This project investigated the implementation and evaluation of various collision-free path planning algorithms for the Saab Seaeye eM1-7 6-DOF Electric Manipulator (eManip). The primary goal was to enhance the autonomous performance of the eManip by integrating efficient path planning methodologies, ultimately ensuring the avoidance of collisions and manipulator singularities during underwater operations. Key algorithms examined included the Rapidly-exploring Random Trees (RRT) algorithm and its enhanced variants. Through simulation tests in MATLAB and Gazebo, metrics such as planning time, path length, and the number of explored nodes were evaluated. The results highlighted the robustness of Goal-biased and Bidirectional RRT* (Gb-Bd-RRT*), which consistently performed well across various environments. The research also highlighted the correlation between algorithm effectiveness and specific task attributes, emphasizing their adaptability to complex environments. This research contributes valuable insights into the effectiveness of path planning algorithms, informing the selection and integration of viable strategies for 6-DOF robotic manipulators.

This thesis is a study into the response and seismic safety of three-dimensional multi-storey concrete structures under concurrent orthogonal seismic excitations. It employs the nonlinear time-history method as its analysis tools. Time-history analyses rely heavily on their utilised earthquake records. Accordingly, this study examines the different approaches of selecting earthquake suites and develops a methodology of selecting representative earthquake scenarios. This methodology is credibly implemented in selecting a far- and a near field suites representative of the New Zealand seismic hazard. The study investigates the response of 6-, 9- and 12-storey concrete structures of different n-X-bays × m-Y-bays. Bidirectional responses of these considered structures are examined and consequently the current combination rules are scrutinised. Consequently this study strongly recommends the use of the 40-percent combination rule in lieu of the widely used 30-percent rule; and the use of time-history analysis in lieu of quasi/equivalent static and response modal analysis methods to avoid their strong dependence on combination rules. An intensive study is conducted employing the incremental dynamic analysis (IDA) technique to investigate structural demands of interstorey drifts, lateral storey drifts and storey accelerations. The study utilises the developed far-field suite and identifies the 50th and 90th percentile demands. Hence it provides easy-to-use expressions to facilitate rapid calculation of the structural demands and the effects of biaxial interactions. An implementation into the Demand and Capacity Factor Design (DCFD) format is presented that infers confidence in the performance levels of the considered structures. The study also draws attention to the importance of considering storey accelerations as their storey values reach as high as 10 × PGA. A sensitivity study is conducted by repeating the IDA investigation while using the developed near-field suite. Subsequently a comparison between the near- and the far-field results is conducted. The results were markedly similar albeit of less magnitudes until the (seismic hazard) intensity measure IM = Sa(T₁) = 0.4g when the near-field results show sudden flat large increase in demands suggesting a brittle collapse. This is attributed to the higher content of the higher mode frequencies contained in near-field ground motions. Finally, the study examines the (vectorial) radial horizontal shear demands in columns and beam-column joints of the previous far- and near-field studies. The combined radial shear demands in corner, edge and internal columns and joints are evaluated that roughly show a square-root proportional relationship with IM that exhibit somewhat brittle failure at IM ≥ 0.35g. Shears demands in the (4-way) internal columns and the (2-way) corner joints show highest magnitude in their respective class. The results suggest transverse joint shear reinforcement of 1.5, 1.0 and 0.5 of the longitudinal reinforcement of the neighbouring beam respectively for corner, edge and internal joints. An implementation of a proposed practical (and simpler) DCFD format shows satisfactory confidence in columns performance in shear up to IM = 0.35g, conversely to joints unsatisfactory performance in shear at the onset of inelastic behaviour (IM > 0.05g).

The thesis deals with the construction design of reversible swirl turbine used in a tidal range power plant for bidirectional operation. The theoretical part provides an overview of state-of-the-art technologies in the usage of tidal energy, mostly by means of tidal range and stream tidal power plants. It also analyses respective designs of tidal turbines and their advantages and disadvantages. The practical part of the thesis demonstrates individual steps applied when examining loading forces and also shows the design method and strength inspection procedure of the turbine and its parts, especially of the impeller, gears, shafts and bearings. Lastly, the paper outlines the selection approach of the most appropriate water plant generator.

