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Verifying a terrain mapping platform for military vehicle mobility

- Mzayidume, Tulani Sijabulile

Authors: Mzayidume, Tulani Sijabulile
Date: 2016
Subjects: All terrain vehicles - Dynamics , Off-road vehicles - Dynamics , Tires - Traction , Vehicles, Military , Soil dynamics
Language: English
Type: Masters (Thesis)
Identifier: http://hdl.handle.net/10210/280261 , uj:30112
Description: M.Tech. (Electrical Engineering) , Abstract: Vehicles are critical to the military in carrying out functional capacities such as firepower, command and control, protection, sustainment, situational awareness, and intelligence. There is particular need to understand the parameters that will influence the efficient movement of a military vehicle and this can be achieved through researching tire modelling, terrain analysis, and ride comfort. Various research projects have been carried out to understand various subsystems and factors that make up a military vehicle, and they focused mainly on understanding parameters that influencing tire modelling, tire characteristics sensitivity study, terrain analysis and ride comfort. Theoretically, to understand these parameters various studies for on-road conditions have been conducted while less research on off-road conditions has been carried out. In the current century vehicle, technology designs have seen advancement through vehicle simulation, which is less time consuming and reduces the cost of development. Accurate terrain profiles are an integral part of the effective simulation as they are required input. Understanding the ability to measure valid terrain profile accurately is of fundamental importance. The first contribution of this study is introducing a validation method for off-road profilometer. The second contribution of the study is the validation of the LMT off-road profilometer. Current validation methods focused on evaluating the accuracy of on road pavement profilers. The method of calibration by excitation and validation against knows obstacles are efficient and thus in the current study this method is incorporated to introduce a validation method which does not depend on known obstacle or terrains. For off-road profiling, the challenge is that off-road terrain is random and changes after every test thus validation through comparison of known obstacle or terrain is thus not possible. The presented method in this study is the laser sensor profile acquisition method developed to validate LMT profilometer off-road, which allows for independent terrain validation and ability to quantify the error found in each measurement. Experimental and simulations are conducted on the LMT profilometer, and the validation of the device is presented, and the RMS error is used to quantify the accuracy of the instrument.
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Effective allocation of multifunction radar resources

- Molapo, Makhabane

Authors: Molapo, Makhabane
Date: 2017
Subjects: Radar - Testing , Radar - Mathematical models , Fuzzy systems
Language: English
Type: Masters (Thesis)
Identifier: http://hdl.handle.net/10210/225206 , uj:22740
Description: Abstract: The effective allocation of radar resources is essential if MFR is to realize its full potential. The MFR, aided by algorithms in electronically steered phased array technology, is capable of performing numerous, differing and potentially conflicting tasks. However, the full potential of the radar system is only realised through the ability of its scheduler to automatically manage and configure the finite resource it has available. The main purpose of this dissertation is to realize the RRM techniques for a MFR and it further investigates the efficiency of several resource management algorithms techniques by empirically comparing their effectiveness and performance. In this dissertation the measures and methods which can be used to allocate radar resource are explored; this choice of objective function is crucial as it determines which attribute is allocated resources and consequently constitutes a description of the problem to be solved. A variety of task specific and information theoretic measures are studied and compared. It is shown that by utilising as wide a variety of measures and methods as possible the radar’s multifunction capability is enhanced. The research investigates the impact of using different algorithms, by studying and observing simulations done by other researchers and finding the best performer algorithm in the uncertain and ever changing environment where MFR normally operates, and using the best possible algorithm for experimental purposes for this research, the mathematical modelling using Matlab Fuzzy logic tool box was done to observe the behaviour of the MFR under different fuzzy rules. It is discovered that fuzzy logic algorithms improves the efficiency in allocation of resources. Fuzzy logic algorithm has proved to produce noteworthy improvements in task performance, resource management and allocation. Thus fuzzy logic algorithms can be declared as the base line on which other algorithms can be compared to and the ideal algorithm to handle uncertainty and adaption to a dynamic environment, where most MFRs normally operate. , M.Ing.
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Development of transverse-laminated synchronous reluctance motor with sinusoidal anisotropic rotor for less torque ripple contents

