2015
Autores
Barros, A; Pinho, LM; Yomsi, PM;
Publicação
JOURNAL OF SYSTEMS ARCHITECTURE
Abstract
Recent embedded processor architectures containing multiple heterogeneous cores and non-coherent caches 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 in turns affects the execution time of tasks carrying transactions. Because of this fact the timing behaviour of the task set may not be predictable, thus it is crucial to limit the execution time overheads resulting from aborts. In this paper we formalise a FIFO-based algorithm to order the sequence of commits of concurrent transactions. Then, we propose and evaluate two non-preemptive and one SRP-based fully-preemptive scheduling strategies, in order to avoid transaction starvation.
2015
Autores
Pedersen, TB; Le Gully, T; Pedersen, PD; Ferreira, LL; Šikšnys, L; Stluka, P; Albano, M; Skou, A; Olsen, P;
Publicação
The Success of European Projects using New Information and Communication Technologies
Abstract
This paper presents a framework for management of flexible energy loads in the context of the Internet of Things and the Smart Grid. The framework takes place in the European project Arrowhead, and aims at taking advantage of the flexibility (in time and power) of energy production and consumption offered by sets of devices, appliances or buildings, to help at solving the issue of fluctuating energy production of renewable energies. The underlying concepts are explained, the actors involved in the framework, their incentives and interactions are detailed, and a technical overview is provided. An implementation of the framework is presented, as well as the expected results of the pilots.
2015
Autores
Albano, Michele; Garibay-Martínez, Ricardo; Lino Ferreira, Luis;
Publicação
INForum - Simpósio de Informática (INFORUM 2015).
Abstract
The Arrowhead project [1] considers to normalize all interactions involving embedded
systems by mediating them through services. The Service Oriented Architecture (SOA)
paradigm is applied to both the interactions that provide the service requested by the
user, and other support actions such as the authentication and registration of the devices,
and the services they provide, the look-up of devices and service provided, and orchestration
of services for creation of more complex services. To this purpose, services are
divided into Core Services, which are present in every environment supporting Arrowhead
applications, and user services that implement the applications. The Core Services
set comprises, at least, Authentication Service, Registration Service and Orchestration
Service.
2015
Autores
Ferreira, LL; Pinho, LM; Albano, M; Teixeira, C;
Publicação
SIGBED Rev.
Abstract
2015
Autores
Garibay Martínez, R; Nelissen, G; Ferreira, LL; Pedreiras, P; Pinho, LM;
Publicação
2015 IEEE WORLD CONFERENCE ON FACTORY COMMUNICATION SYSTEMS (WFCS)
Abstract
This paper presents a holistic timing analysis for fixed-priority fork-join Parallel/Distributed tasks (P/D tasks) over a Flexible Time Triggered - Switched Ethernet (FTT-SE) network. The holistic approach considers both time-triggered and event-triggered tasks/messages.
2015
Autores
Garibay Martinez, R; Nelissen, G; Ferreira, LL; Pinho, LM;
Publicação
JOURNAL OF COMPUTER AND SYSTEM SCIENCES
Abstract
In this paper, we propose the Distributed using Optimal Priority Assignment (DOPA) heuristic that finds a feasible partitioning and priority assignment for distributed applications based on the linear transactional model. DOPA partitions the tasks and messages in the distributed system, and makes use of the Optimal Priority Assignment (OPA) algorithm known as Audsley's algorithm, to find the priorities for that partition. The experimental results show how the use of the OPA algorithm increases in average the number of schedulable tasks and messages in a distributed system when compared to the use of Deadline Monotonic (DM) usually favoured in other works. Afterwards, we extend these results to the assignment of Parallel/Distributed applications and present a second heuristic named Parallel-DOPA (P-DOPA). In that case, we show how the partitioning process can be simplified by using the Distributed Stretch Transformation (DST), a parallel transaction transformation algorithm introduced in [1].
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