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Publications

2025

Enhancing spectral imaging with multi-condition image fusion

Authors
Teixeira, J; Lopes, T; Capela, D; Monteiro, CS; Guimaraes, D; Lima, A; Jorge, PAS; Silva, NA;

Publication
SCIENTIFIC REPORTS

Abstract
Spectral Imaging techniques such as Laser-induced Breakdown Spectroscopy (LIBS) and Raman Spectroscopy (RS) enable the localized acquisition of spectral data, providing insights into the presence, quantity, and spatial distribution of chemical elements or molecules within a sample. This significantly expands the accessible information compared to conventional imaging approaches such as machine vision. However, despite its potential, spectral imaging also faces specific challenges depending on the limitations of the spectroscopy technique used, such as signal saturation, matrix interferences, fluorescence, or background emission. To address these challenges, this work explores the potential of using techniques from conventional RGB imaging to enhance the dynamic range of spectral imaging. Drawing inspiration from multi-exposure fusion techniques, we propose an algorithm that calculates a global weight map using exposure and contrast metrics. This map is then used to merge datasets acquired with the same technique under distinct acquisition conditions. With case studies focused on LIBS and Raman Imaging, we demonstrate the potential of our approach to enhance the quality of spectral data, mitigating the impact of the aforementioned limitations. Results show a consistent improvement in overall contrast and peak signal-to-noise ratios of the merged images compared to single-condition images. Additionally, from the application perspective, we also discuss the impact of our approach on sample classification problems. The results indicate that LIBS-based classification of Li-bearing minerals (with Raman serving as the ground truth), is significantly improved when using merged images, reinforcing the advantages of the proposed solution for practical applications.

2025

Meta-learning and Data Augmentation for Stress Testing Forecasting Models

Authors
Inácio, R; Cerqueira, V; Barandas, M; Soares, C;

Publication
ADVANCES IN INTELLIGENT DATA ANALYSIS XXIII, IDA 2025

Abstract
The effectiveness of time series forecasting models can be hampered by conditions in the input space that lead them to underperform. When those are met, negative behaviours, such as higher-than-usual errors or increased uncertainty are shown. Traditionally, stress testing is applied to assess how models respond to adverse, but plausible scenarios, providing insights on how to improve their robustness and reliability. This paper builds upon this technique by contributing with a novel framework called MAST (Meta-learning and data Augmentation for Stress Testing). In particular, MAST is a meta-learning approach that predicts the probability that a given model will perform poorly on a given time series based on a set of statistical features. This way, instead of designing new stress scenarios, this method uses the information provided by instances that led to decreases in forecasting performance. An additional contribution is made, a novel time series data augmentation technique based on oversampling, that improves the information about stress factors in the input space, which elevates the classification capabilities of the method. We conducted experiments using 6 benchmark datasets containing a total of 97.829 time series. The results suggest that MAST is able to identify conditions that lead to large errors effectively.

2025

The Role of Mathematics in a PBL Approach in an Informatics Engineering Degree (LEI-ISEP)

Authors
Moura,, A; Bras,, H; Barata,, A; , E; , J; , A; Faria,, L;

Publication
Developing Teaching Competencies for Pedagogical and Curricular Innovation

Abstract
The Informatics Engineering degree at ISEP, aligned with international standards, was the first undergraduate degree in Portugal to be certified with EUR-ACE®. The programme emphasizes project-based learning, in which students, working in teams, develop interdisciplinary projects applying knowledge from all courses in each semester. A specific laboratory-project course coordinates an integrative project that aims to address complex problems. In the 2nd semester, two computer engineering courses (object-oriented programming and software engineering), and two mathematics courses (discrete mathematics and statistics) are involved, besides the laboratory/project course. This paper focuses on the integration of mathematics with informatics courses in this project, addressing real-world-like problems, bridging software engineering with mathematical topics. To assess the adopted PBL, enquiries were carried out among students. This approach fosters active learning and reinforces the relevance of mathematics within engineering, preparing students for job market demands. © 2026, IGI Global Scientific Publishing. All rights reserved.

