885 resultados para Estuarine and fluvial systems
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Widespread adoption by electricity utilities of Non-Conventional Instrument Transformers, such as optical or capacitive transducers, has been limited due to the lack of a standardised interface and multi-vendor interoperability. Low power analogue interfaces are being replaced by IEC 61850 9 2 and IEC 61869 9 digital interfaces that use Ethernet networks for communication. These ‘process bus’ connections achieve significant cost savings by simplifying connections between switchyard and control rooms; however the in-service performance when these standards are employed is largely unknown. The performance of real-time Ethernet networks and time synchronisation was assessed using a scale model of a substation automation system. The test bed was constructed from commercially available timing and protection equipment supplied by a range of vendors. Test protocols have been developed to thoroughly evaluate the performance of Ethernet networks and network based time synchronisation. The suitability of IEEE Std 1588 Precision Time Protocol (PTP) as a synchronising system for sampled values was tested in the steady state and under transient conditions. Similarly, the performance of hardened Ethernet switches designed for substation use was assessed under a range of network operating conditions. This paper presents test methods that use a precision Ethernet capture card to accurately measure PTP and network performance. These methods can be used for product selection and to assess ongoing system performance as substations age. Key findings on the behaviour of multi-function process bus networks are presented. System level tests were performed using a Real Time Digital Simulator and transformer protection relay with sampled value and Generic Object Oriented Substation Events (GOOSE) capability. These include the interactions between sampled values, PTP and GOOSE messages. Our research has demonstrated that several protocols can be used on a shared process bus, even with very high network loads. This should provide confidence that this technology is suitable for transmission substations.
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Understanding the physical characteristics of the indoor environment that affect human health and wellbeing is the key requirement underpinning the beneficial design of a healthcare facility (HCF). We reviewed and summarised physical factors of the indoor environment reported to affect human health and wellbeing in HCFs. Research materials included articles identified in a Pubmed search, guidelines, books, reports and monographs, as well as the bibliographies of review articles in the area studied. Of these, 209 publications were selected for this review. According to the literature, there is evidence that the following physical factors of the indoor environment affect the health and wellbeing of human beings in an HCF: safety, ventilation and HVAC systems, thermal environment, acoustic environment, interior layout and room type, windows (including daylight and views), nature and gardens, lighting, colour, floor covering, furniture and its placement, ergonomics, wayfinding, artworks and music. Some of these, in themselves, directly promote or hinder health and wellbeing, but the physical factors may also have numerous indirect impacts by influencing the behaviour, actions, and interactions of patients, their families and the staff members. The findings of this research enable a good understanding of the different physical factors of the indoor environment on health and wellbeing and provide a practical resource for those responsible for the design and operate the facilities as well as researchers investigating these factors. However, more studies are needed in order to inform the design of optimally beneficial indoor environments in HCFs for all user groups.
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This paper proposes a unique and innovative approach to integrate transit signal priority control into a traffic adaptive signal control strategy. The proposed strategy was named OSTRAC (Optimized Strategy for integrated TRAffic and TRAnsit signal Control). The cornerstones of OSTRAC include an online microscopic traffic f low prediction model and a Genetic Algorithm (GA) based traffic signal timing module. A sensitivity analysis was conducted to determine the critical GA parameters. The developed traffic f low model demonstrated reliable prediction results through a test. OSTRAC was evaluated by comparing its performance to three other signal control strategies. The evaluation results revealed that OSTRAC efficiently and effectively reduced delay time of general traffic and also transit vehicles.
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The role of Information and Communications Technology (ICT) has been identified as an important factor by the United Nations in achieving the millennium development goals (UNAPCICT, 2012)1. The potential for ICT has been identified as a means to reducing poverty, creating global communities by providing access to the internet and mobile networks to rural communities, improving education services, medical services, and information availability. As of today, significant amounts of funds have been invested by the governments and donor organizations in ‘Information and Communication Technologies for Development (ICT4D)’projects by establishing telecenters, e-villages, e-health, electronic and mobile banking, and egovernment systems for citizens in general, and more specifically, rural communities to bridge the digital divide (Heeks & Molla, 2009).
