ESTiG - Artigos em Revistas Não Indexados à WoS/Scopus
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- Interpretability analysis of deep models for COVID-19 detectionPublication . Silva, Daniel; Casanova, Edresson; Gris, Lucas; Gauy, Gustavo; Junior, Arnaldo; Finger, Marcelo; Svartman, Flaviane; Medeiros, Beatriz; Martins, Marcus; Aluísio, Sandra; Berti, Larissa; Teixeira, João PauloDuring the coronavirus disease 2019 (COVID-19) pandemic, various research disciplines collaborated to address the impacts of severe acute respiratory syndrome coronavirus-2 infections. This paper presents an interpretability analysis of a convolutional neural network-based model designed for COVID-19 detection using audio data. We explore the input features that play a crucial role in the model’s decision-making process, including spectrograms, fundamental frequency (F0), F0 standard deviation, sex, and age. Subsequently, we examine the model’s decision patterns by generating heat maps to visualize its focus during the decision-making process. Emphasizing an explainable artificial intelligence approach, our findings demonstrate that the examined models can make unbiased decisions even in the presence of noise in training set audios, provided appropriate preprocessing steps are undertaken. Our top-performing model achieves a detection accuracy of 94.44%. Our analysis indicates that the analyzed models prioritize high-energy areas in spectrograms during the decision process, particularly focusing on high-energy regions associated with prosodic domains, while also effectively utilizing F0 for COVID-19 detection.
- Reciclaje de residuos de envases: un impulso a la economía circular en la Península IbéricaPublication . Praça, Lídia GalvãoThis work fits into a Circular Economy context, as it aims to show the evolution of packaging waste recycling, which, according to EUROSTAT (Statistical Service of the European Union), can include wasted material that was used for containment, protection, handling, delivery and presentation of goods, from raw materials to processed products, from the producer to the user or consumer, excluding production waste. Therefore, based on data published by PORDATA (Database on contemporary Portugal and Europe) and INE (National Institute of Statistics), the amount of waste produced in the European Union per capita is high and has increased in recent years, but not in the same way for all member states, and there are even some, where there is a decrease compared to the European average. There are also differences in the way waste produced by each member state is managed and in meeting proposed community targets for recycling. In this sense, and as this is the first phase of exploratory work, with reference to the 2030 Agenda and respective SDGs, the study is based on the analysis of packaging waste produced and recycled in Portugal and Spain, since 1998, with the aim of complementing later with the enlargement to other member states of the European Union. At this stage, the study concluded that more is recycled in Spain than in Portugal and that as of 2011 the recycling rate is even higher than the average for European Union member states.
- Armazenamento de energia excedente: bateria ou hidrogeneo verde?Publication . Horn, Beatriz Souza; Soares, Orlando; Brito, Paulo SérgioNo projeto de uma usina fotovoltaica, pode-se sobredimensionar a potência dos módulos para maior aproveitamento da curva de geração. Porém, em momentos de pico de irradiância a curva de geração é cortada (clipping), o que resulta em energia não aproveitada. Este artigo compara a eficiência das soluções de baterias e de hidrogênio verde para o armazenamento desse excedente e sua posterior injeção na rede.
- Evaluation of supplier sustainable development programs using the HFLTS-QFD methodPublication . Guilherme, Kyu; Geraldes, Carla A.S. ; Junior, Francisco; Duarte, AnaObjective: This study proposes a decision model for evaluating sustainable supplier development programs (SSDPs) using the HFLTS-QFD technique, which is a combination of Hesitant Fuzzy Linguistic Term Sets (HFLTS) with the Quality Function Deployment (QFD) method. Theoretical Framework: The implementation of supplier development programs is important to improve supplier performance in aspects related to economic, environmental and social aspects. The evaluation of these programs is necessary to decide on their continuation or discontinuation, as well as to direct the allocation of resources. Method: The bibliographical research supported the definition of the requirements and criteria used for the evaluation of SDPs. The implementation of the model was done using MS Excel® software. The application in an illustrative case involving the evaluation of five SDPs allowed us to demonstrate the applicability of the model. Results and Discussion: The most relevant criteria were organization strategy, social responsibility, employee training and environmental management. The programs with the best classification were SDP4 and SDP5. Research Implications: The proposed model supports the selection of criteria considering their relative weights and the degree of difficulty in collecting data from suppliers when evaluating each PDFS. It also has the capacity to assist group decision-making, enabling the assignment of weights to decision-makers. Originality/Value: Unlike previous models for evaluating PDFS, which use economic or environmental criteria, the proposed model considers criteria related to the three dimensions of the Triple Bottom Line, in addition to allowing the use of linguistic expressions to deal with decisions under hesitation and uncertainty.
