UNSW Canberra

Publication Search Results

Now showing 1 - 10 of 16
  • (2022) Xie, Yuekai
    Thesis
    The increase in waste disposal increases the demand for better design, construction, operation and management of the landfills. A common method to accelerate the decomposition, stabilization and settlement of municipal solid wastes (MSWs) is leachate recirculation. However, slope failure occurs due to the poor design and management of the recirculation and gas collection systems, together with the change in the geotechnical properties of MSWs due to decomposition. Based on the field compositions at a working cell in Mugga Lane Landfill, ACT, Australia, a series of experiments have been conducted to study the effects of leachate exposure on the geotechnical properties of MSWs with different compositions. The experimental programs include compaction, saturated hydraulic conductivity, direct shear, consolidated undrained triaxial shear and one-dimensional consolidation. Following this, fresh waste samples with different compositions were prepared in the simulators and recirculated with water or leachate to enhance the biodegradation. The samples with the same dry unit weights but different degrees of biodegradation (DOB) were tested to address the effects of decomposition on the geotechnical properties of the MSWs. Despite of the change in the composition and particle sizes, the variation in the leachate properties significantly affects the geotechnical properties of the MSWs. Three small laboratory scale and one larger laboratory scale, and four field scale bioreactors were set up in the laboratory or landfill site. The objectives are to investigate the effects of initial compaction, recirculation liquids and rates, loading levels and environmental temperatures on the long-term physical, mechanical and biochemical behaviours of the MSWs. The measured and analyzed properties include the settlement, initial creep, bio-compression and residual creep ratios, quantity and quality of leachate generation, rate and concentration of methane generation. A new equation was developed to capture the change in the methane generation rate with time. Further experiments were conducted to evaluate the water retention curves (WRCs) of MSWs under different degrees of biodegradation, dry unit weights and paper contents. Fresh MSW samples and soil-paper mixture were compacted to different initial dry unit weights and then decomposed for different periods to the same dry unit weight before testing. It was found that, in addition to dry unit weights of MSW, the effects of decomposition and paper contents on the unsaturated properties of the MSWs depend on the balance between the percentages of biodegradable and highly decomposed components. Two settlement profilers were installed in the landfill site to obtain the settlement of an MSW lift in a working cell of the landfill site. A global navigation satellite monitoring system was installed to monitor the settlement of three closed landfill cells. A settlement model was developed based on the change in the solid, liquid and gas phases of MSWs due to decomposition. The proposed settlement model was validated with the results from the laboratory and field scale bioreactors and in-situ monitoring data.

  • (2022) Nguyen, Tung
    Thesis
    Transparency ensures that the decision-making logic used by autonomous agents is available in a form comprehensible to human teammates. It enhances a system's performance, reliability and trustworthiness. Transparency in human-autonomy teaming is a key success factor in the communication between humans and autonomous agents. This thesis focuses on the problem of knowledge transfer between two neural network (NN) agents in a swarm-guidance task in the presence of a human observer. A novel three-module knowledge transfer framework is proposed to interpret non-symbolic knowledge of communicative autonomous agents into a transparent human-friendly form. The knowledge interpretation module transforms the NN into a rule-based knowledge representation. The relevant knowledge is then chosen by a knowledge selection module to transfer it to the other agent. Finally, the knowledge fusion module combines the newly incoming knowledge with the receiver agent's existing knowledge. Two algorithms are introduced to transform NNs into a rule-based knowledge representation. The first algorithm, the Exact-Convertible Decision Tree (EC-DT), rewrites the relationships between nodes and weights of the NN into a multivariate decision tree. The second algorithm, the Extended C-Net, leverages the training data to learn the association between the NN's nodes at the final hidden layer and the outputs and then uses recursive back-projections to derive the rules regulating input-output relationships. Performance is assessed using three measures: fidelity, compactness and transparency. EC-DT has higher fidelity, while Extended C-Net produces more compact rule sets. The fusion module then evaluates the effectiveness of transmitted rule-based knowledge in new environments. The rule-based representation is projected back into forms that can be integrated with the NN representation at the receiver agent's end. A retraining strategy, Priority on Weak State Areas (PoWSA), is introduced to help speed up the learning process in novel scenarios. Analyses of the proposed methodology in a swarm-guidance problem show higher training stability and chances of success in return for a slight increase in computational costs. The framework provides a more transparent knowledge representation that could be visualised to complement the verbal rule-based representation.