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Shared services have gained significance as an organizational arrangement, in particular for support functions, to reduce costs, increase quality and create new capabilities. The Information Systems (IS) function is amenable to sharing arrangements and information systems can enable sharing in other functional areas. However, despite being a promising area for IS research, literature on shared services in the IS discipline is scarce and scattered. There is still little consensus on what shared services is. Moreover, a thorough understanding of why shared services are adopted, who are involved, and how things are shared is lacking. In this article, we set out to progress IS research on shared services by establishing a common ground for future research and proposing a research agenda to shape the field based on an analysis of the IS literature. We present a holistic and inclusive definition, discuss the primacy of economic-strategic objectives so far, and introduce conceptual frameworks for stakeholders and the notion of sharing. We also provide an overview of the theories and research methods applied. We propose a research agenda that addresses fundamental issues related to objectives, stakeholders, and the notion of sharing to lay the foundation for taking IS research on shared services forward.
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Biological systems exhibit a wide range of contextual effects, and this often makes it difficult to construct valid mathematical models of their behaviour. In particular, mathematical paradigms built upon the successes of Newtonian physics make assumptions about the nature of biological systems that are unlikely to hold true. After discussing two of the key assumptions underlying the Newtonian paradigm, we discuss two key aspects of the formalism that extended it, Quantum Theory (QT). We draw attention to the similarities between biological and quantum systems, motivating the development of a similar formalism that can be applied to the modelling of biological processes.
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Media and Information Literacy is the focus of several teaching and research projects at Queensland University of Technology and there is particular emphasis placed on digital technologies and how they are used for communication, information use and learning in formal contexts such as schools. Research projects are currently taking place in several locations where investigators are collecting data on approaches to the use of digital media tools like cameras and editing systems, tablet computers and video games. This complements QUT’s teacher preparation courses, including preparation to implement UNESCO’s Online Course in Media and Information Literacy and Intercultural Dialogue in 2013. This work takes place in the context of projects occurring at the National level in Australia that continue to promote Media and Information Literacy.
Analysis and optimisation of the preferences of decision-makers in black-start group decision-making
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As the first stage of power system restoration after a blackout, an optimal black-start scheme is very important for speeding up the whole restoration procedure. Up to now, much research work has been done on generating or selecting an optimal black-start scheme by a single round of decision-making. However, less attention has been paid for improving the final decision-making results through a multiple-round decision-making procedure. In the group decision-making environment, decision-making results evaluated by different black-start experts may differ significantly with each other. Thus, the consistency of black-start decision-making results could be deemed as an important indicator in assessing the black-start group decision-making results. Given this background, an intuitionistic fuzzy distance-based method is presented to analyse the consistency of black-start group decision-making results. Moreover, the weights of black-start indices as well as the weights of decision-making experts are modified in order to optimise the consistency of black-start group decision-making results. Finally, an actual example is served for demonstrating the proposed method.
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The exchange between the body and architecture walks a fine line between violence and pleasure. It is through the body that the subject engages with the architectural act, not via thought or reason, but through action. The materiality of architecture is the often the catalyst for some intense association; the wall that defines gender or class, the double bolted door that incarcerates, the enclosed privacy of the bedroom to the love affair. Architecture is the physical manifestation of Lefebvre’s inscribed space. It enacts the social and political systems through bodily occupation. Architecture, when tested by the occupation of bodies, anchors ideology in both space and time. The architect’s script can be powerful when rehearsed honestly to the building’s intentions and just as beautiful when rebuked by the act of protest or unfaithful occupation. This research examines this fine line of violence and pleasure in architecture through performance, in the work of Bryony Lavin’s play Stockholm and Revolving Door by Allora & Calzadilla as part of the recent Kaldor Public Art Projects exhibition 13 Rooms in Sydney. The research is underpinned by the work of Architect and theorist, Bernard Tschumi in his two essays, Violence of Architecture and The Pleasure of Architecture. Studying architecture through the lens of performance shifts the focus of examination from pure thought to the body; because architecture is occupied through the body and not the mind.
