Le présent article a pour objectif de décrire des contributions de recherche collaborative entre ... more Le présent article a pour objectif de décrire des contributions de recherche collaborative entre l'IUT de Nantes et l'IUT de Saida au Liban. L'initiation de cette collaboration a ´ eté concommittente il y a dix ans avec celle d'un nouvel axe de recherche du LS2N centré sur les systèmes temps réel autonomes enénergieenénergie. Ils se rapportè a la conception des infrastructures logicielles spécifiques pour assurer ce que l'on nomme la neutraliténeutralitéénergétique, en particulier dans les noeuds de capteur sans fil, principaux maillons de l'Internet des Objets. Par nos travaux, nous montrons notamment comment les stratégies d'ordonnancement temps réel peuvent impacter favorablement la neutraliténeutralitéénergétique, comment celles-ci peuventéviterpeuventéviter la famine d'´ energie ou le gaspillage d'´ energie et comment elles garantissent des résultats de calcul sous contraintes temporelles strictes. Mots-clés-capteur sans fil autonome, récupér...
2020 International Conference on Intelligent Systems and Computer Vision (ISCV), 2020
In many self-powered monitoring systems that support real-time applications, temporal guarantees ... more In many self-powered monitoring systems that support real-time applications, temporal guarantees are crucial. Energy-harvesting and energy-neutral sensing systems are such an example. In this paper, we survey selected prior work that addresses real-time issues in such systems. The survey outlines the requirements for optimal scheduling (i.e. clairvoyance and iding capabilities). The covered topics include fundamental results about EDF-based real-time scheduling, and real-time scheduling analysis of periodic task sets in energy harvesting systems. A detailed review is provided covering EDF and ED-H scheduling algorithms, their practicability, and the latest results from robustness and competitiveness investigations. The survey identifies key research challenges and likely productive research directions to help design and validation of any self-powered sensing system.
2020 International Conferences on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData) and IEEE Congress on Cybermatics (Cybermatics), 2020
This paper proposes new scheduling approaches for servicing aperiodic tasks in a real-time system... more This paper proposes new scheduling approaches for servicing aperiodic tasks in a real-time system powered by renewable energy. We show that, the arriving aperiodics, if serviced naively, could cause the system to run out of power. We describe how to adjust the classical BG (Background Server) and TBS (Total Bandwidth Server) so as to work together with two energy-aware real-time schedulers, namely Green-RTO and Green-BWP. Their objective is threefold: (i) to guarantee a prespecified Quality of Service (QoS) level - measured in terms of success deadline ratio - for the periodic tasks, (ii) to minimize the response time of the aperiodic tasks, and (iii) to achieve perpetual energy autonomy for the whole system. We describe the results of both theoretical and experimental studies in order to bring to light the effectiveness of these aperiodic task servers which are specifically suited to firm real-time energy harvesting systems.
2017 Sensors Networks Smart and Emerging Technologies (SENSET), 2017
This paper deals with the scheduling issue that arises in small energy harvesting devices. Such o... more This paper deals with the scheduling issue that arises in small energy harvesting devices. Such ones support both soft aperiodic tasks and hard deadline periodic tasks. The scheduler has to produce a sequence without deadline missing and with no energy starvation while reducing the response time of aperiodic tasks. The proposed servers, called BES (Background with Energy Surplus server) and BEP (Background with Energy Preserving server), are based on the classical background server and on the optimal ED-H scheduler. Experimental results demonstrate that the BEP server offers a substantial improvement over the BES server in terms of the aperiodic responsiveness under various time and energy settings.
Cryptosystems require a very good and secure source of randomness for their security. Such a sour... more Cryptosystems require a very good and secure source of randomness for their security. Such a source is extremely difficult to obtain in practice. Hence, developing a secure pseudo-random number generator reveals necessary. In this paper, we propose a new pseudo chaotic number generator. The proposed structure integrates three discrete chaotic maps: PWLCM, Skewtent and Logistic, which are weakly coupled and implemented with finite precision N=32 bits. It also includes a chaotic multiplexing technique. The experiment results and statistical analysis prove the robustness of the proposed generator as well as its efficiency in terms of computation time in comparison with know chaotic generators of the literature. Based on the previous structure, a random number generator that uses Linux generator has been designed : "/dev/urandom".
