2024
Autores
Dias, BS; de Almeida, JMMM; Coelho, LCC;
Publicação
IEEE SENSORS JOURNAL
Abstract
The excitation of two different electromagnetic surface waves-surface plasmon polaritons (SPPs) and Bloch surface waves (BSWs)-is demonstrated in a 1-D metal-dielectric photonic crystal with numerical and experimental studies. The discussed structure consists of an Ag-TiO2 thin-film stack forming a metal-insulator-metal-insulator device. The thickness of the TiO2 layer placed between the metals is tested for two different values (50 and 300 nm), which also allows the excitation of guided-mode resonances. It is observed that BSWs in this metal-dielectric structure behave similar to the case of all-dielectric photonic crystals, whereas the SPP modes display similar properties to those excited in metal-insulator-metal cavities. The sensitivity of these surface states to variations in the refractive index (RI) of the external dielectric is characterized. For the case of the plasmonic modes, a maximum sensitivity of (7.2 +/- 0.3) x 10(3) nm/RIU was measured, while for the BSW the maximum sensitivity was (1.20 +/- 0.05) x 10(2) nm/RIU. Due to the large field enhancement and penetration on external media, these surface states display exceptional properties for application in optical sensors, and the presented results provide interesting possibilities in the design of novel sensing structures with a flexible selection of surface states for interrogation.
2024
Autores
Pequeno, JT; Fonseca, B; Lopes, JBO;
Publicação
INTERNATIONAL JOURNAL OF TECHNOLOGY AND DESIGN EDUCATION
Abstract
This work aims to identify teaching and learning practices in practical classes of Computer Network Technology courses, which promote the use of the Physical Laboratory (PL) as an epistemic tool to improve learning in epistemic terms. Content analysis of Multimodal Narrations (MN) of three classes by two teachers were used. An MN aggregates and organizes the data collected in the PL environment. Based on the results, we infer that the student and the teacher, under certain conditions, use the physical laboratory as an epistemic tool since the physical interactions prove its use and reuse. In addition, this study allows, in the context of work in the physical laboratory of networks, to identify that the orchestrations of mediation patterns adopted by the teacher influence the students' epistemic practices and the use of the laboratory as a tool to produce new knowledge. The following contributions are presented: (1) The quality of the students' epistemic practices is increased if, in the teacher's dynamics of mediation, the control of the students' action is reduced; (2) The orchestration of the teacher's mediation patterns is essential to achieve beneficial results in student learning with the use of artifacts from the physical laboratory of Computer Networks; (3) For the physical laboratory to become an epistemic tool, it is necessary that the mediation standards allow students to develop epistemic practices to a high or very high degree and there is a certain mediation orchestration.
2024
Autores
Vieira, PM; Rodrigues, F;
Publicação
KNOWLEDGE AND INFORMATION SYSTEMS
Abstract
Imbalanced data are present in various business sectors and must be handled with the proper resampling methods and classification algorithms. To handle imbalanced data, there are numerous resampling and learning method combinations; nonetheless, their effective use necessitates specialised knowledge. In this paper, several approaches, ranging from more accessible to more advanced in the domain of data resampling techniques, will be considered to handle imbalanced data. The application developed delivers recommendations of the most suitable combinations of techniques for a specific dataset by extracting and comparing dataset meta-feature values recorded in a knowledge base. It facilitates effortless classification and automates part of the machine learning pipeline with comparable or better results than state-of-the-art solutions and with a much smaller execution time.
2024
Autores
Lopes, R; Pinto, SM; Parente, MPL; Moreira, PMGP; Baptista, AJ;
Publicação
JOURNAL OF ENGINEERING DESIGN
Abstract
The transportation industry focuses on reducing vehicle weight for fuel economy and emissions. This emphasis promotes the use of coaches, which raises concerns about passenger safety in frontal collisions. The proposal is to correlate the crashworthiness of coaches with the replacement of fibreglass composite materials by a state-of-the-art polymer (DCPD). Based on the ECE R29 standard, FEM models solved by Pamcrash (R) assess the vehicle's crashworthiness. Cross-referencing these results with the Eco-Design X technique, two models are evaluated in terms of environmental impact. The LeanDfX methodology involves multiple analyses for design domains, including model optimisation, manufacturing processes, and eco-design. On a performance scale of 0% to 100%, different 'X' domains are evaluated. The Eco-Design study allowed the assessing the environmental impacts of the proposed solution compared to the original models, is conducted using Simapro v9.2.0.2 and the ReCiPe 2016 methodology. The novel design proposed modifications to the models resulted in significant structural behaviour improvements for driver's physical integrity. The cross results of Design-for-Crashworthiness and Design-for-Eco-Design using the innovative LeanDfX framework provide a new perspective to be integrated into the automotive industry. The use of DCPD is expected to lead to a more crashworthy and environmentally friendly design, while ensuring passenger safety.
2024
Autores
Pires, PB; Prisco, M; Delgado, C; Santos, JD;
Publicação
JOURNAL OF THEORETICAL AND APPLIED ELECTRONIC COMMERCE RESEARCH
Abstract
This study aimed to identify the constructs related to customer experience that underpin e-commerce, as well as their interconnections, to develop a comprehensive conceptual model based on theories-in-use. A quantitative approach was employed through a survey of 441 respondents. Data analysis was conducted using partial least squares structural equation modeling. The research findings revealed that there are a total of 11 constructs: customer experience, customer satisfaction, customer loyalty, word-of-mouth, trust, perceived risk, security and privacy, web content, perceived price, perceived value, and service quality. Furthermore, twelve relationships were established between these constructs, which led to the development of a holistic conceptual model. The identified constructs and the relationships between them are hierarchized, which has practical implications for businesses. It allows them to concentrate on operational activities and formulate and implement strategies that are valued by consumers and supported by empirical evidence. The originality and value of this research lie in the conception and development of a comprehensive e-commerce model, which includes eleven constructs and twelve relationships. It also highlights the pivotal role of the customer experience.
2024
Autores
Matos, P; Alves, R; Oliveira, P; Gonçalves, J;
Publicação
Lecture Notes in Educational Technology
Abstract
The authors present the Effective Solution Based Learning, which derives from Project-Based Learning but is applied to real problems in order to build effective solutions. Emphasis is placed on the effectiveness on the assumption that encourages greater involvement and commitment on the part of students, ensuring a context that is intended to be more attractive and close to what will be their professional reality. Effectiveness is measured by the functionalities considered essential for solving the problem, but also the viability of the solution to be effectively used after the end of development, without the need for continued student involvement. A brief summary of the methodology is presented in the paper, emphasizing, in particular, the criteria and requirements for choosing project themes. The results of the first year of evaluation are also presented in the paper, pointing to a clear reduction in dropouts and an increase in approved students. Considering that this is achieved with more demand and work, it is arguable that it also resulted in students with more knowledge and skills. The authors also include in this paper the results of a survey done to the students, after the project conclusion, to assess the students’ perspective on this methodology. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
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