FE - Artigos de Revistas Internacionais com Arbitragem Científica

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Politics, power, and influence : defense industries in the post-cold war
(Multidisciplinary Digital Publishing Institute (MDPI), 2021-01) Dos Reis, João Carlos Gonçalves; RCM2+ - Centro de Investigação em Gestão de Ativos e Engenharia de Sistemas
The post-Cold War era is placing the defense industry at a crossroads. If, on the one hand, it is under great pressure to guarantee warlike efforts around the world, with tight budgets and uncertain lead-times, on the other hand, it is seen as a central instrument for national sovereignty and foreign policy. The purpose of this research is to report the state-of-the-art of the existing literature and explore the most relevant research areas in order to provide the conceptual basis for further empirical research. To do so, this study uses a preferred reporting items for systematic review and meta-analysis (PRISMA), which is an adequate technique as it allows one to discover concepts, ideas, and debates about the defense industry. The results evidenced three different approaches to the defense industry—integration, autarky, and domination. In that regard, we present several case studies in which the defense industry is used as an instrument of foreign policy or national sovereignty. Future studies may focus on empirical research to validate the theoretical findings or to identify variables that lead some defense industries to seek synergies, resorting to mergers and acquisitions, while other defense companies prefer to obtain State funds.
Microfluidic bioreactors for enzymatic synthesis in packed-bed reactors—Multi-step reactions and upscaling
(Elsevier B.V., 2020-11-10) Brás, Eduardo J.S.; Domingues, Cristiana; Chu, Virginia; Fernandes, Pedro; Conde, João Pedro; HEI-LAB (FCT) - Digital Laboratories for Environments and Human Interactions
Enzymatic synthesis of biochemical commodities is of upmost importance as it represents a greener alternative to traditional chemical synthesis and provides easier downstream processing strategies compared to fermentation-based processes. A microfluidic system used to optimize the enzymatic production of both levodopa (L-DOPA) and dopamine in both single-step and multistep-reaction sequences with yield of approximately 30 % for L-DOPA production and 70 % for dopamine production is presented. The system for L-DOPA production was then up-scaled (780-fold increase) to a milliliter scale system by maintaining similar mass transport properties resulting in the same yield, space-time yield and biocatalyst yield as its microscale counterpart. The results obtained for yield and biocatalyst yield (351.7 mgL-DOPA mg−1Tyr h−1) were similar to what is reported in the literature for similar systems, however the space-time yield (0.806 mgL-DOPA L−1 h−1) was smaller. This work demonstrates a microfluidic bioreactor that can be used for complex optimizations that can be performed rapidly while reducing the consumption of reagents by immobilizing the catalyst on a carrier which can then be used in a packed-bed reactor, thus extending the enzyme life span.
Economic disposal quantity of leftovers kept in storage : a Monte Carlo simulation method
(De Gruyter Open Access, 2019) Assis, R.; Marques, Pedro Carmona; Santos, J. Oliveira; Vidal, R.; FE ¿ Faculty of Engineering
This article describes how to reach an item's threshold, or in other words, the limit time for it to be retrieved from stock and sold for a different use, as well as the remaining foreseen period for this situation to occur. Once a minimum length, or weight, is reached, left quantities are more difficult to sell, as demand often exceeds the remaining parts or leftovers. The number of unfulfilled orders increases, as time goes by, until it becomes further cost effective to dispose the leftover and sell it for a lower price and alternative use. A Monte Carlo simulation model was built in order to consider the randomness of future transactions and quantifying consequences providing this way a simple and effective decision-making framework.
