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18141
29/06/2018

Semantic-enabled IoT Systems: an overview of recent initiatives and future directions

K.DRIRA

SARA

Conférence invitée : IEEE International Conference on Enabling Technologies: Infrastructures for Collaborative Enterprises ( WETICE ) 2018 du 27 juin au 29 juin 2018, Paris (France), Juin 2018, 1p. , N° 18141

Lien : https://hal.laas.fr/hal-01807442

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Abstract

IoT Systems provide advantages in various application domains. This fast-growing ecosystem is leading IoT towards a promising future. However, IoT systems expansion opportunities are not straightforward. A set of challenges should be overcome to enable IoT mass-scale deployment across various domains including protocol and data-levels semantic interoperability, complexity handling, and scalability management. This talk aims at giving an overview of these challenges. Recent international standardization and R&D initiatives will be investigated. Future directions will be highlighted. Autonomic IoT Systems; interoperability; semantic.

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18131
04/06/2018

Enhancing Middleware-based IoT Applications through Run-Time Pluggable QoS Management Mechanisms. Application to a oneM2M compliant IoT Middleware

C.OUEDRAOGO, S.MEDJIAH, C.CHASSOT, K.DRIRA

SARA

Revue Scientifique : Procedia Computer Science, Vol.130, pp.619-627, Juin 2018 , N° 18131

Lien : https://hal.archives-ouvertes.fr/hal-01797597

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Abstract

In the recent years, telecom and computer networks have witnessed new concepts and technologies through Network Function Virtualization (NFV) and Software-Defined Networking (SDN). SDN, which allows applications to have a control over the network, and NFV, which allows deploying network functions in virtualized environments, are two paradigms that are increasingly used for the Internet of Things (IoT). This Internet (IoT) brings the promise to interconnect billions of devices in the next few years rises several scientific challenges in particular those of the satisfaction of the quality of service (QoS) required by the IoT applications. In order to address this problem, we have identified two bottlenecks with respect to the QoS: the traversed networks and the intermediate entities that allows the application to interact with the IoT devices. In this paper, we first present an innovative vision of a “network function” with respect to their deployment and runtime environment. Then, we describe our general approach of a solution that consists in the dynamic, autonomous, and seamless deployment of QoS management mechanisms. We also describe the requirements for the implementation of such approach. Finally, we present a redirection mechanism, implemented as a network function, allowing the seamless control of the data path of a given middleware traffic. This mechanism is assessed through a use case related to vehicular transportation.

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18114
29/05/2018

Optimisation conjointe de la métrologie active et du routage : une approche markovienne

M.MOUCHET, S.VATON, O.BRUN, P.BELZARENA, I.AMIGO, B.PRABHU

IMT Atlantique, UBL, SARA, UdelaR

Manifestation avec acte : Rencontres Francophones sur la Conception de Protocoles, l’Évaluation de Performance et l’Expérimentation des Réseaux de Communication ( CORES ) 2018 du 28 mai au 29 mai 2018, Roscoff (France), Mai 2018, 4p. , N° 18114

Lien : https://hal.archives-ouvertes.fr/hal-01785870

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Résumé

Nous nous intéressons à l'optimisation des stratégies de monitoring actif dans le but d'optimiser le routage dans un ré-seau overlay. Notre approche est d'exploiter la stabilité des différentes routes en caractérisant les délais par des chaînes de Markov cachées (HMM) et de formaliser le problème comme un processus de décision markovien (MDP). Nous in-troduisons un modèle HMM pour caractériser les séries de RTT dans un réseau comme Internet. Puis nous formalisons le problème d'optimisation conjointe de la métrologie et du routage comme un MDP que nous résolvons avec une méthode de type Value Iteration. Enfin nous validons notre approche dans différents contextes. En particulier nous considérons un overlay de 30 ancres du réseau de mesure public RIPE Atlas. Nous montrons qu'en exploitant correctement la stabilité des performances des routes, il est possible de réduire le budget de mesure d'au moins 90% en ne perdant quasiment rien en termes de performance de routage.

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18116
07/05/2018

Scheduling in a single-server with state-dependent service rates

U.AYESTA, B.PRABHU, R.RIGHTER

IRIT-ENSEEIHT, SARA, Univ. of California

Rapport LAAS N°18116, Mai 2018, 15p.

