177 resultados para mismatched uncertainties


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How do agents with limited cognitive capacities flourish in informationally impoverished or unexpected circumstances? Aristotle argued that human flourishing emerged from knowing about the world and our place within it. If he is right, then the virtuous processes that produce knowledge, best explain flourishing. Influenced by Aristotle, virtue epistemology defends an analysis of knowledge where beliefs are evaluated for their truth and the intellectual virtue or competences relied on in their creation. However, human flourishing may emerge from how degrees of ignorance are managed in an uncertain world. Perhaps decision-making in the shadow of knowledge best explains human wellbeing—a Bayesian approach? In this dissertation I argue that a hybrid of virtue and Bayesian epistemologies explains human flourishing—what I term homeostatic epistemology. Homeostatic epistemology supposes that an agent has a rational credence p when p is the product of reliable processes aligned with the norms of probability theory; whereas an agent knows that p when a rational credence p is the product of reliable processes such that: 1) p meets some relevant threshold for belief (such that the agent acts as though p were true and indeed p is true), 2) p coheres with a satisficing set of relevant beliefs and, 3) the relevant set of beliefs is coordinated appropriately to meet the integrated aims of the agent. Homeostatic epistemology recognizes that justificatory relationships between beliefs are constantly changing to combat uncertainties and to take advantage of predictable circumstances. Contrary to holism, justification is built up and broken down across limited sets like the anabolic and catabolic processes that maintain homeostasis in the cells, organs and systems of the body. It is the coordination of choristic sets of reliably produced beliefs that create the greatest flourishing given the limitations inherent in the situated agent.

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Double-pass counter flow v-grove collector is considered one of the most efficient solar air-collectors. In this design of the collector, the inlet air initially flows at the top part of the collector and changes direction once it reaches the end of the collector and flows below the collector to the outlet. A mathematical model is developed for this type of collector and simulation is carried out using MATLAB programme. The simulation results were verified with three distinguished research results and it was found that the simulation has the ability to predict the performance of the air collector accurately as proven by the comparison of experimental data with simulation. The difference between the predicted and experimental results is, at maximum, approximately 7% which is within the acceptable limit considering some uncertainties in the input parameter values to allow comparison. A parametric study was performed and it was found that solar radiation, inlet air temperature, flow rate and length has a significant effect on the efficiency of the air collector. Additionally, the results are compared with single flow V-groove collector.

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Many industry peak and professional bodies advocate students undertake professional work placements as a key work integrated learning (WIL) experience in accredited university degree courses. However, mismatched expectations and gaps in the way industry partners (IPs) are supported during these work placements can place these high-stake alliances at risk. A review of models and strategies supporting industry partners indicates many are contingent on the continued efforts of well-networked individuals in both universities and IP organisations to make these connections work. It is argued that whilst these individuals are highly valued they often end up representing a whole course or industry perspective, not just their area of expertise. Sustainable partnership principles and practices with shared responsibility across stakeholder groups are needed instead. This paper provides an overview of work placement approaches in the disciplines of business, engineering and urban development at an Australian, metropolitan university. Employing action research and participatory focus group methodologies, it gathers and articulates recommendations from associated IPs on practical suggestions and strategies to improve relationships and the resultant quality of placements.

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In this paper we argue that rationalist ‘predict then act’ approaches to disaster risk management (DRM) policy promote unrealistic public expectations of DRM provisions, the avoidance of decision making by political elites, an over-reliance on technical expertise and engineering solutions to reducing exposure to natural events, and a reactive approach to DRM overall. We propose an alternative incrementalist approach that focuses on managing uncertainties rather than reducing them and building resilience not simply through the reduction of hazard exposure, but also through the ongoing reduction of community vulnerability, the explicit consideration of normative priorities, and more effective community engagement in climate risk debates.

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We come together as editors to prepare an introduction to this international volume at a time of economic turbulence, new uncertainties about the future, and a growing demand on the part of most governments for further alignment of education with the economy. Literacy, in particular, is in the vanguard, for literacy only too frequently is positioned as a proxy for education. What are the purposes of literacy teaching and how is it to be achieved? What counts as literacy in ‘new times,’ in ‘participatory culture’ where people ‘believe their contributions matter, and feel some degree of social connection with one another’ (Abrams and Merchant, Chapter 23)? How can everyone be included as critical citizens of the world in whatever definition of literacy we endorse? What fresh perspectives, new ways of thinking, and good ideas for the understanding of literacy are out there? What are the possibilities for the future? An exploration of these kinds of questions and their answers, however tentative, provides us, we believe, with our best defense against the uncertainties of our age. In some respects this is our overall purpose in the volume, to explore our understanding and future possibilities by bringing together critical reviews of the major theories, methods, and pedagogical advances that have taken place in the past 20 years in the field of literacy research at the primary/elementary school level. Each chapter in the volume is newly written for the Handbook while overall the book is intended to be a distillation of key thinking and theory which offers new directions for research in literacy. It aims to revisit current interpretations, make novel connections, frame new possibilities, and encourage researchers to pursue innovative and compelling lines of inquiry...

