Ocular characteristics of anisometropia

Animal models of refractive error development have demonstrated that visual experience influences ocular growth. In a variety of species, axial anisometropia (i.e. a difference in the length of the two eyes) can be induced through unilateral occlusion, image degradation or optical manipulation. In humans, anisometropia may occur in isolation or in association with amblyopia, strabismus or unilateral pathology. Non-amblyopic myopic anisometropia represents an interesting anomaly of ocular growth, since the two eyes within one visual system have grown to different endpoints. These experiments have investigated a range of biometric, optical and mechanical properties of anisometropic eyes (with and without amblyopia) with the aim of improving our current understanding of asymmetric refractive error development. In the first experiment, the interocular symmetry in 34 non-amblyopic myopic anisometropes (31 Asian, 3 Caucasian) was examined during relaxed accommodation. A high degree of symmetry was observed between the fellow eyes for a range of optical, biometric and biomechanical measurements. When the magnitude of anisometropia exceeded 1.75 D, the more myopic eye was almost always the sighting dominant eye. Further analysis of the optical and biometric properties of the dominant and non-dominant eyes was conducted to determine any related factors but no significant interocular differences were observed with respect to best-corrected visual acuity, corneal or total ocular aberrations during relaxed accommodation. Given the high degree of symmetry observed between the fellow eyes during distance viewing in the first experiment and the strong association previously reported between near work and myopia development, the aim of the second experiment was to investigate the symmetry between the fellow eyes of the same 34 myopic anisometropes following a period of near work. Symmetrical changes in corneal and total ocular aberrations were observed following a short reading task (10 minutes, 2.5 D accommodation demand) which was attributed to the high degree of interocular symmetry for measures of anterior eye morphology, and corneal biomechanics. These changes were related to eyelid shape and position during downward gaze, but gave no clear indication of factors associated with near work that might cause asymmetric eye growth within an individual. Since the influence of near work on eye growth is likely to be most obvious during, rather than following near tasks, in the third experiment the interocular symmetry of the optical and biometric changes was examined during accommodation for 11 myopic anisometropes. The changes in anterior eye biometrics associated with accommodation were again similar between the eyes, resulting in symmetrical changes in the optical characteristics. However, the more myopic eyes exhibited slightly greater amounts of axial elongation during accommodation which may be related to the force exerted by the ciliary muscle. This small asymmetry in axial elongation we observed between the eyes may be due to interocular differences in posterior eye structure, given that the accommodative response was equal between eyes. Using ocular coherence tomography a reduced average choroidal thickness was observed in the more myopic eyes compared to the less myopic eyes of these subjects. The interocular difference in choroidal thickness was correlated with the magnitude of spherical equivalent and axial anisometropia. The symmetry in optics and biometrics between fellow eyes which have undergone significantly different visual development (i.e. anisometropic subjects with amblyopia) is also of interest with respect to refractive error development. In the final experiment the influence of altered visual experience upon corneal and ocular higher-order aberrations was investigated in 21 amblyopic subjects (8 refractive, 11 strabismic and 2 form deprivation). Significant differences in aberrations were observed between the fellow eyes, which varied according to the type of amblyopia. Refractive amblyopes displayed significantly higher levels of 4th order corneal aberrations (spherical aberration and secondary astigmatism) in the amblyopic eye compared to the fellow non-amblyopic eye. Strabismic amblyopes exhibited significantly higher levels of trefoil, a third order aberration, in the amblyopic eye for both corneal and total ocular aberrations. The results of this experiment suggest that asymmetric visual experience during development is associated with asymmetries in higher-order aberrations, proportional to the magnitude of anisometropia and dependent upon the amblyogenic factor. This suggests a direct link between the development of higher-order optical characteristics of the human eye and visual feedback. The results from these experiments have shown that a high degree of symmetry exists between the fellow eyes of non-amblyopic myopic anisometropes for a range of biomechanical, biometric and optical parameters for different levels of accommodation and following near work. While a single specific optical or biomechanical factor that is consistently associated with asymmetric refractive error development has not been identified, the findings from these studies suggest that further research into the association between ocular dominance, choroidal thickness and higher-order aberrations with anisometropia may improve our understanding of refractive error development.

