2025
Autores
Gaudio, A; Giordano, N; Elhilali, M; Schmidt, S; Renna, F;
Publicação
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
Abstract
The detection of Pulmonary Hypertension (PH) from the computer analysis of digitized heart sounds is a low-cost and non-invasive solution for early PH detection and screening. We present an extensive cross-domain evaluation methodology with varying animals (humans and porcine animals) and varying auscultation technologies (phonocardiography and seisomocardiography) evaluated across four methods. We introduce PH-ELM, a resource-efficient PH detection model based on the extreme learning machine that is smaller (300x fewer parameters), energy efficient (532x fewer watts of power), faster (36x faster to train, 44x faster at inference), and more accurate on out-of-distribution testing (improves median accuracy by 0.09 area under the ROC curve (auROC)) in comparison to a previously best performing deep network. We make four observations from our analysis: (a) digital auscultation is a promising technology for the detection of pulmonary hypertension; (b) seismocardiography (SCG) signals and phonocardiography (PCG) signals are interchangeable to train PH detectors; (c) porcine heart sounds in the training data can be used to evaluate PH from human heart sounds (the PH-ELM model preserves 88 to 95% of the best in-distribution baseline performance); (d) predictive performance of PH detection can be mostly preserved with as few as 10 heartbeats and capturing up to approximately 200 heartbeats per subject can improve performance.
2025
Autores
Sulun, S; Viana, P; Davies, MEP;
Publicação
CoRR
Abstract
2025
Autores
Matos, T; Rocha, JL; Dinis, H; Martins, MS; Goncalves, LM;
Publicação
OCEANS 2025 BREST
Abstract
Estuaries are dynamic ecosystems where freshwater and seawater interact, shaping complex hydrodynamic and environmental processes. Traditional single-node monitoring systems, while informative, lack the spatial resolution necessary to fully capture these dynamics. This study presents the development and deployment of a dual-node synchronized wireless sensor network for real-time environmental monitoring in the Cavado Estuary, Portugal. The network architecture integrates low-power embedded systems, a synchronized radiofrequency network, and a web-based data visualization platform. Two monitoring nodes, deployed 675 meters apart, operate in a synchronous cycle to measure hydrostatic pressure and water temperature, demonstrating the feasibility of synchronized environmental sensing. The collected data validated network synchronization, revealing a 30-minute delay in tidal propagation between nodes and highlighting temperature variations influenced by estuarine hydrodynamics. Additionally, long-term observations captured seasonal trends, tidal influences, and extreme weather events such as Storm Kirk. The study also evaluated the system's energy efficiency, confirming the solar panel's capacity to sustain continuous operation and estimating battery life expectancy under different network configurations. This work advances synchronized monitoring networks by providing a scalable, low-cost solution for studying marine environments. The proposed system enables more precise quantification of oceanic influences on estuarine conditions, particularly regarding tidal propagation and phase differences, supporting more effective ecosystem management and understanding.
2025
Autores
Ghorvei, M; Karhu, T; Hietakoste, S; Ferreira Santos, D; Hrubos Strom, H; Islind, AS; Biedebach, L; Nikkonen, S; Leppaenen, T; Rusanen, M;
Publicação
JOURNAL OF SLEEP RESEARCH
Abstract
Obstructive sleep apnea is a heterogeneous sleep disorder with varying phenotypes. Several studies have already performed cluster analyses to discover various obstructive sleep apnea phenotypic clusters. However, the selection of the clustering method might affect the outputs. Consequently, it is unclear whether similar obstructive sleep apnea clusters can be reproduced using different clustering methods. In this study, we applied four well-known clustering methods: Agglomerative Hierarchical Clustering; K-means; Fuzzy C-means; and Gaussian Mixture Model to a population of 865 suspected obstructive sleep apnea patients. By creating five clusters with each method, we examined the effect of clustering methods on forming obstructive sleep apnea clusters and the differences in their physiological characteristics. We utilized a visualization technique to indicate the cluster formations, Cohen's kappa statistics to find the similarity and agreement between clustering methods, and performance evaluation to compare the clustering performance. As a result, two out of five clusters were distinctly different with all four methods, while three other clusters exhibited overlapping features across all methods. In terms of agreement, Fuzzy C-means and K-means had the strongest (kappa = 0.87), and Agglomerative hierarchical clustering and Gaussian Mixture Model had the weakest agreement (kappa = 0.51) between each other. The K-means showed the best clustering performance, followed by the Fuzzy C-means in most evaluation criteria. Moreover, Fuzzy C-means showed the greatest potential in handling overlapping clusters compared with other methods. In conclusion, we revealed a direct impact of clustering method selection on the formation and physiological characteristics of obstructive sleep apnea clusters. In addition, we highlighted the capability of soft clustering methods, particularly Fuzzy C-means, in the application of obstructive sleep apnea phenotyping.
2025
Autores
Aline dos Santos Silva; Miguel Velhote Correia; Andreia Gonçalves da Costa; Hugo Plácido da Silva;
Publicação
2025 IEEE 8th Portuguese Meeting on Bioengineering (ENBENG)
Abstract
2025
Autores
Teixeira, FB; Ricardo, M; Coelho, A; Oliveira, HP; Viana, P; Paulino, N; Fontes, H; Marques, P; Campos, R; Pessoa, L;
Publicação
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING
Abstract
Telecommunications and computer vision solutions have evolved significantly in recent years, allowing a huge advance in the functionalities and applications offered. However, these two fields have been making their way as separate areas, not exploring the potential benefits of merging the innovations brought from each of them. In challenging environments, for example, combining radio sensing and computer vision can strongly contribute to solving problems such as those introduced by obstructions or limited lighting. Machine learning algorithms, able to fuse heterogeneous and multi-modal data, are also a key element for understanding and inferring additional knowledge from raw and low-level data, able to create a new abstracting level that can significantly enhance many applications. This paper introduces the CONVERGE vision-radio concept, a new paradigm that explores the benefits of integrating two fields of knowledge towards the vision of View-to-Communicate, Communicate-to-View. The main concepts behind this vision, including supporting use cases and the proposed architecture, are presented. CONVERGE introduces a set of tools integrating wireless communications and computer vision to create a novel experimental infrastructure that will provide open datasets to the scientific community of both experimental and simulated data, enabling new research addressing various 6 G verticals, including telecommunications, automotive, manufacturing, media, and health.
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