- Muteba, Mbika

Authors: Muteba, Mbika
Date: 2017
Subjects: Rotary converters , Electric machinery, Synchronous , Electric motors, Synchronous , Reluctance motors , Electric current converters
Language: English
Type: Doctoral (Thesis)
Identifier: http://hdl.handle.net/10210/269755 , uj:28660
Description: D.Phil. (Electrical Engineering) , Abstract: This thesis presents a novel Synchronous Reluctance Motor (SynRM), which has a sinusoidal rotor lamination shape in the axial direction. The sinusoidal lamination shape is utilized to vary the magnetic flux in the q-axis direction, therefore cancelling some torque harmonics produced by stator and rotor slotting effects. A method for evaluating, both qualitatively and quantitatively, the effects of specific rotor design parameters on the performance of the synchronous reluctance machine is presented. The method uses single-and multi-factor experimental designs, with Analysis of Variance (ANOVA), and Finite Element Analysis (FEA) to determine the optimal rotor design parameter for the novel SynRM, according to a specific objective. In addition to the unique criteria applied to the novel SynRM design process, a theoretical analysis is conducted to evaluate the effect of the number of stator slots and rotor slots (number of rotor segments), stator slot and rotor cut-off openings on airgap conductance harmonics. The analytical expressions for the novel SynRM take into account the Carter’s Factors due to the slot opening on both sides of the stator and the rotor, as the torque ripple is mainly caused by the variation of the d-and q-axis inductances, the oscillation of the Carter’s factor and the oscillation of the circulating flux component along the q-axis. Due to the axial geometry design of the sinusoidal lamination shape for the proposed machine, the 3-D Finite Element Method (FEM) is used for static and dynamic analysis. Taking into account the asymmetric nature of the axial geometry design of the sinusoidal lamination shape for the proposed SynRM, a comprehensive 3-D Finite Element Analysis (FEA) is performed. This is because with most electric machines with plane symmetry, the magnetic fluxes are calculated for unit depth and multiply by the stack length to find the actual magnetic flux in...
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The impact of slow uptake of renewable energy in South Africa with emphasis on the solar energy type systems

- Mncube, Innocent Mduduzi

Authors: Mncube, Innocent Mduduzi
Date: 2015
Subjects: Solar energy , Renewable energy sources
Language: English
Type: Masters (Thesis)
Identifier: http://hdl.handle.net/10210/56132 , uj:16334
Description: Abstract: The dissertation examines the slow uptake of renewable energy in South Africa, especially solar type energy systems. It aims to identify and understand the issues and the unique dynamics involved in the local government (municipalities) since they are at the forefront of electricity distribution. The dissertation takes a qualitative research approach and a triangulation of data collection methods, combined with a relatively broad literature study to capture the complexity of the related issues. The contextual focus includes the macro-economic factors that contribute to the environment in which municipalities operate, developmental, economic, political and social aspects and the related experience of poverty, urbanization and unemployment. Furthermore, the dissertation attempts to show that a relationship exists between a slow uptake of renewable energy technologies, particularly solar energy and the loss of electricity sales revenue by municipalities in recent times. Key findings indicate that the electricity sales revenue of municipalities is affected by the introduction of renewable energy technologies. This in turn causes reluctance in promoting such technologies from the decision makers at municipal level, because electricity distribution income is a key contributor to municipal revenue without which municipalities will not be able to meet their constitutional obligations. These findings are supported by the view of this dissertation when comparing electricity sales revenue of metropolitan municipalities over the past five years and also studying municipal legal framework. A variety of related theoretical work is chosen in this dissertation as a useful framework for analysis in order to approach issues of comparing the relationship between depleting municipal electricity sales revenue and the slow uptake of the renewable energy type system with a major focus on solar energy. , M.Ing. (Engineering Electrical and Electronics)
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Optimal placement of a distributed generator on a medium voltage distribution feeder

