1,720,961 research outputs found
Digital filtering for power systems distance protection using Walsh functions
No full textDistance relays must estimate accurately and quickly the distance to the fault even in presence of highly distorted input signals. Several digital filtering algorithms for distance relays have been proposed and some of them are used in practical applications. However nonlinear loads are becoming more and more common in electric power systems and that increases the corruption level of signals. For this reason, the study of digital filtering techniques for the extraction of fundamental components from highly corrupt voltage and current waveforms is of vital importance for the development of algorithms applied to the digital protection of transmission lines. The studied technique proposed in this paper is based on Walsh functions
Instantaneous average active power measurement for building energy management system
No full textFast and accurate measurement of the instantaneous average active power is useful for building Energy Management System (EMS) in order to assure quality of service such as continuity, optimize energy consumption and reduce carbon dioxide emission.
In this paper the problems connected to the measurement of the instantaneous average active power for energy usage improving are discussed, also as the operational processes which deal to solve such problems
Rational building energy consumption by advanced control technologies based on instantaneous average active power measurement
No full textFast and accurate measurement of the instantaneous average active power (IAAP) is useful for building Energy Management System (EMS) in order to assure quality of service such as continuity, optimize energy consumption and reduce carbon dioxide emission. In this paper the problems connected to the measurement of the instantaneous average active power for energy usage improving are discussed, also as the operational processes which deal to solve such problems
Digital fault location estimator for power lines based on Walsh functions
No full textDistance relays must estimate accurately and quickly the distance to the fault even in presence of highly distorted input signals. Several digital filtering algorithms for distance relays have been proposed and some of them are used in practical applications. However nonlinear loads are becoming more and more common in electric power systems and that increases the corruption level of signals. For this reason, the study of digital filtering techniques for the extraction of fundamental components from highly corrupt voltage and current waveforms is of vital importance for the development of algorithms applied to the digital protection of transmission lines. The studied technique proposed in this paper is based on Walsh functions
Analysis and measurement of permittivity in composite materials at low frequencies
No full textThis paper focuses on the measurement of the effective permittivity εeff in composite structures. A reconsideration of some concepts related to the measurement of effective permittivity for dielectric media and compositematerials at low frequencies is discussed. In particular, the possibility to measure the average electric displacement and electric field over a region of interest on the basis of the circulation law of the magnetic field by the use of properly shaped Rogowski coils is analyzed. A three-dimensional finite element analysis is carried out to simulate the effective magnetic permeability of a composite materials with the aim to find analogy between the two macroscopic electromagnetic parameters
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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