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Monitoring fire-driven forest dynamics over large areas using passive and active remote sensing
No full textForests are an integral part of the Earth’s biosphere, hosting a large proportion of global biodiversity and serving as a major stabilising factor in climate and weather regulation. To ensure their protection, nature reserves and national parks have been established in many parts of the world. Nevertheless, forests are increasingly under stress from the consequences of climate change and other human-driven pressures. In Australia, as in other regions of the world, wildfires are becoming more frequent and severe. Despite the evolutionary adaptation of Australian native vegetation to wildfires, concerns have been raised regarding the resilience of local forests to the changing fire regimes, and their ability to sustainably recover from fire.
Satellite-based remote sensing has been shown to be a reliable and practicable solution for mapping and monitoring forests over large areas. Passive sensors such as those on the Landsat satellites collect multispectral information with a moderate spatial and temporal resolution, providing global wall-to-wall coverage that reaches back several decades. However, Landsat has
well-documented limits in monitoring vertical forest structure. As an active remote sensing technology, lidar can help to fill this gap. Its signal can penetrate the canopy layer and gather information on the vertical distribution of plant material. Combining the advantages of both sensor types has been shown to enable more accurate mapping of forest structure across large areas. In particular, the advent of spaceborne lidar sensors such as the Global Ecosystem Dynamics Investigation (GEDI) has boosted the use of sensor fusion approaches that leverage passive and active remote sensing data for forest structure monitoring. This thesis evaluates the utility of Landsat time series (LTS) and GEDI for mapping forest spectral and structural characteristics following fire disturbance events.
The first research question examined whether conservation efforts can be associated with forest resilience to fire. Specifically, it explored if forest tenure and protection status are related to post-fire recovery of forests. LTS satellite data was used to evaluate spectral recovery duration following fire disturbance for 25.4 Mha of forested land in southeast Australia. Results show that protected forests on public tenure spectrally recovered on average 0.4 years faster than those on privately held land. However, other factors such as climatic and topographic variables were found to have a far greater impact on forest recovery.
As spectral recovery does not necessarily equate to structural recovery, subsequent research questions focus on how GEDI data can be used in conjunction with LTS. While GEDI is superior to Landsat in measuring attributes of forest structure, it is constrained by a relatively short scheduled mission duration (2019 to 2023) and its design as a monotemporal sampling tool. This thesis proposes a novel approach to overcome these constraints, based on the use of bi-temporal GEDI data. The method leverages footprint-level lidar observations of forest structure from two points in time, using airborne lidar datasets from the pre-GEDI era to simulate a first set of GEDI observations, complemented by a second set of observations provided by the spaceborne GEDI instrument for the same footprint locations, respectively. Throughout this thesis, this concept is referred to as ‘bi-temporal GEDI’ data.
To validate this approach, the second research question compared real and simulated GEDI observations in undisturbed Australian sclerophyll forests. The results confirm that real and simulated GEDI observations, despite certain differences, are generally compatible for combined use in bi-temporal monitoring approaches. Additionally, recommendations were made for the settings of the GEDI simulator and specifications of ALS data used in the simulation. Furthermore, the research determined the main sources of error, namely steep slopes, dense canopy cover and dead standing trees. Highly irregular horizontal forest structure was found to pose a challenge, an issue related to GEDI’s geolocation uncertainty.
To facilitate the novel integration of bi-temporal GEDI observations into established LTS-based forest monitoring approaches, the third research question explored relationships between the two data sources, focussing on the post-fire vegetation response across a range of structural and spectral metrics. One year after the examined fire event, spectral indices showed a moderate to strong decline to between 46.1 and 77 % of pre-fire levels, while most structural metrics demonstrated an even more substantial decline. An exception was canopy height which only dropped to 82.7 % of pre-fire levels. Increased fire severity led to a more pronounced post-fire decline across several spectral and structural metrics. Similarly, greater forest height was found to be associated with a larger post-fire decline across some spectral and structural metrics. Furthermore, the findings suggest the preferential use of GEDI full power beam observations to increase the utility of derived structural metrics.