- Lekhuleni, Menson Teddy

Authors: Lekhuleni, Menson Teddy
Date: 2016
Subjects: Distributed generation of electric power , Distributed generation of electric power - Mathematical models , Electric power systems - Automation , Newton-Raphson method
Language: English
Type: Masters (Thesis)
Identifier: http://hdl.handle.net/10210/225255 , uj:22746
Description: Abstract: There are three types of energy resources, namely, fossil fuels, nuclear energy and renewable energy. Renewable energy is divided into five technologies which are solar, hydropower, biomass, wind and tidal waves. The Middle East and Africa are considered to have good solar irradiance. The Eastern Cape and Western Cape provinces of South Africa have winds of annual average speeds of about 1.6 metres per seconds. Optimisation techniques are divided into classical and modern. Classical optimisation techniques include linear, nonlinear, integer, geometric and dynamic programming while modern optimisation includes genetic, ant colony, particle swarm and simulated annealing. Connecting distributed generators to a power system network can impact on protection, stability and power quality on the system. Three control functions that used to control distributed generators are voltage, power factor and reactive. One control function can be activated at a time. This work investigated the optimal placement of a distributed generator (DG) on a medium voltage radial feeder. Simulated annealing optimisation was used to find an optimal bus of connecting of connecting a distributed generator on a radial feeder. The optimisation technique was applied to a power flow Matlab program which incorporates Newton-Raphson method. DigSilent PowerFactory simulations software was used to validate the results which were obtained from the Matlab program. The results obtained from both the Matlab tool and DigSilent PowerFactory indicated that the optimal bus for a 14-bus radial feeder loaded at 5 MVA while using a 1.5 MW DG is bus 11. This is because connecting the distributed generator at bus 11 resulted in maximum loss reduction on the feeder. The Matlab tool proposed in this study can be used to find the optimal point where a distributed can be connected on a medium voltage radial feeder. , M.Ing. (Electrical and Electronic Engineering)
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Smart card byte code identification using power electromagnetic radiations analysis and machine learning

- Djonon Tsague, Hippolyte

Authors: Djonon Tsague, Hippolyte
Date: 2018
Subjects: Embedded computer systems - Security measures , Smart cards - Security measures , Computer security , Data protection , Data encryption (Computer science)
Language: English
Type: Doctoral (Thesis)
Identifier: http://hdl.handle.net/10210/286050 , uj:30945
Description: D.Ing. (Electrical Engineering) , Abstract: Power Analysis or Side-Channel Attack aimed at embedded systems such as smart cards has gained momentum to become a very important and well-studied area in computer security. Side-channels are unwanted and exploitable by-products information leaked from cryptographic devices that an attacker or a hacker can utilize to reveal secret information stored or processed by those devices. In most instances it is easier to acquire the secret keys hidden in cryptographic hardware from such techniques than to attempt to break the cryptographic algorithm. One such side-channel attack is the electromagnetic side-channel attack, giving rise to electromagnetic analysis (EMA). In this thesis, we take a different approach towards side-channels. Instead of exploiting side-channel to derive cryptographic keys, we present techniques, algorithms and use-cases to identify instruction-dependent information from smart card code by analyzing their electromagnetic emanation and power consumption. This has resulted in the so-called side-channel disassembler offering new applications or uses that were not previously explored in the embedded design. Although the idea of recognizing executed micro-controller instructions using side-channel analysis is not new, previous implementations reported in available literature did not yield good enough accuracy to be relevant for practical applications. Our first use-case presents the practical results of a real-life smart card malware detection. We present an implementation consisting of reconstructing a malware program executed on a smart card device using the emanated electromagnetic radiation only. This is useful in the sense that it allows network engineers to immediately detect the presence of the Sykipot malware in a smart card environment almost instantaneously. It has been demonstrated that it takes approximately 229 days for network engineers to detect a malware attack. So this implementation goes a long way towards improving such statistics. Our solution makes use of machine learning techniques applied to data involving a substantial number of correlated variables. To effectively reduce the number of variable under consideration, we use dimension reduction algorithms such as PCA and LDA. K-Nearest neighbor (k-NN) search is applied as a learning and classification technique to recognize and detect malware presence in the device. Genetic Algorithms are further applied to improve some of the k-NN limitations and shortcomings. Our implementation shows very promising results in the sense that our malware detection tool produced a recognition rate of up to 90%. The second use-case analyzes the recorded power consumption of a micro-controller to extract Hamming weights of executed instructions including operands. These Hamming weights are transformed into strings that can be used to overcome the popular dummy instruction countermeasure. Although the presented technique is only applied to the dummy and random instruction countermeasure, a similar approach can be applied to other variants of side-channel countermeasures. Such findings highlight the fact that most available countermeasures can easily be overcome. As a contribution toward building more effective countermeasures to side-channel analysis, we proposed three techniques with their simulated results. The first technique relies on mathematical equations for modeling the performance trade-offs of logic circuits. Using such equations, effective models for leakage reduction in CMOS are easily deduced. Among other, it is argued and demonstrated that the use of high dielectric constant can be a very effective technique for reducing CMOS leakages. In the second proposition, we highlight the use of strained-Si in CMOS device fabrication. In our proposition, the emphasis is on mobility enhancement as a result of strain. The study is carried out...
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Development of the unity displacement factor frequency converter

