242 resultados para Difficult-to-Measure Nuclides


Relevância:

100.00% 100.00%

Publicador:

Resumo:

With the increasing need to adapt to new environments, data-driven approaches have been developed to estimate terrain traversability by learning the rover’s response on the terrain based on experience. Multiple learning inputs are often used to adequately describe the various aspects of terrain traversability. In a complex learning framework, it can be difficult to identify the relevance of each learning input to the resulting estimate. This paper addresses the suitability of each learning input by systematically analyzing the impact of each input on the estimate. Sensitivity Analysis (SA) methods provide a means to measure the contribution of each learning input to the estimate variability. Using a variance-based SA method, we characterize how the prediction changes as one or more of the input changes, and also quantify the prediction uncertainty as attributed from each of the inputs in the framework of dependent inputs. We propose an approach built on Analysis of Variance (ANOVA) decomposition to examine the prediction made in a near-to-far learning framework based on multi-task GP regression. We demonstrate the approach by analyzing the impact of driving speed and terrain geometry on the prediction of the rover’s attitude and chassis configuration in a Marsanalogue terrain using our prototype rover Mawson.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The integration of stochastic wind power has accentuated a challenge for power system stability assessment. Since the power system is a time-variant system under wind generation fluctuations, pure time-domain simulations are difficult to provide real-time stability assessment. As a result, the worst-case scenario is simulated to give a very conservative assessment of system transient stability. In this study, a probabilistic contingency analysis through a stability measure method is proposed to provide a less conservative contingency analysis which covers 5-min wind fluctuations and a successive fault. This probabilistic approach would estimate the transfer limit of a critical line for a given fault with stochastic wind generation and active control devices in a multi-machine system. This approach achieves a lower computation cost and improved accuracy using a new stability measure and polynomial interpolation, and is feasible for online contingency analysis.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Hospital acquired infections (HAI) are costly but many are avoidable. Evaluating prevention programmes requires data on their costs and benefits. Estimating the actual costs of HAI (a measure of the cost savings due to prevention) is difficult as HAI changes cost by extending patient length of stay, yet, length of stay is a major risk factor for HAI. This endogeneity bias can confound attempts to measure accurately the cost of HAI. We propose a two-stage instrumental variables estimation strategy that explicitly controls for the endogeneity between risk of HAI and length of stay. We find that a 10% reduction in ex ante risk of HAI results in an expected savings of £693 ($US 984).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

