Brazil

Fake news propagation has been a problem noted in several areas of society, for example, in the fight against the pandemic caused by the new coronavirus (Sars-Cov-2). Combating misinformation, especially on social networks, is fundamental to control the spread of the virus and, consequently, the pandemic. Therefore, this work built supervised learning models focused on identifying fake news about the Sars-Cov-2. As a result, 18 models were built and rated, their reached 0.62%, 0.82%, and 0.47% f-score for the labels considered (news, opinion, and fake).

BRACIS 2021

Fake news detection about Covid-19 in the Portuguese language

social networks

fake news

machine learning

sentiment analysis

covid-19

**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. **STIL** is the bi-annual Language Technology event.
All events are supported by the Brazilian Computer Society – Special Interest Groups: **CE-IA**, **CE-IC** and **CE-PLN**.

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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. 
STIL is the bi-annual Language Technology event.
All events are supported by the Brazilian Computer Society – Special Interest Groups: CE-IA, CE-IC and CE-PLN

technical paper

Abstract. The Brazilian Exclusive Economic Zone, or the “Blue Amazon”, with its extensive maritime area, is the primary means of transport for the country’s foreign trade and is important due to its oil reserves, gas and other mineral resources, in addition to the significant influence on the Brazilian climate. We have manually built a question answering (QA) dataset based on crawled arti- cles and have applied an off-the-shelf QA system based on a fine-tuned BERTim- bau Model, achieving an F1-score of 47.0. More importantly, we explored how the proper visualization of attention weights can support helpful interpretations of the system’s answers, which is critical in real environments.


Interpretability of Attention in Question and Answering System about the Blue Amazon in Portuguese.

RBF-based neural networks models (RBFNN) are classic machine
learning methods that contain a layer of Radial Basis Functions (RBF) which
act as the feature extractor for the final layer, which performs the pattern recognition. The estimation of RBF radius during the model training is one of the most
crucial tasks for this method and directly affects its generalization power and
accuracy. This works presents a new heuristic for radius estimation and employs
computational experiments to assess its performance against other approaches
using 14 classification problems. The proposed method is shown competitive
performance, winning the other approaches in 9 out of 14 problems.

A New Heuristic for Radius Estimation in RBF Neural Networks

This talk will present the result of a time-series classification task on the stock market, compare the results with well-known methods. We propose the
Trend Classification Trading Algorithm (TCTA) which is based on time series
classification and trend forecasting to perform trade. TCTA first employs the
K-means to cluster 5-days closing price segments and label them according to
its trend. A deep learning classification model is then trained with these label
sequences to estimate the next trend. Trading points are given by the alternation
on trend estimates. Results considering 20 shares from Ibovespa show TCTA
present higher profit than buy-and-hold and trading schemes based on Moving
Average Convergence Divergence (MACD) or Bollinger bands.

A stock trading algorithm based on trend forecasting and time series classification

O objetivo do presente trabalho é investigar o desempenho de agentes jogadores baseados em aprendizado por reforço - mais especificamente, nos algoritmos Q-Learning e Deep Q-Networks (DQN) - por meio da plataforma Unity. Para tanto, os autores implementam nela agentes jogadores de Basic e GridWorld que são treinados segundo tais algoritmos. A fim de avaliar o desempenho desses agentes, foi efetuada uma análise comparativa entre eles e os melhores agentes jogadores desses jogos disponibilizados na plataforma Unity, os quais são baseados nas técnicas de aprendizagem Proximal Policy Optimization (PPO) e Soft Actor-Critic (SAC).

Técnicas de Aprendizado por Reforço Aplicadas em Jogos Eletrônicos na Plataforma Geral do Unity

Creating computer generated human animations without the use of motion capture technology is a tedious and time consuming activity. Although there are several publications regarding animation synthesis using data driven methods, not many are dedicated towards the task of inbetweening, which consists of generating transition movements between \textit{frames}.
In this work, we are interested on short-term transitions and different kinds of movement, such as martial arts and Indian dance using the least amount of input \textit{frames} as possible.

Short-term Inbetweening of 3D Human Motions

Due to the increasing use of artificial intelligence for decision making and the observation of biased decisions in many applications, researchers are investigating solutions that attempt to build fairer models that do not reproduce discrimination. Some of the explored strategies are based on adversarial learn- ing to achieve fairness in machine learning by encoding fairness constraints through an adversarial model. Moreover, it is usual for each proposal to assess its model with a specific metric, making comparing current approaches a com- plex task. In that sense, we defined a utility and fairness trade-off metric. We assessed 15 fair model implementations and a baseline model using this metric, providing a systemically comparative ruler for other approaches.

Assessing Fair Machine Learning Strategies Through a Fairness-Utility Trade-off Metric

The complexity of distributed algorithm’s distribution policies often impedes the use of established mathematical approaches for performance analysis, such as asymptotic analysis, recurrence techniques and probabilistic analysis. The aforementioned techniques have no proper means to assess the impact on the algorithm’s run time caused by the gradual increment of the number of processors. Therefore, this article proposes both a visual and formal approach for valuating the processor saturation point and speedup of distributed algorithms utilized in Artificial Intelligence, based on automatic simulations of Hierarchical Colored Petri Nets in the Colored Petri Nets Tools software. The aforementioned approach was demonstrated in a case study on the training of Multilayer Perceptrons based on error backpropagation

Speedup Evaluation of the Training Algorithm for a Multilayer Perceptron based on Colored Petri Nets Simulations

Social media have become trendy environments for communication. Because of that, analyze the sentiment that the user expresses in their social media posts is an important research field. However, detecting polarity in such contents is a challenge, partially because the amount of labeled data to train classifiers is scarce in many situations. This paper explores strategies for reusing a model learned from a source dataset to classify instances in a target dataset. The experiments are conducted with 22 tweets sentiment analysis datasets and approaches based on similarity metrics. The results point out that the size of the source training set plays an essential role in the classifiers’ performance when they were applied to the target data.

Exploring model transfer strategies for sentiment analysis in Twitter

The judicial system is composed of numerous court documents. These documents may contain relevant information that supports decision-making in future processes. However, collecting this information is not a trivial task. This article proposes the use of clustering techniques to group similar court lawsuits and facilitate the collection of information. In this way, different approaches were evaluated for identifying the most appropriate to perform this task. The approaches were applied to a database composed of 1515 facts of initial petitions. These approaches were evaluated using internal metrics and texts of the grouped court lawsuits. The results showed that the best approach to grouping court lawsuits is composed of the K-Means algorithm and the TF-IDF representation technique in combination with the PCA technique.

Assessment of text clustering approaches for legal documents

A propagação de desinformação trouxe e ainda traz diversos problemas para a sociedade, sendo 
considerada uma infodemia pela Organização Mundial da Saúde (OMS). A grande maioria dos trabalhos 
desenvolvidos para lidar com desinformação são focados para a língua inglesa. A fim de preencher 
essa lacuna, este trabalho investiga estratégias baseadas em aprendizado de máquina supervisionado 
para detectar desinformação em tweets escritos na língua portuguesa. Além disso, criou-se um 
corpus que foi manualmente anotado para esta tarefa, a fim de avaliar as abordagens 
desenvolvidas e compará-las com trabalhos relacionados. Os resultados alcançados são competitivos 
com trabalhos correlatos, indicando que a abordagem produz um interessante baseline para o 
corpus construído.


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Fake news detection about Covid-19 in the Portuguese language

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Interpretability of Attention in Question and Answering System about the Blue Amazon in Portuguese.

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