- Langa, Hendrick Musawenkosi

Authors: Langa, Hendrick Musawenkosi
Date: 2015-06-29
Subjects: Frequency changers , Electric current converters
Type: Thesis
Identifier: uj:13640 , http://hdl.handle.net/10210/13821
Description: M.Phil. (Electrical and Electronic Engineering) , There are two methods that can be used when power is converted from one frequency to another. One way uses a DC link as an intermediate stage and the other uses no intermediate stage. When no DC link exists, the conversion process is referred to as AC-AC conversion, (Cha, Enjeti & Ratanapanachote, 2004:2237). This method essentially chops the AC signal in a specific manner which yields an AC signal with a different frequency directly. Depending on how the AC signal is chopped, it would result in a varied number of wave shapes are constructed. The construction of these various wave shapes results in devices that can accomplish different tasks. One such device is called a unity displacement factor frequency converter (UDFFC). This research attempts to develop a model, to simulate and design a unity displacement factor frequency converter. The primary idea about this device is that the power factor or displacement factor is unity regardless of the load. There are three parts in the development of the UDFFC. The power circuit is an array or matrix of switches that link the three phase supply to the three phase load. The power circuit is interfaced to the control circuit which generates pulses that control the matrix of switches. The control circuit utilizes embedded control software that performs the control logic in a microcontroller. The development of the UDFFC has a potential to solve real power engineering problems, such as eliminating the DC link in a converter. This achieves the conversion of AC directly to AC in the absence of a DC link. The other major advantage is the variation of the output frequency to a desired value. The most important is that the displacement factor can be controlled as well.
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Modelling student success or failure in electrical engineering at the Vaal University of Technology using machine learning techniques

- Langa, Hendrick Musawenkosi

Authors: Langa, Hendrick Musawenkosi
Date: 2018
Subjects: Engineering students - South Africa , Engineering - Study and teaching (Higher) - South Africa - Case studies , Academic achievement - South Africa , College student development programs
Language: English
Type: Doctoral (Thesis)
Identifier: http://hdl.handle.net/10210/296332 , uj:32284
Description: Abstract: The success of students in academic institutions, colleges, universities is still a challenge that faces many of these institutions. Models have been developed and the use of machine learning techniques has been used to solve the challenge. This thesis presents a novel model, that is simple concise but captures the necessary ingredients to determine the success or failure of a student. In this thesis, a model referred to as the Academic Environment Model (AEM) is proposed and developed. This model comprises of three components, namely, the student, the lecturer and the subject. This is a compact model where the features of each component are also developed. To verify the impact of some of these features, surveys have been conducted. The concept of communities is defined as well as its relevance in the development of the academic environment model. In this theory, the concepts of community,... , D.Phil.
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Intrusion detection for unsolicited short- message services in mobile devices