Indiana University-Purdue University Indianapolis (IUPUI) / This thesis presents a converter topology for photovoltaic panels. This topology minimizes the number of switching devices used, thereby reducing power losses that arise from high frequency switching operations. The control strategy is implemented using a simple micro-controller that implements the proportional plus integral control. All the control loops are closed feedback loops hence minimizing error instantaneously and adjusting efficiently to system variations. The energy management between three components, namely, the photovoltaic panel, a battery and a DC link for a microgrid, is shown distributed over three modes. These modes are dependent on the irradiance from the sunlight. All three modes are simulated. The maximum power point tracking of the system plays a crucial role in this configuration, as it is one of the main challenges tackled by the control system. Various methods of MPPT are discussed, and the Perturb and Observe method is employed and is described in detail. Experimental results are shown for the maximum power point tracking of this system with a scaled down version of the panel's actual capability.

Text in English / Zimbabwe had 50 000 child-headed households (CHH) in 2002 and by 2010, the figure had gone up to more than 100 000, making Zimbabwe the African country with the highest number of CHH (UNICEF & UNAIDS 2010). These statistics gave rise to the sprouting of many organisations and programmes aimed at catering for the needs of the affected children. Not much attention is given to what the CHH can do for themselves and how they have be surviving without outside help. The present study explored the resilience factors and coping strategies used by children living in CHH in the Mutasa District, Zimbabwe. The mixed method concurrent triangulation design was used in the study and a constructionist theoretical framework was adopted. Semi-structured interviews and focus group discussions were used to collect data from 28 children in CHH, 46 community members, 24 teachers, 25 child service professionals, 10 advisory panel members, 3 government officials involved in policy formulation and implementation and 5 members of the CHH’s extended family. The Resilience Scale was administered to the CHH and the Tree of Life and problem solving activities were carried out with the children. Resilience scores obtained from the children in CHH were in the high to very high category of resilience. The qualitative data was thematically analysed. The research findings indicate that children in CHH use problem focused coping strategies. Their resilience is anchored in both individual and environmental factors. A Bidirectional Model of Resilience that is based on the findings emerged from the study.Three pathways to resilience that are embedded in this model were identified, furthermore the Self-Efficacy Strengths-Focused Model of Coping was proposed. Intervention strategies to foster resilience in CHH should focus on creating coping enabling environments and strengthening individual characteristics. / Psychology / Ph.D. (Psychology)

Zimbabwe had 50 000 child-headed households (CHH) in 2002 and by 2010, the figure had gone up to more than 100 000, making Zimbabwe the African country with the highest number of CHH (UNICEF & UNAIDS 2010). These statistics gave rise to the sprouting of many organisations and programmes aimed at catering for the needs of the affected children. Not much attention is given to what the CHH can do for themselves and how they have be surviving without outside help. The present study explored the resilience factors and coping strategies used by children living in CHH in the Mutasa District, Zimbabwe. The mixed method concurrent triangulation design was used in the study and a constructionist theoretical framework was adopted. Semi-structured interviews and focus group discussions were used to collect data from 28 children in CHH, 46 community members, 24 teachers, 25 child service professionals, 10 advisory panel members, 3 government officials involved in policy formulation and implementation and 5 members of the CHH’s extended family. The Resilience Scale was administered to the CHH and the Tree of Life and problem solving activities were carried out with the children. Resilience scores obtained from the children in CHH were in the high to very high category of resilience. The qualitative data was thematically analysed. The research findings indicate that children in CHH use problem focused coping strategies. Their resilience is anchored in both individual and environmental factors. A Bidirectional Model of Resilience that is based on the findings emerged from the study.Three pathways to resilience that are embedded in this model were identified, furthermore the Self-Efficacy Strengths-Focused Model of Coping was proposed. Intervention strategies to foster resilience in CHH should focus on creating coping enabling environments and strengthening individual characteristics. / Psychology / Ph.D. (Psychology)