Generating multidimensional clusters with support lines
(Elsevier B.V., 2023) Fachada, Nuno; de Andrade, Diogo; FE - Faculty of Engineering
Synthetic data is essential for assessing clustering techniques, complementing and extending real data, and allowing for more complete coverage of a given problem’s space. In turn, synthetic data generators have the potential of creating vast amounts of data – a crucial activity when real-world data is at premium – while providing a well-understood generation procedure and an interpretable instrument for methodically investigating cluster analysis algorithms. Here, we present Clugen, a modular procedure for synthetic data generation, capable of creating multidimensional clusters supported by line segments using arbitrary distributions. Clugen is open source, comprehensively unit tested and documented, and is available for the Python, R, Julia, and MATLAB/Octave ecosystems. We demonstrate that our proposal can produce rich and varied results in various dimensions, is fit for use in the assessment of clustering algorithms, and has the potential to be a widely used framework in diverse clustering-related research tasks. Keywords: Synthetic data, Clustering, Data generation, Multidimensional data
Uavnoma : a UAV-NOMA Network Model under non-ideal conditions
(Ubiquity Press, 2022-10-19) Lima, Brena; Fachada, Nuno; Dinis, Rui; Costa, Daniel B.; Beko, Marko; COPELABS (FCT) - Centro de Investigação em Computação Centrada nas Pessoas e Cognição (CTS)
Uavnoma is a set of Python functions and a front-end script for modeling, studying, and analyzing the communication system composed by an unmanned aerial vehicle (UAV) and two ground users. We assume that the UAV acts as an aerial base station to serve the users according to non-orthogonal multiple access (NOMA) principles. For more practical insights, residual hardware impairments (RHI) and imperfect successive interference cancellation (ipSIC) are considered. More specifically, uavnoma allows the modelers to study and visualize the system performance in terms of achievable rate and outage probability. Additionally, the package produces figures and tables showcasing results from the specified performance metrics. KEYWORDS: Non-orthogonal multiple access (NOMA); Non-ideal conditions; Numerical simulation; Performance analysis; Unmanned aerial vehicle (UAV)
Where are smart cities heading? A meta-review and guidelines for future research
(Multidisciplinary Digital Publishing Institute (MDPI), 2022-08) Reis, João; Marques, Pedro Alexandre; Marques, Pedro Carmona; RCM2+ - Centro de Investigação em Gestão de Ativos e Engenharia de Sistemas
(1) Background: Smart cities have been gaining attention in the community, both among researchers and professionals. Although this field of study is gaining some maturity, no academic manuscript yet offers a unique holistic view of the phenomenon. In fact, the existing systematic reviews make it possible to gather solid and relevant knowledge, but still dispersed; (2) Method: through a meta-review it was possible to provide a set of data, which allows the dissemination of the main theoretical and managerial contributions to enthusiasts and critics of the area; (3) Results: this research identified the most relevant topics for smart cities, namely, smart city dimensions, digital transformation, sustainability and resilience. In addition, this research emphasizes that the natural sciences have dominated scientific production, with greater attention being paid to megacities of developed nations. Recent empirical research also suggests that it is crucial to overcome key cybersecurity and privacy challenges in smart cities; (4) Conclusions: research on smart cities can be performed as multidisciplinary studies of small and medium-sized cities in developed or underdeveloped countries. Furthermore, future research should highlight the role played by cybersecurity in the development of smart cities and analyze the impact of smart city development on the link between the city and its stakeholders.
Multi-enzyme systems in flow chemistry
(Multidisciplinary Digital Publishing Institute (MDPI), 2021) Fernandes, Pedro; de Carvalho, Carla C.C.R.; Faculdade de Engenharia
Recent years have witnessed a growing interest in the use of biocatalysts in flow reactors. This merging combines the high selectivity and mild operation conditions typical of biocatalysis with enhanced mass transfer and resource efficiency associated to flow chemistry. Additionally, it provides a sound environment to emulate Nature by mimicking metabolic pathways in living cells and to produce goods through the systematic organization of enzymes towards efficient cascade reactions. Moreover, by enabling the combination of enzymes from different hosts, this approach paves the way for novel pathways. The present review aims to present recent developments within the scope of flow chemistry involving multi-enzymatic cascade reactions. The types of reactors used are briefly addressed. Immobilization methodologies and strategies for the application of the immobilized biocatalysts are presented and discussed. Key aspects related to the use of whole cells in flow chemistry are presented. The combination of chemocatalysis and biocatalysis is also addressed and relevant aspects are highlighted. Challenges faced in the transition from microscale to industrial scale are presented and discussed
Integrating Product-Service Systems with New Business Models Definition for Manufacturing Industries
(IGI Global Publishing, 2014) Marques, Pedro C.; Cunha, Pedro F.; Faculdade de Engenharia; RCM2+ - Centro de Investigação em Gestão de Ativos e Engenharia de Sistemas
Nowadays, manufacturing companies are pressured to be competitive and innovative. Particularly this concerns the delivery of value to their customers. The assessment of the overall value chain, designed and implemented for a specific product and/or service, should be sustained by new business models (NBM), thus contributing to higher levels of customer satisfaction. Integrated product-services are assuming importance, allowing manufacturing companies to achieve longer and stable relationships with their customers. This requires, among other, organizational changes and novel methodologies for product-service development. In fact, an effective integration allows product-service innovation, which being exploited, contributes significantly to businesses' competitiveness and sustainability. In this paper, a "roadmap" for NBM definition and implementation is presented, along with a new methodology for Product-Service Systems (PSS) development. Two case studies are used to test both the roadmap and the PSS methodology. As such, this work is expected to contribute to a clear understanding of NBM and their integration in a methodology for PSS.
