Bearing-only SLAM : a vision-based navigation system for autonomous robots

To navigate successfully in a previously unexplored environment, a mobile robot must be able to estimate the spatial relationships of the objects of interest accurately. A Simultaneous Localization and Mapping (SLAM) sys- tem employs its sensors to build incrementally a map of its surroundings and to localize itself in the map simultaneously. The aim of this research project is to develop a SLAM system suitable for self propelled household lawnmowers. The proposed bearing-only SLAM system requires only an omnidirec- tional camera and some inexpensive landmarks. The main advantage of an omnidirectional camera is the panoramic view of all the landmarks in the scene. Placing landmarks in a lawn field to define the working domain is much easier and more flexible than installing the perimeter wire required by existing autonomous lawnmowers. The common approach of existing bearing-only SLAM methods relies on a motion model for predicting the robot’s pose and a sensor model for updating the pose. In the motion model, the error on the estimates of object positions is cumulated due mainly to the wheel slippage. Quantifying accu- rately the uncertainty of object positions is a fundamental requirement. In bearing-only SLAM, the Probability Density Function (PDF) of landmark position should be uniform along the observed bearing. Existing methods that approximate the PDF with a Gaussian estimation do not satisfy this uniformity requirement. This thesis introduces both geometric and proba- bilistic methods to address the above problems. The main novel contribu- tions of this thesis are: 1. A bearing-only SLAM method not requiring odometry. The proposed method relies solely on the sensor model (landmark bearings only) without relying on the motion model (odometry). The uncertainty of the estimated landmark positions depends on the vision error only, instead of the combination of both odometry and vision errors. 2. The transformation of the spatial uncertainty of objects. This thesis introduces a novel method for translating the spatial un- certainty of objects estimated from a moving frame attached to the robot into the global frame attached to the static landmarks in the environment. 3. The characterization of an improved PDF for representing landmark position in bearing-only SLAM. The proposed PDF is expressed in polar coordinates, and the marginal probability on range is constrained to be uniform. Compared to the PDF estimated from a mixture of Gaussians, the PDF developed here has far fewer parameters and can be easily adopted in a probabilistic framework, such as a particle filtering system. The main advantages of our proposed bearing-only SLAM system are its lower production cost and flexibility of use. The proposed system can be adopted in other domestic robots as well, such as vacuum cleaners or robotic toys when terrain is essentially 2D.

An analysis and comparison of rural land sales

Rural land prices, in developed, free trade real estate markets, are influenced not only by prevailing economic conditions but also physical factors such as climate, topography and soil type. In broad acre farming and grazing operations, both commodity price and yields determine farm income. Yields, in turn, are a function of climate, topography and soil type. The strength of a rural land market is influenced by the overall rural economy in a Country, State or region. These differences in rural land markets can also vary within smaller regions. It has been held that rural land, in relative safe production areas, is less effected by adverse economic and climatic factors than land in more marginal agricultural areas. This paper will analyse rural land sales in both traditional cropping areas and marginal cropping areas for the period 1975 to 1996. The analysis will determine the overall trend in rural land prices over the period, compare the average annual return between marginal and established farming areas and determine which economic and production factors have influenced this change. The impact of this analysis will also be discussed in relation to rural land appraisal.

The studio sans frontières : the open-studio as an answer to the challenges of teaching contemporary art

Since at least the 1960s, art has assumed a breadth of form and medium as diverse as social reality itself. Where once it was marginal and transgressive for artists to work across a spectrum of media, today it is common practice. In this ‘post-medium’ age, fidelity to a specific branch of media is a matter of preference, rather than a code of practice policed by gallerists, curators and critics. Despite the openness of contemporary art practice, the teaching of art at most universities remains steadfastly discipline-based. Discipline-based art teaching, while offering the promise of focussed ‘mastery’ of a particular set of technical skills and theoretical concerns, does so at the expense of a deeper and more complex understanding of the possibilities of creative experimentation in the artist’s studio. By maintaining an hermetic approach to medium, it does not prepare students sufficiently for the reality of art making in the twenty-first century. In fact, by pretending that there is a select range of techniques fundamental to the artist’s trade, discipline-based teaching can often appear to be more engaged with the notion of skills preservation than purposeful art training. If art schools are to survive and prosper in an increasingly vocationally-oriented university environment, they need to fully synthesise the professional reality of contemporary art practice into their approach to teaching and learning. This paper discusses the way in which the ‘open’ studio approach to visual art study at QUT endeavours to incorporate the diversity and complexity of contemporary art while preserving the sense of collective purpose that discipline-based teaching fosters. By allowing students to independently develop their own art practices while also applying collaborative models of learning and assessment, the QUT studio program aims to equip students with a strong sense of self-reliance, a broad awareness and appreciation of contemporary art, and a deep understanding of studio-based experimentation unfettered by the boundaries of traditional media: all skills fundamental to the practice of contemporary art.

