2025
Authors
Grozea-Banica, B; Miguéis, V; Patrício, L;
Publication
ENERGY RESEARCH & SOCIAL SCIENCE
Abstract
Engagement in the ongoing energy transition is particularly challenging for energy-poor citizens. As such, there is a pressing need for a better understanding of their experiences and for strategies that enable their engagement. In this study, we identify different groups of citizens based on their energy poverty issues and examine their engagement behaviors (seeking information, proactive managing, sharing feedback, helping others, and advocating). Using cluster analysis and multiple correspondence analysis, we analyzed a sample of 915 citizens from eight European cities participating in a Horizon2020 EU project (Alkmaar-NL, Bari-IT, Celje-SI, Evora-PT, Granada-ES, Hvidovre-DK, Ioannina-GR, & Uacute;jpest-HU). Several groups of citizens reported either multiple energy issues, a single issue (energy bills, insulation, cooling, heating), or no issues, and the statistical tests showed significant differences across these groups in terms of engagement in seeking information, helping, and advocating. Moreover, we identified that certain groups tend to have specific levels of engagement (high, medium, low) and that sharing feedback generally has a low level of engagement. Overall, this study provides empirical insights into how energy-poor citizens exercise agency through engagement behaviors and offers actionable insights for designing measures to mitigate energy poverty in complementarity with technical and economical solutions.
2025
Authors
Aubard, M; Madureira, A; Teixeira, L; Pinto, J;
Publication
IEEE JOURNAL OF OCEANIC ENGINEERING
Abstract
With the growing interest in underwater exploration and monitoring, autonomous underwater vehicles have become essential. The recent interest in onboard deep learning (DL) has advanced real-time environmental interaction capabilities relying on efficient and accurate vision-based DL models. However, the predominant use of sonar in underwater environments, characterized by limited training data and inherent noise, poses challenges to model robustness. This autonomy improvement raises safety concerns for deploying such models during underwater operations, potentially leading to hazardous situations. This article aims to provide the first comprehensive overview of sonar-based DL under the scope of robustness. It studies sonar-based DL perception task models, such as classification, object detection, segmentation, and simultaneous localization and mapping. Furthermore, this article systematizes sonar-based state-of-the-art data sets, simulators, and robustness methods, such as neural network verification, out-of-distribution, and adversarial attacks. This article highlights the lack of robustness in sonar-based DL research and suggests future research pathways, notably establishing a baseline sonar-based data set and bridging the simulation-to-reality gap.
2025
Authors
Vrancic, D; Bisták, P; Huba, M; Oliveira, PM;
Publication
MATHEMATICS
Abstract
The paper presents a new control concept based on the process moment instead of the process states or the process output signal. The control scheme is based on separate control of reference tracking and disturbance rejection. The tracking control is achieved by additionally feeding the input of the process model by the scaled output signal of the process model. The advantage of such feedback is that the final state of the process output can be analytically calculated and used for control instead of the actual process output value. The disturbance rejection, including model imperfections, is controlled by feeding back the filtered difference between the process output and the model output to the process input. The performance of tracking and disturbance rejection is simply controlled by two user-defined gains. Several examples have shown that the new control method provides very good and stable tracking and disturbance rejection performance.
2025
Authors
Martinez-Rodrigo, A; Saz-Lara, A; Pedrosa, J; Otero-Luis, I; Moreno-Herraiz, N; Lever-Megina, CG; Martínez-Ortega, IA; Pastor, JM; Cavero-Redondo, I;
Publication
INTERNATIONAL JOURNAL OF DATA SCIENCE AND ANALYTICS
Abstract
The aim of this study was to identify and validate distinct patterns of vascular aging, focusing on a novel high-risk vascular aging (HRVA) cluster. Key biomarkers such as aortic pulse wave velocity, glycated hemoglobin, pulse pressure, and advanced glycation end-products were used to enhance cardiovascular risk stratification and explore implications for targeted interventions. Data from multiple studies were integrated, and K-means clustering identified three vascular aging patterns: healthy vascular aging (HVA), early vascular aging (EVA), and high-risk vascular aging (HRVA). ROC analysis determined optimal thresholds for key biomarkers. ANOVA and Chi-square tests evaluated differences and associations across clusters, supported by contingency tables and residual analysis. The HRVA cluster exhibited significantly elevated biomarker levels compared to the HVA and EVA clusters. Statistically significant differences were observed across clusters (p <=\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le $$\end{document} 0.001), confirmed by ANOVA. Chi-square tests revealed strong associations between cluster membership and categorical variables, further validating the distinct profiles. The HRVA group demonstrated a particularly high risk of adverse cardiovascular events, emphasizing the clinical relevance. The identification of the HRVA cluster provides new insights into vascular aging, suggesting the need for intensive, personalized interventions. Future research should focus on validating these clusters longitudinally and exploring genetic, environmental, and lifestyle factors to improve cardiovascular outcomes.
2025
Authors
Oliveira, F; Mendes, A; Carreira, C;
Publication
ISSRE
Abstract
Software reliability is critical in ensuring that the digital systems we depend on function correctly. In software development, increasing software reliability often involves testing. However, for complex and critical systems, developers can use Design by Contract (DbC) methods to define precise specifications that software components must satisfy. Verification-Aware (VA) programming languages support DbC and formal verification at compile-time or run-time, offering stronger correctness guarantees than traditional testing. However, despite the strong guarantees provided by VA languages, their adoption remains limited. In this study, we investigate the barriers to adopting VA languages by analyzing developer discussions on public forums using topic modeling techniques. We complement this analysis with a developer survey to better understand the practical challenges associated with VA languages. Our findings reveal key obstacles to adoption, including steep learning curves and usability issues. Based on these insights, we identify actionable recommendations to improve the usability and accessibility of VA languages. Our findings suggest that simplifying tool interfaces, providing better educational materials, and improving integration with everyday development environments could improve the usability and adoption of these languages. Our work provides actionable insights for improving the usability of VA languages and making verification tools more accessible. © 2025 IEEE.
2025
Authors
Elhawash, AM; Araújo, RE; Lopes, JAP;
Publication
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
Abstract
Maintaining frequency stability is one of the biggest challenges facing future power systems, due to the increasing penetration levels of inverter-based renewable resources. This investigation experimentally validates the frequency provision capabilities of a real Polymer Electrolyte Membrane (PEM) hydrogen electrolyser (HE) using a power hardware-in-the-loop (PHIL) setup. The PHIL consists of a custom 3-level interleaved buck converter and a hardware platform for real-time control of the converter and conducting grid simulation, associated with the modelling of the future Iberian Peninsula (IP) and Continental Europe (CE) systems. The investigation had the aim of validating earlier simulation work and testing new responses from the electrolyser when providing different frequency services at different provision volumes. The experimental results corroborate earlier simulation results and capture extra electrolyser dynamics as the double-layer capacitance effect, which was absent in the simulations. Frequency Containment Reserve (FCR) and Fast Frequency Response (FFR) were provided successfully from the HE at different provision percentages, enhancing the nadir and the rate of change of frequency (RoCoF) in the power system when facing a large disturbance compared to conventional support only. The results verify that HE can surely contribute to frequency services, paving the way for future grid support studies beyond simulations.
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