Limits of spherical blur determined with an adaptive optics mirror

We extended an earlier study (Vision Research, 45, 1967–1974, 2005) in which we investigated limits at which induced blur of letter targets becomes noticeable, troublesome and objectionable. Here we used a deformable adaptive optics mirror to vary spherical defocus for conditions of a white background with correction of astigmatism; a white background with reduction of all aberrations other than defocus; and a monochromatic background with reduction of all aberrations other than defocus. We used seven cyclopleged subjects, lines of three high-contrast letters as targets, 3–6 mm artificial pupils, and 0.1–0.6 logMAR letter sizes. Subjects used a method of adjustment to control the defocus component of the mirror to set the 'just noticeable', 'just troublesome' and 'just objectionable' defocus levels. For the white-no adaptive optics condition combined with 0.1 logMAR letter size, mean 'noticeable' blur limits were ±0.30, ±0.24 and ±0.23 D at 3, 4 and 6 mm pupils, respectively. White-adaptive optics and monochromatic-adaptive optics conditions reduced blur limits by 8% and 20%, respectively. Increasing pupil size from 3–6 mm decreased blur limits by 29%, and increasing letter size increased blur limits by 79%. Ratios of troublesome to noticeable, and of objectionable to noticeable, blur limits were 1.9 and 2.7 times, respectively. The study shows that the deformable mirror can be used to vary defocus in vision experiments. Overall, the results of noticeable, troublesome and objectionable blur agreed well with those of the previous study. Attempting to reduce higher-order aberrations or chromatic aberrations, reduced blur limits to only a small extent.

Robust video stabilisation algorithm using feature point selection and delta optical flow

In this study, the authors propose a novel video stabilisation algorithm for mobile platforms with moving objects in the scene. The quality of videos obtained from mobile platforms, such as unmanned airborne vehicles, suffers from jitter caused by several factors. In order to remove this undesired jitter, the accurate estimation of global motion is essential. However it is difficult to estimate global motions accurately from mobile platforms due to increased estimation errors and noises. Additionally, large moving objects in the video scenes contribute to the estimation errors. Currently, only very few motion estimation algorithms have been developed for video scenes collected from mobile platforms, and this paper shows that these algorithms fail when there are large moving objects in the scene. In this study, a theoretical proof is provided which demonstrates that the use of delta optical flow can improve the robustness of video stabilisation in the presence of large moving objects in the scene. The authors also propose to use sorted arrays of local motions and the selection of feature points to separate outliers from inliers. The proposed algorithm is tested over six video sequences, collected from one fixed platform, four mobile platforms and one synthetic video, of which three contain large moving objects. Experiments show our proposed algorithm performs well to all these video sequences.

