Brazil

Identifying subjective sentences and calculating the polarity of these sentences are two important tasks of sentiment analysis. Although they are not new problems, the most of solutions are focused on the English language. In this paper, we have proposed and evaluated an approach based on machine learning to handle both tasks in Portuguese. We investigated the use of two classifiers and also proposed a set of linguistic features extracted from the text. We experiment and evaluate the methods against a representative set of baselines and a diverse set of datasets. Our approach achieved the best results for both tasks and for all test datasets.

BRACIS 2020

Investigating Sentences Features for Subjectivity and Polarity Classification in Brazilian Portuguese

text features

sentiment analysis

natural language processing

The 9th Brazilian Conference on Intelligent Systems (BRACIS), the 16h Encontro Nacional de Inteligência Artificial e Computacional (ENIAC), and the 12th Concurso de Teses e Dissertações em Inteligência Artificial e Computacional (CTDIAC) was held from 20 to 23 October, 2020.

BRACIS originated from the combination of the two most important scientific events in Brazil in Artificial Intelligence (AI) and Computational Intelligence (CI): the Brazilian Symposium on Artificial Intelligence - SBIA (22 editions), and the Brazilian Symposium on Neural Networks - SBRN (13 editions). ENIAC is a national forum for researchers, practitioners, educators and students to present and discuss innovations, trends, experiences, developments and work in progress in the fields of Artificial and Computational Intelligence. CTDIAC is a satellite event whose goals are to disseminate and award the best dissertations and theses (MSc and PhDs concluded in Brazilian universities from June 2018 to May 2020) in Artificial and Computational Intelligence areas.

In this year, the Symposium on Knowledge Discovery, Mining and Learning (KDMiLe) will be held in conjunction with BRACIS 2020. This sysposium aims at integrating researchers, practitioners, developers, students and users to present their research results, to discuss ideas, and to exchange techniques, tools, and practical experiences – related to the Data Mining and Machine Learning areas.

technical paper

Displasia Cortical Focal (DCF) é um tipo de lesão cerebral que é a principal causa de Epilepsia Refratária em crianças, e o terceira maior causa em adultos, estando presente em mais de 50% dos casos infantis e 20% nos casos adultos. Pacientes com essa doença sofrem de crises epiléticas onde os remédios não são capazes de ajudar. O tratamento clínico mais indicado nesse caso é a cirurgia. Mas para ser realizada é necessário se ter uma identificação precisa da lesão. Esse processo é bastante complexo pois a região da lesão não é bem definida para visualização em Imagens de Ressonância Magnética (IRM). Porém com os avanços computacionais sugiram várias técnicas para o auxílio na classificação de imagens médicas. Neste trabalho é estudado o uso de Redes Neurais Convolucionais (CNN) para classificação de imagens com a presença da DCF. Foram utilizadas imagens no plano axial de 7 pacientes previamente diagnosticados com DCF. De cada paciente foram obtidos vários cortes e posteriormente cada corte foi divido em janelas de classificação. Estas janelas por sua vez foram utilizadas para realizar o treinamento e análise dos resultados obtidos da CNN. Os resultados obtidos nesse trabalho se mostraram bastante satisfatórios para classificação de janelas com DCF, porém a rede apresentou algumas dificuldades para classificar as janelas sem DCF. Com isso seu uso para demarcação em uma imagem completa ainda não se mostrou adequado. As limitações e novas abordagens são discutidas.

Use of Convolutional Neural Networks to Identify Focal Cortical Dysplasia in Patients with Refractory Epilepsy

Sports analytics, also known as scout, has gained significant atten-tion thanks to the positive results of its application in a wide variety of sports.Due to the popularity of football, several studies seek to apply Machine Lear-ning on scout data in this sport due to the popularity of soccer. This type ofdata comprises events countings, such as passes and finishes, and can assist thetechnical staffs’ decision-making process. However, these efforts are focused onEuropean football. In this work, we investigate the knowledge discovery usingMachine Learning algorithms in data from scout obtained in Brazilian soccer.With that, we show the current potential and limitations of this approach.

Knowledge Discovery in Brazilian Soccer Championship Scout Data

To guarantee a high indoor air quality is an increasingly important task. Sensors measure pollutants in the air and allow for monitoring and controlling air quality. However, all sensors are susceptible to failures, either permanent or transitory, that can yield incorrect readings. Automatically detecting such faulty readings is therefore crucial to guarantee sensors' reliability. In this paper we evaluate three Machine Learning algorithms applied to the task of classifying a single reading from a sensor as faulty or not, comparing them to standard statistical approaches. We show that all tested machine learning methods -- Multi-layer Perceptron, K-Nearest Neighbor and Random Forest -- outperform their statistical counterparts, both by allowing better separation boundaries and by allowing for the use of contextual information. We further show that this result does not depend on the amount of data, but ML methods are able to continue to improve as more data is made available.

