SUNScholar - Browsing by Author "Booysen, Marthinus J."

Browsing by Author "Booysen, Marthinus J."

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An adaptive transportation prediction model for the informal public transport sector in Africa
(IEEE, 2014-10) Ndibatya, I.; Booysen, Marthinus J.; Quinn, J.
The informal public transport sector in Sub-Saharan Africa is responsible for transporting the overwhelming majority of the workforce. Often, passengers have to wait for hours for taxis to coincidentally pass by to pick them up, making the transport mode notoriously inefficient. Despite its relevance and impact, the sector is afforded little attention in terms of regulation, development and organization, giving rise to a complex and inefficient system that affects millions of people. In fact, little is known about the industry. To advance understanding of this system, minibus taxis were equipped with tracking devices in this study. Tracking data was then used to develop a model that describes the transport network – essentially finding patterns in the apparent chaos for the potential benefit of its users. The adaptive model uses unsupervised learning to predict the informal stages in the city and provide travelers with intelligence on the best time and place to get transport, thereby reducing the waiting time at the taxi rank and the informal roadside stops. Experimental results show 70.4% model accuracy in dynamically learning the taxi behavior and accurately predicting the best places to get taxis at a given time of the day.
Auditory intelligent speed adaptation for long–distance informal public transport in South Africa
(IEEE, 2016-04) Ebot Eno Akpa, N. A.; Booysen, Marthinus J.; Sinclair, M.
ENGLISH ABSTRACT: Informal transport refers to the collective passenger road transport industry with little or no regulatory control of its operations, usually characterised by unplanned and ad-hoc service delivery. The notoriously dangerous informal transport industry in South Africa – dominated by minibus taxis – has been shown to disregard the posted speed limit on long-distance trips. Not only do they frequently exceed the differentiated speed limit imposed on minibus taxis, but also the speed limit imposed on normal passenger vehicles. This paper evaluates the impact of an auditory Intelligent Speed Adaptation (ISA) intervention, applied at various intensity levels, on the speeding behaviour of this seemingly intransigent mode of transport. The experiment evaluates the behaviour on the R61 between Beaufort West and Aberdeen. We evaluate the speeding distributions, speeding frequencies, speed percentiles, mean speeds, and the statistical relevance of key metrics. We find that the auditory intervention has a clear impact on speeding behaviour, both when applied at an audible level that can be drowned out by a radio, and even greater impact at a loud level. The impact on speeding is significant, with speeding frequency (both time and distance) reducing by over 20 percentage points.
Canary in the coliform mine : exploring the industrial application limits of a microbial respiration alarm system
(Public Library of Science, 2021-03-04) Stone, Wendy; Louw, Tobi M.; Booysen, Marthinus J.; Wolfaardt, Gideon M.; Zhang, Dawei
Fundamental ecological principles of ecosystem-level respiration are extensively applied in greenhouse gas and elemental cycle studies. A laboratory system termed CEMS (Carbon Dioxide Evolution Measurement System), developed to explore microbial biofilm growth and metabolic responses, was evaluated as an early-warning system for microbial disturbances in industrial settings: in (a) potable water system contamination, and (b) bioreactor inhibition. Respiration was detected as CO₂ production, rather than O₂ consumption, including aerobic and anaerobic metabolism. Design, thresholds, and benefits of the remote CO₂ monitoring technology were described. Headspace CO₂ correlated with contamination levels, as well as chemical (R² > 0.83–0.96) and microbiological water quality indicators (R² > 0.78–0.88). Detection thresholds were limiting factors in monitoring drinking water to national and inter- national standards (0 CFU/100 mL fecal coliforms) in both open- (>1500 CFU/mL) and closed-loop CO₂ measuring regimes (>100 CFU/100 mL). However, closed-loop detection thresholds allow for the detection of significant contamination events, and monitoring less stringent systems such as irrigation water (<100 CFU/mL). Whole-system respiration was effectively harnessed as an early-warning system in bioreactor performance monitoring. Models were used to deconvolute biological CO₂ fluctuations from chemical CO₂ dynamics, to optimize this real-time, sustainable, low-waste technology, facilitating timeous responses to biological disturbances in bioreactors.
