Masters Degree Theses

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Distributed agent-centric system for indigenous data sovereignty
(Thesis, The University of Waikato, 2024) Noovao, Setephano
The sovereignty of indigenous data is a key issue facing indigenous communities. Holochain, a distributed ledger technology, has the potential to address some of the challenges indigenous communities face with respect to data sovereignty. The purpose of this thesis is to critically evaluate the feasibility of using holochain technology to support indigenous data sovereignty. This paper first explores the literature on holochain technology, examining its underlying architecture and features. The research employs a three-phase design science research methodology, conducting an experiment to explore the integration of a decentralized application, holochain, with a prominent cloud service provider. The first phase concentrates on emulating real data-sharing platforms that may utilize data at its disposal, following the principles of indigenous data sovereignty, where a centralized platform could be hosted on a cloud computing service with multiple services in operation. The second phase involves developing a holochain application guided by the principles of indigenous data sovereignty. The final phase seeks to combine the established centralized platform from the first phase with the outcomes of the holochain application from the second phase to experimentally assess whether both technologies can create a data sovereignty solution that aligns with the needs of indigenous data sovereignty. The results of the experiment will provide a solid foundation for understanding the current state of the field and identifying areas where holochain can potentially offer solutions. Furthermore, the results of our research indicate that holochain shows significant promise in tackling the issue of indigenous data sovereignty, although there are considerable limitations that must be addressed and resolved to achieve improved results.
He whiringa aroha: A mokopuna and a pare in the peabody essex museum
(Thesis, The University of Waikato, 2024) Murray, Moana
Taonga, Māori ancestral treasures, embody the mana and knowledge of Māori ancestors. He Whiringa Aroha is one such treasure: a carved pare that affirms the mana of wāhine in the colonial archives, but whose whakapapa has been obscured. This thesis uses the name ‘He Whiringa Aroha’ and the te reo Māori pronoun ‘ia’ to refer to ‘E5501’, which is located in the 1806 Richardson collection in the Peabody Essex Museum. As He Whiringa Aroha travelled from Aotearoa New Zealand to Massachusetts, United States, ia became entangled in historical narratives that disembodied the taonga from hapū and iwi Māori. Taonga were not only physically removed from Aotearoa, but taonga and Māori creative practices were named, gendered, and displayed by colonisers. American sailors collected and displayed He Whiringa Aroha as an exotic ‘curiosity’ to showcase their triumph over Pacific waters. Yet, He Whiringa Aroha is a power portal—a potent braid to the past, the future, and to those Māori ways of being that defy the limiting archival language of colonialism. How do we relate to taonga Māori that have been fragmented by the colonial archive? What are alternatives to restory and reclaim taonga that remain in overseas museums? Using a creative methodology grounded in Mana Wahine and pūrākau, this thesis weaves a whiri (braid) of aroha (reverence) that attempts to restore he hononga mokopuna–the connection between taonga and their descendants. Through poetry, a decolonial map, interviews with ringatoi (Māori creatives), and archival research, I explore how the histories of taonga can be reclaimed in Māori worldviews. Interviews with pūkenga and tohunga toi reveal Māori understandings of taonga as expressions of toi, defying western taxonomies of ‘art’ and ‘curio’. Furthermore, archival research into the East India Marine Society and Peabody Essex Museum unmasks the American sailors and their provenance practices that have marginalised Māori, and in particular, wāhine Māori. Finally, I use pūrākau of atua wāhine, Mana Wahine and takatāpui scholarship to restory and rename He Whiringa Aroha. This archival storytelling raises new ethical questions about ownership and kaitiakitanga (guardianship), which pose interventions for existing conversations about the place of taonga Māori in overseas museum collections. Reclaiming the histories of ancestors in museums is more than decolonizing colonial archives; on the contrary, restorying taonga is an act of Indigenous resurgence. This Masters research opens new possibilities to reclaiming takatāpui narratives and the mana of wahine in museum archives.
A quantitative investigation into the effectiveness of a 2x2, crossover, randomized control trial, for individuals suffering from non-specific chronic lower back pain, using a physical exercise-focused clinical intervention on the transverse abdominus/ multifidus (stability) and rectus abdominals/ erector spinae (dynamic) muscles.
