Power electronic converters for high power ultrasound transducers

Piezoelectric transducers convert electrical energy to mechanical energy and play a great role in ultrasound systems. Ultrasound power transducer performance is strongly related to the applied electrical excitation. To have a suitable excitation for maximum energy conversion, it is required to analyze the effects of input signal waveform, medium and input signal distortion on the characteristic of a high power ultrasound system (including ultrasound transducer). In this research, different input voltage signals are generated using a single-phase power inverter and a linear power amplifier to excite a high power ultrasound transducer in different medium (water and oil) in order to study the characteristic of the system. We have also considered and analyzed the effect of power converter output voltage distortions on the performance of the high power ultrasound transducer using a passive filter.

Improving the efficiency of high power piezoelectric transducers for industrial applications

Most high-power ultrasound applications are driven by two-level inverters. However, the broad spectral content of the two-level pulse results in undesired harmonics that can decrease the performance of the system significantly. On the other hand, it is crucial to excite the piezoelectric devices at their main resonant frequency in order to have maximum energy conversion. Therefore a high-quality, low-distorted power signal is needed to excite the high-power piezoelectric transducer at its resonant frequency. This study proposes an efficient approach to develop the performance of high-power ultrasonic applications using multilevel inverters along with a frequency estimation algorithm. In this method, the resonant frequencies are estimated based on relative minimums of the piezoelectric impedance frequency response. The algorithm follows the resonant frequency variation and adapts the multilevel inverter reference frequency to drive an ultrasound transducer at high power. Extensive simulation and experimental results indicate the effectiveness of the proposed approach.

Solving inherent problems of anomaly detection by cooperation

Anomaly detection compensates shortcomings of signature-based detection such as protecting against Zero-Day exploits. However, Anomaly Detection can be resource-intensive and is plagued by a high false-positive rate. In this work, we address these problems by presenting a Cooperative Intrusion Detection approach for the AIS, the Artificial Immune System, as an example for an anomaly detection approach. In particular we show, how the cooperative approach reduces the false-positive rate of the detection and how the overall detection process can be organized to account for the resource constraints of the participating devices. Evaluations are carried out with the novel network simulation environment NeSSi as well as formally with an extension to the epidemic spread model SIR

Consequences of extensional tectonics on volcanic eruption style, compositions and source regions : new insights from the southern Sierra Madre Occidental and Gulf of California regions, western Mexico

Understanding the link between tectonic-driven extensional faulting and volcanism is crucial from a hazard perspective in active volcanic environments, while ancient volcanic successions provide records on how volcanic eruption styles, compositions, magnitudes and frequencies can change in response to extension timing, distribution and intensity. This study draws on intimate relationships of volcanism and extension preserved in the Sierra Madre Occidental (SMO) and Gulf of California (GoC) regions of western Mexico. Here, a major Oligocene rhyolitic ignimbrite “flare-up” (>300,000 km3) switched to a dominantly bimodal and mixed effusive-explosive volcanic phase in the Early Miocene (~100,000 km3), associated with distributed extension and opening of numerous grabens. Rhyolitic dome fields were emplaced along graben edges and at intersections of cross-graben and graben-parallel structures during early stages of graben development. Concomitant with this change in rhyolite eruption style was a change in crustal source as revealed by zircon chronochemistry with rapid rates of rhyolite magma generation due to remelting of mid- to upper crustal, highly differentiated igneous rocks emplaced during earlier SMO magmatism. Extension became more focused ~18 Ma resulting in volcanic activity being localised along the site of GoC opening. This localised volcanism (known as the Comondú “arc”) was dominantly effusive and andesite-dacite in composition. This compositional change resulted from increased mixing of basaltic and rhyolitic magmas rather than fluid flux melting of the mantle wedge above the subducting Guadalupe Plate. A poor understanding of space-time relationships of volcanism and extension has thus led to incorrect past tectonic interpretations of Comondú-age volcanism.