- Referência a mulheres cientistas – uma análise aos manuais escolares da disciplina de físico-química do 7º ano do ensino básicoPublication . Cardim, Sofia; Fernandes, Ana; Soares, SandraA escola exerce um papel fundamental na construção da identidade profissional das jovens estudantes relativamente às áreas STEM. Assumindo por base a questão de investigação “Existe sub-representação das mulheres nos manuais escolares da disciplina de Físico-Química do 7º ano?”, a presente investigação tem como objetivo analisar a menção a mulheres e cientistas mulheres nos manuais de Físico-Química do 7º ano do ensino básico, tratando-se de estudo exploratório da fase inicial de uma investigação de maior dimensão. Foram analisados dois manuais disponibilizados pelas editoras, no ano letivo 23/24, seguindo uma metodologia quantitativa, recorrendo à técnica de análise de conteúdo e análise estatística descritiva. Os resultados evidenciam uma total ausência da menção a cientistas mulheres nos manuais analisados, bem como uma sub-representação na maioria das categorias de análise consideradas.
- Decision support systems for lower limb rehabilitation using electrical stimulation—a reviewPublication . Franco, Tiago; Henriques, Pedro; Alves, Paulo; Pereira, Maria JoãoThis paper presents a comprehensive review of Decision Support Systems (DSS) for lower limb rehabilitation using Electrical Stimulation (ES), employing a rigorous two-part methodology. The first part involves a bibliometric analysis of articles from 1980 to 2023, while the second part is a systematic review of studies from 2019 to 2023, addressing six key research questions. The review identifies the main characteristics of DSS, such as data usage, sensitive data protection, reasoning techniques, and validation processes. It highlights the development focus on joint control systems, increasing interest in biofeedback and AI applications, and significant interest in FES-Cycling. Despite advancements, “decision support” remains in the early stages with simple architectures and limited data handling. Conversely, studies show advanced ES control models validated with neurological patients. This article emphasizes the need for sophisticated DSS that integrate data protection, reasoning methods, and patient monitoring to enhance rehabilitation outcomes and identifies significant gaps for future research.
- Evolution of inclusive education policies in PortugalPublication . Cardim, Sofia; Fernandes, Ana MaiaInclusive education in Portugal has undergone significant transformation over recent decades, driven byshifts in social, political, and legal frameworks that reflect a growing commitment to human rights and equalaccess to education. The movement from a historically segregated model to an integrated approa ch, catalysed by the Salamanca Declaration of 1994, has been pivotal in shaping contemporary educational practices. This study analyses how Portuguese policies on special needs education have evolved from the 1970s to the present and examines their impleme ntation in practice in compulsory education. The primary objectives are to analyse the impact of key legislative changes, particularly Decree Law 3/2008 and Decree Law 54/2018, on the inclusivity of the education system and to assess how these policies hav e been operationalized in schools. The findings reveal that while significant progress has been made in integrating students with special needs into mainstream education, challenges remain in achieving uniform implementation and in ensuring that all educat ional professionals are adequately prepared to support diverse learning needs. The shift towards a more flexible and personalized educational approach, as mandated by recent legislation and inspired by the Salamanca principles, marks a crucial step towards a more inclusive education system.