Lean supply chain performance evaluation method

Increasing global competitiveness worldwide has forced manufacturing organizations to produce high-quality products more quickly and at a competitive cost which demand of continuous improvements techniques. In this paper, we propose a fuzzy based performance evaluation method for lean supply chain. To understand the overall performance of cost competitive supply chain, we investigate the alignment of market strategy and position of the supply chain. Competitive strategies can be achieved by using a different weight calculation for different supply chain situations. By identifying optimal performance metrics and applying performance evaluation methods, managers can predict the overall supply chain performance under lean strategy.

Career path of a corruption entrepreneur

The study of criminal career paths is necessary to understand the methods of success employed by high-performing criminals. The aim of this article is to focus on the career path of Jack Herbert who set up and maintained extensive corruption networks between organised crime groups and police in the Australian state of Queensland. This study builds on Morselli’s work on the career paths of Sammy Gravano and Howard Marks that demonstrate how understanding social networks is an essential part of comprehending how organised criminals succeed. The data for this study were taken from the transcripts of the Fitzgerald Commission of Inquiry, which uncovered the extensive and resilient corruption network operated by Herbert. Herbert’s relationships have been plotted to establish the nature of his operations. The findings indicate that communication of trust both allows for success and sets the boundaries of a network. Most importantly, this case study identifies Herbert’s reliance on holding a monopoly as the cornerstone of his network power and position. This article adds to the literature on criminal career paths by moving away from a classic organised criminal grouping into the area of police corruption and uncovers the distinctive opportunities that this position offers the career criminal.

Examining the effects of an eco-driving message on driver distraction

This paper examines the effects of an eco-driving message on driver distraction. Two in-vehicle distracter tasks were compared with an eco-driving task and a baseline task in an advanced driving simulator. N = 22 subjects were asked to perform an eco-driving, CD changing, and a navigation task while engaged in critical manoeuvres during which they were expected to respond to a peripheral detection task (PDT) with total duration of 3.5 h. The study involved two sessions over two consecutive days. The results show that drivers’ mental workloads are significantly higher during navigation and CD changing tasks in comparison to the two other scenarios. However, eco-driving mental workload is still marginally significant (p ∼ .05) across different manoeuvres. Similarly, event detection tasks show that drivers miss significantly more events in the navigation and CD changing scenarios in comparison to both the baseline and eco-driving scenario. Analysis of the practice effect shows that drivers’ baseline scenario and navigation scenario exhibit significantly less demand on the second day. Drivers also can detect significantly more events on the second day for all scenarios. The authors conclude that even reading a simple message while driving could potentially lead to missing an important event, especially when executing critical manoeuvres. However, there is some evidence of a practice effect which suggests that future research should focus on performance with habitual rather than novel tasks. It is recommended that sending text as an eco-driving message analogous to the study circumstances should not be delivered to drivers on-line when vehicle is in motion.

Maintaining a cognitive map in darkness : the need to fuse boundary knowledge with path integration

Spatial navigation requires the processing of complex, disparate and often ambiguous sensory data. The neurocomputations underpinning this vital ability remain poorly understood. Controversy remains as to whether multimodal sensory information must be combined into a unified representation, consistent with Tolman's "cognitive map", or whether differential activation of independent navigation modules suffice to explain observed navigation behaviour. Here we demonstrate that key neural correlates of spatial navigation in darkness cannot be explained if the path integration system acted independently of boundary (landmark) information. In vivo recordings demonstrate that the rodent head direction (HD) system becomes unstable within three minutes without vision. In contrast, rodents maintain stable place fields and grid fields for over half an hour without vision. Using a simple HD error model, we show analytically that idiothetic path integration (iPI) alone cannot be used to maintain any stable place representation beyond two to three minutes. We then use a measure of place stability based on information theoretic principles to prove that featureless boundaries alone cannot be used to improve localization above chance level. Having shown that neither iPI nor boundaries alone are sufficient, we then address the question of whether their combination is sufficient and - we conjecture - necessary to maintain place stability for prolonged periods without vision. We addressed this question in simulations and robot experiments using a navigation model comprising of a particle filter and boundary map. The model replicates published experimental results on place field and grid field stability without vision, and makes testable predictions including place field splitting and grid field rescaling if the true arena geometry differs from the acquired boundary map. We discuss our findings in light of current theories of animal navigation and neuronal computation, and elaborate on their implications and significance for the design, analysis and interpretation of experiments.