  • (2022) Chen, Wenxin
    Thesis
    Projects account for 20%–40% of all economic activity (Schoper et al., 2018). They are the main vehicle for achieving organizational strategies (Kwak & Anbari, 2009). Despite this, the rates of project success remain low. Many researchers point to project governance as a key factor in improving project success (Crawford et al., 2008). In that light, a key focus in this thesis is the role of project sponsors in project governance, particularly their relationships with project managers and project teams by way of formal and informal governance mechanisms. However, little is understood about the interplay between two major types of governance mechanisms, formal and informal, regarded as either substitutes or complements. This lack of understanding can be attributed to two factors: (1) a lack of a holistic and dynamic perspective in developing project governance mechanisms and (2) little consideration of project sponsors’ cognitive barriers in implementing the governance mechanisms. This thesis draws on Yin-Yang and mindfulness theories to explore whether and how an appropriate balance can be established between complementary yet conflicting project governance mechanisms, with a view to project performance. Three Chinese case studies were conducted to verify the usefulness of Yin-Yang principles in guiding the interplay of formal and informal governance mechanisms and the importance of the project sponsor’s mindfulness in balancing the governance mechanisms. The case studies suggest this approach may enhance the project’s performance.

  • (2022) As'ham, Khalil
    Thesis
    Light-matter interaction within a strong coupling regime has attracted much attention because of its potential applications in quantum manipulation, Bose−Einstein condensation, optical transistors, coherent emission or absorption, photovoltaics, ultrafast optical switching, sensing, low-threshold lasers, quantum fluid of light and all-optical logic devices. However, conventional materials used in strong coupling suffer from several challenges, as follows: low working temperature, small binding energy, low-quality factor and challenging fabrication. To overcome these limitations, transition metal dichalcogenides (TMDCs) and 2D lead halide perovskite materials are used to achieve a strong coupling regime between optical and polariton modes. This thesis initially reviews previous studies that used TMDCs or perovskite materials in a strong coupling regime. Owing to TMDCs’ optical properties, several studies reported the strong coupling between exciton and optical cavities. However, current structures face many challenges, including difficulties in fabrication and the associated cost increase. The strong coupling between exciton in TMDCs monolayer, plasmonic resonance in silver and anapole mode in Silicon nanodisk was analysed at room temperature and normal incident. This nanostructure provides large Rabi splitting accompanied by a giant field enhancement, thereby paving the way for the creation of exciton-polariton devices. Although previous studies used metallic nanocavities to excite plasmonic resonances that offered a small mode volume and strongly coupled them with exciton in TMDCs, damping losses in metals degraded the performance of exciton-polariton systems. Consequently, researchers used dielectric materials as an alternative to plasmonic materials to observe a strong coupling regime. However, exciton-polariton devices that use dielectric materials suffer from large mode volumes. This thesis explores the strong coupling between hybrid resonance and exciton in hybrid dielectric-metallic nanostructure and TMDC monolayer by using metallic and dielectric materials that include small mode volume low losses. Another material with potential for strong coupling is lead-halide perovskite. Lead halide perovskite materials have a larger binding energy at room temperature compared with conventional materials. Thus, the strong coupling between exciton of perovskite and photonic cavity has been demonstrated in different platforms, such as plasmonic nanocavity and distributed Bragg reflector-based microcavity. The former suffers from large intrinsic loss due to the nature of noble metals, and the latter may involve a complex fabrication process. In recent years, researchers have also used a guided-mode resonance supported by a photonic crystal slab to achieve exciton-polariton in perovskite metasurface. In this thesis, the strong coupling between Mie resonances and exciton is explored at room temperature without resorting to other photonic cavities. Finally, at the end of this thesis, the future perspective and a summary of this research's main results are presented.

