2025
Autores
Braga, R; Pereira, J; Coelho, F;
Publicação
40TH ANNUAL ACM SYMPOSIUM ON APPLIED COMPUTING
Abstract
Developers of data-intensive georeplicated applications face a difficult decision when selecting a database system. As captured by the CAP theorem, CP systems such as Spanner provide strong consistency that greatly simplifies application development. AP systems such as AntidoteDB providing Transactional Causal Consistency (TCC), ensure availability in face of network partitions and isolate performance from wide-area round-trip times, but avoid lost-update anomalies only when values can be merged. Ideally, an application should be able to adapt to current data and network conditions by selecting which transactional consistency to use for each transaction. In this paper, we test the hypothesis that a georeplicated database system can be built at its core providing only TCC, hence, being AP, but allow an application to execute some transactions under Snapshot Isolation (SI), hence CP. Our main result is showing that this can be achieved even when all the interaction happens through the TCC database system, without additional communication channels between the participants. A preliminary experimental evaluation with a proof-of-concept implementation using AntidoteDB shows that this approach is feasible.
2025
Autores
Joao, MA; Araújo, RE;
Publicação
2025 9th International Young Engineers Forum on Electrical and Computer Engineering (YEF-ECE)
Abstract
The objective of this paper is to delineate the ongoing doctoral research work that is focused on the development of a digital model intended to emulate the real-Time operation of an electrolyzer that is powered by a DC/DC converter. The digital model of the converter and the proton exchange membrane (PEM) electrolyzer (EL) is presented, and it is based on an electrical equivalent model. A primary contribution of this study is the analysis of the errors resulting from the discretization process. Furthermore, the implementation and development of the digital model requires a comprehensive study of the errors and key affecting factors. Additionally, the formulation of a mechanism to reduce these errors is essential for advancing this topic. Preliminary results obtained using the digital emulator developed demonstrated its capacity to reproduce the voltage and current response applied to the electrolyzer with a reduced error compared to the continuous-Time model. © 2025 Elsevier B.V., All rights reserved.
2025
Autores
Teixeira, S; Cortés, A; Thilakarathne, D; Gori, G; Minici, M; Bhuyan, M; Khairova, N; Adewumi, T; Bhuyan, D; O'Keefe, J; Comito, C; Gama, J; Dignum, V;
Publicação
Proceedings of the AAAI/ACM Conference on AI, Ethics, and Society
Abstract
2025
Autores
Barbosa, LS;
Publicação
SOFTWARE ENGINEERING AND FORMAL METHODS, SEFM 2024
Abstract
Modelling complex information systems often entails the need for dealing with scenarios of inconsistency in which several requirements either reinforce or contradict each other. This lecture summarises recent joint work with Juliana Cunha, Alexandre Madeira and Ana Cruz on a variant of transition systems endowed with positive and negative accessibility relations, and a metric space over the lattice of truth values. Such structures are called paraconsistent transition systems, the qualifier stressing a connection to paraconsistent logic, a logic taking inconsistent information as potentially informative. A coalgebraic perspective on this family of structures is also discussed.
2025
Autores
Teixeira, S; Campos, P;
Publicação
Machine Learning Perspectives of Agent-Based Models
Abstract
2025
Autores
Almeida, JB; Barbosa, M; BARTHE, G; Blatter, L; Duarte, JD; Marinho Alves, GXD; Grégoire, B; Oliveira, T; Quaresma, M; Strub, PY; Tsai, MH; Wang, BY; Yang, BY;
Publicação
Abstract
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