The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Christian Fraboul - One of the best experts on this subject based on the ideXlab platform.

  • worst case backlog evaluation of avionics switched ethernet networks with the Trajectory Approach
    Euromicro Conference on Real-Time Systems, 2012
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Worst case backlog evaluation is a key issue to avoid under or over sizing of output port buffers for store-and-forward switches. Typically, the dimensioning of switches in the context of avionics is at least as important as the upper bounding of the end-to-end delays. This paper presents a new method based on the Trajectory Approach for backlog evaluation of output ports of AFDX switches. On an industrial AFDX configuration, this new method leads to an average buffer size reduction of 10\% compared to the existing Network Calculus Approach.

  • ECRTS - Worst-Case Backlog Evaluation of Avionics Switched Ethernet Networks with the Trajectory Approach
    2012 24th Euromicro Conference on Real-Time Systems, 2012
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Worst case backlog evaluation is a key issue to avoid under or over sizing of output port buffers for store-and-forward switches. Typically, the dimensioning of switches in the context of avionics is at least as important as the upper bounding of the end-to-end delays. This paper presents a new method based on the Trajectory Approach for backlog evaluation of output ports of AFDX switches. On an industrial AFDX configuration, this new method leads to an average buffer size reduction of 10\% compared to the existing Network Calculus Approach.

  • Applying Trajectory Approach with static priority queuing for improving the use of available AFDX resources
    2010
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (Avionics Full Duplex Switched Ethernet) standardized as ARINC 664 is a major upgrade for avionics systems. The mandatory certification implies a worst-case delay analysis of all the flows transmitted on the AFDX network. Up to now, this analysis is done thanks to a tool based on a Network Calculus Approach. The more recent Trajectory Approach has been proposed for the computation of worst-case response time in distributed systems. This paper shows how the worst-case delay analysis of an AFDX network can be improved using an optimized Trajectory Approach. This Approach, which implements static priority QoS policies, provides bound needed for deterministic avionics flows (high priority) and allows addition of (lower priority) non avionics flows.

  • Improving the worst-case delay analysis of an AFDX network using an optimized Trajectory Approach
    IEEE Transactions on Industrial Informatics, 2010
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Avionics Full Duplex Switched Ethernet (AFDX) standardized as ARINC 664 is a major upgrade for avionics systems. The mandatory certification implies a worst-case delay analysis of all the flows transmitted on the AFDX network. Up to now, this analysis is done thanks to a tool based on a Network Calculus Approach. The more recent Trajectory Approach has been proposed for the computation of worst-case response time in distributed systems. This paper shows how the worst-case delay analysis of the AFDX can be improved using an optimized Trajectory Approach. The Network Calculus and the Trajectory Approaches are compared on a real avionics AFDX configuration. Moreover, an evaluation of an upper bound of the pessimism of each Approach is proposed.

  • Applying and optimizing Trajectory Approach for performance evaluation of AFDX avionics network
    ETFA 2009 - 2009 IEEE Conference on Emerging Technologies and Factory Automation, 2009
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (avionics full duplex switched Ethernet) standardized as ARINC 664 is a major upgrade for avionics systems. But network delay analysis is required to evaluate end-to-end delay's upper bounds. The network calculus Approach, that has been used to evaluate such end-to-end delay upper bounds for certification purposes, is shortly described. In this paper we present how the Trajectory Approach can be applied to an AFDX avionics network. Moreover we explain how this Approach can be optimized in this context. We show that, on an industrial configuration, it outperforms existing end-to-end delays upper bounds.

Henri Bauer - One of the best experts on this subject based on the ideXlab platform.

