2025
Autores
Freitas, D; Degrandis, P; Sousa, TB;
Publicação
ACM COMPUTING SURVEYS
Abstract
In geo-replicated distributed systems, data is redundantly stored across nodes at different geographical sites, increasing fault tolerance and ensuring low access latency by placing data closer to the end user. With data being concurrently updated across sites, replicas should converge to a consistent view of the data, which leads toward adopting fine-tuned consistency models, namely causal consistency (CC). On the one hand, CC respects the causality between operations, resulting in intuitive outcomes for end users and programmers. On the other hand, it avoids the latency penalty of stronger consistency models and bypasses their availability constraints in the presence of network partitions. Furthermore, when coupled with read-only transactions (ROTs) capable of extracting a unified view of the data, CC avoids the anomalies of weaker consistency models. ROTs, however, cause additional coordination overhead compared to non-transactional reads. This overhead is particularly unwelcome considering the prevalence of read operations in real-world applications, and hence the impact of ROTs on the overall performance of read-heavy systems. With this in mind, there has been a growing effort to optimize the latency and throughput of causally consistent ROTs and to understand how the design of existing systems impacts their performance. In light of these recent developments, the present work surveys the state-of-the-art of causally consistent distributed systems, summarizing and comparing their core characteristics and tradeoffs and examining how their design decisions impact the performance of ROTs. To this end, it first defines some key concepts and presents two impossibility results concerning the properties of ROT algorithms. It then reviews several causally consistent systems with ROT support by identifying their recurring strategies to ensure causality and summarizing each of their designs and properties, stressing their implications on the performance of ROTs. It also surveys two architectural approaches to CC, which present progress toward a standard implementation for causally consistent systems. Finally, it discusses the open challenges identified in the literature.
2025
Autores
Pinto, P; Ferreira, I; Cerveira, A; Grasel, B; Baptista, J;
Publicação
14th International Conference on Renewable Energy Research and Applications, ICRERA 2025
Abstract
The main objective of this work is to identify the most efficient methodologies for transmitting energy generated onshore to offshore gas extraction platforms. Initially, a case study was carried out to determine the most suitable transmission method, AC or DC, with DC being the most suitable. Subsequently, theoretical research was carried out into the type of cable that should be used in this project, resulting in static and dynamic cables. The authors also propose a mathematical optimization model to determine which type of cable section should be used, minimizing the installation cost, power losses and ensuring that the voltage drop is lower than the regulatory limits. Two scenarios were considered in this optimization, one taking power losses into account and the other not. A more positive result was found with the 1000 mm2 section cable, because even though the initial investment is higher, the financial return is superior. © 2025 IEEE.
2025
Autores
Antonio, V; Bronner, U; Nepstad, R; Oliveira, MA;
Publicação
OCEANS 2025 BREST
Abstract
The application of digital twin technology to the ocean is often referred to as Digital Twins of the Ocean (DTO). One notable initiative funded under Horizon Europe programs - Green Deal is the ILIAD - Digital Twin of the Ocean project. One of the objectives of ILIAD is to establish interoperable, data-intensive, and cost-effective DTO pilots. This paper focuses on one such pilot dedicated to environmental monitoring and water quality assessment associated with the OceanLab infrastructure in the Trondheim Fjord, Norway. This paper outlines the architecture and concept of the pilot while providing detailed insights into its application for various what-if scenarios. The scenario presented in this paper is a case study that analyzes the impact of a hypothetical oil spill at the Trondheim terminal. It focuses on the spread of surface oil over a 30-hour period using various pilot modules. The paper also discusses the potential replication of this study in another geographical location.
2025
Autores
Caetano, E; MPM Oliveira, B; Correia, F; Torres, D; Poínhos, R;
Publicação
Acta Portuguesa de Nutrição
Abstract
2025
Autores
Cerqueira, F; Ferreira, MC; Campos, MJ; Fernandes, CS;
Publicação
COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE
Abstract
Background: The study aims to present and explain the development stages of a mobile app designed to improve health literacy for self-management of oncological diseases. Through the integration of gamification, the app aims to enhance patient engagement and education in an interactive manner. Methods: The methodology of Design Science in Information Systems and Software Engineering was employed, which included stages of needs identification, requirements definition, prototyping, and iterative validation of the developed artifact. A total of 132 participants, consisting of patients and healthcare professionals, were involved in the development of the PocketOnco application. The subsequent implementation of the App, PocketOnco, involved usability testing, System Usability Scale assessment, and the collection of qualitative feedback. Results: The usability testing analysis revealed excellent acceptance of PocketOnco, with the gamified elements such as quizzes and reward systems being particularly appreciated for their ability to consistently engage and motivate users. Conclusion: The various stages in the development of this resource ensure the quality of its purpose. The application proved to be a viable and attractive solution for both patients and healthcare professionals, suggesting a promising path for future digital interventions in the field of oncology.
2025
Autores
Nascimento, R; Ferreira, T; Rocha, CD; Filipe, V; Silva, MF; Veiga, G; Rocha, L;
Publicação
JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS
Abstract
Quality inspection inspection systems are critical for maintaining product integrity. Being a repetitive task, when performed by operators only, it can be slow and error-prone. This paper introduces an automated inspection system for quality assessment in casting aluminum parts resorting to a robotic system. The method comprises two processes: filing detection and hole inspection. For filing detection, five deep learning modes were trained. These models include an object detector and four instance segmentation models: YOLOv8, YOLOv8n-seg, YOLOv8s-seg, YOLOv8m-seg, and Mask R-CNN, respectively. Among these, YOLOv8s-seg exhibited the best overall performance, achieving a recall rate of 98.10%, critical for minimizing false negatives and yielding the best overall results. Alongside, the system inspects holes, utilizing image processing techniques like template-matching and blob detection, achieving a 97.30% accuracy and a 2.67% Percentage of Wrong Classifications. The system improves inspection precision and efficiency while supporting sustainability and ergonomic standards, reducing material waste and reducing operator fatigue.
The access to the final selection minute is only available to applicants.
Please check the confirmation e-mail of your application to obtain the access code.