934 resultados para Power euality mitigation devices
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This paper presents a new approach to the design of a rough fuzzy controller for the control loop of the SVC (static VAR system) in a two area power system for stability enhancement with particular emphasis on providing effective damping for oscillatory instabilities. The performances of the rough fuzzy and the conventional fuzzy controller are compared with that of the conventional PI controller for a variety of transient disturbances, highlighting the effectiveness of the rough fuzzy controller in damping the inter-area oscillations. The effect of the rough fuzzy controller in improving the CCT (critical clearing time) of the two area system is elaborated in this paper as well.
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The Midwest Independent Transmission System Operator (MISO) has experienced significant amounts of wind power development within the last decade. The MISO footprint spans the majority of the upper Midwest region of the country, from the Dakotas to Indiana and as far east as Michigan. These areas have a rich wind energy resource. States in the MISO footprint have passed laws or set goals that require load serving entities to supply a portion of their load using renewable energy. In order to meet these requirements, significant investments are needed to build the transmission infrastructure necessary to deliver the power from these often remote wind energy resources to the load centers. This paper presents some of the transmission planning related work done at MISO which was largely influenced by current and future needs for increased wind power generation in the footprint. Specifically, topics covered are generator interconnection, long-term planning coordination, and cost-allocation for new transmission lines.
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The security of power transfer across a given transmission link is typically a steady state assessment. This paper develops tools to assess machine angle stability as affected by a combination of faults and uncertainty of wind power using probability analysis. The paper elaborates on the development of the theoretical assessment tool and demonstrates its efficacy using single machine infinite bus system.
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A review of the issues for supporting learning of power engineering in Australia is presented in this paper. The learning needs of students and the support available in blended learning and through distance educations are explored in this review. Specific software tools to assist the learning environment are appraised and the relevance for the next generation of power engineers assessed.
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The Cooperative Research Centre (CRC) for Rail Innovation is conducting a tranche of industry-led research projects looking into safer rail level crossings. This paper will provide an overview of the Affordable Level Crossings project, a project that is performing research in both engineering and human factors aspects of low-cost level crossing warning devices (LCLCWDs), and is facilitating a comparative trial of these devices over a period of 12 months in several jurisdictions. Low-cost level crossing warning devices (LCLCWDs) are characterised by the use of alternative technologies for high cost components including train detection and connectivity (e.g. radar, acoustic, magnetic induction train detection systems and wireless connectivity replacing traditional track circuits and wiring). These devices often make use of solar power where mains power is not available, and aim to make substantial savings in lifecycle costs. The project involves trialling low-cost level crossing warning devices in shadow-mode, where devices are installed without the road-user interface at a number of existing level crossing sites that are already equipped with conventional active warning systems. It may be possible that the deployment of lower-cost devices can provide a significantly larger safety benefit over the network than a deployment of expensive conventional devices, as the lower cost would allow more passive level crossing sites to be upgraded with the same capital investment. The project will investigate reliability and safety integrity issues of the low-cost devices, as well as evaluate lifecycle costs and investigate human factors issues related to warning reliability. This paper will focus on the requirements and safety issues of LCLCWDs, and will provide an overview of the Rail CRC projects.
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In this paper we present a fast power line detection and localisation algorithm as well as propose a high-level guidance architecture for active vision-based Unmanned Aerial Vehicle (UAV) guidance. The detection stage is based on steerable filters for edge ridge detection, followed by a line fitting algorithm to refine candidate power lines in images. The guidance architecture assumes an UAV with an onboard Gimbal camera. We first control the position of the Gimbal such that the power line is in the field of view of the camera. Then its pose is used to generate the appropriate control commands such that the aircraft moves and flies above the lines. We present initial experimental results for the detection stage which shows that the proposed algorithm outperforms two state-of-the-art line detection algorithms for power line detection from aerial imagery.
