ESTiG - Resumos Indexados à WoS/Scopus
URI permanente para esta coleção:
Navegar
Entradas recentes
- Diabetic retinopathy grading using blended deep learningPublication . Monteiro, Fernando C.Diabetic retinopathy is a complication of diabetes that is mainly caused by the damage of the blood vessels located in the retina. Retinal screening contributes to early detection and treatment of diabetic retinopathy. DR has five stages, namely healthy, mild, moderate, severe and proliferative diabetic retinopathy. Computer-aided diagnosis approaches are needed to allow an early detection and treatment. Several automated deep learning (DL) based approaches have been proven to be a powerful tool for DR grading. However, these approaches are usually based on one DL architecture only which could produce over-fitted results. Another identified problem is the use of imbalanced datasets. In this paper, we proposed a blended deep learning approach obtained by training several individual DL models, using a 5-fold cross-validation technique and combining their predictions in a final score. This blended model highlights each individual model where it performs best and discredits where it performs poorly, increasing the robustness of the results. The experiments were conducted on a balanced DDR dataset containing 33310 retina fundus images equally distributed for the DR grades. An explainability algorithm was also used to show the efficiency of the proposed approach in detecting DR signs.
- Evaluation and characterization of the built rural environment of the Montesinho natural park, Portugal. The inhavit projectPublication . Luso, Eduarda; Ferreira, DéboraIn Portugal, in recent decades, there has been an increase in the population and cities located on the coast and, on the contrary, a decrease in inland locations, with greater severity in rural areas. The causes are complex and not consensual, but it is clear that factors such as the lack of investment in the interior, emigration and migration to a coast that is increasingly autistic in its relationship with the rest of the territory, the abandonment of agriculture and aging of the population constitute sufficient ingredients to promote the desertification of some areas of the country. The abandonment and desertification of villages is not just a problem in Portugal, however. Although Portugal is one of the countries most affected by this problem that affects the entire national territory, it is a European problem that has been increasing since the second half of the 20th century. Concerned about this fact, which puts at risk the high level of abandonment of villages and places in the interior of Portugal, particularly those located in the northeast of Trás-os-Montes, the InHaVit Project - Sustainable approaches for the rehabilitation and revitalization of the cultural heritage built in the Montesinho Natural Park ( PNM), funded by FCT – Fundação de Ciência e Tecnologia, has as its main objective the evaluation and characterization of: (1) the rural built environment of the PNM, at the level of buildings and at the level of villages; and (2) socioeconomic and environmental factors that contribute to the vulnerability of PNM villages and vernacular architecture. In-depth knowledge of these aspects will help to understand the reasons why the villages were progressively abandoned. In the end, the project will propose strategies for risk mitigation, rehabilitation and conservation of built heritage, recognizing that the appreciation and preservation of vernacular architecture is a key element of cultural identity and that it can become a privileged factor for local development. This article aims to show the work methodology relating to the “in-situ” survey carried out so far, relating to point (1), as well as some very particular aspects of this region, namely the slate roofs and the water mills.
- Evaluation and characterization of the built rural environment of the Montesinho Natural Park, Portugal. The inhavit projectPublication . Luso, Eduarda; Ferreira, DéboraIn Portugal, in recent decades, there has been an increase in the population and cities located on the coast and, on the contrary, a decrease in inland locations, with greater severity in rural areas. The causes are complex and not consensual, but it is clear that factors such as the lack of investment in the interior, emigration and migration to a coast that is increasingly autistic in its relationship with the rest of the territory, the abandonment of agriculture and aging of the population constitute sufficient ingredients to promote the desertification of some areas of the country. The abandonment and desertification of villages is not just a problem in Portugal, however. Although Portugal is one of the countries most affected by this problem that affects the entire national territory, it is a European problem that has been increasing since the second half of the 20th century. Concerned about this fact, which puts at risk the high level of abandonment of villages and places in the interior of Portugal, particularly those located in the northeast of Trás-os-Montes, the InHaVit Project - Sustainable approaches for the rehabilitation and revitalization of the cultural heritage built in the Montesinho Natural Park ( PNM), funded by FCT – Fundação de Ciência e Tecnologia, has as its main objective the evaluation and characterization of: (1) the rural built environment of the PNM, at the level of buildings and at the level of villages; and (2) socioeconomic and environmental factors that contribute to the vulnerability of PNM villages and vernacular architecture. In-depth knowledge of these aspects will help to understand the reasons why the villages were progressively abandoned. In the end, the project will propose strategies for risk mitigation, rehabilitation and conservation of built heritage, recognizing that the appreciation and preservation of vernacular architecture is a key element of cultural identity and that it can become a privileged factor for local development. This article aims to show the work methodology relating to the “in-situ” survey carried out so far, relating to point (1), as well as some very particular aspects of this region, namely the slate roofs and the water mills.