  • (2022) Maranan, Noahlyn
    Thesis
    The 2016 vice-presidential election in the Philippines was contested on Facebook, the nation’s most prominent social media platform. Among the contenders was Ferdinand ‘Bongbong’ Marcos, son of former president Ferdinand Marcos Sr, who ruled between 1965 and 1986. Memes played a significant role in the election. They potentially enriched participatory engagement and information dissemination to a broader public. Through them, opposing camps worked through different versions of the Philippines’ past, present, and future. This case presents a novel opportunity to contribute to the growing scholarly debate about the relationship between social media and democratic politics. This study asks, “Can social media contribute to strengthening democracy in the Philippines?” It approaches this question through a conceptual framework that integrates work on democracy and political memory while also taking seriously the propensity of social media to be enlisted in information campaigns of a propagandist nature. Having analysed a sample of Facebook memes for their form and content, the study comes to an ambivalent conclusion. As immensely pliable and flexible texts, created and circulated with ease, the thesis finds that memes play a dual role in democratic politics. In the 2016 Philippine election, they (a) allowed for the inclusion of competing perspectives, narratives, and voices about Marcos Sr’s past regime and his son’s electoral bid. Rational and passionate voices, as one would expect from models of deliberative and agonistic democracy, were visible in this study. Enabled by digital platforms, memes became an important medium for the creative, potentially deliberative, and agonistic (if not outwardly antagonistic) articulation of sidelined memories about the regime of Marcos Sr. At the same time, (b) memes served as instruments for persuasive networked influence. While this may seem contrary to democratic communication, such propagandistic communication carries the potential to enrich reasoned argumentations in the broader public sphere when viewed from the lens of the wider literature on deliberative democracy. This potential, however, also depends on other factors, which include the techno-discursive platform in which propagandistic content circulates and the characteristics of the electorate.

  • (2022) Shivadas, Priyanka
    Thesis
    This thesis juxtaposes Indigenous Australian literature and Adivasi/tribal literature—two self-governing bodies of Indigenous literature differently situated: one in an Anglophone, white settler-nation in the Pacific region and the other in a non-Anglophone, postcolonial nation-state in Asia. Studies exploring critical connections between Indigenous writing from Australia and Adivasi/tribal writing from India are rare. A considerable amount of scholarship brings together the literatures of Indigenous Australians, Māori, Native American and First Nations peoples of Canada, who share much in their responses to European settler-colonialism, but little ventures into comparative study of the literatures of the Indigenous peoples of Australia and India. This thesis is guided by Native American scholar Chadwick Allen’s trans-Indigenous methodologies, which open up possibilities for global Indigenous literary studies by building from specificities and across, through and beyond differences in diverse Indigenous contexts. Beginning from a place of accepted difference and distance, this thesis thus seeks connection and comparability, framing similarities through identifying a shared set of issues/themes and genres. This study finds the following literary and thematic concerns are shared between Indigenous Australian and Adivasi/tribal writing: (a) land and labour, (b) bilanguaging, (c) editorial negotiations in cross-cultural, collaborative life writing, (d) gender and sexuality as sites of decolonial critique, and (e) responses to over-policing and death in police custody. These shared concerns structure and organise the thesis. They also form the basis for trans-Indigenous analysis of a selection of illuminating case studies. In each case, analysis seeks to yield Indigenous-centred, productive readings of juxtaposed Indigenous Australian and Adivasi/tribal texts, resulting from the tension generated between their distinctiveness and shared (post)colonial concerns. Ultimately, this study disrupts familiar patterns of comparison and encourages new models of critical thought in global Indigenous literary studies.