(Thesis, The University of Waikato, 2024) Callaghan, Adam James
A plethora of research has been conducted on interventions to reduce non-specific lower back pain and improve the quality of life of sufferers. However, there is a lack of distinction on the complementary nature of these interventions. Our primary research goal was to assess the effectiveness of stability- and dynamic-style clinical interventions, focusing on exercises to strengthen specific trunk muscles, including the transverse abdominis/multifidus (stability-AB), and rectus abdominis/ erector spinae (dynamic). We aimed to determine the effectiveness of these interventions in reducing non-specific chronic lower back pain. Our research questions focused on whether a two-part clinical intervention targeting specific core muscle groups (dynamic or stability) improves pain outcomes, whether exercises targeting specific core muscle groups improve disability index physical impairment and overall low back pain rating scale scores, and if there is a difference between intervention groups and the sequential order of intervention for these outcomes. Additionally, we wanted to investigate the correlation between these outcome measures and trunk endurance strength scores. Seven participants were randomly assigned to either the stability (N =4) or dynamic (N = 3) exercise group. Outcome measures included back and leg pain, lower back pain visual analogue scale scores, disability index, physical impairment, and total Low Back Pain Rating Scale (LBPRS) scores. Four measures of trunk endurance strength were taken using Mcgill's Torso Endurance Test Battery (MTETB), which involves trunk extension, trunk flexor, and trunk lateral tests on both the left and right sides. Assessments were performed before the first clinical intervention, after the first intervention, and after the completion of the final intervention. Each intervention phase lasted 4 weeks for each participant before they switched to the opposing exercise group. The scores of back and leg pain, lower back pain, disability index, and physical impairment all improved significantly after both interventions. We found no difference between the groups during these intervention phases, or any potential crossover/sequential effect, except for the dynamic group showing a significant improvement in physical impairment scores after the first intervention, which remained consistent between interventions one and two. In conclusion, both exercise approaches were similar across all our outcome measures and may serve as complementary interventions for individuals suffering from non-specific chronic low back pain.
Examining neuroplasticity as a function of errors during motor learning
(Thesis, The University of Waikato, 2025) Nirol
Proficient motor learning is important for both athletes looking to improve their performance and patients learning daily living skills. Research has identified different methods for learning motor skills, focusing on two types: implicit and explicit learning. Implicit learning happens with little awareness, while explicit learning requires more conscious thought. Studies show that implicit learning is often more effective because it uses less mental effort and is more reliable under stress. This might be due to stronger neural connections in the brain formed during implicit learning. However, it is unclear whether implicit learning leads to more brain changes, known as neuroplasticity, than explicit learning. Neuroplasticity is the brain's ability to adapt and form new memory networks in response to experiences. This study aims to investigate differences in neuroplastic changes resulting from implicit versus explicit learning of a traditional Dutch shuffleboard game (Sjoelbak). We used baseline electroencephalography (EEG) to measure changes in brain activity before and after practice to assess neuroplasticity. We examined the effects of errorless and errorful learning protocols on task performance and neural connectivity. Both strategies improved accuracy from pretest to posttest, indicating effective skill acquisition. However, participants struggled to transfer skills to new contexts, as shown by decreased performance in the transfer test. Despite expectations of greater neuroplastic changes as a function of errorless learning, resting-state beta connectivity analyses showed no significant interactions. However, no significant differences were evident in the overall error rates between the groups during the learning phase, suggesting that implicit motor learning may not have occurred for the errorless learning condition. This suggests that neural adaptations are more complex than initially hypothesized.
Network analysis of mindfulness and mental health symptoms among firefighters: A transdiagnostic lens
(Thesis, The University of Waikato, 2024) Yan, Vivienne
Previous research has established the protective role of mindfulness against various psychological disorders and maladaptive behaviours. However, the associations between specific facets of mindfulness and diverse mental health and behavioural outcomes have not been thoroughly investigated in populations with risky occupations. The aim of this study was to examine the direct and indirect associations between the five facets of mindfulness and prevalent mental health and behavioural outcomes among firefighters, including depression, post-traumatic stress disorder (PTSD), anger, suicide risk, sleep quality, and alcohol use. The assessment scores of 685 career firefighters (Mage=38.40, SD=8.64; 93.6% males; 77.7% White) including 154 (22.5%) military veterans, who completed measures of mindfulness, depression, PTSD, anger, suicide risk, sleep quality, and alcohol use, were investigated using both directional and non-directional network analysis. Directional network analysis indicated the primary role of anger in triggering PTSD and impacting mindfulness, leading to alcohol use, suicidal ideation, impaired sleep quality, and depression as an outcome. Mindfulness facets of Non-reactivity, Non-judging, and Describing were negatively associated with depression, while the Acting with awareness facet was inversely linked to anger. This study emphasizes the clinical significance of targeting specific mindfulness facets in interventions for high-risk occupations, such as firefighters. Focusing on Non-reactivity, Non-judging, Describing, and Acting with awareness may help mitigate anger, depression, and other negative outcomes. Addressing anger management could be especially important in preventing or reducing PTSD, alcohol use, suicidal ideation, sleep disturbances, and depression, ultimately enhancing psychological well-being and quality of life.
