963 resultados para Electricity use


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Queensland's new State Planning Policy for Coastal Protection, released in March and approved in April 2011 as part of the Queensland Coastal Plan, stipulates that local governments prepare and implement adaptation strategies for built up areas projected to be subject to coastal hazards between present day and 2100. Urban localities within the delineated coastal high hazard zone (as determined by models incorporating a 0.8 meter rise in sea level and a 10% increase in the maximum cyclone activity) will be required to re-evaluate their plans to accommodate growth, revising land use plans to minimise impacts of anticipated erosion and flooding on developed areas and infrastructure. While implementation of such strategies would aid in avoidance or minimisation of risk exposure, communities are likely to face significant challenges in such implementation, especially as development in Queensland is so intensely focussed upon its coasts with these new policies directing development away from highly desirable waterfront land. This paper examines models of planning theory to understand how we plan when faced with technically complex problems towards formulation of a framework for evaluating and improving practice.

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This paper presents an experiment designed to investigate if redundancy in an interface has any impact on the use of complex interfaces by older people and people with low prior-experience with technology. The important findings of this study were that older people (65+ years) completed the tasks on the Words only based interface faster than on Redundant (text and symbols) interface. The rest of the participants completed tasks significantly faster on the Redundant interface. From a cognitive processing perspective, sustained attention (one of the functions of Central Executive) has emerged as one of the important factors in completing tasks on complex interfaces faster and with fewer of errors.

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The Queensland University of Technology (QUT) allows the presentation of a thesis for the Degree of Doctor of Philosophy in the format of published or submitted papers, where such papers have been published, accepted or submitted during the period of candidature. This thesis is composed of seven published/submitted papers, of which one has been published, three accepted for publication and the other three are under review. This project is financially supported by an Australian Research Council (ARC) Discovery Grant with the aim of proposing strategies for the performance control of Distributed Generation (DG) system with digital estimation of power system signal parameters. Distributed Generation (DG) has been recently introduced as a new concept for the generation of power and the enhancement of conventionally produced electricity. Global warming issue calls for renewable energy resources in electricity production. Distributed generation based on solar energy (photovoltaic and solar thermal), wind, biomass, mini-hydro along with use of fuel cell and micro turbine will gain substantial momentum in the near future. Technically, DG can be a viable solution for the issue of the integration of renewable or non-conventional energy resources. Basically, DG sources can be connected to local power system through power electronic devices, i.e. inverters or ac-ac converters. The interconnection of DG systems to power system as a compensator or a power source with high quality performance is the main aim of this study. Source and load unbalance, load non-linearity, interharmonic distortion, supply voltage distortion, distortion at the point of common coupling in weak source cases, source current power factor, and synchronism of generated currents or voltages are the issues of concern. The interconnection of DG sources shall be carried out by using power electronics switching devices that inject high frequency components rather than the desired current. Also, noise and harmonic distortions can impact the performance of the control strategies. To be able to mitigate the negative effect of high frequency and harmonic as well as noise distortion to achieve satisfactory performance of DG systems, new methods of signal parameter estimation have been proposed in this thesis. These methods are based on processing the digital samples of power system signals. Thus, proposing advanced techniques for the digital estimation of signal parameters and methods for the generation of DG reference currents using the estimates provided is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1. One of the main parameters of a power system signal is its frequency. Phasor Measurement (PM) technique is one of the renowned and advanced techniques used for the estimation of power system frequency. Chapter 2 focuses on an in-depth analysis conducted on the PM technique to reveal its strengths and drawbacks. The analysis will be followed by a new technique proposed to enhance the speed of the PM technique while the input signal is free of even-order harmonics. The other techniques proposed in this thesis as the novel ones will be compared with the PM technique comprehensively studied in Chapter 2. An algorithm based on the concept of Kalman filtering is proposed in Chapter 3. The algorithm is intended to estimate signal parameters like amplitude, frequency and phase angle in the online mode. The Kalman filter is modified to operate on the output signal of a Finite Impulse Response (FIR) filter designed by a plain summation. The frequency estimation unit is independent from the Kalman filter and uses the samples refined by the FIR filter. The frequency estimated is given to the Kalman filter to be used in building the transition matrices. The initial settings for the modified Kalman filter are obtained through a trial and error exercise. Another algorithm again based on the concept of Kalman filtering is proposed in Chapter 4 for the estimation of signal parameters. The Kalman filter is also modified to operate on the output signal of the same FIR filter explained above. Nevertheless, the frequency estimation unit, unlike the one proposed in Chapter 3, is not segregated and it interacts with the Kalman filter. The frequency estimated is given to the Kalman filter and other parameters such as the amplitudes and phase angles estimated by the Kalman filter is taken to the frequency estimation unit. Chapter 5 proposes another algorithm based on the concept of Kalman filtering. This time, the state parameters are obtained through matrix arrangements where the noise level is reduced on the sample vector. The purified state vector is used to obtain a new measurement vector for a basic Kalman filter applied. The Kalman filter used has similar structure to a basic Kalman filter except the initial settings are computed through an extensive math-work with regards to the matrix arrangement utilized. Chapter 6 proposes another algorithm based on the concept of Kalman filtering similar to that of Chapter 3. However, this time the initial settings required for the better performance of the modified Kalman filter are calculated instead of being guessed by trial and error exercises. The simulations results for the parameters of signal estimated are enhanced due to the correct settings applied. Moreover, an enhanced Least Error Square (LES) technique is proposed to take on the estimation when a critical transient is detected in the input signal. In fact, some large, sudden changes in the parameters of the signal at these critical transients are not very well tracked by Kalman filtering. However, the proposed LES technique is found to be much faster in tracking these changes. Therefore, an appropriate combination of the LES and modified Kalman filtering is proposed in Chapter 6. Also, this time the ability of the proposed algorithm is verified on the real data obtained from a prototype test object. Chapter 7 proposes the other algorithm based on the concept of Kalman filtering similar to those of Chapter 3 and 6. However, this time an optimal digital filter is designed instead of the simple summation FIR filter. New initial settings for the modified Kalman filter are calculated based on the coefficients of the digital filter applied. Also, the ability of the proposed algorithm is verified on the real data obtained from a prototype test object. Chapter 8 uses the estimation algorithm proposed in Chapter 7 for the interconnection scheme of a DG to power network. Robust estimates of the signal amplitudes and phase angles obtained by the estimation approach are used in the reference generation of the compensation scheme. Several simulation tests provided in this chapter show that the proposed scheme can very well handle the source and load unbalance, load non-linearity, interharmonic distortion, supply voltage distortion, and synchronism of generated currents or voltages. The purposed compensation scheme also prevents distortion in voltage at the point of common coupling in weak source cases, balances the source currents, and makes the supply side power factor a desired value.

