977 resultados para Dexter, Timothy, 1747-1806.
Resumo:
Security cues found in web browsers are meant to alert users to potential online threats, yet many studies demonstrate that security indicators are largely ineffective in this regard. Those studies have depended upon self-reporting of subjects' use or aggregate experimentation that correlate responses to sites with and without indicators. We report on a laboratory experiment using eye-tracking to follow the behavior of self-identified computer experts as they share information across popular social media websites. The use of eye-tracking equipment allows us to explore possible behavioral differences in the way experts perceive web browser security cues, as opposed to non-experts. Unfortunately, due to the use of self-identified experts, technological issues with the setup, and demographic anomalies, our results are inconclusive. We describe our initial experimental design, lessons learned in our experimentation, and provide a set of steps for others to follow in implementing experiments using unfamiliar technologies, eye-tracking specifically, subjects with different experience with the laboratory tasks, as well as individuals with varying security expertise. We also discuss recruitment and how our design will address the inherent uncertainties in recruitment, as opposed to design for an ideal population. Some of these modifications are generalizable, together they will allow us to run a larger 2x2 study, rather than a study of only experts using two different single sign-on systems.
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When using a mobile device to control a cursor on a large shared display, the interaction must be carefully planned to match the environment and purpose of the systems use. We describe a ‘democratic jukebox’ system that revealed five recommendations that should be considered when designing this type of interaction relating to providing feedback to the user; how to represent users in a multi-cursor based system; where people tend to look and their expectation of how to move their cursor; the orientation of screens and the social context; and, the use of simulated users to give the real users a sense that they are engaging with a greater audience.
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When wheels pass over insulated rail joints (IRJs) a vertical impact force is generated. The ability to measure the impact force is valuable as the force signature helps understand the behaviour of the IRJs, in particular their potential for failure. The impact forces are thought to be one of the main factors that cause damage to the IRJ and track components. Study of the deterioration mechanism helps finding new methods to improve the service life of IRJs in track. In this research, the strain-gage-based wheel load detector, for the first time, is employed to measure the wheel–rail contact-impact force at an IRJ in a heavy haul rail line. In this technique, the strain gages are installed within the IRJ assembly without disturbing the structural integrity of IRJ and arranged in a full wheatstone bridge to form a wheel load detector. The instrumented IRJ is first tested and calibrated in the lab and then installed in the field. For comparison purposes, a reference rail section is also instrumented with the same strain gage pattern as the IRJ. In this paper the measurement technique, the process of instrumentation, and tests as well as some typical data obtained from the field and the inferences are presented.
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Many computationally intensive scientific applications involve repetitive floating point operations other than addition and multiplication which may present a significant performance bottleneck due to the relatively large latency or low throughput involved in executing such arithmetic primitives on commod- ity processors. A promising alternative is to execute such primitives on Field Programmable Gate Array (FPGA) hardware acting as an application-specific custom co-processor in a high performance reconfig- urable computing platform. The use of FPGAs can provide advantages such as fine-grain parallelism but issues relating to code development in a hardware description language and efficient data transfer to and from the FPGA chip can present significant application development challenges. In this paper, we discuss our practical experiences in developing a selection of floating point hardware designs to be implemented using FPGAs. Our designs include some basic mathemati cal library functions which can be implemented for user defined precisions suitable for novel applications requiring non-standard floating point represen- tation. We discuss the details of our designs along with results from performance and accuracy analysis tests.
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This paper studies time integration methods for large stiff systems of ordinary differential equations (ODEs) of the form u'(t) = g(u(t)). For such problems, implicit methods generally outperform explicit methods, since the time step is usually less restricted by stability constraints. Recently, however, explicit so-called exponential integrators have become popular for stiff problems due to their favourable stability properties. These methods use matrix-vector products involving exponential-like functions of the Jacobian matrix, which can be approximated using Krylov subspace methods that require only matrix-vector products with the Jacobian. In this paper, we implement exponential integrators of second, third and fourth order and demonstrate that they are competitive with well-established approaches based on the backward differentiation formulas and a preconditioned Newton-Krylov solution strategy.
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Detailed representations of complex flow datasets are often difficult to generate using traditional vector visualisation techniques such as arrow plots and streamlines. This is particularly true when the flow regime changes in time. Texture-based techniques, which are based on the advection of dense textures, are novel techniques for visualising such flows. We review two popular texture based techniques and their application to flow datasets sourced from active research projects. The techniques investigated were Line integral convolution (LIC) [1], and Image based flow visualisation (IBFV) [18]. We evaluated these and report on their effectiveness from a visualisation perspective. We also report on their ease of implementation and computational overheads.