Capacitive seat sensors for multiple occupancy detection using a low-cost setup
(IEEE -- Institute of Electrical and Electronics Engineers, 2013-02) Zeeman, Adriaan Siebrits; Booysen, Marthinus J.; Ruggeri, Giuseppe; Lagana, Bruno
The Minibus public transportation sector and road safety remains a significant challenge in Africa. We propose a low cost system to monitor the taxi industry and encourage safe driving. A low cost capacitive proximity sensor for seat occupancy detection based on the loading mode capacitive sensing technique is designed. The capacitive sensor uses a single electrode to detect an occupant. We use ZigBee modules for a dynamic wireless system integration where sensors can be added or removed without modifications. A mathematical model of the capacitive sensor is developed and we determine the capacitance on the sensor’s electrode. The occupied capacitance is double the unoccupied capacitance. Our results show that the proposed capacitive sensor can distinguish clearly between an unoccupied and occupied seat.
Combining speed and acceleration to detect reckless driving in the informal public transport industry
(IEEE -- Institute of Electrical and Electronics Engineers, 2013-10) Zeeman, A. S.; Booysen, Marthinus J.
The informal transport industry in Sub-Saharan Africa is notoriously dangerous, leading to many fatalities annually. This paper presents an innovative way of monitoring driver behaviour, in real-time, by taking into account road design standards, vehicle dynamics, and passenger comfort. Two models are presented that each combines acceleration and speed data into an erratic driving detection algorithm. The first model is developed though the evaluation of empirical results taken from trips in a minibus taxi, and subjectively gauging recklessness from a passenger’s perspective. The second model presents a novel use of commonly used civil engineering principles, used in road design. Evaluation of the models, using actual minibus data, demonstrates that both successfully detect reckless driving, but the second model proves to be simpler and less processor intensive.
Correlating sound and flow rate at a tap
(Elsevier, 2015-09) Jacobs, H. E.; Skibbe, Y.; Booysen, Marthinus J.; Makwiza, C.
Laboratory tests were carried out to record the sound of water flowing through a tap and the corresponding flow rate. The results were analysed to determine a mathematical relationship between the sound signal and the flow rate. Three models, based on Fourier transforms of data in the frequency domain, were devised to estimate the flow rate of water as a function of the audible sound signal properties. The model was verified against independently recorded data from the experiments. An average error of 15% was determined when results were verified against 5 independently recorded data points. The hypothesis that actual flow rate could be estimated through the analysis of the recorded sound signal pattern was proven correct, but the accuracy of the results was relatively poor compared to mechanical meters. This study set the scene for further research into the use of microphones to assess outdoor water use.
Detecting potholes using simple image processing techniques and real-world footage
Nienaber, S.; Booysen, Marthinus J.; Kroon, R. S.
Potholes are a nuisance, especially in the developing world, and can often result in vehicle damage or physical harm to the vehicle occupants. Drivers can be warned to take evasive action if potholes are detected in real-time. Moreover, their location can be logged and shared to aid other drivers and road maintenance agencies. This paper proposes a vehicle-based computer vision approach to identify potholes using a window-mounted camera. Existing literature on pothole detection uses either theoretically constructed pothole models or footage taken from advantageous vantage points at low speed, rather than footage taken from within a vehicle at speed. A distinguishing feature of the work presented in this paper is that a thorough exercise was performed to create an image library of actual and representative potholes under different conditions, and results are obtained using a part of this library. A model of potholes is constructed using the image library, which is used in an algorithmic approach that combines a road colour model with simple image processing techniques such as a Canny filter and contour detection. Using this approach, it was possible to detect potholes with a precision of 81.8% and recall of 74.4.%.
Detection of reckless driving in the Sub-Saharan informal public transportation system using acceleration-sensing telematics
(IEEE -- Institute of Electrical and Electronics Engineers, 2013-07) Schietekat, Justin M.; Booysen, Marthinus J.
Many lives are lost annually in Sub-Saharan Africa’s unique and vibrant informal public transportation system due to accidents caused by reckless driving, fatigue, and illegal overloading. Fleet management has been used extensively to determine the location of mobile assets in the event of theft, or as part of operational management. One of the main objectives of the work presented in this paper, is to build on existing fleet management systems to improve safety and drastically reduce road accidents and the unnecessary loss of lives. Through a thorough literature survey it was concluded that existing work on vehicle tracking and reporting systems, do not use accelerometers to monitor or detect reckless driving, despite the obvious advantages. Similar to other tracking devices, this project uses global positioning to determine position and velocity, but this project also incorporates the use of a 3-axis accelerometer augmented by a theoretical behavioral model to detect and report reckless behavior to a central online server. The accelerometer results show a clear difference between safe and reckless driving.