Evaluation of the quality of diverse teaching practice in higher education research methods

The purpose of this paper is to report on a methods research project investigating the evaluation of diverse teaching practice in Higher Education. The research method is a single site case study of an Australian university with data collected through published documents, surveys, interviews and focus groups. This project provides evidence of the wide variety of evaluation practice and diverse teaching practice across the university. This breadth identifies the need for greater flexibility of evaluation processes, tools and support to assist teaching staff to evaluate their diverse teaching practice. The employment opportunities for academics benchmark the university nationally and position the case study in the field. Finally this reaffirms the institutional responsibility for services to support teaching staff in an ongoing manner.

Analysis of Cone-Beam CT using prior information

Treatment plans for conformal radiotherapy are based on an initial CT scan. The aim is to deliver the prescribed dose to the tumour, while minimising exposure to nearby organs. Recent advances make it possible to also obtain a Cone-Beam CT (CBCT) scan, once the patient has been positioned for treatment. A statistical model will be developed to compare these CBCT scans with the initial CT scan. Changes in the size, shape and position of the tumour and organs will be detected and quantified. Some progress has already been made in segmentation of prostate CBCT scans [1],[2],[3]. However, none of the existing approaches have taken full advantage of the prior information that is available. The planning CT scan is expertly annotated with contours of the tumour and nearby sensitive objects. This data is specific to the individual patient and can be viewed as a snapshot of spatial information at a point in time. There is an abundance of studies in the radiotherapy literature that describe the amount of variation in the relevant organs between treatments. The findings from these studies can form a basis for estimating the degree of uncertainty. All of this information can be incorporated as an informative prior into a Bayesian statistical model. This model will be developed using scans of CT phantoms, which are objects with known geometry. Thus, the accuracy of the model can be evaluated objectively. This will also enable comparison between alternative models.

Using natural user interfaces for collaborative process modelling in virtual environments

Modelling business processes for analysis or redesign usually requires the collaboration of many stakeholders. These stakeholders may be spread across locations or even companies, making co-located collaboration costly and difficult to organize. Modern process modelling technologies support remote collaboration but lack support for visual cues used in co-located collaboration. Previously we presented a prototype 3D virtual world process modelling tool that supports a number of visual cues to facilitate remote collaborative process model creation and validation. However, the added complexity of having to navigate a virtual environment and using an avatar for communication made the tool difficult to use for novice users. We now present an evolved version of the technology that addresses these issues by providing natural user interfaces for non-verbal communication, navigation and model manipulation.

Segmentation of cone-beam CT using a hidden Markov random field with informative priors

Purpose: Flat-detector, cone-beam computed tomography (CBCT) has enormous potential to improve the accuracy of treatment delivery in image-guided radiotherapy (IGRT). To assist radiotherapists in interpreting these images, we use a Bayesian statistical model to label each voxel according to its tissue type. Methods: The rich sources of prior information in IGRT are incorporated into a hidden Markov random field (MRF) model of the 3D image lattice. Tissue densities in the reference CT scan are estimated using inverse regression and then rescaled to approximate the corresponding CBCT intensity values. The treatment planning contours are combined with published studies of physiological variability to produce a spatial prior distribution for changes in the size, shape and position of the tumour volume and organs at risk (OAR). The voxel labels are estimated using the iterated conditional modes (ICM) algorithm. Results: The accuracy of the method has been evaluated using 27 CBCT scans of an electron density phantom (CIRS, Inc. model 062). The mean voxel-wise misclassification rate was 6.2%, with Dice similarity coefficient of 0.73 for liver, muscle, breast and adipose tissue. Conclusions: By incorporating prior information, we are able to successfully segment CBCT images. This could be a viable approach for automated, online image analysis in radiotherapy.