- Diatomaceous earth as a partial replacement for portland cement in mortars - a reviewPublication . Magalhães, Leandro; Gavilán, Ana; Ferreira, Débora; Merelles, SamiraOver the last years, the increase in CO2 emissions into the atmosphere, its impact on climate change, and issues related to the sustainability and environmental impacts generated by the participation of the construction industry in global warming, have led to countless researches, several of them looking to modernize cement production with alternative binders. The most known alternative binders used nowadays in the construction industry are slag obtained in blast furnaces, metakaolin and fly ashes obtained from burning coal in thermoelectric power stations. In the present paper, due to diatomaceous earth’s pozzolanic properties, is researched the possibility of the use of diatomaceous earth as an alternative binder. This work shows a review of studies about introduction of raw and calcined diatomaceous earth in cement mortars, and the feasibility of using this material as a binder in cement mortars. The different studies present that the introduction of different percentages of diatomaceous earth in mortars influences the physical and mechanical characteristics of the manufactured mortars. The tests performed in mortars with introduction of calcined diatomaceous earth show that the mechanical strength improves when compared to mortars manufactured with raw diatomaceous earth. The results of the compressive and flexural strength in mortars with introduction of calcined diatomaceous earth present lower values during the first 28 days, when compared with mortars without diatomaceous earth, however, there is a significant increase in the values of mechanical resistance, surpassing the values of mechanical resistance of mortars without diatomaceous earth at the end of 90 days. The water absorption by immersion tests also reveal that the increased introduction of diatomaceous earth increases the water absorption of the mortars.
- Evaluation and characterization of the built rural environment of the Montesinho natural park, Portugal. the inhavit projectPublication . Luso, Eduarda; Ferreira, DéboraIn Portugal, in recent decades, there has been an increase in the population and cities located on the coast and, on the contrary, a decrease in inland locations, with greater severity in rural areas. The causes are complex and not consensual, but it is clear that factors such as the lack of investment in the interior, emigration and migration to a coast that is increasingly autistic in its relationship with the rest of the territory, the abandonment of agriculture and aging of the population constitute sufficient ingredients to promote the desertification of some areas of the country. The abandonment and desertification of villages is not just a problem in Portugal, however. Although Portugal is one of the countries most affected by this problem that affects the entire national territory, it is a European problem that has been increasing since the second half of the 20th century. Concerned about this fact, which puts at risk the high level of abandonment of villages and places in the interior of Portugal, particularly those located in the northeast of Trás-os-Montes, the InHaVit Project - Sustainable approaches for the rehabilitation and revitalization of the cultural heritage built in the Montesinho Natural Park ( PNM), funded by FCT – Fundação de Ciência e Tecnologia, has as its main objective the evaluation and characterization of: (1) the rural built environment of the PNM, at the level of buildings and at the level of villages; and (2) socioeconomic and environmental factors that contribute to the vulnerability of PNM villages and vernacular architecture. In-depth knowledge of these aspects will help to understand the reasons why the villages were progressively abandoned. In the end, the project will propose strategies for risk mitigation, rehabilitation and conservation of built heritage, recognizing that the appreciation and preservation of vernacular architecture is a key element of cultural identity and that it can become a privileged factor for local development. This article aims to show the work methodology relating to the “in-situ” survey carried out so far, relating to point (1), as well as some very particular aspects of this region, namely the slate roofs and the water mills.