Monitoring te mana o te wai: Intergrating an indigenous cultural health index with conventional biomonitoring tools for improved freshwater management
(Thesis, The University of Waikato, 2024) Edgecombe, Shana Jade Te Iaa Tarere
Globally, there are universal efforts to quantify and address human impacts on ecosystems. In particular, changes in land use and river regulation have led to drastic declines in stream and river ecosystem health. These human impacts are driving the global freshwater biodiversity crisis and degrade ecosystem services provided by aquatic habitats. In Aotearoa New Zealand there is widespread concern about the state of our Nation’s freshwater ecosystems. Coupled with a renaissance in Māori culture, there has been a drive to develop indicators that help articulate cultural values, assess ecosystem health from a cultural perspective, and provide greater agency for Māori in environmental monitoring and management. In my thesis, I sought to integrate an established cultural monitoring framework with conventional biomonitoring tools for improved freshwater management. I hypothesized that using a suite of monitoring approaches would help detect the impacts of human land use on stream ecosystem health, and that cultural indicators would be consistent with conventional measures in diagnosing land use impacts. I also hypothesized that there could be discrepancies between cultural monitoring and conventional approaches, as each represent different perspectives and ways of knowing streams and rivers. To test my hypotheses, I selected ten stream sites across the catchment of the Kuratau River, a major tributary of Lake Taupō. Based on River Environment Classification land cover types, I used a balanced study design with five sites draining indigenous forest, and five sites draining pastoral land. I measured key stream physicochemical properties and collected water samples for determination of nutrient concentration and faecal coliform counts. I also characterised instream and riparian habitat. I collected benthic macroinvertebrate samples and sampled water for environmental DNA (eDNA) to assess different facets of biodiversity. I measured decomposition using the Cotton Strip Assay and quantified periphyton biomass using a portable fluorometer. In combination with these approaches, I also used a Cultural Health Index, an established cultural monitoring framework that assesses three components: customary significance, taonga species/mahinga kai (food gathering), and the Cultural Stream Health Measure (CSHM) to assess identified attributes for stream health. I found that pastoral land uses lead to a decline in stream ecosystem health when compared to sites draining indigenous forest. Pastoral sites had higher specific conductivity and concentrations of total nitrogen and nitrate. Habitat variables changed, with increased sedimentation and more degraded riparian zones in pastoral streams. Decomposition rates as measured by the cotton strip assay increased in the pasture sites, which was likely a response to increased nutrient availability. There were shifts in macroinvertebrate composition, with key indicator taxa for Indigenous forest sites including pollution-sensitive mayflies and stoneflies. Total taxa, EPT (Ephemeroptera, Plecoptera, Trichoptera), and aquatic insect richness all significantly declined in pastoral sites. Increases in primary production were less pronounced, but did increase alongside abundances of grazing caddisflies and snails in the sites draining pastoral catchments. The Cultural Health Index indicated that sites in the Kuratau River catchment had customary and mahinga kai values. CSHM responded negatively to pastoral land uses, and the effect size it described was congruent with other responses. The CSHM was strongly correlated with an indicator of riparian habitat condition (the Riparian Condition Index) and had weak negative correlations with sedimentation and stream temperatures. The CSHM was not correlated with macroinvertebrate indices, which may have been because of the relatively few sites sampled, the narrow impact gradient in the Kuratau catchment, and the lack of temporal replication. However, cultural monitoring approaches should be seen to complement conventional environmental monitoring methods for assessing freshwater and not be expected to duplicate them. The strength of the Cultural Health Index approach comes from establishing Māori agency to assess the environment through a Te Ao Māori lens, and to support and foster inclusion for tangata whenua epistemologies in environmental monitoring and resource management. Future research should consider greater hapū involvement and further explore the mechanisms driving changes in stream health and biodiversity.
Influence of ageing heating rates on the microstructure and mechanical properties of Ti-5553 alloy
(Thesis, The University of Waikato, 2024-09-15) Jia, Mengqi
The Ti-5553 alloy, a high-strength β-titanium alloy, is increasingly recognised for its exceptional mechanical properties, making it a preferred material for critical aerospace applications. This thesis examines the effects of varying ageing heating rates on the microstructure and mechanical properties of the forged Ti-5553 alloy, focusing on hardness, tensile properties, and fatigue performance. Following solution treatment at 810°C, the alloy was aged at 610°C with heating rates of 1°C/min, 5°C/min, 10°C/min, and 15°C/min. Detailed microstructural analysis was conducted using Scanning Electron Microscopy (SEM) and Energy Dispersive X ray Spectroscopy (EDX). The microstructural examination revealed that different ageing heating rates caused only minor variations in the alloy's bimodal microstructure. Slower ageing heating rates produced a relatively fine, homogeneously distributed primary α phase within the β grains, while faster rates resulted in a slightly coarser bimodal microstructure. Chemical homogeneity analysis confirmed a consistent distribution of critical elements, with α stabilisers concentrated in the primary α phase and β stabilisers in the β phase, ensuring stable phase compositions across all samples. The observed slight microstructural changes were reflected in the alloy's mechanical properties. Hardness across different ageing heating rates varied between 357.4 HV and 372.6 HV. The ultimate tensile strength (UTS) declined from 1307.2 MPa at 1°C/min to 1264.5 MPa at 15°C/min, while ductility improved from 15.6% to 17.1% over the same range. The alloy demonstrated good fatigue resistance at lower stress amplitudes and ageing heating rates, enduring over 10 million cycles at 337.5 MPa under the 1°C/min condition. However, fatigue life decreased with higher stress amplitudes and ageing heating rates, highlighting the alloy's sensitivity to more extreme conditions. In summary, while the varying ageing heating rates resulted in only minor changes to the microstructure, these alterations had some impact on the mechanical properties of the Ti-5553 alloy. These findings highlight the importance of precise microstructural control in optimising the alloy's performance, especially in applications where achieving a balance between strength, ductility, and fatigue resistance is crucial.
