Robot navigation in sensor space

This thesis investigates the problem of robot navigation using only landmark bearings. The proposed system allows a robot to move to a ground target location specified by the sensor values observed at this ground target posi- tion. The control actions are computed based on the difference between the current landmark bearings and the target landmark bearings. No Cartesian coordinates with respect to the ground are computed by the control system. The robot navigates using solely information from the bearing sensor space. Most existing robot navigation systems require a ground frame (2D Cartesian coordinate system) in order to navigate from a ground point A to a ground point B. The commonly used sensors such as laser range scanner, sonar, infrared, and vision do not directly provide the 2D ground coordi- nates of the robot. The existing systems use the sensor measurements to localise the robot with respect to a map, a set of 2D coordinates of the objects of interest. It is more natural to navigate between the points in the sensor space corresponding to A and B without requiring the Cartesian map and the localisation process. Research on animals has revealed how insects are able to exploit very limited computational and memory resources to successfully navigate to a desired destination without computing Cartesian positions. For example, a honeybee balances the left and right optical flows to navigate in a nar- row corridor. Unlike many other ants, Cataglyphis bicolor does not secrete pheromone trails in order to find its way home but instead uses the sun as a compass to keep track of its home direction vector. The home vector can be inaccurate, so the ant also uses landmark recognition. More precisely, it takes snapshots and compass headings of some landmarks. To return home, the ant tries to line up the landmarks exactly as they were before it started wandering. This thesis introduces a navigation method based on reflex actions in sensor space. The sensor vector is made of the bearings of some landmarks, and the reflex action is a gradient descent with respect to the distance in sensor space between the current sensor vector and the target sensor vec- tor. Our theoretical analysis shows that except for some fully characterized pathological cases, any point is reachable from any other point by reflex action in the bearing sensor space provided the environment contains three landmarks and is free of obstacles. The trajectories of a robot using reflex navigation, like other image- based visual control strategies, do not correspond necessarily to the shortest paths on the ground, because the sensor error is minimized, not the moving distance on the ground. However, we show that the use of a sequence of waypoints in sensor space can address this problem. In order to identify relevant waypoints, we train a Self Organising Map (SOM) from a set of observations uniformly distributed with respect to the ground. This SOM provides a sense of location to the robot, and allows a form of path planning in sensor space. The navigation proposed system is analysed theoretically, and evaluated both in simulation and with experiments on a real robot.

“I want to see the Queen” : experiences of service use by ageing people with an intellectual disability

People with intellectual disability are a relatively new but growing minority group within Australia's ageing population. Disability policies point to the equal right of people with disabilities to a quality of life similar to that of other citizens. Disability services are increasingly required to provide individualised and responsive services, irrespective of age, for people with lifelong disabilities. The present study explored the everyday lives of older people with intellectual disability in Victoria and Queensland, examining their experiences of using disability services and the ways in which services responded to their ageing. The aim of the study was to inform practice and service development for older people with intellectual disability. The findings suggest that services facilitate important social relationships with other service users and staff. Most older people had a sense of belonging and led busy but directionless lives in two disconnected worlds. Their lives were subject to significant external present-focused control. Yet, despite this, neither services nor family members took responsibility for ensuring their sense of continuity or supporting the development of plans about their future. The experiences described suggest an urgent need for, but significant challenges in the implementation of, holistic indivdualised planning similar to the UK concept of person-centred planning.

Hypercapitalism : an investigation into the relationship between language, new media, and social perceptions of value

Overall, this thesis purports to make two significant contributions to knowledge. The first is a foundational critique of political economy in the context of an emergent global knowledge economy. The second is a method for analysing evaluations in language. The relationships that give coherence to those two contributions are as follows. The widely-heralded emergence of a knowledge economy indicates that more intimate aspects of human activity have become exposed to commodification on a massive scale, specifically, activities associated with thought and language. Correspondingly, more abstract forms of value have developed as the products of thought and language have become dominant commodity forms. Historical investigation shows that value has moved from an objective category in political economy, pertaining to such substances as precious metals and land, to become situated today predominantly in “expert” expressions of language, or more precisely, their institutional contexts of production. These are now propagated and circulated on a global scale. Legal, political, and technological developments are key in the development of new, more abstract forms of labour and value, although the relationships connecting these are neither simple nor direct. They are, however, inseparably related in the trajectories that this thesis describes. Consequently they are dealt with inseparably throughout.

