ESTG - Artigos em revistas internacionais
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- Shallow and deep learning approaches to classify melanoma and non-melanocytic skin lesionsPublication . Spolaôr, Newton; Lee, Huei Diana; Takaki, Weber Shoity Resende; Mendes, Ana Isabel Gonçalves; Fonseca-Pinto, Rui; Nogueira, Conceição Veloso; Coy, Claudio Saddy Rodrigues; Wu, Feng ChungSeveral image processing methods in Dermatology are grounded in shallow and deep learning approaches. These solutions are relevant to assist health experts in decision-making processes related to harmful melanoma—a malignant melanocytic condition—and other skin lesions. This work aims to compare these approaches in a specific classification problem: malignant melanocytic lesions versus non-melanocytic ones. We developed 39 learning method configurations, including three original ones based on fine-tuned deep neural networks. Some implemented settings incorporate auxiliary procedures, such as oversampling, feature selection and data augmentation. An experimental evaluation in the public Derm7pt dermoscopic database suggests that the best original setting performance was competitive against the leading results reported by recent literature alternatives. In particular, the proposal reached average accuracy and sensitivity of 0.9909 and 0.9976, respectively. These results were averaged across three runs of the stratified nested cross-validation strategy. Moreover, our 39 configurations outperformed an experimental baseline derived from the majority class error. Thus, this work can be helpful in inspiring computational systems that could act as preliminary filters to support the detection of a harmful form of skin cancer and its separation from other lesions.
- Integrating Internet of Things into cardiac rehabilitation for heart failure: a review of emerging technologiesPublication . Klein, Adriana; Pinheiro, Rafael; Fonseca-Pinto, RuiHeart failure (HF) is a prevalent and debilitating condition that significantly affects patients' quality of life and places a substantial burden on healthcare systems. In recent years, digital technologies have been increasingly explored in cardiac rehabilitation (CR), particularly through their integration within Internet of Things (IoT) ecosystems to support remote monitoring and personalized care. This review aimed to provide a focused overview of emerging digital technologies applicable to the rehabilitation of patients with HF, with emphasis on solutions compatible with IoT-based systems. A targeted literature search was conducted in PubMed, Scopus, Cochrane and Web of Science, including studies published between 2019 and 2024. Studies addressing digital technologies in HF rehabilitation. Following a structured selection process, 59 articles were included in the narrative synthesis. The findings indicate a growing body of literature investigating wearable physiological monitoring devices, telehealth-based CR programs, digital platforms, and smart sensors, many of which have been explored for integration within IoT infrastructures. These technologies have been associated with improved remote follow-up, patient engagement, and real-time physiological data collection outside traditional clinical settings. Emerging applications of artificial intelligence within IoT-enabled systems have also been examined to support clinical workflows and adaptive rehabilitation strategies. Despite increasing interest, challenges remain, including heterogeneity in study designs, usability concerns, data privacy and security issues, economic barriers, and limited large-scale clinical validation. Overall, this review suggests that IoT-enabled technologies represent a promising area of research in CR, warranting further investigation to support their sustainable integration into routine HF care.
- Optimization of Anti-Spam Systems with Multiobjective Evolutionary AlgorithmsPublication . Basto-Fernandes, Vitor; Yevseyeva, Iryna; Méndez, José R.In this paper anti-spam filtering is presented as a cumbersome service, as opposed to a software product perspective. The huge human effort for setting up, adaptation, maintenance, and tuning of filters for spam detection in anti-spam systems is explained. Choosing the best importance scores for the spam filters is essential for the accuracy of any rules based anti-spam system, and is also one of the biggest challenges in this research area. Optimal filters score settings for Apache SpamAssassin project (the most widely adopted anti-spam open-source software) is addressed. In addition to a survey done on single/multi-objective optimization research in this area, we also present a study for filters score setting using multiobjective optimization based on two most representative evolutionary algorithms, NSGA II and SPEA2. Problem description, simulation and results analysis is done for SpamAssassin public mail corpus which is widely used for benchmarking purposes.
- Abordagem baseada em Algoritmos Genéticos para deteção de vulnerabilidades de SQL Injection em Aplicações Web PHPPublication . Baptista, Kevin; Bernardino, Anabela Moreira; Bernardino, Eugénia MoreiraHoje em dia, existe uma maior preocupação com a segurança no desenvolvimento de aplicações web. No entanto, ainda existem muitos ataques a este tipo de aplicações, perpetuados por hackers que se aproveitam das vulnerabilidades destas aplicações. Estas vulnerabilidades podem estar associadas a inúmeros fatores, desde configurações incorretas, falhas nas políticas de segurança, sistemas ou componentes desatualizados ou problemas diretamente associados ao código desenvolvido. Os ataques a aplicações web tem como resultado perda de informação privilegiada. Para mitigar este problema, existem varias ferramentas automatizadas que permitem auxiliar profissionais da área a identificar estas vulnerabilidades. No entanto, manter estas ferramentas atualizadas com a evolução tecnológica tem-se demonstrado um desafio. Neste artigo, propomos uma abordagem para detetar vulnerabilidades de SQL Injection no código-fonte de varias aplicações web PHP, usando Algoritmos Genéticos (AG). Os resultados obtidos mostram a eficiência do AG em relação a outras ferramentas existentes.