Row-column block designs: Efficiency and structure
(Thesis, The University of Waikato, 2024-09-23) Nie, Xiao
A row-column design is any rearrangement of the blocks of a combinatorial design into a rectangular array. A row-column block design is a row-column design in which the blocks form a balanced incomplete block design; that is, each pair of elements occurs in a constant number of blocks. In this thesis we study the efficiency and structure of row-column block designs. In particular, we use solutions to Heffter’s difference problem to give construct row-column block designs with 3 elements per cell with optimal regularity in rows and columns. In Section 1 we review definitions and theorems related to Latin squares. We introduce related concepts of balanced incomplete block designs and incidence matrix and concurrence matrix of designs. In Section 2 we give our main results of row-column block designs with block size 3. In Section 3 we use Heffter’s difference problem to give some solutions. In Section 4 we explain efficiency measures for block designs. In Section 5 we introduce Trojan semi-Latin squares. We give efficiency measures for Trojan semi-Latin squares. In Section 6 we show the applications to experimental design. Original results are given in the following theorems: Theorem 2.9, Theorem 3.1, Theorem 3.3, Theorem 3.4, Theorem 4.2, Theorem 5.2, Theorem 5.12. Results from Section 2 and Section 3 have been submitted as a manuscript for publication [17] (Xiao Nie, Row-column block designs with blocks of size three, Ars Combinatoria, submitted).
Navigating the noise: evaluating the occurence of vessels and cetaceans within tamatea/dusky sound
(Thesis, The University of Waikato, 2024) Bassett, Oliver
Vessel use associated with recreation and tourism is currently increasing without limits in Dusky Sound. Passive acoustic monitoring was used to investigate spatiotemporal presence and potential cooccurrence of vessels with the endangered resident subpopulation of Fiordland bottlenose dolphins (Tursiops truncatus) and migratory humpback whales (Megaptera novaeangliae) within Tamatea/Dusky Sound, Fiordland Marine Area (FMA). Hydrophones were deployed between February 2022 and November 2023 at three recording sites to collect soundscape data within Dusky Sound. The internal coastline of Five Fingers Peninsula, inside Taumoana Marine Reserve, was identified as a previously unrecognised area of significant usage for Fiordland bottlenose dolphins. Detected humpback whale presence coincided with peaks in migration, and though identified by previous visual surveying efforts, the extent of their presence in the area during their northward migration was previously unreported. Humpback whale presence was significantly higher in June compared with other months, which is consistent with their described increased vocalisation behaviour during the northward migration. Vessel presence detected by passive acoustic monitoring was primarily dictated by usage patterns of tourism and recreational vessels and was greatest in the channel south of Anchor Island, a highly utilised access into Dusky Sound from the outer coast. Monthly equivalent continuous sound levels (LEqs), produced using Automatic Identification System vessel records and sound propagation modelling, illustrated that sound exposure levels regularly reached ~150 dB re 1 µPa2.s within the study area. Cruise ship transits were the major contributor to these high levels, with noise levels exceeding the recommended behavioural exposure threshold for continuous sound in much of the area during the late spring and summer months. Proactive management strategies including vessel limits, speed restrictions (slowdowns) and exclusion zones (dolphin protection zones) are likely required in the future to protect these species before the potential impacts from increased tourism is seen in Tamatea/Dusky Sound.
Automated capture/replay test generation for android using espresso
(Thesis, The University of Waikato, 2024-11-25) Alblooshy, Fajer
This thesis presents the design of a new tool for automated test generation in Android applications using the Espresso framework. The primary focus is on designing a robust and efficient tool with the use of the Presentation Model (PModels) to simplify the automation of test case design. By incorporating techniques such as interaction sequence modeling and widget-based abstraction, the tool’s design aims to address the challenges of testing interactive systems, which are often timeconsuming and complex. The research includes comprehensively analyzing existing testing methodologies, identifying their limitations, and proposing enhancements to improve test coverage and reliability. Through detailed design documentation and conceptual frameworks, the study demonstrates how the tool can generate maintainable test scripts, reducing the effect required for manual testing. The tool’s design is evaluated through theoretical case studies, including various Android applications, to illustrate its potential effectiveness in real-world scenarios. This work contributes to the field of software engineering by offering an approach to automated UI testing, emphasizing the importance of design considerations in developing tools that can meet the evolving demands of software quality assurance.
