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Novel detection methods for biophotonics sensing
No full textTheoretical thesis.Bibliography: pages 201-209.1. Theoretical introduction -- 2. Smartphone projects -- 3. Fluorescence lifetime imaging using a single photon avalanche diode array – cancer detection based on NADH state -- 4. Conclusions and outlook -- Contribution -- References.The appearance or increase of the fluorescent signal in biological media (whether it is natural autofluorescence or fluorescence of artificially introduced fluorophores) can implicate reaction to specific conditions or diseases. In the first part of this thesis, we explored the possibilities of using smart phone as a point‐of‐care readout device that could replace specialised laboratory equipment like a spectrophotometer or colorimeter at a fraction of the cost. We present two methods that, using the minimum of additions to the phone itself, are sensitive enough to be used in medical diagnostics of clinically relevant conditions including arthritis, cystic fibrosis and acute pancreatitis. In the second part, we developed the highest resolution wide field Fluorescence Lifetime Imaging (FLIM) system based on a Single Photon Avalanche Diode sensor array. The device was capable of detection of sub‐nanosecond lifetimes over an area of about 20cm2, and was able to measure lifetimes of fluorescent signals lower than one photon per pixel per excitation pulse. We proved that the system can reliably distinguish between biologically relevant concentrations of free and bound forms of Nicotinamide Adenine Dinucleotide (NADH). An increment of bound NADH in cells, which is connected to increased cell metabolism, is a proven cancer marker for most cancer types. We characterised the system performance and provided two methods of data analysis appropriate for measurements in a biological tissues or surface tumours. We project that our system is suitable for development into a realtime fluorescence lifetime camera, able to operate at up to 20 Hz with presented performance level.Mode of access: World wide web1 online resource (209 pages) illustrations (some colour
Re-tracing the Tragedy Track
No full textTheoretical thesis.Accompanying radio documentary "Re-tracing the Tragedy Track audio (mp3)" can be found on https://www.abc.net.au/radionational/programs/archived/hindsight/re-tracing-the-tragedy-track/3673122Bibliography: pages 299-309.1. Laying the groundwork: re-tracing the Tragedy Track -- 2. Political, historical and anthropological context for re-tracing the 'Tragedy Track' -- 3. White man's dreaming track -- 4. Digging into the Tragedy Track: conflict and massacre -- 5. Strehlow's wagon: on the road to the Granites and Yuendumu -- 6. The Tragedy Track, cultural studies, postcolonialism and critical discourse -- 7. Audio ethnography and the cultural study of sound: two case studies -- 8. Telling stories with the shapes of time.In the middle of the Great Depression, driven by the stories journalist Ernestine Hill had been filing from Alice Springs, the Packer and Murdoch newspaper organisations funded an expedition to the Tanami Desert in the Northern Territory to determine if these stories of a gold rush had any merit. The Sun-Telegraph Expedition in 1932 drew together an odd group of characters: a journalist working for the Packer organisation, F. E. Baume; a geologist from the University of Adelaide, C. T. Madigan, who later went on to map the Simpson Desert; and Melbourne photographer, Franz Marcard. The three travelled halfway across the Tanami to investigate this so-called 'gold rush'. Baume would later write a book, Tragedy Track: The Story of the Granites (1933), from the journey and investigation; and over one thousand acres of desert - tribal lands and sacred ground of Indigenous land owners - would soon be 'pegged out' by prospectors, then sold as mostly non-existent goldmines. Tales of Indigenous resistance to the prospectors dominated headlines at the time as the possibility of finding gold began to diminish. There were others who ventured here too to establish cattle stations and eventually an 'aboriginal reserve' on this land, which became Yuendumu. The land had been occupied until then and for thousands of years by distinctive Indigenous nations. In this 're-tracing' of the Tragedy Track story, many Indigenous people recall their stories of life on the track: of harsh justice for themselves, their relatives and forbears; the loss of precious water supplies and access to tribal lands. They recall working long hours for meagre rations and the devastating separation from their own children by government appointed so-called 'Protectors'. The Coniston massacre is not a distant memory and remains a wound in this landscape and history This PhD aims to 'write back' then, to the more mainstream stories of discovery and gold rush, and the subduing of the First Nation peoples of this region by government officials and prospectors. It writes back with new critical materials and interpretations of this first media