Robust design and optimisation of a radial turbine within a supercritical CO2 solar Brayton Cycle

The generation of solar thermal power is dependent upon the amount of sunlight exposure,as influenced by the day-night cycle and seasonal variations. In this paper, robust optimisation is applied to the design of a power block and turbine, which is generating 30 MWe from a concentrated solar resource of 560oC. The robust approach is important to attain a high average performance (minimum efficiency change) over the expected operating ranges of temperature, speed and mass flow. The final objective function combines the turbine performance and efficiency weighted by the off-design performance. The resulting robust optimisation methodology as presented in the paper gives further information that greatly aids in the design of non-classical power blocks through considering off-design conditions and resultant performance.

Improving PLDA speaker verification using WMFD and linear-weighted approaches in limited microphone data conditions

This paper proposes the addition of a weighted median Fisher discriminator (WMFD) projection prior to length-normalised Gaussian probabilistic linear discriminant analysis (GPLDA) modelling in order to compensate the additional session variation. In limited microphone data conditions, a linear-weighted approach is introduced to increase the influence of microphone speech dataset. The linear-weighted WMFD-projected GPLDA system shows improvements in EER and DCF values over the pooled LDA- and WMFD-projected GPLDA systems in inter-view-interview condition as WMFD projection extracts more speaker discriminant information with limited number of sessions/ speaker data, and linear-weighted GPLDA approach estimates reliable model parameters with limited microphone data.

Automatic clustering of white matter fibers in brain diffusion mri with an application to genetics

To understand factors that affect brain connectivity and integrity, it is beneficial to automatically cluster white matter (WM) fibers into anatomically recognizable tracts. Whole brain tractography, based on diffusion-weighted MRI, generates vast sets of fibers throughout the brain; clustering them into consistent and recognizable bundles can be difficult as there are wide individual variations in the trajectory and shape of WM pathways. Here we introduce a novel automated tract clustering algorithm based on label fusion - a concept from traditional intensity-based segmentation. Streamline tractography generates many incorrect fibers, so our top-down approach extracts tracts consistent with known anatomy, by mapping multiple hand-labeled atlases into a new dataset. We fuse clustering results from different atlases, using a mean distance fusion scheme. We reliably extracted the major tracts from 105-gradient high angular resolution diffusion images (HARDI) of 198 young normal twins. To compute population statistics, we use a pointwise correspondence method to match, compare, and average WM tracts across subjects. We illustrate our method in a genetic study of white matter tract heritability in twins.

Ergonomic assessment of hospital bed moving using DHM Siemens JACK

While the indirect and direct cost of occupational musculoskeletal disorders (MSD) causes a significant burden on the health system, lower back pain (LBP) is associated with a significant portion of MSD. In Australia, the highest prevalence of MSD exists for health care workers, such as nurses. The digital human model (DHM) Siemens JACK was used to investigate if hospital bed pushing, a simple task and hazard that is commonly associated with LBP, can be simulated and ergonomically assessed in a virtual environment. It was found that while JACK has implemented a range of common physical work assessment methods, the simulation of dynamic bed pushing remains a challenge due to the complex interface between the floor and wheels, which can only be insufficiently modelle

Do repeated rumble strip hits improve driver alertness?

Driving while sleepy is associated with increased crash risk. Rumble strips are designed to alert a sleepy or inattentive driver when they deviate outside their driving lane. The current study sought to examine the effects of repeated rumble strip hits on levels of physiological and subjective sleepiness as well as simulated driving performance. In total, 36 regular shift workers drove a high-fidelity moving base simulator on a simulated road with rumble strips installed at the shoulder and centre line after a working a full night shift. The results show that on average, the first rumble strip occurred after 20 minutes of driving, with subsequent hits occurring 10 minutes later, with the last three occurring approximately every 5 minutes thereafter. Specifically, it was found that the first rumble strip hit reduced physiological sleepiness; however, subsequent hits did not increase alertness. Moreover, the results also demonstrate that increased subjective sleepiness levels, via the Karolinska Sleepiness Scale, were associated with a greater probability of hitting a rumble strip. The present results suggest that sleepiness is very resilient to even strongly arousing stimuli, with physiologicl and subjective sleepiness increasing over the duration of the drive, despite the interference by rumble strips.

