Yaseen; De Kock, Antonie J; Mabuza-Hocquet, Gugulethu P; Ntshangase, Cynthia S; Nelufule, Nthatheni; Khanyile, Nontokozo P
Biometric recognition is often used for adults for a variety of purposes where an individual’s identity must be ascertained. However, the biometric recognition of children is an unsolved challenge. Solving this challenge could protect children from identity theft and identity fraud, help in reuniting lost children with their parents, improve border control systems in combatting child trafficking, and assist in electronic record-keeping systems. In order to begin the development of biometric recognition systems for children, researchers collected fingerprint, iris, and outer ear shape biometric information from infants. Each modality provides different challenges. Where possible, the performance of existing hardware and software that was developed for adults was assessed with infants. Where necessary, novel hardware or software was developed. For the ear modality, existing hardware and software which have previously been applied to adults were applied to children. For the iris modality, existing hardware was used to acquire the images, while adjustments to the existing preprocessing algorithms were applied to cater for the localisation and segmentation of infant irises. For the fingerprint modality, novel hardware and image processing software were developed to acquire fingerprints from infants, and convert the images into a format which is backward compatible with existing international standards for minutiae extraction and comparison. The advantages and disadvantages of using each of these modalities during the first year of life were compared, based on both qualitative assessments of usage, and quantitative assessments of performance. While there is no conclusively best modality, recommendations of usage for each modality were provided.
CACC: Context-aware congestion control approach for lightweight CoAP/UDP-based Internet of Things traffic
(John Wiley and Sons Ltd, 2020-02) Akpakwu, GA; Hancke, GP; Abu-Mahfouz, Adnan MI
With the emerging applications of the Internet of Things (IoT), a congestion control mechanism becomes a critical phenomenon for efficient communication in networks of constrained devices. The Internet Engineering Task Force developed the constrained application protocol (CoAP) as a standard communication protocol that favors lightweight interoperability for accommodating resource‐constrained devices. However, the base CoAP specification congestion control is insensitive to various network conditions. Thus, differentiating the scenario of packet loss due to bit error rate and congestion, and identifying correct round trip time (RTT) of retransmitted message‐acknowledgement is quite essential to adapt the CoAP behavior based on the network status. In this paper, we present a context‐aware congestion control (CACC) approach for lightweight CoAP/user datagram protocol–based IoT traffic. The CACC proposes mechanisms that include retransmission timeout (RTO) estimator, retransmission count–based smoothed round‐trip‐time observation, lower bound RTO restriction approach, and aging concept. The proposed RTO estimators utilize the strong, weak, and failed RTT to identify exact network status and provide adaptive congestion control. The CACC incorporates the variable of retransmission count in request‐response interaction model to mitigate the negative variation in RTT due to the fluctuation in the IoT environment. Moreover, with lower bound RTO restriction approach, the unnecessary spurious retransmissions are avoided, and the aging mechanism limits the validity of the RTO value to improve the efficiency of the proposed scheme. The proposed model is validated against baseline CoAP and CoCoA+ using Contiki OS and the Cooja simulator. The results are impressive under different network topologies.
Conceptual mapping of the cybersecurity culture to human factor domain framework
(2023-03) Mwim, EN; Mtsweni, Jabu S; Chimbo, B
Human related vulnerability challenges continue to increase as organisations intensify their use of interconnected technologies for operations particularly due to the emergence of COVID-19 pandemic. Notwithstanding the challenge of a human problem on cybersecurity, existing cybersecurity measures predominately focused on technological solutions which on their own have proven to be insufficient. To ensure all-inclusive cybersecurity solution, efforts are shifting to accommodate human angle which complements technological efforts towards eradicating cybersecurity challenges hence the move to cybersecurity culture (CSC). The importance of the human-related factor on the security of information and IT system has been emphasised by various research leading to the development of Human Factor Diamond (HFD) framework. This paper at the conceptual level mapped the articulated list of identified CSC factors to the HFD framework to determine the CSC factors that are associated with the different domains of human factor framework. The mapping depicts that each domain of human factor framework has CSC factors associated to it. Management appeared as the domain with the predominate number of factors, followed by responsibility, environment and preparedness respectively.
Cost effective ballistic protection for vehicles
(2024-01) Jones, JD; Reinecke, John D; Pambuka, L
In the design of protected vehicles there is a constant trade-off between mobility, protection, and cost. To protect against increasing threat levels, designers are usually required to use armour materials with increased mass and thickness. However, this has a negative effect on the vehicle’s mobility. Reducing the mass of armour plates for the same level of protection usually requires the use of more expensive materials, thus increasing the cost. The aim of this project was to investigate how the areal density of armour plates, used for vehicle protection against a NATO Level 3 ballistic threat, can be reduced whilst still maintaining the required level of threat protection, and optimising cost by exploring varying material layers in a composite armour plate assembly. This work used computational modelling to evaluate protection capabilities of various combinations of lower cost materials that were then manufactured and tested. The test plate combination initially selected were based on the published computational work of Rahman et al., [2]. These proposed, multilayered, plates computationally provided a reduction in aerial density of 12% compared to equivalent homogeneous amour steel plate. Additional plate combinations, using Strenx 700E Al-7075-T6 with Kevlar and Dyneema layers, were proposed and computationally evaluated and assessed. These multilayered plates were then manufactured and subjected to ballistic tests against NATO level 3 (7.62 x 51 mm Tungsten Carbide (WC)) armour piecing rounds. None of the proposed and computationally verified plates provided the required ballistic protection. The main reason for this is ascribed to the application and use of only published material parameters and the implementation of the failure model.
