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Flávio Murilo Pereira da Costa

Bio: Flávio Murilo Pereira da Costa is an academic researcher from University of Brasília. The author has contributed to research in topics: Busbar & Emtp. The author has an hindex of 3, co-authored 9 publications receiving 44 citations. Previous affiliations of Flávio Murilo Pereira da Costa include Federal University of Rio Grande do Norte.

Papers
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Journal ArticleDOI
TL;DR: The obtained results reveal the proposed 87BW function provides ultra-high-fast trip for internal and evolving external-to-internal faults, guaranteeing security for normal through-load and external faults as well, even in the case of early and severe current transformer (CT) saturation.
Abstract: This paper presents a new wavelet-based busbar differential protection algorithm, named as 87BW function. The instantaneous current-based differential protection fundamentals are taken into account and the well-known 1-out-of-1 and 2-out-of-2 tripping logics are mapped into the wavelet domain. Operating and restraint wavelet coefficients energy of currents are computed, regarding station configuration and bus zones boundaries. Thereby, the proposed 87BW function can be properly used in both static and dynamic busbar configuration. Its performance was evaluated through EMTP-based simulations of faults in a 230 kV power substation with double bus single breaker configuration. The obtained results reveal it provides ultra-high-fast trip for internal and evolving external-to-internal faults, guaranteeing security for normal through-load and external faults as well, even in the case of early and severe current transformer saturation.

26 citations

Proceedings ArticleDOI
01 Aug 2018
TL;DR: The obtained results reveal the proposed 87BW function provides ultra-high-fast trip for internal and evolving external-to-internal faults, guaranteeing security for normal through-load and external faults as well, even in the case of early and severe current transformer saturation.
Abstract: This paper presents a new wavelet-based busbar differential protection algorithm, named as 87BW function. The instantaneous current-based differential protection fundamentals are taken into account and the well-known 1-out-of-1 and 2-out-of-2 tripping logics are mapped into the wavelet domain. Operating and restraint wavelet coefficients energy of currents are computed, regarding station configuration and bus zones boundaries. Thereby, the proposed 87BW function can be properly used in both static and dynamic busbar configuration. Its performance was evaluated through EMTP-based simulations of faults in a 230 kV power substation with double bus single breaker configuration. The obtained results reveal it provides ultra-high-fast trip for internal and evolving external-to-internal faults, guaranteeing security for normal through-load and external faults as well, even in the case of early and severe current transformer (CT) saturation.

12 citations

16 Jul 2013
TL;DR: In this paper, a presente estudo teve como objetivo identificar os instrumentos de controle e de analise economica-financeira utilizados pelos produtores of graos do municipio de Sao Gabriel do Oeste -Mato Grosso do Sul, assim como a importância dada pelos mesmos a funcao de controLE.
Abstract: As mudancas ocorrentes na economia mundial, particularmente a abertura dos mercados e as novas exigencias dos consumidores, fazem com que o produtor rural necessite aumentar a eficiencia na producao e na gestao das atividades agricolas. Com base nessa premissa, o presente estudo teve como objetivo identificar os instrumentos de controle e de analise economica-financeira utilizados pelos produtores de graos do municipio de Sao Gabriel do Oeste - Mato Grosso do Sul, assim como a importância dada pelos mesmos a funcao de controle. Por meio de questionario aplicado a uma amostra de produtores, foi possivel constatar que ainda existem produtores que nao fazem nenhum tipo de controle. E os que o fazem, nem sempre utilizam esses instrumentos da maneira correta, levando em consideracao apenas alguns componentes do custo total. Alem disso, muitos deles ainda nao utilizam da tecnologia computacional como uma ferramenta de auxilio em suas empresas rurais. Embora a proporcao de produtores que compreende e executa a gestao financeira de maneira correta seja reduzida, existe uma percepcao generalizada sobre a importância de um controle efetivo para facilitar as tomadas de decisao.

4 citations

Book ChapterDOI
13 Oct 2013
TL;DR: A straightforward two-fold unsupervised strategy to extract and tag entities, aiming to achieve accurate results in the identification of proper nouns and concrete concepts, regardless the domain, is described.
Abstract: The WISE 2013 conference proposed a challenge (T1 Track) in which teams must label entities within plain texts based on Wikilinks dataset which comprises 40 million mentions over 3 million existed entities. This paper describe a straightforward two-fold unsupervised strategy to extract and tag entities, aiming to achieve accurate results in the identification of proper nouns and concrete concepts, regardless the domain. The proposed solution is based on a pipeline of text processing modules that includes a lexical parser. The solution labelled 8824 texts, and the results achieved satisfying precision measures.

