1,721,315 research outputs found
Medidor de grandezas elétricas com acesso remoto
Get PDFO alto custo de energia elétrica devido a geração, distribuição e taxas e impostos traz um oneroso valor
a renda de várias famílias, sendo necessário uma maior quantidade informações sobre o consumo de eletricidade
de cada aparelho bem como de uma residência inteira. Atualmente existe no mercado aparelhos para medição,
registro e analise de grandezas elétricas, porém alguns são caros e complexos para serem usados por consumidores
comuns. O objetivo do presente trabalho e a criação de um protótipo para o registro e monitoramento de grandezas
elétricas, destinado a implementação na área residencial, utilizando recursos de baixo custo e material de fácil
acesso. O projeto é baseado em um módulo PZEM-004T v3 com capacidade de até 100A, usando como sensor
não invasivo um transformador de corrente, chip de medição de energia elétrica V9881d e uma placa de
desenvolvimento ESPDUINO32 Dl R32 para recuperar dados dos sensores que serão enviados ao servidor via
internet podendo ser acessado por computadores ou Smartfones. Assim o sistema de monitoramento de energia
desenvolvido pode registrar a tensão, corrente, potência ativa, reativa, aparente, fator de potência e consumo
acumulado de energia. Após a construção do protótipo, várias medidas foram efetuadas para a comprovação da
viabilidade da sua utilização na área residencial, porém que não foi possível avaliar o erro percentual de energia
consumida por falta de equipamento adequado. Os testes tiveram como intuito mostrar o possível uso do aparelho
como instrumento de medição.Trabalho não financiado por agência de fomento, ou autofinanciad
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Controle secundário aliado ao corte de carga para microrredes em condições operativas de ilhamento
Get PDFThe evolution of current electrical systems is notorious when compared in the last years.
This evolution is mainly due to the emergence of the smart-grids concept, giving increased
access to the penetration of distributed resources at the level of energy distribution. In this
context, microgrids are increasingly emerging as a potential solution to combine reliability,
quality, and sustainability in the supply of electricity. Since there is a possibility of a microgrid
operates in isolation from the main network, special attention should be given to this issue. In
this way, the MGCC plays a vital role in the survival of the system, managing all the resources
of the agents to guarantee safe operation and within the standards of supply demanded by the
regulatory agencies.
In this Ph.D. thesis, the whole theoretical basis of microgrids is presented, giving
evidence mainly to the problem of islanding regarding the variation of demand, which in many
cases, can cause a point of operation unfeasible due to the inherent variability of demand. To
correct the operation, a unified secondary voltage and frequency control strategy in the process
of power flow convergence is proposed. In addition, taking into account the limitation of the
available resources, the load shedding becomes an emergency approach, preserving the
operation limits and the continuity in the supply of electricity to essential services. Finally, an
analysis within the concept of voltage stability is also presented with the purpose of assisting
in decision making. This analysis shows the relation of the degree of system supportability
related to the converters operation mode and their generation limits, both in the connected and
islanded systems operation.
The results from the tools proposed here are validated and discussed based on the IEEE
37-Nodes Test Feeder system, when modifications are made to make it equivalent to a micro
network.
Thus, in an islanding scenario, it is expected that MGCC with the tools developed here
will be to manage all resources by predicting demand variability and before the system
experiences any non-feasible operating point, regardless of the load and penetration scenario.
renewable resourcesÉ notória a evolução dos sistemas elétricos atuais quando comparado aos dos últimos
anos. Tal evolução deve-se principalmente ao surgimento do conceito de smart-grids, dando
cada vez mais abertura à penetração de recursos distribuídos ao nível de distribuição de energia.
Nesse contexto, as microrredes vêm surgindo como uma potencial solução para aliar
confiabilidade, qualidade e sustentabilidade no fornecimento de energia elétrica. Dada a
possibilidade de uma microrrede operar de forma isolada da rede principal, especial atenção
deve ser dada a esse quesito. Portanto, o MicroGrid Central Controller (MGCC) exerce papel
fundamental na sobrevivência do sistema, gerenciando todos os recursos e agentes de modo a
garantir uma operação segura e dentro dos padrões de fornecimento exigidos pelas agências
regulatórias.
Nesta tese de doutorado, toda a fundamentação teórica de microrredes é apresentada,
dando evidência principalmente ao problema do ilhamento quanto à variação de demanda, o
que em muitos casos, pode ocasionar um ponto de operação não factível. No intuito de corrigir
a operação, uma estratégia de controle secundário unificado de tensão e frequência no processo
de convergência do fluxo de potência é proposta. Ainda, prevendo a limitação dos recursos
disponíveis, o corte de carga se torna uma medida emergencial, levando em consideração para
isso os limites operativos e a continuidade no suprimento de energia elétrica a serviços
essenciais. Por fim, uma análise dentro do conceito de estabilidade de tensão também é
apresentada com o intuito de auxiliar em uma tomada de decisão. Tal análise mostra a relação
do grau de suportabilidade do sistema com o modo operativo dos conversores e seus limites de
geração, tanto para a operação conectada quanto ilhada.
Os resultados provenientes das ferramentas aqui propostas são validados e discutidos
tendo como base o sistema IEEE 37-Nodes Test Feeder, quando modificações são feitas de
modo a torná-lo equivalente a uma microrrede.
Assim, espera-se que em um cenário de ilhamento, o MGCC com as ferramentas aqui
desenvolvidas seja capaz de gerenciar os recursos prevendo a variabilidade da demanda e antes
que o sistema experimente qualquer ponto operativo não factível, independente do cenário de
carga e penetração de recursos renováveis
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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