Finally, in the fourth research question, the novel concept of integrating bi-temporal GEDI into LTS-driven forest change monitoring was implemented. This study evaluated whether employing bi-temporal GEDI data resulted in improved model performance compared to using monotemporal GEDI. The findings show that leveraging bi-temporal GEDI data reduces the RMSE of canopy height change predictions by 0.94 m in undisturbed forest, and 0.49 m in recently disturbed forest. Similar trends were observed for other structural change metrics. Furthermore, the results demonstrate that in forest types with less dense canopy cover (<80 percent), canopy height change predictions from bi-temporal GEDI-driven models yielded a 1.51 m reduction in RMSE. Overall, the results provide evidence that Landsat-based models that were trained with bi-temporal GEDI data were superior in modelling vertical forest structure change, compared to more traditional approaches that were restricted to the use of monotemporal GEDI.
The approach of fusing bi-temporal GEDI observations with multispectral LTS data as presented in this thesis generated promising results, outperforming other more established methods. It can
be applied to enhance the monitoring of forest structure in temperate, subtropical, and tropical forests (i.e., areas covered by GEDI’s orbit between 52° N and S) where patches of historical ALS data are available. Leveraging bi-temporal GEDI data might be beneficial for biodiversity mapping, fire behaviour modelling or carbon budget monitoring, as well as studying the impacts of anthropogenic factors on forests
Moving still: exploring post-digital resonance in landscape and atmosphere across print interfaces
No full textIn artworks that depict landscape and atmospheric conditions, Moving Still explores the mediating effects of digital image filters such as bitmap or half tone dots. Deploying concepts of abstraction, depth perception, spatial interference, and time perspective, the research considers advancements and consequences of digital image technologies on representations of landscape. Employing a methodology that contrasts traditional and slow print technologies with contemporary and rapid print technologies, the research also visualises potential influences of contemporary mobility and duration on a perception of landscape. Studio methods developed during this research further investigate technological mediations on landscape images, through a painting method that is informed by a mechanical print-based process which mimics a photographic presence. The artworks challenge the observer to decipher filtered landscapes to provoke a consideration of the resonances of digital imaging on perceptions of landscape and atmosphere.</p
Strategies exhibited by bumblebees when challenged with aerodynamic and obstacle disturbances
No full textThe articulation evident in the wings of flying insects seems to enable remarkable steadiness when flying in unsteady atmospheric conditions and through clutter. Recently, there has been a substantial growth in micro air vehicles (MAVs), made possible by breakthroughs in battery technology and advances in manufacturing. However, the steadiness of such vehicles is far inferior to insects and there appears to be no commercially viable flapping-wing MAVs. The gaps in our understanding encompass several aspects of flight mechanics and environment, including flapping-wing aerodynamics and control, which, if filled, would enable steady flight through unsteady environments. In this thesis, bumblebees were experimentally investigated to draw a general understanding of the responses that occur when flying through typical disturbances that are ubiquitous in the normal outdoor environment: gusts and obstacles. In the first set of experiments, bumblebees were trained to fly through imposed, documented, repeatable gusts oriented in different directions and their flight responses were characterised. Gusts caused bees to exhibit unique wing stroke changes while responding to each gust case (sideward, upward and downward), with downward gusts causing the greatest flight deviations. The wing changes resulted in linked body orientation manoeuvres that typified the general trajectory changes through the gusts. Further experiments and analyses using a mechanised rotating flapper also indicated that downward gusts cause more adverse aerodynamic effects than the upward gusts. In addition, analytical models based on the actual wing strokes of bees recovering from gust perturbations gave insights into the kinematic strategies observed in bees when counteracting gust effects. In subsequent experiments, bees were made to encounter a sudden-appearing obstacle that forced them to engage in “all-out” braking. Bees showed consistent body re-orientations when dealing with the spontaneous braking demand. The magnitudes of active manoeuvres were found to be linked with the initial