ResearchSpace@Auckland
University of Auckland Research Repository - ResearchSpace
ResearchSpace is an online archive for the University of Auckland and contains full text theses and other research outputs.
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Building Information Modelling-based Smart Inspection Data Management for Unmanned Aerial Vehicle-enabled Visual Building Inspection
(ResearchSpace@Auckland, 2024) Zhang, Cheng; Zou, Yang; Dimyadi, Johannes; Chang-Richards, Alice
Unmanned Aerial Vehicles (UAV) equipped with red, green, blue (RGB) and thermal cameras have been growingly used for visual building inspections. However, its full potential remains untapped due to challenges in managing fragmented and distorted images. While Building Information Modelling (BIM) has been envisaged as an effective platform for managing building lifecycle data, its potential for handling UAV inspection data has not been explored. To address this challenge, this doctoral research has investigated the use of BIM to establish a smarter and more efficient method for managing the UAV building inspection data.
Firstly, a systematic review was conducted on the state-of-the-art UAV and BIM applications in visual building inspection. The review findings revealed four key research gaps.
Secondly, the research conducted a comprehensive investigation in effective UAV thermal image acquisition strategy, focusing on three critical factors: temperature difference between building interior and exterior, ground sampling distance (GSD) of thermal images, and UAV oblique angle. The impact of these factors on inspecting façade anomalies was examined both qualitatively and quantitatively through laboratory and field experiments.
Thirdly, the research proposed a BIM-based scheme for managing fragmented and distorted UAV images. An improved Generalised Hough Transform (GHT) method was developed for aligning RGB images with BIM by matching building façade features. However, this method faces certain obstacles when dealing with specific types of façades, such as curtain walls. To overcome this, a Structure from Motion (SfM) method was introduced as a supplementary solution. Additionally, perspective and geometry distortions on UAV images, especially when inspecting single-curved façades, were eliminated by BIM-based 3D surface unwrapping.
Moreover, UAV thermal images were calibrated, corrected, enhanced, and registered onto BIM through multi-source image fusion and histogram-based correction. The effectiveness of the proposed scheme has been validated by computer simulations and field experiments, demonstrating its ability to convert fragmented and distorted UAV RGB and thermal images into a distortion-free panoramic image, seamlessly integrable into BIM.
Finally, an implementation of a system that consolidates all developed approaches has validated the formulation of an effective UAV image acquisition strategy with efficient inspection data management in BIM.
Contemporary Central Banking - Analytical Perspectives
(ResearchSpace@Auckland, 2024) Haworth, Cameron McFarlane; Gai, Prasanna
This thesis considers the design of contemporary central bank policy from a theoretical perspective.
In Chapter 1, we investigate the effects of central bank commitments to alternative monetary
policy tools. We present a simple model to characterise central bank forward guidance, large scale
asset purchases and yield curve control. Endogenous yield curve reactions to policy shocks are a
key determinant of monetary conditions and can support or offset policy intentions. Alternative
monetary policy tools allow the central bank to signal central bank private information to investors
when the policy rate is at the effective lower bound, shaping yield curve reactions. Commitments to
these tools offer policy certainty but can become time-inconsistent if the economy recovers sooner
than expected. If commitments become time-inconsistent, endogenous yield curve tightening can
offset excess stimulus. The strength of this offset, and the optimality of monetary conditions,
improves with the precision of investor inferences of central bank private information.
In Chapter 2, we examine the causal link between asset bubbles and wealth inequality in a twoagent
macroeconomic model. Bubbles influence wealth inequality through two channels: altering
the debt-asset ratio and fuelling speculation. When bubbles grow, they can temporarily decrease
wealth inequality if asset prices rise faster than debt. However, when they burst, wealth inequality
increases as the debt-asset ratio rises. Steady state wealth inequality is unaffected by bubbles if
household types share symmetric speculative timing. Although macroprudential policy, communication,
and leaning against the wind can reduce negative bubble effects on aggregate utility, they
have a limited effect on wealth inequality.
In Chapter 3, we introduce cautious expectations to a macroprudential policy model where average
growth is traded off against growth-at-risk (GaR). Policymakers with cautious expectations estimate the optimal weight to apply to risk signals, creating biased, historically dependent crisis
forecasts. They optimally downweight the effects of risk and their policy settings on GaR forecasts,
decreasing the expected efficiency of the growth-GaR trade-off. This loosens the optimal policy
stance, but also causes policymakers to respond more aggressively to changing signals. As policymakers
experience additional crises, they better understand the effects of their policy instruments
and tighten their stance. When past crises are forgotten, this tendency reverses.
The Expectancy Effect and Psychedelic Microdosing: An investigation of whether expectation manipulations can enhance analgesic and cognitive performance
(ResearchSpace@Auckland, 2023) Letica, Mirabella Mary; Reynold, Lisa
The utilisation of psychedelics in healthcare is gaining popularity as a therapeutic tool for various physical and psychological disorders. Albeit less studied, psychedelic microdosing is gaining more attention from researchers. Current anecdotal reports and observational studies proclaim various benefits from psychedelic microdosing. However, scientifically rigorous randomised controlled trials are limited. It is, therefore, unclear whether the reported benefits result from psychedelic microdosing or psychosocial factors, namely placebo effects.
The present study investigated whether manipulated expectations of the analgesic or cognitive benefits of microdosing can influence individuals' objective performances and subjective perceptions of performance on a series of cognitive and analgesic tasks. Participants were randomised into three expectation groups; The analgesia manipulation group were informed that microdosing has analgesic effects, The cognition manipulation group were informed that psychedelic microdosing has cognitive benefits, and the control group did not receive any expectations. All participants consumed a placebo pill containing 100mg of Niacin, which they were told was a psychedelic microdose. Objective performance scores and subjective ratings of felt pain and cognitive function were recorded at baseline and post-microdose consumption. Participants' perceptions of felt pain relief and cognition enhancement were also collected post microdose consumption.