  • ETFA - Optimistic problems in the Trajectory Approach in FIFO context
    2013 IEEE 18th Conference on Emerging Technologies & Factory Automation (ETFA), 2013
    Co-Authors: Georges Kemayo, Henri Bauer, Frédéric Ridouard, Pascal Richard
    Abstract:

    AFDX (Avionics Full Duplex Switched Ethernet) is a network designed for safety-critical applications in avionics systems. The flow analysis is mandatory for the certification. The end-to-end (ETE) delay upper bound has to be computed and hence guaranteed. Different Approaches have been proposed to compute ETE delay upper bound such as the Network Calculus and the Trajectory method. Both methods are deemed to introduce some pessimism in the computations. We only focus next on the Trajectory Approach. This paper shows that the original Trajectory Approach is flawed and can compute an optimistic ETE. We present a counter-example and discuss the sources of optimism that must be considered to revise the Trajectory method.

  • worst case backlog evaluation of avionics switched ethernet networks with the Trajectory Approach
    Euromicro Conference on Real-Time Systems, 2012
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Worst case backlog evaluation is a key issue to avoid under or over sizing of output port buffers for store-and-forward switches. Typically, the dimensioning of switches in the context of avionics is at least as important as the upper bounding of the end-to-end delays. This paper presents a new method based on the Trajectory Approach for backlog evaluation of output ports of AFDX switches. On an industrial AFDX configuration, this new method leads to an average buffer size reduction of 10\% compared to the existing Network Calculus Approach.

  • ECRTS - Worst-Case Backlog Evaluation of Avionics Switched Ethernet Networks with the Trajectory Approach
    2012 24th Euromicro Conference on Real-Time Systems, 2012
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Worst case backlog evaluation is a key issue to avoid under or over sizing of output port buffers for store-and-forward switches. Typically, the dimensioning of switches in the context of avionics is at least as important as the upper bounding of the end-to-end delays. This paper presents a new method based on the Trajectory Approach for backlog evaluation of output ports of AFDX switches. On an industrial AFDX configuration, this new method leads to an average buffer size reduction of 10\% compared to the existing Network Calculus Approach.

  • Applying Trajectory Approach with static priority queuing for improving the use of available AFDX resources
    2010
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (Avionics Full Duplex Switched Ethernet) standardized as ARINC 664 is a major upgrade for avionics systems. The mandatory certification implies a worst-case delay analysis of all the flows transmitted on the AFDX network. Up to now, this analysis is done thanks to a tool based on a Network Calculus Approach. The more recent Trajectory Approach has been proposed for the computation of worst-case response time in distributed systems. This paper shows how the worst-case delay analysis of an AFDX network can be improved using an optimized Trajectory Approach. This Approach, which implements static priority QoS policies, provides bound needed for deterministic avionics flows (high priority) and allows addition of (lower priority) non avionics flows.

  • Improving the worst-case delay analysis of an AFDX network using an optimized Trajectory Approach
    IEEE Transactions on Industrial Informatics, 2010
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Avionics Full Duplex Switched Ethernet (AFDX) standardized as ARINC 664 is a major upgrade for avionics systems. The mandatory certification implies a worst-case delay analysis of all the flows transmitted on the AFDX network. Up to now, this analysis is done thanks to a tool based on a Network Calculus Approach. The more recent Trajectory Approach has been proposed for the computation of worst-case response time in distributed systems. This paper shows how the worst-case delay analysis of the AFDX can be improved using an optimized Trajectory Approach. The Network Calculus and the Trajectory Approaches are compared on a real avionics AFDX configuration. Moreover, an evaluation of an upper bound of the pessimism of each Approach is proposed.

Laurent George - One of the best experts on this subject based on the ideXlab platform.

  • Deterministic delay analysis of AVB switched Ethernet networks using an extended Trajectory Approach
    Real-Time Systems, 2017
    Co-Authors: Xiaoting Li, Laurent George
    Abstract:

    Audio Video Bridging (AVB) switched Ethernet is being considered as a promising network alternative solution for the automotive industry thanks to its high data transmission rate and dedicated bandwidth for real-time traffic. However, guaranteeing deterministic communications of an AVB switched Ethernet network remains a key issue for safety-critical applications in automotive domain. In order to ensure real-time timeliness constraints for any flow sent in AVB switched Ethernet networks, we establish new bounds on the worst-case end-to-end delay of any flow. Our contributions are the following: (i) We first develop a worst-case delay analysis in the context of AVB switched Ethernet network based on an extension of the Trajectory Approach. (ii) Then we take into account serialization constraints on frame transmissions to improve the computation of worst-case end-to-end delay bounds. (iii) Finally, we refine the proposed Approach by taking into consideration the AVB traffic shaping characteristics. The performance of the proposed Approach is illustrated on a set of representative automotive examples.