Participation and social order in the playground

This study investigates the everyday practices of young children acting in their social worlds within the context of the school playground. It employs an ethnographic ethnomethodological approach using conversation analysis. In the context of child participation rights advanced by the United Nations Convention on the Rights of the Child (UNCRC) and childhood studies, the study considers children’s social worlds and their participation agendas. The participants of the study were a group of young children in a preparatory year setting in a Queensland school. These children, aged 4 to 6 years, were videorecorded as they participated in their day-to-day activities in the classroom and in the playground. Data collection took place over a period of three months, with a total of 26 hours of video data. Episodes of the video-recordings were shown to small groups of children and to the teacher to stimulate conversations about what they saw on the video. The conversations were audio-recorded. This method acknowledged the child’s standpoint and positioned children as active participants in accounting for their relationships with others. These accounts are discussed as interactionally built comments on past joint experiences and provided a starting place for analysis of the video-recorded interaction. Four data chapters are presented in this thesis. Each data chapter investigates a different topic of interaction. The topics include how children use “telling” as a tactical tool in the management of interactional trouble, how children use their “ideas” as possessables to gain ownership of a game and the interactional matters that follow, how children account for interactional matters and bid for ownership of “whose idea” for the game and finally, how a small group of girls orientated to a particular code of conduct when accounting for their actions in a pretend game of “school”. Four key themes emerged from the analysis. The first theme addresses two arenas of action operating in the social world of children, pretend and real: the “pretend”, as a player in a pretend game, and the “real”, as a classroom member. These two arenas are intertwined. Through inferences to explicit and implicit “codes of conduct”, moral obligations are invoked as children attempt to socially exclude one another, build alliances and enforce their own social positions. The second theme is the notion of shared history. This theme addresses the history that the children reconstructed, and acts as a thread that weaves through their interactions, with implications for present and future relationships. The third theme is around ownership. In a shared context, such as the playground, ownership is a highly contested issue. Children draw on resources such as rules, their ideas as possessables, and codes of behaviour as devices to construct particular social and moral orders around owners of the game. These themes have consequences for children’s participation in a social group. The fourth theme, methodological in nature, shows how the researcher was viewed as an outsider and novice and was used as a resource by the children. This theme is used to inform adult-child relationships. The study was situated within an interest in participation rights for children and perspectives of children as competent beings. Asking children to account for their participation in playground activities situates children as analysers of their own social worlds and offers adults further information for understanding how children themselves construct their social interactions. While reporting on the experiences of one group of children, this study opens up theoretical questions about children’s social orders and these influences on their everyday practices. This thesis uncovers how children both participate in, and shape, their everyday social worlds through talk and interaction. It investigates the consequences that taken-for-granted activities of “playing the game” have for their social participation in the wider culture of the classroom. Consideration of this significance may assist adults to better understand and appreciate the social worlds of young children in the school playground.

An effective approach to verbose queries using a limited dependencies language model

Intuitively, any `bag of words' approach in IR should benefit from taking term dependencies into account. Unfortunately, for years the results of exploiting such dependencies have been mixed or inconclusive. To improve the situation, this paper shows how the natural language properties of the target documents can be used to transform and enrich the term dependencies to more useful statistics. This is done in three steps. The term co-occurrence statistics of queries and documents are each represented by a Markov chain. The paper proves that such a chain is ergodic, and therefore its asymptotic behavior is unique, stationary, and independent of the initial state. Next, the stationary distribution is taken to model queries and documents, rather than their initial distri- butions. Finally, ranking is achieved following the customary language modeling paradigm. The main contribution of this paper is to argue why the asymptotic behavior of the document model is a better representation then just the document's initial distribution. A secondary contribution is to investigate the practical application of this representation in case the queries become increasingly verbose. In the experiments (based on Lemur's search engine substrate) the default query model was replaced by the stable distribution of the query. Just modeling the query this way already resulted in significant improvements over a standard language model baseline. The results were on a par or better than more sophisticated algorithms that use fine-tuned parameters or extensive training. Moreover, the more verbose the query, the more effective the approach seems to become.

The Autistic Behavioural Indicators Instrument (ABII) : development and instrument utility in discriminating autistic disorder from speech and language impairment and typical development

The Autistic Behavioural Indicators Instrument (ABII) is an 18-item instrument developed to identify children with Autistic Disorder (AD) based on the presence of unique autistic behavioural indicators. The ABII was administered to 20 children with AD, 20 children with speech and language impairment (SLI) and 20 typically developing (TD) children aged 2-6 years. Results indicated that the ABII discriminated children diagnosed with AD from those diagnosed with SLI and those who were TD, based on the presence of specific social attention, sensory, and behavioural symptoms. A combination of symptomology across these domains correctly classified 100% of children with and without AD. The paper concludes that the ABII shows considerable promise as an instrument for the early identification of AD.

Tag based collaborative filtering for recommender systems

Collaborative tagging can help users organize, share and retrieve information in an easy and quick way. For the collaborative tagging information implies user’s important personal preference information, it can be used to recommend personalized items to users. This paper proposes a novel tag-based collaborative filtering approach for recommending personalized items to users of online communities that are equipped with tagging facilities. Based on the distinctive three dimensional relationships among users, tags and items, a new similarity measure method is proposed to generate the neighborhood of users with similar tagging behavior instead of similar implicit ratings. The promising experiment result shows that by using the tagging information the proposed approach outperforms the standard user and item based collaborative filtering approaches.

