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Publications

Publications by LIAAD

2025

Automating Data Extraction from PDF Sleep Reports Using Data Mining Techniques

Authors
Teixeira, F; Costa, J; Amorim, P; Guimarães, N; Ferreira Santos, D;

Publication
Studies in health technology and informatics

Abstract
This work introduces a web application for extracting, processing, and visualizing data from sleep studies reports. Using Optical Character Recognition (OCR) and Natural Language Processing (NLP), the pipeline extracts over 75 key data points from four types of sleep reports. The web application offers an intuitive interface to view individual reports' details and aggregate data from multiple reports. The pipeline demonstrated 100% accuracy in extracting targeted information from a test set of 40 reports, even in cases with missing data or formatting inconsistencies. The developed tool streamlines the analysis of OSA reports, reducing the need for technical expertise and enabling healthcare providers and researchers to utilize sleep study data efficiently. Future work aims to expand the dataset for more complex analyses and imputation techniques.

2025

PolyNarrative: A Multilingual, Multilabel, Multi-domain Dataset for Narrative Extraction from News Articles

Authors
Nikolaidis, N; Stefanovitch, N; Silvano, P; Dimitrov, DI; Yangarber, R; Guimarães, N; Sartori, E; Androutsopoulos, I; Nakov, P; San Martino, GD; Piskorski, J;

Publication
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), ACL 2025, Vienna, Austria, July 27 - August 1, 2025

Abstract

2025

Human Experts vs. Large Language Models: Evaluating Annotation Scheme and Guidelines Development for Clinical Narratives

Authors
Fernandes, AL; Silvano, P; Guimarães, N; Silva, RR; Munna, TA; Cunha, LF; Leal, A; Campos, R; Jorge, A;

Publication
Proceedings of Text2Story - Eighth Workshop on Narrative Extraction From Texts held in conjunction with the 47th European Conference on Information Retrieval (ECIR 2025), Lucca, Italy, April 10, 2025.

Abstract
Electronic Health Records (EHRs) contain vast amounts of unstructured narrative text, posing challenges for organization, curation, and automated information extraction in clinical and research settings. Developing effective annotation schemes is crucial for training extraction models, yet it remains complex for both human experts and Large Language Models (LLMs). This study compares human- and LLM-generated annotation schemes and guidelines through an experimental framework. In the first phase, both a human expert and an LLM created annotation schemes based on predefined criteria. In the second phase, experienced annotators applied these schemes following the guidelines. In both cases, the results were qualitatively evaluated using Likert scales. The findings indicate that the human-generated scheme is more comprehensive, coherent, and clear compared to those produced by the LLM. These results align with previous research suggesting that while LLMs show promising performance with respect to text annotation, the same does not apply to the development of annotation schemes, and human validation remains essential to ensure accuracy and reliability. © 2025 Copyright for this paper by its authors.

2025

Using LLMs to Generate Patient Journeys in Portuguese: an Experiment

Authors
Munna, TA; Fernandes, AL; Silvano, P; Guimarães, N; Jorge, A;

Publication
Proceedings of Text2Story - Eighth Workshop on Narrative Extraction From Texts held in conjunction with the 47th European Conference on Information Retrieval (ECIR 2025), Lucca, Italy, April 10, 2025.

Abstract
The relationship of a patient with a hospital from admission to discharge is often kept in a series of textual documents that describe the patient’s journey. These documents are important to analyze the different steps of the clinical process and to make aggregated studies of the paths of patients in the hospital. In this paper, we explore the potential of Large Language Models (LLMs) to generate realistic and comprehensive patient journeys in European Portuguese, addressing the scarcity of medical data in this specific context. We employed Google’s Gemini 1.5 Flash model and utilized a dataset of 285 European Portuguese published case reports from the SPMI website, published by the Portuguese Society of Internal Medicine, as references for generating synthetic medical reports. Our methodology involves a sequential approach to generating a synthetic patient journey. Initially, we generate an admission report, followed by a discharge report. Subsequently, we generate a comprehensive patient journey that integrates the admission, multiple daily progress reports, and the discharge into a cohesive narrative. This end-to-end process ensures a realistic and detailed representation of the patient’s clinical pathway as a patient’s journey. The generated reports were rigorously evaluated by medical and linguistic professionals, as well as automatic metrics to measure the inclusion of key medical entities, similarity to the case report, and correct Portuguese variant. Both qualitative and quantitative evaluations confirmed that the generated synthetic reports are predominantly written in European Portuguese without the loss of important medical information from the case reports. This work contributes to developing high-quality synthetic medical data for training LLMs and advancing AI-driven healthcare applications in under-resourced language settings. © 2025 Copyright for this paper by its authors.

2025

Histopathological Imaging Dataset for Oral Cancer Analysis: A Study with a Data Leakage Warning

Authors
Nogueira, DM; Gomes, EF;

Publication
Proceedings of the 18th International Joint Conference on Biomedical Engineering Systems and Technologies, BIOSTEC 2025 - Volume 1, Porto, Portugal, February 20-22, 2025.

Abstract

2025

Leveraging Synthetic Data to Develop a Machine Learning Model for Voiding Flow Rate Prediction From Audio Signals

Authors
Alvarez, ML; Bahillo, A; Arjona, L; Nogueira, DM; Gomes, EF; Jorge, AM;

Publication
IEEE ACCESS

Abstract
Sound-based uroflowmetry (SU) is a non-invasive technique emerging as an alternative to traditional uroflowmetry (UF) to calculate the voiding flow rate based on the sound generated by the urine impacting the water in a toilet, enabling remote monitoring and reducing the patient burden and clinical costs. This study trains four different machine learning (ML) models (random forest, gradient boosting, support vector machine and convolutional neural network) using both regression and classification approaches to predict and categorize the voiding flow rate from sound events. The models were trained with a dataset that contains sounds from synthetic void events generated with a high precision peristaltic pump and a traditional toilet. Sound was simultaneously recorded with three devices: Ultramic384k, Mi A1 smartphone and Oppo Smartwatch. To extract the audio features, our analysis showed that segmenting the audio signals into 1000 ms segments with frequencies up to 16 kHz provided the best results. Results show that random forest achieved the best performance in both regression and classification tasks, with a mean absolute error (MAE) of 0.9, 0.7 and 0.9 ml/s and quadratic weighted kappa (QWK) of 0.99, 1.0 and 1.0 for the three devices. To evaluate the models in a real environment and assess the effectiveness of training with synthetic data, the best-performing models were retrained and validated using a real voiding sounds dataset. The results reported an MAE below 2.5 ml/s and a QWK above 0.86 for regression and classification tasks, respectively.

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