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Aurelien Babarit - One of the best experts on this subject based on the ideXlab platform.

  • Discrete Control of resonant wave energy devices
    Philosophical Transactions of the Royal Society A, 2012
    Co-Authors: A H Clement, Aurelien Babarit
    Abstract:

    Aiming at amplifying the energy productive motion of wave energy converters (WECs) in response to irregular sea waves, the strategies of Discrete Control presented here feature some major advantages over continuous Control, which is known to require, for optimal operation, a bidirectional power take-off able to re-inject energy into the WEC system during parts of the oscillation cycles. Three different Discrete Control strategies are described: latching Control, declutching Control and the combination of both, which we term latched-operating-declutched Control. It is shown that any of these methods can be applied with great benefit, not only to mono-resonant WEC oscillators, but also to bi-resonant and multi-resonant systems. For some of these applications, it is shown how these three Discrete Control strategies can be optimally defined, either by analytical solution for regular waves, or numerically, by applying the optimal command theory in irregular waves. Applied to a model of a seven degree-of-freedom system (the SEAREV WEC) to estimate its annual production on several production sites, the most efficient of these Discrete Control strategies was shown to double the energy production, regardless of the resource level of the site, which may be considered as a real breakthrough, rather than a marginal improvement.

  • Discrete Control of resonant wave energy devices
    Philosophical Transactions of the Royal Society A: Mathematical Physical and Engineering Sciences, 2012
    Co-Authors: A H Clement, Aurelien Babarit
    Abstract:

    Aiming at amplifying the energy productive motion of wave energy converters (WEC) in response to irregular sea waves, the strategies of Discrete Control presented here feature some major advantages over continuous Control which is known to require, for optimal operation, a bidirectional power take-off (PTO) able to re-inject energy into the WEC system during parts of the oscillation cycles. Three different Discrete Control strategies are described: latching Control, declutching Control, and the combination of both, which we term LOD (Latched-Operating-Declutched) Control. It is shown that any of these methods can be applied with great benefit, not only to mono-resonant WEC oscillators, but also to bi-resonant and multi-resonant systems. For some of these applications, it is shown how these three Discrete Control strategies can be optimally defined, either by analytical solution for regular waves, or numerically, by applying the optimal command theory in irregular waves. Applied to a model of a 7 degree-of-freedom system (the SEAREV WEC) to estimate its annual production on several production sites, the most efficient of these Discrete Control strategies was shown to double the energy production, regardless of the resource level of the site, which may be considered as a real breakthrough, rather than a marginal improvement.

Eric Rutten - One of the best experts on this subject based on the ideXlab platform.

  • Discrete Control-Based Design of Adaptive and Autonomic Computing Systems
    2015
    Co-Authors: Gwenaël Delaval, Jean-philippe Diguet, Abdoulaye Gamatié, Noël De Palma, Soguy Mak-karé Gueye, Hervé Marchand, Eric Rutten
    Abstract:

    This invited paper makes an overview of our works addressing Discrete Control-based design of adaptive and reconfigurable computing systems, also called autonomic computing. They are characterized by their ability to switch between different execution modes w.r.t. application and functionality, mapping and deployment, or execution architecture. The Control of such reconfigurations or adaptations is a new application domain for Control theory, called feedback computing. We approach the problem with a programming language supported approach, based on synchronous languages and Discrete Control synthesis. We concretely use this approach in FPGA-based reconfigurable architectures, and in the coordination of administration loops.

  • ICDCIT - Discrete Control-Based Design of Adaptive and Autonomic Computing Systems
    Distributed Computing and Internet Technology, 2015
    Co-Authors: Gwenaël Delaval, Jean-philippe Diguet, Abdoulaye Gamatié, Noël De Palma, Soguy Mak-karé Gueye, Hervé Marchand, Eric Rutten
    Abstract:

    This invited paper makes an overview of our works addressing Discrete Control-based design of adaptive and reconfigurable computing systems, also called autonomic computing. They are characterized by their ability to switch between different execution modes w.r.t. application and functionality, mapping and deployment, or execution architecture. The Control of such reconfigurations or adaptations is a new application domain for Control theory, called feedback computing. We approach the problem with a programming language supported approach, based on synchronous languages and Discrete Control synthesis. We concretely use this approach in FPGA-based reconfigurable architectures, and in the coordination of administration loops.

  • Discrete Control for ensuring consistency between multiple autonomic managers
    Journal of Cloud Computing: Advances Systems and Applications, 2013
    Co-Authors: Soguy Mak Karé Gueye, Eric Rutten, Alain Tchana, Noël De Palma, Daniel Hagimont
    Abstract:

    The increasing complexity of computer systems has led to the automation of administration functions, in the form of autonomic managers. Today many autonomic managers are available but they mostly address a specific administration aspect which makes necessary their coexistence for a complete autonomic system management. However, coordinating them is necessary for proper and effective global administration. Such coordination can be considered as a problem of synchronization and logical Control of managers actions. We therefore investigate the use of reactive models with events and states, and Discrete Control techniques to solve this problem. This paper presents an application of the latter approach for coordinating autonomic managers addressing resource optimization, in the perspective of green computing. The managers Control server provisioning (self-sizing manager) and CPU frequency (Dvfs manager), and the coordination Controller Controls the managers actions so as to avoid incoherent management decisions. The coordination Controller is designed using synchronous programming and Discrete Controller synthesis (DCS) which are well-suited for the design of reactive systems. Experimental results are presented to evaluate the efficacy of the approach.

