Influence of spherical intraocular lens implantation and conventional laser in situ keratomileusis on peripheral ocular aberrations

Aim: To measure the influence of spherical intraocular lens implantation and conventional myopic laser in situ keratomileusis on peripheral ocular aberrations. Setting: Visual & Ophthalmic Optics Laboratory, School of Optometry & Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia. Methods: Peripheral aberrations were measured using a modified commercial Hartmann-Shack aberrometer across 42° x 32° of the central visual field in 6 subjects after spherical intraocular lens (IOL) implantation and in 6 subjects after conventional laser in situ keratomileusis (LASIK) for myopia. The results were compared with those of age matched emmetropic and myopic control groups. Results: The IOL group showed a greater rate of quadratic change of spherical equivalent refraction across the visual field, higher spherical aberration, and greater rates of change of higher-order root-mean-square aberrations and total root-mean-square aberrations across the visual field than its emmetropic control group. However, coma trends were similar for the two groups. The LASIK group had a greater rate of quadratic change of spherical equivalent refraction across the visual field, higher spherical aberration, the opposite trend in coma across the field, and greater higher-order root-mean-square aberrations and total root-mean-square aberrations than its myopic control group. Conclusion: Spherical IOL implantation and conventional myopia LASIK increase ocular peripheral aberrations. They cause considerable increase in spherical aberration across the visual field. LASIK reverses the sign of the rate of change in coma across the field relative to that of the other groups. Keywords: refractive surgery, LASIK, IOL implantation, aberrations, peripheral aberrations

Reactive navigation and opportunistic localization for autonomous underground mining vehicles

This paper describes an autonomous navigation system for a large underground mining vehicle. The control architecture is based on a robust reactive wall-following behaviour. To make it purposeful we provide driving hints derived from an approximate nodal-map. For most of the time, the vehicle is driven with weak localization (odometry). This need only be improved at intersections where decisions must be made – a technique we refer to as opportunistic localization. The paper briefly reviews absolute and relative navigation strategies, and describes an implementation of a reactive navigation system on a 30 tonne Load-Haul-Dump truck. This truck has achieved full-speed autonomous operation at an artificial test mine, and subsequently, at a operational underground mine.

The impact of outcomes-driven curriculum reform on teacher perspectives of professional practice

