Image synthesis based on a model of human vision

Modern computer graphics systems are able to construct renderings of such high quality that viewers are deceived into regarding the images as coming from a photographic source. Large amounts of computing resources are expended in this rendering process, using complex mathematical models of lighting and shading. However, psychophysical experiments have revealed that viewers only regard certain informative regions within a presented image. Furthermore, it has been shown that these visually important regions contain low-level visual feature differences that attract the attention of the viewer. This thesis will present a new approach to image synthesis that exploits these experimental findings by modulating the spatial quality of image regions by their visual importance. Efficiency gains are therefore reaped, without sacrificing much of the perceived quality of the image. Two tasks must be undertaken to achieve this goal. Firstly, the design of an appropriate region-based model of visual importance, and secondly, the modification of progressive rendering techniques to effect an importance-based rendering approach. A rule-based fuzzy logic model is presented that computes, using spatial feature differences, the relative visual importance of regions in an image. This model improves upon previous work by incorporating threshold effects induced by global feature difference distributions and by using texture concentration measures. A modified approach to progressive ray-tracing is also presented. This new approach uses the visual importance model to guide the progressive refinement of an image. In addition, this concept of visual importance has been incorporated into supersampling, texture mapping and computer animation techniques. Experimental results are presented, illustrating the efficiency gains reaped from using this method of progressive rendering. This visual importance-based rendering approach is expected to have applications in the entertainment industry, where image fidelity may be sacrificed for efficiency purposes, as long as the overall visual impression of the scene is maintained. Different aspects of the approach should find many other applications in image compression, image retrieval, progressive data transmission and active robotic vision.

The planning of airport regions and National Aviation Policy Issues and challenges in the Australian experience 2008-2009

The planning of airports has long been contentious because of their localisation of negative impacts. The globalisation, commercialisation and deregulation of the aviation industry has unleashed powerful new economic forces both on and offairport. Over the last two decades, many airports have evolved into airport cities located at the heart of the wider aerotropolis region. This shifts the appropriate scale of planning analysis towards broader regional concerns. However,governments have been slow to respond and airport planning usually remains poorly integrated with local, city and regional planning imperatives. The Australian experience exemplifies the divide. The privatization of major Australian airports from 1996 has seen billions of dollars spent on new airside and landside infrastructure but with little oversight from local and state authorities because the ultimate authority for on-airport development is the Federal Minister for Transport. Consequently, there have been growing tensions in many major airport regions between the private airport lessee and the broader community, exacerbated by both the building of highly conspicuous non-aeronautical developments and growing airport area congestion. This paper examines the urban planning content of Australia’s national aviation policy review (2008-09) with reference to current and potential opportunities for all-of-region collaboration in the planning process.

Fusing shrinking and expanding active contour models for robust IRIS segmentation

The performance of iris recognition systems is significantly affected by the segmentation accuracy, especially in non- ideal iris images. This paper proposes an improved method to localise non-circular iris images quickly and accurately. Shrinking and expanding active contour methods are consolidated when localising inner and outer iris boundaries. First, the pupil region is roughly estimated based on histogram thresholding and morphological operations. There- after, a shrinking active contour model is used to precisely locate the inner iris boundary. Finally, the estimated inner iris boundary is used as an initial contour for an expanding active contour scheme to find the outer iris boundary. The proposed scheme is robust in finding exact the iris boundaries of non-circular and off-angle irises. In addition, occlusions of the iris images from eyelids and eyelashes are automatically excluded from the detected iris region. Experimental results on CASIA v3.0 iris databases indicate the accuracy of proposed technique.

Queensland Aborigines, multiple realities and the social sources of suffering: Psychiatry and moral regions of being (Part 1)

This two part paper considers the experience of a range of magico-religious experiences (such as visions and voices) and spirit beliefs in a rural Aboriginal town. The papers challenge the tendency of institutionalised psychiatry to medicalise the experiences and critiques the way in which its individualistic practice is intensified in the face of an incomprehensible Aboriginal „other‟ to become part of the power imbalance that characterises the relationship between Indigenous and white domains. The work reveals the internal differentiation and politics of the Aboriginal domain, as the meanings of these experiences and actions are contested and negotiated by the residents and in so doing they decentre the concerns of the white domain and attempt to control their relationship with it. Thus the plausibility structure that sustains these multiple realities reflects both accommodation and resistance to the material and historical conditions imposed and enacted by mainstream society on the residents, and to current socio- political realities. I conclude that the residents‟ narratives chart the grounds of moral adjudication as the experiences were rarely conceptualised by local people as signs of individual pathology but as reflections of social reality. Psychiatric drug therapy and the behaviourist assumptions underlying its practice posit atomised individuals as the appropriate site of intervention as against the multiple realities revealed by the phenomenology of the experiences. The papers thus call into question Australian mainstream „commonsense‟ that circulates about Aboriginal and Torres Strait Islander people which justifies representations of them as sickly outcasts in Australian society.

Practising public relations in the global community of the 21st century : a comparison of business practices and culture in three world regions

Non-Western practitioners across the globe instinctively attempt to implement Western-based public relations models and theories, often unsuccessfully, regardless of their surrounding environment. This paper reviews business practices and reveals that in Europe, company interests are a main priority, while in Asia, the line between business and personal relationships is extremely blurred. Cultural dimensions and topois were even more varied between the three regions. Implications for the adoption of Western models of public relations practice are discussed.

Active flow control bump design using hybrid Nash-game coupled to evolutionary algorithms

In this paper, the optimal design of an active flow control device; Shock Control Bump (SCB) on suction and pressure sides of transonic aerofoil to reduce transonic total drag is investigated. Two optimisation test cases are conducted using different advanced Evolutionary Algorithms (EAs); the first optimiser is the Hierarchical Asynchronous Parallel Evolutionary Algorithm (HAPMOEA) based on canonical Evolutionary Strategies (ES). The second optimiser is the HAPMOEA is hybridised with one of well-known Game Strategies; Nash-Game. Numerical results show that SCB significantly reduces the drag by 30% when compared to the baseline design. In addition, the use of a Nash-Game strategy as a pre-conditioner of global control saves computational cost up to 90% when compared to the first optimiser HAPMOEA.

Predicting active material utilisation in LiFePO4 electrodes using a multi-scale mathematical model

A mathematical model is developed to simulate the discharge of a LiFePO4 cathode. This model contains 3 size scales, which match with experimental observations present in the literature on the multi-scale nature of LiFePO4 material. A shrinking-core is used on the smallest scale to represent the phase-transition of LiFePO4 during discharge. The model is then validated against existing experimental data and this validated model is then used to investigate parameters that influence active material utilisation. Specifically the size and composition of agglomerates of LiFePO4 crystals is discussed, and we investigate and quantify the relative effects that the ionic and electronic conductivities within the oxide have on oxide utilisation. We find that agglomerates of crystals can be tolerated under low discharge rates. The role of the electrolyte in limiting (cathodic) discharge is also discussed, and we show that electrolyte transport does limit performance at high discharge rates, confirming the conclusions of recent literature.