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Technologies such as smart meters and electricity feedback are becoming an increasingly compelling focus for HCI researchers in light of rising power prices and peak demand. We argue, however, that a pre-occupation with the goal of demand management has limited the scope of design for these technologies. In this paper we present our work-in-progress investigating the potential value of socially sharing electricity information as a means of broadening the scope of design for these devices. This paper outlines some preliminary findings gathered from a design workshop and a series of qualitative interviews with householders in Brisbane, Australia, regarding their attitudes towards electricity feedback and sharing consumption information. Preliminary findings suggest that; (1) the social sharing of electricity feedback information has the potential to be of value in better informing consumption decisions, however; (2) the potential for sharing may be constrained by attitudes towards privacy, trust and the possibility of misinformation being shared. We conclude by outlining ideas for our future research on this topic and invite comments on these ideas.
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With significant population growth experienced in South East Queensland over the past two decades and a high rate of growth expected to continue in coming decades, the Queensland Government is promoting urban consolidation planning policies to manage growth sustainably. Multi-residential buildings will play an important role in facilitating the increased densities which urban consolidation policies imply. However, a major flood event in January 2011 has brought to light the vulnerability of certain types of multi-residential typologies to power outages. The crisis conditions exposed how contemporary building design and construction practices, coupled with regulatory and planning issues, appear to have compromised the resilience and habitability of multi-storey residential buildings. In the greater urban area of Brisbane, Queensland, the debilitating dependence that certain types of apartment buildings have on mains electricity was highlighted by residents’ experiences of the Brisbane River flood disaster, before, during and after the event. This research examined high density residential buildings in West End, Brisbane, an inner city suburb which was severely affected by the flood and is earmarked for significant urban densification under the Brisbane City Plan. Medium-to-high-density residential buildings in the suburb were mapped in flooded and non-flooded locations and a database containing information about the buildings was created. Parameters included date of construction, number of storeys, systems of access and circulation, and potential for access to natural light and ventilation for habitable areas. A series of semi-structured interviews were conducted with residents involved in the owners’ management committees of several buildings to verify information the mapping could not provide. The interviews identified a number of critical systems failures due to power outage which had a significant impact on residents’ wellbeing, comfort and safety. Building services such as lifts, running water, fire alarms, security systems and air-conditioning ceased to operate when power was disconnected to neighbourhoods and buildings in anticipation of rising flood waters. Lack of access to buildings and dwellings, lack of safety, lack of building security, and lack of thermal comfort affected many residents whether or not their buildings were actually subjected to inundation, with some buildings rendered uninhabitable for a prolonged period. The extent of the impact on residents was dramatically influenced by the scale and type of building inhabited, with those dwelling in buildings under a 25m height limit, with a single lift, found to be most affected. The energy-dependency and strong trend of increasing power demands of high-rise buildings is well-documented. Extended electricity outages such as the one brought about by the 2011 flood in Queensland are likely to happen more frequently than the 50-year average of the flood event itself. Electricity blackouts can result from a number of man-made or natural causes, including shortages caused by demand exceeding supply. This paper highlights the vulnerability of energy-dependent buildings to power outages and investigates options for energy security for occupants of multi-storey buildings and makes recommendations to increase resilience and general liveability in multi-residential buildings in the subtropics through design modifications.
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This book explores the relationship between gender and power in Burmese history from pre-colonial times to the present day and aims to identify the sources, nature and limitations of women’s power. The study takes as its starting point the apparent contradiction that, though Burmese women historically enjoyed relatively high social status and economic influence, for the most part they remained conspicuously absent from positions of authority in formal religious, social and political institutions. The book thus examines the concept of ‘family’ in Burmese political culture, and reveals how some women were able to gain political influence through their familial connections with powerful men, even while cultural models of ‘correct’ female behaviour prevented most women from attaining official positions of political authority. The study also considers how various influences – Buddhism, colonialism, nationalism, modernisation and militarism – shaped Burmese concepts of gender and power, with important implications for how women were able to exercise social, economic and political influence. The book explores how the effects of prolonged armed conflict, economic isolation and political oppression have constrained opportunities for women to attain power in contemporary Burma, and examines opportunities opened up by the pro-democracy movement and recent focus on women's issues and rights for women to exercise influence both inside Burma and in exile. Using an interdisciplinary approach that draws on feminist, anthropological and social science discourses, placing them within an historical framework, the author offers a broad understanding of how power is obtained and exercised in Burma in order to reassess historical representations of Burmese women and so provide a more comprehensive and inclusive understanding of power relations in historical and contemporary Burma.
