2011.bib
@inproceedings{MARQUES_INFORUM_2011,
author = {Marques, L. and Vasconcelos, V. and Pedreiras, P. and Almeida, L.},
title = {Towards Efficient Transient Fault Handling in Time-Triggered Systems},
booktitle = {INFORUM - Simp\'{o}sio de Inform\'{a}tica},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {},
address = {Coimbra, Portugal},
month = {September},
organization = {},
publisher = {},
doi = {},
issn = {},
isbn = {},
keywords = {CAN, FTT-CAN, Scheduling, Real-Time communications},
note = {},
key = {},
abstract = {Transient communication faults in distributed control systems (DCS) are unavoidable but must be handled adequately in order to enforce correct system behaviour. A typical way of handling transient faults is temporal redundancy by means of retransmissions. However, DCS are frequently designed with time-triggered architectures, being scheduled offline and not coping efficiently with retransmissions as these require the pre-allocation of bandwidth that, in the absence of errors, is wasted. In this paper we propose using the Flexible Time-Triggered paradigm to reconcile the Time-Triggered model with on-line scheduling of retransmissions when needed, only, leading to an efficient bandwidth usage. This is confirmed with preliminary experimental results obtained on an FTT-CAN network}
}
@inproceedings{SANTOS_EMSOFT_2011,
author = {Santos, R. and Behnam, M. and Nolte, T. and Pedreiras, P. and Almeida, L.},
title = {Multi-level hierarchical scheduling in Ethernet switches},
booktitle = {11th International Conference on Embedded Software (EMSOFT'2011) Proceedings},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {185--194},
address = {Taipei, Taiwan},
month = {October},
organization = {},
publisher = {},
doi = {},
issn = {},
isbn = {978-1-4503-0714-7},
keywords = {Embedded Systems, NES, Ethernet, Switch, Analytical models, Bandwidth, Protocols, Real time systems, Servers, Time factors},
note = {},
key = {},
abstract = {The complexity of Networked Embedded Systems (NES) has been growing steeply, due to increases both in size and functionality, and is becoming a major development concern. This situation is pushing for paradigm changes in NES design methodologies towards higher composability and flexibility. Component-oriented design technologies, in particular supported by server-based scheduling, seem to be good candidates to provide the needed properties. As a response we developed a multi-level hierarchical server-based architecture for Ethernet switches that provides composability and supports online adaptation and reconfiguration. This paper extends our work, presenting the associated response-time based schedulability analysis, necessary for the admission control procedure. Additionally, we have derived the temporal complexity of the analysis, which is shown to be O(n2), where n is the number of higher priority components associated with a given server. Finally, we present a proof-of-concept implementation and a set of experimental results that validates the analysis}
}
@inproceedings{SANTOS_APRES_2011,
author = {Santos, R. and Pedreiras, P. and Behnam, M. and Nolte, T. and Almeida, L.},
title = {Demonstrating an Ethernet Switch Enhanced with Hierarchical Scheduling},
booktitle = {3rd Workshop on Adaptive and Reconfigurable Embedded Systems (APRES'2011) Proceedings},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {},
address = {Chicago, USA},
month = {April},
organization = {},
publisher = {},
doi = {},
issn = {},
isbn = {},
keywords = {Embedded systems, NES, Ethernet, Switch, FTT, Real-Time communications, Servers, Scheduling, Quality of Service},
note = {},
key = {},
abstract = {The complexity of Networked Embedded Systems (NES) has been growing steeply, due to increases both in size and functionality, and is becoming a major development concern. This situation is pushing for paradigm changes in NES design methodologies towards higher composability and flexibility. Component-oriented design technologies, in particular supported by server-based scheduling, seem to be good candidates to provide the needed properties. As response, we developed a multi-level hierarchical server-based architecture for Ethernet switches that provides composability and supports online adaptation and reconfiguration [1] [2]. This framework exhibits the following features: 1) A hierarchical architecture that supports server composition, virtual real-time channels providing temporal isolation (composability in the time domain); 2) Analytical tools for guaranteed real-time behavior; 3) Simple interface to adapt and reconfigure servers during runtime}
}
@inproceedings{SANTOS_RTSSATWORK_2011,
author = {Santos, R. and Pedreiras, P. and Behnam, M. and Nolte, T. and Almeida, L.},
title = {Demonstrating an Ethernet switch enhanced with hierarchical scheduling},
booktitle = {32nd IEEE Real-Time Systems Symposium (RTSS'2011) Open Demo Session of Real-Time Techniques and Technologies},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {},
address = {Vienna, Austria},
month = {November},
organization = {},
publisher = {},
doi = {},
issn = {},
isbn = {},
keywords = {Embedded systems, NES, Ethernet, Switch, FTT, Real-Time communications, Servers, Scheduling, Quality of Service},
note = {},
key = {},