story of the making of a track through the Tanami Desert. In doing so, it also follows the many overlooked or forgotten sidetracks which cross this road's path: these delivering no less significant stories of encounter between Indigenous and white colonisers and even researchers. The PhD and accompanying radio documentary draw here on Indigenous oral histories collected by the author in the region, as well as other historical and anthropological accounts associated with the region's transformation and ultimate settlement and division by the white colonisers. This becomes then a newly annotated history where it may be possible to hear a more critical articulation of this place across time. Explored through the lens of cultural geography, postcolonial theory and the history of Australian anthropology - an historical tracing and re-evaluation of anthropological encounters and 'research' in the Tanami as I sift through the historical evolution of racial discourses applied to Indigenous in this region, for example - a new multi-stranded multi-vocal story is sounded in both the radio documentary and the thesis. This creates, I hope, a new map and even key to the stories of the Tanami1 online resource (xv, 311 pages : map
Novel applications of gravity gradiometry for the detection and monitoring of sequestered CO2
No full textEmpirical thesis.Bibliography: pages 246-275.Chapter One. Introduction -- Chapter Two. Background -- Chapter Three. Simplistic downhole benchmark -- Chapter Four. Regional geological simulation -- Chapter Five. Satellite reservoir monitoring -- Chapter Six. Discussion -- Chapter Seven Conclusion -- References -- Appendices.Carbon Capture and Storage (CCS) is a technique for the reduction of greenhouse gases in the atmosphere, involving the drawdown of atmospheric or emitted CO2, and its sequestration into geological reservoirs. Its effectiveness depends on the immobility of the sequestered fluid, and CCS projects depend critically on remote monitoring to ensure that the sequestered material does not escape into the atmosphere. The monitoring of CCS sites is largely dominated by seismic methods, alongside supplementary techniques such as gravity, electromagnetics, and geochemical monitoring. Hitherto, gravity gradiometry has not been utilised extensively for the monitoring of CCS sites, as an extensive modelling framework and sensitivity analysis, to discern its viability for monitoring CO2 sequestration, has been lacking. The aims of this project are to assess and develop modelling framework for downhole gravity gradiometry, and a method to assess uncertainties in modelled results, and thus the sensitivity of the technique, using a Monte Carlo approach. The approach is applied to a number of existing CCS projects, including the CO2CRC's Otway CCS demonstrator project, to assess the potential of gravity and gravity gradiometry to monitor sequestered reservoir fluids, in both downhole environments, and remotely.The initial phase of this work involved constructing a simple benchmark numerical model of a reservoir density anomaly, and developing a Monte Carlo simulation approach to assess how the density and spatial uncertainties in a geological model relate to the final uncertainties in the modelled response; and ultimately the sensitivity of gravity gradiometry when applied in a downhole setting for the detection of sequestered CO2. In the initial benchmark, the reservoir was modelled as a simple prism, with a density contrast constrained by the Otway project petrophysical logs. Three boreholes were then modelled at varying distances from the centre of mass of the prism. Strong downhole gravity gradient signals were observed surrounding the reservoir prism, with some components of the gradient tensor demonstrating high sensitivity, notably the vertical gradient Gzz which displays a mean signal up to ~80 Eötvös within the centre of the prism, with a standard deviation (SD) of ±~20 Eötvös. The horizontal components were strongly perturbed peripheral to the prism mass anomaly, with the Gxx component adjacent to the prism displaying a signal of ~-40 Eötvös (SD of ±~10 Eötvös).The uncertainty and sensitivity analysis was then expanded to a reservoir scale regional geological model, and tested with data from flow simulations of the Otway Project CCS site. Results seen here again displayed a strong ability to detect various features within the reservoir - such as raw geology; net density change; and timelapse fluid migration. When modelling the regional geology prior to fluid injection, the downhole gravity gradiometry demonstrates the ability to delineate the relative geology of the region, and is particularly sensitive to subsurface layering. To explore the technique's capacity to monitor subsurface fluids, models of the time-variable net density change caused by the sequestration of CO2 were developed, and showed that downhole gravity gradiometry performed on a heterogeneous reservoir was capable of identifying the sequestered plume. Characterisation of the noise implicit in