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Introduction: The use of amorphous-silicon electronic portal imaging devices (a-Si EPIDs) for dosimetry is complicated by the effects of scattered radiation. In photon radiotherapy, primary signal at the detector can be accompanied by photons scattered from linear accelerator components, detector materials, intervening air, treatment room surfaces (floor, walls, etc) and from the patient/phantom being irradiated. Consequently, EPID measurements which presume to take scatter into account are highly sensitive to the identification of these contributions. One example of this susceptibility is the process of calibrating an EPID for use as a gauge of (radiological) thickness, where specific allowance must be made for the effect of phantom-scatter on the intensity of radiation measured through different thicknesses of phantom. This is usually done via a theoretical calculation which assumes that phantom scatter is linearly related to thickness and field-size. We have, however, undertaken a more detailed study of the scattering effects of fields of different dimensions when applied to phantoms of various thicknesses in order to derive scattered-primary ratios (SPRs) directly from simulation results. This allows us to make a more-accurate calibration of the EPID, and to qualify the appositeness of the theoretical SPR calculations. Methods: This study uses a full MC model of the entire linac-phantom-detector system simulated using EGSnrc/BEAMnrc codes. The Elekta linac and EPID are modelled according to specifications from the manufacturer and the intervening phantoms are modelled as rectilinear blocks of water or plastic, with their densities set to a range of physically realistic and unrealistic values. Transmissions through these various phantoms are calculated using the dose detected in the model EPID and used in an evaluation of the field-size-dependence of SPR, in different media, applying a method suggested for experimental systems by Swindell and Evans [1]. These results are compared firstly with SPRs calculated using the theoretical, linear relationship between SPR and irradiated volume, and secondly with SPRs evaluated from our own experimental data. An alternate evaluation of the SPR in each simulated system is also made by modifying the BEAMnrc user code READPHSP, to identify and count those particles in a given plane of the system that have undergone a scattering event. In addition to these simulations, which are designed to closely replicate the experimental setup, we also used MC models to examine the effects of varying the setup in experimentally challenging ways (changing the size of the air gap between the phantom and the EPID, changing the longitudinal position of the EPID itself). Experimental measurements used in this study were made using an Elekta Precise linear accelerator, operating at 6MV, with an Elekta iView GT a-Si EPID. Results and Discussion: 1. Comparison with theory: With the Elekta iView EPID fixed at 160 cm from the photon source, the phantoms, when positioned isocentrically, are located 41 to 55 cm from the surface of the panel. At this geometry, a close but imperfect agreement (differing by up to 5%) can be identified between the results of the simulations and the theoretical calculations. However, this agreement can be totally disrupted by shifting the phantom out of the isocentric position. Evidently, the allowance made for source-phantom-detector geometry by the theoretical expression for SPR is inadequate to describe the effect that phantom proximity can have on measurements made using an (infamously low-energy sensitive) a-Si EPID. 2. Comparison with experiment: For various square field sizes and across the range of phantom thicknesses, there is good agreement between simulation data and experimental measurements of the transmissions and the derived values of the primary intensities. However, the values of SPR obtained through these simulations and measurements seem to be much more sensitive to slight differences between the simulated and real systems, leading to difficulties in producing a simulated system which adequately replicates the experimental data. (For instance, small changes to simulated phantom density make large differences to resulting SPR.) 3. Comparison with direct calculation: By developing a method for directly counting the number scattered particles reaching the detector after passing through the various isocentric phantom thicknesses, we show that the experimental method discussed above is providing a good measure of the actual degree of scattering produced by the phantom. This calculation also permits the analysis of the scattering sources/sinks within the linac and EPID, as well as the phantom and intervening air. Conclusions: This work challenges the assumption that scatter to and within an EPID can be accounted for using a simple, linear model. Simulations discussed here are intended to contribute to a fuller understanding of the contribution of scattered radiation to the EPID images that are used in dosimetry calculations. Acknowledgements: This work is funded by the NHMRC, through a project grant, and supported by the Queensland University of Technology (QUT) and the Royal Brisbane and Women's Hospital, Brisbane, Australia. The authors are also grateful to Elekta for the provision of manufacturing specifications which permitted the detailed simulation of their linear accelerators and amorphous-silicon electronic portal imaging devices. Computational resources and services used in this work were provided by the HPC and Research Support Group, QUT, Brisbane, Australia.