- Joint estimation using revealed and stated preference data: An application using a national forestPublication . Simões, Paula; Barata, Eduardo; Cruz, LuísWe combine contingent behaviour with travel cost data to estimate the change in the recreational use value of a National Forest due to quality and price changes. Instead of the usual improvement scenario, a hypothetical deterioration in the conditions of the forest due to a fire is considered. A dataset containing five observations for each respondent enabled the estimation of three models for which the number of scenarios differed. The results show that visitors are sensitive to price and quality changes and that in the forest fire scenario the intended number of trips would be reduced and that respondents would experience a welfare loss. Signs of inconsistency between preferences expressed by revealed and intended behaviour were found. This research also provides some indications that strategic bias affects answers to price changes.
- Prediction of multiaxial fatigue life of notched maraging steel components manufactured by selective laser meltingPublication . Branco, R.; Costa, J. D.; Jesus, J.; Berto, F.; Ferreira, J. A. Martins; Capela, C.This paper aims at predicting the fatigue crack initiation life in maraging steel manufactured by selective laser melting under in-phase bending-torsion loading. Three relationships between the bending moment and the torsion moment were studied, namely B/T=2, B/T=1, and B/T=2/3. The tested geometries consisted of hollow cylindrical specimens with lateral holes. The crack initiation and the crack paths were detected in-situ using a high-resolution digital camera. The local stress-strain states at the notch region were accounted for using two alternative numerical models developed within linear-elastic frameworks: (1) a parametric structured mesh; and (2) an automatic unstructured mesh. Fatigue crack initiation sites and fatigue crack initiation lives were successfully predicted using both numerical models.
- Overloading effect on transient fatigue crack growth of Ti-6Al-4V parts produced by Laser Powder Bed FusionPublication . Borrego, L. P.; Jesus, J. S.; Ferreira, J. A. M.; Costa, J. D.; Capela, C.The fatigue crack growth (FCGR) behavior of titanium alloy Ti-6Al-4V submitted to Hot Isostatic Pressing (HIP) through CT specimens manufactured by Laser Powder Bed Fusion (LPBF) is analyzed. Both the crack growth under constant amplitude loading and the transient crack growth behavior after the application of overloads were studied. Crack closure induced by plasticity for the stress ratio R=0 was observed at the Paris regime. The applied overloads for OLR=2 at R=0 caused a FCGR retardation due to the increase of crack closure effect induced by plasticity resulting from the overloads. Rapid transient periods were registered due to small zone affected by the overloads.
- Forensic age estimation using new models of mathematical regression formula constructed with molar indexes: dental age assessmentPublication . Pereira, Cristiana Palmela; Rodrigues, Ana; Augusto, Diana; Santos, Adriana; Salvado, Francisco; Santos, Rui; Cameriere, RobertoIntroduction: In forensic science, age estimation for identification purposes of living and deceased individuals, is of great importance. It is crucial for humanitarian reasons in both civil and criminal cases. Objectives: The aim of this study was to contribute to the process of forensic age estimation using dental age assessment with mineralization stages of Demirjian method, and maturity indexes of permanent mandibular second (I2M) and third molars (I3M). Material and methods: Two samples were used from a Portuguese population; for I2M, 591 orthopantomography’s aged between 7 and 15 years and for I3M, 350 orthopantomography’s aged between 12 and 23 years. Age estimation was obtained using linear regression models, each model was estimated with all observations and without observations, in which I2M or I3M = 0. Results: The results of ICC for intra and interobserver validation varied between 0.608 and 0.999 for both indexes. Pearson correlation coefficient between each index and chronological age showed that all indexes were significantly negatively correlated with chronological age. The standard error of estimate and the mean absolute error were continually low without patients with null index. Conclusions: Application of I2M is reproducible in a Portuguese population for medicallegal application in a population aged 7 to 15 years, when the corresponding index is positive. Third molar must be used only if its index is positive. The inclusion of Demirjian staging in both models significantly increases accuracy.
- Fatigue crack growth of TiAl6V4 parts produced by SLM under biaxial mode I/mode II loadingPublication . Borrego, L. P.; Jesus, J. S.; Ferreira, J. A. M.; Costa, J. D.; Capela, C.Mode I and mixed-mode fatigue crack growth tests were performed using compact tension shear specimens made of Ti-6Al-4V by additive manufacturing for various loading angles. The accuracy of the methodology used to determine the equivalent stress intensity factor was studied, obtaining good results in a simpler method and particularly when the crack deflection angle was included in the algorithm. The crack growth speed did not suffer significant alterations due to similar values of crack deflection angle, mode I loading predomination and similar crack closure effect. Fractured surfaces presented irregular regions consequence of intergranular separation between β phase and agglomerations of α phase.
- Special Issue on the International Conference on Health and Social Care Information Systems and Technologies 2012Publication . Cruz-Cunha, Maria Manuela; Rijo, Rui; Martinho, RicardoThis special issue of the International Journal of Healthcare Information Systems and Informatics integrates the enhanced versions of a selection of papers submitted and presented at HCist’2012 - International Conference on Health and Social Care Information Systems and Technologies, held in Algarve, Portugal last October 2012. It was the second edition of a conference where, under the leitmotiv of Healthcare Information Systems, academics, scientists, IT/IS professionals, managers and solution providers from all over the world had the opportunity to share experiences, bring new ideas, debate issues and introduce the latest developments.