Optimisation of eDNA replication and detection distance in Aotearoa New Zealand lotic systems
(Thesis, The University of Waikato, 2024) Smith, Joshua
The use of environmental DNA (eDNA) is a relatively new tool in New Zealand, and its increased use worldwide in the last decade has seen a surge in its utility and application. The information gaps in its use and effectiveness in the field of environmental science are fast being explored and answered. However, many questions remain unanswered, particularly in an Aotearoa New Zealand context. The aim of this thesis is to extend the knowledge needed for effective and efficient use of this new and exciting tool in lotic Aotearoa New Zealand conditions. National standardisation of ecological sampling protocols between different agencies in Aotearoa New Zealand has historically been difficult to attain, creating challenges for combining datasets for national scale analyses. The introduction of new methods for biological monitoring, such as environmental DNA (eDNA), presents an opportunity to standardise aquatic sampling protocols prior to widespread adoption. The objective of this study (chapter two) was to optimise eDNA sample replication for the consistent characterisation of freshwater fish and macroinvertebrate communities in flowing waters, and ultimately, to inform the development of robust national monitoring standards. A comparison of field replication and extraction methods (pooling of preservation buffer) was also trialled as part of this high replication (n=16) eDNA study to assess any potential benefits in measuring species richness and reducing processing costs alongside replication optimisation. This involved two ‘syringe’ sampling methods (‘standard’ and ‘boosted’, eight each) conducted across 54 riverine sites throughout the country. No significant difference was found for species richness between the standardised (eight replicates) or boosted (16 replicates composited to eight) eDNA methods for fish and macroinvertebrates. Results indicated that six replicates were needed to consistently detect 89.5% of fish species likely to be present using field-based syringe eDNA sampling and preservation. However, an altitudinal species richness effect was observed for fish. For macroinvertebrates, six replicates were required to identify 86% of taxa identified to the NEMS (National Environmental Monitoring Standards) level used for the Macroinvertebrate Community Index (MCI: usually genera) while eight replicates were required to detect 89% of NEMS taxa. For fish and macroinvertebrate biodiversity, this study suggests that six replicates are a reasonable trade-off between effective community characterisation and cost in Aotearoa New Zealand lotic systems. Understanding the spatial limits and the way in which eDNA behaves in lotic systems is important to understand when designing eDNA sampling programmes and interpreting results. Questions around biodiversity detection at spatiotemporal scales in relation to stream order and the influence of tributaries remain. We sought to extend our knowledge of longitudinal eDNA dispersal and detectability in wadable lotic systems by using live caged fish and a naturally occurring habitat specific fish species. An additional unexpected external molecular source was also included in the analysis. An eDNA collection method comparison between active and passive sampling techniques was also trialled alongside caged experiments in the second half of this study. A correlation between stream discharge and the distance in which eDNA travels downstream is reported. An initial drop in eDNA concentration from caged fish over the first kilometre downstream is followed by a peak 4 km downstream, is suggested to be reflective of plume dynamics. Tributary-specific fish species at low biomass and their associated eDNA signal is largely diluted and not detectable directly downstream of confluences, though there was some evidence that if sampled further downstream in the mainstem, tributary signals may be detected. The caged fish trials showed how far an eDNA signal can travel, while results from naturally occurring longitudinal signals confirm that eDNA metabarcoding can measure biodiversity at spatiotemporal scales. Active sampling in general outperformed passive sampling. Issues around field contamination and sampling strategies based on results from this study are also discussed. Overall, this thesis provides insights and potential guidance in the use of eDNA in lotic Aotearoa New Zealand systems. It highlights the importance of eDNA field replication in the measurement of biodiversity for fish and macroinvertebrates and some terrestrial species. It helps interpret the ecology of eDNA in distance and structure. This information may assist in future eDNA sampling strategies and monitoring.
Monitoring of local topographic variation in flowering phenology of mānuka (Leptospermum scoparium)
(Thesis, The University of Waikato, 2024) Towgood, Eric
The rise of the mānuka honey industry has led to a change in attitudes toward mānuka (Leptospermum scoparium). Previously considered a nuisance for pastoral hill-country farming, mānuka stands are now more likely to be considered a valuable resource. For better management and utilization of this resource, more information is needed about the causes of variation in the timing and intensity of mānuka flowering, including at the local scale where flowering behaviour can vary significantly over short distances. Therefore, the first aim of this thesis was to improve methods for camera-based monitoring of mānuka flowering phenology, including reducing the need for manual analysis of images. The second aim was to deploy the cameras for a field study of the local-scale drivers of mānuka flowering phenology, within a single hill-country property, along an elevational gradient and between two slope aspects. This study used cameras based on Raspberry Pi single board computers, developed previously for monitoring of mā
An improved and robust finite element model for simulation of cold-formed steel built-up beams
(Thesis, The University of Waikato, 2024) Birwadkar, Harsh Hemant
Cold-formed steel (CFS) built-up sections are increasingly utilized in structural applications due to their lightweight properties, high strength-to-weight ratio, and enhanced moment capacity, which can be further improved by adding stiffeners to the webs or flanges. Accurately determining the moment capacity of these sections is important for practical use. This can be achieved through experimental testing or finite element analysis (FEA) using a four-point bending setup. However, conducting full-scale experimental tests is both expensive and time-consuming, and developing a full-scale finite element (FE) model to replicate these tests can be computationally intensive. To address these challenges, this study introduces an accurate, efficient, and robust numerical method that replicates the behaviour of CFS built-up sections, applicable to both back-to-back and face-to-face configurations. The proposed numerical methodology demonstrates excellent agreement with available test results in terms of moment capacity and failure modes, highlighting its potential for determining the moment capacity of built-up sections. The study further investigates two cross-sectional types—stiffened nested and unstiffened nested—to evaluate their behaviour and moment capacity. The proposed simplified model was subsequently used in an extensive parametric study to determine the moment capacity of stiffened and unstiffened nested sections. Parameters considered in the study include varying section thicknesses (0.75 mm to 3.00 mm), web depths (150 mm to 600 mm), section configurations (nested and stiffened nested), and screw spacings (75 mm, 150 mm, and 300 mm). Given that existing design standards, such as those from the American Iron and Steel Institute (AISI 2016) and the Australian/New Zealand Standards (AS/NZS 2018), lack specific guidelines for calculating the moment capacity of these sections, this research aims to fill that gap. Furthermore, to simulate practical scenarios, models incorporating screws in the webs (screw-web model) were developed and compared against the simplified model. The results of the parametric study revealed that the moment capacity of the built-up sections is significantly influenced by section thickness, web depth, and section configuration. Screw spacing, however, had a less significant impact. Notably, the moment capacity of the screw-web model was lower than that of the simplified model, emphasizing the importance of bimoment and warping deformation in connection design. The study concludes that the developed simplified model provides a computationally efficient tool for predicting the moment capacity of built-up beams, offering valuable insights for designers and engineers. Additionally, the nested section configuration is recommended for achieving higher moment capacity compared to the stiffened nested section.