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This work-in-progress paper presents an ensemble-based model for detecting and mitigating Distributed Denial-of-Service (DDoS) attacks, and its partial implementation. The model utilises network traffic analysis and MIB (Management Information Base) server load analysis features for detecting a wide range of network and application layer DDoS attacks and distinguishing them from Flash Events. The proposed model will be evaluated against realistic synthetic network traffic generated using a software-based traffic generator that we have developed as part of this research. In this paper, we summarise our previous work, highlight the current work being undertaken along with preliminary results obtained and outline the future directions of our work.
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Hamstring strain injuries (HSI) are the predominant non-contact injury in many sports. Intermittent running has been shown to result in preferential reductions in eccentric hamstring strength, which increase the risk of sustaining a HSI. The eccentric specific nature of this decline in hamstring function implicates central mechanisms, as peripheral fatigue mechanisms tend to impact upon both concentric and eccentric contractions modes. However, neural function of the hamstrings, such as the median power frequency (MPF) of the surface electromyography signal has yet to be examined in the fatigued hamstring following intermittent sprint running. AIM: To determine the impact of fatigue induced by intermittent sprinting on the MPF of the medial and lateral hamstring muscles. METHODS: Fifteen recreationally active males completed 18 × 20m overground sprints. Maximal strength (concentric and eccentric knee flexor and concentric knee extensor) was determined isokinetically at the velocities of ±180.s-1 and ±60.s- while hamstring muscle activation was assessed using surface electromyography, before and 15 minutes after the running protocol. RESULTS: Overground intermittent running caused a significant reduction in eccentric knee flexor strength (27.2 Nm; 95% CI = 11.2 to 43.3; p=0.0001) but not concentric strength (9.3 Nm; 95% CI = -6.7 to 25.3; P=0.6361). Following the overground running, MPF of the lateral hamstrings showed a significant decline eccentrically (0.86; 95% CI = 0.59 to 1.54; P=0.038) and concentrically (0.76; 95%CI = 0.66 to 0.83; P=0.039). Similar declines in MPF were also noted in the medial hamstrings eccentrically (1.54; 95% CI = 0.59 to 7.9; P=0.005) and concentrically (1.18; 95% CI = 0.44 to 6.8; P=0.040). CONCLUSION: Whilst sprint running induced fatigue led to a eccentric specific reduction in knee flexor torque, MPF was suppressed across both contraction modes. This would indicate that factors associated with the decline in MPF do not appear to explain the contraction mode-specific loss of strength after intermittent sprints. This would implicate other central mechanisms, such as declines in voluntary activation, in explaining the eccentric specific decline in strength seen following sprint running.
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Background: Greater research utilisation in cancer nursing practice is needed, in order to provide well-informed and effective nursing care to people affected by cancer. This paper aims to report on the implementation of evidence-based practice in a tertiary cancer centre. Methods: Using a case report design, this paper reports on the use of the Collaborative Model for Evidence Based Practice (CMEBP) in an Australian tertiary cancer centre. The clinical case is the uptake of routine application of chlorhexidine-impregnated sponge dressings for preventing centrally inserted catheter-related bloodstream infections. In this case report, a number of processes that resulted in a service-wide practice change are described. Results: This model was considered a feasible method for successful research utilisation. In this case report, chlorhexidine-impregnated sponge dressings were proposed and implemented in the tertiary cancer centre with an aim of reducing the incidence of centrally inserted catheter-related bloodstream infections and potentially improving patient health outcomes. Conclusion: The CMEBP is feasible and effective for implementing clinical evidence into cancer nursing practice. Cancer nurses and health administrators need to ensure a supportive infrastructure and environment for clinical inquiry and research utilisation exists, in order to enable successful implementation of evidence-based practice in their cancer centres.