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This thesis examines the role of mobile telephony in rural communities in Papua New Guinea (PNG). It is a threshold study which reports on research conducted in the earliest stages of mobile phone adoption in these areas. It explores the ways in which this new technology changes people’s lives, social structures and relationships. The research focuses on non-urban communities, which previously had little or no access to modern communication technologies, but which are in some cases still using traditional forms of communication such as drums. It has found that the introduction of mobile telecommunications has generally been viewed positively, although several negative concerns have been strongly felt. Specific benefits related to enhanced communication with relatives and friends living away from home villages, and use of the technology in time-critical emergencies or crises. Difficulties have arisen with respect to the cost of owning and operating a handset, as well as financial and logistical challenges when recharging handset batteries, particularly in areas with no mains electricity supply. Perceived damaging effects of mobile phone access related to sex, crime and pornography. The changes taking place are described through a social lens, by foregrounding the perceptions of villagers. The perspectives of key informants, such as telecommunication company managers, are also discussed. Employing the technique of triangulation (using different methods and sources) has helped to validate the findings of the research project. The sources constantly overlap and agree on the main themes, such as those outlined above. PNG is a developing country which performs poorly on a wide range of development indicators. A large majority of the people live outside of the major towns and cities. It is therefore worthwhile investigating the introduction of mobile phone technology in rural areas. These areas often have poor access to services, including transport, health, education and banking. Until 2007, communities in such regions fell outside of mobile phone coverage areas. In the case of all ten villages discussed in this thesis, there has never been any landline telephone infrastructure available. Therefore, this research on mobile phones is in effect documenting the first ever access to any kind of phone in these communities. This research makes a unique contribution to knowledge about the role of communication in PNG, and has implications for policy, practice and theory. In the policy arena, the thesis aids understanding of the impact which communication sector competition and regulation can have on rural and relatively isolated communities. There are three practical problems which have emerged from the research: cost, battery recharging difficulties and breakage are all major obstacles to uptake and use of mobile telephony in rural communities. Efforts to reduce usage costs, enable easier recharging, and design more robust handsets would allow for increased utilisation of mobile phones for a range of purposes. With respect to the realm of theory, this research sits amongst the most recent scholarship in the mobile phone field, located within the broader communication theory area. It recommends cautionary reading of any literature which suggests that mobile phones will reduce poverty and increase incomes in poor, rural communities in developing countries. Nonetheless, the present research adds weight to mobile phone studies which suggest that the primary advantages of mobile phones in such settings are for the satisfactions of communication of itself, and for social interaction among loved ones.