  • (2022) Schwirtlich, Anne-Marie
    Thesis
    Following the 1857-1858 Mutiny and its expression of Indian hostility to British rule, the British response included the formal transition of power, in 1858, from the British East India Company to the Crown. A significant increase in the size of the British population - driven by an increase in the number of British soldiers stationed in India - accompanied this shift in governance. The Mutiny, for the first time, required British authorities and the British public to deal with a significant number of British widows. These women were a stark visual reminder of personal and national vulnerability and of Britain's military failure. The subsequent four decades saw the consolidation of, and the growth in opposition to, British authority in India, and the fashioning of Britain's imperial narrative. Articulations of the purpose of British rule of India focused on Britain's advanced status, its strength (economically, legally, politically, educationally, and morally), and on the benefits India, in turn, would derive from British rule. The success of the narrative required the British in India to exemplify this purpose, status, and strength. This thesis argues that British women widowed in India between 1860 and 1900 were emblematic of the vulnerability, failure, and cost of Britain's presence in India. The fact of their widowhood and their behaviour while in India could tarnish, if not threaten, Britain's narrative of superiority by their critique of British rule, and by their indigence, lack of industry or immorality. An analysis is made of the cultural expectations of widows and the manner in which fiction, advice manuals, consolatory literature and policy marked the boundaries of acceptable behaviour and set the parameters to 'manage' widows. This is complemented by close research of the experiences of a cohort of 260 British women widowed in India between 1860 and 1900. The exploration of the interplay between societal expectations and the ways in which widows accepted, accommodated, adapted, or exploited these expectations illuminates our understanding of gender in British imperialism. This study concludes that while a few widows openly challenged societal expectations and conventions, or simply operated outside them feeling little obligation to model imperial behaviour, most widows found elements of the conventions sufficiently useful and elastic to forge lives of purpose and meaning.

  • (2022) Taher, Toiaba
    Thesis
    Participatory conservation embraces the idea that nature and people can, and must, work together to manage biodiversity sustainably. Significant live examples—such as that of the Sundarbans mangroves in Bangladesh—suggest that layers of complexity underpin ideas of participatory conservation, often confounding its goals to produce positive outcomes for both nature and people. The Sundarbans of Bangladesh, part of the world’s largest mangrove forest, faces several human-induced challenges, including overharvesting of non-timber forest products and expansion of the commercial shrimp industry. Since 2010, a comprehensive plan has been in place to protect the forest and the 76 communities living there, following the principles of co-management—one of the early participatory approaches in conservation. However, outcomes from the strategies implemented as part of this plan remain unclear. I applied an interdisciplinary mixed-methods ethnographic methodology with an interpretative constructivist perspective to comprehensively evaluate the practised participatory conservation in the Bangladesh Sundarbans. This research is the first to conduct a detailed policy evaluation related to the Bangladesh Sundarbans and its local communities by considering the Kalinchi community as a single case study. Analysis of economic, social, and environmental policies, land use land cover changes, and income analysis are used to examine the appropriateness of practised conservation in this mangrove. This thesis also provides the first-ever detailed qualitative evaluation of participation practised under the co-management arrangements in the Bangladesh Sundarbans, combining the selected community’s lived experiences with the policy administrators’ and practitioners’ perceptions. The empirical evidence from this research suggests that a limited consideration of historical and institutional contexts in conservation planning has restricted the possibility of success. Feelings of negativity and disenchantment expressed by the Kalinchi community indicate that the enabling factors of effective participatory conservation – namely, the highest degrees of engagement and empowerment – were neither enacted nor achieved in the Bangladesh Sundarbans. While the motivations of policy administrators might have been well-intentioned, their assumptions that appeared to have been brought to the processes of participatory conservation saw policy practitioners label the communities living in the Sundarbans as the problem. Tokenistic participation was performed in exchange for the communities’ conservation compliance rather than to facilitate genuine engagement on how they interact with this mangrove ecosystem and what might be altered or initiated to improve the forest and its people’s wellbeing. The research ultimately shows that positive implementation of participatory conservation relies on the motives and practices of decision-makers and their active, nuanced and balanced consideration of the social and political contexts confronting local communities. Until this happens, participatory conservation is doomed to fail in delivering its promises. It is hoped that lessons from this thesis will deliver evidence and provide inspiration for what might be able to be achieved for the next phase of conservation in the Sundarbans and elsewhere.