these reservoir models identified two independent sources, the geological noise - arising from the laterally complex and heterogeneous geology of the reservoir, and the noise associated with the time-variable fluid flow. Whilst the geological variations in density have characteristically large uncertainty distributions (input standard deviations of >±100 kg/m3), they are coherent throughout a reservoir injection, and time-series measurements of potential field components are only sensitive to variations and uncertainties in reservoir fluid density, which exhibit much lower standard deviations (~±25 kg/m3). In the latter cases, for Monte Carlo time-series models fluid injection, the output standard deviation for many components, notably Gz, Gzz, Gxx, was generally larger than the output uncertainties. Anomalies as high as ~50 Eötvös were observed for the Gzz component of the gradient tensor (SD ~±20 Eötvös), and as high as ~30 Eötvös for the Gxx component (SD ~±10 Eötvös), suggesting for the Otway geological system, downhole gravity gradiometry is capable of detecting the sequestered CO2 plume over the system noise associated with the injection. In addition, a model containing a simulated fluid leak above the reservoir was performed. Downhole gradiometry demonstrated the ability to discern a small leak with mass of ~16,000 tonnes (representing ~1/4 of the total injecta), with local signal as high as ~70 Eötvös for Gzz - above the detection threshold for current generation downhole gradiometers.Lastly, the reservoir modelling approach was expanded to remotely acquired satellite gravity data acquired from the GRACE (Gravity Recovery and Climate Experiment), and gravity gradiometry from GOCE (Gravity Field and Steady State Ocean Circulation Explorer) missions. The case studies modelled here were three CCS sites of varying scale (Sleipner, North Sea; In Salah, Algeria; and Otway, Australia) in addition to a large scale oil extraction site (Ghawar Oilfield, Saudi Arabia). All these reservoirs were experiencing mass change to injection (CCS) or petroleum extraction (Ghawar) over the time period the satellite missions were active. Geoid and gravity gradient data were extracted within the regional bounds of these reservoirs from satellite-derived global grids over monthly intervals, and these time-series were modelled using simple reservoir geometries. Over the period of time during which these data were acquired, the signals observed by the GRACE models displayed a strong ability to detect changes in geoid. Magnitudes of up to 1 mm were observed for the larger reservoirs, and ~0.25 mm for the smaller reservoirs, which are explainable by constrained fluid mass change within their subsurface. The gravity gradient approach was not able to conclusively replicate this success, largely due to the shorter time period during which GOCE was active and the resulting lack of data points. It was seen that the terrains overlying the reservoirs being monitored played an important role in the results; with those on land (Ghawar, In Salah, Otway) displaying signal above the level of noise (signal to noise ratio (SNR) of up to 0.49 for Ghawar) whereas the extensive noise for the marine case study (Sleipner) was larger than the reservoir signal (SNR of 0.09).The process of CCS injection involves significant mass change and density variations within the CCS reservoir. Such changes are amenable to monitoring with conventional - and unconventional - potential field techniques. Here I have demonstrated that downhole gravity gradiometry is capable of detecting subsurface fluid flow associated with CCS injection - and that the reservoir mass changes may induce observable potential field signal even satellite heights, which has important implications for global monitoring programs of the subsurface dynamics of reservoirs.Mode of access: World wide web1 online resource (xxii, 275, 12 pages) colour illustration
Fear of a brown planet: the 'Trump effect', right-wing populism, and Islamophobia in Australia
No full textTheoretical thesis.Bibliography: pages 63-82.Introduction: Literature review + methodology -- Chapter One: Leader of the Pack -- Chapter Two: Celebrity in Chief -- Conclusion: Weapons of Mass Destruction -- References.This thesis will argue how the explicit Islamophobic stance Donald Trump embodied during 2016-17, influenced a resurgence of right-wing populism in Australia. Amidst a global environment, characterised by notions of insecurity, Trump emerged victorious in his bid to win the 45th United States Presidency. His presidential claim to fame centered on a populist premise of 'Making America Great Again' through mobilising the disenfranchised white fringes of US society. The superpower's legitimisation of a nationalistic driven rhetoric presents a thriving area of interest within academia, specifically in localising the 'Trump effect' in the Australian context and examining its impact on Australian politicians and the media. The significance of my research project lies in the complexity of analysing the