New Approach on Robust Delay-Dependent H∞ Control for Uncertain T-S Fuzzy Systems With Interval Time-Varying Delay

This paper investigates the robust H∞ control for Takagi-Sugeno (T-S) fuzzy systems with interval time-varying delay. By employing a new and tighter integral inequality and constructing an appropriate type of Lyapunov functional, delay-dependent stability criteria are derived for the control problem. Because neither any model transformation nor free weighting matrices are employed in our theoretical derivation, the developed stability criteria significantly improve and simplify the existing stability conditions. Also, the maximum allowable upper delay bound and controller feedback gains can be obtained simultaneously from the developed approach by solving a constrained convex optimization problem. Numerical examples are given to demonstrate the effectiveness of the proposed methods.

A study into the permeability and compressibility of Australian bagasse pulp

This is an experimental study into the permeability and compressibility properties of bagasse pulp pads. Three experimental rigs were custom-built for this project. The experimental work is complemented by modelling work. Both the steady-state and dynamic behaviour of pulp pads are evaluated in the experimental and modelling components of this project. Bagasse, the fibrous residue that remains after sugar is extracted from sugarcane, is normally burnt in Australia to generate steam and electricity for the sugar factory. A study into bagasse pulp was motivated by the possibility of making highly value-added pulp products from bagasse for the financial benefit of sugarcane millers and growers. The bagasse pulp and paper industry is a multibillion dollar industry (1). Bagasse pulp could replace eucalypt pulp which is more widely used in the local production of paper products. An opportunity exists for replacing the large quantity of mainly generic paper products imported to Australia. This includes 949,000 tonnes of generic photocopier papers (2). The use of bagasse pulp for paper manufacture is the main application area of interest for this study. Bagasse contains a large quantity of short parenchyma cells called ‘pith’. Around 30% of the shortest fibres are removed from bagasse prior to pulping. Despite the ‘depithing’ operations in conventional bagasse pulp mills, a large amount of pith remains in the pulp. Amongst Australian paper producers there is a perception that the high quantity of short fibres in bagasse pulp leads to poor filtration behaviour at the wet-end of a paper machine. Bagasse pulp’s poor filtration behaviour reduces paper production rates and consequently revenue when compared to paper production using locally made eucalypt pulp. Pulp filtration can be characterised by two interacting factors; permeability and compressibility. Surprisingly, there has previously been very little rigorous investigation into neither bagasse pulp permeability nor compressibility. Only freeness testing of bagasse pulp has been published in the open literature. As a result, this study has focussed on a detailed investigation of the filtration properties of bagasse pulp pads. As part of this investigation, this study investigated three options for improving the permeability and compressibility properties of Australian bagasse pulp pads. Two options for further pre-treating depithed bagasse prior to pulping were considered. Firstly, bagasse was fractionated based on size. Two bagasse fractions were produced, ‘coarse’ and ‘medium’ bagasse fractions. Secondly, bagasse was collected after being processed on two types of juice extraction technology, i.e. from a sugar mill and from a sugar diffuser. Finally one method of post-treating the bagasse pulp was investigated. The effects of chemical additives, which are known to improve freeness, were also assessed for their effect on pulp pad permeability and compressibility. Pre-treated Australian bagasse pulp samples were compared with several benchmark pulp samples. A sample of commonly used kraft Eucalyptus globulus pulp was obtained. A sample of depithed Argentinean bagasse, which is used for commercial paper production, was also obtained. A sample of Australian bagasse which was depithed as per typical factory operations was also produced for benchmarking purposes. The steady-state pulp pad permeability and compressibility parameters were determined experimentally using two purpose-built experimental rigs. In reality, steady-state conditions do not exist on a paper machine. The permeability changes as the sheet compresses over time. Hence, a dynamic model was developed which uses the experimentally determined steady-state permeability and compressibility parameters as inputs. The filtration model was developed with a view to designing pulp processing equipment that is suitable specifically for bagasse pulp. The predicted results of the dynamic model were compared to experimental data. The effectiveness of a polymeric and microparticle chemical additives for improving the retention of short fibres and increasing the drainage rate of a bagasse pulp slurry was determined in a third purpose-built rig; a modified Dynamic Drainage Jar (DDJ). These chemical additives were then used in the making of a pulp pad, and their effect on the steady-state and dynamic permeability and compressibility of bagasse pulp pads was determined. The most important finding from this investigation was that Australian bagasse pulp was produced with higher permeability than eucalypt pulp, despite a higher overall content of short fibres. It is thought this research outcome could enable Australian paper producers to switch from eucalypt pulp to bagasse pulp without sacrificing paper machine productivity. It is thought that two factors contributed to the high permeability of the bagasse pulp pad. Firstly, thicker cell walls of the bagasse pulp fibres resulted in high fibre stiffness. Secondly, the bagasse pulp had a large proportion of fibres longer than 1.3 mm. These attributes helped to reinforce the pulp pad matrix. The steady-state permeability and compressibility parameters for the eucalypt pulp were consistent with those found by previous workers. It was also found that Australian pulp derived from the ‘coarse’ bagasse fraction had higher steady-state permeability than the ‘medium’ fraction. However, there was no difference between bagasse pulp originating from a diffuser or a mill. The bagasse pre-treatment options investigated in this study were not found to affect the steady-state compressibility parameters of a pulp pad. The dynamic filtration model was found to give predictions that were in good agreement with experimental data for pads made from samples of pretreated bagasse pulp, provided at least some pith was removed prior to pulping. Applying vacuum to a pulp slurry in the modified DDJ dramatically reduced the drainage time. At any level of vacuum, bagasse pulp benefitted from chemical additives as quantified by reduced drainage time and increased retention of short fibres. Using the modified DDJ, it was observed that under specific conditions, a benchmark depithed bagasse pulp drained more rapidly than the ‘coarse’ bagasse pulp. In steady-state permeability and compressibility experiments, the addition of chemical additives improved the pad permeability and compressibility of a benchmark bagasse pulp with a high quantity of short fibres. Importantly, this effect was not observed for the ‘coarse’ bagasse pulp. However, dynamic filtration experiments showed that there was also a small observable improvement in filtration for the ‘medium’ bagasse pulp. The mechanism of bagasse pulp pad consolidation appears to be by fibre realignment. Chemical additives assist to lubricate the consolidation process. This study was complemented by pulp physical and chemical property testing and a microscopy study. In addition to its high pulp pad permeability, ‘coarse’ bagasse pulp often (but not always) had superior physical properties than a benchmark depithed bagasse pulp.

