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Detalhes

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Publicações

2017

Nash equilibrium for Proactive Anti-jamming in IEEE 802.15.4e (Emerging wireless sensor actuator technologies for 14.0)

Autores
Homay, A; de Sousa, M; Almeida, L;

Publicação
2017 IEEE 15TH INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS (INDIN)

Abstract
An emerging trend in industry 4.0 is to use wireless communication infrastructure and mesh networks in applications requiring high reliability and safety. Although not a typical industrial production process, railway vehicular networks are also an industrial application which come with stringent reliability and safety requirements. Current research is focusing on using vehicular networks as an enabling technology to actively control the separation between two consecutive vehicles, enforcing a safe distance which is nevertheless much shorter than currently used to maintain vehicle separation. In this respect, we analyze a hopping strategy for Time-Slotted Channel-Hopping (TSCH), which was introduced in the IEEE 802.15.4e amendment with a view of improving the reliability of IEEE 802.15.4 networks. We define a probability framework to estimate the chance of successful hopping assuming two previously merged vehicles, and we design a zero-sum game and propose a payoff function to always place communicating nodes in a Nash equilibrium by choosing whether to hop or not, and therefore maximizing the communication throughput by mitigating jamming signals.

2015

Multiply and Conquer: A Replication Framework for Building Fault Tolerant Industrial Applications

Autores
de Sousa, M; Chrysoulas, C; Homay, AE;

Publicação
PROCEEDINGS 2015 IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS (INDIN)

Abstract
TIEC 61499 defines an execution model for distributed industrial control applications, i.e. a single application distributed among several devices. In such an environment partial failures are likely to occur. In order to avoid probable system malfunctions and breakdowns due to partial failures, the authors have previously proposed a framework where the concept of replication may be applied to the IEC 61499 execution model. This paper focuses on describing an implementation of this replication framework on the FORTE IEC 61499 execution platform, along with the results of the first tests of the implementation. A set-up for the full validation of the approach is also described.

2015

Ambiguities in IEC 61131-3 ST and IL Expression Semantics

Autores
de Sousa, M;

Publicação
PROCEEDINGS 2015 IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS (INDIN)

Abstract
One of the aspects that affects the reliability of a software application is the programming language used for its development. In industrial automation applications, the most commonly used languages are those defined in the IEC 61131-3 standard. This work contains an analysis of the semantics of ST and IL expressions, and highlights ambiguities in the standard that might lead to seemingly correct code being executed and evaluated differently in distinct IEC 61131-3 execution environments. Examples of code that may be evaluated to different results are given, and an evaluation of several commercially available IEC 61131-3 compilers is made and compared. A static code analyzer was developed capable of identifying legal IEC 61131-3 code that may result in ambiguous behavior, and this analyzer was used to test source code currently in use in real-world control applications.

2015

Exploiting Voting Strategies in Partially Replicated IEC 61499 Applications

Autores
de Sousa, M; Chrysoulas, C; Homay, AE;

Publicação
2015 IEEE WORLD CONFERENCE ON FACTORY COMMUNICATION SYSTEMS (WFCS)

Abstract
In a modern industrial environment control programs are distributed among several devices. This raises new issues and challenges especially in failure modes. Building fault tolerant applications can be the solution in order a failure of one sub-component not to jeopardize the execution of the whole application. The authors have proposed a framework to support replicated IEC 61499 applications. In this paper we augment this framework with the support for different voting strategies, propose an extension of the replication communication protocol, and analyse the resulting fault-tolerance semantics. A limited implementation of the framework is also described.

2014

Towards certifiable adaptive reservations for hypervisor-based virtualization

Autores
Groesbrink, S; Almeida, L; De Sousa, M; Petters, SM;

Publicação
Real-Time Technology and Applications - Proceedings

Abstract
Hypervisor-based virtualization provides a natural way to integrate formerly distinct systems into a single mixed-criticality multicore system by consolidating in separated virtual machines. We propose an adaptive computation bandwidth management for such architectures, which is compatible with a potential certification based on the guarantee of specified bandwidth minimums and the isolation of overruns of virtual machines. This management uses periodic servers and an elastic task model to combine analyzability at design time with adaptability at runtime. Mode changes or early termination of VMs trigger a resource redistribution that reassigns spare capacity. In this paper we focus on the integration of an adaptive reservation policy into a virtualization software stack and the co-design of hypervisor and paravirtualized guest operating system. In a concrete implementation on a PowerPC 405, the bandwidth distribution policy incurred in a memory footprint below 2.7KB and a worst-case execution time for the redistribution function below 4 microseconds for realistic low numbers of VMs. Simulations over synthetically generated sets of VMs with random mode changes showed a gain of 13% of computation bandwidth when compared to an approach with fixed partitions and provided a relative error of allocated bandwidth to desired bandwidth 4 times lower. © 2014 IEEE.

Teses
supervisionadas

2019

Predicting Stack Use in Embedded Software Applications

Autor
Carlos Daniel Alves Garcia

Instituição
UP-FEUP

2019

replicação em sistemas distribuídos utilizando a norma iec 61499

Autor
Adriano Manuel de Almeida Santos

Instituição
UP-FEUP

2019

Conversão entre programas LD e SFC (IEC61131-3)

Autor
Luís Manuel Pinto da Silva

Instituição
UP-FEUP

2019

Designing a Decision Support System to Improve Urban Mobility

Autor
Mónica Ariana Ribeiro Fernandes

Instituição
UP-FEUP

2018

Automotive Software Product Lines

Autor
Carlos Daniel Alves Garcia

Instituição
UP-FEUP