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.

Queering cyberspace : fan fiction communities as spaces for expressing and exploring sexuality

The social construction of sexuality over the past one hundred and fifty years has created a dichotomy between heterosexual and non-heterosexual identities that essentially positions the former as “normal” and the latter as deviant. Even Kinsey’s and others’ work on the continuum of sexualities did little to alter the predominantly heterosexist perception of the non-heterosexual as “other” (Kinsey, Pomeroy and Martin 2007; Esterberg 2006; Franceour and Noonan 2007). Some political action and academic work is beginning to challenge such perceptions. Even some avenues of social interaction, such as the recent proliferation of online communities, may also challenge such views, or at least contribute to their being rethought in some ways. This chapter explores a specific kind of online community devoted to fan fiction, specifically homoerotic – or what is known colloquially as “slash” – fan fiction. Fan fiction is fiction, published on the internet, and written by fans of well-known books and television shows, using the characters to create new and varied plots. “Slash” refers to the pairing of two of the male characters in a romantic relationship, and the term comes from the punctuation mark dividing the named pair as, for example, Spock/Kirk from the Star Trek television series. Although there are some slash fan-fiction stories devoted to female-female relationships – called “femmeslash” – the term “slash” generally refers to male-male relationships, and will be utilized throughout this chapter, given that the research discussed focuses on communities centered around one such male pairing.

Investigating the use of association rules in improving recommender systems

Recommender systems are widely used online to help users find other products, items etc that they may be interested in based on what is known about that user in their profile. Often however user profiles may be short on information and thus when there is not sufficient knowledge on a user it is difficult for a recommender system to make quality recommendations. This problem is often referred to as the cold-start problem. Here we investigate whether association rules can be used as a source of information to expand a user profile and thus avoid this problem, leading to improved recommendations to users. Our pilot study shows that indeed it is possible to use association rules to improve the performance of a recommender system. This we believe can lead to further work in utilising appropriate association rules to lessen the impact of the cold-start problem.

Trends in demographic, health behaviour factors, and self-perceived weight status : influences on obesity in Australia from 1995 to 2005