Principles of motor learning in ecological dynamics : a comment on functions of learning and the acquisition of motor skills (with reference to sport)

This paper provides a commentary on the contribution by Dr Chow who questioned whether the functions of learning are general across all categories of tasks or whether there are some task-particular aspects to the functions of learning in relation to task type. Specifically, they queried whether principles and practice for the acquisition of sport skills are different than what they are for musical, industrial, military and human factors skills. In this commentary we argue that ecological dynamics contains general principles of motor learning that can be instantiated in specific performance contexts to underpin learning design. In this proposal, we highlight the importance of conducting skill acquisition research in sport, rather than relying on empirical outcomes of research from a variety of different performance contexts. Here we discuss how task constraints of different performance contexts (sport, industry, military, music) provide different specific information sources that individuals use to couple their actions when performing and acquiring skills. We conclude by suggesting that his relationship between performance task constraints and learning processes might help explain the traditional emphasis on performance curves and performance outcomes to infer motor learning.

Coping resources, coping strategies and adaptation to organisational change : direct or buffering effects?

This study examined the effects of personal and social resources, coping strategies and appraised stress on employees' levels of anxiety and depression. In relation to the effects of resources and coping strategies, two different models were tested. The main effects model proposes that, irrespective of the level of stress, coping resources and coping strategies have direct effects on well-being. In contrast, the buffering model predicts that the buffering effects of coping resources and strategies are only evident at high levels of stress. One hundred lawyers completed a structured self-administered questionnaire that measured their personal and social resources, use of problem-focused and emotion-focused coping strategies, and appraisals of the stressfulness of the situation. Results revealed generally strong support for the main effects model in the prediction of employee levels of anxiety and depression. Lower levels of anxiety were linked to judgements of lower levels of organizational change, greater self-confidence, greater internality of control beliefs and less use of emotion-focused coping strategies. Lower levels of depression in employees were also linked to judgements of lower levels of organizational change, greater use of resources and less appraised stress. There was only limited support for the buffering effects model. Due to the small size of the sample, the findings need to be explored further in other contexts.

Prediction of multilocus identity-by-descent

Previous studies have enabled exact prediction of probabilities of identity-by-descent (IBD) in randommating populations for a few loci (up to four or so), with extension to more using approximate regression methods. Here we present a precise predictor of multiple-locus IBD using simple formulas based on exact results for two loci. In particular, the probability of non-IBD X ABC at each of ordered loci A, B, and C can be well approximated by XABC = XABXBC/XB and generalizes to X123. . .k = X12X23. . .Xk-1,k/ Xk-2, where X is the probability of non-IBD at each locus. Predictions from this chain rule are very precise with population bottlenecks and migration, but are rather poorer in the presence of mutation. From these coefficients, the probabilities of multilocus IBD and non-IBD can also be computed for genomic regions as functions of population size, time, and map distances. An approximate but simple recurrence formula is also developed, which generally is less accurate than the chain rule but is more robust with mutation. Used together with the chain rule it leads to explicit equations for non-IBD in a region. The results can be applied to detection of quantitative trait loci (QTL) by computing the probability of IBD at candidate loci in terms of identity-by-state at neighboring markers.

What relationships exist between general self efficacy, locus of control and the nursing practice environment and caring efficacy and job satisfaction?

Research Question: What relationships exist between general self efficacy, locus of control and the nursing practice environment and caring efficacy and job satisfaction? Background: Important characteristics of current nursing practice include nurses having the ability to develop and continue therapeutic relationships with patients, nurses having autonomy and control over the practice environment and nurses having more involvement in decision making. In addition, employee satisfaction is enhanced when organisations offer access to authority. Despite this, nurses continue to complain of feeling powerless in their ability to make decisions. Sample: The study population and criteria for selection included Registered Nurses in Australia who were at the time members of an Australian professional and industrial organisation. Methods: A cross-sectional survey was undertaken. Data analysis was conducted using descriptive and bivariate statistics, and structural equation modeling. Results: The model fit the data well (χ² = 2.3594, χ²/df = 2.3594 and CFI = 0.9987). Twenty four percent of variation in caring efficacy (CE) can be accounted for by general self-efficacy (GSE); work locus of control (WLC) and practice environment (PE) and 62% of the variation in job satisfaction (JS) can be accounted for by GSE, WLC and PE. All pathways were found to be significant except PE to CE. GSE positively explained CE (β = 0.38). WLC was negatively related to CE i.e., as CE scores increased WLC scores decreased (β = -0.23). Further testing of the model found CE was positively related to GSE (βZ = 0.38, p < 0.001) and negatively related to WLC (βZ = - 0.23, p = 0.001). PE was not significantly associated with CE (βZ = - 0.01, p = 0.85). JS was explained by PE, which was positively related (βZ = 0.69, p = < 0.001); GSE which was negatively related (βZ - 0 .09, p < 0.001) and WLC, which was also negatively related (βZ = - 0.20, p < 0.001). Implications for Practice Nursing and organisational leaders should ensure the development of strategies for professional development and orientation programmes which may enhance nurses’ ability to develop caring relationships and express caring behaviours to their patients and as a result improve organisational and patient outcomes. Nursing shortages and turnover rates are associated with job satisfaction and the nursing practice environment. Improving the nursing environment can produce benefits to the health system such as better job satisfaction, improved workforce retention and better patient outcomes.