Segmentation of cone-beam CT using a hidden Markov random field with informative priors

Cone-beam computed tomography (CBCT) has enormous potential to improve the accuracy of treatment delivery in image-guided radiotherapy (IGRT). To assist radiotherapists in interpreting these images, we use a Bayesian statistical model to label each voxel according to its tissue type. The rich sources of prior information in IGRT are incorporated into a hidden Markov random field model of the 3D image lattice. Tissue densities in the reference CT scan are estimated using inverse regression and then rescaled to approximate the corresponding CBCT intensity values. The treatment planning contours are combined with published studies of physiological variability to produce a spatial prior distribution for changes in the size, shape and position of the tumour volume and organs at risk. The voxel labels are estimated using iterated conditional modes. The accuracy of the method has been evaluated using 27 CBCT scans of an electron density phantom. The mean voxel-wise misclassification rate was 6.2\%, with Dice similarity coefficient of 0.73 for liver, muscle, breast and adipose tissue. By incorporating prior information, we are able to successfully segment CBCT images. This could be a viable approach for automated, online image analysis in radiotherapy.

Experiments with cooperative control of underwater robots

In this paper we describe cooperative control algorithms for robots and sensor nodes in an underwater environment. Cooperative navigation is defined as the ability of a coupled system of autonomous robots to pool their resources to achieve long-distance navigation and a larger controllability space. Other types of useful cooperation in underwater environments include: exchange of information such as data download and retasking; cooperative localization and tracking; and physical connection (docking) for tasks such as deployment of underwater sensor networks, collection of nodes and rescue of damaged robots. We present experimental results obtained with an underwater system that consists of two very different robots and a number of sensor network modules. We present the hardware and software architecture of this underwater system. We then describe various interactions between the robots and sensor nodes and between the two robots, including cooperative navigation. Finally, we describe our experiments with this underwater system and present data.

Building distributed leadership for effective supervision of creative practice higher research degrees : final report 2014

Building distributed leadership for effective supervision of creative practice higher research degrees is an Office for Learning and Teaching (OLT) funded project, conducted in partnership between Queensland University of Technology, The University of Melbourne, Auckland University of Technology, University of New South Wales and University of Western Sydney. The project was initiated to develop a cooperative approach to establishing an understanding of the contextual frameworks of the emergent field of creative practice higher degrees by research (HDRs); capturing early insights of administrators and supervisors; gathering exemplars of good practices; and establishing an in-common understanding of effective approaches to supervision. To this end, the project has produced: • A literature review, to provide a research foundation for creative practice higher research degree supervision (Chapter 3). • A contextual review of disciplinary frameworks for HDR programs, produced through surveys of postgraduate research administrators (Section 4.1), and an analysis of institutional materials and academic development programs for supervisors (Section 4.2). • A National Symposium, Effective Supervision of Creative Arts Research Degrees (ESCARD), at QUT in Brisbane in February 2013, with 62 delegates from 20 Australasian Universities, at which project findings were disseminated, and delegates presented case studies and position papers, and participated in discussions on key issues for supervisors (Appendix 1). • Resources, including a booklet for supervisors: 12 Principles for the Effective Supervision of Creative Practice Higher Research Degrees, which encapsulates attitudes, insights and good practices of experienced and new supervisors. It was produced through a content analysis of interviews with twenty-five supervisors in creative disciplines (visual and performing arts, music, new media, creative writing and design) (Printed booklet, PDF, Appendix 3). • A project website to disseminate project outcomes , which holds project findings, relevant references, and a repository of case studies and position papers by supervisors and program administrators. • A call for papers for a special issue ‘Supervising Practice: Perspectives on the Supervision of Creative Practice Research Higher Degrees’ of ACCESS Journal: Critical Perspectives on Communication, Cultural & Policy Studies (ERA ranked A quality) in 2014 (Appendix 2). • A community of supervisory practice initiated through project partnerships, a national symposium where supervisors from across Australasia met in dialogue for the first time, resource sharing, and joint publishing opportunities. • A set of recommendations for supervision capacity building and academic development, produced through the triangulation of literature and contextual reviews, analysis of institutional frameworks, interviews with supervisors and national dialogues. It is anticipated that the project’s outcomes will support experienced and new supervisors in this emergent field, and so benefit HDR students, and will enable creative disciplines to build supervision capacity, and so to accommodate growth in postgraduate enrolments. Funded as a pilot project, the project set out to establish a robust research base to provide a foundation for future work involving sharing good practices, resource building, and designing effective approaches to academic development for supervisors. Recommendations that were produced out of this project include the need to extend beyond generic, formal training for supervisors to academic development that harnesses and extends distributed leadership; focuses on local, disciplinary contexts; has a strong emphasis on case studies; provides diverse resources; and facilitates dialogue between supervisors. Recommendations also include developing frameworks for mentoring new supervisors and building a national network to facilitate cross-institutional discourse, disseminate good practices, and share insights into the management of risk factors, ethical issues, and preparing candidates for examination. As a pilot investigation, the outcomes of this project lay the ground for this future work.