2 citations


Cited by
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01 Jan 1965
TL;DR: WALLIS ALLEN W. W. E. and ROBERTS V. HARRY as mentioned in this paper have published a survey of the state of the art in the field of finance in Brazil.
Abstract: WALLIS ALLEN W. e ROBERTS V. HARRY. Curso de Estatistica (Trad.). Rio de Janeiro, Missao Norte-Americana de Cooperacao Economica e Tecnica no Brasil e Ed. Fundo de Cultura, 1964, 2 vol, 802 paginas.

100 citations

Journal ArticleDOI
TL;DR: A novel query expansion method for candidate generation utilizing the information of co-occurrences of mentions and a re-ranking model which can be iteratively adjusted based on the prediction in the previous round are proposed.
Abstract: We propose Feedback-query-expansion and Re-ranking methods which model the semantic relatedness of entities in one document.We demonstrate the effectiveness of our methods by comparing with the baseline systems on three data sets.Our team has scored in the top 3 teams across multiple metrics for the English EDL task in TAC2014. Entity disambiguation is a fundamental task of semantic Web annotation. Entity Linking (EL) is an essential procedure in entity disambiguation, which aims to link a mention appearing in a plain text to a structured or semi-structured knowledge base, such as Wikipedia. Existing research on EL usually annotates the mentions in a text one by one and treats entities independent to each other. However this might not be true in many application scenarios. For example, if two mentions appear in one text, they are likely to have certain intrinsic relationships. In this paper, we first propose a novel query expansion method for candidate generation utilizing the information of co-occurrences of mentions. We further propose a re-ranking model which can be iteratively adjusted based on the prediction in the previous round. Experiments on real-world data demonstrate the effectiveness of our proposed methods for entity disambiguation.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a discrete Frechet distance algorithm based criterion of transformer differential protection is proposed to identify the differences of phase characteristics of currents on transformer both sides under various conditions including faults accompanied with CT saturations, transformer ultra-saturation and abnormal samplings.
Abstract: The saturation of current transformers (CTs) has adverse impact on the reliability of the transformer differential protection. However, the overall phase information of currents are less affected by CT saturations. The Frechet distance algorithm, which is provided with the superiorities in the similarity identification, is utilized to acquire the phase information difference between the currents on both sides of the transformer. On this basis, the discrete Frechet distance algorithm based criterion of transformer differential protection is put forward. It can identify the differences of phase characteristics of currents on transformer both sides under various conditions including faults accompanied with CT saturations, transformer ultra-saturation and abnormal samplings. The effectiveness of the proposed criterion were validated respectively with simulation and experiment tests.

24 citations

Journal ArticleDOI
TL;DR: In this article, the authors conducted 55 semi-structured questionnaires in the Western Region of Parana and identified which milk producers do not adopt financial management practices in dairy production systems.
Abstract: The objective of this paper was to analyze financial management practices in dairy production systems. More specifically, we sought to identify which milk producers adopt financial management practices. We conducted 55 semi-structured questionnaires in the Western Region of Parana. The data were processed through descriptive and multivariate statistical analysis. The analysis of hierarchical clusters defined, based on variables related to financial management practices, two distinct groups. The first group included milk producers who do not adopt financial management practices [...]

22 citations

Journal ArticleDOI
TL;DR: The proposed algorithm is twice or more faster than the traditional instantaneous-current-based algorithm for most of the internal and evolving external-to-internal faults, while ensuring secure operation for external ones even when severe current transformer (CT) saturation takes place, through a new harmonic power restraint strategy.
Abstract: This paper presents a new method for busbar differential protection based on the instantaneous power concept. In order to do so, the instantaneous power per phase of each network element connected to the busbar is computed by using the instantaneous current values and a voltage memory action strategy. The performance of the proposed technique is compared to one of the traditional instantaneous-current-based differential protection algorithms, which is widely used by manufacturers of commercial relays. Both internal and external faults, as well as evolving external-to-internal faults, were simulated in a power substation with double-bus single-breaker configuration using the software ATPDraw. The obtained results reveal that the proposed algorithm is twice or more faster than the traditional instantaneous-current-based algorithm for most of the internal and evolving external-to-internal faults, while ensuring secure operation for external ones even when severe current transformer (CT) saturation takes place, through a new harmonic power restraint strategy. Also, since the proposed method provides faster fault detection time, the requirements for CT time to saturate may be alleviated, guaranteeing correct operation even in the case of early CT saturation.

19 citations