2025

Do We Need 3D to See? Impact of Dimensionality of the Virtual Environment on Attention

Authors
Matos, T; Mendes, D; Jacob, J; de Sousa, AA; Rodrigues, R;

Publication
2025 IEEE CONFERENCE ON VIRTUAL REALITY AND 3D USER INTERFACES ABSTRACTS AND WORKSHOPS, VRW

Abstract
Virtual Reality allows users to experience realistic environments in an immersive and controlled manner, particularly beneficial for contexts where the real scenario is not easily or safely accessible. The choice between 360 content and 3D models impacts outcomes such as perceived quality and computational cost, but can also affect user attention. This study explores how attention manifests in VR using a 3D model or a 360 image rendered from said model during visuospatial tasks. User tests revealed no significant difference in workload or cybersickness between these types of content, while sense of presence was reportedly higher in the 3D environment.

2025

Understanding wind Energy Economic externalities impacts: A systematic literature review

Authors
Ramalho, E; Lima, F; López-Maciel, M; Madaleno, M; Villar, J; Dias, MF; Botelho, A; Meireles, M; Robaina, M;

Publication
RENEWABLE & SUSTAINABLE ENERGY REVIEWS

Abstract
Electricity generation from wind energy is one of the main drivers of decarbonization in energy systems. However, installing wind farm facilities may have beneficial and harmful impacts on the habitat of living beings. This study reviews the literature based on economic analysis to identify the main externalities related to the installation of wind farms and the economic methodologies used to assess these externalities, filling an existent literature gap. A systematic literature review followed the Preferred Reporting Items on Systematic Reviews and Meta-analysis standards. A total of 33 studies were identified, most of them carried out in Europe. The studies cover 24 years, between 1998 and 2022. The externalities associated with wind electricity generation are classified into three categories: the impact on well-being, the impact of wind turbines, and the impacts of avoided externalities. Most studies (24 out of 33) determine economic values by stated preference methods through choice experiments, discrete choice experiments, and contingent valuation. Revealed preference methods were identified in 5 studies using hedonic pricing and travel cost techniques. The challenges and limitations of this analysis in terms of externalities identification and their assessment are also discussed, concluding that additional updated review studies are needed since the latest ones were published in 2016 and 2017. Moreover, it gives insights to policymakers and academics on a more complete approach they can use to evaluate the impacts of decarbonization, which, apart from the technological view, also considers and estimates the socio-economic and environmental perspectives.

2025

A new proposed model to assess the digital organizational readiness to maximize the results of the digital transformation in SMEs

Authors
Silva, RP; Mamede, HS; Santos, V;

Publication
JOURNAL OF INNOVATION & KNOWLEDGE

Abstract
Scientific research in digital transformation is expanding in scope, quantity, and relevance, bringing forth diverse perspectives on which factors and specific dimensions-such as organizational structure, culture, and technological readiness-affect the success of digital transformation initiatives. Numerous studies have proposed mechanisms to assess an organization's maturity through digital transformation across various models. Some of these models focus on external influences, others on internal factors, or both. Although these assessments provide valuable insights into a company's transformation state, they often lack consistency, and recent research highlights key gaps. Specifically, many models primarily reflect the views of senior management on the general progress of digital transformation rather than on measurable outcomes. Moreover, these models tend to target large enterprises, overlooking small and medium enterprises (SMEs), which are crucial to economic growth yet face unique challenges, such as limited resources and expertise. Our study addresses these gaps by concentrating on SMEs and introducing a novel approach to assessing digital transformation readiness-a metric that reflects how prepared an organization is to optimize transformation outcomes. Following design science research methodology, we develop a model that centers on the perspectives of general employees, offering companies an in-depth view of their readiness across 20 dimensions. Each dimension is evaluated through behaviors indicative of the highest level of digital transformation readiness, helping companies identify areas to maximize potential benefits. Our model focuses not on technological quality but on the degree to which behaviors essential for leveraging technology and innovative business models are integrated within the organization.

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