abstract = {The complexity of Networked Embedded Systems (NES) has been growing steeply, due to increases both in size and functionality, and is becoming a major development concern. This situation is pushing for paradigm changes in NES design methodologies towards higher composability and flexibility. Component-oriented design technologies, in particular supported by server-based scheduling, seem to be good candidates to provide the needed properties. As response, we developed a multi-level hierarchical server-based architecture for Ethernet switches that provides composability and supports online adaptation and reconfiguration [1] [2]. This framework exhibits the following features: 1) A hierarchical architecture that supports server composition, virtual real-time channels providing temporal isolation (composability in the time domain); 2) Analytical tools for guaranteed real-time behavior; 3) Simple interface to adapt and reconfigure servers during runtime}
}
@inproceedings{SILVA_REC_2011,
author = {Silva, L. and Oliveira, A. and Pedreiras, P. and Santos, R.},
title = {Liga\c{c}\~{a}o de Alto Desempenho entre FPGAs para Switch Ethernet FTT},
booktitle = {VII Jornadas sobre Sistemas Reconfigur\'{a}veis (REC'2011) Proceedings},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {},
address = {Oporto, Portugal},
month = {February},
organization = {},
publisher = {},
doi = {},
issn = {},
isbn = {},
keywords = {FTT, Ethernet, Switch, FPGA, Real-Time communications, HaRTES},
note = {},
key = {},
abstract = {A Ethernet como de?nida na norma IEEE 802.3 n\~{a}o \'{e} adequada a aplica\c{c}\~{o}es tempo-real. Apesar de terem surgido v\'{a}rios protocolos que tornam poss\'{i}vel a sua aplica\c{c}\~{a}o em sistemas de tempo-real, as garantias oferecidas s\~{a}o em geral est\'{a}ticas e pouco ?ex\'{i}veis. O projecto HaRTES tem como objectivo o desenvolvimento de um switch Fast Ethernet com recurso a tecnologia FPGA, capaz de fornecer servic?os de comunica\c{c}\~{a}o tempo-real com garantias din\^{a}micas de qualidade de servi\c{c}o. No entanto, os recursos oferecidos pelas FPGAs e placas de desenvolvimento actuais sao limitados para este tipo de projecto, di?cultando a escalabilidade do switch em diversos aspectos (e.g. numero de portos). O presente artigo discute o desenvolvimento de uma liga\c{c}\~{a}o s\'{e}rie multi-gigabit entre FPGAs que constituem o switch, com vista a minorar as limita\c{c}\~{o}es de escalabilidade no projecto do switch HaRTES}
}
@article{SANTOS_SIGBED_2011,
author = {Santos, R. and Pedreiras, P. and Behnam, M. and Nolte, T. and Almeida, L.},
title = {Hierarchical server-based traffic scheduling in ethernet switches},
journal = {ACM SIGBED Review},
year = {2011},
volume = {8},
number = {1},
pages = {68--69},
month = {March},
doi = {},
issn = {},
isbn = {},
keywords = {Ethernet, Real-Time communications, Switch, Servers, Quality of Service},
note = {},
key = {},
abstract = {Distributed Embedded Real-Time Systems (DERTS) are ever more complex, consisting of an increasing number of nodes with more functionality and handling more data. This scenario is pushing for paradigm changes in the methodologies to design complex DERTS. Namely, component-oriented design methodologies, exhibiting the composability property are considered an effective means to tackle the growing complexity of DERTS. Server-oriented architectures have proven to be an effective means to enable controlled resource sharing, providing composability among application components as well as between the application software and the hardware platform on which they execute}
}
@article{SILVESTRE_IE_2011,
author = {Silvestre, J. and Almeida, L. and Marau, R. and Pedreiras, P.},
title = {On-line QoS Management for Multimedia Real-Time Transmission in Industrial Networks},
journal = {IEEE Transactions on Industrial Electronics},
year = {2011},
volume = {58},
number = {3},
pages = {1061--1071},
month = {March},
doi = {10.1109/TIE.2010.2049711},
issn = {0278-0046},
isbn = {ISBN-OPTIONAL},
keywords = {Ethernet, Real-Time communications, Industrial Networks, quality of service},
note = {},
key = {},
abstract = {A growing number of industrial applications incorporate multimedia information processing. These multimedia applications are commonly distributed and subject to time constraints that must be met across networks without creating intolerable interference over typical control flows. However, multimedia traffic, in general, and video streaming, in particular, have specific characteristics that conflict with the operational framework of conventional real-time protocols. In particular, video compressors generate highly variable bit-rate streams that mismatch the constant-bit-rate channels typically provided by real-time protocols, severely reducing the efficiency of network utilization. This paper focuses on low-latency multimedia transmission over Ethernet with dynamic quality-of-service (QoS) management. We propose a multidimensional mechanism that controls, in an integrated way, both the compression parameters and the network bandwidth allocated to each stream. The goal is to provide the best possible QoS to each stream, recomputing the compression levels and network bandwidth whenever significant events, such as channel setup/teardown, or structural changes happen. This paper also presents novel QoS metrics based both on the image quality and network parameters. Several experiments with prerecorded video streams illustrate the advantages of the proposed approach and the convenience of the metrics}
