7 results on '"Machine Learning Algorithms"'
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2. Preprocessing procedures and supervised classification applied to a database of systematic soil survey
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Alan Pessoa Valadares, Ricardo Marques Coelho, and Stanley Robson de Medeiros Oliveira
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machine learning algorithms ,random forest ,tacit soil-landscape relationships ,digital soil mapping ,Agriculture (General) ,S1-972 - Abstract
ABSTRACT: Data Mining techniques play an important role in the prediction of soil spatial distribution in systematic soil surveying, though existing methodologies still lack standardization and a full understanding of their capabilities. The aim of this work was to evaluate the performance of preprocessing procedures and supervised classification approaches for predicting map units from 1:100,000-scale conventional semi-detailed soil surveys. Sheets of the Brazilian National Cartographic System on the 1:50,000 scale, “Dois Córregos” (“Brotas” 1:100,000-scale sheet), “São Pedro” and “Laras” (“Piracicaba” 1:100,000-scale sheet) were used for developing models. Soil map information and predictive environmental covariates for the dataset were obtained from the semi-detailed soil survey of the state of São Paulo, from the Brazilian Institute of Geography and Statistics (IBGE) 1:50,000-scale topographic sheets and from the 1:750,000-scale geological map of the state of São Paulo. The target variable was a soil map unit of four types: local “soil unit” name and soil class at three hierarchical levels of the Brazilian System of Soil Classification (SiBCS). Different data preprocessing treatments and four algorithms all having different approaches were also tested. Results showed that composite soil map units were not adequate for the machine learning process. Class balance did not contribute to improving the performance of classifiers. Accuracy values of 78 % and a Kappa index of 0.67 were obtained after preprocessing procedures with Random Forest, the algorithm that performed best. Information from conventional map units of semi-detailed (4th order) 1:100,000 soil survey generated models with values for accuracy, precision, sensitivity, specificity and Kappa indexes that support their use in programs for systematic soil surveying.
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- 2019
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3. Modelagem Geológica Implícita em Mina de Mármore no Complexo Metamórfico Passo Feio, Rio Grande do Sul, Brasil.
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Pasetto, Giovanni Argenta, Gonçalves, Ítalo Gomes, Guadagnin, Felipe, and dos Santos, Evandro Gomes
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GEOLOGICAL modeling ,AERIAL photographs ,SCALAR field theory ,DRONE aircraft ,MACHINE learning ,POINT cloud - Abstract
Copyright of Anuario do Instituto de Geociencias is the property of Universidade Federal do Rio de Janeiro, Instituto de Geociencias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
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4. PROPOSTA DE ÍNDICE PARA AVALIAÇÃO DE SITUAÇÃO DE VULNERABILIDADE SOCIAL À COVID-19.
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Ramalho Barros, Juliana, Barbara Gioia, Thamy, and Silva Vasques, Hérika
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COVID-19 , *MACHINE learning , *RANDOM forest algorithms , *SOCIAL history - Abstract
The health-disease process encompasses factors beyond genetic and biological susceptibility, but also includes variables linked to social and economic conditions that can lead to health vulnerability. The expanding situation of COVID-19 in Brazil has demonstrated how social inequalities affect this health-disease process; thus, evaluating such disparities can help the country confront the disease. The objective of this article was to establish an index to assess the situation of social vulnerability to COVID-19. From the 12 selected variables, the modeling identified those the predicted the occurrence of COVID-19 in the State of Goiás and the Federal District. For this, two machine learning algorithms were tested: Random Forest and XGBoost. The results indicated the most predictive variables were income status, the total hospitalizations for ailments classified as very vulnerable, and the percentage of the population working informally. Therefore, approximately 23% of the municipalities were classified with high to very high vulnerability. [ABSTRACT FROM AUTHOR]
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- 2020
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- View/download PDF
5. Estimation of corn crop yield based on multispectral images
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Carlos Alberto Matias de Abreu Junior, Martins, George Deroco, Marques, Douglas José, and Galo, Maria de Lourdes Bueno Trindade
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Yield ,Corn crops ,Multispectral images ,Spectral yield models ,Agronomia ,Machine learning algorithms ,Algoritmos de aprendizado de máquina ,Produtividade ,Imagens multiespectrais ,Agronomy ,CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOFISICA::SENSORIAMENTO REMOTO [CNPQ] ,Modelos espectrais de produtividade ,Produtividade agrícola ,Cultura do milho ,Dados geoespaciais - Abstract
FAU - Fundação de Apoio Universitário A estimativa de produtividade é um parâmetro agronômico importante para auxiliar o mercado nacional e internacional no que tange a demanda, capacidade de transporte e armazenamento de produtos agrícolas. Nesse sentido, para que a produtividade continue a ser monitorada, tornase necessário a criação de métodos que aprimorem o mapeamento dessa variável em campo. Nesse contexto, esta pesquisa apresenta como objetivo a definição do estádio fenológico ideal e geração de modelos para estimativa de produtividade em escala local, ou seja, utilizando dados de áreas de estudo distintas para treinamento e validação do modelo. Para isso, foram utilizadas imagens multiespectrais, advindas de diferentes sensores orbitais, juntamente com índices de vegetação derivados das bandas de cada satélite, e modelos gerados por meio de algoritmos de aprendizado de máquina, sendo eles, Máquinas de Vetores de Suporte (Support Vector Machine - SVM), Redes Neurais (Neural Net - NN), Florestas Aleatórias (Random Forest - RF) e