Retail system scenario modeling using fuzzy cognitive maps
(Multidisciplinary Digital Publishing Institute (MDPI), 2022) Petukhova, Alina; Fachada, Nuno; FE - Faculty of Engineering
A retail business is a network of similar-format grocery stores with a sole proprietor and a well-established logistical infrastructure. The retail business is a stable market, with low growth, limited customer revenues, and intense competition. On the system level, the retail industry is a dynamic system that is challenging to represent due to uncertainty, nonlinearity, and imprecision. Due to the heterogeneous character of retail systems, direct scenario modeling is arduous. In this article, we propose a framework for retail system scenario planning that allows managers to analyze the effect of different quantitative and qualitative factors using fuzzy cognitive maps. Previously published fuzzy retail models were extended by adding external factors and combining expert knowledge with domain research results. We determined the most suitable composition of fuzzy operators for the retail system, highlighted the system’s most influential concepts, and how the system responds to changes in external factors. The proposed framework aims to support senior management in conducting flexible long-term planning of a company’s strategic development, and reach its desired business goals. Keywords: retail; complex systems; fuzzy cognitive maps; scenario planning
Procedural generation of 3D maps with snappable meshes
(Institute of Electrical and Electronics Engineers Inc., 2022-04-20) Silva, Rafael Castro e; Fachada, Nuno; Andrade, Diogo de; Códices, Nélio; FE - Faculty of Engineering
In this paper we present a technique for procedurally generating 3D maps using a set of premade meshes which snap together based on designer-specified visual constraints. The proposed approach avoids size and layout limitations, offering the designer control over the look and feel of the generated maps, as well as immediate feedback on a given map’s navigability. A prototype implementation of the method, developed in the Unity game engine, is discussed, and a number of case studies are analyzed. These include a multiplayer game where the method was used, together with a number of illustrative examples which highlight various parameterizations and piece selection methods. The technique can be used as a designer-centric map composition method and/or as a prototyping system in 3D level design, opening the door for quality map and level creation in a fraction of the time of a fully human-based approach. INDEX TERMS : 3D maps, computer games, designer-centric methods, layout, procedural content generation (PCG).
