Papers by Angelo Cesar Colombini
Proposal for Improving Power Quality in Brazilian Navy Ships through the Application of Shunt Active Power Filters (SAPF)
Journal of Engineering Science and Technology Review
Engevista, 2017
Os avanços obtidos com sistemas eletrônicos aplicados em estabilizadores de tensão são grandes. E... more Os avanços obtidos com sistemas eletrônicos aplicados em estabilizadores de tensão são grandes. Este artigo objetiva comparar o desempenho de três modelos de estabilizadores de tensão comercializados no mercado brasileiro enfatizando o aspecto de qualidade de energia, em especial avaliando os distúrbios (distorções) que estes equipamentos podem introduzir na rede de energia elétrica. As avaliações foram executadas em laboratório da Universidade Federal Fluminense (UFF) com qualimetros certificados. As grandezas elétricas analisadas foram: tensão, corrente e distorções harmônicas, comprovando que os sistemas eletrônicos mais modernos reduzem as distorções na rede e alimentam as cargas com energia de melhor qualidade comparada com os estabilizadores mais antigos.
Arquitetura para Transformada de Distância e sua aplicação para o cálculo da Dimensão Fractal
Distance Transform is an important tool for digital imaging processing. Using the Distance Transf... more Distance Transform is an important tool for digital imaging processing. Using the Distance Transform it is possible to evaluate the fractal dimension of objects. Fractal dimension is very important in shape analysis and patter n recognition operations. Few are the hardware implementation for these operations. In this work we present a parallel implementation based on the exact dilation for the evaluation of the Distance Transform and Fractal Dimension .
Arquitetura para Transformada de Distância
Distance Transform is an important tool for digital imaging processing. Using the Distance Transf... more Distance Transform is an important tool for digital imaging processing. Using the Distance Transform it is possible to evaluate very important process in shape analysis and pattern recognition operations. Few are the hardware implementation for these operations. In this work we present a parallel implementation based on the exact dilation for the evaluation of the Distance Transform.
ITEGAM- Journal of Engineering and Technology for Industrial Applications (ITEGAM-JETIA), 2020
One of the great challenges to obtaining knowledge from data sources is to ensure consistency and... more One of the great challenges to obtaining knowledge from data sources is to ensure consistency and non-duplication of stored information. Many techniques have been proposed to minimize the work cost and to allow data to be analyzed and properly corrected. However, there are still other essential aspects for the success of data cleaning process that involve many technological areas: performance, semantic and autonomy of the process. Against this backdrop, we developed an automated configurable data cleaning environment based on training and physical-semantic data similarity, aiming to provide a more efficient and extensible tool for performing information correction which covers problems not yet explored such as semantic and autonomy of the cleaning implementation process. The developed work has, among its objectives, the reduction of user interaction in the process of analyzing and correcting data inconsistencies and duplications. With a properly calibrated environment, the efficiency is significant, covering approximately 90% of inconsistencies in the database, with a 0% percentage of false-positive cases. Approaches were also demonstrated to show that besides detecting and treating information inconsistencies and duplication of positive cases, they also addressed cases of detected false-positives and the negative impacts they may have on the data cleaning process, whether manual or automated, which is not yet widely discussed in literature. The most significant contribution of this work refers to the developed tool that, without user interaction, is automatically able to analyze and eliminate 90% of the inconsistencies and duplications of information contained in a database, with no occurrence of false-positives. The results of the tests proved the effectiveness of all the developed features, relevant to each module of the proposed architecture. In several scenarios the experiments demonstrated the effectiveness of the tool.
Recommissioning methodology for the evaluation of airport air conditioning systems
Proceedings of the Institution of Civil Engineers - Energy
The commissioning processes of new buildings, existing buildings and continuous commissioning hav... more The commissioning processes of new buildings, existing buildings and continuous commissioning have been important tools to identify low performance and high energy consumption problems, contributing to its solutions, energy conservation and the research of more efficient systems. Considering the important participation of air conditioning systems in the energy consumption of buildings, this article presents the proposed methodology in study based on the recommissioning concepts to evaluate the operational and energy performance of these systems. The methodology is demonstrated through its application at an airport air conditioning system in the city of Rio de Janeiro. The operational data collected daily are used to demonstrate the phases of the proposed methodology. The evaluation of the system was performed by the process capability analysis, operational mode in use and performance coefficient (COP). As result, improvement opportunities were identified, with COP growth from 5.95 t...
