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Research Commons is the University of Waikato's open access research repository, housing research publications and theses produced by the University's staff and students.
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Publication Heritage buildings and community sense of place(Conference Contribution, New Zealand Society for Earthquake Engineering (NZSEE), 2024)New Zealand is a nation that has a significant amount of built heritage, of which there are several internationally recognised landmarks, including the Christchurch Cathedral, the Church of the Good Shepherd, and the Chateau Tongariro. These structures contribute to establishing a sense of place within a community as landmarks, gathering places, and keepers of memories and personal sentiments. Unfortunately, due to New Zealand’s recent and historic seismic activity, these landmarks, commonly constructed as unreinforced concrete or masonry, are susceptible to severe damage from earthquake-induced ground shaking. For this reason, the New Zealand government introduced the Building (Earthquake-prone Buildings) Amendment Act 2016, which presented stricter seismic strengthening regulations for vulnerable buildings (earthquake-prone buildings) to ensure better life safety outcomes for such structures. The associated costs and challenges of retrofitting heritage buildings have put many of these structures at risk of abandonment or demolition, taking their embodied heritage value with them. This research uses survey data to establish how heritage buildings develop a sense of place within a community and how the public’s perception can implicate preserving heritage buildings. Survey results indicated that people value these structures in their communities. Further, personal connections to heritage buildings or knowledge of the historical context improve the desire to preserve and restore these structures.Publication A supercapacitor assisted technique for reducing losses in the input loop of an inverter system for solar PV applications(Conference Contribution, IEEE, 2024)This paper presents a method of using supercapacitor modules in the input loop, to reduce the input losses of a typical inverter system used in solar applications. It is an extension of the supercapacitor-assisted loss management principle (SCALoM), where supercapacitors act as lossless droppers and energy buffers at the input end with a very low frequency switching scheme with reduced dynamic losses in switches compared to switched capacitor-inverter systems. The technique uses a set of micro-inverters, with the same total power capability as a single inverter, combined with a set of supercapacitor banks switching at a low frequency to reduce the voltage stress and rms current through the H-bridge input stages of the inverters, enhancing the end-to-end efficiency of the overall system. The proposed technique does not require a re-design of the commercially available inverters and adds DC-UPS capability to the system. Preliminary experimental results of the SCA(super capacitor assisted) two-inverter arrangement show stable transient and steady state operations, and the system is up to 2.2% efficient compared to a single central inverter arrangement. With the proposed SCA four-inverter configuration, inverter's overall power load can be further partitioned, and according to the analytical study further improvements in the overall efficiency can be achieved over the SCA two-inverter arrangement.Publication Preliminary experiments quantifying the arcing process in a DC circuit breaker development project(Conference Contribution, Institute of Electrical and Electronics Engineers, 2024)AC circuit breakers are well-established technology today. However, DC circuit breakers (DCCB) are not easy to design and build since there are no zero crossings in a DC power supply. Mechanical and semiconductor switches are the key elements considered under various circuit topologies to design DCCBs. However, mass-produced commercial DCCBs are designed by modifying AC breakers by connecting multiple poles in series and/or using permanent magnets inside the breaker to lower the cost of DCCBs except for special applications such as in the military industry. Some of the major issues behind the DCCB design are fundamentally explained in this research with simple experimental results based on DC arc characteristics. We intend using these experimental observations in a new design approach for DC circuit breakers using supercapacitor energy absorption.Publication Using model trees for classification(Journal Article, Kluwer Academic Publishers, 1998)Model trees, which are a type of decision tree with linear regression functions at the leaves, form the basis of a recent successful technique for predicting continuous numeric values. They can be applied to classification problems by employing a standard method of transforming a classification problem into a problem of function approximation. Surprisingly, using this simple transformation the model tree inducer M5′, based on Quinlan’s M5, generates more accurate classifiers than the state-of-the-art decision tree learner C5.0, particularly when most of the attributes are numeric.Publication Animating traumatic memory in documentary(Conference Contribution, AUT University, 2024-07-07)
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