Capacitação social – comunidades em território de risco
(2018-04) Santos, Isabel Abreu dos; Vasconcelos, Lia Maldonado Teles de; Pires, Iva; Faculdade de Engenharia
Vivemos numa sociedade em que os cidadãos enfrentam uma multiplicidade de riscos, de diversas naturezas e níveis de complexidade, e na qual a elevada ocorrência de acidentes afeta a estrutura social das comunidades, a saúde humana e o ambiente natural e edificado. Há uma crescente consciencialização da necessidade de dar resposta a estas situações. O principal desafio da investigação é o de verificar se a prática de exercícios à escala real, envolvendo autoridades, decisores, academia e as pessoas, permite uma melhor preparação para as ações individuais e coletivas de prevenção e atuação face à ocorrência de um desastre. A metodologia aplicada baseou-se na análise de estudos de caso, com observação e participação de quatro exercícios LIVEX, simulacros realizados à escala real, entre 2012 e 2015, numa comunidade portuguesa, localizada em território de risco. Os exercícios referiram-se a um cenário de risco tecnológico (acidente industrial) e três cenários de risco natural (sismo). A análise de resultados do estudo, permitiu testar a participação das populações, a utilização de equipamentos, e as relações institucionais de resposta à emergência (nomeadamente as comunicações). Possibilitou ainda inferir que a forma mais eficiente de aprender é pela experiência, no individual ou no coletivo. As conclusões permitem afirmar que a prática de realização de exercícios LIVEX contribuem para a construção de conhecimento, geração de confiança nas instituições e profissionais, na comunicação de ciência, levando ao empoderando das pessoas para tomarem as decisões mais acertadas em face de situações limite em que a sua vida e dos seus familiares se pode encontrar em perigo. Setúbal, pela prática continuada de modelos de participação ativa em exercícios à escala real, pode vir a constituir uma comunidade de prática, um exemplo tipo a ser replicado por outras comunidades.
A igualdade de género na União Europeia : a implementação da agenda mulheres, paz e segurança
(Associacao Iberica de Sistemas e Tecnologias de Informacao, 2022-04) Malheiro, Luís; Menezes, Sofia; Reis, João; Machado, Paulo; Romão, Ana; Bessa, Fernando; RCM2+ - Centro de Investigação em Gestão de Ativos e Engenharia de Sistemas
A presente investigação versa sobre a promoção da igualdade de género conceitos estruturantes que permitiram desenhar o modelo analítico criado para dar espectro da segurança da União Europeia, que apresentam diversos níveis de de implementação da agenda, ao nível institucional, para promoção da mudança sendo crucial: explicitar a igualdade nos documentos internos e nos objetivos para o dirigente máximo; estabelecer regras sobre o respeito pela dignidade das mulheres e dos homens no local de trabalho; incluir a perspetiva de género no orçamento e alocar verbas; estabelecer o princípio da não discriminação e a promoção da os direitos e deveres dos trabalhadores sobre igualdade e não discriminação; planeamento estratégico; e delinear e levar a cabo um plano para implementar a agenda.
Digital transformation : a meta-review and guidelines for future research
(Elsevier Ltd., 2023-01) Reis, João; Melão, Nuno; RCM2+ - Centro de Investigação em Gestão de Ativos e Engenharia de Sistemas
The emergence of digital transformation has changed the business landscape for the foreseeable future. As scholars advance their understanding and digital transformation begins to gain maturity, it becomes necessary to develop a synthesis to create solid foundations. To do so, significant steps need to be taken to critically, rigorously, and transparently examine the existing literature. Therefore, this article uses a meta-review with the support of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Protocol. As a result, we identified six dimensions and seventeen categories related to digital transformation. The organizational, technological, and social dimensions are still pivotal in digital transformation, while two new dimensions (sustainability and smart cities) still need to be explored in the existing literature. The need to deepen knowledge in digital transformation and refine the dimensions found is of paramount importance, as it involves some complexity due to organizational dynamics and the development of new technologies. It was also possible to identify opportunities, challenges, and future directions.