Inhibition of myeloperoxidase-mediated hypochlorous acid production by nitroxides

Tissue damage resulting from the extracellular production of HOCl (hypochlorous acid) by the MPO (myeloperoxidase)-hydrogen peroxide-chloride system of activated phagocytes is implicated as a key event in the progression of a number of human inflammatory diseases. Consequently, there is considerable interest in the development of therapeutically useful MPO inhibitors. Nitroxides are well established antioxidant compounds of low toxicity that can attenuate oxidative damage in animal models of inflammatory disease. They are believed to exert protective effects principally by acting as superoxide dismutase mimetics or radical scavengers. However, we show here that nitroxides can also potently inhibit MPO-mediated HOCl production, with the nitroxide 4-aminoTEMPO inhibiting HOCl production by MPO and by neutrophils with IC50 values of approx. 1 and 6 μM respectively. Structure–activity relationships were determined for a range of aliphatic and aromatic nitroxides, and inhibition of oxidative damage to two biologically-important protein targets (albumin and perlecan) are demonstrated. Inhibition was shown to involve one-electron oxidation of the nitroxides by the compound I form of MPO and accumulation of compound II. Haem destruction was also observed with some nitroxides. Inhibition of neutrophil HOCl production by nitroxides was antagonized by neutrophil-derived superoxide, with this attributed to superoxide-mediated reduction of compound II. This effect was marginal with 4-aminoTEMPO, probably due to the efficient superoxide dismutase-mimetic activity of this nitroxide. Overall, these data indicate that nitroxides have considerable promise as therapeutic agents for the inhibition of MPO-mediated damage in inflammatory diseases.

Bayes factor based speaker clustering for speaker diarization

This paper proposes the use of the Bayes Factor to replace the Bayesian Information Criterion (BIC) as a criterion for speaker clustering within a speaker diarization system. The BIC is one of the most popular decision criteria used in speaker diarization systems today. However, it will be shown in this paper that the BIC is only an approximation to the Bayes factor of marginal likelihoods of the data given each hypothesis. This paper uses the Bayes factor directly as a decision criterion for speaker clustering, thus removing the error introduced by the BIC approximation. Results obtained on the 2002 Rich Transcription (RT-02) Evaluation dataset show an improved clustering performance, leading to a 14.7% relative improvement in the overall Diarization Error Rate (DER) compared to the baseline system.

Customer-oriented deviance (COD) : a conceptualisation, development and validation of a behavioural measure

