Contexto: En este trabajo se investiga el uso de un Algoritmo Genético (GA) para la conformación del haz de un arreglo de antenas en ambientes de Acceso Múltiple por División de Código (CDMA) bajo diferentes relaciones SeËœnal a Ruido, asumiendo que la seËœnal de referencia es conocida. Método: El Algoritmo Genético es un método inspirado en principios evolutivos, usado para optimizar una función objetivo seleccionando los mejores candidatos de una población. La población es generada aleatoriamente para asegurar alta diversidad y conseguir una optimación global. Por otro lado, el algoritmo LMS es un algoritmo que garantiza la convergencia siempre y cuando la seËœnal de referencia sea conocida. Resultados: El GA converge más rápidamente en que el algoritmo LMS en todos los escenarios probados. Además, el GA consiguió mejores resultados apuntando el haz para fuentes estáticas descorrelacionadas. Adicionalmente, una apropiada selección de los parámetros del GA permite una mayor velocidad de convergencia y un mejorado rastreamiento de fuentes en movimiento. Conclusiones: Los resultados de las simulaciones confirman que el GA es una herramienta capaz de obtener una convergencia y precisión en la conformación del haz y el rastreamiento de fuentes en movimiento dada una seËœnal de referencia. Por lo tanto, el GA resulta prometedor para sustituir el algoritmo LMS en sistemas de antenas inteligentes y aumentar la capacidad del canal.

Context: This works investigates the use of Genetic Algorithm (GA) for beamforming on a Code Division Multiple Access (CDMA) environment under different Signal-to-Noise Ratios (SNR), assuming a reference signal is known. Method: The GA is a method inspired in evolutionary principles to optimize an objective function by choosing the best candidates of a population. The population is randomly generated to ensure high diversity and get a global optimization. On the other hand, the Least Means squares (LMS) algorithm is an adaptive algorithm with guaranteed convergence as long as a reference signal is known. Results: The GA converged faster than the LMS in all tested scenarios. Besides, GA achieved best results in pointing the beam for uncorrelated static sources. Additionally, proper tuning of GA parameters allowed fast convergence and improved tracking of moving targets. Conclusions: The simulation results confirm that the GA is able to obtain a convergent and accurate tool for beamforming and tracking of moving targets, given a reference signal. Hence, GA turns to be promising in replacing LMS on Smart Antenna Systems for increasing channel capacity.

Abstract Introduction: Due to the increasing popularization of computers and the internet expansion, Alternative and Augmentative Communication technologies have been employed to restore the ability to communicate of people with aphasia and tetraplegia. Virtual keyboards are one of the most primitive mechanisms for alternatively entering text and play a very important role in accomplishing this task. However, the text entry for this kind of keyboard is much slower than entering information through their physical counterparts. Many techniques and layouts have been proposed to improve the typing performance of virtual keyboards, each one concerning a different issue or solving a specific problem. However, not all of them are suitable to assist seriously people with motor impairment. Methods: In order to develop an assistive virtual keyboard with improved typing performance, we performed a systematic review on scientific databases. Results: We found 250 related papers and 52 of them were selected to compose. After that, we identified eight essentials virtual keyboard features, five methods to optimize data entry performance and five metrics to assess typing performance. Conclusion: Based on this review, we introduce a concept of an assistive, optimized, compact and adaptive virtual keyboard that gathers a set of suitable techniques such as: a new ambiguous keyboard layout, disambiguation algorithms, dynamic scan techniques, static text prediction of letters and words and, finally, the use of phonetic and similarity algorithms to reduce the user's typing error rate.

RESUMO Devido ao atual estado de escassez hídrica na região sudeste do Brasil, resultante não apenas do baixo índice pluviométrico, mas também da gestão ineficiente dos recursos hídricos no país, as companhias de abastecimento vem discutindo soluções para esse problema. Entre as soluções possíveis está a criação de novos reservatórios para o abastecimento público. Nesse sentido, o rio Taquaraçu tem sido alvo de atenção dos gestores municipais e de saneamento da Região Metropolitana de Belo Horizonte por ser um dos rios da Bacia Hidrográfica do rio das Velhas com água de melhor estado qualitativo e quantitativo. Sendo um afluente direto do rio das Velhas aventa-se para a possibilidade que suas águas ajudam a diluir a concentração de poluentes com consequente melhora de sua qualidade de água. Portanto, este trabalho visa avaliar, por meio de testes estatísticos, se o rio Taquaraçu interfere de forma positiva para a melhora da qualidade de água do rio das Velhas. Nas análises foi utilizado o banco de dados do Instituto Mineiro das Águas (IGAM), no período de 1997 a 2015, de pontos localizados no rio Vermelho, no rio Taquaraçu e no rio das Velhas. Foram criados gráficos Box Plots e realizada a Análise de Componentes Principais (PCA) para os períodos denominados de seca e chuva. Os resultados demonstraram, que apesar de receber lançamentos de esgotos de várias cidades do seu entorno, o rio Taquaraçu apresenta boa qualidade de água. Entretanto, os resultados dos PCAs indicaram que o rio Taquaraçu não altera a já atestada má qualidade das águas do rio das Velhas.