  • (2022) Reza, Wasim
    Thesis
    In recent years, the use of hybrid structures in the construction industry has increased significantly for various reasons, the most important of which are concerns about environmental sustainability and economic benefits. The present study is a part of a comprehensive research project associated with the development of hybrid structural systems. More precisely, this thesis investigates the structural performance of a hybrid timber-steel beams with web openings subjected to bending. The beam consists of an elongated thin galvanised steel web with press-formed stiffening ribs and flanges made of Laminated Veneer Lumber (LVL) fixed by steel nails to each side of the continuous steel web. A series of laboratory experiments were carried out to analyse the structural performance of this beam. First, a series of four-point bending tests were conducted in order to assess its flexural behaviour and load-carrying capacity, as well as to identify the failure mechanisms. Afterwards, a series of standardised tests were also performed to obtain the respective mechanical characteristics of the wood (LVL) and the steel used to make the hybrid beam. In the second phase, a three-dimensional finite element model of the beam was developed and verified with experimental results, with good agreement. It was developed with the aim of understanding all the stages of the failure modes and the interaction between different timber and steel parts. Furthermore, the FE model was used to carry out a parametric study to experiment with different configurations of hybrid beams. Finally, to facilitate the preliminary design of the beam, a closed-form analytical solution was formulated to obtain the ultimate load capacity and the effective bending stiffness with the load-displacement response of the beam. The closed-formed solution results were compared and verified with the experimental results as well as with the numerical results from the parametric study of different variations of the hybrid timber steel beam with good agreement. To conclude, it was found that in order to exhibit ductile response, the steel web must be relatively thin and elongated so that it fails first in a ductile manner before timber cracking, a behaviour similar to that of an under-reinforced concrete beam. On the other hand, a thin and extended steel web causes lateral instability and premature failure. Consequently, lateral supports are required to prevent lateral instability and obtain the true load-carrying capacity of the hybrid beam.

  • (2022) Sun, Shuyun
    Thesis
    Despite recognition that using digital technology contributes to business growth, entrepreneurship research lacks a complete picture of how digital (technology) users become entrepreneurs. The primary goal of this study is, therefore, to understand the context, process and drivers of digital-user entrepreneurs. Specifically, this study identifies three literature gaps. First, many scholars theorise digital technology as an entrepreneurial environment. However, this perspective overshadows an alternative explanation for entrepreneurial success: actor agency. This study integrates the digital technology perspective and actor agency to explore the role social media plays in enabling its users to become entrepreneurs. Second, while there are some studies on social media-based businesses, few consider the emergence of social media user entrepreneurs. To address this issue, the present study explores the process social media users engage in to become entrepreneurs. Finally, few studies investigate the drivers of social media user entrepreneurs. To address this gap, the study explores why individuals use social media to become influencer entrepreneurs – an emerging type of social media user entrepreneurs. This study draws on a qualitative research methodology that utilises a single embedded case study involving the Chinese social media platform Weibo. The embedded case study examines 12 user journeys as they transition from being social media users into becoming influencers and then influencers into entrepreneurs. The dataset includes two phases of semi-structured interviews with 33 participants, documentary analysis and netnography. The study contributes to digital entrepreneurship research by i) identifying four key enabling mechanisms that characterise a social media platform as an entrepreneurial environment; ii) revealing a process that includes four main stages where individuals strategically use social media to become entrepreneurs; and, iii) uncovering two main drivers that motivate individuals’ engagement with social media along their entrepreneurial journey. The study also provides a practical roadmap for individuals to select the social media platform they will need to use and the strategies they will need to apply to social media use if they wish to become entrepreneurs. It also highlights the drivers that enable or hinder their use of social media to progress in their entrepreneurial journey.