This thesis is the result of an investigation of a Queensland example of curriculum reform based on outcomes, a type of reform common to many parts of the world during the last decade. The purpose of the investigation was to determine the impact of outcomes on teacher perspectives of professional practice. The focus was chosen to permit investigation not only of changes in behaviour resulting from the reform but also of teachers' attitudes and beliefs developed during implementation. The study is based on qualitative methodology, chosen because of its suitability for the investigation of attitudes and perspectives. The study exploits the researcher's opportunities for prolonged, direct contact with groups of teachers through the selection of an over-arching ethnography approach, an approach designed to capture the holistic nature of the reform and to contextualise the data within a broad perspective. The selection of grounded theory as a basis for data analysis reflects the open nature of this inquiry and demonstrates the study's constructivist assumptions about the production of knowledge. The study also constitutes a multi-site case study by virtue of the choice of three individual school sites as objects to be studied and to form the basis of the report. Three primary school sites administered by Brisbane Catholic Education were chosen as the focus of data collection. Data were collected from three school sites as teachers engaged in the first year of implementation of Student Performance Standards, the Queensland version of English outcomes based on the current English syllabus. Teachers' experience of outcomes-driven curriculum reform was studied by means of group interviews conducted at individual school sites over a period of fourteen months, researcher observations and the collection of artefacts such as report cards. Analysis of data followed grounded theory guidelines based on a system of coding. Though classification systems were not generated prior to data analysis, the labelling of categories called on standard, non-idiosyncratic terminology and analytic frames and concepts from existing literature wherever practicable in order to permit possible comparisons with other related research. Data from school sites were examined individually and then combined to determine teacher understandings of the reform, changes that have been made to practice and teacher responses to these changes in terms of their perspectives of professionalism. Teachers in the study understood the reform as primarily an accountability mechanism. Though teachers demonstrated some acceptance of the intentions of the reform, their responses to its conceptualisation, supporting documentation and implications for changing work practices were generally characterised by reduced confidence, anger and frustration. Though the impact of outcomes-based curriculum reform must be interpreted through the inter-relationships of a broad range of elements which comprise teachers' work and their attitudes towards their work, it is proposed that the substantive findings of the study can be understood in terms of four broad themes. First, when the conceptual design of outcomes did not serve teachers' accountability requirements and outcomes were perceived to be expressed in unfamiliar technical language, most teachers in the study lost faith in the value of the reform and lost confidence in their own abilities to understand or implement it. Second, this reduction of confidence was intensified when the scope of outcomes was outside the scope of the teachers' existing curriculum and assessment planning and teachers were confronted with the necessity to include aspects of syllabuses or school programs which they had previously omitted because of a lack of understanding or appreciation. The corollary was that outcomes promoted greater syllabus fidelity when frameworks were closely aligned. Third, other benefits the teachers associated with outcomes included the development of whole school curriculum resources and greater opportunity for teacher collaboration, particularly among schools. The teachers, however, considered a wide range of factors when determining the overall impact of the reform, and perceived a number of them in terms of the costs of implementation. These included the emergence of ethical dilemmas concerning relationships with students, colleagues and parents, reduced individual autonomy, particularly with regard to the selection of valued curriculum content and intensification of workload with the capacity to erode the relationships with students which teachers strongly associated with the rewards of their profession. Finally, in banding together at the school level to resist aspects of implementation, some teachers showed growing awareness of a collective authority capable of being exercised in response to top-down reform. These findings imply that Student Performance Standards require review and, additional implementation resourcing to support teachers through times of reduced confidence in their own abilities. Outcomes prove an effective means of high-fidelity syllabus implementation, and, provided they are expressed in an accessible way and aligned with syllabus frameworks and terminology, should be considered for inclusion in future syllabuses across a range of learning areas. The study also identifies a range of unintended consequences of outcomes-based curriculum and acknowledges the complexity of relationships among all the aspects of teachers' work. It also notes that the impact of reform on teacher perspectives of professional practice may alter teacher-teacher and school-system relationships in ways that have the potential to influence the effectiveness of future curriculum reform.

Aligning project stakeholder motivation through incentivisation : a client-driven approach

The use of appropriate financial incentives within construction projects can contribute to strong alignment of project stakeholder motivation with project goals. However, effective incentive system design can be a challenging task and takes skillful planning by client managers in the early stages of a project. In response to a lack of information currently available to construction clients in this area, this paper explores the features of a successful incentive system and identifies key learnings for client managers to consider when designing incentives. Our findings, based on data from a large Australian case study, suggest that key stakeholders place greater emphasis on the project management processes that support incentives than on the incentive itself. Further, contractors need adequate time and information to accurately estimate construction costs prior to their tender price submission to ensure cost-focused incentive goals remain achievable. Thus, client managers should be designing incentives as part of a supportive procurement strategy to maximize project stakeholder motivation and prevent goal misalignment.

Quantification of the relationship between Fuser Roller Temperature and Laser Printer Emissions

Recently published studies not only demonstrated that laser printers are often significant sources of ultrafine particles, but they also shed light on particle formation mechanisms. While the role of fuser roller temperature as a factor affecting particle formation rate has been postulated, its impact has never been quantified. To address this gap in knowledge, this study measured emissions from 30 laser printers in chamber using a standardized printing sequence, as well as monitoring fuser roller temperature. Based on a simplified mass balance equation, the average emission rates of particle number, PM2.5 and O3 were calculated. The results showed that: almost all printers were found to be high particle number emitters (i.e. > 1.01×1010 particles/min); colour printing generated more PM2.5 than monochrome printing; and all printers generated significant amounts of O3. Particle number emissions varied significantly during printing and followed the cycle of fuser roller temperature variation, which points to temperature being the strongest factor controlling emissions. For two sub-groups of printers using the same technology (heating lamps), systematic positive correlations, in the form of a power law, were found between average particle number emission rate and average roller temperature. Other factors, such as fuser material and structure, are also thought to play a role, since no such correlation was found for the remaining two sub-groups of printers using heating lamps, or for the printers using heating strips. In addition, O3 and total PM2.5 were not found to be statistically correlated with fuser temperature.