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The small and medium enterprise (SME) sector has been the major source of well-being and employment opportunities in regional Australia. Consequently, fostering the innovative capacity of SMEs in regions that are struggling to grow their economies and distribute the growth fairly while not degrading the environment has never been more important. While SMEs generally face more uncertainties in relation to resources (e.g. financial, human and social capital) when compared to larger businesses, collaborative, cuttingedge mechanisms to enhance innovation capabilities of regional SMEs are lacking. This paper responds to this gap and proposes a Living Laboratory – an open, multi-disciplinary and multi-stakeholder action research platform where innovations can be co-created, tested and evaluated in the every-day environment of SMEs – as a way to strengthen the SME sector in regional Australia.

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Double-pass counter flow v-grove collector is considered one of the most efficient solar air-collectors. In this design of the collector, the inlet air initially flows at the top part of the collector and changes direction once it reaches the end of the collector and flows below the collector to the outlet. A mathematical model is developed for this type of collector and simulation is carried out using MATLAB programme. The simulation results were verified with three distinguished research results and it was found that the simulation has the ability to predict the performance of the air collector accurately as proven by the comparison of experimental data with simulation. The difference between the predicted and experimental results is, at maximum, approximately 7% which is within the acceptable limit considering some uncertainties in the input parameter values to allow comparison. A parametric study was performed and it was found that solar radiation, inlet air temperature, flow rate and length have a significant effect on the efficiency of the air collector. Additionally, the results are compared with single flow V-groove collector.

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Plug-in electric vehicles will soon be connected to residential distribution networks in high quantities and will add to already overburdened residential feeders. However, as battery technology improves, plug-in electric vehicles will also be able to support networks as small distributed generation units by transferring the energy stored in their battery into the grid. Even though the increase in the plug-in electric vehicle connection is gradual, their connection points and charging/discharging levels are random. Therefore, such single-phase bidirectional power flows can have an adverse effect on the voltage unbalance of a three-phase distribution network. In this article, a voltage unbalance sensitivity analysis based on charging/discharging levels and the connection point of plug-in electric vehicles in a residential low-voltage distribution network is presented. Due to the many uncertainties in plug-in electric vehicle ratings and connection points and the network load, a Monte Carlo-based stochastic analysis is developed to predict voltage unbalance in the network in the presence of plug-in electric vehicles. A failure index is introduced to demonstrate the probability of non-standard voltage unbalance in the network due to plug-in electric vehicles.

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Voltage unbalance is a major power quality problem in low voltage residential feeders due to the random location and rating of single-phase rooftop photovoltaic cells (PV). In this paper, two different improvement methods based on the application of series (DVR) and parallel (DSTATCOM) custom power devices are investigated to improve the voltage unbalance problem in these feeders. First, based on the load flow analysis carried out in MATLAB, the effectiveness of these two custom power devices is studied vis-à-vis the voltage unbalance reduction in urban and semi-urban/rural feeders containing rooftop PVs. Their effectiveness is studied from the installation location and rating points of view. Later, a Monte Carlo based stochastic analysis is carried out to investigate their efficacy for different uncertainties of load and PV rating and location in the network. After the numerical analyses, a converter topology and control algorithm is proposed for the DSTATCOM and DVR for balancing the network voltage at their point of common coupling. A state feedback control, based on pole-shift technique, is developed to regulate the voltage in the output of the DSTATCOM and DVR converters such that the voltage balancing is achieved in the network. The dynamic feasibility of voltage unbalance and profile improvement in LV feeders, by the proposed structure and control algorithm for the DSTATCOM and DVR, is verified through detailed PSCAD/EMTDC simulations.

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This paper analyses the probabilistic linear discriminant analysis (PLDA) speaker verification approach with limited development data. This paper investigates the use of the median as the central tendency of a speaker’s i-vector representation, and the effectiveness of weighted discriminative techniques on the performance of state-of-the-art length-normalised Gaussian PLDA (GPLDA) speaker verification systems. The analysis within shows that the median (using a median fisher discriminator (MFD)) provides a better representation of a speaker when the number of representative i-vectors available during development is reduced, and that further, usage of the pair-wise weighting approach in weighted LDA and weighted MFD provides further improvement in limited development conditions. Best performance is obtained using a weighted MFD approach, which shows over 10% improvement in EER over the baseline GPLDA system on mismatched and interview-interview conditions.