Árvores Aleatórias (Random Trees - RT). No Capítulo 1, para a definição do estádio fenológico ideal, foram utilizadas imagens do satélite Planet. Já no Capítulo 2, para a geração de modelos de estimativa de produtividade, foi utilizada uma imagem do satélite Sentinel 2. Foram utilizadas como métricas avaliativas a raiz do erro médio quadrático em percentagem (Root Mean Square Error percentagem - RMSE%) e o Erro Absoluto Médio em porcentagem (Mean Absolute Percentagem Error - MAPE) para avaliar a acurácia e tendência das estimativas de produtividade. Pela análise da definição de um estádio fenológico ideal, concluiu-se que o modelo espectral baseado em imagem da fase fenológica reprodutiva R2 foi o que obteve o melhor RMSE% de 9,17% e o segundo melhor MAPE de 7,07%. Pela análise da geração de modelos de estimativa em escala local foi possível estimar a produtividade com um RMSE% e MAPE de 20,97% e 19,19%, respectivamente. Estimated yield is an important agronomic parameter for the domestic and international market in the demand, transport capacity and storage of agricultural products. In this respect, continuous yield monitoring requires the creation of methods to enhance mapping of this variable in the field. As such, this study aimed to determine the ideal phenological stage to estimate yield and generate models for this purpose on a local scale, that is, using data from different study areas to train and validate the model. To that end, we used multispectral images from different orbital sensors combined with vegetation indices from the reflectance bands of each satellite and models generated by the following machine learning algorithms: support vector machine (SVM), neural network (NN), random forest (RF) and random trees (RT). In Chapter 1, Planet satellite images were used to determine the ideal phenological stage and in Chapter 2, yield estimate models were generated via a Sentinel 2 satellite image. The root mean square error percentage (RMSE%) and mean absolute percentage error (MAPE) were used as evaluation metrics to assess the accuracy and trend of the yield estimates. Based on analysis to determine the ideal phenological stage, it was concluded that the spectral model based on the image of phenological stage R2 obtained the best RMSE% (9.17%) and second best MAPE (7.07%). The local-scale estimation models generated made it possible to estimate yield with an RMSE% and MAPE of 20.97 and 19.19%, respectively. Dissertação (Mestrado)
- Published
- 2022
6. Fourier transform infrared spectroscopy in the search for diagnostic markers in patients with acute myeloid leukemia
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FERREIRA, Marcos Guimarães, PEREIRA, Silma Regina Ferreira, SILVA, Robinson Sabino da, CASTELLANO, Lúcio Roberto Cançado, SANTOS, Clenilton Costa dos, and ALENCAR, Luciana Magalhães Rebelo
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Ciências da Saúde ,Leukemia ,Algoritmos de aprendizado de máquinas ,Screening ,Leucemia ,Espectroscopia ATR-FTIR ,Triagem ,Modos vibracionais ,Machine learning algorithms ,Vibrational modes ,ATRFTIR spectroscopy - Abstract
Submitted by Sheila MONTEIRO (sheila.monteiro@ufma.br) on 2021-11-13T21:40:38Z No. of bitstreams: 1 MARCOS-FERREIRA.pdf: 372455 bytes, checksum: 3b2fc1435bf1e79c05a9ee6a6684f0ce (MD5) Made available in DSpace on 2021-11-13T21:40:38Z (GMT). No. of bitstreams: 1 MARCOS-FERREIRA.pdf: 372455 bytes, checksum: 3b2fc1435bf1e79c05a9ee6a6684f0ce (MD5) Previous issue date: 2021-06-29 Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão - FAPEMA Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Acute myeloid leukemia (AML) is part of a group of hematologic neoplasms that are characterized by maturation blockade and exacerbated clonal proliferation of myeloid progenitors in the bone marrow or peripheral blood. Currently, the main diagnostic methods for this neoplasm depend on the presence of at least 20% of malignant cells in the bone marrow or peripheral blood, which generally coincides with the advanced stage of the disease. In addition, these methodologies require expensive equipment and supplies, as well as specialized labor, which makes the diagnosis of AML restricted only to large diagnostic or research centers. Therefore, in this work, we implement the use of Fourier Transform Infrared Spectroscopy and attenuated total reflection (ATR-FTIR) univariate and coupled with artificial intelligence algorithms, as a fast, inexpensive tool with high sensitivity and specificity for patient discrimination with clinical and laboratory diagnosis of acute myeloid leukemia. For this, we performed a quantitative spectral analysis of plasma (1μl) of 35 patients and 35 control subjects, with a resolution of 4 cm- 1 and 32 spectral scans in triplicate, using the air spectrum as the background of the analysis. As a result, ten vibrational modes were identified (3095 cm-1, 1648 cm-1, 1635 cm-1, 1540 cm-1, 1284 cm-1, 1170 cm-1, 1120 cm-1, 1078 cm-1, 1031 cm-1 and 850 cm-1) with sensitivity and specificity ≥80% (p
- Published
- 2021
7. Inteligência artificial na qualidade de dados - Referencial de tecnologias de IA para a melhoria da qualidade dos dados
- Author
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Ferreira, João Miguel Cardona and Santos, Vitor Manuel Pereira Duarte dos
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Artificial Intelligence ,Machine learning ,Data quality problems ,Machine learning algorithms ,Neural networks - Abstract
Dissertation presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Marketing Intelligence This study aims to contribute to a better understanding of the problematic of data quality problems. In these days, information took an important role in every organization, a data is a valuable asset, and we discuss the types of errors in this matter and look to the capabilities of new Artificial Intelligence tools to deal with those kinds of problems. Several common problems of data quality will be identified, analysed and paired with relevant Artificial Intelligence tools resulting in a conceptual framework that information managers and data officers can use to improve that problems that we identified as critical in this current scenario. Although, it will be not possible to present an exhaustive list of all existing solutions, due to the quick emerging of new techniques and ideas about this problems
- Published
- 2020
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