Proteção Diferencial De Linhas - Uma Abordagem Usando Sampled Values
Engenharia Elétrica: Desenvolvimento e Inovação Tecnológica, 2021
An Efficient Parallel Optimization for Co-Authorship Network Analysis
2017 18th International Conference on Parallel and Distributed Computing, Applications and Technologies (PDCAT), 2017
Co-authorship analysis in science and technology partnerships provides a vision of cooperation pa... more Co-authorship analysis in science and technology partnerships provides a vision of cooperation patterns between individuals and organizations and is still widely used to understand and assess scientific collaboration patterns. This analysis is conducted by means of bibliometry, which is the quantitative study of scientific production. However, with the evolution of database management systems, there was a significant increase in the volume of stored data, which could difficult the analysis. In this context, the developed work presents an efficient parallel optimization of bibliometric information, in order to allow this scientific analysis in a Big Data environment. Our results show that the time taken to calculate the transitivity value using the sequential approach grows 4.08 times faster than the parallel proposed approach when the number of nodes tends to infinity; the time taken to calculate the average distance and diameter values using the sequential approach grows 5.27 times faster than the parallel proposed approach when the number of nodes tends to infinity. Also, the results found present good values of speed up and efficiency.
A Configurable Strategy for Extraction, Transformation and Load to Support Data Propagation on Active Data Warehouses
2016 17th International Conference on Parallel and Distributed Computing, Applications and Technologies (PDCAT), 2016
This work consists of the construction of a strategy called ETL-PoCon to execute Extraction, Tran... more This work consists of the construction of a strategy called ETL-PoCon to execute Extraction, Transformation and Load (ETL) processes in active Data Warehouses (DW) with a configurable policy. The original contribution of this work is to provide a strategy that considerably reduces the quantity of data transfers to active DW, besides maintaining a satisfactory level of data freshness. Said reduction is obtained by means of configurable policies of data propagation based on relevance of the data regarding to the information stored in the DW. The strategy was implemented in a database related to health worker that contains more than seventy thousand records of occupational accidents. Experiments have shown that the ETL-PoCon strategy significantly contributes towards a reduction of the overload on the systems involved in the active DW environment, since all results presented a reduction higher than 60% in the amount of DW refreshments.
Latência Na Comunicação Para Esquemas De Teleproteção: Requisitos, Avaliações e Meios De Transmissão
Energies, 2021
This paper presents a big data analytics-based model developed for electric distribution utilitie... more This paper presents a big data analytics-based model developed for electric distribution utilities aiming to forecast the demand of service orders (SOs) on a spatio-temporal basis. Being fed by robust history and location data from a database provided by an energy utility that is using this innovative system, the algorithm automatically forecasts the number of SOs that will need to be executed in each location in several time steps (hourly, monthly and yearly basis). The forecasted emergency SOs demand, which is related to energy outages, are stochastically distributed, projecting the impacted consumers and its individual interruption indexes. This spatio-temporal forecasting is the main input for a web-based platform for optimal bases allocation, field team sizing and scheduling implemented in the eleven distribution utilities of Energisa group in Brazil.
Analysis of electrical and luminotechnical parameters in led lamps considering Brazilian standards
International Journal of Emerging Electric Power Systems, 2020
The consumption of electric energy in Brazil in 2018 was 472 GWh, and 28.85% of consumption refer... more The consumption of electric energy in Brazil in 2018 was 472 GWh, and 28.85% of consumption refers to the residential sector. The Brazilian market for Light Emitting Diode (LED) products grows more than 30% a year, while LED imports have grown from 131 million units in 2015 to 145 million in 2017 (+10.6%). Therefore, the need to improve the technical and conformity assessment requirements for LED bulbs sold in Brazil is evident. This work analyses Electrical and Luminotechnical Parameters in LED lamps considering Brazilian standards analysing some parameters of LED lamps, which employ different topologies in their drivers, when submitted to voltage magnitude variation. Samples are tested on 18 single-base LED lamps with an integrated control device, GLS LED bulbs, available at the Brazilian market. The methodology consists in applying nominals voltages as INMETRO standards determinates. Throughout the tests, measurements are done and compared with the levels established by Brazilian...
