Alexandra M. A. C. Pinto

Differential-Evolution-Based Optimization of the Dynamic Response for Parallel Operation of Inverters With No Controller Interconnection

In this paper, the use of differential evolution (DE), a global search technique inspired by evolutionary theory, to find the parameters that are required to achieve optimum dynamic response of parallel operation of inverters with no interconnection among the controllers is proposed. Basically, in order to reach such a goal, the system is modeled in a certain way that the slopes of P- ω and Q -V curves are the parameters to be tuned. Such parameters, when properly tuned, result in systems eigenvalues located in positions that assure the systems stability and oscillation-free dynamic response with minimum settling time. This paper describes the modeling approach and provides an overview of the motivation for the optimization and a description of the DE technique. Simulation and experimental results are also presented, and they show the viability of the proposed method.

Fraud detection in high voltage electricity consumers using data mining

This work presents a methodology and a computational system for fraud detection for high voltage electrical energy consumers using data mining. This methodology is based on a non-supervised artificial neural network called SOM (Self-Organizing Maps), which allows the identification of the consumption profile historically registered for a consumer, and its comparison with present behavior, and shows possible frauds. From the automatic consumer behavior pre-analysis, electrical energy companies will better direct its inspections, and will reach higher rates of correctness. The fraud detection system validation showed that the methodology is robust on the cases of lower consumption resulted by fraud, and on the cases of atypicality intrinsic to the consumer.

Fraud detection system for high and low voltage electricity consumers based on data mining

This work presents two computational system for fraud detection for both high and low voltage electrical energy consumers based on data mining. This two kinds of consumers demanded different approaches and methodologies. The first is based on SOM (Self-Organizing Maps), which allows the identification of the consumption profile historically registered for a consumer, and its comparison with present behavior. The second is based on a hybrid of data mining techniques. From the consumer behavior pre-analysis, electrical energy companies will better direct its inspections and will reach higher rates of correctness. The validation and results showed that the two systems are efficient on the cases of lower consumption resulted by fraud.

Methodology for fraud detection using rough sets

This work proposes a methodology based on Rough Sets and KDD for fraud detection made by electrical energy consumers. This methodology does a detailed evaluation of the boundary region between normal and fraudulent costumers, identifying patterns of fraudulent behavior at historical data sets of electricity companies. Using these patterns, classification rules are derived, and they will permit the detection on the database of electricity companies of those clients that present fraudulent feature. When doing inspections with the proposed methodology, the rate of correctness and the quantity of detected frauds are increased, decreasing the losses with electricity fraud on Brazilian electrical energy distribution companies. One of the problems that Brazilian electrical energy distri- bution companies undergo are the commercial losses resulted from consumers electrical frauds. To decrease these losses, the companies realize in loco inspections to detect such frauds. The inspections are made by technicians that go to the con- sumer unit to evaluate equipments and electricity connections. Usually, company experts indicates which consumer unit must undergo the inspection. This decision is based on factors such as: unit with low consumption rate, high fraud incidence, and others. Since there is a very high number of consumer units, it is almost impossible for the expert to evaluate the behavior of each consumer unit and indicate which ones are suspect of fraud. Also, it is not viable to inspect all the consumer units, seeing that the number of fraudulent consumers is small compared to the total number of consumers. The rate of correct fraud identification of the electrical energy distribution companies goes between 5 to 10%. However, it is known that electrical energy distribution companies keep consumer information on theirs databases. This information can be used for the identification of behavior patterns. When finding a pattern that indicates a fraudulent behavior, the expert can recommend that consumers with this pattern must undergo inspection. The discovery process of these behavior patterns when using databases is called KDD (Knowledge Discovery in Databases) (1). This process

The burden and quality of life of caregivers of sickle cell anemia patients taking hydroxyurea versus those not taking hydroxyurea

