997 resultados para power definitions


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This paper discusses the utilization of Virtual Instrumentation to the implementation and evaluation of different power definitions, so that classical formulations and new definitions can be compared without the necessity of acquiring different power meters or analyzers. Accordingly, the definitions of IEEE Standard 1459-2000 for the measurement of power quantities under distorted and unbalanced situations, have been digitally implemented. Thus, several power and power factor components related to the decomposition of the measured voltage and current signals have been obtained. The proposed PC-based Virtual Instrument uses a high performance acquisition board and isolated sensors and transducers. All digital algorithms and routines have been implemented by means of a graphical development system. Regarding to the implementation of STD 1459, this paper also proposes several different algorithms to the required decompositions of voltage, current and power components. © 2005 IEEE.

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One of the important issues about using renewable energy is the integration of dispersed generation in the distribution networks. Previous experience has shown that the integration of dispersed generation can improve voltage profile in the network, decrease loss, etc. but can create safety and technical problems as well. This work report the application of the instantaneous space phasors and the instantaneous complex power in observing performances of the distribution networks with dispersed generators in steady state. New IEEE apparent power definition, the so-called Buchholz-Goodhue effective apparent power, as well as new proposed power quality (oscillation) index in the three-phase distribution systems with unbalanced loads and dispersed generators, are applied. Results obtained from several case studies using IEEE 34 nodes test network are presented and discussed. (C) 2006 Elsevier B.V. All rights reserved.

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One of the important issues about using renewable energy is the integration of dispersed generation in the distribution networks. Previous experience has shown that the integration of dispersed generation can improve voltage profile in the network, decrease loss etc. but can create safety and technical problems as well, This work report the application of the instantaneous space phasors and the instantaneous complex power in observing performances of the distribution networks with dispersed generators in steady state. New IEEE apparent power definition, the so called Buccholz-Goodhue apparent power, as well as new proposed power quality (oscillation) index in the three-phase distribution systems with unbalanced loads and dispersed generators, are applied. Results obtained from several case studies using IEEE 34 nodes test network are presented and discussed.

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This paper explains the conceptual design of instrumentation that measures electric quantities defined in the Std. 1459-2000. It is shown how the instantaneous-space-phasor approach, based on alpha, beta, 0 components, can be used to monitor electric energy flow, evaluate the utilization of transmission line, and quantify the level of harmonic pollution injected by nonlinear loads.

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The paper explains the conceptual design of instrumentation that measures electric quantities defined in the trial-use Std. 1459-2000. It is shown how the Instantaneous-Space-Phasor (ISP) approach, based on α, β, 0 components, can be used to monitor electric energy flow, evaluate the utilization of transmission line and quantify the level of harmonic pollution injected by nonlinear loads.

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The concept of ‘power’ can refer to the institutionalised and embodied capacity and right to dominate through a variety of means including ideology, politics, science, religion, class, race, gender and sexuality. Early feminist theorising within the West, for example, conceptualised the structure and nature of power as being connected to male domination and authority within society. Marxists, alternately, argue it is the ruling class that holds power and exercises it as owners of the means of production. In a general sense, we can say that as feminists have tied power to patriarchy and Marxists’ definitions of power have been connected to capitalism. The essays in this section, though, are less concerned with such totalising conceptualisations of power than they are with processes of interpellation or subject creation within dominant or dominating discursive spaces.1 Not power as such, but its many workings and apparatuses.

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The City of Cairo's experienced a major shift in its urban planning attitude and practice since the mid 1970s which mostly validated elements of economic planning while neutralizing its social aspects. This ad hoc approach escalated conflict in planning politics over the control of space between tiers of the planning institution and the locals leading to rigorous planning actions among major stakeholders such as eviction and control of spaces. The article examines how institutional claims over space reassembled alternative definitions of quality of life in one of Cairo's oldest quarters, and how ambitious planning schemes were mostly driven by entrepreneurial rather than societal. Based on first-hand interviews and visuals, the article aims to reveal the local's struggle to survive such interventions with attention to their daily negotiations in place.

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Les études rhétoriques ont documenté la pertinence de la rhétorique présidentielle et le pouvoir du président de définir les enjeux publics par le discours. Cette recherche porte sur les pratiques rhétoriques par lesquelles l'ancien président mexicain Calderón a défini la lutte contre la drogue qui a caractérisé son administration. Je soutiens que Calderón a avancé une définition du problème de la drogue par des pratiques de définition telles que l'association, la dissociation et les symboles de condensation. Mon analyse 1) identifie les pratiques rhétoriques de définition qui ont caractérisé la lutte à la drogue de Calderón; 2) examine les implications de ces pratiques; et 3) aborde les limites auxquelles les politiciens font face en tentant de modifier des définitions préalablement avancées. En conclusion, j’explique comment les métaphores et les pratiques de définition de Calderón ont ouvert un espace rhétorique où les droits humains pouvaient être révoqués et la violence encouragée.