  • Autonomic Management of Reconfigurable Embedded Systems using Discrete Control: Application to FPGA
    2013
    Co-Authors: Eric Rutten, Jean-philippe Diguet, Nicolas Le Griguer, Abdoulaye Gamatié
    Abstract:

    This paper targets the autonomic management of dynamically partially reconfigurable hardware architectures based on FPGAs. Such hardware-level autonomic computing has been less often studied than at software-level. We consider Control techniques to model the considered behaviours of the computing system and derive a Controller for the Control objective enforcement. Discrete Control modelled with Labelled Transition Systems is employed in this paper. Such models are amenable to Discrete Controller Synthesis algorithms that can automatically generate a Controller enforcing the correct behaviours of a Controlled system. A general modelling framework is proposed for the Control of FPGA based computing systems. We consider system application described as task graphs and FPGA as a set of reconfigurable areas that can be dynamically partially reconfigured to execute tasks. We encode the computation of an autonomic manager as a DCS problem w.r.t. multiple constraints and objectives e.g., mutual exclusion of resource uses, power cost minimization. We validate our models and manager computations by using the BZR language and an experimental demonstrator implemented on a Xilinx FPGA platform.

  • Coordinating multiple administration loops using Discrete Control
    Operating Systems Review, 2013
    Co-Authors: Soguy Mak-karé Gueye, Eric Rutten, Noël De Palma, Alain Tchana
    Abstract:

    The increasing complexity of computer systems has led to the automation of administration functions, in the form of autonomic managers. One important aspect requiring such management is the issue of energy consumption of computing systems, in the perspective of green computing. As these managers address each a specific aspect, there is a need for using several managers to cover all the domains of administration. However, coordinating them is necessary for proper and effective global administration. Such coordination is a problem of synchronization and logical Control of administration operations that can be applied by autonomous managers on the managed system at a given time in response to events observed on the state of this system. We therefore propose to investigate the use of reactive models with events and states, and Discrete Control techniques to solve this problem. In this paper, we illustrate this approach by integrating a Controller obtained by synchronous programming, based on Discrete Controller Synthesis, in an autonomic system administration infrastructure. The role of this Controller is to orchestrate the execution of reconfiguration operations of all administration policies to satisfy properties of logical consistency. We apply this approach to coordinate three managers : two energy-aware ones, which Control server provisioning and processor frequency, and a repair manager.

A H Clement - One of the best experts on this subject based on the ideXlab platform.

  • Discrete Control of resonant wave energy devices
    Philosophical Transactions of the Royal Society A, 2012
    Co-Authors: A H Clement, Aurelien Babarit
    Abstract:

    Aiming at amplifying the energy productive motion of wave energy converters (WECs) in response to irregular sea waves, the strategies of Discrete Control presented here feature some major advantages over continuous Control, which is known to require, for optimal operation, a bidirectional power take-off able to re-inject energy into the WEC system during parts of the oscillation cycles. Three different Discrete Control strategies are described: latching Control, declutching Control and the combination of both, which we term latched-operating-declutched Control. It is shown that any of these methods can be applied with great benefit, not only to mono-resonant WEC oscillators, but also to bi-resonant and multi-resonant systems. For some of these applications, it is shown how these three Discrete Control strategies can be optimally defined, either by analytical solution for regular waves, or numerically, by applying the optimal command theory in irregular waves. Applied to a model of a seven degree-of-freedom system (the SEAREV WEC) to estimate its annual production on several production sites, the most efficient of these Discrete Control strategies was shown to double the energy production, regardless of the resource level of the site, which may be considered as a real breakthrough, rather than a marginal improvement.

  • Discrete Control of resonant wave energy devices
    Philosophical Transactions of the Royal Society A: Mathematical Physical and Engineering Sciences, 2012
    Co-Authors: A H Clement, Aurelien Babarit
    Abstract:

    Aiming at amplifying the energy productive motion of wave energy converters (WEC) in response to irregular sea waves, the strategies of Discrete Control presented here feature some major advantages over continuous Control which is known to require, for optimal operation, a bidirectional power take-off (PTO) able to re-inject energy into the WEC system during parts of the oscillation cycles. Three different Discrete Control strategies are described: latching Control, declutching Control, and the combination of both, which we term LOD (Latched-Operating-Declutched) Control. It is shown that any of these methods can be applied with great benefit, not only to mono-resonant WEC oscillators, but also to bi-resonant and multi-resonant systems. For some of these applications, it is shown how these three Discrete Control strategies can be optimally defined, either by analytical solution for regular waves, or numerically, by applying the optimal command theory in irregular waves. Applied to a model of a 7 degree-of-freedom system (the SEAREV WEC) to estimate its annual production on several production sites, the most efficient of these Discrete Control strategies was shown to double the energy production, regardless of the resource level of the site, which may be considered as a real breakthrough, rather than a marginal improvement.

Cunchen Gao - One of the best experts on this subject based on the ideXlab platform.

Prasant Mohapatra - One of the best experts on this subject based on the ideXlab platform.

  • Real-time scheduling method for networked Discrete Control systems
    Control Engineering Practice, 2009
    Co-Authors: Dong-sung Kim, Dong-hyuk Choi, Prasant Mohapatra
    Abstract:

    This paper proposes a new scheduling method to obtain a maximum allowable delay bound for a scheduling of networked Discrete Control systems. The proposed method is formulated in terms of linear matrix inequalities (LMI) and can give a much less conservative delay bound than the existing methods. An event based network scheduling method is presented based on the delay bound obtained through the proposed method, and it can adjust the sampling period to allocate identical utilization to each Control loop. The presented method can handle sporadic emergency data, periodic data, and non-real-time data.