MN-DS: A Multilabeled News Dataset for News Articles Hierarchical Classification
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-04-23) Petukhova, Alina; Fachada, Nuno; FE - Faculty of Engineering; COPELABS (FCT) - Centro de Investigação em Computação Centrada nas Pessoas e Cognição (CTS)
This article presents a dataset of 10,917 news articles with hierarchical news categories collected between 1 January 2019 and 31 December 2019. We manually labeled the articles based on a hierarchical taxonomy with 17 first-level and 109 second-level categories. This dataset can be used to train machine learning models for automatically classifying news articles by topic. This dataset can be helpful for researchers working on news structuring, classification, and predicting future events based on released news. Keywords: news dataset; text classification; NLP; media topic taxonomy
ParShift: a Python package to study order and differentiation in group conversations
(Elsevier B.V., 2023-12-01) Carvalho, João P. Matos; Fachada, Nuno; Pita, Manuel Arturo Marques; Saraiva, Bruno David Ferreira; Matos-Carvalho, João Pedro; COPELABS (FCT) - Centro de Investigação em Computação Centrada nas Pessoas e Cognição (CTS); CICANT (FCT) - Centro de Investigação em Comunicação Aplicada, Cultura e Novas Tecnologias; ECATI - School of Communication, Architecture, Arts and Information Technologies
Collective organization in multi-party conversations emerges through the exchange of utterances between participants. While most research has focused on content-centred mechanisms that lead to emergent conversational coordination, less attention has been given to explaining conversational order based on who is addressed and who responds, especially when dealing with large conversational datasets. In this paper, we introduce a Python library, ParShift, that implements a state-of-the-art theoretical quantitative framework known as Participation Shifts. This framework enables researchers to study participant-centred order and differentiation in multi-party conversations. With ParShift, researchers can characterize conversations by quantifying the probabilities of events related to how people address each other during conversations. This library is particularly useful for studying conversation threads in social networks, parliamentary debates, team meetings, or student debates on a large scale. Keywords: Small groups Social interaction Participation shifts Interpersonal coordination Turn-taking Emergent social behaviour
A rapid review on the use of free and open source technologies and software applied to precision agriculture practices
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-03-24) Santos, Rogério P. dos; Fachada, Nuno; Beko, Marko; Leithardt, Valderi; FE - Faculty of Engineering; COPELABS (FCT) - Centro de Investigação em Computação Centrada nas Pessoas e Cognição (CTS)
Technology plays a crucial role in the management of natural resources in agricultural production. Free and open-source software and sensor technology solutions have the potential to promote more sustainable agricultural production. The goal of this rapid review is to find exclusively free and open-source software for precision agriculture, available in different electronic databases, with emphasis on their characteristics and application formats, aiming at promoting sustainable agricultural production. A thorough search of the Google Scholar, GitHub, and GitLab electronic databases was performed for this purpose. Studies reporting and/or repositories containing up-to-date software were considered for this review. The various software packages were evaluated based on their characteristics and application formats. The search identified a total of 21 free and open-source software packages designed specifically for precision agriculture. Most of the identified software was shown to be extensible and customizable, while taking into account factors such as transparency, speed, and security, although some limitations were observed in terms of repository management and source control. This rapid review suggests that free and open-source software and sensor technology solutions play an important role in the management of natural resources in sustainable agricultural production, and highlights the main technological approaches towards this goal. Finally, while this review performs a preliminary assessment of existing free and open source solutions, additional research is needed to evaluate their effectiveness and usability in different scenarios, as well as their relevance in terms of environmental and economic impact on agricultural production.
Inulinase from Rhodotorula mucilaginosa : immobilization and application in the production of fructooligosaccharides
(The Korean Society of Food Science and Technology, 2021-07) de Araujo Ribeiro, Geise Camila; Fernandes, Pedro; Silva, Dayse Alessandra Almeida; Brandão, Hugo Neves; de Assis, Sandra Aparecida; Faculdade de Engenharia
The crude extract containing inulinase from Rhodotorula mucilaginosa was obtained by submerged fermentation. Inulinase was immobilized on chicken eggshell by physical adsorption and covalent crosslinking, using glutaraldehyde as a crosslinking reagent, and Celite by adsorption. Fructooligosaccharides production was performed using immobilized inulinase (5%, w/v) and inulin substrate solution under experimental conditions evaluated through Doehlert experimental design. The production of inulinase was optimized for concentrations of D-glucose and yeast extract at 12.5 and 0.5 g/L, respectively, resulting in an optimal activity of 0.62 U. The optimal pH and temperature for enzyme activity were 8.0 and 75 °C, respectively, leading to an optimal activity of 3.54 U. The highest immobilization efficiency (46.27%) was obtained upon immobilization on Celite. Immobilization by adsorption to eggshell allowed for specific activity of 4.15 U/g, and adsorption to Celite resulted in specific activity of 3.70 U/g. The highest titer in fructooligosaccharides was obtained with an initial inulin concentration of 250 g/L (25%, w/v), and a reaction time of 16 h. Hence, immobilized inulinase proved to be a promising catalyst for fructooligosaccharides production since the formulation is performed through a simple, low-cost, and large-scale applicable methodology.
