Nilton Silva

• PhD
• Professor at University of Brasília

The Brazilian Supreme Court receives tens of thousands of cases each semester. Court employees spend thousands of hours to execute the initial analysis and classification of those cases—which takes effort away from posterior, more complex stages of the case management workflow. In this paper, we explore multimodal classification of documents from B...

Resumo A Segurança Alimentar é um tema importante para a saúde pública e o comércio internacional de alimentos. Resíduos de medicamentos veterinários e contaminantes ambientais em produtos de origem animal podem causar doenças e toxicidade aguda em organismos expostos a essas substâncias. Este estudo avaliou dados oficiais de monitoramento de resíd...

Food Safety is an important topic for public health and international trade in food. Residues of veterinary drugs and environmental contaminants in animal products can cause diseases and acute toxicity in organisms exposed to these substances. This study evaluated official monitoring data of veterinary drug residues from the Brazilian Ministry of A...

The Brazilian Supreme Court receives tens of thousands of cases each semester. Court employees spend thousands of hours to execute the initial analysis and classification of those cases -- which takes effort away from posterior, more complex stages of the case management workflow. In this paper, we explore multimodal classification of documents fro...

The separation of documents contained in a page stream is a critical activity in some segments. That is the case of the Brazilian judiciary system since it is overwhelmed with files resulting from batch scanning of lawsuits, finishing in PDFs containing several types of mixed documents. To make such a file usable, we must divide it into cohesive se...

Both natural evolution and human activities result in changes in natural resources and in the terrestrial environment. Observation of the temporal and spatial level of the Earth allows us to understand the interrelationship of the phenomena that cause these changes. The studies carried out in this sense vary according to the need of the researchers...

Skin lesions are conditions that appear on a patient due to many different reasons. One of these can be because of an abnormal growth in skin tissue, defined as cancer. This disease plagues more than 14.1 million patients and had been the cause of more than 8.2 million deaths, worldwide. Therefore, the construction of a classification model for 12...

The Brazilian court system is currently the most clogged up judiciary system in the world. Thousands of lawsuit cases reach the supreme court every day. These cases need to be analyzed in order to be associated to relevant tags and allocated to the right team. Most of the cases reach the court as raster scanned documents with widely variable levels...

A história ambiental é um campo historiográfico relativamente novo. No entanto, seu desenvolvimento no campo científico tem se pautado pela utilização de ferramentas e metodologias que nem sempre foram utilizadas pela historiografia tradicional, sobretudo por lidar, de forma interdisciplinar com o meio ambiente. Esse artigo objetiva relacionar os e...

Speckle noise (salt and pepper) is inherent to synthetic aperture radar (SAR), which causes a usual noise-like granular aspect and complicates the image classification. In SAR image analysis, the spatial information might be a particular benefit for denoising and mapping classes characterized by a statistical distribution of the pixel intensities f...

Remote sensing has been used in karst studies to identify limestone terrain, describe exokarst features, analyze karst depressions, and detect geological structures important to karst development. The aim of this work is to investigate the use of ASTER-, SRTM- and ALOS/PRISM-derived digital elevation models (DEMs) to detect and quantify natural kar...

Radiometric precision is difficult to maintain in orbital images due to several factors (atmospheric conditions, Earth-sun distance, detector calibration, illumination, and viewing angles). These unwanted effects must be removed for radiometric consistency among temporal images, leaving only land-leaving radiances, for optimum change detection. A v...

Self-organizing feature maps (SOFM) consist of a type of artificial neural network that allows the conversion from high-dimensional data into simple geometric relationships with low-dimensionality. This method can also be used for classification of remote sensing images because it allows the compression of highdimensional data while preserving the...

The present study aims to evaluate the multitemporal dynamics of sheep production in Brazil, considering the Federal Government's official data from 1976 to 2010. Principal Component Analysis (PCA) and Self-Organizing Maps (SOFM) were used. PCA reduced data redundancy and the colour composition of the first three principal components evidenced temp...

A geometria fractal torna-se uma alternativa a geometria euclidiana para a descrição de formas irregulares, rugosidade e textura de superfícies. A dimensão fractal tem sido utilizada, principalmente, no processamento de imagens médicas e observações microscópicas de morfologia de partículas. O presente trabalho objetiva implementar o algoritmo de d...

Consistent multi-temporal images are necessary for accurate landscape change detection and temporal signatures analysis. Orbital images have a difficultyto maintain a temporal information precision due to several interferences that generate missing data. In this paper is developed a program in C++ languagefor denoising MODIS temporal signatures con...

The need to monitor the Earth's surface over a range of spatial and temporal scales is fundamental in ecosystems planning and management. Change-Vector Analysis (CVA) is a bi-temporal method of change detection that considers the magnitude and direction of change vector. However, many multispectral applications do not make use of the direction comp...

O foco deste estudo foi saber as características do Município de João Dourado, Estado da Bahia, Região Nordeste do Brasil, onde foi detectados o primeiro caso confirmado de sarampo em 2006 e avaliar o impacto das ações de vigilância epidemiológicas adotadas para a contenção do mesmo. Foi avaliado o número de casos de sarampo por faixa etária, com a...

