3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Predicting the effects of explosions placed on the earth's surface(2020) Grobbelaar, Michelle Robyn GarvinMany predictive equations within literature are focused on explosions within the ground such as mining blasts and tunnelling. According to the United States Code of Federal Regulations (30 CFR part 816.67 of 1998), the recommended equipment to monitor buried explosions, are geophones. Other equations which examine surface explosions utilise a number of specialised equipment in addition to the seismograph equipment used for monitoring buried explosions, such as microphones and pressure gauges. The aim of this study is to determine whether or not one could use predictive equations for buried explosions to predict the effects from surface explosions by merely using data obtained from a small network of surface installed seismograph stations. Military demolition sites are areas where old and potentially unstable explosives and obsolete equipment are destroyed and the ordnance is placed on the surface of the ground and detonated. The ordnance is seldom buried and thus modelling and predicting the ground vibrations and shock waves should consider predictive equations for both ground waves and atmospheric shock waves. The modelling can assist in preventing damages to surrounding infrastructure and injury to people in the vicinity. These equations could similarly be utilised for assisting in forensic seismology to determine the details of unexpected explosions, such as gas pipelines, silo explosions and vehicle bombs. By combining the various equations available, this study has identified a number of predictive equations which have produced acceptable results when examining data obtained from military ordnance demolitions on the surface. In general, the values for atmospheric shock waves are easier to determine than those from the ground motion because the atmospheric shock waves are more prominent on the seismograms than those of the ground motion, due to the fact that very little of the energy is transmitted into the ground. Therefore, utilising atmospheric shock wave measurements may be more useful because the ground motion waves are not clearly recorded. The study has shown that the USBM peak particle velocity (PPV) predictiveItem Assessing the impact of human behaviour on reservoir system performance using dynamic co-evolution(2019) Shanono, Nura JafarWater resource systems management entails the coordination of hydrologic, infrastructural and human activities to plan, develop and supply water efficiently and sustainably. Hydrologic and human behaviour involve high levels of uncertainty and therefore pose unique challenges to water management. In reservoir yield and operation analysis, hydrologic uncertainties are usually incorporated in risk analysis using stochastically generated data but the impacts of human behaviour, although significant, are typically not incorporated. This study was therefore inspired by the need to quantitatively incorporate the impact of human behaviour into reservoir system performance thereby adding value to reservoir operational decision making. Unauthorised water abstraction is a significant human behaviour‐related activity and was therefore selected for this study. A socio‐hydrological model that simulates, couples and dynamically co‐evolves reservoir operation and human behaviour to assess the impact of unauthorised water abstractions on reservoir yield and operation was developed. The model quantitatively and stochastically relates fourstate drivers; hydrological state, users’ compliance, management competence and reservoir performance. Users’ compliance and management competence were modelled statistically by a 3‐parameter skew‐normal distribution and the propensity to unauthorised water abstraction (risk perception) was modelled as a function of users’ compliance, management competence and the hydrological state. The occurrence of unauthorised water abstraction was modelled stochastically by relating a sigmoidal function of risk perception to management competence. To assess the impact of human behaviour, nine scenarios derived from the different combinations of 3 categories of users’ compliance and management competence were developed and tested. The model was applied at a monthly time step to 2 hypothetical but realistic reservoir systems that were based on 90 years of hydrology and configuration of the Elands and the Olifants River reservoir systems in South Africa. Reservoir operation for maximizing yield was optimized by applying a simulation‐optimization approach that used 3 reservoir operating rule curves defined using trigonometric and simple linear functions. Shuffled complex evolution (SCE‐UA) was used for optimisation. The SCE‐UA was effective for the optimisation of the two reservoir systems when simple linear operating rules were applied. When trigonometric rule curves were applied, the SCE‐UA optimized the Elands system effectively but repeatedly terminated at a local optimum with 35% less yield for the larger Olifants system. It was therefore decided to mainly use the results from the linear rule curves to assess the effect of human behaviour on the performance of the two systems. Realistic time series of unauthorised water abstractions whose severity increased as users’ compliance and management competence declined were obtained. The losses in average yield for varying combinations of users’ compliance and management competence ranged from 2.3 to 9.2% and 5.3 to 11.5% for the Elands and Olifants systems respectively. The overall average loss in yield for all the nine scenarios were 5.8% and 8.9% for the Elands and Olifants River systems respectively. The losses in yield in individual years, however, varied considerably and during the drought years of the 90 year simulation period, they were much higher than the average losses. In one year, a 55% reduction in yield resulted from the scenario with the most