Sensor Validation for Indoor Air Quality using Machine Learning

We use data from the 2017 Origin-Destination survey to build a representative contact network for the city of São Paulo, where individuals are connected by different social relations (school, work, neighborhood, household). The network is used to devise a discrete time and state compartmental model for the spread of the COVID-19. We employed the model to compare different mitigation strategies. The results show that even simple Monte Carlo planners greatly improve the performance over reactive strategies in terms of balancing the economical and the health impacts of non-pharmaceutical interventions.

A Contact Network-Based Approach for Online Planning of Containment Measures for COVID-19

A similarity search method based on the NK interaction graph is proposed. The NK interaction graph was originally employed for clustering and is built based on distance and spatial density of the objects in a dataset. Two variations of the method are investigated. In the two variations, k objects are returned by visiting vertices of the NK interaction graph from the initial vertex related to the example of the dataset that is closer to the object to be consulted. In NK A, the k objects related to vertices with edges incident to the initial vertex are returned. In NK B, k vertices are visited starting from the initial vertex. The next visited vertex is that one with edge incident to the current vertex and that is closest to the new object to be consulted. The k objects related to the visited vertices are returned. The proposed algorithms are compared with each other and with the search for similarity based only on distance. The experimental results indicate that the proposed methods present good performance when there are clusters with arbitrary shapes in the dataset.

Similarity Search using the NK Interaction Graph

Focal cortical dysplasia (FCD) is a local malformation of the cortex, the main cause of refractory epilepsy in childhood and one of the most common causes in adults. The surgery decision and planning depend on the FCD localization. Although recent studies have successfully detected FCD through artificial intelligence, no study investigates the relevance and prevalence of cortical features on FCD identification and the performance of different machine learning techniques. In this study, the proposed method constructed a voxel-based set of features, e.g., texture measure, border definition, cortical thickness.

Brain Tissue Classification to Detect Focal Cortical Dysplasia in Magnetic Resonance Imaging

A prática jurídica Brasileira tem convergido para o processamento de litígios por meio eletrônico, com a consequente diminuição progressiva das ações processadas fisicamente. A Constituição Federal, no artigo 5º, inciso V assegura a indenização pelo dano cível decorrente da violação de Direitos, como o Direito à vida, à liberdade, à igualdade, à segurança e à propriedade. Portanto, este estudo apresenta a ontologia a qual permite (utilizando os padrões da Web Semântica como a Lógica de Descrições) verificar se o caso em análise corresponde a um Dano Cível Indenizável. Os resultados alcançados até então apontam para a possibilidade da aplicação da Ontologia na prática jurídica/forense.

SIMULANDO INDENIZAÇÃO EM AÇÕES CIVIS POR MEIO DE ONTOLOGIAS BASEADAS NA LÓGICA DESCRITIVA

This work proposes a neural network architecture that learns policies for multiple agent classes in a heterogeneous multi-agent reinforcement setting. The proposed network uses directed labeled graph representations for states, encodes feature vectors of different sizes for different entity classes, uses relational graph convolution layers to model different communication channels between entity types and learns distinct policies for different agent classes, sharing parameters wherever possible. Results have shown that specializing the communication channels between entity classes is a promising step to achieve higher performance in environments composed of heterogeneous entities.

Towards Heterogeneous Multi-Agent Reinforcement Learning with Graph Neural Networks

Popular mobile applications receive millions of user reviews.
These reviews contain relevant information, such as problem reports and improvement suggestions. The reviews information is a valuable knowledge source for software requirements engineering since the analysis of the reviews feedback helps to make strategic decisions in order to improve the app quality. However, due to the large volume of texts, the manual extraction of the relevant information is an impracticable task. In this paper, we investigate and compare textual representation models for app reviews classification. We discuss different aspects and approaches for the reviews representation, analyzing from the classic Bag-of-Words models to the most recent state-of-the-art Pre-trained Neural Language models. Our findings show that the classic Bag-of-Words model, combined with a careful analysis of text pre-processing techniques, is still a competitive model. However, pre-trained neural language models showed to be more advantageous since it obtains good classification performance, provides significant dimensionality reduction, and deals more adequately with semantic proximity between the reviews' texts, especially the multilingual neural language models.

From Bag-of-Words to Pre-trained Neural Language Models: Improving Automatic Classification of App Reviews for Requirements Engineering

Stock market forecasting has been a quite popular challenge in machine learning research. Recently, studies have been using deep learning techniques, such as Convolutional Neural Networks (CNN), to perform regressions in prices or classification in the trading signal as an operation indication. 
However, these works have not yet achieved a satisfactory financial result. In this paper, we propose a financially profitable stock market method that uses a new approach called Multichannel CNN Trading Classifier (MCNN-TC).
The model was evaluated using data from the Brazilian stock market. The results indicate a promising financial trading performance compared to the Buy and Hold strategy and good classification metrics.

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