domestic media and political spheres, portraying a homogenous threatening perspective of the Othered identity, personified by Australian Muslims. However, this is not a novel concept. Previous research into Australia's settler-colonialist history reveals an embedded legacy premised upon systematically oppressing and demonising Indigenous and non-white bodies. In these deviations from the white majority, racialised manifestations of Islamophobia are justified: a public perception of the Muslim body as a sole aggressor in an otherwise peaceful world is reinforced through ethnocentric schemas advocated by those with political power. Regarding the 'Trump effect' that is characterised by an overwhelming Islamophobic sentiment prevailing throughout the West, the thesis will analyse key public addresses recorded during Trump's pre-presidential and post-inauguration campaigns. Through a Foucauldian discourse and visual cultural analysis, the effects of his Islamophobic representations of Islam and Muslims are compared with the rhetoric of the Australian political and media spheres. As such, iterations of the transnational nature of the 'Trump effect' are best exemplified through the controversial personalities of Pauline Hanson and Cory Bernardi. In concluding, my thesis evidences how Trump's position of power institutionalised a divisive rhetoric that normalised race hatred and hate speech in an unprecedented way. Therefore, the Australian populist response was legitimated in its overt adaptation of the 'Trump effect'.1 online resource ( 82 pages
Unpacking the value of supply chain integration and innovation ambidexterity in promoting business sustainability and brand image: implications for B2B manufacturing firms in a next-eleven emerging country
No full textThesis by publication.Includes bibliographical references.Chapter 1. Introduction -- Chapter 2. Improving manufacturers' business sustainability through innovation ambidexterity, CEOs' leadership style, and business unit managers' attitudes -- Chapter 3. Driving business to business brands : signal your sustainability and manage your customer relationships and attitudes -- Chapter 4. Does the ambidextrous integration of suppliers and customers contribute to radical and incremental innovation? -- Chapter 5. Discussion and conclusions -- Appendix.Increasing resource consumption and pollution, and their detrimental effects on the environment are forcing firms across the globe to adopt strategies directed at sustainability. This is especially so for business-to-business (B2B) manufacturing firms operating in emerging countries who intensively use natural resources in their operations and are blamed for observable impacts on the environment. Sustainability when viewed from a business perspective is defined as an organizational activity that is directed to reducing pollution and efficient use of energy and other resources aiming at diminishing the detrimental effects of firms' activities on the environment and human race. In an attempt to address the challenges that sustainability is raising, innovation is promoted as an especially important solution.In the pursuit of innovation, a widely acknowledged approach toward categorizing innovation is via the notions of radical and incremental innovation. While radical innovation involves substantial changes in technical skills, knowledge, and design, incremental innovation improves on a known product or the process for producing it, reinforcing existing engineering and manufacturing know-how. However, little emphasis has been given to unpacking the mechanisms by which radical and incremental innovation, when managed ambidextrously (hereafter referred to as innovation ambidexterity) drive sustainability. In addition, while marketing literature has focused on the necessity of transitioning toward sustainability, far less attention has been given to uncovering whether the investments necessary for B2B firms to adopt sustainability practices pay off in terms of improving their brands as a major marketing asset. Accordingly, this research examines the role of innovation ambidexterity in the sustainability of B2B manufacturing firms operating in emerging countries, as well as factors that support innovation and whether the pursuit of sustainability helps these firms in building strong brands and improving their long-term performance.This research adopts a thesis by publication format and comprises three inter-related but distinct papers. The first paper draws on organizational ambidexterity theory to investigate the relationship between innovation ambidexterity and sustainability in manufacturing firms operating in emerging countries. To unpack this relationship, this paper brings critical attention to the contingent role of CEOs' leadership style and business unit managers' attitudes toward sustainability. To test the theory, this paper uses a multi-informant dataset collected from production managers and supply chain managers in business units of manufacturing firms. The results show that innovation ambidexterity