Vitronectin modulates human mesenchymal stem cell response to insulin-like growth factor-I and transforming growth factor beta 1 in a serum-free environment

The use of animal sera for the culture of therapeutically important cells impedes the clinical use of the cells. We sought to characterize the functional response of human mesenchymal stem cells (hMSCs) to specific proteins known to exist in bone tissue with a view to eliminating the requirement of animal sera. Insulin-like growth factor-I (IGF-I), via IGF binding protein-3 or -5 (IGFBP-3 or -5) and transforming growth factor-beta 1 (TGF-beta(1)) are known to associate with the extracellular matrix (ECM) protein vitronectin (VN) and elicit functional responses in a range of cell types in vitro. We found that specific combinations of VN, IGFBP-3 or -5, and IGF-I or TGF-beta(1) could stimulate initial functional responses in hMSCs and that IGF-I or TGF-beta(1) induced hMSC aggregation, but VN concentration modulated this effect. We speculated that the aggregation effect may be due to endogenous protease activity, although we found that neither IGF-I nor TGF-beta(1) affected the functional expression of matrix metalloprotease-2 or -9, two common proteases expressed by hMSCs. In summary, combinations of the ECM and growth factors described herein may form the basis of defined cell culture media supplements, although the effect of endogenous protease expression on the function of such proteins requires investigation.

An adaptable framework for the teaching and assessment of software development across year levels

Few frameworks exist for the teaching and assessment of programming subjects that are coherent and logical. Nor are they sufficiently generic and adaptable to be used outside the particular tertiary institutions in which they were developed. This paper presents the Teaching and Assessment of Software Development (TASD) frame-work. We describe its development and implementation at an Australian university and demonstrate, with examples, how it has been used, with supporting data. Extracts of criteria sheets (grading rubrics) for a variety of assessment tasks are included. The numerous advantages of this new framework are discussed with comparisons made to those reported in the published literature.

Identifying the learning development of students who are refugees

Students who are refugees need understanding and support to settle successfully into mainstream Australian classrooms. Teachers not aware of students’ prior learning and the process of second language acquisition may have difficulty providing the most appropriate learning environments to meet these students’ needs. This study found that, with no coordination of information on students’ learning backgrounds nor of their learning needs and development, students were in danger of being identified as at-risk of having a learning disability, with little support to substantiate such claims.