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The study presented in this paper reviewed 9,358 accidents which occurred in the U.S. construction industry between 2002 and 2011, in order to understand the relationships between the risk factors and injury severity (e.g. fatalities, hospitalized injuries, or non-hospitalized injuries) and to develop a strategic prevention plan to reduce the likelihood of fatalities where an accident is unavoidable. The study specifically aims to: (1) verify the relationships among risk factors, accident types, and injury severity, (2) determine significant risk factors associated with each accident type that are highly correlated to injury severity, and (3) analyze the impact of the identified key factors on accident and fatality occurrence. The analysis results explained that safety managers’ roles are critical to reducing human-related risks—particularly misjudgement of hazardous situations—through safety training and education, appropriate use of safety devices and proper safety inspection. However, for environment-related factors, the dominant risk factors were different depending on the different accident types. The outcomes of this study will assist safety managers to understand the nature of construction accidents and plan for strategic risk mitigation by prioritizing high frequency risk factors to effectively control accident occurrence and manage the likelihood of fatal injuries on construction sites.
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Objectives: To compare measures of fat-free mass (FFM) by three different bioelectrical impedance analysis (BIA) devices and to assess the agreement between three different equations validated in older adult and/or overweight populations. Design: Cross-sectional study. Setting: Orthopaedics ward of Brisbane public hospital, Australia. Participants: Twenty-two overweight, older Australians (72 yr ± 6.4, BMI 34 kg/m2 ± 5.5) with knee osteoarthritis. Measurements: Body composition was measured using three BIA devices: Tanita 300-GS (foot-to-foot), Impedimed DF50 (hand-to-foot) and Impedimed SFB7 (bioelectrical impedance spectroscopy (BIS)). Three equations for predicting FFM were selected based on their ability to be applied to an older adult and/ or overweight population. Impedance values were extracted from the hand-to-foot BIA device and included in the equations to estimate FFM. Results: The mean FFM measured by BIS (57.6 kg ± 9.1) differed significantly from those measured by foot-to-foot (54.6 kg ± 8.7) and hand-to-foot BIA (53.2 kg ± 10.5) (P < 0.001). The mean ± SD FFM predicted by three equations using raw data from hand-to-foot BIA were 54.7 kg ± 8.9, 54.7 kg ± 7.9 and 52.9 kg ± 11.05 respectively. These results did not differ from the FFM predicted by the hand-to-foot device (F = 2.66, P = 0.118). Conclusions: Our results suggest that foot-to-foot and hand-to-foot BIA may be used interchangeably in overweight older adults at the group level but due to the large limits of agreement may lead to unacceptable error in individuals. There was no difference between the three prediction equations however these results should be confirmed within a larger sample and against a reference standard.
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The selection of appropriate analogue materials is a central consideration in the design of realistic physical models. We investigate the rheology of highly-filled silicone polymers in order to find materials with a power-law strain-rate softening rheology suitable for modelling rock deformation by dislocation creep and report the rheological properties of the materials as functions of the filler content. The mixtures exhibit strain-rate softening behaviour but with increasing amounts of filler become strain-dependent. For the strain-independent viscous materials, flow laws are presented while for strain-dependent materials the relative importance of strain and strain rate softening/hardening is reported. If the stress or strain rate is above a threshold value some highly-filled silicone polymers may be considered linear visco-elastic (strain independent) and power-law strain-rate softening. The power-law exponent can be raised from 1 to ~3 by using mixtures of high-viscosity silicone and plasticine. However, the need for high shear strain rates to obtain the power-law rheology imposes some restrictions on the usage of such materials for geodynamic modelling. Two simple shear experiments are presented that use Newtonian and power-law strain-rate softening materials. The results demonstrate how materials with power-law rheology result in better strain localization in analogue experiments.