inertial properties of bees (mass, velocity, heading). The roll, pitch and yaw manoeuvres were significantly larger for bees with a greater braking challenge ahead of them (heavier and faster on approach). The handling via roll-based manipulation of the body—as opposed to exclusive use of pitch, as initially hypothesised—suggests that bees employ body rotations about the axes of lower moment of inertia, optimising for speed to rapidly engage in required force production. In addition, bees generally chose to undergo manoeuvres in the direction of initial heading offset. Both proclivities suggest awareness of the initial state and force modulation via body orientation changes. The behaviours of bees in both disturbance types revealed that body motion is an indicator for the underlying strategies of disturbance mitigation, as well as perception of flight state and modulation of response dynamics according to the control demand. The coordinated actions of bees were reasoned to provide control advantages for the perturbations studied, serving as inspiration for improved small-scale biological and engineered flapping systems
Transitory encounters: embodied artistic research to understand the lived experiences of Filipino domestic workers in Hong Kong
No full textTransitory Encounters examines embodied lived experiences through immersive performance practice. The research explores the role of embodiment in the formation of temporal social spaces used by Filipino domestic workers (FDW) in Hong Kong’s downtown Central district on their day-off. Each Sunday the workers claim public spaces by constructing structures and partitions using various materials --- sectioned and demarcated to create space for cultural connection, social relations, and to emulate a sense of home away from home. This practice- led research asks: How can my performance practice create encounters in social public space to engage with and more fully understand the lived experiences of Filipino domestic workers in Hong Kong?
In this artistic research, I adapted an ethnographic fieldwork method focusing on the sensuous and intuitive artistic forms of inquiry from the standpoint of the body as a research agent and as a vessel where embodied knowledge is stored. While there have been many anthropological and sociological studies on the phenomenon of temporary gatherings of FDWs in Hong Kong, the approach used in this research is distinctively arts-based. Through this fieldwork practice, I developed new immersive multidisciplinary performance research methods to invite participation and dialogue to further understand the lived experiences and phases of liminality experienced by the transitory migrant workers. Thus, the research concludes with discussion of the emergent performance models and fresh insights into performance-based research. Further these findings highlight the significance of performative embodied sharing of experiences in the creation of communicative spaces and social relations in public space
Time-images and digital fashion sculpture: investigating the in-between image in fashion
No full textThe fashion image is inextricably linked to the concept of time. It occupies a unique position between the past and the future, often engaging with unconventional models of time. The temporal nature of fashion imagery becomes even more pronounced with the introduction of new technologies such as photogrammetry and 3D scanning, for these have given rise to a form of digital fashion sculpture that transcends traditional modes of fashion photography and fashion film.
With these new technologies the fashion body moves away from conventional two-dimensional representation and becomes unflattened, unconfined and multi-dimensional. It can repeat, multiply, morph and stretch — a body woven and sculptured from pixels. This practice-based research project investigates the concept of the in-between image within the context of digital fashion film. It explores how the fashion image transitions from a two-dimensional plane into a three-dimensional experience by examining and playing with the temporal nature of the image. It asks the question: How can developments in 3D imaging technology contribute to the field of fashion imagery?
Motivated by the recent technological changes in fashion media, this research is contextualised by key theories of fashion, expanded photography, the body, and affordance. Using photogrammetry, I propose that digital fashion sculpture unveils new perspectives, exposing the fashion image’s construction, revealing flaws, crevices, and hidden details in both the body and garments, imperceptible to the naked eye or traditional cameras
Persist: an affective, autoethnographic feminist creative practice model
No full textIn this research project I start with a personal problem: How do I value my feminist creative practice? Why am I more attuned to perceptions of failure than success?