Cultivating microbial dark matter - A combination of traditional and molecular techniques
(Thesis, The University of Waikato, 2024) King, Charlotte
The services bacteria offer the world are immense and impact people's lives daily. They were first described by Antoni van Leeuwenhoek in 1676, but bacteria have been utilised in the medical, agricultural, and food and beverage industries even before they were formally identified. Microbes’ roles in the environment for cycling of nutrients, climate regulation and pollution are becoming more well understood, and they are also utilised to answer a wide variety of research questions in disparate fields. Traditional cultivation techniques were initially developed to study bacteria and understand their functions as isolates. Such cultivation techniques have become rarer as new molecular and bioinformatic tools have been developed. These cultivation- independent techniques have allowed the study of microbial life genetic data which led to the finding that 99% of all microbial species were yet to be cultured and studied in a laboratory. The applications of these unstudied organisms could be unprecedented, though their cultivation remains challenging due to the requirement of specific nutrients that are hard to identify, very slow growth rates, environmental conditions that are difficult to replicate in a laboratory setting, live in symbiosis with other organisms, or live in extreme climates. Therefore, much of the information may be overlooked and hidden in this microbial dark matter. Methods such as metagenomics, metagenome-assembled genomes (MAGs), and single amplified genomes (SAGs) have provided us with genomic data for previously uncharacterised microbes from diverse environments. However, such data is still limited. Omics tools can provide insights into what is living there and what it can potentially do. However, this data is regularly incomplete due to the processes involved in sequencing, and conclusions are often drawn from associations relating to cultured organisms. This can lead to potentially spurious conclusions as a gene may behave differently in different species, and the absence of genes may depend on how the data was analysed. Therefore, cultured isolates of the organism are vital. To combat this issue of an uncultivated majority, it is important to have a targeted approach to culture, what is wanted, not just what is easy. This thesis aimed to provide an easy-to-follow, straightforward workflow to cultivate target environmental organisms using standard molecular tools and methods readily accessible in any standard microbiological laboratory. The idea is to isolate and culture what is specifically wanted or needed, not just what is easy. Specifically, it combined classical cultivation and molecular techniques to target a sulphur-reducing, obligate anaerobe from an environmental sample— namely a Desulfurella sp. from a geothermal pool in Rotorua, New Zealand. In order to provide the desired targeted approach, specific primers needed to be designed and assessed to first find the right sampling site for the initial inoculum and second to ensure the target is not lost throughout the culturing process. I designed and evaluated primers for targeting specific taxa at different stringency levels. Initially, I tested published primers (EPS_F/EPS_R, Gittel et al., 2012) aimed at Epsilonproteobacteria, which were reclassified into the Campylobacterota phylum (including Desulfurella sp.). These primers did not target Desulfurella sp., so I modified them (EPS_FM/EPS_RL) to produce a longer amplicon for broader Campylobacterota detection. However, these also amplified non-target species (e.g., Desulfobacterota). Finally, I designed a third set of primers (DS_F/DS_R) specific to Desulfurella sp., confirmed by in silico testing. These primers allow assessment of Desulfurella sp. and broader Campylobacterota before sequencing. The second experimental chapter focuses on enriching the target using the previously described primers, classical cultivation techniques, and molecular tools. Site selection was based on the 1000 Springs Project (Power et al., 2018). Culturing was performed originally with DSMZ Desulfurella medium and later modified, investigating pH (4 and 6) and temperature (50°C and 30°C) variations and adapting it for solid media by replacing elemental sulphur with sodium polysulfide. I used a vacuum food sealer to cultivate anaerobes, an accessible and portable alternative to expensive anaerobic chambers. Automated Ribosomal Intergenic Spacer Analysis (ARISA) was used to assess axenicity before sending samples for 16S rRNA gene and whole genome sequencing. Desulfurella was detected in each culture using species-specific primers (DS_F/DS_R), enabling its phylogenetic placement. However, despite Desulfurella presence in the 16S rRNA gene amplicon sequencing, a metagenome-assembled genome (MAG) could not be produced. This thesis discusses lessons learned and suggests improvements for future studies.