Standards-driven reform years 1-10 : moderation an optional extra?

While externally moderated standards-based assessment has been practised in Queensland senior schooling for more than three decades, there has been no such practice in the middle years. With the introduction of standards at state and national levels in these years, teacher judgement as developed in moderation practices is now vital. This paper argues, that in this context of assessment reform, standards intended to inform teacher judgement and to build assessment capacity are necessary but not sufficient for maintaining teacher and public confidence in schooling. Teacher judgement is intrinsic to moderation, and to professional practice, and can no longer remain private. Moderation too is intrinsic to efforts by the profession to realise judgements that are defensible, dependable and open to scrutiny. Moderation can no longer be considered an optional extra and requires system-level support especially if, as intended, the standards are linked to system-wide efforts to improve student learning. In presenting this argument we draw on an Australian Research Council funded study with key industry partners (the Queensland Studies Authority and the National Council for Curriculum and Assessment of the Republic of Ireland). The data analysed included teacher interview data and additional teacher talk during moderation sessions. These were undertaken during the initial phase of policy development. The analysis identified those issues that emerge in moderation meetings that are designed to reach consistent, reliable judgements. Of interest are the different ways in which teachers talked through and interacted with one another to reach agreement about the quality of student work in the application of standards. There is evidence of differences in the way that teachers made compensations and trade-offs in their award of grades, dependent on the subject domain in which they teach. This article concludes with some empirically derived insights into moderation practices as policy and social events.

New stress and velocity fields for highly frictional granular materials

The idealised theory for the quasi-static flow of granular materials which satisfy the Coulomb-Mohr hypothesis is considered. This theory arises in the limit that the angle of internal friction approaches $\pi/2$, and accordingly these materials may be referred to as being `highly frictional'. In this limit, the stress field for both two-dimensional and axially symmetric flows may be formulated in terms of a single nonlinear second order partial differential equation for the stress angle. To obtain an accompanying velocity field, a flow rule must be employed. Assuming the non-dilatant double-shearing flow rule, a further partial differential equation may be derived in each case, this time for the streamfunction. Using Lie symmetry methods, a complete set of group-invariant solutions is derived for both systems, and through this process new exact solutions are constructed. Only a limited number of exact solutions for gravity driven granular flows are known, so these results are potentially important in many practical applications. The problem of mass flow through a two-dimensional wedge hopper is examined as an illustration.

Lie group symmetry analysis for granular media stress equations

The Airy stress function, although frequently employed in classical linear elasticity, does not receive similar usage for granular media problems. For plane strain quasi-static deformations of a cohesionless Coulomb–Mohr granular solid, a single nonlinear partial differential equation is formulated for the Airy stress function by combining the equilibrium equations with the yield condition. This has certain advantages from the usual approach, in which two stress invariants and a stress angle are introduced, and a system of two partial differential equations is needed to describe the flow. In the present study, the symmetry analysis of differential equations is utilised for our single partial differential equation, and by computing an optimal system of one-dimensional Lie algebras, a complete set of group-invariant solutions is derived. By this it is meant that any group-invariant solution of the governing partial differential equation (provided it can be derived via the classical symmetries method) may be obtained as a member of this set by a suitable group transformation. For general values of the parameters (angle of internal friction and gravity g) it is found there are three distinct classes of solutions which correspond to granular flows considered previously in the literature. For the two limiting cases of high angle of internal friction and zero gravity, the governing partial differential equation admit larger families of Lie point symmetries, and from these symmetries, further solutions are derived, many of which are new. Furthermore, the majority of these solutions are exact, which is rare for granular flow, especially in the case of gravity driven flows.