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Aim: Maternal obesity is associated with increased risk of adverse outcomes for mothers and offspring. Strategies to better manage maternal obesity are urgently needed; however, there is little evidence to assist the development of nutrition interventions during antenatal care. The present study aimed to assess maternal weight gain and dietary intakes of overweight and obese women participating in an exercise trial. Results will assist the development of interventions for the management of maternal overweight and obesity. Methods: Fifty overweight and obese pregnant women receiving antenatal care were recruited and provided dietary and weight data at baseline (12 weeks), 28 weeks, 36 weeks gestation and 6 weeks post-partum. Data collected were compared with current nutritional and weight gain recommendations. Associations used Pearson's correlation coefficient, and ANOVA assessed dietary changes over time, P < 0.05. Results: Mean prepregnancy body mass index was 34.4 ± 6.6 kg/m2. Gestational weight gain was 10.6 ± 6 kg with a wide range (−4.1 to 23.0 kg). 52% of women gained excessive weight (>11.5 kg for overweight and >9 kg for obese women). Gestational weight gain correlated with post-partum weight retention (P < 0.001). Dietary intakes did not change significantly during pregnancy. No women achieved dietary fat or dietary iron recommendations, only 11% achieved adequate dietary folate, and 38% achieved adequate dietary calcium. Very few women achieved recommended food group servings for pregnancy, with 83% consuming excess servings of non-core foods. Conclusion: Results provide evidence that early intervention and personalised support for obese pregnant women may help achieve individualised goals for maternal weight gain and dietary adequacy, but this needs to be tested in a clinical setting.
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Airports and cities inevitably recognise the value that each brings the other; however, the separation in decision-making authority for what to build, where, when and how provides a conundrum for both parties. Airports often want a say in what is developed outside of the airport fence, and cities often want a say in what is developed inside the airport fence. Defining how much of a say airports and cities have in decisions beyond their jurisdictional control is likely to be a topic that continues so long as airports and cities maintain separate formal decision-making processes for what to build, where, when and how. However, the recent Green and White Papers for a new National Aviation Policy have made early inroads to formalising relationships between Australia’s major airports and their host cities. At present, no clear indication (within practice or literature) is evident to the appropriateness of different governance arrangements for decisions to develop in situations that bring together the opposing strategic interests of airports and cities; thus leaving decisions for infrastructure development as complex decision-making spaces that hold airport and city/regional interests at stake. The line of enquiry is motivated by a lack of empirical research on networked decision-making domains outside of the realm of institutional theorists (Agranoff & McGuire, 2001; Provan, Fish & Sydow, 2007). That is, governance literature has remained focused towards abstract conceptualisations of organisation, without focusing on the minutia of how organisation influences action in real-world applications. A recent study by Black (2008) has provided an initial foothold for governance researchers into networked decision-making domains. This study builds upon Black’s (2008) work by aiming to explore and understand the problem space of making decisions subjected to complex jurisdictional and relational interdependencies. That is, the research examines the formal and informal structures, relationships, and forums that operationalise debates and interactions between decision-making actors as they vie for influence over deciding what to build, where, when and how in airport-proximal development projects. The research mobilises a mixture of qualitative and quantitative methods to examine three embedded cases of airport-proximal development from a network governance perspective. Findings from the research provide a new understanding to the ways in which informal actor networks underpin and combine with formal decision-making networks to create new (or realigned) governance spaces that facilitate decision-making during complex phases of development planning. The research is timely, and responds well to Isett, Mergel, LeRoux, Mischen and Rethemeyer’s (2011) recent critique of limitations within current network governance literature, specifically to their noted absence of empirical studies that acknowledge and interrogate the simultaneity of formal and informal network structures within network governance arrangements (Isett et al., 2011, pp. 162-166). The combination of social network analysis (SNA) techniques and thematic enquiry has enabled findings to document and interpret the ways in which decision-making actors organise to overcome complex problems for planning infrastructure. An innovative approach to using association networks has been used to provide insights to the importance of the different ways actors interact with one another, thus providing a simple yet valuable addition to the increasingly popular discipline of SNA. The research also identifies when and how different types of networks (i.e. formal and informal) are able to overcome currently known limitations to network governance (see McGuire & Agranoff, 2011), thus adding depth to the emerging body of network governance literature surrounding limitations to network ways of working (i.e. Rhodes, 1997a; Keast & Brown, 2002; Rethemeyer & Hatmaker, 2008; McGuire & Agranoff, 2011). Contributions are made to practice via the provision of a timely understanding of how horizontal fora between airports and their regions are used, particularly in the context of how they reframe the governance of decision-making for airport-proximal infrastructure development. This new understanding will enable government and industry actors to better understand the structural impacts of governance arrangements before they design or adopt them, particularly for factors such as efficiency of information, oversight, and responsiveness to change.