Evaluating biochar and fungi for the remediation of PFAS in landfill leachates.
(Thesis, The University of Waikato, 2024-10-20) Chauhan, Rushirajsinh
Per- and polyfluoroalkyl substances (PFAS) have become widespread environmental contaminants, often detected in various ecosystems, including waterways, and found in numerous products such as cosmetics. In New Zealand, PFAS contamination poses a significant risk to both environmental and human health. This study works towards developing an innovative PFAS removal technology utilizing biochar to adsorb PFAS and fungi to degrade PFAS. The work was broken into several stages, the first finding suitable growing conditions for fungi on biochar and attempting to quantify the growth, the second examining biochar adsorption properties, first with humic acid and the second with PFAS. Three different types of fungi, Oyster, Shiitake, and Pekepeke (native to New Zealand), were cultivated on biochar and substrates made from woodchips and other organic materials. Growth was best on a combination of biochar and woodchip. The chloroform fumigation method showed that the oyster/biochar culture had a growth of 17.6 mg/g/day, while shitake/biochar was 14.6 mg/g/day and the oyster/biochar/woodchip had a growth of 20.7 mg/g/day. Biochar had a low adsorption capacity (5 mg/g) and affinity for humic acid. The Freundlich isotherm gave a marginally better fit to adsorption data than the Langmuir and SIPS isotherms. The low adsorption was due to both humic acid and biochar having predominantly negative charges, biochar had a surface charge of 0.824 mM -ve charges/g biochar, six times that of dry soil which has a surface charge of 0.125 mM/g soil. Biochar was tested for its ability to adsorb three species of PFAS (PFBSA, PFHexA, PHHepA). Under the environmentally relevant PFAS concentration ranges tested, biochar adsorbed all of the PFAS, resulting in no PFAS being able to be detected in solution. PFAS adsorption to the biochar is predominantly by hydrogen bonding
Anhedonia: He kohinga whiti mai i te tirohanga o ngā wahanga e rima o te pōuri / A collection of poetry themed around loss presented through the lens of the five stages of grief
(Thesis, The University of Waikato, 2024) Nicholls, Rawiri Rangihouhiri Terrence
Anhedonia is a collection of personal experiences centred around loss examined through the lens of the five stages of grief (denial, anger, bargaining, depression, and acceptance) and framed within a personal confessional postmodernism style. It was also influenced by the collected works of Federico Garcia Lorca, Sylvia Plath, Cassandra Barnett (Ngāti Huri, Raukawa), Kirsty Dunn (Te Aupōuri, Te Rarawa), and Ngahuia Te Awekotuku (Te Arawa, Tūhoe). While loss and grief are intrinsically linked to death, within this collection, I further explore other forms of loss and grief. I touch on my loss of cultural identity, mind, and self. As a student, I have been diving deeper into my cultural identity of being Māori and what that means to me. I have lost many things throughout my life at the hands of abuse, depression, grief, and mental health. The poetry within this collection will continue to serve as a blunt reminder of the experiences (both positive and negative) that I have endured or witnessed over the last couple of decades. I have seen a multitude of losses (in its many variations) as I continue the dance to discover what the mortality of not only myself but those around me means to me. While everyone will experience feelings of grief and loss, I have framed my own experiences in my interpretation of our collective mortality.
Bridging manual labour and mechanisation: Enhancing blueberry harvesting efficiency for New Zealand’s fresh market
(Thesis, The University of Waikato, 2024) Sim, Sheau Lan (Alicia)
This thesis addresses the challenges of fresh market blueberry harvesting in New Zealand, where rising global demand and labour shortages put pressure on traditional handharvesting methods. Although hand-picking remains the industry norm, it is labourintensive and costly. With global blueberry consumption projected to grow, developing efficient and sustainable harvesting methods is critical, particularly for local growers. The core objective of this research was to develop a human-assisted mechanical harvesting system tailored for tunnel-grown fresh market blueberries. This system utilises lightweight, battery-powered handheld reciprocating shakers and multi-level soft surface catchers designed to reduce harvest damage, minimise ground loss, and improve fruit quality and yield. Performance assessments compared this system to traditional hand harvesting regarding post-harvest quality and harvest rate in field trials across two seasons. The field trials yielded valuable findings. In Field Trial 1.0, the Catcher V1.0 showed promising results, achieving a harvest efficiency of up to 83.7%, slightly less than the 89.3% efficiency of hand-harvesting into buckets. In Field Trial 2.0, the optimised Shaker V2.0 had a harvest rate of 81.3 berries/min, outperforming traditional hand-harvesting into a bucket (71.8 berries/min) and hand-harvesting into Catcher V3.0 (80.3 berries/min). Notably, Catcher V3.0 caused the least berry damage (0.9%), confirming the benefits of its soft surface design. For the Masena cultivar, optimal shaker settings were identified at 899 RPM and a shaking duration of 1.08 seconds, achieving a projected harvest performance score of 81.76%, with detachment accuracy of 93.21% and detachment efficiency of 96.53%. Future research should focus on larger-scale trials, long-term economic analysis, and developing methods to assess bloom retention. The integration of machine vision could further enhance this system, enabling fully automated harvesting, even during nighttime operations. These innovations have the potential to improve efficiency and sustainability for New Zealand’s blueberry industry.
