2024
Autores
Ribeiro, JEF; Silva, JG; Aguiar, A;
Publicação
IEEE ACCESS
Abstract
Domain-specific standards and documents heavily regulate safety-critical systems. One example is the DO-178C standard for aerospace, which guides organizations to achieve system safety and evidence for their certification. Under such regulated contexts, most organizations use traditional development processes, in contrast to the massive adoption of Agile in the software industry. Among other benefits, Agile methods promise faster delivery and better flexibility to address customer needs. Adopting Agile methods and practices are possible in aerospace because the DO-178C standard does not prescribe concrete software development methods. In spite of that, Agile development is not used in DO-178C contexts. To help change that, our research aims to understand whether and how organizations engineering safety-critical software systems for aerospace may benefit from Agile methods and practices. We analyzed the DO-178C standard and confirm that it is compatible with Agile methods. Then, we present a systematic literature mapping of adopting Agile in software development for aerospace, where we identified significant concerns, recurrent issues, and several challenges. Some real industry aerospace projects provided us with important data and the perspective of domain experts about the pros and cons of Agile methods in this context. We conclude by proposing an agenda of research opportunities to improve safety-critical software development towards agility that we consider worthy of further research, application and confirmation in wider contexts.
2024
Autores
Viera, M; Pardo, A; Saraiva, J;
Publicação
FUNCTIONAL AND LOGIC PROGRAMMING, FLOPS 2024
Abstract
Tabulation is a well-known technique for improving the efficiency of recursive functions with redundant function calls. A key point in the application of this technique is to identify a suitable representation for the table. In this paper, we propose the use of zippers as tables in the tabulation process. Our approach relies on a generic function zipWithZipper, that makes strong use of lazy evaluation to traverse two zippers in a circular manner. The technique turns out to be particularly efficient when the arguments to recursive calls are closely situated within the function domain. For example, in the case of natural numbers this means function calls on fairly contiguous values. Likewise, when dealing with tree structures, it means functions calls on immediate sub-trees and parent nodes. This results in a concise and efficient zipper-based embedding of attribute grammars.
2024
Autores
Gonçalves, ASR; Alves, C; Graça, SR; Pires, A;
Publicação
CLINICAL ORAL INVESTIGATIONS
Abstract
Objectives Space, an extreme environment, poses significant challenges to human physiology, including adverse effects on oral health (e.g., increase of periodontitis prevalence, caries, tooth sensitivity). This study investigates the differences in oral health routines and oral manifestations among analog astronauts during their daily routines and simulated space missions conducted on Earth. Materials and methods This research focused on scientist-astronaut candidates of the International Institute for Astronautical Sciences (IIAS) and analog astronauts from other institutions. The study used a cross-sectional methodology with a descriptive component. A total of 16 participants, comprising individuals aged between 21 and 55 years, were invited to complete an online questionnaire. A comparison was made between the subjects' oral hygiene practices in everyday life (designated as Earth in this research) and their oral hygiene routines during their space analog missions. Results (i) Toothbrushing duration was mostly 1-3 minutes (n = 13; 81.30% on Earth; n = 11; 68.80% on a mission); (ii) time spent was the greatest difficulty in maintaining oral hygiene routine on a mission (n = 9; 53,6%); (iii) There were more experienced oral symptoms on Earth (n = 12; 75%) than on mission (n = 7; 43.80%); (iv) The most frequent frequency of oral check-ups was > 12 months (n = 6; 37,5%); (v) Oral health materials were scarce on the mission (n = 9; 56.30%); (vi) For the majority, personal oral hygiene was classified as good (n = 9; 56.30% on Earth; n = 7; 43.80% on the mission). Conclusion and Clinical relevance This research contributes to increasing knowledge of oral hygiene measures in extreme environments, but further research is needed as this topic remains relatively understudied. This study represents an initial contribution to oral health in analog space missions, aiming to propose guidelines for future missions, including deep space missions and expeditions to extreme environments.
2024
Autores
Soares, L; Perez-Herrera, RA; Novais, S; Ferreira, A; Silva, S; Frazao, O;
Publicação
PHOTONICS
Abstract
In this study, different configurations based on linear fiber lasers were proposed and experimentally demonstrated to measure the concentration of liquid solutions. Samples of paracetamol liquid solutions with different concentrations, in the range from 52.61 to 201.33 g/kg, were used as a case-study. The optical gain was provided by a commercial bidirectional Erbium-Doped Fiber Amplifier (EDFA) and the linear cavity was obtained using two commercial Fiber Bragg Gratings (FBGs). The main difference of each configuration was the coupling ratio of the optical coupler used to extract the system signal. The sensing head corresponded to a Single-Mode Fiber (SMF) tip that worked as an intensity sensor. The results reveal that, despite the optical coupler used (50:50, 60:40, 70:30 or 80:20), all the configurations reached the laser condition, however, the concentration sensing was only possible using a laser drive current near to the threshold value. The configurations using a 70:30 and an 80:20 optical coupler allowed paracetamol concentration measurements with a higher sensitivity of (-3.00 +/- 0.24) pW/(g/kg) to be performed. In terms of resolution, the highest value obtained was 1.75 g/kg, when it was extracted at 20% of the output power to the linear cavity fiber laser configuration.
2024
Autores
Faria, JP; Verbeek, F; Fasolino, AR;
Publicação
ACM SIGSOFT Softw. Eng. Notes
Abstract
2024
Autores
Serôdio, C; Mestre, P; Cabral, J; Gomes, M; Branco, F;
Publicação
APPLIED SCIENCES-BASEL
Abstract
In the context of Industry 4.0, this paper explores the vital role of advanced technologies, including Cyber-Physical Systems (CPS), Big Data, Internet of Things (IoT), digital twins, and Artificial Intelligence (AI), in enhancing data valorization and management within industries. These technologies are integral to addressing the challenges of producing highly customized products in mass, necessitating the complete digitization and integration of information technology (IT) and operational technology (OT) for flexible and automated manufacturing processes. The paper emphasizes the importance of interoperability through Service-Oriented Architectures (SOA), Manufacturing-as-a-Service (MaaS), and Resource-as-a-Service (RaaS) to achieve seamless integration across systems, which is critical for the Industry 4.0 vision of a fully interconnected, autonomous industry. Furthermore, it discusses the evolution towards Supply Chain 4.0, highlighting the need for Transportation Management Systems (TMS) enhanced by GPS and real-time data for efficient logistics. A guideline for implementing CPS within Industry 4.0 environments is provided, focusing on a case study of real-time data acquisition from logistics vehicles using CPS devices. The study proposes a CPS architecture and a generic platform for asset tracking to address integration challenges efficiently and facilitate the easy incorporation of new components and applications. Preliminary tests indicate the platform's real-time performance is satisfactory, with negligible delay under test conditions, showcasing its potential for logistics applications and beyond.
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