- Olorunfemi, Tope Roseline

Authors: Olorunfemi, Tope Roseline
Date: 2017
Language: English
Type: Masters (Thesis)
Identifier: http://ujcontent.uj.ac.za8080/10210/384444 , http://hdl.handle.net/10210/269382 , uj:28618
Description: M.Ing. (Electrical Engineering) , Abstract: This dissertation is based on developing a mobile application by using an android studio with java programming language to detect incoming unsolicited Short Message Service (SMS) in mobile phones. The Application (APP) was developed and tested on android version 4.4 and 5.0. The results were good; and the App worked as expected. The App works in such a way that whenever there is an incoming SMS from a number which is not in the contact list, there will be room to either „allow‟ or „block‟ the incoming message from being delivered. If the user chooses to allow, the message will be delivered; and it would be accessible to the user, otherwise, the message will be blocked and not delivered; and such a contact cannot subsequently send an SMS to the mobile phone. It is believed that this App will enhance the experience of mobile-phones users; because the interface is user-friendly and easy to use.
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Delay measurement and prioritization of BRT at signalized intersection : the Johannesburg Reavaya as a case study

- Afolabi, Oluwatobi Joshua

Authors: Afolabi, Oluwatobi Joshua
Date: 2017
Subjects: Traffic engineering - Mathematical models , Transportation - Passenger traffic - Planning , Bus rapid transit - South Africa - Johannesburg - Planning , Transit-oriented development - South Africa - Johannesburg , Urban transportation - South Africa - Johannesburg
Language: English
Type: Masters (Thesis)
Identifier: http://hdl.handle.net/10210/269619 , uj:28643
Description: M.Ing. (Electrical Engineering) , Abstract: Bus Rapid Transit (BRT) is a transit system that makes use of modern and state of the art buses to deliver quick, comfortable and relatively cheap services usually at metro-level capacity. This research focused on the BRT system used in Johannesburg called the “Reavaya” (which means ‘We are going’) which is also the BRT system that was used as a case study. It is a common practice in other developed and developing countries that when a BRT system is built, a prioritized signal control at intersections that gives a right-of-way to the BRT is included on its corridors. However, as noticed at traffic intersections, the Reavaya buses were not prioritized at intersections leading to delay and more travel time of bus. The project proposed a mathematical model that measured the control delay experienced by the bus at an un-prioritized signalized intersection. The model measured the extra delay caused by the bus deceleration on approaching the un-prioritized intersection and its subsequent acceleration back to its original travel speed. The result of the model proposed when used to measure delay was then compared with the results of the Canadian model and the on-site field measurement. The effect of complexity and geometry of intersections on delay was also studied using the models. A study on the effect of active prioritization of buses at signalized intersections was also conducted using SUMO (a simulation tool) and a comparison was drawn between traffic performance at un-prioritized intersections and traffic performance at prioritized intersections. From the result, it was found that the mathematical model proposed measured more accurately the overall delay experienced by a bus at a signalized intersection when compared to other delay models and the DT (delay time) component of the proposed model was very close to the on-site field measurement value (with as little as 1% difference at some intersections). It was also found that the use of active prioritization on the Reavaya corridors has great benefits. For the corridor simulated, there was about 68% reduction of waiting time at intersections, 13% reduction in CO2 emission, 15% reduction in NOx and PMx, 12% reduction in HC and 17% reduction in CO while having little impact on the travel time of the general traffic. For all of the edges considered, the maximum increase in the general traffic travel time, occupancy and waiting time at any intersection were 16%, 20%, 19% and 15% respectively and a maximum of 15% reduction in the speed the vehicle would need to cross over any of the intersection considered. Therefore active prioritization technique is a suitable priority technique that could be deployed.
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Image classification using machine learning techniques

