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Publicações

Publicações por António Manuel Barros

2014

Non-preemptive Scheduling of Real-Time Software Transactional Memory

Autores
Barros, A; Pinho, LM;

Publicação
Architecture of Computing Systems - ARCS 2014 - 27th International Conference, Lübeck, Germany, February 25-28, 2014. Proceedings

Abstract
Recent embedded processor architectures containing multiple heterogeneous cores and non-coherent caches, bring renewed attention to the use of Software Transactional Memory (STM) as a building block for developing parallel applications. STM promises to ease concurrent and parallel software development, but relies on the possibility of abort conflicting transactions to maintain data consistency, which affects the execution time of tasks carrying transactions. Thus, execution time overheads resulting from aborts must be limited, otherwise the timing behaviour of the task set will not be predictable. In this paper we formalise a FIFO-based algorithm to order the sequence of commits of concurrent transactions. Furthermore, we propose and evaluate two non-preemptive scheduling strategies, in order to avoid transaction starvation. © 2014 Springer International Publishing Switzerland.

2024

Multiprotocol Middleware Translator for IoT

Autores
Cabral, B; Venancio, R; Costa, P; Fonseca, T; Ferreira, LL; Severino, R; Barros, A;

Publicação
2024 27TH EUROMICRO CONFERENCE ON DIGITAL SYSTEM DESIGN, DSD 2024

Abstract
The increasing number of IoT deployment scenarios and applications fostered the development of a multitude of specially crafted communication solutions, several proprietary, which are erecting barriers to IoT interoperability, impairing their pervasiveness. To address such problems, several middleware solutions exist to standardize IoT communications, hence promoting and facilitating interoperability. Although being increasingly adopted in most IoT systems, it became clear that there was no one size fits all solution that could address the multiple Quality-of-Service heterogeneous IoT systems may impose. Consequently, we witness new interoperability challenges regarding the usage of diverse middleware. In this work, we address this issue by proposing a novel architecture - the PolyglIoT, that can effectively interconnect diverse middleware solutions while considering the delivery QoS requirements alongside the proposed translation. We analyze the performance and robustness of the solution and show that such Multiprotocol Translator is feasible and can achieve a high performance, thus becoming a fundamental piece to enable future highly heterogeneous IoT systems of systems.

2020

Non-functional requirements in the ELASTIC architecture

Autores
Nogueira, L; Barros, A; Zubia, C; Faura, D; Gracia Pérez, D; Miguel Pinho, L;

Publicação
ACM SIGAda Ada Letters

Abstract
The new generation of smart systems require processing a vast amount of information from distributed data sources, while fulfilling non-functional properties related to real-time, energy-efficiency, communication quality and security. The ELASTIC software architecture is being developed to tackle this challenge, considering the complete continuum from the edge to the cloud. This paper provides a brief analysis of the smart application considered in the project, and the requirements emanating from their non-functional properties. The paper then identifies some of the technical constrains imposed to the ELASTIC software architecture to allow guaranteeing the non-functional requirements of the systems.

2022

Managing Non-functional Requirements in an ELASTIC Edge-Cloud Continuum

Autores
Sousa, R; Pinho, LM; Barros, A; Gonzalez Hierro, M; Zubia, C; Sabate, E; Kartsakli, E;

Publicação
Ada User Journal

Abstract
The ELASTIC European project addresses the emergence of extreme-scale analytics, providing a software architecture with a new elasticity concept, intended to support smart cyber-physical systems with performance requirements from extreme-scale analytics workloads. One of the main challenges being tackled by ELASTIC is the necessity to simultaneously fulfil the non-functional properties inherited from smart systems, such as real-time, energy efficiency, communication quality or security. This paper presents how the ELASTIC architecture monitors and manages such non-functional requirements, working in close collaboration with the component responsible for the orchestration of elasticity. © 2022, Ada-Europe. All rights reserved.

2022

A Model Annotation Approach for the Support of Software Energy Properties Management using AMALTHEA

Autores
Gomes, R; Carvalho, T; Barros, A; Pinho, LM;

Publicação
5th IEEE International Conference on Industrial Cyber-Physical Systems, ICPS 2022, Coventry, United Kingdom, May 24-26, 2022

Abstract
The automotive software industry is gradually introducing new functionalities and technologies that increase the efficiency, safety, and comfort of vehicles. These functionalities are quickly accepted by consumers; however, the consequences of this evolution are twofold. First, developing correct systems that integrate more applications and hardware is becoming more complex. To cope with this, new standards (such as Adaptive AUTOSAR) and frameworks (such as AMALTHEA) are being proposed, to assist the development of flexible systems based on high-performance electronic control units (ECU). Second, the increase of functionality is supported by a dramatic increase of electronic parts on automotive systems. Consequently, the impact of software on the electrical power and energy non-functional requirements of automotive systems has come under focus. In this paper we propose an automatic and self-contained approach that supplements a model of an automotive system described on the AMALTHEA platform with energy-related annotations. From the analysis of simulation (or execution) traces of the modelled software, we estimate the power consumption for each software component, on a target hardware platform. This method enables energy analysis during the entire development life-cycle; furthermore, it contributes for the development of energy management strategies for dynamic and self-adaptive systems. © 2022 IEEE.

2013

Revisiting transactions in Ada

Autores
Barros, A; Pinho, LM;

Publicação
ACM SIGAda Ada Letters

Abstract
Classical lock-based concurrency control does not scale with current and foreseen multi-core architectures, opening space for alternative concurrency control mechanisms. The concept of transactions executing concurrently in isolation with an underlying mechanism maintaining a consistent system state was already explored in fault-tolerant and distributed systems, and is currently being explored by transactional memory, this time being used to manage concurrent memory access. In this paper we discuss the use of Software Transactional Memory (STM), and how Ada can provide support for it. Furthermore, we draft a general programming interface to transactional memory, supporting future implementations of STM oriented to real-time systems.

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