adverse human behaviour. Optimised reservoir operating rule curves became more restrictive and lower reservoir storage trajectories were obtained as human behaviour declined. The modelling, therefore, revealed that yield reduced as human behaviour deteriorated and the losses obtained were reasonably close to the reported annual water loss due to unlawful uses of 6.4% in South Africa. The sensitive nature of the subject of study makes model verification on real‐life systems challenging. However, the research shows that practical reservoir system modelling that quantitatively incorporate the impact of human behaviour is a future possibility.Item Leadership practices in two successful primary schools in Soweto, South Africa educating learners afflicted by multiple deprivation(2019) Hoosier, BrianettaThe study investigated the ways in which principals and other school leaders navigated issues of multiple deprivation to achieve high academic performance. The study was grounded in the theoretical framework of the University of Chicago Consortium on Chicago School Research (Bryk, Sebring, Allensworth, Easton, & Luppescu, 2010), which proposes five essential supports (5 Essentials) for successful schools. The framework was the lens used to understand whether or not successful school leaders implemented these five essentials supports in response to their learners’ battle with multiple deprivation. The main research question of the study is: what can we learn about school improvement from the leadership practices of successful school leaders in primary schools educating learners afflicted by multiple deprivation in Soweto? Interviews were conducted with two principals, three School Management Team (SMT) members, and three educators. Using thematic content analysis, recurrent themes emerged including stakeholders involvement, policy, academic support, progress monitoring, collaborative teachers, teacher quality, team building, parental involvement, and distributed leadership. In the South African context, this study expands the 5 Essentials framework through a contribution toward the emergence of a model of leadership practices of successful school leaders educating learners afflicted by multiple deprivation in primary township schools. In this model, the four core leadership practice with related themes, explain the leadership practices that underpin learner achievement. The core leadership practices and themes includes: (1) safety practices: stakeholder involvement and policy; (2) instructional practices: collaborative teachers; 3 (3) teacher quality and team building academic practices: academic support and progress monitoring; and (4) family engagement practices: parental Involvement (Biological or Proxy)Item Systems engineering in the research and development environment(2017) Ramdas, Ashlinuncertainties due to the unprecedented nature of the work undertaken. The system engineering approach has been utilized to deal with complexity and technical risks to reduce associated cost and schedule implications. The aim of this research is to investigate how the application of systems engineering reduces uncertainties and associated risks in the Research and Development environment? A case study approach was utilized and a research design was developed according to Yin (2009). The case utilized was the Square Kilometre Array Project as this project is done in an R&D context and applied systems engineering in the project. It was found that systems engineering does reduce technical risk and uncertainties in an R&D environment. This is achieved through the application of systems engineering technical processes and the utilization of technical management to plan the processes in line with the level of risk. Systems engineering methods and tools are then utilized in the process during project execution. Examples from the case are presented to support this finding. A limitation to this claim, due to the fact that not the entire R&D spectrum was investigated, is that the application of these must be tailored to the associated level of risk. The formality of the process must also be tailored to the level of risk and the size of the project team.Item Improvement of the software systems development life cycle of the credit scoring process at a financial institution through the application of systems engineering(2016-10-11) Meyer, NadiaThe research centred on improving the current software systems development life cycle (SDLC) of the credit scoring process at a financial institution based on systems engineering principles. The research sought ways to improve the current software SDLC in terms of cost, schedule and performance. This paper proposes an improved software SDLC that conforms to the principles of systems engineering. As decisioning has been automated in financial institutions, various processes are developed according to a software SDLC in order to ensure accuracy and validity thereof. This research can be applied to various processes within financial institutions where software development is conducted, verified and tested. A comparative analysis between the current software SDLC and a recommended SDLC was performed. Areas within the current SDLC that did not comply with systems engineering principles were identified. These inefficiencies were found during unit testing, functional testing and regression testing. An SDLC is proposed that conforms to systems engineering principles and is expected to reduce the current SDLC schedule by 20 per cent. Proposed changes include the sequence of processes within the SDLC, increasing test coverage by extracting data from the production environment, filtering and sampling data from the production environment, automating functional testing using mathematical algorithms, and creating a test pack for regression testing which adequately covers the software change.Item Towards identifiying the skills required for the changing role of the systems analyst(2015-02-17) Crossman, Trevor Douglas