Le présent article a pour objectif de décrire des contributions de recherche collaborative entre ... more Le présent article a pour objectif de décrire des contributions de recherche collaborative entre l'IUT de Nantes et l'IUT de Saida au Liban. L'initiation de cette collaboration a ´ eté concommittente il y a dix ans avec celle d'un nouvel axe de recherche du LS2N centré sur les systèmes temps réel autonomes enénergieenénergie. Ils se rapportè a la conception des infrastructures logicielles spécifiques pour assurer ce que l'on nomme la neutraliténeutralitéénergétique, en particulier dans les noeuds de capteur sans fil, principaux maillons de l'Internet des Objets. Par nos travaux, nous montrons notamment comment les stratégies d'ordonnancement temps réel peuvent impacter favorablement la neutraliténeutralitéénergétique, comment celles-ci peuventéviterpeuventéviter la famine d'´ energie ou le gaspillage d'´ energie et comment elles garantissent des résultats de calcul sous contraintes temporelles strictes. Mots-clés-capteur sans fil autonome, récupér...
2020 International Conference on Intelligent Systems and Computer Vision (ISCV), 2020
In many self-powered monitoring systems that support real-time applications, temporal guarantees ... more In many self-powered monitoring systems that support real-time applications, temporal guarantees are crucial. Energy-harvesting and energy-neutral sensing systems are such an example. In this paper, we survey selected prior work that addresses real-time issues in such systems. The survey outlines the requirements for optimal scheduling (i.e. clairvoyance and iding capabilities). The covered topics include fundamental results about EDF-based real-time scheduling, and real-time scheduling analysis of periodic task sets in energy harvesting systems. A detailed review is provided covering EDF and ED-H scheduling algorithms, their practicability, and the latest results from robustness and competitiveness investigations. The survey identifies key research challenges and likely productive research directions to help design and validation of any self-powered sensing system.
2020 International Conferences on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData) and IEEE Congress on Cybermatics (Cybermatics), 2020
This paper proposes new scheduling approaches for servicing aperiodic tasks in a real-time system... more This paper proposes new scheduling approaches for servicing aperiodic tasks in a real-time system powered by renewable energy. We show that, the arriving aperiodics, if serviced naively, could cause the system to run out of power. We describe how to adjust the classical BG (Background Server) and TBS (Total Bandwidth Server) so as to work together with two energy-aware real-time schedulers, namely Green-RTO and Green-BWP. Their objective is threefold: (i) to guarantee a prespecified Quality of Service (QoS) level - measured in terms of success deadline ratio - for the periodic tasks, (ii) to minimize the response time of the aperiodic tasks, and (iii) to achieve perpetual energy autonomy for the whole system. We describe the results of both theoretical and experimental studies in order to bring to light the effectiveness of these aperiodic task servers which are specifically suited to firm real-time energy harvesting systems.
2017 Sensors Networks Smart and Emerging Technologies (SENSET), 2017
This paper deals with the scheduling issue that arises in small energy harvesting devices. Such o... more This paper deals with the scheduling issue that arises in small energy harvesting devices. Such ones support both soft aperiodic tasks and hard deadline periodic tasks. The scheduler has to produce a sequence without deadline missing and with no energy starvation while reducing the response time of aperiodic tasks. The proposed servers, called BES (Background with Energy Surplus server) and BEP (Background with Energy Preserving server), are based on the classical background server and on the optimal ED-H scheduler. Experimental results demonstrate that the BEP server offers a substantial improvement over the BES server in terms of the aperiodic responsiveness under various time and energy settings.
Cryptosystems require a very good and secure source of randomness for their security. Such a sour... more Cryptosystems require a very good and secure source of randomness for their security. Such a source is extremely difficult to obtain in practice. Hence, developing a secure pseudo-random number generator reveals necessary. In this paper, we propose a new pseudo chaotic number generator. The proposed structure integrates three discrete chaotic maps: PWLCM, Skewtent and Logistic, which are weakly coupled and implemented with finite precision N=32 bits. It also includes a chaotic multiplexing technique. The experiment results and statistical analysis prove the robustness of the proposed generator as well as its efficiency in terms of computation time in comparison with know chaotic generators of the literature. Based on the previous structure, a random number generator that uses Linux generator has been designed : "/dev/urandom".
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