Drone-based traffic flow estimation and tracking using computer vision
De Bruin, A.; Booysen, Marthinus J.
Traffic management has become increasingly important with growth in vehicle numbers unmatched by investment in infrastructure. A large part of management is measuring traffic flow. Video footage of traffic flow is normally manually checked to determine key traffic metrics, consuming many human hours. Moreover, installation and maintenance cost of recording equipment and supporting infrastructure is substantial, especially in the Sub-Saharan context. This paper proposes a novel solution to automate traffic flow estimation, using computer vision. The paper also introduces the notion of making the recording equipment mobile by using drone-based equipment, negating the need for fixed recording installations. The results demonstrate measurement accuracies of 100% down to 81% from ideal to worst case conditions, and successful implementation of drone control algorithms.
The effect of awareness at the medium access control layer of vehicular ad-hoc networks
(Stellenbosch : Stellenbosch University, 2013-12) Booysen, Marthinus J.; Van Rooyen, G-J.; Zeadallly, S.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
ENGLISH ABSTRACT: The hidden terminal problem, coupled with high node mobility apparent in vehicular networks, present challenges to e cient communication between vehicles at the Medium Access Control (MAC) layer. Both of these challenges are fundamentally problems of lack of awareness, and manifest most prominently in the broadcasting of safety messages in infrastructure-free vehicle-to-vehicle communications. The design of existing contention-free and contention-based MAC approaches generally assumes that nodes that are in range of one another can take steps to coordinate communications at the MAC layer to overcome the hidden terminal problem and node mobility. Unicasting with the existing MAC standard, IEEE 802.11p, implicitly assumes an awareness range of twice the transmission range (a 1-hop awareness range) at most, since handshaking is used. For broadcasting, the assumption implies an awareness range that is at most equal to the transmission range, since only carrier sensing is used. Existing alternative contention-free approaches make the same assumption, with some protocols explicitly using a 1-hop awareness range to avoid packet collisions. This dissertation challenges the convention of assuming that a 1-hop awareness range is su cient for networks with high mobility, such as VANETs. In this dissertation, the impact of awareness range and management of the awareness information on MAC performance is researched. The impact of the number of slots that is required to support the awareness range is also evaluated. Three contention-free MAC protocols are introduced to support the research. The rst is an improved version of an existing MAC method, which is used to demonstrate the e ects on performance of changes to awareness management. The second MAC uses three competing processes to manage awareness information. The second MAC is designed for a con gurable awareness range and con gurable number of slots, and is used to evaluate the e ects of awareness range and number of slots on MAC performance. The third MAC is random access based and is used to evaluate the impact on performance of removing awareness completely. An analytical model is developed to support the simulated results. The simulation results demonstrate that awareness range, awareness information management, and number of slots used are key design parameters that signi cantly impact on MAC performance. The results further show that optimal awareness-related design parameters exist for given scenarios. Finally, the proposed contention-free and random access MAC methods are simulated and performance compared with IEEE 802.11p. All three outperform the contentionbased standard IEEE 802.11p.
Energy perceptions in South Africa: An analysis of behaviour and understanding of electric water heaters
(Elsevier, 2016-03) Nel, P. J. C.; Booysen, Marthinus J.; Van der Merwe, B.
Using data from an online national survey conducted in South Africa, this paper aims to investigate: the awareness of energy savings measures for electric water heaters (EWHs); whether or not consumers are implementing suggested measures; and if consumers understand and effectively control their EWHs’ energy usage. Additionally, the data is used to determine the success of educational and rebate programmes aimed at reducing residential energy usage and to determine possible motivations for encouraging users to reduce or alter their EWH energy and warm water consumption. The results of this questionnaire indicate that: convenience is a key factor in consumers’ willingness to implement curtailment actions; users don’t understand the energy consumption of their EWHs; and they don’t know how to control their EWHs efficiently.
Evaluation of next-generation low-power communication technology to replace GSM in IoT-applications
(Institution of Engineering and Technology, 2019) Durand, Thomas G.; Visagie, Lourens; Booysen, Marthinus J.