Small business pedagogic practices

Understanding how learning for small businesses should best proceed constitutes a worthwhile, yet challenging, pedagogic project. In order to maintain their viability, small businesses need to be able to respond to new practices and tasks. Yet small businesses seem neither attracted to nor to value the kinds of taught courses that are the standard pedagogic practice of vocational education systems.

The speed paradox : the misalignment between driver attitudes and speeding behaviour

This paper reports on a study investigating preferred driving speeds and frequency of speeding of 320 Queensland drivers. Despite growing community concern about speeding and extensive research linking it to road trauma, speeding remains a pervasive, and arguably, socially acceptable behaviour. This presents an apparent paradox regarding the mismatch between beliefs and behaviours, and highlights the necessity to better understand the factors contributing to speeding. Utilising self-reported behaviour and attitudinal measures, results of this study support the notion of a speed paradox. Two thirds of participants agreed that exceeding the limit is not worth the risks nor is it okay to exceed the posted limit. Despite this, more than half (58.4%) of the participants reported a preference to exceed the 100km/hour speed limit, with one third preferring to do so by 10 to 20 km/hour. Further, mean preferred driving speeds on both urban and open roads suggest a perceived enforcement tolerance of 10%, suggesting that posted limits have limited direct influence on speed choice. Factors that significantly predicted the frequency of speeding included: exposure to role models who speed; favourable attitudes to speeding; experiences of punishment avoidance; and the perceived certainty of punishment for speeding. These findings have important policy implications, particularly relating to the use of enforcement tolerances.

The effect of monocular and binocular cataract blur on postural stability among older adults

Purpose: First-eye cataract surgery can reduce the rate of falls among older adults, yet the effect of second-eye surgery on the rate of falling remains unclear. The present study investigated the effect of monocular and binocular simulated cataract blur on postural stability among older adults. Methods: Postural stability was assessed on 34 healthy older adults (mean 68.2 years, SD 3.5) with normal vision, using a portable force platform (BT4, HUR Labs, Finland) which collected data on centre of pressure (COP) displacement. Stability was assessed on firm and foam surfaces under four binocular viewing conditions using Vistech filters to simulate cataract blur: [1] best-corrected vision both eyes; [2] blur over non-dominant eye, [3] blur over dominant eye and [4] blur over both eyes. Binocular logMAR visual acuity, Pelli-Robson contrast sensitivity and stereoacuity were also measured under these viewing conditions and ocular dominance measured using the hole-in-card test. Generalized estimating equations with an exchangeable correlation structure examined the effect of the surface and vision conditions on postural stability. Results: Visual acuity and contrast sensitivity were significantly reduced under monocular and binocular cataract blur compared to normal viewing. All blur conditions resulted in loss of stereoacuity. Binocular cataract blur significantly reduced postural stability compared to normal vision on the firm (COP path length; p=0.013) and foam surface (anterior-posterior COP RMS, COP path length and COP area; p<0.01). However, no significant differences in postural stability were found between the monocular blur conditions compared to normal vision, or between the dominant and non-dominant monocular blur conditions on either the firm or foam surfaces. Conclusions: Findings indicate that binocular blur significantly impairs postural stability, and suggests that improvements in postural stability may justify first-eye cataract surgery, particularly during somatosensory disruption. Postural stability was not significantly impaired in the monocular cataract blur conditions compared to the normal vision condition, nor was there any effect of ocular dominance on postural stability in the presence of monocular cataract blur.

A summary view of government cost recovery policies in Australia and New Zealand relating to the supply of public sector information

Researching administrative history is problematical. A trail of authoritative documents is often hard to find; and useful summaries can be difficult to organise, especially if source material is in paper formats in geographically dispersed locations. In the absence of documents, the reasons for particular decisions and the rationale underpinning particular policies can be confounded as key personnel advance in their professions and retire. The rationale for past decisions may be lost for practical purposes; and if an organisation’s memory of events is diminished, its learning through experience is also diminished. Publishing this document tries to avoid unnecessary duplication of effort by other researchers that need to venture into how policies of charging for public sector information have been justified. The author compiled this work within a somewhat limited time period and the work does not pretend to be a complete or comprehensive analysis of the issues.----- A significant part of the role of government is to provide a framework of legally-enforceable rights and obligations that can support individuals and non-government organisations in their lawful activities. Accordingly, claims that governments should be more ‘business-like’ need careful scrutiny. A significant supply of goods and services occurs as non-market activity where neither benefits nor costs are quantified within conventional accounting systems or in terms of money. Where a government decides to provide information as a service; and information from land registries is archetypical, the transactions occur as a political decision made under a direct or a clearly delegated authority of a parliament with the requisite constitutional powers. This is not a market transaction and the language of the market confuses attempts to describe a number of aspects of how governments allocate resources.----- Cost recovery can be construed as an aspect of taxation that is a sole prerogative of a parliament. The issues are fundamental to political constitutions; but they become more complicated where states cede some taxing powers to a central government as part of a federal system. Nor should the absence of markets be construed necessarily as ‘market failure’ or even ‘government failure’. The absence is often attributable to particular technical, economic and political constraints that preclude the operation of markets. Arguably, greater care is needed in distinguishing between the polity and markets in raising revenues and allocating resources; and that needs to start by removing unhelpful references to ‘business’ in the context of government decision-making.

