Welcome to Research Commons

Recent Submissions

  • Item
    A toolbox for the use of electromagnetic induction technology and quasi-3D inversion to determine the spatial heterogeneity of soil texture and moisture in forested catchments
    (Thesis, The University of Waikato, 2023) Corbett-Lad, Priscilla
    Forest soils are critical to forest health and productivity, and by recognising their spatial heterogeneity, we can optimise productivity and preserve our natural resources in the face of a changing climate. Electromagnetic induction (EMI) technology provides a repeatable, non-destructive, and cost-effective approach to studying soil heterogeneity in managed forests. Electromagnetic induction technology has proven its versatility in agricultural settings to map soil texture, moisture and crop productivity and geological and archaeological exploration to identify underground natural and anthropogenic structures. Yet, the application in forests has been limited, and it is essential to understand the impact of soil and environmental factors on apparent electrical conductivity (ECa) if attempting to use this EMI technology in a forested environment. The overarching aim of this thesis was to determine if EMI can be used in a forested environment, focusing on two contrasting Pinus radiata D. Don production forests to capture the spatial heterogeneity of soil properties. Furthermore, this thesis can serve as a 'toolbox' for measurement protocols and analysis for forest owners interested in low-cost, time-efficient methods of understanding microsite heterogeneity in their forest soils to guide management practices. The research addressed the three main questions: The impact of various environmental factors on apparent electrical conductivity (ECa), the ability of ECa to characterise soil texture and moisture across forested catchments, and the effectiveness of quasi-3D inversion software in capturing the spatial heterogeneity of forest soils in three dimensions. To answer the first question, measurements were taken on forest litter thickness, gravimetric water content, density, soil temperature, ambient temperature, instrument temperature, and instrument voltage. The study found no significant linear relationship between ECa and these environmental factors, indicating that a correction factor for drift in ECa caused by temperature and voltage variations was not required. The insulating effect of forest soils, the forest canopy, and the instrument's housing played a role in maintaining stability. In addition, there was no significant effect of the presence or absence of forest litter on ECa, which was most likely due to the structure and makeup of forest litter, indicating that EMI technology could predict soil properties without considering the effect of forest litter. Questions two and three aimed to evaluate the effectiveness of using apparent electrical conductivity and modelled electrical conductivity (ECm) as predictors for soil properties, including gravimetric water content (GWC), the electrical conductivity of a 1-part soil to 5-part water solution (ECe1:5), and the percentages of clay (CLAY), fine sand (FSAND), and medium sand particles (MSAND). Firstly, generalised linear mixed-effects models (GLMERs) were employed to assess the measured variables' main effects and interaction effects on ECa and ECm and the within and between site variability as a random effect. The GLMERs demonstrated that incorporating multiple predictor variables reduced unexplained variability, with specific interactions, such as GWC and ECe1:5, playing crucial roles in explaining ECm variability at particular depths. However, multicollinearity issues were observed, primarily driven by the GWC-ECe1:5 interaction. The study also discussed the findings of 3D inversion maps of ECm, which provided detailed insights into spatial distribution patterns, particularly when overlaid with topographic and soil variable data. Secondly, one-dimension and three-dimensional maps were produced and overlaid onto base maps of each catchment to identify spatial patterns within each catchment related to soil texture and moisture using standard kriging in Arc GIS Pro software and custom EM4Soil software designed to interpolate one-dimensional ECa measurements into three dimensions. Finally, the research delved into the implications of these findings for forest owners and their management practices. It emphasised that while ECa technology is a valuable tool in predicting forest soil heterogeneity, it should not be used in isolation, and soil sampling and validation remain essential. The study recommended using EMI as a time and cost-effective tool for understanding soil heterogeneity, offering repeatable and non-destructive measurements for informed land use decisions. Overlaying spatial maps with additional geospatial data was recommended to comprehensively understand soil variability within catchments.
  • Item
    Non-market valuation of urban ecosystem services in Penang, Malaysia
    (Thesis, The University of Waikato, 2024) Koay, Chia Chia
    This thesis explores the non-market values of ecosystem services in Penang's urban green spaces, addressing threats posed by urbanization. Utilizing non-market valuation techniques, this study aims to provide a comprehensive understanding of the contributions of urban green spaces to the local economy. The first topic assesses urban residents' preferences using the best-worst scaling method, highlighting air quality as crucial but revealing inconsistencies in preferences. The second topic applies the travel cost method to analyse visit preferences and behaviours, emphasizing the significance of incorporating time-related costs for understanding travel patterns. The third topic employs a discrete choice experiment to reveal trade-offs between green space characteristics and travel distance, emphasizing the high value placed on improved air quality. The fourth topic uses a Seemingly Unrelated Regression model to explore the impact of spatial data on willingness to pay, showing insights into how spatial characteristics influence preferences. The fifth topic employs a simulation framework to assess the economic benefits of attribute changes in Penang's urban green spaces, emphasizing increased consumer surplus with improvements. Overall, these findings contribute valuable insights into resident preferences, spatial influences, and economic implications, offering guidance for sustainable urban development to local policymakers.