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Fast calculation of quantities such as in-cylinder volume and indicated power is important in internal combustion engine research. Multiple channels of data including crank angle and pressure were collected for this purpose using a fully instrumented diesel engine research facility. Currently, existing methods use software to post-process the data, first calculating volume from crank angle, then calculating the indicated work and indicated power from the area enclosed by the pressure-volume indicator diagram. Instead, this work investigates the feasibility of achieving real-time calculation of volume and power via hardware implementation on Field Programmable Gate Arrays (FPGAs). Alternative hardware implementations were investigated using lookup tables, Taylor series methods or the CORDIC (CoOrdinate Rotation DIgital Computer) algorithm to compute the trigonometric operations in the crank angle to volume calculation, and the CORDIC algorithm was found to use the least amount of resources. Simulation of the hardware based implementation showed that the error in the volume and indicated power is less than 0.1%.
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The exploratory research presented in this discussion paper was undertaken as input to a major research grant application for the Australian Research Council. The research looks at the contribution of the Australian built environment to meet social and environmental needs. The paper examines the following research questions: What are the main challenges facing the Australian built environment? What types of building innovations might address those challenges? The research questions were addressed through desk-top research, involving an international review of (1) relevant academic literature in top-tier construction management and general management journals, and (2) high profile industry reports published internationally. Future research will involve assessing the diffusion of the identified building innovations and gauging their impact on social and environmental goals.
Resumo:
Although the drivers of innovation have been studied extensively in construction, greater attention is required on how innovation diffusion can be effectively assessed within this complex and interdependent project-based industry. The authors draw on a highly cited innovation diffusion model by Rogers (2006) and develop a tailored conceptual framework to guide future empirical work aimed at assessing innovation diffusion in construction. The conceptual framework developed and discussed in this paper supports a five-stage process model of innovation diffusion namely: 1) knowledge and idea generation, 2) persuasion and evaluation; 3) decision to adopt, 4) integration and implementation, and 5) confirmation. As its theoretical contribution, this paper proposes three critical measurements constructs which can be used to assess the effectiveness of the diffusion process. These measurement constructs comprise: 1) nature and introduction of an innovative idea, 2) organizational capacity to acquire, assimilate, transform and exploit an innovation, and 3) rates of innovation facilitation and adoption. The constructs are interpreted in the project-based context of the construction industry, extending the contribution of general management theorists. Research planned by the authors will test the validity and reliability of the constructs developed in this paper.
Resumo:
People with Parkinson’s disease (PD) are at higher risk of malnutrition due to PD symptoms and pharmacotherapy side effects. Poorer outcomes are associated with higher amounts of weight loss (>5%) and lower levels of fat free mass. When pharmacotherapy is no longer effective for symptom control, deep-brain stimulation (DBS) surgery may be considered. People with PD scheduled for DBS surgery were recruited from a Brisbane neurological clinic (n=11 out of 16). The Scale for Outcomes of Parkinson’s disease –Autonomic (SCOPA-AUT), Modified Constipation Assessment Scale (MCAS), and a 3-day food diary were mailed to participants’ homes for completion prior to hospital admission. During admission, the Patient-Generated Subjective Global Assessment (PG-SGA), weight, height and body composition were assessed. Mean(±s.d.) PD duration from diagnosis and time since occurrence of PD symptoms was 9.0(±8.0) and 12(±8.8) years, respectively. Five participants reported unintentional weight loss (average loss of 15.6%). PD duration but not years since symptom onset significantly predicted PG-SGA scores (β=4.2, t(8)=2.7, p<.05). Both were positively correlated with PG-SGA score (r = .667, r=.587). On average, participants classified as well-nourished (SGA-A) (n=4) were younger, had shorter disease durations, lower PG-SGA scores, higher body mass (BMI) and fat free mass (FFMI) indices when compared to malnourished participants (SGA-B) (n=7). They also reported fewer non-motor symptoms on the SCOPA-AUT and MCAS. Three participants had previously received dietetic advice but not in relation to PD. These findings demonstrate that malnutrition remains unrecognised and untreated in this group despite unintentional weight loss and a high prevalence of malnutrition.