I draw on Sara Ahmed’s proposition that feminism is ‘an affective inheritance’ and ‘part of a wider struggle … to make sense of being’ (Ahmed 2017: 20). That is, if I have struggled to ‘make sense’ of failure and success as a creative writer, other practitioners probably have as well. These are loaded terms. They can have significant impact on a practitioner’s capacity to sustain practice. I want to interrogate them, via creative practice research, and see if I can ‘trouble’ the terms or reimagine them.
I develop a creative practice research methodology that is affective, feminist, autoethnographic and driven by poetic inquiry. Sandra Faulkner (2019: 14) defines this as ‘the use of poetry as/ in/ for inquiry’. I write and use poetry as a research tool and extend this inquiry to employ a poetic research approach, one that is associative, notices language, and seeks openness in form. The problem at the centre of my research dictates my methodology (Leavy 2017) as I bring it into relationship with my existing creative writing practice.
The project is supported by primary research of my community of practice through interviews, a critical and creative engagement with this community’s work, and reflection on my role within the community. By paying attention to the many ways in which practitioners work, and the many layers of practice in community, via reading, conversation, play and research, I reveal, via creative practice, a softening of adherence to form and to constructs (of success and failure and value). In this way, the project generates insights into how creative practice functions as research and proposes new ways to see the value of feminist creative practice
Determinants of Return and Volatility of Cryptocurrencies
No full textThe rise of cryptocurrencies has significantly altered the financial landscape, drawing considerable attention from both investors and researchers. This interest highlights the transformative potential of cryptocurrencies and underscores the need to understand the determinants of their returns and return volatilities. As a novel and distinct asset class, cryptocurrencies differ markedly from traditional financial assets, rendering traditional asset pricing models inadequate for their valuation. This thesis aims to bridge the gap between traditional asset pricing theories and the evolving cryptocurrency market.
Recent studies have attempted to apply common risk factors from traditional asset pricing models to the cryptocurrency market. However, these models often fail to fully account for the unique characteristics of cryptocurrencies, such as their decentralized nature and reliance on cryptographic technology. To address this gap, this thesis examines the effects of common risk factors (market risk premium, size effect, momentum effect), economic risk factors (money supply, investor attention), and technological risk factors (mining cost, scarcity effect) on the cryptocurrency market. By incorporating these diverse risk factors, this thesis provides a deeper understanding of cryptocurrency returns and return volatilities, ensuring the models reflect the distinct features of the cryptocurrency landscape.
The scarcity effect, categorized as a technological risk factor, emerges as a novel and compelling factor deserving investigation due to its fundamental role in shaping asset values and market dynamics. Unlike traditional asset classes, cryptocurrencies often have limited supplies or predetermined issuance schedules, leading to inherent scarcity. Understanding the interplay between scarcity and cryptocurrency returns offers valuable insights into cryptocurrency pricing and portfolio management strategies. Moreover, the scarcity principle, a fundamental concept in economics, presents an intriguing yet underexplored avenue in the context of cryptocurrencies. Through empirical analysis and methodological innovation, this thesis reveals a positive relationship between scarcity and cryptocurrency returns, extending the boundaries of the existing scarcity principle and enhancing our understanding of the cryptocurrency market.
This thesis undertakes a distinct examination of the determinants of Proof-of-Work (PoW) and Proof-of-Stake (PoS) cryptocurrencies, attributed to the contrasting consensus mechanisms inherent to each. By analyzing these cryptocurrencies separately, a deeper comprehension of the factors influencing their excess returns and return volatilities is achieved. Consequently, the construction of mimicking portfolios to explore the size effect, momentum effect, and scarcity effect of PoW and PoS cryptocurrencies is executed independently. This methodological differentiation acknowledges the distinctive attributes and consensus mechanisms of PoW and PoS cryptocurrencies, facilitating a tailored evaluation of their scarcity effects. Furthermore, mimicking portfolios for size, momentum, and scarcity effects are found to outperform their background factors, underscoring the importance of employing such portfolios.