ENGLISH ABSTRACT: The large demand for smart metering and control, asset tracking, remote monitoring, and other applications has resulted in the emergence of innovative new internet of things (IoT) low-power wide-area networks (LPWANs) featuring low power consumption, low cost, high scalability and low data rate transmissions. This article compares the performance of LoRaWAN, Sigfox, and NB-IoT as emerging technologies, in terms of power consumption, throughput, scalability, and range. For practical reasons, the comparison also includes cellular GPRS. Although GPRS does not fit the description of LPWAN technologies, it is a legacy method for IoT communications and provides insight into application areas where LPWAN technology can be applied. The study gives a clear comparative overview of the advantages and shortcomings of the various communication networks and highlights the most suitable applications cases for each technology on the basis of the tested metrics.
Household electricity and water monitor and control with cellular communications and web interface
(IEEE -- Institute of Electrical and Electronics Engineers, 2014-01) Muller, R. I.; Booysen, Marthinus J.
The availability and depletion of natural resources is increasingly punted as the limiting factor for sustainability. A lot of focus is currently placed on the role and effect of fossil fuels as well as water conservation. One way to affect prudence with these scarce resources is to generally create timely awareness of consumption thereof, and also the related cost for the consumers. Existing metering solutions for electrical energy and water are often manually read by officials, and the information difficult to digest. Moreover, billing information, which serves as feedback, lags consumption by several weeks. Smart meters address many of these challenges by enabling electronic and real-time metering, but are still prohibitively expensive. In this paper, a low-cost power meter is discussed and also a novel low-cost water flow meter is developed to integrate into a household smart metering system. Electricity supply to appliances as well as the main water supply is controlled through relays and a valve. The whole system is connected to the Trintel SMART web platform by means of cellular communications from where end-users can manage their own energy and water usage. The results demonstrate that the smart metering system provides a functional, accurate and less expensive alternative to household metering. Further improvements on the system are also suggested.
ICT-enabled solutions for smart management of water supply in Africa
(2014-12) Nel, P. J. C.; Booysen, Marthinus J.; Van der Merwe, B.
ENGLISH ABSTRACT: Pervasive and ubiquitous technologies that include mobile device applications, machine to machine communications, and cloud computing, are increasingly used for cost-effective data aggregation and information dissemination. Recently, this trend has started to gain momentum in the water sector and is being used for various management and monitoring tasks, such as remote leakage detection, automated meter reading and enhanced usage feedback to water users. This paper analyses the challenges faced by various stakeholders (consumers, utilities, etc.) in the water supply industry. Application of the said technologies is then proposed to address these unique challenges and the varying data needs of all stakeholders. An example solution, with a mobile device application and supporting cloud computing solution, is developed and presented as a proof-of-concept to further illustrate the potential use of ICT for water supply management.
The impact of average speed over distance (ASOD) systems on speeding patterns along the R61
(2014-12-10) Ebot Eno Akpa, N. A.; Booysen, Marthinus J.; Sinclair, M.
ENGLISH ABSTRACT: Speeding is considered to be a major contributing cause of road fatalities in Sub-Saharan Africa and South Africa in particular. The minibus taxi industry is a vibrant yet partly informal sector of public transport in South Africa, which has been associated with speed-related road fatalities. Although countermeasures have been implemented to address speeding, they have not led to significant reduction in road fatalities and adherence to legal speed limits. Among the countermeasures deployed on some highways is the Average Speed Over Distance (ASOD) system which uses cameras to enforce speed limits. In this paper, historical probe data is used to evaluate the impact of the ASOD system on speed profiles of passenger vehicles. The data also consists of speed, time and location information gathered by navigation and fleet management devices that were installed in minibus taxis. The evaluation is based on spatial differentiation (the impact on the enforcement site with ASOD versus the control site without ASOD) and time differentiation (the impact before and during ASOD enforcement). For passenger vehicles, the results show that the presence of ASOD systems caused a reduction in mean speeds and ensured compliance with speed limits at enforcement and control sites. On the other hand, the system appears to have no influence on minibus taxis, with high, yet similar average speeds measured in the enforcement and control sites during ASOD enforcement.