Examination of factors affecting caring efficacy, job satisfaction in Australian registered nurses

Research Question: What relationships exist between general self efficacy, locus of control and the nursing practice environment and caring efficacy and job satisfaction? Background: Important characteristics of current nursing practice include nurses having the ability to develop and continue therapeutic relationships with patients, nurses having autonomy and control over the practice environment and nurses having more involvement in decision making. In addition, employee satisfaction is enhanced when organisations offer access to authority. Despite this, nurses continue to complain of feeling powerless in their ability to make decisions. Sample: The study population and criteria for selection included Registered Nurses in Australia who were at the time members of an Australian professional and industrial organisation. Methods: A cross-sectional survey was undertaken. Data analysis was conducted using descriptive and bivariate statistics, and structural equation modelling. Results: The model fit the data well (χ² = 2.3594, χ²/df = 2.3594 and CFI = 0.9987). Twenty four percent of variation in caring efficacy (CE) can be accounted for by general self-efficacy (GSE); work locus of control (WLC) and practice environment (PE) and 62% of the variation in job satisfaction (JS) can be accounted for by GSE, WLC and PE. All pathways were found to be significant except PE to CE. GSE positively explained CE (β = 0.38). WLC was negatively related to CE i.e., as CE scores increased WLC scores decreased (β = -0.23). Further testing of the model found CE was positively related to GSE (βZ = 0.38, p < 0.001) and negatively related to WLC (βZ = - 0.23, p = 0.001). PE was not significantly associated with CE (βZ = - 0.01, p = 0.85). JS was explained by PE, which was positively related (βZ = 0.69, p = < 0.001); GSE which was negatively related (βZ - 0 .09, p < 0.001) and WLC, which was also negatively related (βZ = - 0.20, p < 0.001). Implications for Practice Nursing and organisational leaders should ensure the development of strategies for professional development and orientation programmes which may enhance nurses’ ability to develop caring relationships and express caring behaviours to their patients and as a result improve organisational and patient outcomes. Nursing shortages and turnover rates are associated with job satisfaction and the nursing practice environment. Improving the nursing environment can produce benefits to the health system such as better job satisfaction, improved workforce retention and better patient outcomes.

Efficient articulated trajectory reconstruction using dynamic programming and filters

This paper considers the problem of reconstructing the motion of a 3D articulated tree from 2D point correspondences subject to some temporal prior. Hitherto, smooth motion has been encouraged using a trajectory basis, yielding a hard combinatorial problem with time complexity growing exponentially in the number of frames. Branch and bound strategies have previously attempted to curb this complexity whilst maintaining global optimality. However, they provide no guarantee of being more efficient than exhaustive search. Inspired by recent work which reconstructs general trajectories using compact high-pass filters, we develop a dynamic programming approach which scales linearly in the number of frames, leveraging the intrinsically local nature of filter interactions. Extension to affine projection enables reconstruction without estimating cameras.

