Pernambuco
Prioritizing Samples in Reinforcement Learning with Reducible Loss
Most reinforcement learning algorithms take advantage of an experience replay buffer to repeatedly train on samples the agent has observed in the past. Not all samples carry the same amount of significance and simply assigning equal importance to each of the samples is a naive strategy. In this paper, we propose a method to prioritize samples based on how much we can learn from a sample.
The Brazilian Director Who's Up for Multiple Oscars
Kleber Mendonรงa Filho wants his films to reclaim lost history. For Kleber Mendonรงa Filho, filmmaking is an act of both provocation and preservation. Mendonรงa was born in 1968, in the early years of a ruthless military dictatorship--a time when cinema, like much else, was harshly constrained. His mother, Joselice Jucรก, was a historian who studied Brazil's abolitionist movement, and she taught him that filling gaps in the cultural memory was a way to expose concealed truths. His relationship with film is inextricably linked with his home town, Recife--a port city where attractive beaches and high-rise developments coexist with sprawling favelas and rampant crime. In his youth, Mendonรงa was fascinated by the city's grand cinema palaces. He carried a Super 8 camera to the tops of marquees and shot dizzying images; he spent hours in projection booths, learning the mechanics of how films reached the screen. Over time, Mendonรงa watched those theatres fall into decline, an experience that he likened to being aboard a ship as it wrecked. But even as Recife lost its allure, he made the city a fixture of his films--a way of vindicating its place in history. His first narrative feature, "Neighboring Sounds," takes place on a street where he lived as a child, a setting that he spent years documenting. Later, he made "Pictures of Ghosts," a documentary about Recife told largely through its cinemas.
Support Vector Machine-Based Burnout Risk Prediction with an Interactive Interface for Organizational Use
Teodosio, Bruno W. G., Lira, Mรกrio J. O. T., Araรบjo, Pedro H. M., Farias, Lucas R. C.
Burnout is a psychological syndrome marked by emotional exhaustion, depersonalization, and reduced personal accomplishment, with a significant impact on individual well-being and organizational performance. This study proposes a machine learning approach to predict burnout risk using the HackerEarth Employee Burnout Challenge dataset. Three supervised algorithms were evaluated: nearest neighbors (KNN), random forest, and support vector machine (SVM), with model performance evaluated through 30-fold cross-validation using the determination coefficient (R2). Among the models tested, SVM achieved the highest predictive performance (R2 = 0.84) and was statistically superior to KNN and Random Forest based on paired $t$-tests. To ensure practical applicability, an interactive interface was developed using Streamlit, allowing non-technical users to input data and receive burnout risk predictions. The results highlight the potential of machine learning to support early detection of burnout and promote data-driven mental health strategies in organizational settings.
Discovering Software Parallelization Points Using Deep Neural Networks
Correia, Izavan dos S., Santos, Henrique C. T., Ferreira, Tiago A. E.
This study proposes a deep learning-based approach for discovering loops in programming code according to their potential for parallelization. Two genetic algorithm-based code generators were developed to produce two distinct types of code: (i) independent loops, which are parallelizable, and (ii) ambiguous loops, whose dependencies are unclear, making them impossible to define if the loop is parallelizable or not. The generated code snippets were tokenized and preprocessed to ensure a robust dataset. Two deep learning models - a Deep Neural Network (DNN) and a Convolutional Neural Network (CNN) - were implemented to perform the classification. Based on 30 independent runs, a robust statistical analysis was employed to verify the expected performance of both models, DNN and CNN. The CNN showed a slightly higher mean performance, but the two models had a similar variability. Experiments with varying dataset sizes highlighted the importance of data diversity for model performance. These results demonstrate the feasibility of using deep learning to automate the identification of parallelizable structures in code, offering a promising tool for software optimization and performance improvement.
Perceptual Influence: Improving the Perceptual Loss Design for Low-Dose CT Enhancement
Viana, Gabriel A., Pereira, Luis F. Alves, Ren, Tsang Ing, Cavalcanti, George D. C., Sijbers, Jan
Perceptual losses have emerged as powerful tools for training networks to enhance Low-Dose Computed Tomography (LDCT) images, offering an alternative to traditional pixel-wise losses such as Mean Squared Error, which often lead to over-smoothed reconstructions and loss of clinically relevant details in LDCT images. The perceptual losses operate in a latent feature space defined by a pretrained encoder and aim to preserve semantic content by comparing high-level features rather than raw pixel values. However, the design of perceptual losses involves critical yet underexplored decisions, including the feature representation level, the dataset used to pretrain the encoder, and the relative importance assigned to the perceptual component during optimization. In this work, we introduce the concept of perceptual influence (a metric that quantifies the relative contribution of the perceptual loss term to the total loss) and propose a principled framework to assess the impact of the loss design choices on the model training performance. Through systematic experimentation, we show that the widely used configurations in the literature to set up a perceptual loss underperform compared to better-designed alternatives. Our findings show that better perceptual loss designs lead to significant improvements in noise reduction and structural fidelity of reconstructed CT images, without requiring any changes to the network architecture. We also provide objective guidelines, supported by statistical analysis, to inform the effective use of perceptual losses in LDCT denoising. Our source code is available at https://github.com/vngabriel/perceptual-influence.