Eighty-eight participants completed the experimental session; seven were excluded from the initial analysis. 84% of participants believed they consumed a psychedelic microdose. The 13 participants (16%) who believed they consumed a psychedelic microdose were also excluded from the analysis. The results indicated that the analgesia manipulation group held higher pain reduction expectations than the other two groups. In comparison, participants in the cognition manipulation group held higher expectations of memory enhancement but not concentration or problem solving. Regarding pain outcomes, the analgesia manipulation group reported greater analgesia compared to the cognition manipulation group. Regarding cognition, neither objective performance nor reports of cognitive enhancements were shown in the cognitive manipulation group.
The present study is the first to investigate the relationship between placebo effects and psychedelic microdosing. Further, it demonstrates a novel experimental design that can effectively investigate microdosing. The findings suggest that people's expectations can influence the reporting of microdosing benefits– particularly regarding analgesic effects. The extent to which expectation contributes to broader reports about microdosing effects is still unknown and thus requires further investigation. Future research should continue to explore whether expectancies contribute to other reported microdosing effects and whether specific populations are more at risk of placebo responding.
Synthesis of Antiviral Imino-C-Nucleoside Analogues
(ResearchSpace@Auckland, 2023-10) Wong, Chi Hung Andy; Brimble, Margaret
Nucleoside analogues are a diverse class of synthetic drugs that exhibit broad antiviral and anti infective activity. Critically, nucleoside analogues serve as first-line therapeutic agents to treat viral infections of pandemic potential. Despite various clinical successes, nucleoside drug discovery has been hampered by inefficient access to unnatural nucleoside frameworks, such as the iminoribitol scaffold observed in the adenosine analogue, galidesivir (29). With the overall goal of streamlining the synthesis of nucleosides, the modular assembly of imino-C-nucleosides was devised, featuring use of a cycloaddition reaction as the key heterocycle-forming step.
The first part of this work involved identification of an appropriate alkyne-bearing intermediate that would be compatible with the proposed cycloaddition reaction and downstream transformations to effect nucleoside synthesis. To this end, divergent access to both imino-C-nucleoside anomers was established from protected D-serine 112. Hemiaminal 130, when subjected to a telescoped cycloaddition and pyrrolidine formation sequence, showed preference for α-nucleoside formation. On the other hand, the analogous cycloaddition and deprotection using alkynyl pyrrolidine 148 led to the exclusive formation of the desired β-nucleoside 139·HCl.
The second part of this work elaborated on the cycloaddition strategy as a rapid method to introduce diversity in medicinal chemistry campaigns. To maximise the efficiency of triazole construction, a one-pot method was developed for the in-situ generation of aryl or heteroaromatic azides from the corresponding boronic acids using Chan-Lam-type conditions, that were then captured for concomitant Copper-catalysed Azide Alkyne Cycloaddition (CuAAC). Copper-cyclodextrin complex was identified as the superior catalyst for this transformation. After extensive optimisation, 24 analogues were prepared from advanced alkyne 200 using the developed protocol. Synthetic efforts were supported by structural analysis and antiviral assessment of the flex-imino-C-nucleosides, a subclass of nucleoside analogues characterised by a split arene ring motif.
This work provides insight for the continued development of nucleoside analogues, whereby use of a cycloaddition strategy could be broadly implemented for the convenient access to C-nucleosides bearing unique heterocyclic nucleobase surrogates in future diversity oriented syntheses.
Corporate Disclosure Strategies among Chinese Firms: Insights from CSR Reporting, Value-reducing M&As, and the COVID-19 Pandemic
(ResearchSpace@Auckland, 2024) Yin, Fangyi; Cahan, Steven; Chen, Jerry
The overarching theme of this thesis centres on corporate disclosure strategies of Chinese A-share firms in varying contexts. It comprises three studies, each delving into how firms adapt their disclosure practices in response to peer influences, the challenges of investor relations management, and the demands of crisis communication, respectively.
The first study (Chapter 2) investigates industry peer effects under China’s selective mandatory corporate social responsibility (CSR) disclosure regime. It reveals that non-mandated firms are more likely to voluntarily disclose CSR information when a higher proportion of industry peers are mandated to do so, exhibiting a positive peer effect. On the other hand, firms that already engage in voluntary CSR disclosures tend to cease these practices as the number of mandated disclosers in their industry increases, indicating a negative peer effect where firms free-ride on peers’ mandatory disclosures.
The second study (Chapter 3) examines how firms strategically manage their disclosure tone after value-reducing mergers and acquisitions (M&As). The findings suggest that acquirers tend to employ a negative tone in their CSR reports aimed at institutional investors, while adopting a positive tone on the Interactive Investor Platform (IIP) that is mainly used by retail investors. This inconsistency in disclosure tone between the platforms appears driven by an intent to inform institutional investors and, at the same time, mislead retail investors, consistent with the acquirer “speaking in two tongues” after negative events.
The third study (Chapter 4) focuses on firms’ communication strategies during the novel Coronavirus disease (COVID-19) pandemic. A difference-in-difference (DID) analysis reveals that firms subject to complete or partial lockdown shift to a more positive reply tone on the IIP in response to a less positive ask tone from retail investors. This overly optimistic tone, linked to poorer future firm performance, suggests firms’ attempt to mislead retail investors during the lockdown; however, the market reaction tests show that the impact of such opportunistic behaviour is short-lived.