  • Item
    Investigating teachers’ lived experiences in teaching Literature in English in Ghana
    (Thesis, The University of Waikato, 2024) Adjei Baah, Eric
    This thesis investigates the professional experiences of a group of Literature in English secondary school teachers in Ghanaian schools. At the secondary level, LiE is an elective (optional) subject, and so we could expect that those choosing it would probably do well. However, this thesis investigation arose from a concern about the persistent lack of quality of student achievement in this subject, as noted in the annual Chief Examiner’ Literature in English report. These reports outlined challenges students face in responding to West African Secondary School Certificate Examination (WASSCE) Literature in English questions. I was curious about understanding what might be behind this persistent issue. Though English is the official language and medium of instruction from the upper primary to the tertiary level in Ghana, English is a second language. This is important when considering the nature of texts mandated by the West Africa Examination Council (WAEC) Ghana every five years. In order to investigate this Literature in English phenomenon, I recruited volunteer teachers from Ashanti Mampong Municipal, using phenomenology as the methodological framework. As part of the investigation, I reviewed teachers’ perspectives about their professional lives through the lens of PCK, since teachers’ knowledge is an important element in teaching specific subjects. I also sought to know more about their professional teaching conditions - both barriers and enablers. The findings revealed teachers’ great passion for the subject and what they thought it could provide for students’ learning in terms of reading, critical thinking and writing skills. However, major barriers interfered with their good intentions: - the unreliability of having mandated texts available in a timely manner - the cost of texts to students and teachers, who must purchase them - the language complexity and cultural, social and historical contexts of some set texts - class sizes. The findings implied that if texts were supplied in a timely manner, and offered for students and teachers to borrow rather than purchase outright, then teachers would not need to find their own workarounds to manage the lack of texts. Also if the West Africa Examination Council (WAEC) chose more contemporary and local texts, students might be more familiar with the language and contexts of the literature, and thus be more able to offer original perspectives. Teachers also had to manage large classes, making it difficult to meet students’ specific learning needs. Such barriers are likely to mitigate against teachers using the kinds of co-constructive, student-centred pedagogical practices known to enhance learning and leverage teachers’ PCK. Instead, they resorted to a range of teacher-centred pedagogies, especially when neither students nor teachers could access copies of the set texts. Revealing these barriers to learning can inform WAEC as it makes the next set of mandated literature choices for the next five year term. Should the government also review the status of the subject and how learning materials are provided in a timely manner, this might also benefit both learners and teachers. For participant teachers themselves, knowing their experiences - both positive and negative - are shared, may help them develop networks of professional support to mitigate the effects of access, class size, and text difficulty. In the end, these relatively small changes may be significant in positively altering the experiences of students and teachers in classes of Literature in English.
  • Item
    Out-of-distribution detection with deep hybrid models
    (Thesis, The University of Waikato, 2024-03-17) Schlumbom, Paul-Ruben
    Deep learning systems suffer from “silent failures” where they make highly confident, but incorrect, predictions for input instances well outside of their training data. This motivates the development of out-of-distribution (OOD) detection for such systems: the ability to recognise when an input deviates significantly from the training data. The “deep hybrid model” (DHM) for image classification presented by Cao and Z. Zhang (2022a) uses a normalising flow to perform density estimation for OOD detection and addresses shortcomings of approaches that model pixel-space densities: it performs density estimation using classifier features. Remarkably, Cao and Z. Zhang (2022a) claim 100% detection accuracy on a number of common benchmarks but do not make their code available. As we find the principles behind the DHM interesting and sound, we reimplement it to either confirm its capabilities or understand why it falls short. We perform an extensive search over possible model configurations to maximise performance and provide a detailed record for best practice. Although unable to achieve 100% detection accuracy in our experiments, the DHM delivers competitive performance with careful fine-tuning, while exhibiting great sensitivity to hyperparameter settings. We argue that this is predominantly due to an adversarial relationship between the classifier and the normalising flow that can result in the collapse of the feature space. We verify this by means of several synthetic datasets and show that one of the assumptions underlying the DHM architecture, that the feature extractor can be regularised to preserve input-space densities in feature space, is not satisfied, thereby providing an understanding of where the DHM falls short and informing the development of future OOD detectors based on modelling feature space densities. We also evaluate the DHM on a real-world dataset of endemic and invasive stink bugs in New Zealand that poses a fine-grained OOD problem due to the high visual similarity between the bug species. Low DHM performance, compared to OOD benchmarks, reveals the benefit of testing OOD systems in real-world settings.