A savana é o principal tipo de vegetação no Brasil Central, cobrindo aproximadamente 23% do território nacional. Esta é formada por um mosaico de fisionomias com ciclos fenológicos típicos. Neste contexto, os dados do sensor MODIS fornecem medidas quase diárias que permitem monitorar a fenologia sazonal da vegetação. O presente trabalho objetivou a...

Savannas are the main vegetation type in Central Brazil, covering approximately 23% of the national territory. Locally known as Cerrado, Brazilian Savannas are formed by amosaic of different physiognomies such as grassland, shrubland and woodland that have atypical phenological cycle. ln this context, the MODIS data provide daily measurements well...

Savannas are the main vegetation type in Central Brazil, covering approximately 23% of the national territory. Locally known as Cerrado, Brazilian Savannas are formed by a mosaic of different physiognomies such as grassland, shrubland and woodland that have a typical phenological cycle. In this context, the MODIS data provide daily measurements wel...

A topologia e geometria das redes de drenagem têm contribuído substancialmente para os estudos em geomorfologia e hidrologia, incluindo modernos modelos de evolução da paisagem. Este trabalho tem como objetivo apresentar uma metodologia para extração automatizada de bacias e sub-bacias de drenagem e calcular seus atributos morfométricos agrupando-a...

Digital change detection is the computerized process of identifying changes in the state of an object or other earth-surface features between different dates. During the last years, a large number of change detection methods have evolved that differ widely in refinement, robustness, and complexity. This study aims to develop one program to detect a...

A consistent data acquisition interval among multi-temporal images is necessary to accurate landscape change detection and temporal-series signatures. Orbital images are difficult to maintain a temporal precision due to the different interferences that generate missing data. The correct handling of missing data is a difficult problem in data analys...

Orbital images are difficult to maintain a radiometric precision due to the sensor oscillation, atmosphere interferences, season variation of the solar illumination angle, among others. Thus, many radiometric correction techniques have been developed for time series considering mainly: (a) landscape elements whose reflectances are nearly constant o...

Spectral classifiers identify a particular element from comparing the degree of adjustment between the image spectrum and the reference spectrum that comes either from spectral libraries or from endmembers. However, these methods do not adopt the mixture concept integrally. The correlation of the mixture pixels should adopt not only the endmember s...

The spectral classifiers allow a good estimate for the mapping of the materials from the similarity between the reference curve and the image. Initially the spectral classifiers had been developed for hyperspectral images analysis. However, some works demonstrate good results for the application of these techniques in multispectral images. The pres...

This work presents the evaluation of the P-band data discrimination properties using Fuzzy-ART artificial neural network (AMN) unsupervised methodology for land cover mapping in the Amazon tropical forest.

Map Gauss filter is a linear adaptive filter commonly used to reduce speckle noise present in synthetic aperture radar images of remote sensing satellites. In this study was incorporating some modifications that allow us to maximize the signal-to-noise ratio at the same time almost total features of the image are preserved. To evalute the performan...

A parallel self-organizing map (parallel-SOM) is proposed to modify a self-organizing map for parallel computing environments. In this model, the conventional repeated learning procedure is modified to learn just once. The once learning manner is more similar to human learning and memorizing activities. During training, every connection between neu...

A study of Parallel Self-Organizing Map (Parallel-SOM) is proposed to modify Self-Organizing Map for parallel computing environments. In this model, the conventional repeated learning procedure is modified to learn just once. The once learning manner is more similar to human learning and memorizing activities. During training, every connection betw...

The development of parallel applications usually require the use of different techniques for each of the phases of development. The paper reports on the process of moving from the design of a parallel real time application into its implementation using the Parallel Program Generator. This tool is part of a visual environment for the development of...

The teaching environment described here is introduced as an effective way for learning how to deal with the problems related with parallel/distributed real-time systems. The educational process has three main domains: the cognitive; the affective; and the psychomotor. Normally, the student dominates the first, but lacks more interest for the subjec...

The objective of this study is to show the applicability of the genetic synthesis of the unsupervised artificial neural network ART2 (Adaptive Resonance Theory) in the classification of ASTER image for land use/land cover mapping. The area under study is located in northern Mato Grosso State, Brazil, and is characterized by a strong human occupatio...

Recebido 01 de junho de 2009; revisado 03 de agosto; aceito 13 de agosto. RESUMO – O presente artigo tem como objetivo utilizar um framework para desenvol-vimento de aplicações (QT) visando à elaboração de interfaces para visualização inte-grada de dados espaciais vetoriais. Para tanto, esta pesquisa baseia-se nos formalismos matemáticos referentes...

The present work is concerned with the potential application of artificial neural networks for the classification of polarimetric radar images operating in the P band. The study area is located near the Tapajós National Forest, in the northern State of Pará, Brazil, and comprises regions of dense rain forest partially disturbed by deforestation and...

This work presents the evaluatio of the P-ba d data discrimination properties using Fuzzy-ART artificial neural etwork (AMN)unsupervised methodology for la d cover mapping in the Amazonian tropical forest.