Automation of the landing error scoring system using inertial measurement units
(Thesis, The University of Waikato, 2024-07-28) Hamilton, Zane
The quantification of biomechanics is important for making informed decisions when implementing appropriate training interventions for improving performance and reducing injury risk. This study evaluated the viability of movement data provided by wearable inertial measurement units (IMUs) to automate the scoring of the Landing Error Scoring System (LESS). The LESS is an assessment tool used for identifying high-risk movement patterns in a double leg jump landing; however, the LESS is scored by experts using 2D video recordings, which limits large-scale screening. Movement data provided by three IMUs were used to train several out-of-the-box machine learning models, aiming to predict the result of the 17 LESS scoring items individually. Raw movement data was processed and segmented into the key phases of the movement, where additional features were derived from these segments. A supervised learning approach was taken, using a dataset containing 218 LESS scores derived from 40 participants as the desired output for each model. Comparisons were made between various subsets of features, and the features with the greatest importance on accuracy in the best performing models were extracted. Results showed limited improvements to a ZeroR approach, and features with the greatest importance on the best performing models had minimal relevance to the movement involved. Performance of LESS scoring automation using IMU data may be improved with further developments on this approach.
Joy lands
(Thesis, The University of Waikato, 2024) Agrawal, Shivani
For as long as I can remember, I have been sad. When I moved from India to Aotearoa alone at eighteen, I hoped something would sand down the grief – the Pacific, green air, sidewalk lichen. I created my own displacement and I did not know how to initiate my return. This is what precedes joy. I had not yet learned that you have to look for joy. You have to recognise it when it arrives. Before I could see that it was joy that ate wonton soup with me and found me by the lake in fur slides – it ended. I was on a one-way plane to India and my body would never be these joys again. This is what follows the end of joy. When joy ends, it is impossible not to notice the ways in which the world demands suffering from us. We lean on no one, cry in bathrooms and eat alone. The world spins sadder. This is why you must pursue joy. JOY LANDS is a poetry collection about finding joy across lands and inside bodies through language, girlhood, queerness, and long-haul flights. While these poems are forever in motion across time and space, they are rooted in the presence of other people and in small, indelible moments of tenderness – an almost-wishbone neck, yolk-yellow tulips, taking turns to piss. The collection is split into three sections, each querying the conditions for joy: something unjoyful, if not terrible, must precede it; some form of hurt must always follow the end of it, and you must continue to pursue joy. JOY LANDS is a pursuit – I enter joy. I witness joy. I make joy. These poems are lonely and dream-like, funereal and moon-shaped, and bright hot orange. Joy is a build-up and I am just getting started.
Ka pūhia te puna o te kauae runga, kia pūheke ai ngā wai ki te kauae raro: Investigating the inclusion of Māori in engineering - A Māori engineers’ journey
(Thesis, The University of Waikato, 2024) Poli, Teresa
This thesis explored views held by Māori and non- Māori regarding te ao Māori across the engineering system of education, academia, and industry, in understanding what challenges and experiences Māori engineers may face. While there are incremental and progressive changes beginning to be seen in the engineering industry when working with iwi Māori, the history of engineering itself is intertwined with colonial contributions that have oppressed Māori. These historical influences continue to impact Māori today as they navigate educational pathways and enter the engineering profession. Colonisation, with its consequences such as stealing te reo, and various forms of cultural oppression, has led to Māori feeling disconnected from the engineering profession. It has also resulted in invisible cultural labour being placed on Māori, as we transition into a profession attempting to rectify the historic wrongs of the past. It was realised a gap existed in engineering education, failing to adequately equip graduates with the essential skills needed for success as engineers in Aotearoa. This gap was particularly evident in the cultural skills necessary for effective collaboration with clients, as well as for working harmoniously with Māori colleagues. The research framework employed in this rangahau was He waka hourua, symbolising the journey towards a vision where Māori not only hold mana but also a sense of belonging in the field of engineering. This framework recognises the importance of both Māori and Pākehā voices, with a preference for Māori engineers taking a leading role in steering the direction towards the envisioned destination. The data collection process involved the use of Surveys and Whakawhiti kōrero methodologies, gathering both quantitative and qualitative information that played a crucial role in shaping the research findings. Woven throughout this rangahau are the personal experiences shared by the author, and her journey as a wahine Māori engineer through the engineering system, anchored by her Māoritanga. Throughout, this rangahau analogies of waka are utilised as an acknowledgement of the great engineering feats developed by Māori, and paying homage to the idea that Māori have always been engineers, drawing from characteristics and traits passed down from atua and tīpuna. The author highlights the scarcity of literature dedicated to supporting the kaupapa of enhancing the mana of Māori in engineering. Rather than providing definitive answers to address the challenges that diminish Māori mana in engineering, this thesis serves as a foundational point, anchored at the wharf, for future rangatira to continue the voyage. Enhancing the mana of Māori in engineering presents an enduring wero, but there is optimism for the future of Māori in engineering, as we carve out institutionalism, we begin to make space on our waka.

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