  • Deterministic scheduling in Networks-on-Chip using the Trajectory Approach
    2015
    Co-Authors: Ermis Papastefanakis, Laurent George
    Abstract:

    —In this paper, we consider the problem of guaranteeing real-time end-to-end transmission time for flows sent on a Network-on-Chip (NoC) with First-in First-out (FIFO) scheduling on each node. We show how to adapt the Trajectory Approach, used in the context of Avionics Full DupleX switched Ethernet (AFDX) networks to characterize end-to-end transmission delays, to the context of NoC-based Systems-on-Chip (SoCs). We characterize the benefit of the Trajectory Approach on an example.

  • ISORC - Deterministic Scheduling in Network-on-Chip Using the Trajectory Approach
    2015 IEEE 18th International Symposium on Real-Time Distributed Computing, 2015
    Co-Authors: Ermis Papastefanakis, Laurent George
    Abstract:

    In this paper, we consider the problem of guaranteeing real-time end-to-end transmission time for flows sent on a Network-on-Chip (NoC) with First-in First-out (FIFO) scheduling on each node. We show how to adapt the Trajectory Approach, used in the context of Avionics Full DupleX switched Ethernet (AFDX) networks to characterize end-to-end transmission delays, to the context of NoC-based Systems-on-Chip (SoCs). We characterize the benefit of the Trajectory Approach on an example.

  • The Trajectory Approach for AFDX FIFO networks revisited and corrected
    2014
    Co-Authors: Olivier Cros, Laurent George
    Abstract:

    We consider the problem of dimensioning realtime AFDX FIFO networks with a worst-case end-to-end delay analysis. The state-of-the-art has considered several Approaches to compute these worst-case end-to-end delays. Among them, the Trajectory Approach has received more attention as it has been shown to provide tight end-to-end delay upper bounds. Recently, it has been proved that current Trajectory analysis can be optimistic for some corner cases, leading in its current form, to certification issues. In this paper, we first characterize the source of optimism in the Trajectory Approach on detailed examples. Then, we provide a correction to the identified problems. Two problems are solved: the first one is on the definition of the time interval to consider for the worst-case end-to-end response time computation of flows at their source nodes. The second one is on the way that serialized frames are taken into account in the worst-case delay analysis.

  • RTCSA - The Trajectory Approach for AFDX FIFO networks revisited and corrected
    2014 IEEE 20th International Conference on Embedded and Real-Time Computing Systems and Applications, 2014
    Co-Authors: Olivier Cros, Laurent George
    Abstract:

    We consider the problem of dimensioning real-time AFDX FIFO networks with a worst-case end-to-end delay analysis. The state-of-the-art has considered several Approaches to compute these worst-case end-to-end delays. Among them, the Trajectory Approach has received more attention as it has been shown to provide tight end-to-end delay upper bounds. Recently, it has been proved that current Trajectory analysis can be optimistic for some corner cases, leading in its current form, to certification issues. In this paper, we first characterize the source of optimism in the Trajectory Approach on detailed examples. Then, we provide a correction to the identified problems. Two problems are solved: the first one is on the root cause of the underestimated time interval to compute delays of competing flows and a problem in the definition of the end-to-end delay computation. The second one is on the way that serialized frames are taken into account in the worst-case delay analysis.

Jean-luc Scharbarg - One of the best experts on this subject based on the ideXlab platform.