OBJECTIVE: To assess the burden and quality of life of caregivers of patients with sickle cell anemia taking hydroxyurea versus those of patients not taking hydroxyurea. METHODS: A cross-sectional study was performed of caregivers of outpatients with sickle cell anemia in two public hospitals in Campo Grande, MS, from January through June 2010. The World Health Organization Quality of Life-BREF Scale and the Caregiver Burden Scale were used. RESULTS: Of the 37 caregivers in this study, 81.1% were women, 73.0% were mothers, 59.5% were married, 54.1%were mulattos, 48.6% were housewives, 54.1% had family incomes of up to one minimum wage and 75.7% had onlycompleted elementary education. The mean duration of care provided (time after diagnosis) was 16.08 ± 9.88 yearsand 89.2% reported that they provided 24-hour care. Regarding health, 27.0% of study participants reported having physical and 13.5% emotional problems. There were no significant relationships between these variables either with the different domains or the total score of the WHOQOL-BREF comparing caregivers of patients taking hydroxyurea versusthose of patients not taking hydroxyurea. There was a moderate negative linear correlation between the WHOQOL-BREF and the Caregiver Burden Scale scores (linear correlation test of Pearson: p-value = 0.003, r = -0.477). The burden of caregivers of patients who did not take hydroxyurea was significantly higher than those of patients who took the medication in terms of general tension, disappointment, environment and total score (student t-test: p-value < 0.05). CONCLUSION: In the perception of the caregiver, looking after sickle cell anemia patients represents a moderate negative burden.Objective To assess the burden and quality of life of caregivers of patients with sickle cell anemia taking hydroxyurea versus those of patients not taking hydroxyurea. Methods A cross-sectional study was performed of caregivers of outpatients with sickle cell anemia in two public hospitals in Campo Grande, MS, from January through June 2010. The World Health Organization Quality of Life-BREF Scale and the Caregiver Burden Scale were used. Results Of the 37 caregivers in this study, 81.1% were women, 73.0% were mothers, 59.5% were married, 54.1%were mulattos, 48.6% were housewives, 54.1% had family incomes of up to one minimum wage and 75.7% had onlycompleted elementary education. The mean duration of care provided (time after diagnosis) was 16.08 ± 9.88 yearsand 89.2% reported that they provided 24-hour care. Regarding health, 27.0% of study participants reported having physical and 13.5% emotional problems. There were no significant relationships between these variables either with the different domains or the total score of the WHOQOL-BREF comparing caregivers of patients taking hydroxyurea versusthose of patients not taking hydroxyurea. There was a moderate negative linear correlation between the WHOQOL-BREF and the Caregiver Burden Scale scores (linear correlation test of Pearson: p-value = 0.003, r = -0.477). The burden of caregivers of patients who did not take hydroxyurea was significantly higher than those of patients who took the medication in terms of general tension, disappointment, environment and total score (student t-test: p-value < 0.05). Conclusion In the perception of the caregiver, looking after sickle cell anemia patients represents a moderate negative burden.

Modeling and simulation of a supervision and management system of hybrid energy systems for the Pantanal region

This work developed a modeling for simulation of a supervising and management system for hybrid energy systems. The modeling uses many renewable energy sources and a battery bank. The main objective is to attend the demand of the Pantanal Study Base (BEP) of the Federal University of Mato Grosso do Sul only with renewable energy sources. So, scenarios of typical days and one year scenario were developed to verify the behavior of the battery bank. First, hybrid energy systems and renewable energy sources are briefly presented. Then the model is described. Following, how the demand curve was obtained is presented, and the dimensioning of the number of solar panels and the number of batteries of the battery bank. Finally, results obtained with the modeling of the system are presented.

Decision support system for the management of electricity consumption contracts for Smart Grids environment using Differential Evolution and Artificial Neural Network

The objective of this paper is to present a support system to manage electricity consumption contracts for Smart Grid environment. The system modeling uses historical data consumption and energy trading rules to find the optimal contract structure. Focused Time Lagged Feed forward Network was used to model the historical data. The global search tool Differential Evolution was used to find the best contract structure. This paper presents the use of the tool with current Brazilian pricing rules. However, to change the rules for a dynamic scenario of Smart Grid can be easily implemented. The results are satisfactory and indicate the feasibility of the system for different cases.