To conduct a thorough analysis of cryptocurrency excess return determinants, this thesis employs Newey–West standard error regressions and two-stage least squares models, effectively addressing issues such as serial correlation, heteroscedasticity, and endogeneity. Robustness tests are conducted through three distinct methods. Initially, the impact of various factors including UCRYPOLICY, gold price, S&P 500 index, crude oil price, and hacking events is evaluated to gauge their influence on the results. Subsequently, the Autoregressive Distributed Lag – Error Correction Model (ARDL-ECM) is employed to validate the findings, ensuring the reliability of the results. Lastly, a panel data analysis is undertaken to collectively assess the significance of identified variables across all PoW and PoS cryptocurrencies. Further strengthening the conclusions, an evaluation is conducted on the impact of excluding Bitcoin and Ethereum from the analysis, revealing consistent results that underscore the persistent significance of the identified variables, thus confirming the robustness of the findings. The findings reveal common determinants for both PoW and PoS cryptocurrency excess returns. For PoW cryptocurrency excess returns, the main determinants are momentum effect, size effect, market risk premium, scarcity effect, investor attention, and mining cost. Meanwhile, for PoS excess returns, the main determinants are size effect, market risk premium, scarcity effect, momentum effect, and investor attention. Mining cost is exclusively applicable to PoW cryptocurrencies, as PoS cryptocurrencies do not rely on computational power for minting.
This thesis further investigates the determinants of cryptocurrency return volatility using the Generalized Autoregressive Conditional Heteroscedasticity (1,1) process. To validate the robustness of the findings, additional tests including Threshold-ARCH, Exponential GARCH (EGARCH), and Power-ARCH (PARCH) models are performed. Subsequently, Akaike's Information Criteria (AIC) and Bayesian Information Criteria (BIC) are utilized to identify the most suitable model for analysis. A GARCH (1,1) model is also applied to the panel data of all PoW and PoS cryptocurrencies to determine if the previously identified significant determinants retain their significance when considering all cryptocurrencies collectively. The results suggest shared determinants influencing both PoW and PoS cryptocurrency return volatilities. These determinants are size effect, momentum effect, market risk premium, scarcity effect, and investor attention.</p
Crossing the Equator: Reconsidering a New Cross-cultural Aesthetic Paradigm of Screen-based Immersion of Landscape (Mountains and Water)
No full textCountries have diverse cultures, with some being multicultural, employing a variety of aesthetic understandings and artistic forms. Contemporary aesthetics, as a paradigm of appreciation, challenge the constraints imposed by different cultures and traditions. Australian culture is enriched by the diversity and combination of immigrant cultures and exhibits more distinct characteristics. My research aims to explore a contemporary creative approach that incorporates Chinese aesthetic characteristics into contemporary Australian perspectives of landscape.
The aim of my research is to merge understandings of common implications of experimental video practices in China and Australia, with the goal of fostering an emerging aesthetic that bridges intercultural projects. Thus, identifying a method to convey this concept is crucial. The significance of this research lies in the constantly developing relationship between China and Australia across arts-based domains. I intend to analyse innovative forms of cinematic and video art language that blend Australian and Chinese aesthetics, aiming to create original video artworks. This endeavour seeks to introduce a new aesthetic approach and paradigm within the field of visual arts.
The research questions guiding this study are:
1. How might Chinese shanshui aesthetics be demonstrated through contemporary digital technologies?
2. How can blending shanshui aesthetic paradigms with contemporary Australian perspectives of landscape through video practices contribute to the development of novel cross-cultural aesthetics?
This project commences with an examination of experimental video art in Australia and China, introducing a new aesthetic paradigm into Australian video art. It investigates practices in this field that might be integrated to develop new approaches for making screen-based immersions in landscape. A new practice-led creation involves the combination of many elements, including visual art, sonic art, and panoramic view, and integrates with contemporary digital technologies such as Augmented Reality (AR) and Artificial Intelligence (AI).