Frontline employee behaviours are recognised as vital for achieving a competitive advantage for service organisations. The services marketing literature has comprehensively examined ways to improve frontline employee behaviours in service delivery and recovery. However, limited attention has been paid to frontline employee behaviours that favour customers in ways that go against organisational norms or rules. This study examines these behaviours by introducing a behavioural concept of Customer-Oriented Deviance (COD). COD is defined as, “frontline employees exhibiting extra-role behaviours that they perceive to defy existing expectations or prescribed rules of higher authority through service adaptation, communication and use of resources to benefit customers during interpersonal service encounters.” This thesis develops a COD measure and examines the key determinants of these behaviours from a frontline employee perspective. Existing research on similar behaviours that has originated in the positive deviance and pro-social behaviour domains has limitations and is considered inadequate to examine COD in the services context. The absence of a well-developed body of knowledge on non-conforming service behaviours has implications for both theory and practice. The provision of ‘special favours’ increases customer satisfaction but the over-servicing of customers is also counterproductive for the service delivery and costly for the organisation. Despite these implications of non-conforming service behaviours, there is little understanding about the nature of these behaviours and its key drivers. This research builds on inadequacies in prior research on positive deviance, pro-social and pro-customer literature to develop the theoretical foundation of COD. The concept of positive deviance which has predominantly been used to study organisational behaviours is applied within a services marketing setting. Further, it addresses previous limitations in pro-social and pro-customer behavioural literature that has examined limited forms of behaviours with no clear understanding on the nature of these behaviours. Building upon these literature streams, this research adopts a holistic approach towards the conceptualisation of COD. It addresses previous shortcomings in the literature by providing a well bounded definition, developing a psychometrically sound measure of COD and a conceptually well-founded model of COD. The concept of COD was examined across three separate studies and based on the theoretical foundations of role theory and social identity theory. Study 1 was exploratory and based on in-depth interviews using the Critical Incident Technique (CIT). The aim of Study 1 was to understand the nature of COD and qualitatively identify its key drivers. Thematic analysis was conducted to analyse the data and the two potential dimensions of COD behaviours of Deviant Service Adaptation (DSA) and Deviant Service Communication (DSC) were revealed in the analysis. In addition, themes representing the potential influences of COD were broadly classified as individual factors, situational factors, and organisational factors. Study 2 was a scale development procedure that involved the generation and purification of items for the measure based on two student samples working in customer service roles (Pilot sample, N=278; Initial validation sample, N=231). The results for the reliability and Exploratory Factor Analyses (EFA) on the pilot sample suggested the scale had poor psychometric properties. As a result, major revisions were made in terms of item wordings and new items were developed based on the literature to reflect a new dimension, Deviant Use of Resources (DUR). The revised items were tested on the initial validation sample with the EFA analysis suggesting a four-factor structure of COD. The aim of Study 3 was to further purify the COD measure and test for nomological validity based on its theoretical relationships with key antecedents and similar constructs (key correlates). The theoretical model of COD consisting of nine hypotheses was tested on a retail and hospitality sample of frontline employees (Retail N=311; Hospitality N=305) of a market research panel using an online survey. The data was analysed using Structural Equation Modelling (SEM). The results provided support for a re-specified second-order three-factor model of COD which consists of 11 items. Overall, the COD measure was found to be reliable and valid, demonstrating convergent validity, discriminant validity and marginal partial invariance for the factor loadings. The results showed support for nomological validity, although the antecedents had differing impact on COD across samples. Specifically, empathy and perspective-taking, role conflict, and job autonomy significantly influenced COD in the retail sample, whereas empathy and perspective-taking, risk-taking propensity and role conflict were significant predictors in the hospitality sample. In addition, customer orientation-selling orientation, the altruistic dimension of organisational citizenship behaviours, workplace deviance, and social desirability responding were found to correlate with COD. This research makes several contributions to theory. First, the findings of this thesis extend the literature on positive deviance, pro-social and pro-customer behaviours. Second, the research provides an empirically tested model which describes the antecedents of COD. Third, this research contributes by providing a reliable and valid measure of COD. Finally, the research investigates the differential effects of the key antecedents in different service sectors on COD. The research findings also contribute to services marketing practice. Based on the research findings, service practitioners can better understand the phenomenon of COD and utilise the measurement tool to calibrate COD levels within their organisations. Knowledge on the key determinants of COD will help improve recruitment and training programs and drive internal initiatives within the firm.

The Sun gives without ever receiving

A small scale sculpture that contributes towards my ongoing explorations into how our collective ability to sustain (the future) is as much a cultural problematic as it is an economic or technological one. The curatorial brief of the project was a technical one - in that each curated artist was to design a piece in CAD suitable for 3D resin printing - The object should be entirely generated through 3D visualisation and modelling tools and should be machined and shipped within the dimensions of 6cm x 6cm x 6cm. My design for this brief was influenced by recent research I had conducted in Mildura in the Sunraysia irrigated region of NW Victoria. Each name set within the work is an Australian soldier/settler – who, on returning from the ‘Great War’ was duly awarded a ‘block’ in Australia’s new inland irrigated settlements - with the explicit task of clearing it to plant and reap. Through their concerted and well-intentioned efforts, these workers began to profoundly re-shape Australia’s marginal country - inadvertently presaging the bleak future faced today by many of Australia’s inland lands and river systems. Furthermore, through that time's predominant colonial conception of ‘terra nullius’ (this land is unoccupied and therefore free to be claimed) they each played a small but formative part in building the profound cultural divide between land and peoples that still haunts Australia today. THE EXHIBITION: Inside Out is a compelling international touring exhibition featuring forty-six miniature sculptures produced in resin using 3D printing technologies. Developments in virtual computer visualisation and integrated digital technologies are giving contemporary makers new insight and opportunities to create objects and forms which were previously impossible to produce or difficult to envisage. The exhibition is the result of collaboration between the Art Technology Coalition, the University of Technology Sydney and RMIT University in Australia along with De Montfort University, Manchester Metropolitan University and Dartington College of Arts at University College Falmouth in the United Kingdom.

An assessment of construction labour productivity in Malaysia

The construction industry is one of major strategic importance. Its level of productivity has a significant effect on national economic growth. The analysis of published census/biannual surveys of construction by the Department of Statistics of Malaysia shows that Malaysia managed to achieve construction labour productivity growth between 1996 and 2005 despite increases in cost per employee. The decrease in unit labour costs is attributed to the value added improvement per worker through the increase in capital intensity. The marginal decline in capital productivity is due to the gestation period and the overcapacity of the industry. The civil engineering sub-sector recorded the highest labour productivity and is the most labour competitive in terms of unit labour cost and added value per labour cost. The residential sub-sectors recorded greatest change in the productivity indicators between 1996 and 2005.