is a trigger for driving a firm's ability to pursue sustainability goals. Further, the results demonstrate that CEOs' leadership style and business unit managers' attitudes toward sustainability enhance the positive effect of innovation ambidexterity on sustainability. This paper advances the current literature on innovation and sustainability by delving into how firms can ambidextrously manage their radical and incremental innovation to support sustainability activities.The second paper brings signaling theory into the sustainability literature with a specific focus on emerging countries and explores the extent to which a firm's pursuit of sustainability underpins its ability to create a positive brand image, which in turn, promotes its market performance. In addition, this paper examines the roles of customer relationship management (CRM) and business customers' attitudes toward sustainability as keys to foster the relationship between sustainability practices and brand image. The dyadic data for this paper comes from cross-industry B2B firms and their customers. The findings reveal that sustainability practices significantly influence the generation of positive brand image perceived by customers and this relationship is significantly improved through use of CRM practices and customers' holding favorable attitudes toward sustainability. In doing so, this paper extends the boundaries of sustainability research and offers appropriate strategies for B2B firms to better direct their attention to sustainability practices in driving brand success and improve long-term performance.The third paper integrates the relational view and organizational ambidexterity theories and investigates how the individual and combined effects of supplier integration (SI) and customer integration (CI) help firms in emerging countries generate both radical and incremental innovation. In addition, this paper articulates the moderating role of internal integration in enhancing the relationship between external (supplier and customer) integration and radical and incremental innovation. Empirical support for the proposed effects comes from a triadic matched, multi-stakeholder (focal firms, suppliers and customers) design from broad range of industrial firms in the manufacturing sector. The findings indicate that SI and CI are not equally beneficial in driving both radical and incremental innovation. Moreover, the findings highlight the significant role of internal integration in improving the effects of external integration on radical and incremental innovation. The findings of this paper provide new insights for firms to manage available resources and capacities to integrate suppliers and customers into their operations to ensure they maximize innovation and performance.Overall, through the three papers, the thesis advances the literature by providing novel theoretical explanations to understand the determinants of innovation and sustainability across the supply chain, as well as the contribution that sustainability practices make to achieving superior brand image and organizational performance in emerging countries.Mode of access: World wide web1 online resource (v, 166 pages) graphs, table
The hydro‑geomorphic structure, function and evolution of chains‑of‑ponds: implications for recognition of these discontinuous watercourses in river management
No full textEmpirical thesis.Includes bibliographical referencesIntroduction -- The morphology and evolution of large chain‑of‑ponds river systems -- Surface water-subsurface water interactions in a large chain‑of‑ponds -- Diversity of chains-of-ponds and reach‑scale sensitivity analysis -- Discontinuous watercourses in river science and policy -- Discussion -- Appendices.The hydro‑geomorphic structure and function of river and wetland systems provide a physical template for ecosystem functions, allowing for their recognition, conservation and rehabilitation. This thesis examines the diverse geomorphic structure and hydrological processes of a spectrum of chain‑of‑ponds morphologies, identifying the intrinsic and extrinsic controls on their formation, evolution and impairment or loss. Chains‑of‑ponds consist of steep‑sided ponds separated by densely vegetated alluvial valley‑fill sediments that contain shallow ephemeral channels or preferential flow paths. They are part of the spectrum of discontinuous watercourses that are important landscape features due to their unique geomorphological, hydrological and ecological function.Analysis of seven headwater chain‑of‑ponds reaches reveal morphological diversity, in both planform and stratigraphy, and in varying stages of evolution. Sensitivity assessments of these reaches, combined with two‑dimensional hydraulic modelling, precipitated the quantification of measurable pond and planform characteristics associated with geomorphic condition. This examination developed three quantitative metrics that provide a measure of event sensitivity, morphological sensitivity and change sensitivity that can be used to guide the management