  • worst case backlog evaluation of avionics switched ethernet networks with the Trajectory Approach
    Euromicro Conference on Real-Time Systems, 2012
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Worst case backlog evaluation is a key issue to avoid under or over sizing of output port buffers for store-and-forward switches. Typically, the dimensioning of switches in the context of avionics is at least as important as the upper bounding of the end-to-end delays. This paper presents a new method based on the Trajectory Approach for backlog evaluation of output ports of AFDX switches. On an industrial AFDX configuration, this new method leads to an average buffer size reduction of 10\% compared to the existing Network Calculus Approach.

  • ECRTS - Worst-Case Backlog Evaluation of Avionics Switched Ethernet Networks with the Trajectory Approach
    2012 24th Euromicro Conference on Real-Time Systems, 2012
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Worst case backlog evaluation is a key issue to avoid under or over sizing of output port buffers for store-and-forward switches. Typically, the dimensioning of switches in the context of avionics is at least as important as the upper bounding of the end-to-end delays. This paper presents a new method based on the Trajectory Approach for backlog evaluation of output ports of AFDX switches. On an industrial AFDX configuration, this new method leads to an average buffer size reduction of 10\% compared to the existing Network Calculus Approach.

  • Applying Trajectory Approach with static priority queuing for improving the use of available AFDX resources
    2010
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (Avionics Full Duplex Switched Ethernet) standardized as ARINC 664 is a major upgrade for avionics systems. The mandatory certification implies a worst-case delay analysis of all the flows transmitted on the AFDX network. Up to now, this analysis is done thanks to a tool based on a Network Calculus Approach. The more recent Trajectory Approach has been proposed for the computation of worst-case response time in distributed systems. This paper shows how the worst-case delay analysis of an AFDX network can be improved using an optimized Trajectory Approach. This Approach, which implements static priority QoS policies, provides bound needed for deterministic avionics flows (high priority) and allows addition of (lower priority) non avionics flows.

  • Improving the worst-case delay analysis of an AFDX network using an optimized Trajectory Approach
    IEEE Transactions on Industrial Informatics, 2010
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    Avionics Full Duplex Switched Ethernet (AFDX) standardized as ARINC 664 is a major upgrade for avionics systems. The mandatory certification implies a worst-case delay analysis of all the flows transmitted on the AFDX network. Up to now, this analysis is done thanks to a tool based on a Network Calculus Approach. The more recent Trajectory Approach has been proposed for the computation of worst-case response time in distributed systems. This paper shows how the worst-case delay analysis of the AFDX can be improved using an optimized Trajectory Approach. The Network Calculus and the Trajectory Approaches are compared on a real avionics AFDX configuration. Moreover, an evaluation of an upper bound of the pessimism of each Approach is proposed.

  • Applying and optimizing Trajectory Approach for performance evaluation of AFDX avionics network
    ETFA 2009 - 2009 IEEE Conference on Emerging Technologies and Factory Automation, 2009
    Co-Authors: Henri Bauer, Jean-luc Scharbarg, Christian Fraboul
    Abstract:

    AFDX (avionics full duplex switched Ethernet) standardized as ARINC 664 is a major upgrade for avionics systems. But network delay analysis is required to evaluate end-to-end delay's upper bounds. The network calculus Approach, that has been used to evaluate such end-to-end delay upper bounds for certification purposes, is shortly described. In this paper we present how the Trajectory Approach can be applied to an AFDX avionics network. Moreover we explain how this Approach can be optimized in this context. We show that, on an industrial configuration, it outperforms existing end-to-end delays upper bounds.

Martin Karplus - One of the best experts on this subject based on the ideXlab platform.

  • reprint of semiclassical Trajectory Approach to photoisomerization
    Chemical Physics Letters, 2013
    Co-Authors: Arieh Warshel, Martin Karplus
    Abstract:

    A semiclassical Trajectory Approach has been used to study the cis–trans isomerization from the triplet state of butene-2. It is found that use of the full conformational space for the Trajectory calculation permits one to demonstrate that a simplified treatment is applicable; namely, once a transition from the triplet to the ground-state singlet has taken place, return to the triplet is prevented by rapid redistribution of the available energy. The method is used to determine the dependence of the isomerization rate on the essential parameters of the system.