There is a growing literature (Arthur, Inkson, & Pringle, 1999; Collin & Young, 2000; Hall & Associates, 1996; Peiperl, Arthur,& Anand, 2002) about the changing workplace and the consequent changes to our understanding of the place of career in individuals’ lives (Richardson, 1996, 2000) - “Careers are becoming more varied and more difficult to manage for both individuals and organisations” (Arnold et al, 2005, p. 523). This chapter will present the background to the changes in the world of work and the changes which inevitably impact individuals’ careers. It will then focus on the close relationship between career development and lifelong learning and the importance of ongoing professional learning for individuals to maintain employability in a changing work world.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Principal Topic: It is well known that most new ventures suffer from a significant lack of resources, which increases the risk of failure (Shepherd, Douglas and Shanley, 2000) and makes it difficult to attract stakeholders and financing for the venture (Bhide & Stevenson, 1999). The Resource-Based View (RBV) (Barney, 1991; Wernerfelt, 1984) is a dominant theoretical base increasingly drawn on within Strategic Management. While theoretical contributions applying RBV in the domain of entrepreneurship can arguably be traced back to Penrose (1959), there has been renewed attention recently (e.g. Alvarez & Busenitz, 2001; Alvarez & Barney, 2004). This said, empirical work is in its infancy. In part, this may be due to a lack of well developed measuring instruments for testing ideas derived from RBV. The purpose of this study is to develop a measurement scales that can serve to assist such empirical investigations. In so doing we will try to overcome three deficiencies in current empirical measures used for the application of RBV to the entrepreneurship arena. First, measures for resource characteristics and configurations associated with typical competitive advantages found in entrepreneurial firms need to be developed. These include such things as alertness and industry knowledge (Kirzner, 1973), flexibility (Ebben & Johnson, 2005), strong networks (Lee et al., 2001) and within knowledge intensive contexts, unique technical expertise (Wiklund and Shepard, 2003). Second, the RBV has the important limitations of being relatively static and modelled on large, established firms. In that context, traditional RBV focuses on competitive advantages. However, newly established firms often face disadvantages, especially those associated with the liabilities of newness (Aldrich & Auster, 1986). It is therefore important in entrepreneurial contexts to expand to an investigation of responses to competitive disadvantage through an RBV lens. Conversely, recent research has suggested that resource constraints actually have a positive effect on firm growth and performance under some circumstances (e.g., George, 2005; Katila & Shane, 2005; Mishina et al., 2004; Mosakowski, 2002; cf. also Baker & Nelson, 2005). Third, current empirical applications of RBV measured levels or amounts of particular resources available to a firm. They infer that these resources deliver firms competitive advantage by establishing a relationship between these resource levels and performance (e.g. via regression on profitability). However, there is the opportunity to directly measure the characteristics of resource configurations that deliver competitive advantage, such as Barney´s well known VRIO (Valuable, Rare, Inimitable and Organized) framework (Barney, 1997). Key Propositions and Methods: The aim of our study is to develop and test scales for measuring resource advantages (and disadvantages) and inimitability for entrepreneurial firms. The study proceeds in three stages. The first stage developed our initial scales based on earlier literature. Where possible, we adapt scales based on previous work. The first block of the scales related to the level of resource advantages and disadvantages. Respondents were asked the degree to which each resource category represented an advantage or disadvantage relative to other businesses in their industry on a 5 point response scale: Major Disadvantage, Slight Disadvantage, No Advantage or Disadvantage, Slight Advantage and Major Advantage. Items were developed as follows. Network capabilities (3 items) were adapted from (Madsen, Alsos, Borch, Ljunggren & Brastad, 2006). Knowledge resources marketing expertise / customer service (3 items) and technical expertise (3 items) were adapted from Wiklund and Shepard (2003). flexibility (2 items), costs (4 items) were adapted from JIBS B97. New scales were developed for industry knowledge / alertness (3 items) and product / service advantages. The second block asked the respondent to nominate the most important resource advantage (and disadvantage) of the firm. For the advantage, they were then asked four questions to determine how easy it would be for other firms to imitate and/or substitute this resource on a 5 point likert scale. For the disadvantage, they were asked corresponding questions related to overcoming this disadvantage. The second stage involved two pre-tests of the instrument to refine the scales. The first was an on-line convenience sample of 38 respondents. The second pre-test was a telephone interview with a random sample of 31 Nascent firms and 47 Young firms (< 3 years in operation) generated using a PSED method of randomly calling households (Gartner et al. 2004). Several items were dropped or reworded based on the pre-tests. The third stage (currently in progress) is part of Wave 1 of CAUSEE (Nascent Firms) and FEDP (Young Firms), a PSED type study being conducted in Australia. The scales will be tested and analysed with a random sample of approximately 700 Nascent and Young firms respectively. In addition, a judgement sample of approximately 100 high potential businesses in each category will be included. Findings and Implications: The paper will report the results of the main study (stage 3 – currently data collection is in progress) will allow comparison of the level of resource advantage / disadvantage across various sub-groups of the population. Of particular interest will be a comparison of the high potential firms with the random sample. Based on the smaller pre-tests (N=38 and N=78) the factor structure of the items confirmed the distinctiveness of the constructs. The reliabilities are within an acceptable range: Cronbach