Impact of Neighbor Awareness at the MAC Layer in a Vehicular Ad-hoc NETwork (VANET)
(IEEE -- Institute of Electrical and Electronics Engineers, 2013-06) Booysen, Marthinus J.; Zeadally, Sherali; Van Rooyen, Gert-Jan
Despite various proposed Medium Access Control (MAC) approaches, efficient medium access in VANET remains a significant challenge, especially for the broadcast of safety messages. A key contributing factor to packet loss is the hidden terminal problem, which is exacerbated by the high node mobility apparent in VANET. Since the hidden terminal problem is fundamentally a problem of lack of awareness, this work evaluates the effects of increased neighbor awareness at the MAC layer. An increased awareness of neighboring nodes’ slot allocation in a TDMA-based MAC, directly impacts on the number of available slots. Therefore, the effects of TDMA frame size is also evaluated for different awareness ranges. To support the analysis, a TDMA-based MAC with configurable neighbor awareness and configurable TDMA frame size is introduced. The impact is assessed using the packet delivery ratio, receiver throughput, and end-to-end latency. The results show packet delivery ratio and receiver throughput to increase for increased awareness ranges, up to an optimal of 2 hops, after which performance worsens. An increase in TDMA frame size leads to an increase in packet delivery ratio for small awareness ranges, and an oscillating increase for large awareness ranges. The receiver throughput also initially increases for an increased TDMA frame size, but reaches an optimum,also at 2 hops.
Informal public transport -- Safety measures
(2014-07) Zeeman, A. S.; Booysen, Marthinus J.
The informal transport industry in Sub-Saharan Africa is notoriously dangerous, leading to many fatalities annually. This paper presents an innovative way of monitoring driver behaviour, in real-time, by taking into account road design standards and vehicle dynamics. A theoretical model is presented that combines acceleration and speed data into an erratic driving detection algorithm. The model presents a novel use of commonly used civil engineering principles, used in road design. Evaluation of the models, using actual minibus taxi data, demonstrates that it successfully detect reckless driving. An online platform is presented to visualise the tracked vehicle and the driving behaviour.
Informal public transport in Sub-Saharan Africa as a vessel for novel intelligent transport systems
(IEEE -- Institute of Electrical and Electronics Engineers, 2013-10) Booysen, Marthinus J.; Andersen, S. J.; Zeeman, A. S.
Developed countries have lead the way in the implementation of Intelligent Transport Systems, with the objectives of improving safety, efficiency, and environmental impact of transport. With the developing world entering the fray, the questions are: Is ITS in its current form relevant to the developing world? These regions face challenges that are different to that of the developed world, and are unique in their own ways. Many of the regions are evolving novel and innovative solutions to deliver on ITS objectives. In this paper we explore the informal public transport sector in Sub- Saharan Africa, which is in many ways unique to that of the developing world. We highlight some of the unique aspects, and highlight the dire safety and efficiency challenges that the sector faces. Mindful of the regional limitations, we introduce and discuss novel ITS solutions, which can be used to address these challenges. We also share some of the initial results observed through initial experimentation with one of the solutions.
An intelligent water heater with wi-fi access to support demand-side management
(2015-01) Brown, J. W. K.; Booysen, Marthinus J.
In the current climate of energy shortages and attempts to reduce electricity consumption, demand-side management has proven to be effective and popular. One implementation of demand-side management has been to provide the end-user with control over the ubiquitous houshold water heater (called geysers in South Africa). This paper presents a novel way to interact with water heaters, in which water heater control and monitoring is provided on a website that is accessible through a Wi-Fi hotspot interface. Both of these are hosted by the processor that controls electricity supply, tank temperature, and water supply; and monitors electricity consumption, water consumption, inlet, outlet and tank temperatures. The proposed system also provides protection against inevitable mechanical failure of the water heater, by detecting leaks and bursts, and by stopping water and electricity supply in such scenarios. This paper shows that the proof of concept is realisable in terms of cost, functionality, and energy savings.
ITsPhone : an Integrated Platform for Participatory ITS Data Collection and Opportunistic Transfer
(IEEE, 2013) Briante, O.; Campolo, C.; Iera, A.; Molinaro, A.; Paratore, S. Y.; Ruggeri, G.; Booysen, Marthinus J.
The recent advances in sensing and communication technologies pave the way for interfacing cars with smartphones to offer value-added services to users on the road. Kinematics, automotive diagnostics, passengers load, and pollution data can be provided by vehicles, augmented with external sensors, to make the road transport greener and smarter. With the purpose of supporting and improving data collection and distribution, by boosting user participation, in this work a smartphone-based platform is demonstrated that exploits cheap dedicated hardware to interact with sensors on board and in the vehicle’s surroundings and opportunistically leverages available wireless connectivity to remotely transmit collected data.

Browsing by Author "Booysen, Marthinus J."

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