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Publications

Publications by HumanISE

2015

Non-preemptive and SRP-based fully-preemptive scheduling of real-time Software Transactional Memory

Authors
Barros, A; Pinho, LM; Yomsi, PM;

Publication
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

An Energy Flexibility Framework on the Internet of Things

Authors
Pedersen, TB; Le Gully, T; Pedersen, PD; Ferreira, LL; Šikšnys, L; Stluka, P; Albano, M; Skou, A; Olsen, P;

Publication
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

Architecture to Support Quality of Service in Arrowhead Systems

Authors
Albano, Michele; Garibay-Martínez, Ricardo; Lino Ferreira, Luis;

Publication
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

Adaptive offloading for infotainment systems

Authors
Ferreira, LL; Pinho, LM; Albano, M; Teixeira, C;

Publication
SIGBED Rev.

Abstract
Infotainment applications in vehicles are currently supported both by the in-vehicle platform, as well as by user's smart devices, such as smartphones and tablets. More and more the user expects that there is a continuous service of applications inside or outside of the vehicle, provided in any of these devices (a simple but common example is hands-free mobile phone calls provided by the vehicle platform). With the increasing complexity of 'apps', it is necessary to support increasing levels of Quality of Service (QoS), with varying resource requirements. Users may want to start listening to music in the smartphone, or video in the tablet, being this application transparently 'moved' into the vehicle when it is started. This paper presents an adaptable offloading mechanism, following a service-oriented architecture pattern, which takes into account the QoS requirements of the applications being executed when making decisions.

2015

Holistic Analysis for Fork-Join Distributed Tasks supported by the FTT-SE Protocol

Authors
Garibay Martínez, R; Nelissen, G; Ferreira, LL; Pedreiras, P; Pinho, LM;

Publication
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

Task partitioning and priority assignment for distributed hard real-time systems

Authors
Garibay Martinez, R; Nelissen, G; Ferreira, LL; Pinho, LM;

Publication
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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