alpha ranged from 0.701 to 0.927. The study will provide an opportunity for researchers to better operationalize RBV theory in studies within the domain of entrepreneurship. This is a fundamental requirement for the ability to test hypotheses derived from RBV in systematic, large scale research studies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The learner licence is an important component of the graduated driver licensing system. This research describes the driving and licensing experiences of learner drivers in Queensland and New South Wales licensed prior to the changes made to the system in mid-2007. The sample consisted of 392 participants who completed a telephone interview just after they obtained their provisional licence. The results suggest that learner drivers in the two states had many similar experiences when they were obtaining a learner licence. However, once a learner licence was obtained, there were differences in the amount of practice, the supervisor learners practised with, the type of vehicle they used and the amount of unlicensed driving. This paper provides important baseline descriptive data that can be used to measure the impact of the changes that were introduced to the learner licence phase in mid-2007 in both of these states.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Construction projects are faced with a challenge that must not be underestimated. These projects are increasingly becoming highly competitive, more complex, and difficult to manage. They become ‘wicked problems’, which are difficult to solve using traditional approaches. Soft Systems Methodology (SSM) is a systems approach that is used for analysis and problem solving in such complex and messy situations. SSM uses “systems thinking” in a cycle of action research, learning and reflection to help understand the various perceptions that exist in the minds of the different people involved in the situation. This paper examines the benefits of applying SSM to wicked problems in construction project management, especially those situations that are challenging to understand and difficult to act upon. It includes relevant examples of its use in dealing with the confusing situations that incorporate human, organizational and technical aspects.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Construction projects are faced with a challenge that must not be underestimated. These projects are increasingly becoming highly competitive, more complex, and difficult to manage. They become problems that are difficult to solve using traditional approaches. Soft Systems Methodology (SSM) is a systems approach that is used for analysis and problem solving in such complex and messy situations. SSM uses “systems thinking” in a cycle of action research, learning and reflection to help understand the various perceptions that exist in the minds of the different people involved in the situation. This paper examines the benefits of applying SSM to problems of knowledge management in construction project management, especially those situations that are challenging to understand and difficult to act upon. It includes five case studies of its use in dealing with the confusing situations that incorporate human, organizational and technical aspects.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Teaching literacy requires accurate and current knowledge in the field (Commonwealth of Australia, 2005). There have been persistent inquiries into what constitutes specialist knowledge and skills for teaching students to be literate. Preservice teacher education is fundamental to literacy development, which includes the approaches universities employ to prepare graduates for teaching literacy. Indeed, preservice teacher programs and literacy education also elicit insatiable media coverage. There is a continued push to improve literacy outcomes for school students across the nation and prepare the literacy knowledge and skills of Australian teachers. This study mainly focuses on 10 final-year preservice teachers attending a regional university campus who volunteered for further experiences to teach students to read traditional texts. These preservice teachers completed three university literacy units before commencing with practical applications. A literacy program, titled Reading Squadron, was developed in partnership between a local primary school and the university. Primary students were identified by the school as requiring literacy support. Preservice teachers attended a whole day training session run by school staff at the university and then visited the school for two one-hour sessions each week over a six-week period. Each preservice teacher was assigned two students and worked with each student for half an hour twice a week. The aim of this small-scale qualitative study was to investigate the perceptions of the preservice teachers and school staff as a result of their involvement in the Reading Squadron program. The preservice teachers completed a questionnaire to determine their views of the program and ascertain how it assisted their development. Further data were gathered from the preservice teachers through individual face-to-face interviews. Three school staff involved in the program also completed a questionnaire to determine the value of the program. Results indicated that the preservice teachers made links between theory and practice, and felt they gained knowledge about teaching reading. Three preservice teachers noted it was difficult to work around timetable commitments but gained from the experience and suggested embedding such experiences into university literacy units. Data gathered from school staff indicated that six-weeks was not sufficient time to measure improvements in the school students, however, they were supportive of such a program, particularly for its continuation. Collaborations between schools and universities can provide opportunities for preservice teachers to use theoretical knowledge gained from core university subjects with application to assist primary students’ literacy development in schools. Teachers in this study were supportive of the Reading Squadron program, however, more data needed to be collected to understand the literacy improvement of students. Longitudinal studies are required to ascertain specific knowledge and skills gained by preservice teachers to teach reading and how these programs enhance students’ literacy levels.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