  • Item
    Making sense of diversity’s complexity: Leadership’s agency for diversity management
    (Thesis, The University of Waikato, 2024) Chua, Shireen Wei Yuin
    This research examines leadership’s role in their organisation’s diversity management efforts. The management of a diverse workforce in today's organisations is becoming increasingly complex. It needs to go beyond considering not only the surface-level dimensions of diversity, but also the hidden and dynamic deep-level diversity dimensions in organisations, that are considered complex systems. Surface-level diversity dimensions include gender, age, race, ethnicity, and accessibility. Deep-level diversity dimensions are the hidden values, worldviews, personality, and experiences of individuals in organisations. In today's socio-cultural context, the heightened awareness and interest in matters relating to equity, diversity, and inclusion (EDI) is driving organisations to seek ways to address how to manage their diverse workforce that will unlock the benefits that diversity has promised. Diversity management approaches that only consider surface-level dimensions are no longer adequate. To unlock further the benefits of diversity consistently in organisations today, diversity management approaches must include deep-level diversity characteristics. This shifts diversity management approaches that have managed the various surface-level diversity characteristics to approaches of managing for diversity that require an organization-wide approach. Diversity management today requires the senior leadership team to play a strategic role. As organisations adopt a more holistic and systemic approach to their diversity management efforts, it requires the leadership to strategically manage their organization’s diversity management efforts. This goes beyond the diversity initiatives such as creating policies, initiatives, events and programs that celebrate diversity to behaviours that foster a diverse and inclusive workplace. However, the strategic diversity leadership in their organisation's diversity management efforts has not been fully explored. This thesis seeks to explore two research questions. Firstly, it seeks to identify the factors that influence the three leadership dimensions of diversity management and the factors influencing the leadership’s strategic role in their organisation’s diversity management efforts. Secondly, it seeks to map the three leadership dimensions into an emergent model of leadership agency for diversity management. Drawing from the literature review, three dimensions addresses leadership’s strategic inclusive leadership. Leadership accountability, leadership approach and leadership focus for diversity management describe different facets of the leadership’s strategic role. Central to addressing leadership’s strategic role is to further the understanding the factors that influence leadership in their organisation’s diversity management efforts. Leadership agency describes the capacity and authority of senior leadership team to influence, to make strategic decisions and take action to meet their organisation’s outcomes and goals. In the case of diversity management, leadership agency describes identifying and understanding the factors that influence leadership in their strategic inclusive leadership. The research questions of this study identified the factors influencing leadership agency in three dimensions of diversity across the different levels of the organisation. It also proposes an emergent model that maps an organisation's leadership agency for diversity management that provides a visual and practical model of leadership’s agency for diversity management. The study uses complexity theory as its theoretical base within an interpretive philosophical base and constructivist paradigm to examine leadership agency for diversity management. This research provides insights into leadership agency for diversity management in today's organisations through a multiple case study method. Using qualitative methodology, ten organisations participated in this research to determine leadership agency for diversity management. This study makes original contributions by addressing the leadership’s strategic role in diversity management through the lens of complexity. It also contributes to the research into organisational diversity management theories by developing a practical emergent model that highlights the crucial role of leadership agency in achieving positive diversity management outcomes, especially addressing the complexity of diversity. The study uses a multilevel lens to explore how leadership approaches managing their diverse workforce. It proposes an emergent model of leadership agency for diversity management as a tool that can help organisations gauge their level of agency. This study underscores the importance of intercultural sensitivity development in future research on leadership’s agency for diversity management. Further theoretical development is necessary to enhance these findings' validity and reliability and identify leadership agency practices that support effective diversity management in organisations.

Communities in Research Commons

Select a community to browse its collections.

Now showing 1 - 2 of 2