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Comments on “Qualification Profile of University Professors in Business and Information Systems Engineering (BISE)”
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This paper proposes a distributed control approach to coordinate multiple energy storage units (ESUs) to avoid violation of voltage and thermal constraints, which are some of the main power quality challenges for future distribution networks. ESUs usually are connected to a network through voltage source converters. In this paper, both ESU converters active and reactive power are used to deal with the above mentioned power quality issues. ESUs' reactive power is proposed to be used for voltage support, while the active power is to be utilized in managing network loading. Two typical distribution networks are used to apply the proposed method, and the simulated results are illustrated in this paper to show the effectiveness of this approach.
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Classifier selection is a problem encountered by multi-biometric systems that aim to improve performance through fusion of decisions. A particular decision fusion architecture that combines multiple instances (n classifiers) and multiple samples (m attempts at each classifier) has been proposed in previous work to achieve controlled trade-off between false alarms and false rejects. Although analysis on text-dependent speaker verification has demonstrated better performance for fusion of decisions with favourable dependence compared to statistically independent decisions, the performance is not always optimal. Given a pool of instances, best performance with this architecture is obtained for certain combination of instances. Heuristic rules and diversity measures have been commonly used for classifier selection but it is shown that optimal performance is achieved for the `best combination performance' rule. As the search complexity for this rule increases exponentially with the addition of classifiers, a measure - the sequential error ratio (SER) - is proposed in this work that is specifically adapted to the characteristics of sequential fusion architecture. The proposed measure can be used to select a classifier that is most likely to produce a correct decision at each stage. Error rates for fusion of text-dependent HMM based speaker models using SER are compared with other classifier selection methodologies. SER is shown to achieve near optimal performance for sequential fusion of multiple instances with or without the use of multiple samples. The methodology applies to multiple speech utterances for telephone or internet based access control and to other systems such as multiple finger print and multiple handwriting sample based identity verification systems.
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This grounded theory study examined the practices of twenty-one Australian early childhood teachers who work with children experiencing parental separation and divorce. Findings showed that teachers constructed personalised support for these children. Teachers’ pedagogical decision-making processes had five phases: constructing their knowledge, applying their knowledge, applying decision-making schema, taking action, and monitoring action and evaluating. This study contributes new understandings about teachers’ work with young children experiencing parental separation and divorce, and extends existing theoretical frameworks related to the provision of support. It adds to scholarship by applying grounded theory methodology in a new context. Recommendations are made for school policies and procedures within and across schools and school systems.
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Indigenous peoples have survived the most inhumane acts and violations against them. Despite acts of genocide, Aboriginal Australians and Native Americans have survived. The impact of the past 500 years cannot be separated from understandings of education for Native Americans in the same way that the impact of the past 220 years cannot be separated from the understandings of Australian Aboriginal people’s experiences of education. This chapter is about comparisons in Aboriginal and Native American communities and their collision with the dominant, white European settlers who came to Australia and America. Chomsky (Intervention in Vietnam and Central America: parallels and differences. In: Peck J (ed) The Chomsky Reader. Pantheon Books, New York, p 315, 1987) once remarked that if one took two historical events and compared them for similarities and differences, you would find both. The real test was whether on the similarities they were significant. The position of the coauthors of this chapter is in the affirmative and we take this occasion to lay them out for analysis and review. The chapter begins with a discussion of the historical legacy of oppression and colonization impacting upon Indigenous peoples in Australia and in the United States, followed by a discussion of the plight of Indigenous children in a specific State in America. Through the lens of social justice, we examine those issues and attitudes that continue to subjugate these same peoples in the economic and educational systems of both nations. The final part of the chapter identifies some implications for school leadership.