Mental health outcomes for unemployed individuals who attend occupational skills / personal development training programs

Four studies report on outcomes for long-term unemployed individuals who attend occupational skills/personal development training courses in Australia. Levels of distress, depression, guilt, anger, helplessness, positive and negative affect, life satisfaction and self esteem were used as measures of well-being. Employment value, employment expectations and employment commitment were used as measures of work attitude. Social support, financial strain, and use of community resources were used as measures of life situation. Other variables investigated were causal attribution, unemployment blame, levels of coping, self efficacy, the personality variable of neuroticism, the psycho-social climate of the training course, and changes to occupational status. Training courses were (a) government funded occupational skills-based programs which included some components of personal development training, and (b) a specially developed course which focused exclusively on improving well-being, and which utilised the cognitive-behavioural therapy (CBT) approach. Data for all studies were collected longitudinally by having subjects complete questionnaires pre-course, post-course, and (for 3 of the 4 studies) at 3 months follow-up, in order to investigate long-term effects. One of the studies utilised the case-study methodology and was designed to be illustrative and assist in interpreting the quantitative data from the other 3 evaluations. The outcomes for participants were contrasted with control subjects who met the same sel~tion criteria for training. Results confirmed earlier findings that the experiences of unemployment were negative. Immediate effects of the courses were to improve well-being. Improvements were greater for those who attended courses with higher levels of personal development input, and the best results were obtained from the specially developed CBT program. Participants who had lower levels of well-being at the beginning of the courses did better as a result of training than those who were already functioning at higher levels. Course participants gained only marginal advantages over control subjects in relation to improving their occupational status. Many of the short term well-being gains made as a result of attending the courses were still evident at 3 months follow-up. Best results were achieved for the specially designed CBT program. Results were discussed in the context of prevailing theories of Ynemployment (Fryer, 1986,1988; Jahoda, 1981, 1982; Warr, 1987a, 1987b).

Markov modelling of the IEEE 802.11 DCF for real-time applications with periodic traffic

Popular wireless network standards, such as IEEE 802.11/15/16, are increasingly adopted in real-time control systems. However, they are not designed for real-time applications. Therefore, the performance of such wireless networks needs to be carefully evaluated before the systems are implemented and deployed. While efforts have been made to model general wireless networks with completely random traffic generation, there is a lack of theoretical investigations into the modelling of wireless networks with periodic real-time traffic. Considering the widely used IEEE 802.11 standard, with the focus on its distributed coordination function (DCF), for soft-real-time control applications, this paper develops an analytical Markov model to quantitatively evaluate the network quality-of-service (QoS) performance in periodic real-time traffic environments. Performance indices to be evaluated include throughput capacity, transmission delay and packet loss ratio, which are crucial for real-time QoS guarantee in real-time control applications. They are derived under the critical real-time traffic condition, which is formally defined in this paper to characterize the marginal satisfaction of real-time performance constraints.

The urban littoral frontier : land reclamation in the history of human settlements

The urban waterfront may be regarded as the littoral frontier of human settlement. Typically, over the years, it advances, sometimes retreats, where terrestrial and aquatic processes interact and frequently contest this margin of occupation. Because most towns and cities are sited beside water bodies, many of these urban centers on or close to the sea, their physical expansion is constrained by the existence of aquatic areas in one or more directions from the core. It is usually much easier for new urban development to occur along or inland from the waterfront. Where other physical constraints, such as rugged hills or mountains, make expansion difficult or expensive, building at greater densities or construction on steep slopes is a common response. This kind of development, though technically feasible, is usually more expensive than construction on level or gently sloping land, however. Moreover, there are many reasons for developing along the shore or riverfront in preference to using sites further inland. The high cost of developing existing dry land that presents serious construction difficulties is one reason for creating new land from adjacent areas that are permanently or periodically under water. Another reason is the relatively high value of artificially created land close to the urban centre when compared with the value of existing developable space at a greater distance inland. The creation of space for development is not the only motivation for urban expansion into aquatic areas. Commonly, urban places on the margins of the sea, estuaries, rivers or great lakes are, or were once, ports where shipping played an important role in the economy. The demand for deep waterfronts to allow ships to berth and for adjacent space to accommodate various port facilities has encouraged the advance of the urban land area across marginal shallows in ports around the world. The space and locational demands of port related industry and commerce, too, have contributed to this process. Often closely related to these developments is the generation of waste, including domestic refuse, unwanted industrial by-products, site formation and demolition debris and harbor dredgings. From ancient times, the foreshore has been used as a disposal area for waste from nearby settlements, a practice that continues on a huge scale today. Land formed in this way has long been used for urban development, despite problems that can arise from the nature of the dumped material and the way in which it is deposited. Disposal of waste material is a major factor in the creation of new urban land. Pollution of the foreshore and other water margin wetlands in this way encouraged the idea that the reclamation of these areas may be desirable on public health grounds. With reference to examples from various parts of the world, the historical development of the urban littoral frontier and its effects on the morphology and character of towns and cities are illustrated and discussed. The threat of rising sea levels and the heritage value of many waterfront areas are other considerations that are addressed.