My methodology integrates a combination of fieldwork, site visits, studio painting experiments, and digital editing, creating a video on a river theme to bond my personal experiences. I delve into these methods in more detail in the separate projects.
Project 1: A Panorama of Blue-green Victorian Landscape. This project investigates and experiments with ways in which AR can offer exclusive insights when combined with a digital panorama. I use the software Mental Canvas to build a smartphone application through which audiences can watch the animation. The primary finding of this study is the significance of immersing oneself in Victorian landscape, revealing how deeply engaging with it transcends the limitations of time and space.
Project 2: Inner Golden Water River (Beijing) meets Yarra River (Melbourne). Through practice-led research, I apply Chinese shanshui aesthetics to express the concept of Being Water (上善若水). The supreme virtue for a human being is like the nature of water, which covers all things. This metaphor declares that people can live without pursuing fame and fortune, embodying water’s flexibility, and its capacity to harmonise with the diverse ideologies and dispositions of the world. I use AI platforms to generate digital images and videos based on my creative ideas and paintings. The secondary finding of this study is the importance of connecting with water and urbanisation across different cultures, highlighting how experiencing different scenes can enhance this connection.
The conclusion explores new possibilities for cross-cultural aesthetics, highlighting the potential for innovative artistic expressions that merge diverse cultural perspectives and traditions.</p
Growth Areas Liveability Scorecard for Brisbane
No full textThis report is the first series of Growth Areas Liveability Scorecard
Reports developed in partnership with the National Growth Areas
Alliance. The Growth Area Liveability Scorecards have been
developed for the capital cities of Adelaide, Brisbane, Melbourne,
Sydney and Perth include indicators and maps from the
Australian Urban Observatory measuring the liveability of 21
Australian cities. The Scorecards focus on the fastest growing
Local Government Areas located in outer metropolitan and
peri-urban regions of Australia’s five largest capital cities. The
Growth Area Liveability Scorecards identify differences between
Growth Areas and Non-Growth Areas across Australian capital
cities. Results are based on previous City Liveability Scorecards
developed by the Australian Urban Observatory @ RMIT University
and are based on 2021 indicator results.
More detailed neighbourhood, suburb, and Local Government
Area results across Australian cities are available online at
auo.org.au.</p
Evaluating public a priori acceptance of autonomous modular transit using an extended unified theory of acceptance and use of technology model
No full textThis study aims to assess the public acceptance of Autonomous Modular Transit (AMT) and identify key factors influencing people's intentions regarding the future use of AMT. While the integration of autonomy and modularity in transport systems has gained attention in recent years among researchers, the study of AMT acceptance is non-existent in the literature. To address this research gap, the study proposes an extended Unified Theory of Acceptance and Use of Technology (UTAUT2) model to explore public acceptance of AMT. It integrates the original model's constructs with two additional factors: trust and perceived green usefulness, while also investigating the role of public transport usage behavior in intention. Data were collected through an online survey involving 1662 participants from different cities in Iran. Structural equation modelling was used to evaluate the conceptual model. Multiple t-tests and ANOVA tests were conducted to evaluate the effects of public transport usage behavior and demographics on the model's constructs. The results showed that the majority of respondents showed their acceptance toward using AMT when available despite their limited prior knowledge about the system. Perceived usefulness was the strongest predictor of intention, followed by social influence and hedonic motivations. Although the COVID-19 pandemic significantly reduced the number of public transport (PT) regular users, this group showed a higher intention to use AMT compared to PT non-regular users. Furthermore, respondents aged over 60 years stated a lower intention to use AMT than their younger counterparts. Given that the mass adoption of AMT depends on public acceptance, this study is expected to serve as a benchmark for comparing countries with similar cultural contexts