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Publications

Publications by CTM

2023

Discrete Representation of Photovoltaic Modules

Authors
Massaranduba, AB; Coelho, B; Machado, E; Silva, E; Pinto, A;

Publication
IEEE Latin America Transactions

Abstract

2023

Parkinson’s disease effective biomarkers based on Hjorth features improved by machine learning

Authors
Coelho, BFO; Massaranduba, ABR; Souza, CAdS; Viana, GG; Brys, I; Ramos, RP;

Publication
Expert Systems with Applications

Abstract

2023

Artifact removal for emotion recognition using mutual information and Epanechnikov kernel

Authors
Grilo, M; Moraes, CP; Oliveira Coelho, BF; Massaranduba, ABR; Fantinato, D; Ramos, RP; Neves, A;

Publication
Biomedical Signal Processing and Control

Abstract

2023

Error Analysis on Industry Data: Using Weak Segment Detection for Local Model Agnostic Prediction Intervals

Authors
Mamede, R; Paiva, N; Gama, J;

Publication
Discovery Science - 26th International Conference, DS 2023, Porto, Portugal, October 9-11, 2023, Proceedings

Abstract
Machine Learning has been overtaken by a growing necessity to explain and understand decisions made by trained models as regulation and consumer awareness have increased. Alongside understanding the inner workings of a model comes the task of verifying how adequately we can model a problem with the learned functions. Traditional global assessment functions lack the granularity required to understand local differences in performance in different regions of the feature space, where the model can have problems adapting. Residual Analysis adds a layer of model understanding by interpreting prediction residuals in an exploratory manner. However, this task can be unfeasible for high-dimensionality datasets through hypotheses and visualizations alone. In this work, we use weak interpretable learners to identify regions of high prediction error in the feature space. We achieve this by examining the absolute residuals of predictions made by trained regressors. This methodology retains the interpretability of the identified regions. It allows practitioners to have tools to formulate hypotheses surrounding model failure on particular regions for future model tunning, data collection, or data augmentation on critical cohorts of data. We present a way of including information on different levels of model uncertainty in the feature space through the use of locally fitted Model Agnostic Prediction Intervals (MAPIE) in the identified regions, comparing this approach with other common forms of conformal predictions which do not take into account findings from weak segment identification, by assessing local and global coverage of the prediction intervals. To demonstrate the practical application of our approach, we present a real-world industry use case in the context of inbound retention call-centre operations for a Telecom Provider to determine optimal pairing between a customer and an available assistant through the prediction of contracted revenue. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

2022

Wi-Fi Rate Adaptation using a Simple Deep Reinforcement Learning Approach

Authors
Queiros, R; Almeida, EN; Fontes, H; Ruela, J; Campos, R;

Publication
2022 27TH IEEE SYMPOSIUM ON COMPUTERS AND COMMUNICATIONS (IEEE ISCC 2022)

Abstract
The increasing complexity of recent Wi-Fi amendments is making optimal Rate Adaptation (RA) a challenge. The use of classic algorithms or heuristic models to address RA is becoming unfeasible due to the large combination of configuration parameters along with the variability of the wireless channel. We propose a simple Deep Reinforcement Learning approach for the automatic RA in Wi-Fi networks, named Data-driven Algorithm for Rate Adaptation (DARA). DARA is standard-compliant. It dynamically adjusts the Wi-Fi Modulation and Coding Scheme (MCS) solely based on the observation of the Signal-to-Noise Ratio (SNR) of the received frames at the transmitter. Our simulation results show that DARA achieves higher throughput when compared with Minstrel High Throughput (HT)

2022

Wi-Fi Rate Adaptation using a Simple Deep Reinforcement Learning Approach

Authors
Queirós, R; Almeida, EN; Fontes, H; Ruela, J; Campos, R;

Publication
CoRR

Abstract

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