Living in a broken world : how young children's well-being is supported through playing out their earthquake experiences

The therapeutic value of play can be shown in spontaneous play situations following children’s experiences of traumatic events. Following the events of the Christchurch earthquakes in New Zealand in 2010 and 2011, an investigation was conducted of how children used the earthquake event as a catalyst in pretend play with peers and in discussions with teachers. Supporting children’s well-being is a focus area in New Zealand early childhood education as it is a strand of the national curriculum, Te Whāriki (Ministry of Education [MoE], 1996). In this article, children are observed engaging in pretend play episodes and with Learning Story books to explore personal reflections of the earthquake, prompting the children to make reference to things being ‘broken’ and needing 'fixing.' Analysis shows how the content of the pretend play experiences helped the children to come to terms with their experiences. Affording children time and interactional opportunities to play out and discuss traumatic experiences contributes to the psychological well-being of participants following a traumatic event.

False-colour spectrograms of long duration acoustic recordings

Acoustic recordings of the environment are an important aid to ecologists monitoring biodiversity and environmental health. However, rapid advances in recording technology, storage and computing make it possible to accumulate thousands of hours of recordings, of which, ecologists can only listen to a small fraction. The big-data challenge is to visualize the content of long-duration audio recordings on multiple scales, from hours, days, months to years. The visualization should facilitate navigation and yield ecologically meaningful information. Our approach is to extract (at one minute resolution) acoustic indices which reflect content of ecological interest. An acoustic index is a statistic that summarizes some aspect of the distribution of acoustic energy in a recording. We combine indices to produce false-colour images that reveal acoustic content and facilitate navigation through recordings that are months or even years in duration.

Selection et controle de modes de deplacement pour un robot mobile autonome en environnements naturels

Autonomous navigation and locomotion of a mobile robot in natural environments remain a rather open issue. Several functionalities are required to complete the usual perception/decision/action cycle. They can be divided in two main categories : navigation (perception and decision about the movement) and locomotion (movement execution). In order to be able to face the large range of possible situations in natural environments, it is essential to make use of various kinds of complementary functionalities, defining various navigation and locomotion modes. Indeed, a number of navigation and locomotion approaches have been proposed in the literature for the last years, but none can pretend being able to achieve autonomous navigation and locomotion in every situation. Thus, it seems relevant to endow an outdoor mobile robot with several complementary navigation and locomotion modes. Accordingly, the robot must also have means to select the most appropriate mode to apply. This thesis proposes the development of such a navigation/locomotion mode selection system, based on two types of data: an observation of the context to determine in what kind of situation the robot has to achieve its movement and an evaluation of the behavior of the current mode, made by monitors which influence the transitions towards other modes when the behavior of the current one is considered as non satisfying. Hence, this document introduces a probabilistic framework for the estimation of the mode to be applied, some navigation and locomotion modes used, a qualitative terrain representation method (based on the evaluation of a difficulty computed from the placement of the robot's structure on a digital elevation map), and monitors that check the behavior of the modes used (evaluation of rolling locomotion efficiency, robot's attitude and configuration watching. . .). Some experimental results obtained with those elements integrated on board two different outdoor robots are presented and discussed.