Comparing Freshman and doctoral engineering students in design : mapping with a descriptive framework
(Taylor and Francis Ltd., 2017-11-02) Carmona Marques, P.; Faculdade de Engenharia
This paper reports the results of a study of engineering students’ approaches to an open-ended design problem. To carry out this, sketches and interviews were collected from 9 freshmen (first year) and 10 doctoral engineering students, when they designed solutions for orange squeezers. Sketches and interviews were analysed and mapped with a descriptive ‘ideation framework’ (IF) of the design process, to document and compare their design creativity (Carmona Marques, P., A. Silva, E. Henriques, and C. Magee. 2014. “A Descriptive Framework of the Design Process from a Dual Cognitive Engineering Perspective.” International Journal of Design Creativity and Innovation 2 (3): 142–164). The results show that the designers worked in a manner largely consistent with the IF for generalisation and specialisation loops. Also, doctoral students produced more alternative solutions during the ideation process. In addition, compared to freshman, doctoral used the generalisation loop of the IF, working at higher levels of abstraction. The iterative nature of design is highlighted during this study–a potential contribution to decrease the gap between both groups in engineering education.
A descriptive framework of the design process from a dual cognitive-engineering perspective
(Taylor and Francis, 2014) Marques, Pedro D.B.Carmona; Silva, Arlindo José P.F.; Henriques, Elsa M.P.; Magee, Christopher L.; Faculdade de Engenharia
This article proposes a new descriptive framework, which we label as the “ideation framework” (IF), of the design process from a dual cognitive-engineering perspective, partly based on existing frameworks from both fields and previous work by the author. The framework is for the ideation or front-end phase of the product development process, representing the interface between cognitive psychology and engineering design. Three domains – inspiration, decomposition, and integration – and three spaces – problem-space, idea-space, and concept-space – are the elements of the framework. The iterative flow of the engineering design process passes through the three domains in a semi-controlled way, through a sequence of specialization and generalization process loops in and between the spaces. An empirical descriptive examination of the ideation process is performed using designers with limited design experience. The designers were faced with a design problem that they had to solve in a limited period of time. Their designs were analyzed, and a post-exercise interview was done to uncover each of the participants’ design process. The empirical work indicates these designers worked in a manner largely consistent with the IF.
Improvement of aglycone content in soy isoflavones extract by free and immobilized β-Glucosidase and their effects in lipid accumulation
(Springer, 2020-11-01) Angelotti, Joelise A.F.; Dias, Fernanda F.G.; Sato, Hélia H.; Fernandes, Pedro; Nakajima, Vânia M.; Macedo, Juliana; Faculdade de Engenharia
Soybean is one of the most important commodities in the world, being applied in feed crops and food, pharmaceutical industries in different ways. Soy is rich in isoflavones that in aglycone forms have exhibited significant anti-obesity and anti-lipogenic effects. Obesity is a global problem as several diseases have been related to this worldwide epidemic. The aim of this work was to verify the effect of free and immobilized β-glucosidase, testing Lentikats, and sol–gel as carriers. Moreover, we wanted to examine if the different types of hydrolysis would generate extracts with distinct biological activity concerning lipid accumulation, PPAR-α regulation, and TNF-α, IL-6, and IL-10 concentrations using in vitro assays. Our results show that all formulations of β-glucosidase could hydrolyze soy isoflavones. Thus, after 24 h of incubation, daidzein content increased 2.6-, 10.8-, and 12.2-fold; and genistein content increased 11.7, 11.4, and 11.4 times with the use of free enzyme, Lentikats®, and sol–gel immobilized enzyme, respectively. Moreover, both methodologies for enzyme immobilization led to promising forms of biocatalysts for application in the production of soy extracts rich in isoflavones aglycones, which are expected to bring about health benefits. A mild lipogenic effect was observed for some concentrations of extracts, as well as a slight inhibition in PPAR-α expression, although no significant differences were noticeable in the cytokines TNF-α, IL-10, and IL-6 as compared with the control.

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