of smaller‑scale headwater systems.Stratigraphic analysis and luminescence dating of larger‑scale chains‑of‑ponds on higher‑order streams show different formation processes that result from threshold changes in fluvial energy over the late Quaternary, with antecedent controls on the size and position of much deeper (up to 7 m) and more stable ponds. This adds important insight to the range of non‑linear responses through both intrinsic controls and also more complex responses from the persistence of palaeo landforms.This analyses improve the understanding of intrinsic controls on fluvial evolution and will help assess recovery potential through forecasting future trajectories, guiding approaches to maintaining or restoring ecosystem function of discontinuous headwater systems in southeast Australia and similar systems internationally.Stable isotopes (δ18O and δ2H), 222Rn, and pond and floodplain water levels revealed that the hydrology and ecosystem function of large‑scale chains‑of‑ponds, and discontinuous fluvial systems more generally, could be highly sensitive to local‑scale water extraction, shallow groundwater aquifer interference and changes to groundwater recharge due to climatic changes. The surficial appearance of discontinuity masks the continuous longitudinal flow of the alluvial aquifer during both high‑flow and no‑flow stages, highlighting the importance of subsurface and hyporheic processes in defining the hydrological character of a river.This thesis strengthens the understanding of the hydro‑geomorphological processes of discontinuous systems to facilitate ecosystem managers to develop workable strategies for protecting and managing systems that, due to their discontinuous form, do not as yet receive the same legal status or protection as other rivers.Mode of access: World wide web1 online resource (xii, 221 pages) colour illustrations, colour map
Ecologies of language learning and teaching: a teacher cognition of language learning environments beyond the classroom
No full textEmpirical thesis.Bibliography: pages 346-369.Chapter One. Introduction -- Chapter Two. Literature review -- Chapter Three. Methodology and research design -- Chapter Four. Teachers' initial conceptions and beliefs -- Chapter Five. Teacher responses and attitudes to student data -- Chapter Six. Narrative case studies on teacher learning processes -- Chapter Seven. Discussion -- Chapter Eight. Conclusion -- References -- Appendices.How language teachers conceptualise their students' language learning environments, the teacher's roles within these environments, and the relationship between in-class and out-of-class learning in particular may significantly influence what teachers do in the classroom.This research explores language teacher cognition of language learning and teaching beyond the classroom and provides insights into teacher learning processes as a consequence of an inquiry into students' language learning practices and environments. Teacher attitudes towards the inquiry process, the development of teacher beliefs about their students' learning environments, their subsequent actions in teaching, and their reconceptualisation of their roles are examined. This is achieved through a multiple case study design involving narrative and thematic analysis of multiple qualitative data sources using visual data, semi-structured face-to-face interviews, and reflective journals entries by the researcher.Teacher participants drew mind maps to represent their conceptualisation of a good language learning environment. Semi-structured interviews were also conducted with the teachers prior to and following their engagement with student survey responses and a mind map drawn by their students each pertaining to their language learning practices. In that way, teachers were encouraged to adopt a holistic view of international students' language learning practices and their language learning environments beyond the classroom from ecological perspectives. This research method also promoted a deeper understanding of student learning ecologies.Four key findings emerged from this research investigation. First, teachers varied in their conceptualisations of ideal student language learning practices and the necessary elements of a good language learning environment beyond the classroom. Second, the teacher inquiry with an ecological perspective prompted teachers to better understand students' language learning practices beyond the classroom using emerging issues from student data. Third, teachers' ecological views increased their awareness of the relationship between student out-of-class language learning and teaching through extensive reflective practice in the course of the inquiry. It also further guided teachers to develop their beliefs and teaching ideas on how to link in-class and out-of-class language learning experiences, and then to reconceptualise their role in student learning. As such, this study demonstrated that teacher learning occurred throughout the inquiry process while working collaboratively with the