"Criatividade na Educação e Formação de Talentos" (Creativity in Education and Development of Talent)

Historically, 'Creativity' has had a complex set of meanings. Not long ago, 'Creativity' had a kind of marginal or peripheral status, being seen as the province of a gifted few; in many cases it was associated almost exclusively with the arts and with artists. But these traditional attitudes to creativity are changing. Mainstream businesses are employing people with creative skills as diverse as writing, directing, graphic design and event management. So what we’re beginning to see is an innovation framework and creative content adding value not just to SMEs, but to traditional industries such as manufacturing and mining, and to wider service industries. And this is why Education is such an important element, particularly with a focus on innovation, and on creative people and the contributions they make across different parts of the economy.

Empirical Bayes method in the study of traffic safety via heterogeneous negative multinomial model

In the study of traffic safety, expected crash frequencies across sites are generally estimated via the negative binomial model, assuming time invariant safety. Since the time invariant safety assumption may be invalid, Hauer (1997) proposed a modified empirical Bayes (EB) method. Despite the modification, no attempts have been made to examine the generalisable form of the marginal distribution resulting from the modified EB framework. Because the hyper-parameters needed to apply the modified EB method are not readily available, an assessment is lacking on how accurately the modified EB method estimates safety in the presence of the time variant safety and regression-to-the-mean (RTM) effects. This study derives the closed form marginal distribution, and reveals that the marginal distribution in the modified EB method is equivalent to the negative multinomial (NM) distribution, which is essentially the same as the likelihood function used in the random effects Poisson model. As a result, this study shows that the gamma posterior distribution from the multivariate Poisson-gamma mixture can be estimated using the NM model or the random effects Poisson model. This study also shows that the estimation errors from the modified EB method are systematically smaller than those from the comparison group method by simultaneously accounting for the RTM and time variant safety effects. Hence, the modified EB method via the NM model is a generalisable method for estimating safety in the presence of the time variant safety and the RTM effects.

The sun gives without ever receiving

YEAR: 2010 ROLE: Artist FORMAT: Miniature 3D Sculpture produced in resin using 3D printing technologies. WITH: International Touring Show ‘Inside Out’ WHAT: A miniature sculpture that contributes towards my ongoing explorations into how our collective ability to sustain (the future) is as much a cultural problematic as it is an economic or technological one. OVERVIEW: The curatorial brief was for each curated artist was to design a piece in CAD suitable for 3D resin printing - The object should be entirely generated through 3D visualisation and modelling tools and should be machined and shipped within the dimensions of 6cm x 6cm x 6cm. My design for this brief was influenced by recent research I had conducted in Mildura in the Sunraysia irrigated region of NW Victoria. Each name set within the work is an Australian soldier/settler – who, on returning from the ‘Great War’ was duly awarded a ‘block’ in Australia’s new inland irrigated settlements - with the explicit task of clearing it to plant and reap. Through their concerted and well-intentioned efforts, these workers began to profoundly re-shape Australia’s marginal country - inadvertently presaging the bleak future faced today by many of Australia’s inland lands and river systems. Furthermore, through that time's predominant colonial conception of ‘terra nullius’ (this land is unoccupied and therefore free to be claimed) they each played a small but formative part in building the profound cultural divide between land and peoples that still haunts Australia today. THE EXHIBITION: Inside Out is a compelling international touring exhibition featuring forty-six miniature sculptures produced in resin using 3D printing technologies. Developments in virtual computer visualisation and integrated digital technologies are giving contemporary makers new insight and opportunities to create objects and forms which were previously impossible to produce or difficult to envisage. The exhibition is the result of collaboration between the Art Technology Coalition, the University of Technology Sydney and RMIT University in Australia along with De Montfort University, Manchester Metropolitan University and Dartington College of Arts at University College Falmouth in the United Kingdom.