Disciplining the screen through education: The Royal Commission into the moving picture industry in Australia

In this article, we investigate the complex relationship between concerns about children and young people’s exposure to cinema in 1920s Australia and the use of film in education. In part, the Royal Commission into the Moving Picture Industry in Australia aimed to ‘ascertain the effect and the extent of the power of film upon juveniles’ and Commissioners spoke to educationalists, psychologists, medical professions, police officers and parents to gain insight into the impacts of movies on children. Numerous issues were canvassed in the Commission hearings such as exposure to sexual content, ‘excesses’ in film content, children’s inability to concentrate at school following cinema attendance and the influence of cinema on youth crime. While the Commission ultimately suggested it was parents’ role to police children’s engagements with cinema, it did make recommendations for restricting children’s access to films with inappropriate themes. Meanwhile, the Commission was very positive about film’s educational role stating that ‘the advantage to be gained by the use of the cinematograph as an adjunct to educational methods should be assisted in every possible way by the Commonwealth’. We draw on the Commission’s minutes of evidence, the Commission report and newspaper articles form the 1920s to the 1940s to argue that the Commission provides valuable insight into the beginnings of the use of screen content in formal schooling, both as a resource across the curriculum and as a specific focus of education through film appreciation and, later, broader forms of media education. The article argues debates about screen entertainment and education rehearsed in the Commission are reflected today as parents, concerned citizens and educators ponder the dangers and potential of new media technologies and media content used by children and young people such as video games, social media and interactive content.

The vertebral venous system in healthy and scoliotic adolescent spines - a 3D MRI investigation

Introduction. The venous drainage system within vertebral bodies (VBs) has been well documented previously in cadaveric specimens. Advances in 3D imaging and image processing now allow for in vivo quantification of larger venous vessels, such as the basivertebral vein. Differences between healthy and scoliotic VB veins can therefore be investigated. Methods. 20 healthy adolescent controls and 21 AIS patients were recruited (with ethics approval) to undergo 3D MRI, using a 3 Tesla, T1-weighted 3D gradient echo sequence, resulting in 512 slices across the thoraco-lumbar spine, with a voxel size of 0.5x0.5x0.5mm. Using Amira Filament Editor, five transverse slices through the VB were examined simultaneously and the resulting observable vascular network traced. Each VB was assessed, and a vascular network recorded when observable. A local coordinate system was created in the centre of each VB and the vascular networks aligned to this. The length of the vascular network on the left and right sides (with a small central region) of the VB was calculated, and the spatial patterning of the networks assessed level-by-level within each subject. Results. An average of 6 (range 4-10) vascular networks, consistent with descriptions of the basivertebral vein, were identifiable within each subject, most commonly between T10-L1. Differences were seen in the left/right distribution of vessels in the control and AIS subjects. Healthy controls saw a percentage distribution of 29:18:53 across the left:centre:right regions respectively, whereas the AIS subjects had a slightly shifted distribution of 33:25:42. The control group showed consistent spatial patterning of the vascular networks across most levels, but this was not seen in the AIS group. Conclusion. Observation and quantification of the basivertebral vein in vivo is possible using 3D MRI. The AIS group lacked the spatial pattern repetition seen in the control group and minor differences were seen in the left/right distribution of vessels.

Moving from evaluation to trial: The case of cloud ERP adoption in SMEs

This study proposes that the adoption process of complex-wide systems (e.g. cloud ERP) should be observed as multi-stage actions. Two theoretical lenses were utilised for this study with critical adoption factors identified through the theory of planned behaviour and the progression of each adoption factor observed through Ettlie's (1980) multi-stage adoption model. Together with a survey method, this study has employed data gathered from 162 decision-makers of small and medium-sized enterprises (SMEs). Using both linear and non-linear approaches for the data analysis, the study findings have shown that the level of importance for adoption factors changes across different adoption stages.

Functional localization of the human color center by decreased water displacement using diffusion-weighted fMRI

Introduction Decreased water displacement following increased neural activity has been observed using diffusion-weighted functional MRI (DfMRI) at high b-values. The physiological mechanisms underlying the diffusion signal change may be unique from the standard blood oxygenation level-dependent (BOLD) contrast and closer to the source of neural activity. Whether DfMRI reflects neural activity more directly than BOLD outside the primary cerebral regions remains unclear. Methods Colored and achromatic Mondrian visual stimuli were statistically contrasted to functionally localize the human color center Area V4 in neurologically intact adults. Spatial and temporal properties of DfMRI and BOLD activation were examined across regions of the visual cortex. Results At the individual level, DfMRI activation patterns showed greater spatial specificity to V4 than BOLD. The BOLD activation patterns were more prominent in the primary visual cortex than DfMRI, where activation was localized to the ventral temporal lobe. Temporally, the diffusion signal change in V4 and V1 both preceded the corresponding hemodynamic response, however the early diffusion signal change was more evident in V1. Conclusions DfMRI may be of use in imaging applications implementing cognitive subtraction paradigms, and where highly precise individual functional localization is required.

Acoustic features for multi-level classification of Australian frogs

Over past few decades, frog species have been experiencing dramatic decline around the world. The reason for this decline includes habitat loss, invasive species, climate change and so on. To better know the status of frog species, classifying frogs has become increasingly important. In this study, acoustic features are investigated for multi-level classification of Australian frogs: family, genus and species, including three families, eleven genera and eighty five species which are collected from Queensland, Australia. For each frog species, six instances are selected from which ten acoustic features are calculated. Then, the multicollinearity between ten features are studied for selecting non-correlated features for subsequent analysis. A decision tree (DT) classifier is used to visually and explicitly determine which acoustic features are relatively important for classifying family, which for genus, and which for species. Finally, a weighted support vector machines (SVMs) classifier is used for the multi- level classification with three most important acoustic features respectively. Our experiment results indicate that using different acoustic feature sets can successfully classify frogs at different levels and the average classification accuracy can be up to 85.6%, 86.1% and 56.2% for family, genus and species respectively.