researcher. Fourth, the openness of the teacher towards learning from new information, the degree of teacher agency in practice, and the teacher's emotions appeared to shape differences in the development of beliefs and teaching actions as outcomes of teacher learning.Overall, this study suggests that teacher reflection on daily practices is effective for promoting their ecological perspectives of student language learning. Moreover, it is also effective in teacher inquiries into student learning to prompt reconsideration of student learning needs and their role in supporting student learning beyond the classroom.Based on its findings, this study contributes to an academic understanding of ecologies of language learning and teaching, particularly the role of teacher ecological practices. This is supported by an inquiry into student learning in relation to student learning ecologies. In addition, the empirical evidence showing the development of teacher cognition towards the reconceptualisation of the teacher's role in their situated contexts demonstrates the effective use of an ecological framework in teacher cognition research.Mode of access: World wide web1 online resource (xvii, 431 pages) diagrams, table
Trust management in crowdsourcing environments
No full textEmpirical thesis.Bibliography: pages 146-165.1. Introduction -- 2. Literature review -- 3. Trustworthy worker selection based on context-aware trust evaluation -- 4. Spam worker defense based on trust vector -- 5. Spam worker identification based on trust matrix -- 6. Trust-aware worker recommendation -- 7. Conclusion -- Appendices.As a cost-effective model for solving problems, crowdsourcing has been widely applied in various human intelligence tasks, such as data labeling, data translation, and prediction. However, without adequate trust management, a large number of untrustworthy workers submit low-quality or even junk answers in the tasks to benefit themselves or sabotage their competitors' crowdsourcing processes. The disturbance or attacks not only significantly increase the cost of solving a task, but also drastically reduce the effectiveness of crowdsourcing processes. Therefore, selecting trustworthy workers to participate in tasks has become a top-priority demand in crowdsourcing environments. To achieve an effective trustworthy worker selection, three challenging sub-problems including context-aware trust evaluation, spam worker defense, and trustworthy worker recommendation have to be tackled. As such, in this thesis, we systematically propose our solutions for the three sub-challenges. The main contributions are summarized as follows.In a crowdsourcing platform, a worker's trustworthiness varies in different contexts, complicating the trust evaluation of a crowdsourcing worker. Thus, we propose a new context-aware trust model that evaluates a worker's trust in two primary crowdsourcing contexts, i.e., the context of task type and the context of reward amount, respectively. In particular, we first propose a task type taxonomy and a task reward amount taxonomy. Based on them, we devise two novel context-aware trust metrics: Task Type-aware Trust (TaTrust) and Reward Amount-aware Trust (RaTrust). Finally, we devise a multi-objective combinatorial optimization algorithm to effectively select trustworthy workers.To defend against the threats from the spam workers who masquerade themselves as "trustworthy" workers with "good" reputations by colluding with their accomplices, we propose a new spam worker defense model based on our proposed Worker Trust Vector (WTV). A WTV consisting of the trust opinions from different requesters can indicate a worker's global trust level. Based on the workers' WTVs, we then propose an algorithm to effectively defend against spam workers.Moreover, to effectively and proactively identify spam workers, we propose a novel spam worker identification model. In this model, we first devise a novel worker trust representation called Worker Trust Matrix (WTM). A worker's WTM is essentially a global trust feature set where each element is a local trust indicator called trust trace. A trust trace measures the extent to which a requester trusts a worker in a trust subnetwork centering on the requester. Taking the WTMs as input, we then devise a learning-based algorithm to predict each worker's identity. With our proposed WTM-based model, spam workers are precisely identified and then prohibited from participating in the tasks.Furthermore, we propose a novel trust-aware model to recommend trustworthy workers to participate in tasks. In this model, we tackle the homogeneous worker, dishonest behaviours, data sparsity, and cold start problems in generating worker recommendations. In particular, we first propose two similarity metrics to measure two requesters' similarities in transacting with the workers they commonly trust and the workers they commonly distrust, respectively. Targeting the data sparsity problem, we propose a new trust sub-network extraction algorithm (TSE) to effectively discover requesters who can provide trustworthy recommendation suggestions. Finally, we suggest two strategies for solving the cold start problem.All the models proposed in this thesis have been validated and evaluated through extensive experiments on real datasets or real scenarios. The results have demonstrated that the proposed models significantly outperform the comparable models in the existing studies in terms of effectively selecting trustworthy workers.Mode of access: World wide web1 online resource (xvi, 165 pages) graphs, table