Free surface problems for static Coulomb-Mohr granular solids

This paper is concerned with some plane strain and axially symmetric free surface problems which arise in the study of static granular solids that satisfy the Coulomb-Mohr yield condition. Such problems are inherently nonlinear, and hence difficult to attack analytically. Given a Coulomb friction condition holds on a solid boundary, it is shown that the angle a free surface is allowed to attach to the boundary is dependent only on the angle of wall friction, assuming the stresses are all continuous at the attachment point, and assuming also that the coefficient of cohesion is nonzero. As a model problem, the formation of stable cohesive arches in hoppers is considered. This undesirable phenomena is an obstacle to flow, and occurs when the hopper outlet is too small. Typically, engineers are concerned with predicting the critical outlet size for a given hopper and granular solid, so that for hoppers with outlets larger than this critical value, arching cannot occur. This is a topic of considerable practical interest, with most accepted engineering methods being conservative in nature. Here, the governing equations in two limiting cases (small cohesion and high angle of internal friction) are considered directly. No information on the critical outlet size is found; however solutions for the shape of the free boundary (the arch) are presented, for both plane and axially symmetric geometries.

Empirical basis for adopting a theory-driven approach to preventing alcohol and other drug impairment (AOD) in the workplace

Background: A State-based industry in Australia is in the process of developing a programme to prevent AOD impairment in the workplace. The objective of this study was to determine whether the Theory of Planned Behaviour can help explain the mechanisms by which behaviour change occurs with regard to AOD impairment in the workplace. ---------- Method: A survey of 1165 employees of a State-based industry in Australia was conducted, and a response rate of 98% was achieved. The survey included questions relevant to the Theory of Planned Behaviour: behaviour; behavioural intentions; attitude; perceptions of social pressure; and perceived behavioural control with regard to workplace AOD impairment. ---------- Findings: Less than 3% of participants reported coming to work impaired by AODs. Fewer than 2% of participants reported that they intended to come to work impaired by AODs. The majority of participants (over 80%) reported unfavourable attitudes toward AOD impairment at work. Logistic regression analyses suggest that, consistent with the theory of planned behaviour: attitudes, perceptions of social pressure, and perceived behavioural control with regard to workplace AOD impairment, all predict behavioural intentions (P < .001); and behavioural intentions predict (self-reported) behaviour regarding workplace AOD impairment (P < .001). ---------- Conclusions: The Theory of Planned Behaviour appears to assist with understanding the mechanisms by which behaviour change occurs with regard to AOD impairment in the workplace. An occupational AOD programme which targets those mechanisms for change may improve its impact in preventing workplace AOD impairment.

Values-driven leadership

The values of a leader set the culture of an organisation, determine the effectiveness of an organisation, and determine the success of an organisation. Understanding our values and being able to live our values adds significant emphasis to the leadership roles we perform in life. This book looks at where our values come from, and their role and impact in an organisational context. It offers a detailed conversation about values driven leadership - what it is and what it looks like.

User-driven saliency maps for evaluating Region-of-Interest detection

Detection of Region of Interest (ROI) in a video leads to more efficient utilization of bandwidth. This is because any ROIs in a given frame can be encoded in higher quality than the rest of that frame, with little or no degradation of quality from the perception of the viewers. Consequently, it is not necessary to uniformly encode the whole video in high quality. One approach to determine ROIs is to use saliency detectors to locate salient regions. This paper proposes a methodology for obtaining ground truth saliency maps to measure the effectiveness of ROI detection by considering the role of user experience during the labelling process of such maps. User perceptions can be captured and incorporated into the definition of salience in a particular video, taking advantage of human visual recall within a given context. Experiments with two state-of-the-art saliency detectors validate the effectiveness of this approach to validating visual saliency in video. This paper will provide the relevant datasets associated with the experiments.