Resumo:
People with Parkinson’s disease (PD) have been reported to be at higher risk of malnutrition than an age-matched population due to PD motor and non-motor symptoms and pharmacotherapy side effects. The prevalence of malnutrition in PD has yet to be well-defined. Community-dwelling people with PD, aged > 18 years, were recruited (n = 97, 61 M, 36 F). The Patient-Generated Subjective Global Assessment (PGSGA) was used to assess nutritional status, the Parkinson’s Disease Questionnaire (PDQ-39) was used to assess quality of life, and the Beck’s Depression Inventory (BDI) was used to measure depression. Levodopa equivalent doses (LEDs) were calculated based on reported Parkinson’s disease medication. Weight, height, mid-arm circumference (MAC) and calf circumference were measured. Cognitive function was measured using the Addenbrooke’s Cognitive Examination. Average age was 70.0 (9.1, 35–92) years. Based on SGA, 16 (16.5%) were moderately malnourished (SGA B) while none were severely malnourished (SGA C). The well-nourished participants (SGA A) had a better quality of life, t(90) = −2.28, p < 0.05, and reported less depressive symptoms, t(94)= −2.68, p < 0.05 than malnourished participants. Age, years since diagnosis, cognitive function and LEDs did not signifi cantly differ between the groups. The well-nourished participants had lower PG-SGA scores, t(95) = −5.66, p = 0.00, higher BMIs, t(95) = 3.44, p < 0.05, larger MACs, t(95) = 3.54, p < 0.05 and larger calf circumferences, t(95) = 2.29, p < 0.05 than malnourished participants. Prevalence of malnutrition in community-dwelling adults with PD in this study is comparable to that in other studies with community-dwelling adults without PD and is higher than other PD studies where a nutritional status assessment tool was used. Further research is required to understand the primary risk factors for malnutrition in this group.
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Aim: This paper aims to explore new graduates experience working with clients with mental health issues using critical incident interviews. Methods: The qualitative research techniques were based on phenomenology. A purposive sample of 19 new graduate dietitians was drawn from a range of work settings and locations throughout Australia. Data was gathered using thirty minute Critical Incident Interviews. Audio-taped data was transcribed, coded to identify common themes, compared for congruence and then categorised into knowledge, skills and attitudes. Results: New graduates encountered a range of situations involving a variety of mental health, wellbeing, dietetic and clinical issues. Common themes highlighted the mental health knowledge, skills and attitudes required for entry-level dietitians which then informed the review of the National Competency Standards for Entry-Level Dietitians. Conclusion: New graduates encounter a variety of mental health and wellbeing issues in their everyday practice and therefore require training to address these situations competently.
Mixed methods research approach to the development and review of competency standards for dietitians
Resumo:
Aim: Competency standards support a range of professional activities including the accreditation of university courses. Reviewing these standards is essential to ensure universities continue to produce well equipped graduates, who can meet the challenge of changing workforce requirements. This paper has two aims: a) to provide an overview of the methodological approaches utilised for compilation and review of the Competency Standards for Dietetics and b) to evaluate the Dietitians Association of Australia’s Competency Standards and capture emerging and contemporary dietetic practice. Methods: A literature review of the methods used to develop Competency Standards for dietitians in Australia, including entry level, advanced level and DAA Fellow competencies and other specific areas of competency, such as public health nutrition and nutrition education is outlined and compared to other allied health professions. The mixed methods methodology used in the most recent review is described in more detail. Results: The history of Dietetic Competency Standards development and review in Australia is compared to dietetic Competency Standards internationally and within other health professions in Australia. The political context in which these standards have been developed in Australia and which has determined their format is also discussed. The results of the most recent Competency Standards review are reported to highlight emerging practice in Australia. Conclusion: The mixed methods approach used in this review provides rich data about contemporary dietetic practice. Our view supports a planned review of all Competency Standards to ensure practice informs education and credentialling and we recommend the Dietitians Association of Australia consider this in future