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Like any form of human interaction and communication it is possible to view Social Media as a means for the powerful to influence and control the less powerful. But what is power on social media, how might we measure or affect it, and does it translate to the real world? In this lecture we will look at the philosophical definitions of power, and explore how it has been analysed in social networks and social media systems. We will also look at the characteristics of social networks that impact on power, including Homophily, Heterophily, CyberBalkanization and Thresholds of Collective Action. Finally we will ask what evidence there is that power in social media can affect what goes on in the real world, and explore some real and fictional examples of protest to see what the consequences of social media actually are on sometimes violent political debate.

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En el actual contexto de globalización y con el comienzo de la era de la información, cada vez más Estados han buscado proyectar una imagen favorable con el objetivo de atraer atención y crear una reputación que permitan cumplir objetivos de política exterior y fomentar el desarrollo económico, logrando de esta manera un posicionamiento en el sistema internacional mediante estrategias novedosas, que incluyen elementos tanto diplomáticos, políticos, económicos, como comerciales y culturales. Para Japón, Nation Branding y la diplomacia pública han sido dos de las principales herramientas para lograr este reposicionamiento internacional, resaltando atractivos como las tradiciones culturales, el turismo, los incentivos para negocios, y trabajando en conjunto entre el gobierno nacional, el sector privado y la sociedad civil para crear relaciones entre el país y gobiernos y sociedades a nivel internacional.

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This paper presents some definitions and concepts of the Instantaneous Complex Power Theory [1] which is a new approach for the Akagi's Instantaneous Reactive Power Theory [2].The powers received by an ideal inductor are interpreted and the knowledge of the actual nature of these powers may lead to changes of the conventional electrical power concepts.

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Considering different single and multiphase circuits feeding linear and non-linear loads, this paper presents theoretical discussions and experimental evaluation of the recent Conservative Power Theory (CPT), by means of Virtual Instrumentation concepts. The main goal is to analyze the results of such power theory definitions under nonsinusoidal and unbalanced conditions, pointing out its major advantages, possible drawbacks or relevant aspects for discussion. © 2009 IEEE.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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OBJECTIVE: To assess the intra-reader and inter-reader reliabilities of interpreting ultrasonography by several experts using video clips. METHOD: 99 video clips of healthy and rheumatic joints were recorded and delivered to 17 physician sonographers in two rounds. The intra-reader and inter-reader reliabilities of interpreting the ultrasound results were calculated using a dichotomous system (normal/abnormal) and a graded semiquantitative scoring system. RESULTS: The video reading method worked well. 70% of the readers could classify at least 70% of the cases correctly as normal or abnormal. The distribution of readers answering correctly was wide. The most difficult joints to assess were the elbow, wrist, metacarpophalangeal (MCP) and knee joints. The intra-reader and inter-reader agreements on interpreting dynamic ultrasound images as normal or abnormal, as well as detecting and scoring a Doppler signal were moderate to good (kappa = 0.52-0.82). CONCLUSIONS: Dynamic image assessment (video clips) can be used as an alternative method in ultrasonography reliability studies. The intra-reader and inter-reader reliabilities of ultrasonography in dynamic image reading are acceptable, but more definitions and training are needed to improve sonographic reproducibility.

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This paper seeks to characterise the gendered and sexualised power relations of both female and male strip clubs, and to signal what this means for establishing positive definitions of female desire. It is argued that while it is not useful to present female strippers, or female patrons of male strip clubs as purely passive victims of male heterosexism within these venues, it is equally damaging to assume that these venues represent a whole-scale challenge to conventional oppressive gender and sexual relations for women. Some research has even suggested that both strippers and their patrons are engaged in a 'mutually exploitative' power relationship. Moreover, further empirical research documents key points where female dancers have perhaps wielded 'more' power over patrons at certain moments, and female dancers have highlighted feelings of empowerment and highlighted potential for gender and sexual relations which position women as passive to be subverted within stripping. However, such feelings are often temporally specific and are not applicable to all women in the strip industry. It may be particularly hard for these to manifest in women concentrated in the least economically-rewarding areas of the industry who have less 'power' to resist compromising their bodily boundaries. Furthermore, it is argued that women watching male strippers does little to reverse the 'male gaze', and nor does this male occupation carry as much negative social stigma with it as female stripping suffers. It is thus argued that the overwhelming picture, stemming largely from accounts of former dancers and from empirical studies of individual clubs, suggests these venues in fact do very little to challenge normative hetero-oppressive sexual scripts.