Moving on (part 2): Power and the child in curriculum history

This paper is the second in a two-part series that maps continuities and ruptures in conceptions of power and traces their effects in educational discourse on 'the child'. It delineates two post-Newtonian intellectual trajectories through which concepts of 'power' arrived at the theorization of 'the child': the paradoxical bio-physical inscriptions of human-ness that accompanied mechanistic worldviews and the explanations for social motion in political philosophy. The intersection of pedagogical theories with 'the child' and 'power' is further traced from the latter 1800s to the present, where a Foucaultian analytics of power-as-effects is reconsidered in regard to histories of motion. The analysis culminates in an examination of post-Newtonian (dis)continuities in the theorization of power, suggesting some productive paradoxes that inhabit turn of the 21st-century conceptualizations of the social.

Moving on (part 1): The physics of power and curriculum history

This is the first of two papers that map (dis)continuities in notions of power from Aristotle to Newton to Foucault. They trace the ways in which bio-physical conceptions of power became paraphrased in social science and deployed in educational discourse on the child and curriculum from post-Newtonian times to the present. The analyses suggest that, amid ruptures in the definition, role, location and meaning given 'power' historically in various 'physical' and 'social' cosmologies, the naming of 'power' has been dependent on 'physics', on the theorization of motion across 'Western' sciences. This first paper examines some (dis)continuities in regard to histories of motion and power from Aristotelian 'natural science' to Newtonian mechanics.

Making apartments affordable: Moving from speculative to deliberative development

Urban planning policies in Australia presuppose apartments as the new dominant housing type, but much of what the market has delivered is criticised as over-development, and as being generic, poorly-designed, environmentally unsustainable and unaffordable. Policy responses to this problem typically focus on planning regulation and construction costs as the primary issues needing to be addressed in order to increase the supply of quality, affordable apartment housing. In contrast, this paper uses Ball’s (1983) ‘structures of provision’ approach to outline the key processes informing apartment development and identifies a substantial gap in critical understanding of how apartments are developed in Australia. This reveals economic problems not typically considered by policymakers. Using mainstream economic analysis to review the market itself, the authors found high search costs, demand risk, problems with exchange, and lack of competition present key barriers to achieving greater affordability and limit the extent to which ‘speculative’ developers can respond to the preferences of would be owner-occupiers of apartments. The existing development model, which is reliant on capturing uplift in site value, suits investors seeking rental yields in the first instance and capital gains in the second instance, and actively encourages housing price inflation. This is exacerbated by lack of density restrictions, such as have existed in inner Melbourne for many years, which permits greater yields on redevelopment sites. The price of land in the vicinity of such redevelopment sites is pushed up as landholders' expectation of future yield is raised. All too frequently existing redevelopment sites go back onto the market as vendors seek to capture the uplift in site value and exit the project in a risk free manner...

A three-dimensional hybrid smoothed finite element method (H-SFEM) for nonlinear solid mechanics problems

This paper presents a novel three-dimensional hybrid smoothed finite element method (H-SFEM) for solid mechanics problems. In 3D H-SFEM, the strain field is assumed to be the weighted average between compatible strains from the finite element method (FEM) and smoothed strains from the node-based smoothed FEM with a parameter α equipped into H-SFEM. By adjusting α, the upper and lower bound solutions in the strain energy norm and eigenfrequencies can always be obtained. The optimized α value in 3D H-SFEM using a tetrahedron mesh possesses a close-to-exact stiffness of the continuous system, and produces ultra-accurate solutions in terms of displacement, strain energy and eigenfrequencies in the linear and nonlinear problems. The novel domain-based selective scheme is proposed leading to a combined selective H-SFEM model that is immune from volumetric locking and hence works well for nearly incompressible materials. The proposed 3D H-SFEM is an innovative and unique numerical method with its distinct features, which has great potential in the successful application for solid mechanics problems.

Weighted rank regression for clustered data analysis

We consider ranked-based regression models for clustered data analysis. A weighted Wilcoxon rank method is proposed to take account of within-cluster correlations and varying cluster sizes. The asymptotic normality of the resulting estimators is established. A method to estimate covariance of the estimators is also given, which can bypass estimation of the density function. Simulation studies are carried out to compare different estimators for a number of scenarios on the correlation structure, presence/absence of outliers and different correlation values. The proposed methods appear to perform well, in particular, the one incorporating the correlation in the weighting achieves the highest efficiency and robustness against misspecification of correlation structure and outliers. A real example is provided for illustration.