- The legal research methodology as a method for researching in business area: a case study applied to gymnasiumsPublication . Aldeia, Susana; Silva, Natacha Jesus; Nanez, SergioPurpose – The main objective of this paper is to understand how the analysis of laws and jurisprudence influences the decisions of gym managers in Portugal. Design/methodology/approach – For this purpose, the Portuguese tax law was investigated, particularly the Value Added Tax law and additional legal dispositions. It also researches the arbitral case law related to nutrition consulting in sports activity companies. Findings – The nutrition consultation is considered a medical act subject to the legal disposition of article 9º of the Value Added Tax Code, which means that when the medical service is provided by a professional, the beneficiary of the services can benefit from the VAT exemption. This disposition observes the European Union Directive 2006/112/EC of the European Council. Nevertheless, when a nutritionist provides these services through an entity that offers sports activities like gyms, some doubts are raised because it can be considered that nutritional monitoring has no therapeutic purpose. Customers could not benefit from the VAT exemption if some conditions were not observed. The arbitral tax court has been considering that it needs to keep some requirements for that exemption could be applied to the gym services. In several cases, fulfilling the conditions is complex and generates litigation between the Portuguese Tax Authority and gyms. In the personal sphere, there are two possibilities for the service's recognition i) if the service is recognized as a consultation, it could benefit as a medical expense in the personal income tax statement; ii) if it is not considered as a medical expense, each person can deduct 15% of the VAT in the same statement. Originality: This paper demonstrates the role that court rulings play in clarifying day-to-day issues for managers. It also shows that laws and court rulings are an essential source of data in management research. Research limitations/implications – This study only analyses the Portuguese case, it could be interesting to study other countries that do not apply the value-added tax law.
- Inclusion of bim methodology and open bim workflow in small engineering project officesPublication . Carvalho, Márcio; Oliveira, Rui; Rodrigues, HugoDevido às exigências técnicas e à crescente evolução das tecnologias no desenvolvimento de projetos de especialidades de engenharia, o BIM (Building Information Modeling) viu-se como uma ferramenta de enorme potencial de utilização. Porém para implementação desta metodologia, ainda se encontram muitas lacunas, principalmente em gabinetes de projetos de pequena dimensão, onde o processo de mudança para essa “nova era” da informação na construção ainda não é totalmente acessível e facilitado. Ainda é um desafio com problemas inerentes relacionados como a especialização e formação das partes interessadas do setor e o próprio custo inicial de investimento. Porém esses problemas podem ser sanados com planeamento ajustado a longo prazo, além do próprio custo, tempo e qualidade nos projetos desenvolvidos, a par de seguimento das exigências de mercado ao nível das novas tecnologias. Mesmo os técnicos que operam em BIM sentem dificuldades na adequação e ajuste para modelos bidimensionais convencionais e até mesmo em formato papel, ainda exigidos pelas entidades de licenciamento. Assim como essas entidades, que também não estão ajustadas à evolução da tecnologia BIM, recebendo projetos sem as devidas informações nos modelos 3D. Este artigo aborda uma pesquisa bibliográfica detalhada relacionada com os problemas e dificuldades de implementação em gabinetes de projetos da tecnologia BIM, mais especificamente o conhecimento prático em alguns gabinetes de engenharia. Pretende-se demonstrar no artigo algumas alternativas e potenciais soluções para facilitar na adequação e implementação da metodologia BIM em gabinetes de projetos de pequena dimensão, especificamente na área de projetos de especialidades. Tenciona-se ainda propor um workflow que envolva os projetistas, os gabinetes e até as entidades de licenciamento, de modo que os modelos 3D desenvolvidos em BIM possam ser explorados ao máximo, buscando a redução nas perdas de recursos e de informações enquanto as entidades de licenciamento não se atualizam para a análise dos projetos em formato BIM.
- Comparative study of construction options based on sustainability assumptionsPublication . Rivani, Maria L.A.; Oliveira, Rui; Ribeiro, Rodrigo S.O desenvolvimento sustentável é uma abordagem fundamentada no equilíbrio entre três dimensões, denominadas ambiental, social e económica, visando a satisfação de necessidades, sem comprometer as das populações futuras. Aplicada na construção civil, a sustentabilidade tem por intuito assegurar que nos processos de execução, reabilitação e demolição sejam utilizadas estratégias que diminuam os impactos ambientais, promovam a viabilidade económica e proporcionem qualidade de vida para as gerações. Perante essa permissa, o objetivo do estudo é realizar uma análise comparativa entre soluções construtivas que sejam detentoras de pressupostos de maior sustentabilidade e que atendam os requisitos mínimos de comportamento térmico, com o fim de procurar soluções viáveis que promovam menor impacto ambiental, que atendam as reduções de energia e de água incorporada e que contribuam para a redução de emissões de GEE. As opções construtivas selecionadas e alvo de estudo, foram analisadas a partir dos resultados coletados de diferentes categorias de impacto ambiental, tais como: GWP, ODP, AP, entre outros. Estudos bibliográficos foram realizados para sustentar a análise, além da consulta das DAP utilizadas em produtos de construção aplicados nas diferentes soluções estudadas. Os resultados baseiam-se numa proposta de solução para a reabilitação de uma edificação, que pode ser substituída por processos construtivos sustentáveis e termicamente eficientes, que são passíveis de aplicação.