Overweight and obesity are two of the most important emerging public health issues in our time and regarded by the World Health Organisation [WHO] (1998) as a worldwide epidemic. The prevalence of obesity in the USA is the highest in the world, and Australian obesity rates fall into second place. Currently, about 60% of Australian adults are overweight (BMI „d 25kg/m2). The socio-demographic factors associated with overweight and/or obesity have been well demonstrated, but many of the existing studies only examined these relationships at one point of time, and did not examine whether significant relationships changed over time. Furthermore, only limited previous research has examined the issue of the relationship between perception of weight status and actual weight status, as well as factors that may impact on people¡¦s perception of their body weight status. Aims: The aims of the proposed research are to analyse the discrepancy between perceptions of weight status and actual weight status in Australian adults; to examine if there are trends in perceptions of weight status in adults between 1995 to 2004/5; and to propose a range of health promotion strategies and furth er research that may be useful in managing physical activity, healthy diet, and weight reduction. Hypotheses: Four alternate hypotheses are examined by the research: (1) there are associations between independent variables (e.g. socio -demographic factors, physical activity and dietary habits) and overweight and/or obesity; (2) there are associations between the same independent variables and the perception of overweight; (3) there are associations between the same independent variables and the discrepancy between weight status and perception of weight status; and (4) there are trends in overweight and/or obesity, perception of overweight, and the discrepancy in Australian adults from 1995 to 2004/5. Conceptual Framework and Methods: A conceptual framework is developed that shows the associations identified among socio -demographic factors, physical activity and dietary habits with actual weight status, as well as examining perception of weight status. The three latest National Health Survey data bases (1995 , 2001 and 2004/5) were used as the primary data sources. A total of 74,114 Australian adults aged 20 years and over were recruited from these databases. Descriptive statistics, bivariate analyses (One -Way ANOVA tests, unpaired t-tests and Pearson chi-square tests), and multinomial logistic regression modelling were used to analyse the data. Findings: This research reveals that gender, main language spoken at home, occupation status, household structure, private health insurance status, and exercise are related to the discrepancy between actual weight status and perception of weight status, but only gender and exercise are related to the discrepancy across the three time point s. The current research provides more knowledge about perception of weight status independently. Factors which affect perception of overweight are gender, age, language spoken at home, private health insurance status, and diet ary habits. The study also finds that many factors that impact overweight and/or obesity also have an effect on perception of overweight, such as age, language spoken at home, household structure, and exercise. However, some factors (i.e. private health insurance status and milk consumption) only impact on perception of overweight. Furthermore, factors that are rel ated to people’s overweight are not totally related to people’s underestimation of their body weight status in the study results. Thus, there are unknown factors which can affect people’s underestimation of their body weight status. Conclusions: Health promotion and education activities should provide education about population health education and promotion and education for particular at risk sub -groups. Further research should take the form of a longitudinal study design ed to examine the causal relationship between overweight and/or obesity and underestimation of body weight status, it should also place more attention on the relationships between overweight and/or obesity and dietary habits, with a more comprehensive representation of SES. Moreover, further research that deals with identification of characteristics about perception of weight status, in particular the underestimation of body weight status should be undertaken.

Innovation and the city : a macromarketing approach to industry development

Purpose – The purpose of this paper is to propose and demonstrate the relevance of marketing systems, notably the process of product management and innovation, to urban development challenges. Design/methodology/approach – A macromarketing perspective is adopted to construe the city as a product and begin the application of the innovation process to urban management, following the steps commonly proposed for successful innovation in product management. An example of the application of the initial new product development steps of idea generation and opportunity identification is presented. Findings – The innovation process provides guidelines and checkpoints that enable corporations to improve the success rate of their development initiatives. Cities, like corporations, need to innovate in order to maintain their image and functionality, to provide a myriad benefits to their stakeholders and, thereby, to survive and grow. The example here shows how the preliminary NPD steps of idea generation and opportunity identification enrich the process of identifying and analysing new industry opportunities for a city. Practical implications – By conceptualising the city as a multifaceted product, the disciplined planning and evaluation processes pertinent to NPD success become relevant and helpful to practitioners responsible for urban planning, urban development and change. Originality/value – The paper shows how pertinent concepts and processes from marketing can be effectively applied to urban planning and economic development initiatives.

Cost-effectiveness of a telephone-delivered intervention for physical activity and diet

Background: Given escalating rates of chronic disease, broad-reach and cost-effective interventions to increase physical activity and improve dietary intake are needed. The cost-effectiveness of a Telephone Counselling intervention to improve physical activity and diet, targeting adults with established chronic diseases in a low socio-economic area of a major Australian city was examined. Methodology/Principal Findings: A cost-effectiveness modelling study using data collected between February 2005 and November 2007 from a cluster-randomised trial that compared Telephone Counselling with a “Usual Care” (brief intervention) alternative. Economic outcomes were assessed using a state-transition Markov model, which predicted the progress of participants through five health states relating to physical activity and dietary improvement, for ten years after recruitment. The costs and health benefits of Telephone Counselling, Usual Care and an existing practice (Real Control) group were compared. Telephone Counselling compared to Usual Care was not cost-effective ($78,489 per quality adjusted life year gained). However, the Usual Care group did not represent existing practice and is not a useful comparator for decision making. Comparing Telephone Counselling outcomes to existing practice (Real Control), the intervention was found to be cost-effective ($29,375 per quality adjusted life year gained). Usual Care (brief intervention) compared to existing practice (Real Control) was also cost-effective ($12,153 per quality adjusted life year gained). Conclusions/Significance: This modelling study shows that a decision to adopt a Telephone Counselling program over existing practice (Real Control) is likely to be cost-effective. Choosing the ‘Usual Care’ brief intervention over existing practice (Real Control) shows a lower cost per quality adjusted life year, but the lack of supporting evidence for efficacy or sustainability is an important consideration for decision makers. The economics of behavioural approaches to improving health must be made explicit if decision makers are to be convinced that allocating resources toward such programs is worthwhile.