Knowledge is not power, but it’s a start : young people and employment entitlements

This paper employs empirical evidence from a survey of Queensland secondary school students to examine their knowledge about their wages and working conditions. It does so within the theoretical lens of the Gagne (or Gagne-Briggs) theory of instruction, which centres on the content of learning and how learning is acquired (Gagne, Briggs & Wager, 1988). While Gagne articulates five categories of learning, our focus here is on two; verbal information or declarative knowledge (facts that people can declare), and procedural knowledge (the rules and procedures for achieving outcomes). We show that student workers know little about the instruments governing their employment, or their workplace entitlements. Of the total sample of year 9 and year 11 students surveyed (n=892), those students who worked, or who had worked in the past year (n=438), were asked to identify whether they were employed under an award, collective agreement or AWA. Eighty three per cent of students did not know which industrial instrument set their wages. We argue that if young workers do not have declarative knowledge of their entitlements, nor basic procedural knowledge about redress, then they are not in a position to deploy Gagne’s ‘cognitive strategies’ that would enable them to take action to ensure their working conditions meet legal minima. We advocate that young workers should be given summary information on their wages and other entitlements on appointment and that such summary information should be readily available on employers’ noticeboards and electronically on company websites, and that the information should include a brief summary of avenues for redressing issues of underpayment or sub-standard conditions.

Reading the environment : narrative constructions of ecological subjectivities in Australian children's literature

Ways in which humans engage with the environment have always provided a rich source of material for writers and illustrators of Australian children's literature. Currently, readers are confronted with a multiplicity of complex, competing and/or complementing networks of ideas, theories and emotions that provide narratives about human engagement with the environment at a particular historical moment. This study, entitled Reading the Environment: Narrative Constructions of Ecological Subjectivities in Australian Children's Literature, examines how a representative sample of Australian texts (19 picture books and 4 novels for children and young adults published between 1995 and 2006) constructs fictional ecological subjects in the texts, and offers readers ecological subject positions inscribed with contemporary environmental ideologies. The conceptual framework developed in this study identifies three ideologically grounded positions that humans may assume when engaging with the environment. None of these positions clearly exists independently of any other, nor are they internally homogeneous. Nevertheless they can be categorised as: (i) human dominion over the environment with little regard for environmental degradation (unrestrained anthropocentrism); (ii) human consideration for the environment driven by understandings that humans need the environment to survive (restrained anthropocentrism); and (iii) human deference towards the environment guided by understandings that humans are no more important than the environment (ecocentrism). iv The transdisciplinary methodological approach to textual analysis used in this thesis draws on ecocriticism, narrative theories, visual semiotics, ecofeminism and postcolonialism to discuss the difficulties and contradictions in the construction of the positions offered. Each chapter of textual analysis focuses on the construction of subjectivities in relation to one of the positions identified in the conceptual framework. Chapter 5 is concerned with how texts highlight the negative consequences of human dominion over the environment, or, in the words of this study, living with ecocatastrophe. Chapter 6 examines representations of restrained anthropocentrism in its contemporary form, that is, sustainability. Chapter 7 examines representations of ecocentrism, a radical position with inherent difficulties of representation. According to the analysis undertaken, the focus texts convey the subtleties and complexities of human engagement with the environment and advocate ways of viewing and responding to contemporary unease about the environment. The study concludes that these ways of viewing and responding conform to and/or challenge dominant socio-cultural and political-economic opinions regarding the environment. This study, the first extended work of its kind, makes an original contribution to ecocritical study of Australian children's literature. By undertaking a comprehensive analysis of how texts for children represent human engagement with the environment at a time when important environmental concerns pose significant threats to human existence, I hope to contribute new knowledge to an area of children's literature research that to date has been significantly under-represented.