One hundred and forty-three children (61 boys and 82 girls) between 8 and 12 years of age participated in a study which focused on closeness to significant others and its relationship with self-esteem. A closeness rating scale was developed to determine quantitatively how close children feel to their mother, father, two closest peers, and current teacher. Marsh's (1990) eight general self-concept items from the Self-Description Questionnaire 1 (SDQI), together with eight items from Burnett's (1994) Self-scale, were administered to the children, who ranged in age from 8 to 12 years, to measure their self-esteem. Closeness to mother was found to correlate most significantly with a child's self-esteem, while closeness to teacher was related more strongly to self-esteem for girls than for boys.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Confusion exists with regard to the substantive difference between self-concept and self-esteem. In an endeavour to cast some light on this confusion two studies were conducted with 1193 preadolescents using modified versions of two commonly used instruments designed to measure self-concept and self-esteem. Exploratory factor analysis indicated that both these instruments measure specific facets of the same construct, namely self.-concept. General or global self-concept proved to be a difficult construct to measure in preadolescent students.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Building integrated living systems (BILS), such as green roofs and living walls, could mitigate many of the challenges presented by climate change and biodiversity protection. However, few if any such systems have been constructed, and current tools for evaluating them are limited, especially under Australian subtropical conditions. BILS are difficult to assess, because living systems interact with complex, changing and site-specific social and environmental conditions. Our past research in design for eco-services has confirmed the need for better means of assessing the ecological values of BILS - let alone better models for assessing their thermal and hydrological performance. To address this problem, a research project is being developed jointly by researchers at the Central Queensland University (CQ University) and the Queensland University of Technology (QUT), along with industry collaborators. A mathematical model under development at CQ University will be applied and tested to determine its potential for predicting their complex, dynamic behaviour in different contexts. However, the paper focuses on the work at QUT. The QUT school of design is generating designs for living walls and roofs that provide a range of ecosystem goods and services, or ‘eco-services’, for a variety of micro-climates and functional contexts. The research at QUT aims to develop appropriate designs, virtual prototypes and quantitative methods for assessing the potential multiple benefits of BILS in subtropical climates. It is anticipated that the CQ University model for predicting thermal behaviour of living systems will provide a platform for the integration of ecological criteria and indicators. QUT will also explore means to predict and measure the value of eco-services provided by the systems, which is still largely uncharted territory. This research is ultimately intended to facilitate the eco-retrofitting of cities to increase natural capital and urban resource security - an essential component of sustainability. The talk will present the latest range of multifunctional, eco-productive living walls, roofs and urban space frames and their eco-services.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: The reasons that a patient has to start treatment, their “Cues to Action”, are important for determining subsequent health behaviours. Cues to action are an explicit component of the Health Belief Model of CPAP acceptance adherence. At present there is no scale available to measure this construct for individuals with Obstructive Sleep Apnoea (OSA). This paper aims to develop, validate and describe responding patterns within an OSA patient sample to the Cues to CPAP Use Questionnaire (CCUQ).----- Method: Participants were 63 adult patients diagnosed with OSA who had never tried CPAP when initially recruited. The CCUQ was completed at one month after being prescribed CPAP.----- Results: Exploratory factor analysis (EFA) showed a three factor structure of the 9-item CCUQ, with “Health Cues”, “Partner Cues” and “Health Professional Cues” subscales accounting for 59.91% of the total variance. The CCUQ demonstrated modest internal consistency and split-half reliability. The questionnaire is brief and user-friendly, with readability at a 7th grade level. The most frequently endorsed cues for starting CPAP were Health Professional Cues (prompting by the sleep physician) and Health Cues such as tiredness and concern about health outcomes.----- Conclusions: This study validates a measure of an important motivational component of the Health Belief Model. Health Professional Cues and internal Health Cues were reported to be the most important prompts to commence CPAP by this patient sample.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The relationship between multiple cameras viewing the same scene may be discovered automatically by finding corresponding points in the two views and then solving for the camera geometry. In camera networks with sparsely placed cameras, low resolution cameras or in scenes with few distinguishable features it may be difficult to find a sufficient number of reliable correspondences from which to compute geometry. This paper presents a method for extracting a larger number of correspondences from an initial set of putative correspondences without any knowledge of the scene or camera geometry. The method may be used to increase the number of correspondences and make geometry computations possible in cases where existing methods have produced insufficient correspondences.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A laboratory scale twin screw extruder has been interfaced with a near infrared (NIR) spectrometer via a fibre optic link so that NIR spectra can be collected continuously during the small scale experimental melt state processing of polymeric materials. This system can be used to investigate melt state processes such as reactive extrusion, in real time, in order to explore the kinetics and mechanism of the reaction. A further advantage of the system is that it has the capability to measure apparent viscosity simultaneously which gives important additional information about molecular weight changes and polymer degradation during processing. The system was used to study the melt processing of a nanocomposite consisting of a thermoplastic polyurethane and an organically modified layered silicate.