- Nkonyana, Thembinkosi Nelson

Authors: Nkonyana, Thembinkosi Nelson
Date: 2016
Subjects: Image processing - Digital techniques , Image analysis , Remote-sensing images , Pattern recognition systems , Machine learning
Language: English
Type: Masters (Thesis)
Identifier: http://hdl.handle.net/10210/212965 , uj:21061
Description: Abstract: Image classification entails the important part of digital image and has been very essential in the application of remote sensing systems, thus the demand for research to find advanced algorithms and tools to solve problems experienced in classification has shown great increase in interest over the years. In this day and age, remote sensing has globally being applied with the use of current advanced satellite systems and sensors, but the need to provide analysis and decision making has been a challenge. The contribution of this dissertation is an empirical comparison (evaluation) of five machine learning (ML) techniques, in terms of classifying satellite images. The ML techniques consist of Random Forest (RF), K Nearest Neighbour (k-NN), Naïve Bayes (NB), Multi-layer Perceptron (MLP) and Support Vector Machines (SVM). The evaluation of these five techniques is based on a selection of six performance measures, such as [Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Relative Absolute Error (RAE), Root Relative Squared Error (RRSE), Precision, and Receiver Operating Characteristics (ROC)] Three publicly available remote sensing datasets are utilised for this task. The experimental results show that RF achieved higher accuracy rates, with robust performance, followed by MLP, k-NN, NB and SVM classifier exhibiting the worst performance. Hence, the use of ML for image analysis and pattern recognition is a promising approach. , M.Phil. (Electrical Engineering)
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Investigation and mitigation of technical electric power losses within City Power distribution network : South African case study

- Bakana, S. R.

Authors: Bakana, S. R.
Date: 2017
Subjects: Electric power-plants - South Africa - Load , Electric power-plants - Simulation methods , Electric power-plants - Efficiency , Eskom (Firm)
Language: English
Type: Masters (Thesis)
Identifier: http://hdl.handle.net/10210/225142 , uj:22732
Description: Abstract: The national grid is found more constrained, influenced by the growth in population and electrical usage, in addition to South Africa’s electricity sole power supplier (Eskom’s) load shedding scenario due to generating constraints. As the distribution network change its normal business, energy efficiency is the dominating term and the reduction of technical losses is one of the sections that needs attention in the emerging economy of South Africa. This dissertation evaluates different loads (residential, commercial and industrial), utilizing calculations through load factor improvement and simulation (DIgSILENT) methodologies in order to develop accurate and authentic results. These results are further analysed to develop optimum solution, mainly around improving the load factor with battery energy storage by peak shaving. The dissertation focuses on improving technical losses due to circulating current (I2R), thereby improving the overall energy efficiency that can further boost the operational efficiency and planning equipment’s of the electrical network when a battery energy storage is involved. , M.Tech. (Electrical Engineering)
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GNSS-LTE/LTE-A interference mitigation : the adjacent channel rejection ratio approach

- Hlophe, Mduduzi Comfort

Authors: Hlophe, Mduduzi Comfort
Date: 2015-09-14
Subjects: Radio - Transmitter-receivers , Radio - Interference , Long-Term Evolution (Telecommunications) , Global Positioning System , Mobile communication systems
Type: Thesis
Identifier: uj:14093 , http://hdl.handle.net/10210/14525
Description: M.Ing. , The increase of interest in the development of radio communications, both terrestrial and satellite is reaching far and beyond the most optimistic expectations. There has been an accelerated emergence of newer technologies, all claiming highly coveted radio frequency spectrum resources. With the push for the development of location based services, utilizing satellite com- communications for military purposes and later for civilian use; there has been a parallel development in terrestrial communications technology making it possible to implement cost efficient reliable user systems for voice and data services ...
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