Doctoral Degrees (Electrical and Electronic Engineering)

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Browsing Doctoral Degrees (Electrical and Electronic Engineering) by browse.metadata.advisor "Booysen, M. J."

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    Agent-based modelling of paratransit as an intelligent complex adaptive system to improve efficiency
    (Stellenbosch : Stellenbosch University, 2021-03) Ndibatya, Innocent; Booysen, M. J.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: Urban residents in Sub-Saharan Africa (SSA) face mobility challenges that limit theiraccess to jobs, services, markets, and socioeconomic opportunities. In most SSA cities,public transport is predominantly provided by the inefficient paratransit system – a flex-ible mode of passenger transport consisting of privately-owned, low-capacity unscheduledminibuses and motorcycle taxis. There is growing interest among city authorities andurban transport researchers in addressing the inefficiency problem associated with para-transit. Several approaches, such as complete overhaul to bus rapid transit (BRT), andphased banning of paratransit from the cities have previously been proposed and con-comitant implementation projects started. However, most of such projects have eitherfailed to take off, or they have stalled. This is likely because of the huge capital invest-ment required, the unique social and cultural dynamics associated with “third world”countries, and urban sprawl due to poor city planning. This study departs from the com-mon perspective held by several researchers and city authorities who view paratransit as“chaotic”, thus, the justification for its total overhaul and banning. Instead, this studyaims to leverage the beneficial aspects of existing paratransit – such as flexibility, demand-responsiveness and near-ubiquitous coverage – with the elusive objective of achieving amore efficient paratransit state as a result.Through theoretical modelling, field study and experimental approaches, this studyaimed to improve the efficiency of minibus taxis paratransit systems. The theoretical mod-elling work involved modelling paratransit systems as complex adaptive systems (CAS)and developing an agent-based model (ABM) for minibus taxi operations in an organically-evolved paratransit setting. The field study involved an in-depth investigation of minibustaxi operations in Kampala’s paratransit system, and collection and analysis of minibustaxi movement data that was used to validate the agent-based model. The experimen-tal approaches involved three separate simulation experiments, simulating the minibustaxi transportation dynamics with varying levels of agents’ intelligence and situational awareness. Machine learning methods, such as random forests and convolutional neuralnetworks were used to train agents in the subsequent simulation experiment to improvetheir intelligence during decision making. At each stage, several efficiency metrics’ valuessuch as passenger waiting time and minibus taxi occupancy were collected. The resultsfrom the experiments showed that there was an improvement in the overall efficiency ofthe minibus taxi paratransit system. For instance, the average passenger waiting time re-duced from 1.2 hours to 30 minutes, indicating a 55% improvement. Whereas the averageminibus taxi occupancy increased from 42% to 51%, indicating a 21% improvement. Ac-cordingly, we concluded that improving the micro-level agents’ intelligence and situationalawareness, results in an overall increase in the efficiency of the paratransit system.To the transportation researchers, we recommend further work on using ABM toinclude other modes of paratransit transport such as the three-wheeled rickshaws andmotorcycle taxis (boda bodas). To the city authorities, we recommend the integration ofsmart mobility and ICT applications into the paratransit ecosystem to support journeyplanning, booking, scheduling, and fare collection.
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    Smart dock for bicycle protection in theft-prone urban areas
    (Stellenbosch : Stellenbosch University, 2017-12) Swanepoel, Mardu Christof; Booysen, M. J.; Smit, W. J.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: Cycling, when utilised as a form of transport in an urban environment, holds valuable benefits and sustainable advantages for a wide variety of stakeholders. Various barriers exist that contribute to a low user adoption of cycling in an urban area, despite a high and growing user adoption of recreational cycling. Bicycle theft and inadequate bicycle storage facilities for on-street urban bicycle storage are amongst these barriers identified. In theft-prone urban areas, urban cyclists are hampered by the prevalence of theft when bicycles are temporarily secured during urban commuting trips. This can negatively affect an individual’s attitude towards urban cycling, and thereby increase the difficulty for regional authorities to draw from the advantages accompanying a high urban-cycling prevalence. This study proposes an on-street smart bicycle dock that is capable of adequately protecting a bicycle during an urban commuting stop-over, thereby aiding in the removal of the related barriers weighing against a higher user adoption of urban cycling. To ensure a successful and sustainable solution, three important stakeholders were considered in order to incorporate their requirements and behaviour into the solution. Bicycle thieves were interviewed and studied to understand the methods and motives involved in urban bicycle theft, active cyclists were investigated through questionnaires to understand their requirements and attitude towards a potential solution, while a local municipal and academic institution involved in the potential implementation of the solution were engaged with to understand and incorporate their needs and requirements. A conceptual solution that serves as the research model was produced by turning the relevant insights obtained from the research activities into product design specifications that served as a quantitative template to guide the development of the conceptual solution. The resulting solution was broken up into four functional areas that were developed separately but dependent on each other, after which they were combined to collectively form the final solution. The first solution area sees the development of a mechanical steel frame that secures a bicycle docked in the system, by physically locking its wheels and frame using a novel locking method. This frame protects the bicycle’s critical components against the majority of tools and methods commonly used in bicycle theft, and was found to provide better protection than existing solutions, accept against theft using a hacksaw where only 71% of the required protection was provided. The second area sees the development of a sensing system that uses force transducers situated below the bicycle, to convert any disturbance on the bicycle into a digital time-discrete signal that is processed by a signal processing algorithm developed, in order to detect any attempt of theft performed on the docked bicycle. The sensing system obtained a false-negative rate of 8%, a detection duration of 8.6 seconds, and a false-positive rate of 15%. The third area sees the development of a locking mechanism that engages and disengages the mechanical frame’s protection in 1.4 seconds, in a way that is universally accessible to different users without them requiring a physical method of access. The lock obtained a locking reliability of 96%. The fourth area sees the development and implementation of system elements that are responsible for the system’s integration and general control, including a system state machine, user interface, cloud platform, and communication capabilities with accompanying communication protocol for the various system elements. The resulting solution’s performance was measured through five tests aimed at addressing different performance areas of the solution. The overall performance of the model is determined as satisfactory, with it meeting the majority of the initial requirements and specifications defined, and thereby successfully addressing the problem statement relevant to this research.