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(2020)ThesisThe river water quality plays an important role in our daily life, with rivers providing fresh drinking water and water for industry and agriculture. However, water quality could be affected by the future impacts of climate change on water temperature because of global warming and on streamflow because of changes in precipitation. Nutrients in runoff from farmland and towns will also affect water quality, and may lead to algal blooms. The water-quality model QUAL2K was chosen as the numerical modelling tool to study water quality along the Shoalhaven River, NSW, Australia, in response to changes in the climate and in nutrients in runoff. Three independent variables, air temperature and streamflow representing climate change, and nutrient runoff were varied in eight hypothetical scenarios to determine their impact on water quality, represented by water temperature, and dissolved-oxygen, nitrogen, phosphorus and phytoplankton concentrations. An increase in air temperature by up to 2℃ resulted in an increase in water temperature and phytoplankton concentration, and a decrease in dissolved-oxygen concentration; these changes were more significant when the streamflow was also decreased by 35%. Reducing nutrient runoff reduced the nitrogen and phosphorus concentrations, resulting in a significant increase in the dissolved-oxygen concentration. This study quantifies some of the impacts of climate change and nutrient pollution on water quality and phytoplankton concentration in the Shoalhaven River, providing scientific guidance for managing water quality and algal blooms in future climate-change and nutrient-pollution scenarios.
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(2022)ThesisThere has been a global increase in the research and development of military hypersonic technology. Thermal directed-energy systems have been identified as a capability to defend against hypersonic threats. A numerical and experimental methodology for studying the effects of thermal energy deposition on representative hypersonic panels is presented. This thesis contains four sections, (i) theory and implementation of a first-order, fast, transient thermal-structural code: "Rapid Engineering Determination of Heating over a Trajectory'' (REDHOT), (ii) thermal-structural results from two case studies using REDHOT with energy deposition, (iii) development of an experimental technique to create and measure adverse thermal-structural failure caused by energy deposition, (iv) experimental validation of the technique. The first-order thermal structural code uses the reference-enthalpy method and two-dimensional conduction to calculate the thermal state of a representative hypersonic panel. Thermal stresses are calculated analytically with linear plate theory and non-linear finite element analysis simulation. Numerical results using the HyperX and HEXAFLY-INT trajectory as case studies are presented. REDHOT calculated nominal temperatures without energy deposition are within 1-10% of reported results in literature, acceptable for the first-order analysis in this thesis. Energy deposition is observed to have a greater effect on the skin panel when it is already thermally and aerodynamically loaded. The panel is more structurally compromised for energy pulses of long duration, of higher magnitude and/or applied at times of strong aerodynamic loading. The experimental technique builds on existing electro-resistive heating techniques used for wind tunnel testing. Parametric studies were conducted to understand the design space and determine optimal panel thicknesses and direct-current application to maximise thermal-structural effects. A method to measure the induced thermal strain using digital image correlation was developed. To validate the experimental technique, a model with a 120mm by 80mm graphite panel with varying thicknesses was designed and tested on the bench. For the thinnest available plate, and a direct-current power supply of 350A material failure was not observed. Finite element modelling of the experimental conditions was conducted. Recorded temperatures were approximately within 9% of simulated results. Measured thermal strain was within 0.05% of simulated material.
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(2020)ThesisCyberbullying is a very damaging aspect of social media platforms. This thesis explores how cyberbullying avoidance behaviours can be encouraged using persuasive design techniques in combination with real-time automated cyberbullying detection and design attributes that would be persuasive in deciding not to cyberbully. Close attention is paid to automatic detection using machine learning techniques and issues identified within the literature with machine learning techniques that use balanced versus unbalanced datasets. This thesis finds that neural networks were able to detect cyberbullying posts ac- curately in unbalanced datasets. Additionally, and in combination with more traditional classifier algorithms deployed in a hybrid solution, posts could be triaged faster and de- tection would work in a real-world scenario. This thesis then considers how automated detection of cyberbullying could aid a “messagebot” to give the appearance of monitoring cyberbullying in real-time and then derives a cyberbullying prevention model.
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(2020)ThesisIn this thesis, a novel framework has been developed to quantify the radiation from tropical cyclones (TCs) in shortwave (SW) and longwave (LW) portions of the optical spectrum. The framework includes two stages: segmentation of TC clouds and calculation of the radiation attenuation due to TC clouds. The segmentation task was accomplished by an algorithm which takes a time series of brightness temperature images of tropical cyclones and uses image processing techniques to acquire segmentation for each image. The radiation was calculated by combining the segmentations with a radiation dataset provided by the Cloud and Earth's Radiant Energy System dataset via a coordinate-matching scheme due to their difference in resolution. The framework was used to investigate some preliminary results as part of a hypothesis that links the radiation due to TC and climate change. The framework was successfully implemented to analyse TCs' radiation in 2016, at the regional and global scales. Results show that TCs contributed a total of 21.25 TW of radiation to the global upwelling radiation, which is attributable by 152.27 TW in reflected shortwave radiative contribution and 131.02 TW in the emitted longwave radiative reduction. Although the radiation contribution from TCs was confirmed to be of the right order of magnitude to affect the Earth's Energy Balance, its impact on the balance would depend on how much the contribution varies, observed throughout a sufficient period of time. While this inquiry would require another comprehensive research, the framework remains the main contribution of the thesis. The framework has laid an important foundation for future work on TC radiation in general and for further insights into the impacts of TCs on climate change in particular.