Early adolescents’ helping behaviours when a friend is injured in a fight : the role of an extended Theory of Planned Behavior

This paper examines the role of first aid training in increasing adolescent helping behaviours when taught in a school-based injury prevention program, Skills for Preventing Injury in Youth (SPIY). The research involved the development and application of an extended Theory of Planned Behaviour (TPB), including “behavioural willingness in a fight situation,” “first aid knowledge” and “perceptions of injury seriousness”, to predict the relationship between participation in SPIY and helping behaviours when a friend is injured in a fight. From 35 Queensland high schools, 2500 Year 9 students (mean age = 13.5, 40% male) completed surveys measuring their attitudes, perceived behavioural control, subjective norms and behavioural intention, from the TPB, and added measures of behavioural willingness in a fight situation, perceptions of injury seriousness and first aid knowledge, to predict helping behaviours when a friend is injured in a fight. It is expected that the TPB will significantly contribute to understanding the relationship between participation in SPIY and helping behaviours when a friend is injured in a fight. Further analyses will determine whether the extension of the model significantly increases the variance explained in helping behaviours. The findings of this research will provide insight into the critical factors that may increase adolescent bystanders’ actions in injury situations.

A proposed Australian industrial control system security curriculum

The security of industrial control systems in critical infrastructure is a concern for the Australian government and other nations. There is a need to provide local Australian training and education for both control system engineers and information technology professionals. This paper proposes a postgraduate curriculum of four courses to provide knowledge and skills to protect critical infrastructure industrial control systems. Our curriculum is unique in that it provides security awareness but also the advanced skills required for security specialists in this area. We are aware that in the Australian context there is a cultural gap between the thinking of control system engineers who are responsible for maintaining and designing critical infrastructure and information technology professionals who are responsible for protecting these systems from cyber attacks. Our curriculum aims to bridge this gap by providing theoretical and practical exercises that will raise the awareness and preparedness of both groups of professionals.

Measurement of environmental constructs in disability assessment instruments

The International Classification of Functioning, Disability and Health (ICF) assumes a biopsychosocial basis for disability and provides a framework for understanding how environmental factors contribute to the experience of disability. To determine the utility of prevalent disability assessment instruments, the authors examined the extent to which a range of such instruments addressed the impact of environmental factors on the individual and whether the instruments designed for different disability groups focused differentially on the environment. Items from 20 widely used disability assessment instruments were linked to the five chapters of the ICF environment component using standardized classification rules. Nineteen of the 20 instruments reviewed measured the environment to varying degrees. It was determined that environmental factors from the Natural Environment and Attitudes chapters were not well accommodated by the majority of instruments. Instruments developed for people with intellectual disabilities had the greatest environmental coverage. Only one instrument provided a relatively comprehensive and economical account of environmental barriers. The authors conclude that ICF classification of environmental factors provides a valuable resource for evaluating the environmental content of existing disability-related instruments, and that it may also provide a useful framework for revising instruments in use and for developing future disability assessment instruments.

Returning to the roots of culture : a review and re-conceptualisation of safety culture

Despite significant research, there is still little agreement over how to define safety culture or of what it is comprised. Due to this lack of agreement, much of the safety culture research has little more than safety management strategies in common. There is, however, a degree of acceptance of the close relationship between safety culture and organisational culture. Organisational culture can be described using traditional views of culture drawn from the anthropology and cultural psychology literature. However, the safety culture literature rarely ventures beyond organisational culture into discussions of these more traditional concepts of culture. There is a need to discuss how these concepts of culture can be applied to safety culture to provide greater understanding of safety culture and additional means by which to approach safety in the workplace. This review explores how three traditional conceptualisations of culture; the normative, anthropological and pragmatist conceptualisations, can and have been be applied to safety culture. Finally the review proposes a synthesised conceptualisation of safety culture which can be used to provide greater depth and practical applicability of safety culture, by increasing our understanding of the interactions between cultural and contextual variables in a given workplace and the effect they have on safety.

iRAP Malaysia training course: Decade of Action for Road Safety. Report to Department of Foreign Affairs and Trade, Australia-Malaysia Institute

The International Road Assessment Program (iRAP) is a not-for-profit organisation that works in partnership with governments and non-government organisations in all parts of the world to make roads safe. The iRAP Malaysia pilot study on 3,700km of road identified the potential to save 31,800 deaths and serious injuries over the next 20 years from proven engineering improvements. To help ensure the iRAP data and results are available to planners and engineers, iRAP, together with staff from the Centre for Accident Research and Road Safety – Queensland (CARRS-Q) and the Malaysian Institute of Road Safety Research (MIROS) developed a 5-day iRAP training course that covers the background, theory and practical application of iRAP protocols, with a special focus on Malaysian case studies. Funding was provided by a competitive grant from the Australian-Malaysia Institute.