Lien : https://hal.laas.fr/hal-01783136

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Abstract

We consider single-server scheduling to minimize holding costs where the capacity, or rate of service, depends on the number of jobs in the system, and job sizes become known upon arrival. In general, this is a hard problem, and counter-intuitive behavior can occur. For example, even with linear holding costs the optimal policy may be something other than SRPT or LRPT, it may idle, and it may depend on the arrival rate. We first establish an equivalence between our problem of deciding which jobs to serve when completed jobs immediately leave, and a problem in which we have the option to hold on to completed jobs and can choose when to release them, and in which we always serve jobs according to SRPT. We thus reduce the problem to determining the release times of completed jobs. For the clearing, or transient system, where all jobs are present at time 0, we give a complete characterization of the optimal policy and show that it is fully determined by the cost-to-capacity ratio. With arrivals, the problem is much more complicated, and we can obtain only partial results. We show that if the cost-to-capacity ratio is linear, then all non-idling policies yield the same average cost. We further characterize the optimal policy in some special cases. For example, we show that as long as capacity is increasing in the number of jobs, LRPT stochastically minimizes the mean busy period.

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18052
22/04/2018

Autonomous and Traffic-aware Scheduling for TSCH Networks

S.REKIK, N.BACCOUR, M.JMAIEL, K.DRIRA, L.GRIECO

ReDCAD Laboratory, SARA, Politecnico Bari

Revue Scientifique : Computer Networks, Vol.135, pp.201-212, Avril 2018 , N° 18052

Lien : https://hal.laas.fr/hal-01712826

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Abstract

Wireless Sensor Networks (WSNs) have been recognized as a promising communication technology for smart grid monitoring and control applications. However, the deployment of WSNs in smart grid brought new challenges that pertain to the harsh electrical grid nature, and the different and often contradicting communication requirements of smart grid monitoring applications. MAC protocols play a crucial role to meet the reliability and latency requirements of WSN-based smart grid communications. In particular, the IEEE 802.15.4 TSCH (Time Slotted Channel Hopping), the latest generation of low-power and highly reliable MAC protocols, orchestrates the medium access according to a time-frequency communication schedule. However, TSCH specification does not provide any practical solution for the establishment of the schedule. Orchestra is a recent scheduling solution for TSCH that brings significant advantages such as, the use of simple scheduling rules, the low signaling overhead, and the high delivery ratio. Despite its unique features, Orchestra has the limitation of computing the TSCH schedule at each node independently from its traffic load, which can drastically affect the communication delay. This limitation makes Orchestra not sufficiently convenient for several delay-sensitive smart grid applications. Further, the current TSCH specification does not support traffic differentiation (i.e. handle all packets equally regardless of their criticality levels). In this paper, we propose an enhanced Orchestra-based TSCH protocol, called e-TSCH-Orch, that dynamically adjusts time slots assignment according to traffic load and criticality level. The performance analysis of e-TSCH-Orch shows that it significantly reduces the communication delay compared to the original Orchestra-based TSCH, while preserving the low signaling overhead and the high packet delivery ratio.

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18086
19/04/2018

Reasoning on the edge or in the cloud ?

N.SEYDOUX, K.DRIRA, N.HERNANDEZ, T.MONTEIL

SARA, IRIT

Rapport LAAS N°18086, doi 10.1002/itl2.51, Avril 2018, 6p.

Lien : https://hal.laas.fr/hal-01768546

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Abstract

The emergence of the IoT and the Semantic Web of Things is leading to intensive cloud processing executing reasoning rules over large volumes of enriched data. However, the role of the cloud in existing approaches as a central point for both data processing and provisioning reduces scalability and introduces latency. This paper sketches a new approach for rule-based reasoning, enabling distributed rule evaluation on edge nodes and reducing the latency for IoT applications while avoiding the total dependence on a central node. This approach is evaluated in a simulated smart building.

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17591
13/04/2018

Editorial Message Track on Software-intensive Systems-of-Systems (SiSoS) of the 33rd ACM/SIGAPP Symposium On Applied Computing (SAC 2018)

K.DRIRA, F.OQUENDO, A.LEGAY, T.BATISTA

SARA, Univ Bretagne Sud, INRIA Rennes, UFRN, Brésil

Manifestation avec acte : Annual ACM Symposium on Applied Computing ( ACM-SAC ) 2018 du 09 avril au 13 avril 2018, Pau (France), Avril 2018, 3p. , N° 17591

Lien : https://hal.laas.fr/hal-01666389

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Abstract

Pervasiveness of networks has made possible to interconnect systems that were independently developed, operated, managed, and evolved, yielding a new kind of complex system, i.e. a system that is itself composed of systems, the so-called System-of-Systems (SoS). Software-intensive SoS (SiSoS) has become a hotspot in the last years, from both the research and industry viewpoints. Indeed, various aspects of our lives and livelihoods have progressively become dependent on some sort of Software-intensive SoS. This is the case of SiSoS found in different areas as diverse as energy, healthcare, manufacturing, and transportation; and applications that address societal needs, e.g. environmental monitoring, distributed energy grids, emergency coordination, global traffic control, and smart cities. Moreover, ubiquitous platforms such as the Internet of Things and nascent kinds of SoS such as Cyber-Physical SoSs are accelerating the deployment of Software-intensive SoS in the near future. Definitely, the unique characteristics of Software-intensive SoS raise a grand research challenge for the future of software-reliant systems in our industry and society due to its intrinsic features, among which evolutionary development and emergent behavior. Statistics The SiSoS Track received 22 regular paper submissions and 3 SRC submissions. Each submission was reviewed by three members of the Track Program Committee. The Track Program Committee selected 5 full papers out of the 22, giving an acceptance rate of 23%. These papers were selected based on originality, quality, soundness, and relevance to this conference track. Moreover, 2 poster papers have been accepted for publications in the proceedings of the conference. Key Topics This track fosters (but is not limited to) submissions in the following topics:

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18047
13/03/2018

A unifying framework for redundancy models: product form and impact of independence assumption

U.AYESTA, T.BODAS, I.M.VERLOOP

SARA, IRIT-ENSEEIHT

Rapport LAAS N°18047, Mars 2018, 21p.

Lien : https://hal.archives-ouvertes.fr/hal-01713937

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Abstract

In this paper, we present a unifying analysis for redundancy systems with cancel-on-start (c.o.s.) and cancel-on-complete (c.o.c.) with exponentially distributed service requirements. With c.o.s. (c.o.c.) all redundant copies are removed as soon as one of the copies starts (completes) service. As a consequence, c.o.s. does not waste any computing resources, as opposed to c.o.c.. We show that the c.o.s. model is equivalent to a queue-ing system with multi-type jobs and servers, which was analyzed in [1], and show that c.o.c. (under the assumption of i.i.d. copies) can be analyzed by a generalization of [1] where state-dependent departure rates are permitted. This allows us to show that the stationary distribution for both the c.o.c. and c.o.s. models have a product form. We give a detailed first-time analysis for c.o.s and derive a closed form expression for important metrics like mean number of jobs in the system, and probability of waiting. Comparing the performance of c.o.s. with that of c.o.c. gives the unexpected result (since c.o.s. does not waste any resources), that c.o.s. is worse in terms of mean number of jobs. The latter illustrates that the i.i.d. assumption (together with exponentially distributed requirements) might lead to conclusions that are qualitatively different from that observed in practice. We also show that the c.o.s. model is equivalent to Join-Shortest-Work queue with redundancy (JSW(d)). In the latter, an incoming job is dispatched to the server with smallest workload among d randomly chosen ones. Thus, all our results apply mutatis-mutandis to JSW(d).

142758
18037
07/03/2018

A Threshold Type Policy of a DTN Node Under Fixed Reward Incentive Mechanisms

T.SEREGINA, O.BRUN, B.PRABHU

ENAC, SARA

Rapport LAAS N°18037, Mars 2018, 17p.

Lien : https://hal.laas.fr/hal-01708410

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Abstract

The technology of Delay Tolerant Networks (DTN) has been designed to support communication in environments where connectivity is intermittent and communication delays can be very long. We focus on game-theoretic model for DTNs. We consider the model where the source proposes a fixed reward to persuade selfish mobile nodes to participate in relaying messages. The mobile relays can decide to accept or not the packet and then to drop the packet in the future. This game can be modelled as a partially-observable stochastic game. For two relays, we have shown that the optimal policies for the relays relates to the threshold type.

142664
18039
07/03/2018

Asymptotic Optimal Control of Markov-Modulated Restless Bandits

S.DURAN, I.M.VERLOOP

SARA, IRIT-ENSEEIHT

Rapport LAAS N°18039, Mars 2018, 25p.

Lien : https://hal.laas.fr/hal-01696329

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Abstract

This paper studies optimal control subject to changing conditions. This is an area that recently received a lot of attention as it arises in numerous situations in practice. Some applications being cloud computing systems where the arrival rates of new jobs fluctuate over time, or the time-varying capacity as encountered in power-aware systems or wireless downlink channels. To study this, we focus on a restless bandit model, which has proved to be a powerful stochastic optimization framework to model scheduling of activities. In particular, it has been extensively applied in the context of optimal control of computing systems. This paper is a first step to its optimal control when restless bandits are subject to changing conditions, the latter being modeled by Markov-modulated environments. We consider the restless bandit problem in an asymptotic regime, which is obtained by letting the population of bandits grow large, and letting the environment change relatively fast. We present sufficient conditions for a policy to be asymptotically optimal and show that a set of priority policies satisfies these. Under an indexability assumption, an averaged version of Whittle's index policy is proved to be inside this set of asymptotic optimal policies. The performance of the averaged Whittle's index policy is numerically evaluated for a multi-class scheduling problem in a wireless downlink subject to changing conditions. While keeping the number of bandits constant, we observe that the average Whittle index policy becomes close to optimal as the speed of the modulated environment increases.

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