The cyber threat landscape in South Africa: A 10-year review
(2021-12) Pieterse, Heloise
The world is witnessing a rise in cyber-related incidents. As information technology improves and the reliance on technology increases, the frequency and severity of cyber incidents escalate. The impact is felt globally, and South Africa is not immune to the effects. The country’s fast-paced technological evolution continues to increase the attack surface within the cyber domain. The increased attack surface is confirmed by recent cyberattacks affecting well-known and established South African organisations. This article reviews findings from an evaluation of South Africa’s cyber threat landscape that analysed 74 cyber incidents identified as occurring between 2010 and 2020. The 74 incidents are categorised according to incident type, affected sector, perpetrator type, and motivation. It is found that the most common incident type is data exposure, the most-affected sector is the public sector, the most prevalent perpetrators are hackers, and the most common motivation is criminal. The article makes recommendations about how South Africa can reduce the risk factors in its cyber threat landscape.
Cyber threats focusing on Covid-19 outbreak
(2021-02) Veerasamy, Namosha
The outbreak of the novel corona virus or Covid-19 has sparked a wave of changes. Social-distancing and remote working meant that increasingly employees and individuals were reliant on Information Communication Technologies (ICT) to connect and gain access to information. In light of the outbreak of the virus, a vast number of users were required to carry out business activities remotely. Users turned to cyberspace for communication, entertainment and information. A critical dependency for ICT emerged. This also resulted in various fraudsters, attackers and criminals seeking to take advantage of the unsettling situation. This paper takes a look at pertinent cyber threats that aimed to utilise the corona virus in order to exploit users. This work aims to show how the health crisis was manipulated for fraudulent cyber schemes, attacks and exploits, as well to create awareness on these cyber threats in order to prevent users from falling victim to them. Furthermore, the paper also looks at the approach of these attacks to identify the main characteristics for the attack execution. This can help with identification and deterrence of Covid-19 related cyberattacks.
Cyber-threat information-sharing standards: A review of evaluation literature
(2020-06) Mkuzangwe, Nenekazi N; Dawood, Zubeida C
Cyber-threat information-sharing tools, through which cybersecurity teams share threat information, are essential to combatting today's increasingly frequent and sophisticated cyber-attacks. Several cyber-threat information-sharing standards exist, but there is at present no single standard or set of standards widely adopted by organisations and by computer security incident response teams (CSIRTs) operating at organisational, sectoral, national, and international levels. This introduces an interoperability problem in respect of communication across the various organisations and CSIRTs. Harmonised adoption of threat information-sharing standards would be of great benefit to cybersecurity efforts. In an effort to support harmonised use of cyber-threat information-sharing standards, this article provides findings from a review of the extant literature on such standards.
Cybercrimes in Social Networking
(2024-04) Mmbodi, Rendani; Hlongwane, Ndabezinhle E
The ubiquity of social networking platforms in the digital age has facilitated unprecedented connectivity and communication, yet it has also given rise to a burgeoning challenge—cybercrimes within these virtual spaces. This study delves into the multifaceted landscape of cybercrimes in social networking, exploring their prevalence, types, and consequential impacts on individuals and society. Through a comprehensive analysis of survey data, interviews, and content reviews, we unveil the alarming frequency of cybercrimes, from online harassment to identity theft. The research not only examines the psychological toll on victims but also assesses the evolving tactics employed by cybercriminals. The findings underscore the imperative for collaborative efforts among individuals, platforms, and policymakers to fortify cybersecurity measures and ensure a safer digital environment for all.
A cybersecurity architecture that supports effective incident response
(2022-03) Mutemwa, Muyowa; Mtsweni, Jabu S
A Cybersecurity Operation Centre (SOC) is a centralized hub within an organisation that houses people, processes, and technologies aimed at continuous monitoring of the organization’s assets in order to prevent, detect, analyse, and respond to cybersecurity incidents against that organisation. SOCs are critical to the collection, analysis, and response to cybersecurity events and incidents faced by an organisation. This article discusses the architecture of an SOC that enables quick and timely responses to events and incidents. Firstly, the article describes an architecture of the SOC, the SOC’s processes, personnel, and technologies. Secondly, the article discusses what type of information and logs should be collected, analysed, and interpreted. Lastly the article discusses how to handle an incident through the six stages of incident response.

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