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(2022)ThesisChina does not have formal alliances; rather, it has partnerships. But what is the significance of ‘partnerships’? How are they defined and used by Beijing? How different are they from traditional alliances? Despite claims that China’s expanding network of partnerships has enabled the growth of its influence around the world, the topic of Chinese partnerships itself remains understudied—a gap which this thesis seeks to fill. This thesis examines how China leverages its partnerships (huoban) to achieve the overarching foreign-policy goal of bringing about ‘national rejuvenation’ and, in so doing, increase external support for its position as a global power. Here, the thesis sheds light on the effectiveness of Chinese efforts to deploy the language of partnership to persuade other countries to align their foreign-policy rhetoric and practice with the Chinese policy agenda. Acknowledging that the ways in which China persuades or compels other states to support its objectives in both rhetoric and practice are crucial to understanding what kind of global power China will be once it achieves national rejuvenation, this thesis identifies the concept of partnership as a pivotal component of Beijing’s international engagement strategy to signal its interests and, ultimately, as a means to rejuvenate the nation. Using a discourse-historical approach, the thesis draws on English and Chinese language sources to analyse China’s use of partnerships in its bilateral engagements and the practical implications of doing so. It argues that the formalised language and ‘considered hierarchy’ of Chinese partnerships reflect how China has sought to leverage these as a diplomatic tool to attain specific foreign-policy objectives and outcomes. To demonstrate this, the thesis analyses two thematic issues—the Taiwan question and the Belt and Road Initiative—across two country cases of Papua New Guinea (PNG) and Fiji. In exploring how Beijing has persuaded PNG and Fiji to adopt policy language and actions that align with and support Chinese foreign-policy objectives, this thesis finds that Beijing has used the language of partnership and, specifically, the economic and aid incentives offered by an upgraded partnership to signal the behaviours expected of its partner countries and delineate the appropriate discursive parameters for its bilateral relationships. Doing so contributes to streamlining partner countries’ acceptance of, and conformance with, Beijing’s positions on key—oftentimes controversial—issues directly pertaining to its national interests.
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(2022)ThesisThis thesis addresses a real power sharing method of electronically interfaced dis tributed generation (DG) units in the context of a multiple-DG micro-grid system where there is no synchronous generator. The emphasis is primarily on electronically interfaced DG (EI-DG) units like DFIG connected wind generator, PV system and battery storage. In this dissertation, the main goal is designing and testing of a new algorithm to distribute the load changes among intermittent distributed generators according to their power ratings. The power sharing by the commercial distributed energy resource (CDER) unit is mainly based on locally measured signals without communications. In the controller, proposed in this thesis, the voltage source inverter of the battery energy storage system (BESS) changes the frequency of the network with the change in load demand. The real power of each CDER unit is controlled based on a frequency-droop characteristic and a complimentary frequency restoration strategy. A systematic approach to develop a small-signal dynamic model of a multiple-DG micro grid, with a real power management method, is also presented. The model is used to investigate the sensitivity of the design to the changes in parameters and operatingpoint and to optimize performance of the micro grid system. Finally, the performance of the proposed algorithm is tested on a benchmark medium voltage network.
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(2020)ThesisRobert Putnam has famously noted in his two-level game theory that a country’s domestic and international spheres are interacted and a country’s foreign policy could be driven by domestic politics. My dissertation addresses the question of what the implications of Vietnam’s and China’s current domestic challenges are for their foreign policy in the South China Sea (SCS). The SCS dispute is contemporary, including competing territorial sovereignty claims and Vietnam and China are the two largest claimants. I articulate the countries’ domestic challenges in three domains namely economic growth, regime legitimacy, controlling territory and sovereignty and analyse how these issues impact on the countries’ SCS policy. I propose that Beijing’s policy to keep the SCS situation under control and to contain any intensifying provocations of certain neighbouring countries, including Vietnam is a result of China’s efforts in managing current domestic challenges. I argue that the Communist Party of Vietnam’s (CPV) maritime strategy is to sustain economic growth to address their current domestic issues. This created a dilemma for Vietnam as they could only implement the maritime strategy without any coercion in the SCS, and consequently, there were limitations in the CPV’s formation of SCS policies against China. My dissertation expands the range of study of China’s and Vietnam’s SCS policies by applying the integration between domestic and international domains to explain the drivers of the countries’ SCS policies. I conclude with a discussion of on-going challenges facing both China and Vietnam in developing effective SCS strategy and recommend further research on multilateral management regime in the SCS and Vietnam’s military modernisation for deterring China.