ABSTRACT Southeastern Brazil is experiencing severe water scarcity because of low rainfall and inefficient water resource management. As a consequence, water supply companies have begun discussing potential solutions to this problem. One proposed solution is creation of new public water supply reservoirs. Recently, managers from municipalities in the metropolitan region of Belo Horizonte, along with sanitation companies, have begun to focus their attention on the Rio Taquaraçu. The Taquaraçu lies in the Rio das Velhas Basin and displays both good water quantity and quality within the Belo Horizonte metropolitan area. The Taquaraçu is a tributary of the Rio das Velhas, and it was proposed that the Taquaraçu waters dilute pollutant concentrations entering the Rio das Velhas, thereby improving downstream water quality. This study evaluated statistically the impact of the Rio Taquaraçu on water quality in the Rio das Velhas. For this analysis, we used data collected between 1997 and 2015 from sampling points established by the Minas Gerais Estate Institute of Water Management(IGAM) in the Rio Vermelho, in the Rio Taquaraçu, and in upstream and downstream sites (the Rio Taquaraçu input) of the Rio das Velhas. Box-plots were created for water quality variables and a Principal Component Analysis (PCA) was run for periods referred to as “dry” and “wet.” Despite receiving sewage releases from cities in its watershed, the Rio Taquaraçu maintains good water quality. Nevertheless, our results indicate that inflow from the Rio Taquaraçu is insufficient to mitigate the poor water quality of the Rio das Velhas.

AbstractIntroductionLocked-In Syndrome is admittedly the worst case of motor and speech impairment, it seriously damages the ability of oral and gestural communication of patients. In recent years, alternative and augmentative communication technology has provided resources to restore these patients' ability to communicate.MethodsIn order to relate and classify the main methods with that purpose, this work conducted a systematic review on several journal databases.ResultsWe found 203 related papers and 55 of them were selected to compose the study. After that, we classified them into three major groups and we identified the main difficulties when using each approach.ConclusionIn order to overcome these difficulties, we propose a new system concept to develop an adaptive, robust and low cost communication environment. The proposed system is composed of five modules: data entry, communication, aid to the caregiver and external interaction.

As diversas técnicas para o tratamento cirúrgico da Síndrome do Intestino Curto apresentam, ainda hoje, problemas de difícil resolução. De todas, as mais promissoras são o transplante de intestino delgado e o transplante de colo. Uma técnica intermediária que mostrou resultados controversos tanto clínicos como experimentais, é a interposição de segmentos de colo no trajeto do intestino delgado após extensas ressecções. Sua aplicação serve, todavia, como um meio de se estudar a adaptação do colo, inclusive visando os transplantes. Neste trabalho foi estudada a indução de tumores pela 1,2-dimetilhidrazina, sua localização e grau de atipia nos diferentes segmentos intestinais após ressecção de 80% do jejuno-íleo. Foram encontradas 24 lesões ao exame macroscópico após a décima sexta semana de pós-operatório. O número de lesões por animal variou de 0 a 9. Das 24 lesões encontradas, 20 estavam no colo (83,33%), sendo que 11 estavam localizadas no cólon proximal, 3 no cólon distal e 6 anorretais. No estudo histológico, a maioria das lesões era de grau III. Este trabalho mostrou que o método de indução de tumores pela 1,2-dimetilhidrazina é apropriado para o estudo de tumores intestinais em ratos.

The techniques for surgical treatment of Short Bowel Syndrome are feasible, yet they have not solved the problems related to them. Small bowel transplantation and, more recently, colon transplantation, have being studied these days. An intermediate solution, with controversial results, is colon interposition between small bowel segments after extensive intestinal resection. Yet controversial, it is suitable as a method for adaptational studies. We studied colon tumors induced by 1,2-dimethylhydrazine in rats, after 80% jejunum-ileum resection. Twenty four tumors were found macroscopically 16 weeks after operation. Tumors per animal ranged from 0 to 9. Twenty out of twenty four lesions were located in the colon (83,33%), 11 of them at the proximal colon, 3 at the distal colon and 6 at the anorectal region. Histologically, most of the lesions were of grade III. This method is feasible for studying intestinal tumors in rats.