Browsing by Author "Van Niekerk, Brett."

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Blind iterative multiuser detection for error coded CDMA systems.
(2005) Van Niekerk, Brett.; Mneney, Stanley Henry.
Mobile communications have developed since the radio communications that were in use 50 years ago. With the advent of GSM, mobile communications was brought to the average citizen. More recently, COMA technology has provided the user with higher data rates and more reliable service, and it is apparent that it is the future of wireless communication. With the introduction of 3G technology in South Africa, it is becoming clear that it is the solution to the country's wireless communication requirements. The 3G and next-generation technologies could provide reliable communications to areas where it has proven difficult to operate and maintain communications effectively, such as rural locations. It is therefore important that the se technologies continue to be researched in order to enhance their capabilities to provide a solution to the wireless needs of the local and global community. Whilst COMA is proving to be a reliable communications technology, it is still susceptible to the effects of the near-far problem and multiple-access interference. A number of multiuser detectors have been proposed in literature that attempt to mitigate the effects of multiple-access interference. A notable detector is the blind MOE detector, which requires only the desired user 's spreading sequence , and it exhibits performance approximating that of other linear multiuser detectors. Another promising class of multiuser detector operate using an iterative principle and have a joint multiuser detection and error-correcting coding scheme. The aim of this research is to develop a blind iterative detector with FEC coding as a potential solution to the need for a detector that can mitigate the effects of interfering users operating on the channel. The proposed detector has the benefits of both the blind and iterative schemes: it only requires the knowledge of the desired user ' s signature, and it has integrated error-correcting abilities. The simulation results presented in this dissertation show that the proposed detector exhibits superior performance over the blind MOE detector for various channel conditions. An overview of spread-spectrum technologies is presented, and the operation of OS-COMA is described in more detail. A history and overview of existing COMA standards is also given . The need for multiuser detection is explained, and a description and comparison of various detection methods that have appeared in literature is given. An introduction to error coding is given , with convolutional code s, the turbo coding concept and method s of iterative detection are described in more detail and compared, as iterat ive decoding is fundamental to the operation of an iterative COMA detector. An overview of iterative multiuser detection is given , and selected iterative methods are described in more detail. A blind iterative detector is proposed and analysed. Simulation results for the propo sed detector, and a comparison to the blind MOE detector is presented, showing performance characteristics and the effects of various channel parameters on performance. From these results it can be seen that the proposed detector exhibits a superior performance compared to that of the blind MOE detector for various channel conditions. The dissertation is concluded, and possible future directions of research are given.
Cyber-security and governance for industrial control systems (ICS) in South Africa.
(2016) Pretorius, Barend Hendrik.; Van Niekerk, Brett.; Naidoo, Karna.
Industrial control systems (ICS) and supervisory, control, and data acquisition (SCADA) systems have evolved from operating in a relatively trusting environment to the current prevalence of public networks. Cyber-threats are evolving to become more sophisticated. The Stuxnet malware brought home how vulnerable ICS/SCADA systems potentially are. There is no or limited information available as to the current state of ICS/SCADA in South Africa including the factors influencing ICS/SCADA and how they are secured and governed. Due to the nature of the systems, ICS/SCADA cyber-security and governance faces additional challenges compared to the corporate networks, and critical systems may be left exposed. There exists control frameworks internationally, however there are new South African legislation that needs to be taken into account. South Africa is also falling behind in cyber-security, therefore there is a concern in securing ICS controlling key infrastructure critical to the South African economy as there are little known facts about this. This aim of the study is to assess the current state of ICS/SCADA in South Africa, determine the main governance frameworks employed, and to develop a control framework addressing the shortfalls. Elements of the Technology Acceptance Model (TAM) and the Protection Motivation Theory (PMT) are used to guide the study. Quantitative methods are used to determine the perceived susceptibility, security confidence, and governance for ICS/SCADA environment. Qualitative methods were used to review the current control frameworks, standards and legislation relevant to this environment. The study found that the top threat/risk for ICS/SCADA are malware and the top vulnerability is unpatched systems. Furthermore, the framework used most in South Africa to secure and govern ICS/SCADA environments are Control Objectives for Information and Related Technology (COBIT) and from the document analysis the best suited framework overall is Centre for the Protection of National Infrastructure (CPNI). Taking these frameworks into account as well as relevant risks, threats and vulnerabilities, a consolidated framework aligned to South Africa were developed suggesting leading practices for securing and governing ICS/SCADA systems in South Africa.
Investigating machine and deep-learning model combinations for a two-stage IDS for IoT networks.
(2021) Van der Walt, André.; Quazi, Tahmid Al-Mumit.; Van Niekerk, Brett.
By 2025, there will be upwards of 75 billion IoT devices connected to the internet. Notable security incidents have shown that many IoT devices are insecure or misconfigured, leaving them vulnerable, often with devastating results. AI’s learning, adaptable and flexible nature can be leveraged to provide networking monitoring for IoT networks. This work proposes a novel two-stage IDS, using layered machine- and deep-learning models. The applicability of seven algorithms is investigated using the BoT-IoT dataset. After replicating four algorithms from literature, modifications to these algorithms' application are then explored along with their ability to classify in three scenarios: 1) binary attack/benign, 2) multi-class attack with benign and 3) multi-class attack only. Three additional algorithms are also considered. The modifications are shown to achieve higher F1-scores by 22.75% and shorter training times by 35.68 seconds on average than the four replicated algorithms. Potential benefits of the proposed two-stage system are examined, showing a reduction of threat detection/identification time by 0.51s on average and an increase of threat classification F1-score by 0.05 on average. In the second half of the dissertation, algorithm combinations, layered in the two-stage system, are investigated. To facilitate comparison of time metrics, the classification scenarios from the first half of the dissertation are re-evaluated on the test PC CPU. All two-stage combinations are then tested. The results show a CNN binary classifier at stage one and a KNN 4-Class model at stage two performs best, outperforming the 5-Class (attack and benign) system of either algorithm. This system's first stage improves upon the 5-Class system's classification time by 0.25 seconds. The benign class F1-score is improved by 0.23, indicating a significant improvement in false positive rate. The system achieves an overall F1-score of 0.94. This shows the two-stage system would perform well as an IDS. Additionally, investigations arising from findings during the evaluation of the two-stage system are presented, namely GPU data-transfer overhead, the effect of data scaling and the effect of benign samples on stage two, giving a better understanding of how the dataset interacts with AI models and how they may be improved in future work.