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(2021)ThesisDisasters are hazards that damage the human environment. Disasters have had significant costs in the past and their financial impact is expected to increase in the future. Community Resilience (CR) is the ability of a community to resist, absorb, accommodate and recover from disasters (UNISDR 2015). The methods developed to evaluate CR are broad and varied, however all seek to enhance a community’s understanding of its abilities. By better understanding a CR, decision makers can make better informed decisions on how and where to apply limited resources. Emergencies and natural hazards have seen the extensive application of information communication technologies (ICT). The application of ICT in disasters includes their use to facilitate the exchange of information between emergency management agencies (EMA) and the public. To date, academic research in this field has focused on how social media (SM) platforms and data mining may be used to enhance EMA situational awareness during disasters and their ability to detect and respond to emerging disasters (Stieglitz, Mirbabaie, Fromm, et al. 2018). However, research into using analysis of social media within CR evaluation has been limited to date. This use of social media analysis for community resilience evaluation can be used to inform decision making in pre-event phases. This thesis seeks to explore whether the analysis of SM data may contribute to the evaluation of CR. To do this, it reviews existing CR evaluation frameworks and identifies possible SM variables for employment in CR evaluation. Subsequently, it reports on a case study that applies SM analysis to CR evaluation of three communities in Australia (the City of Lismore, Western Plains Regional Council, and Queanbeyan-Palerang Regional Council). This case study employs two Indicators from SM analysis (EMA influence and engagement within a community, and active participation of users with Institutions) to evaluate the Institutions Domain of CR. The performance of these Indicators are compared to the overall performance of the Institutions Domain of the Baseline Resilience Indicators for Communities (BRIC) (Cutter, Ash, and Emrich 2014) evaluation framework in the same communities and the performance of the communities in the Australian Natural Disaster Resilience Index (ANDRI) CR evaluation framework (Parsons et al. 2016). The results show that SM analysis may provide a method to enhance CR evaluation through the integration of SM Indicators.
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(2021)ThesisRapid, globalised power shifts, technological advances, and increasingly interconnected, ungoverned communications networks have resulted in the rise of asymmetric grey zone threats. The lines are now blurred between political, civil, and military information environments. The rise of influence activities is the new ‘sharp power’ in information warfare (the iWar). Western democracies are already at war in the information domain and are being out-communicated by their adversaries. Building on the commentary surrounding this contemporary threat, and based on a review of the literature across three academic disciplines of: Systems Thinking, Influence, and Cognitive Theory; this study aimed to investigate solutions for improving Australia’s influence effectiveness in the iWar. This study asked how systems thinking can offer an effective approach to holistically understanding complex social systems in the iWar; as well as asking why understanding both successful influencing strategies and psychological cognitive theories is central to analysing those system behaviours. To answer the aim, a systems thinking methodology was employed to compare two contrasting case studies to determine their respective influencing effectiveness. The successful case system comprising the terrorist group ISIS was compared and contrasted with the unsuccessful case system of Hillary Clinton’s 2016 election campaign – using a single stock of influence to determine relevant reinforcing and balancing feedback. The findings validated the utility of systems thinking analysis for holistically understanding complex iWar systems, and revealed why the case systems were effective or not in raising influence stocks, dominating the iWar, and manipulating cognitive behaviour. The results highlighted the configurational, behavioural, and causal factors contributing to influence effectiveness and were summarised into key themes for each of the research disciplines, e.g. a successful system has control, resilience, a centrality of focus, and strong communications links. Based on the results, this study concluded with a number of recommendations including: having a resonant strategic narrative and cohesive communications strategy, turning democratic vulnerabilities into strengths, adopting systems thinking approaches, enhancing critical thinking, exploiting civilian capabilities, and regaining control over the media. Further research is required across all three academic disciplines to enhance understanding and resilience, refine approaches, and improve the effectiveness of Australia’s future iWar strategy.
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(2020)ThesisInnovation is an economic force and an essential organisational function in need of its management. ISO56002: Innovation Management System Standard (IMSS) is a new global standard that provides guidelines to manage innovation. Within the innovation process, its Fuzzy Front-end (FFE) is fluid and complex yet essential for the success of innovation. Start-ups, are essential within the entrepreneurial economy and rely on both innovativeness and their leanness. With the fluidity of FFE and desired leanness of start-ups as its backdrop, the thesis assesses the applicability of IMSS in managing FFE of innovation for start-ups. This is done using two variables, one measuring the perception of CEOs/founders of selected start-ups of the applicability of the IMSS and the second measuring the actual use of IMSS by start-ups. A representation of FFE in IMSS, which does not exist, was developed, Structured interviews were used to collect data which was then analysed to comment on the applicability of the IMSS in this context. This thesis found that IMSS was perceived to be applicable and was mostly used by start-ups in managing FFE. The thesis also found that the applicability of IMSS varied depending on the maturity of the start-ups. The thesis found the perception of applicability to be higher than the actual use of IMSS. The thesis contributes by providing an early insight to start-up founders/CEOs, consultants and practitioners on IMSS, its applicability and adoption. The thesis also provides a representation of FFE within IMSS. Contributions from the thesis may also be used as a foundation for future research.