}
@inproceedings{BEHNAM_ETFA_2011,
author = {Behnam, M. and Marau, R. and Pedreiras, P.},
title = {Analysis and optimization of the MTU in real-time communications over Switched Ethernet},
booktitle = {16th Conference on Emerging Technologies Factory Automation (ETFA'2011) Proceedings},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {1--7},
address = {Toulouse, France},
month = {September},
organization = {},
publisher = {},
doi = {10.1109/ETFA.2011.6059021},
issn = {1946-0740},
isbn = {978-1-4577-0016-3},
keywords = {Ethernet, FTT, FTT-SE, protocols, Real-Time communications, Scheduling, MTU},
note = {},
key = {},
abstract = {The Flexible Time-Triggered communication over Switched Ethernet protocol (FTT-SE) was proposed to overcome the limitation of guaranteeing the real-time communication requirements of conventional switches, and at the same time to support reconfiguration of dynamic adaptive systems. The protocol fragments large messages into a sequence of packets that are individually scheduled. The maximum transmission unit (MTU), that restricts the packets size, has a significant effect on the schedulability of the packets. In this paper, we investigate the problem of selecting the optimal MTU size that maximizes the schedulability of real-time messages. We propose two algorithms to find optimal/sub-optimal values of MTU; the first one finds an optimal solution but exhibits high computational complexity, while the second one is sub-optimal but exhibits a lower computational complexity. Finally, we evaluate our proposed algorithms by means of simulation studies and compare their results with the results of assigning MTU to the maximum packet size that the protocol can allow}
}
@inproceedings{SILVA_RTSSATWORK_2011,
author = {Silva, L. and Marau, R. and Almeida, L.},
title = {Demonstrating Real-Time Reconfiguration in Service-Oriented Distributed Systems},
booktitle = {32nd IEEE Real-Time Systems Symposium (RTSS'2011) at Work Session},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {},
address = {Vienna, Austria},
month = {November},
organization = {},
publisher = {},
doi = {},
issn = {},
isbn = {},
keywords = {Real-Time communications, Distributed systems, iLAND, Service-oriented system},
note = {},
key = {},
abstract = {}
}
@inproceedings{BEHNAM_WCTT_2011,
author = {Behnam, M. and Iqbal, Z. and Silva, P. and Marau, R. and Almeida, L. and Portugal, P.},
title = {Engineering and Analyzing Multi-Switch Networks with Single Point of Control},
booktitle = {1st International Workshop on Worst-case Traversal Time (WCTT'2011) Proceedings},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {},
address = {Vienna, Austria},
month = {November},
organization = {},
publisher = {},
doi = {},
issn = {},
isbn = {},
keywords = {Real-Time communications, FTT, FTT-SE, Ethernet, Embedded systems},
note = {},
key = {},
abstract = {Recent trends in distributed embedded systems have shown an increase in the amount and heterogeneity of the information that needs to be exchanged, together with a growing importance of supporting dynamic reconfiguration and adaptive behaviors. In this paper we focus on Ethernet technology and we address the case of middle-size networking infrastructure with a few switches. We use the FTT-SE protocol to support dynamic heterogeneous real-time transactions with temporal isolation and we propose the needed scheduling adaptations to support multi-hop network configurations. The paper also includes a companion worst-case response-time analysis that allows verifying the timeliness of the system}
}
@inproceedings{YEKEH_SIES_2011,
author = {Yekeh, F. and Pordel, M. and Almeida, L. and Behnam, M. and Portugal, P.},
title = {Exploring alternatives to scale FTT-SE to large networks},
booktitle = {6th IEEE International Symposium on Industrial Embedded Systems (SIES'2011) Proceedings},
year = {2011},
editor = {},
volume = {},
series = {},
pages = {},
address = {Vasteras, Sweden},
month = {June},
organization = {},
publisher = {},
doi = {10.1109/SIES.2011.5953692},
issn = {},
isbn = {978-1-61284-819-8},
keywords = {Real-Time communications, FTT, FTT-SE, Ethernet, Embedded systems},
note = {},
key = {},
abstract = {Nowadays, most complex embedded systems follow a distributed approach in which a network interconnects potentially large numbers of nodes. One technology that is being increasingly used is switched Ethernet, but real-time variants of this protocol typically limit scalability. In this paper, we focus on the scalability of the Flexible Time Triggered communication over Switched Ethernet (FTT-SE), which has been proposed to support hard real-time applications in a flexible and predictable manner. Moreover, time-triggered and event-triggered communication methods are supported in this protocol. FTT-SE has already been explored and investigated for small scale networked applications. In this paper we address the protocol scalability and suggest three different solutions with a qualitative assessment}
}