Status of implementation of ERP within the SMME consulting engineering sector.
(2014) Govender, Deon.; Van Niekerk, Brett.
Most companies have identified the need to incorporate Information technology (IT) in their companies in order to stay competitive in the current corporate world. The introduction of the Enterprise Resource Planning (ERP) systems as a technological tool to enable competitiveness for enterprises provided many businesses with growth opportunities. For several micro, small and medium enterprises (SMMEs) it has, however, become almost impossible to implement ERP systems due to perceived high cost, lengthy timelines and high failures rates. Moreover, even though research has been conducted regarding these systems, literature on implementation methods are not extensive, thus making it complicated for enterprises to properly assess their decisions before considering installing the system. This study intended to study the status quo of ERP systems amongst SMMEs in the consulting engineering sector with an aim of also investigating possible challenges leading to non-implementation and benefits regarding the systems for those enterprises that have implemented the systems. The study incorporated a quantitative approach to study and was conducted amongst the consultants in the engineering sector involving 37 companies to which questionnaires were electronically distributed. The findings in this study indicated that there are still many companies within the engineering sector that have not yet implemented ERP systems. The perceived broad challenges with regards to ERP systems non-implementation included high costs, the complex nature of the systems, lack of training for end users and lack of involvement from top management. The recommendation was that there should be more involvement of experts in providing the industry with updated research about that value of having ERP systems installed in their companies.
A study of business-to-business extranet usage at Engen Petroleum Ltd.
(2013) Khanyile, Mduduzi.; Van Niekerk, Brett.
E-Commerce has revolutionised the manner in which modern business is conducted, with the extranet as one of the enabling tools. Concurrently, there has been an evolution in the methods of business-to-business buying, from telesales, to fax systems, and email systems, through to online buying systems. The adoption and utilisation of the extranet system has been widespread in the developed nations, however, are these trends similar in the developing countries? The aim of this study was to evaluate the adoption and utilisation trends of the extranet system by the customers of Engen Petroleum, Ltd, after the roll-out to key customers in 2002. The approach for this research was a quantitative and descriptive study, in order to serve the purpose of measuring and understanding the underlying reasons for the adoption and utilisation of the Engen extranet. The selected sampling method was a census type in order to achieve the required sample size. The total size of the active population was 56; a sample size of 49 was recommended for a 5% margin of error and for a 95% confidence interval. Data collection was conducted using an online, structured questionnaire, which was emailed to the participants. Of the total number of 56 possible participants, 47 customers participated in the survey, which made an 84 % response rate. The technology acceptance model (TAM) and the task technology fit (TTF) were the models used to conduct the research. The key outcome of the study showed poor utilisation of the Engen extranet tool, which meant that extranet adoption process at Engen is evolutional rather than revolutional. The survey showed that there was a positive perceived usefulness and intention to use the Engen extranet tool; however, there was negative perceived ease of use and task technology fit. It was concluded that the utilisation may be improved with more training and support especially among the buyers above 40 years of age. In order to leverage on the positive intention to use and perceived usefulness, it was recommended that the task technology fit could be improved, by enhancing functionality of the Engen extranet, using value-added services on the extranet website.
Vulnerability assessment of modern ICT infrastructure from an information warfare perspective.
(2011) Van Niekerk, Brett.; Maharaj, Manoj Sewak.
The overall objective of the study is to provide a vulnerability assessment of the mobile communications infrastructure to information warfare attacks; this study has a South African focus. The mobile infrastructure was selected as the infrastructure and mobile devices incorporate the majority of modern ICT technologies, namely social networking, wireless connectivity and mobility, mass storage, as well as the telecommunications elements. The objectives of the study are to: Propose a new information warfare model, and from this deduce a vulnerability assessment framework from the specific information warfare perspective. These are the guiding frameworks and model for the study. Gather information regarding threats and vulnerabilities, with particular focus on potential use in information warfare and relevance to South Africa. Establish the criticality of the mobile infrastructure in South Africa. Use the gathered information in the vulnerability assessment, to assess the vulnerability of the mobile infrastructure and related devices and services. The model and framework are generated through desk-based research. The information is gathered from research protocols that are relevant to both research and risk and vulnerability assessment, these include: expert input through interviews and a research workshop, incident and trend analyses through news and vendor reports and academic publishing, computer simulation, questionnaire survey, and mathematical analyses. The information is then triangulated by using it in the vulnerability assessment. The primary and secondary data shows that attacks on confidentiality are the most prevalent for both computer-based networks and the mobile infrastructure. An increase in threats and incidents for both computer and mobile platforms is being seen. The information security trends in South Africa indicate that the existing security concerns are likely to worsen, in particular the high infection rates. The research indicates that the mobile infrastructure is critical in South Africa. The study validates the proposed framework, which indicates that South Africa is vulnerable to an information warfare attack in general. Key aspects of vulnerability in the mobile infrastructure are highlighted; the apparent high load of the mobile infrastructure in South Africa can be seen as a high risk vulnerability. Suggestions to mitigate vulnerabilities and threats are provided.