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Increasing penetration of photovoltaic (PV) as well as increasing peak load demand has resulted in poor voltage profile for some residential distribution networks. This paper proposes coordinated use of PV and Battery Energy Storage (BES) to address voltage rise and/or dip problems. The reactive capability of PV inverter combined with droop based BES system is evaluated for rural and urban scenarios (having different R/X ratios). Results show that reactive compensation from PV inverters alone is sufficient to maintain acceptable voltage profile in an urban scenario (low resistance feeder), whereas, coordinated PV and BES support is required for the rural scenario (high resistance feeder). Constant as well as variable droop based BES schemes are analyzed. The required BES sizing and associated cost to maintain the acceptable voltage profile under both schemes is presented. Uncertainties in PV generation and load are considered, with probabilistic estimation of PV generation and randomness in load modeled to characterize the effective utilization of BES. Actual PV generation data and distribution system network data is used to verify the efficacy of the proposed method.

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Nitrous oxide (N2O) is one of the greenhouse gases that can contribute to global warming. Spatial variability of N2O can lead to large uncertainties in prediction. However, previous studies have often ignored the spatial dependency to quantify the N2O - environmental factors relationships. Few researches have examined the impacts of various spatial correlation structures (e.g. independence, distance-based and neighbourhood based) on spatial prediction of N2O emissions. This study aimed to assess the impact of three spatial correlation structures on spatial predictions and calibrate the spatial prediction using Bayesian model averaging (BMA) based on replicated, irregular point-referenced data. The data were measured in 17 chambers randomly placed across a 271 m(2) field between October 2007 and September 2008 in the southeast of Australia. We used a Bayesian geostatistical model and a Bayesian spatial conditional autoregressive (CAR) model to investigate and accommodate spatial dependency, and to estimate the effects of environmental variables on N2O emissions across the study site. We compared these with a Bayesian regression model with independent errors. The three approaches resulted in different derived maps of spatial prediction of N2O emissions. We found that incorporating spatial dependency in the model not only substantially improved predictions of N2O emission from soil, but also better quantified uncertainties of soil parameters in the study. The hybrid model structure obtained by BMA improved the accuracy of spatial prediction of N2O emissions across this study region.

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Scholars in Context: Prospects and Transitions is an edited collection of papers from Face to Face, the 1996 University of Queensland Graduate School of Education Postgraduate Conference. It presents current research undertaken in one of Australia's largest and leading centres for postgraduate research in education. The book is divided into three sections: classrooms through different lenses, in which a variety of classroom related issues are addressed through a range of frameworks; the big picture: global issues, which provides national and international perspectives on policy and cultural issues in a range of education sectors; and framing the individual: perspectives and insights, which includes different strands of research into individuals' development in the context of families and schools. Scholars in Context: Prospects and Transitions demonstrates how current researchers maintain a commitment to innovation and rigour, despite the current uncertainties that bedevil higher education. The work presented here makes a significant contribution to many fields of education research. The range of issues this collection addresses, the variety of theoretical and analytical perspectives adopted, and the scholarship evidenced in each contribution, make this text a valuable compendium of very recent work in education research.

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This work aims to promote integrity in autonomous perceptual systems, with a focus on outdoor unmanned ground vehicles equipped with a camera and a 2D laser range finder. A method to check for inconsistencies between the data provided by these two heterogeneous sensors is proposed and discussed. First, uncertainties in the estimated transformation between the laser and camera frames are evaluated and propagated up to the projection of the laser points onto the image. Then, for each pair of laser scan-camera image acquired, the information at corners of the laser scan is compared with the content of the image, resulting in a likelihood of correspondence. The result of this process is then used to validate segments of the laser scan that are found to be consistent with the image, while inconsistent segments are rejected. Experimental results illustrate how this technique can improve the reliability of perception in challenging environmental conditions, such as in the presence of airborne dust.

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Purpose The goal of this work was to set out a methodology for measuring and reporting small field relative output and to assess the application of published correction factors across a population of linear accelerators. Methods and materials Measurements were made at 6 MV on five Varian iX accelerators using two PTW T60017 unshielded diodes. Relative output readings and profile measurements were made for nominal square field sizes of side 0.5 to 1.0 cm. The actual in-plane (A) and cross-plane (B) field widths were taken to be the FWHM at the 50% isodose level. An effective field size, defined as FSeff=A·B, was calculated and is presented as a field size metric. FSeffFSeff was used to linearly interpolate between published Monte Carlo (MC) calculated kQclin,Qmsrfclin,fmsr values to correct for the diode over-response in small fields. Results The relative output data reported as a function of the nominal field size were different across the accelerator population by up to nearly 10%. However, using the effective field size for reporting showed that the actual output ratios were consistent across the accelerator population to within the experimental uncertainty of ±1.0%. Correcting the measured relative output using kQclin,Qmsrfclin,fmsr at both the nominal and effective field sizes produce output factors that were not identical but differ by much less than the reported experimental and/or MC statistical uncertainties. Conclusions In general, the proposed methodology removes much of the ambiguity in reporting and interpreting small field dosimetric quantities and facilitates a clear dosimetric comparison across a population of linacs