- An insight into the adjustments for changes in costs formula for construction contracts attending real planningPublication . Oliveira, Rui; Abreu, Maria Isabel; Lopes, Jorge;A gestão de custos das empreitadas de construção tem exigido cada vez maior rigor, utilizando metodologias ajustáveis às diversidades das mudanças conjunturais. As flutuações de preços, sobretudo nas subidas de preços ao nível dos materiais de construção, por efeitos da instável conjuntura de mercado, exigem planeamento e tomadas de decisão que começam no projeto. Em muitos casos o planeamento é feito considerando apenas o presente, mas no decurso das obras surgem imprevistos e diversos fatores externos, que em muitos casos não permitem a nível burocrático mudanças processuais, desencadeando problemas de gestão e prejuízos. A revisão de preços aplicável às empreitadas atende à atualização de preços com base nos índices atualizados de materiais, mão-de-obra e de equipamentos, mas em determinadas fases da obra não compensam a real e efetiva subida dos preços de alguns materiais, pois é feita com base numa média entre os materiais mais significativos presentes na empreitada, distribuídos pelo prazo da empreitada. Há cerca de um ano foi criado o regime excecional aplicável à revisão de preços, e cuja aplicação foi prolongada até Dezembro deste ano e estendida a outras atividades. Esta alteração contempla a possibilidade de os interessados apresentarem correção ou alteração da aplicação do regime de revisão de preços, quando a vigente esteja desajustada às especificidades da empreitada ou quando a mesma seja omissa no caderno de encargos. O novo regime permite esse ajuste, mas futuramente tal poderá não ser possível, pelo que o desenho das fórmulas de revisão de preços deve atender a particularidades das obras e prever eventuais constrangimentos, podendo tirar-se ensinamentos com a atual inflação de preços. O artigo pretende apresentar fórmulas presentes em obras de empreitadas e a proposta de eventuais soluções, procedimentos e ajustes a essas fórmulas atendendo ao planeamento previsto para as mesmas, de modo que a sua aplicação no cálculo pelas fórmulas atenda aos materiais efetivamente aplicados em datas especificas, situação frequentemente negligenciada. O estabelecimento de comparações entre as diversas empreitadas objeto de estudo permitem conhecer as compensações financeiras aos empreiteiros nas diferentes situações estudadas, estendendo-se as comparações com a subida de preços ocorrida nos materiais.
- The application of lean construction solutions in site works of residential refurbishment projects: an overviewPublication . Missaoui, Ahmed; Abreu, Maria Isabel; Oliveira, RuiThe construction industry has long faced challenges of low productivity, high costs, and substantial waste. In recent years, Lean Construction has emerged as a promising solution to address these issues. This scientific article explores the principles of Lean Construction and investigates their application in building refurbishment projects. Specifically focusing on the context of building refurbishment, this article delves into the key concepts and tools of Lean Construction, such as Value Stream Mapping, Pull Planning, Just-in-Time Delivery, Last Planner System, and Visual Management. These tools enable the elimination of waste, improvement of project outcomes, increased productivity, and reduced costs. Moreover, this article presents the results of surveys and interviews conducted within the building refurbishment sector, examining the implementation of Lean Construction practices. The findings illustrate the potential benefits of Lean Construction in enhancing project delivery, reducing costs, and improving overall project outcomes. Based on these insights, practical recommendations are provided for the successful implementation of Lean Construction solutions in building refurbishment projects, including the importance of leadership, stakeholder collaboration, continuous improvement, and the use of data and metrics to measure progress. This article contributes to the knowledge base on Lean Construction, providing guidance for the development of building refurbishment projects and serving as a catalyst for further research in this field.