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We explored common reasons for non-use of the rapidly growing popularity of social networking sites among a sample of Australian adolescents (N = 69). Transcripts were coded by grouping responses along similar themes for non-use that had been commonly stated by participants. The primary reasons offered by adolescents were: lack of motivation, poor use of time, preference for other forms of communication, preference for engaging in other activities, cybersafety concerns, and a dislike of self-presentation online. The identification of these themes allows for a greater understanding of teenagers' decisions not to engage in the popular medium of communication and points to possible strategies that could be utilised by Web site developers in efforts to appeal to a wider teenage audience.

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In the current economy, knowledge has been recognized to be a valuable organisational asset, a crucial factor that aids organisations to succeed in highly competitive environments. Many organisations have begun projects and special initiatives aimed at fostering better knowledge sharing amongst their employees. Not surprisingly, information technology (IT) has been a central element of many of these projects and initiatives, as the potential of emerging information technologies such as Web 2.0 for enabling the process of managing organisational knowledge is recognised. This technology could be used as a collaborative system for knowledge management (KM) within enterprises. Enterprise 2.0 is the application of Web 2.0 in an organisational context. Enterprise 2.0 technologies are web-based social software that facilitate collaboration, communication and information flow in a bidirectional manner: an essential aspect of organisational knowledge management. This chapter explains how Enterprise 2.0 technologies (Web 2.0 technologies within organisations) can support knowledge management. The chapter also explores how such technologies support the codifying (technology-centred) and social network (people-centred) approaches of KM, towards bridging the current gap between these two approaches.

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This paper provides fundamental understanding for the use of cumulative plots for travel time estimation on signalized urban networks. Analytical modeling is performed to generate cumulative plots based on the availability of data: a) Case-D, for detector data only; b) Case-DS, for detector data and signal timings; and c) Case-DSS, for detector data, signal timings and saturation flow rate. The empirical study and sensitivity analysis based on simulation experiments have observed the consistency in performance for Case-DS and Case-DSS, whereas, for Case-D the performance is inconsistent. Case-D is sensitive to detection interval and signal timings within the interval. When detection interval is integral multiple of signal cycle then it has low accuracy and low reliability. Whereas, for detection interval around 1.5 times signal cycle both accuracy and reliability are high.

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For millennia humans have sought, organized, and used information as they learned and evolved patterns of human information behaviors to resolve their human problems and survive. However, despite the current focus on living in an "information age," we have a limited evolutionary understanding of human information behavior. In this article the authors examine the current three interdisciplinary approaches to conceptualizing how humans have sought information including (a) the everyday life information seeking-sense-making approach, (b) the information foraging approach, and (c) the problem-solution perspective on information seeking approach. In addition, due to the lack of clarity regarding the role of information use in information behavior, a fourth information approach is provided based on a theory of information use. The use theory proposed starts from an evolutionary psychology notion that humans are able to adapt to their environment and survive because of our modular cognitive architecture. Finally, the authors begin the process of conceptualizing these diverse approaches, and the various aspects or elements of these approaches, within an integrated model with consideration of information use. An initial integrated model of these different approaches with information use is proposed.

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Background: The objective of this study was to scrutinize number line estimation behaviors displayed by children in mathematics classrooms during the first three years of schooling. We extend existing research by not only mapping potential logarithmic-linear shifts but also provide a new perspective by studying in detail the estimation strategies of individual target digits within a number range familiar to children. Methods: Typically developing children (n = 67) from Years 1 – 3 completed a number-to-position numerical estimation task (0-20 number line). Estimation behaviors were first analyzed via logarithmic and linear regression modeling. Subsequently, using an analysis of variance we compared the estimation accuracy of each digit, thus identifying target digits that were estimated with the assistance of arithmetic strategy. Results: Our results further confirm a developmental logarithmic-linear shift when utilizing regression modeling; however, uniquely we have identified that children employ variable strategies when completing numerical estimation, with levels of strategy advancing with development. Conclusion: In terms of the existing cognitive research, this strategy factor highlights the limitations of any regression modeling approach, or alternatively, it could underpin the developmental time course of the logarithmic-linear shift. Future studies need to systematically investigate this relationship and also consider the implications for educational practice.

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Water resources are known to contain radioactive materials, either from natural or anthropogenic sources. Treatment, including wastewater treatment, of water for drinking, domestic, agricultural and industrial purposes has the potential to concentrate radioactive materials. Inevitably concentrated radioactive material is discharged to the environment as a waste product, reused for soil conditioning, or perhaps recycled as a new potable water supply. This thesis, presented as a collection of peer reviewed scientific papers, explores a number of water / wastewater treatment applications, and the subsequent nature and potential impact of radioactive residues associated with water exploitation processes. The thesis draws together research outcomes for sites predominantly throughout Queensland, Australia, where it is recognised that there is a paucity of published data on the subject. This thesis contributes to current knowledge on the monitoring, assessment and potential for radiation exposure from radioactive residues associated with the water industry.