Toward theory advancement in mathematical cognition and teacher cognition
No full textThesis by publication.Bibliography: pages 95-99.1. Introduction -- 2. Advancing theory building in mathematics education -- 3. Transcending dualisms in mathematical cognition : toward a dialogical framing -- 4. Challenging conceptualisations of teacher knowledge : toward emerging theoretical perspectives -- 5. Going beyond intuitive models of teacher noticing : toward emerging theoretical perspectives -- 6. Conclusion -- References -- Appendices.This thesis is concerned with mathematical cognition and teacher cognition, two of the subfields within mathematics education research. Within each there is a broad range of diverse theories that cultivate varied understandings of complex phenomena in mathematical thinking, learning, and teaching. However, the abundance and diversity of theories can polarize perspectives and foster the development of narrow and restricting theoretical accounts. This thesis uses existing theoretical tensions to stimulate the development of more powerful theoretical accounts by coordinating theoretical perspectives in mathematical cognition and teacher cognition.The thesis consists of three articles, which aim to blend opposing theoretical perspectives to reveal complementarity in the field of mathematical knowing and learning, challenge assumptions to reveal restrictions in the field of teacher knowledge, and portray some complex phenomena that cannot be accounted for using intuitive models of teacher noticing. These articles link apparently disparate approaches, revealing the complexity of the phenomena under consideration and the limitations of existing theoretical accounts for them.The first article blends theoretical perspectives from two local theories of mathematical cognition (abstraction-from-actions and abstraction-from-objects) to present a bi-directional, dynamic, non-linear view of mathematical concept formation. The second article examines teacher cognition, discussing existing conceptualizations of mathematics teacher knowledge, revealing their limitations, and offering alternative views that direct attention to underexplored issues. The third article examines teacher cognition from the perspective of the construct of teacher noticing, drawing on insights from cognitive science and the applied science of human factors to develop a model of teacher noticing which challenges intuitive assumptions and views individual and environment as interdependent and inseparable.It is hoped that these contributions add value to the field by advancing knowledge, providing links between previous conceptualizations, and offering fresh insights and theoretical views.Mode of access: World wide web1 online resource (vi, 110 pages) diagram
Interrogating corporate social responsibility through the lens of environmental justice: the case of corporate waste
No full textTheoretical thesis.Bibliography: pages 62-67.1. Introduction -- 2. Literature review -- 3. Methodology. -- 4. Findings - incorporation of environmental justice -- 5. Findings - Challenges and opportunities -- 6. Discussion - Role of CSR? -- 7. Conclusion.Existing literature on Corporate Social Responsibility (CSR) highlights the importance of integrating social, environmental and economic factors into corporate operations. Consideration for environmental justice however remains limited, and concerns remain regarding if and how corporations are considering issues of distributional, procedural and recognition justice in their actions. Through a case study of corporate waste in Sydney, Australia, this thesis aims to explore if and how corporate actors are addressing environmental justice in their CSR strategies. Based on a review of CSR reports and interviews with corporate actors, the thesis provides insights into the opportunities and challenges of corporate adoption of environmental justice into CSR frameworks. The findings demonstrate d that despite the barriers experienced with the structural versatility, influences from conflicting interests, and the invisibility of environmental justice incorporation, CSR was found to be a supportive facilitator for incorporating environmental justice into the practices of corporations. It is recommended that corporations increase communication regarding their integration of environmental justice into their CSR practices in order to allow greater transparency and to p rovide opportunities for further CSR consideration of environmental justice.1 online resource (69 pages