Homegardening as a panacea : a case study of South Tarawa

The Republic of Kiribati is a small, highly infertile Pacific Island nation and is one of the most challenging locations to attempt to support dense urban populations. Kiribati, like other nations in the Pacific, faces an urban future where food insecurity, unemployment, waste management and malnutrition will become increasing issues. Homegardening is suggested as one way to address many of these problems. However, the most recent study on agriculture production in urban centres in Kiribati shows that, in general, intensive cultivation of homegardens is not a common practice. This disparity between theory and practice creates an opportunity to re-examine homegardening in Kiribati and, more broadly, in the Pacific. This paper examines the practice of homegardening in urban centres in Kiribati and explores reasons why change has or has not occurred through interviews with homegardeners and government/donor representives. Results show that homegardening has increased significantly in the past five years, largely because of the promotion of homegardens and organic composting systems by donor organisations. While findings further endorse homegardening as an excellent theoretical solution to many of the problems that confront urban settlements in Kiribati and the Pacific, it raises additional questions regarding the continuation of homegarden schemes beyond donor support programmes.

Are country and cultural values interchangeable? : a case example using occupational stress and coping

Cross-cultural research in occupational stress and coping has produced a wealth of knowledge. Although advancement has been made, there are still problems to be solved. One of these problems is the confusion generated in the literature by researchers claiming nation or country as representing cultural values, and the use of the two terms interchangeably. It remains unclear whether this practice is correct. The present paper reported on this by using 511 full time employees from Australia, Singapore and Sri Lanka to study occupational stress and coping. Results revealed that cultural value paradigm (i.e., Individualism-Collectivism) was distributed across the three nations, such that over 60% of participants across the three nations were either high or low in both I-C paradigms. The findings also indicated that the relationship between cultural value paradigm and country impacted on stress and coping differently. The study shows that significant differences exist within country, as well as between countries, such that any attempt to equate ‘culture’ with ‘country’ becomes problematic. Therefore, these findings establish that country or nation was not the same as culture values and could not be used interchangeably.

Spatial analysis of notified cryptosporidiosis infections in Brisbane, Australia

Purpose: This study explored the spatial distribution of notified cryptosporidiosis cases and identified major socioeconomic factors associated with the transmission of cryptosporidiosis in Brisbane, Australia. Methods: We obtained the computerized data sets on the notified cryptosporidiosis cases and their key socioeconomic factors by statistical local area (SLA) in Brisbane for the period of 1996 to 2004 from the Queensland Department of Health and Australian Bureau of Statistics, respectively. We used spatial empirical Bayes rates smoothing to estimate the spatial distribution of cryptosporidiosis cases. A spatial classification and regression tree (CART) model was developed to explore the relationship between socioeconomic factors and the incidence rates of cryptosporidiosis. Results: Spatial empirical Bayes analysis reveals that the cryptosporidiosis infections were primarily concentrated in the northwest and southeast of Brisbane. A spatial CART model shows that the relative risk for cryptosporidiosis transmission was 2.4 when the value of the social economic index for areas (SEIFA) was over 1028 and the proportion of residents with low educational attainment in an SLA exceeded 8.8%. Conclusions: There was remarkable variation in spatial distribution of cryptosporidiosis infections in Brisbane. Spatial pattern of cryptosporidiosis seems to be associated with SEIFA and the proportion of residents with low education attainment.