CHSMST+: An Algorithm for Spatial Clustering
2016 17th International Conference on Parallel and Distributed Computing, Applications and Technologies (PDCAT), 2016
Spatial clustering has been widely studied due to its application in several areas. However, the ... more Spatial clustering has been widely studied due to its application in several areas. However, the algorithms of such technique still need to overcome several challenges to achieve satisfactory results on a timely basis. This work presents an algorithm for spatial clustering based on CHSMST, which allows: data clustering considering both distance and similarity, enabling to correlate spatial and nonspatial data, user interaction is not necessary, and use of multithreading technique to improve the performance. The algorithm was tested ia a real database of health area.
Differential protection presents a great sensibility when it comes to isolating equipment under f... more Differential protection presents a great sensibility when it comes to isolating equipment under fault conditions. With the arrival of IEC 61850 standard, the use o nonconventional instrument transformers, and the need for a communication network to perform the exchange of messages inside and in between substations, a new horizon has been presented to protection engineers with new opportunities emerging. This paper proposes the o use o Sampled Value messages – IEC 61850 standard – to use it on differential protection for transmission lines. A feasibility study for the use of differential protection is carried out on two 500 kV transmission lines belonging to the company TAESA, through the Aspen Oneliner software. The communication network to support the proposal has also been evaluated with switches utilized in substations. The results indicate that the solution is feasible; however, the communication network’s simplicity is essential to achieve a balance between speed and resilience...
CHSMST plus : An Algorithm for Spatial Clustering
This paper presents main communication requirements on teleprotection implementation and a study ... more This paper presents main communication requirements on teleprotection implementation and a study comparing different communication media used in these systems, based on state of art. After the requirements survey, it was identified the need to evaluate the media latency over teleprotection time restrictions, specially when network traffic competes with other services as video and voice streaming, or supervisory and control systems. This study also compares traditional teleprotection scenario with new communication networking scenario. The signals propagation achieved times were higher over the network media than the scenario with copper pilot wire cable as evaluated. There’s a gradual impact on the teleprotection signals latency when the concurrent network traffic increases.
Revista Augustus, 2020
Os sistemas de teleproteção tem sido modernizados com a inserção de novas tecnologias de telecomu... more Os sistemas de teleproteção tem sido modernizados com a inserção de novas tecnologias de telecomunicações. Sistemas mais confiáveis com menor tempo de resposta estão sendo testados e aplicados às linhas de transmissão. Este trabalho apresenta uma revisão tema destacado, abordando aspectos do sistema de transmissão, equipamentos, funções de proteção aplicáveis e sistemas de telecomunicações, detalhando aspectos técnicos e apresentando uma avaliação comparativa entre tecnologias.
Acta Polytechnica, 2021
This paper introduces a methodology for modelling a digital admittance-type distance relay using ... more This paper introduces a methodology for modelling a digital admittance-type distance relay using PSCAD/EMTDC. The proposed distance relay was tested in a simulation of the Brazilian power grid with predetermined fault scenarios. The goal of this paper is to make a detailed evaluation of the mho distance relay. The main aspects include the correct operation of the distance relay, fault resistance effects on the mho characteristics, and the fault detection time of this relay. A new approach to analyse the fault detection time is presented, considering several simulated fault scenarios. The results demonstrate that the fault resistance influences the fault detection time and severely affects the distance relay’s general performance. The fault detection time is not constant. It varies within a time interval, considering different fault types, fault locations, and fault resistances. The confidence interval calculation provides a detailed range of the fault detection time, considering its...
International Journal of Computational Science and Engineering, 2020
Bibliometry is the quantitative study of scientific productions and enables the characterisation ... more Bibliometry is the quantitative study of scientific productions and enables the characterisation of scientific collaboration networks. However, with the development of science and the increase of scientific production, large collaborative networks are formed, which makes it difficult to extract bibliometrics. In this context, this work presents an efficient parallel optimisation of three bibliometrics for co-authorship network analysis using multithread programming: transitivity, average distance, and diameter. Our experiments found that the time taken to calculate the transitivity value using the sequential approach grows 4.08 times faster than the parallel proposed approach when the size of co-authorship network grows. Similarly, the time taken to calculate the average distance and diameter values using the sequential approach grows 5.27 times faster than the parallel proposed approach when the size of co-authorship network grows. In addition, we report relevant values of speed up and efficiency for the developed algorithms.
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Papers by Angelo Cesar Colombini