- Housing energy-related renovations based on perspectives on social and lifestyle standards: portuguese homeownersPublication . Lopes, Jorge; Oliveira, Rui; Abreu, Maria IsabelRecent studies have argued that energy-related renovations, which are not distinctive from other house improvements, must be socially contextualized and interwoven with householders’ daily social practices. Based on a practice-theory approach, this study explores how tastes, lifestyles and social values and norms can shape homeowners’ energy renovation practices. The study conducted semi-structured interviews with energy advisors and residents of owner-occupied housing in the North-eastern of Portugal, where purposive sampling techniques were used to manage participant selection. Results suggest that there are differentiated taste-motivated issues that could incentivize homeowners to renovate. This highlights the importance for public policy-makers to understand the diversity of homeowners’ desires and preferences regarding house renovation activities. Reflecting upon this diversity inside the household domain, gender differences reveal to be a significant factor in domestic energy management. These findings also corroborate those of previous works on how home renovation decisions reflect societal values and norms that determine “what would look nice” to have in a house, and why visible renovations (usually non-energy related) are often prioritized. An implication derived from these findings is that energy policies should be drawn in a way that portray energy efficiency in houses as fashionable as other consumer goods related with home design. These involve inter alia innovative partnerships between energy policy-makers and household products industries, home design magazines, marketing experts or real estate experts, which have the know-how to shape people’s tendencies and tastes.
- Atualizações de revisão de preços comparadas com custos reais de mercado(s) dos materiais: estudo de casoPublication . Oliveira, Rui; Abreu, Maria Isabel; Lopes, JorgeO controlo de custos de empreitadas exige metodologias de gestão cada vez mais ajustadas às especificidades das respetivas obras. Os consideráveis aumentos de custos de materiais, causados pela atual conjuntura de mercado global, exigem tomadas de decisão ajustadas à realidade. A revisão de preços aplicável às empreitadas de construção tem em consideração a atualização de preços com base nos índices atualizados de materiais, mão-de-obra e de equipamentos, onde, por vezes, não compensam a efetiva subida desses preços. A recente legislação (Decreto-Lei 36/2022) que alterou o regime jurídico de revisão de preços contempla a possibilidade de os cocontratantes interessados apresentarem correção ou alteração da fórmula de revisão de preços, quando a apresentada esteja desajustada às especificidades da empreitada ou quando a mesma esteja omissa no caderno de encargos. O artigo envolve a simulação de um caso real de uma obra onde foi aplicada revisão de preços, fazendo-se a comparação entre a compensação retribuída ao empreiteiro atendendo ao preço de determinados materiais na data considerada base de cálculo, e a resultante da efetiva subida de preços desses materiais, sob a forma de diferentes cenários de revisão com base na recente legislação. Este estudo demonstra que, mantendo as fórmulas que servem de base ao cálculo da revisão de preços, o empreiteiro pode ter retribuições que podem ser suficientes para compensar as eventuais subidas de preços de mercado. Em oposição, a utilização de determinados ajustamentos da fórmula-tipo de revisão de preços pode revelar retribuições superiores aos custos reais de mercado dos materiais.
- A transformação digital e o seu impacto na profissão de contabilista: breves reflexões e algumas evidencias com recurso a um estudo de casoPublication . Pires, Amélia M.M.; Gonçalves, Alex G.A transição energética com vista à descarbonização e a mudança para comportamentos mais sustentáveis é influenciada pelo valor financeiro atribuído às emissões de gases com efeito de estufa. As licenças de emissão de carbono são transacionadas em mercados financeiros, dependendo o seu preço da relação entre a procura e a oferta. A compreensão do valor atribuído a este instrumento financeiro permite que os intervenientes do mercado possam gerir a sua atividade e riscos de um modo mais consciente. Este estudo pretende identificar os determinantes do preço das emissões de carbono na União Europeia, analisando o período compreendido entre 2020 e 2023, que incorpora dois abalos significativos nos mercados financeiros e no mercado energético (a pandemia COVID-19 e a guerra entre a Rússia e a Ucrânia). A crise energética resultante destes acontecimentos nos diversos mercados provocou uma subida acentuada nos preços da energia com impacto significativo no gás natural, que é uma das principais matérias primas na produção de energia elétrica europeia. O impacto significativo de ambos os eventos nos mercados energéticos e as mudanças de comportamentos oferecem espaço para que existam transformações na influência que algumas matérias-primas possuem sobre o preço das licenças de emissões de carbono. Com recurso a diferentes modelos econométricos, os resultados mostram que os principais determinantes do preço das emissões de carbono são os preços do carvão, do gás natural, e o próprio preço do carbono.