### Some news

- Welcome to the Real-Time Systems and Energy efficiency Team !

### Few Words

#### Real-Time Scheduling

A real-time system is a reactive, deterministic system whose proper functioning depends not only on the logical accuracy of the calculated data, but also on the respect of certain temporal constraints. In scheduling theory, a real-time system is usually formalized by a set of tasks to be executed on a platform. A scheduling algorithm must determine the order of tasks that optimizes the use of the platform while respecting the time constraints. We have studied the performance of fixed priority scheduling algorithms at task level and job level as well as the cost of scheduling for sporadic task templates and acyclic task graphs.

We were also interested in real-time scheduling for energy harvesting systems (Energy Harvesting System). We have proposed a task model for this problem and a scheduling algorithm for which we proved optimality in the class of fixed priority algorithms in the case and where the system is composed only of energy consuming tasks and proposed sufficient scheduling tests in a more general case. We have also studied probabilistic approaches for the modeling and analysis of real-time scheduling problems, in the case of mixed criticality systems and for time sensitivity analysis of real-time systems.

We have also studied different interconnection systems and networks such as Network on Chip (NoC) and real-time Ethernet networks in order to characterize the worst end-to-end response time.

We have proposed arbitration mechanisms in the NoC to guarantee the predictability, security and criticality of the flows passing from one core to the other (in context Manycoeur) through a NoC. A first contribution is an adaptation of the trajectory approach traditionally used in avionics networks (AFDX) to calculate the worst crossing time of NoC. The second contribution is a mechanism for detecting DoS attacks and mitigating their impact by a mixed criticality approach where the criticality of a stream reflects its level of security.

#### Energy Efficiency

Due to rising energy costs and environmental concerns, centralized power generation systems are restructuring to take advantage of decentralized energy production. Microgrids are considered a possible solution for deploying Distributed Energy Resources (DER). We are interested in the problem of energy management in an industrial microgrid, our approach is to divide the energy management of microgrids into two phases: the supply and the demand sides.

- On the supply side, we have proposed solutions for distributed energy source modeling and for the mitigation of DER fluctuations by proposing a model based on Network Calculus (NC) service curve concepts and Gaussian smoothing. We determine the minimum amount of power that the DERs can generate and their aggregation gives us the total power output in the microgrid with or without a battery to compensate for the prediction errors.
- On the demand side, the goal is to reduce energy costs through Demand Side Management (DSM) approaches such as Demand Response (DR) and Energy Efficiency (EE). Since industrial processes are energy-hungry consumers, we have been interested in reducing the energy consumption of synchronous / asynchronous production lines so that this has the least impact on the throughput of production. In this framework we have proposed a framework, called DR-Mgmt, which allows to first model the temporal behavior of the production lines by PLCs and waiting queues. Then, it searchs for optimal or near-optimal scheduling based on combinatorial optimization techniques.

### Last 10 publications

See our full publications list- titre
- A New Mapping Methodology for Coarse-Grained Programmable Systolic Architectures
- auteur
- Elias Barbudo, Eva Dokladalova, Thierry Grandpierre, Laurent George
- article
*22nd International Workshop on Software and Compilers for Embedded Systems (SCOPES 2019)*, May 2019, St Goar, Germany. ⟨10.1145/3323439.3323982⟩- Accès au texte intégral et bibtex

- titre
- A Practical Sub-Optimal Solution for the Dual Priority Scheduling Problem
- auteur
- Tristan Fautrel, Laurent George, Joël Goossens, Damien Masson, Paul Rodriguez
- article
*13th International Symposium on Industrial Embedded Systems (SIES'2018)*, Jun 2018, Gratz, Austria- Accès au bibtex

- titre
- Stretching algorithm for global scheduling of real-time DAG tasks
- auteur
- Manar Qamhieh, Laurent George, Serge Midonnet
- article
*Real-Time Systems*, Springer Verlag, 2018, ⟨10.1007/s11241-018-9311-1⟩- Accès au bibtex

- titre
- A mapping tool for configurable pipeline co-processors
- auteur
- Elias Barbudo, Eva Dokladalova, Thierry Grandpierre, Laurent George
- article
*Colloque National du GDR SoC-SiP*, GDR-SOC-SIP, Jun 2018, Paris, France- Accès au texte intégral et bibtex

- titre
- Demand response scheduling in production lines constrained by available power
- auteur
- Alemayehu Desta, Hakim Badis, Laurent George
- article
*IEEE International Conference on Communications (IEEE ICC) 2018 Workshop - ICT4SG*, May 2018, Kansas City, MO, United States- Accès au bibtex

- titre
- Selective Real-Time Data Emission in Mobile Intelligent Transport Systems
- auteur
- Laurent George, Damien Masson, Vincent Nélis
- article
*5th International Workshop on Mixed Criticality Systems*, Dec 2017, Paris, France- Accès au texte intégral et bibtex

- titre
- An efficient production scheduling based on queuing theory in systems with synchronous part transfer during a demand response event
- auteur
- Alemayehu Desta, Hakim Badis, Laurent George, Pierre Courbin
- article
*2017 IEEE International Conference on Smart Grid Communications (SmartGridComm)*, Oct 2017, Dresden, Germany. ⟨10.1109/SmartGridComm.2017.8340724⟩- Accès au bibtex

- titre
- Smoothing of renewable energy generation using Gaussian-based method with power constraints
- auteur
- Alemayehu Desta, Laurent George, Pierre Courbin, Vincent Sciandra
- article
*Energy Procedia*, Elsevier, 2017, 134, pp.171 - 180. ⟨10.1016/j.egypro.2017.09.555⟩- Accès au bibtex

- titre
- Chapter 1: A Survey of Switched Ethernet Solutions for Real-time Audio/Video Communications
- auteur
- Xiaoting Li, Laurent George
- article
*ISTE Press - Elsevier*, 2017, Building Wireless Sensor Networks - 1st Edition, ISBN: 9781785482748- Accès au bibtex

- titre
- A Mixed Criticality Approach for Industrial Smart Energy Management and Demand Response
- auteur
- Alemayehu Desta, Hakim Badis, Laurent George, Pierre Courbin
- article
*8th Real-Time Scheduling Open Problems Seminar (RTSOPS)*, Jun 2017, Dubrovnik, Croatia- Accès au bibtex