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Papers by Abdelfettah Belghith

Abstract Quality of service (QoS) provisioning generally assumes more than one QoS measure which ... more Abstract Quality of service (QoS) provisioning generally assumes more than one QoS measure which implies that QoS routing can be categorized as an instance of routing subject to multiple constraints: delay-jitter, bandwidth, cost, etc. We study the problem of ...

2014 IEEE International Conference on Communications (ICC), 2014

The number of vehicles on roads keeps increasing continuously, making the management of traffic f... more The number of vehicles on roads keeps increasing continuously, making the management of traffic flow, especially in big cities more and more challenging. One of the key enablers for having smooth traffic flows and better mobility is to rely on real-time traffic monitoring systems. These systems allow road operators to implement intelligent traffic management strategies such as the dynamic adjustment of timing and phasing of traffic lights and the adaptive road congestion charging. Moreover, better informed travelers will plan smartly their journeys and hence potentially contribute in reducing traffic jams. Traditional real-time traffic monitoring usually get real-time data from GPSequipped fleets and fixed sensors installed in specific locations. In this paper, a new real-time traffic monitoring based on emerging vehicular communication systems is proposed. The system enables traffic monitoring with higher reliability, accuracy, and granularity. The cluster-based V2X traffic data collection mechanism is able to gather more than 99% of the available data and reduce the overhead to one quarter when compared to other approaches.

ICT 2013, 2013

ABSTRACT Car to car communication has been getting considerable interest for the last decade, esp... more ABSTRACT Car to car communication has been getting considerable interest for the last decade, especially in the last few years where market introduction phase is approaching fast. A variety of applications will be enabled thanks to car to car communication. Considerable efforts have been already spent in designing and developing efficient broadcast communication systems to support not only safety applications but also infotainment and traffic efficiency applications and services. This leads in less efforts spent on unicast communication solutions that support not only infotainment applications but also traffic efficiency services. To fill this gap, an advanced location service is proposed in this contribution to enable efficient and reliable unicast communications. This solution mixes between short range communication (over 5.9 GHz) and cellular-based communication. The proposed solution has been validated through extensive simulations using a simulation platform which is compliant to latest related standards.

2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2013

ABSTRACT This paper introduces CrossWalk, a novel integrated cross-layer medium access control/ro... more ABSTRACT This paper introduces CrossWalk, a novel integrated cross-layer medium access control/routing protocol based on a receiver-oriented contention resolution mechanism for data dissemination in wireless sensor networks. Traditional approaches for data dissemination such as flooding or simple random walks suffer respectively from a large message forwarding overhead and an excessively long cover time. In this scope, CrossWalk, based on biased random walks, aims to achieve a convenient cover time at the cost of a reasonable overhead. In particular, we demonstrate by an analytical study that the proposed biasing strategy based on a decreasing truncated geometric distribution over a fixed contention window favors a data packet to progress-in a unicast fashion-towards nodes in less explored vicinity by making them more likely to win the contention for the medium access. We therefore show by extensive simulations that CrossWalk outperforms common random walks in terms of partial coverage and efficient network resources consumption by making less redundant message transmissions.

2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2013

ABSTRACT This paper introduces CrossWalk, a novel integrated cross-layer medium access control/ro... more ABSTRACT This paper introduces CrossWalk, a novel integrated cross-layer medium access control/routing protocol based on a receiver-oriented contention resolution mechanism for data dissemination in wireless sensor networks. Traditional approaches for data dissemination such as flooding or simple random walks suffer respectively from a large message forwarding overhead and an excessively long cover time. In this scope, CrossWalk, based on biased random walks, aims to achieve a convenient cover time at the cost of a reasonable overhead. In particular, we demonstrate by an analytical study that the proposed biasing strategy based on a decreasing truncated geometric distribution over a fixed contention window favors a data packet to progress-in a unicast fashion-towards nodes in less explored vicinity by making them more likely to win the contention for the medium access. We therefore show by extensive simulations that CrossWalk outperforms common random walks in terms of partial coverage and efficient network resources consumption by making less redundant message transmissions.

2012 IEEE Vehicular Technology Conference (VTC Fall), 2012

ABSTRACT

Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems - MSWiM '13, 2013

ABSTRACT In recent years, the use of random walks (RW) for data forwarding in wireless sensor net... more ABSTRACT In recent years, the use of random walks (RW) for data forwarding in wireless sensor networks (WSN) has gained a lot of popularity. However, a negative effect is often caused by the fact that a completely uniform random choice of the next hop during the walk translates into a reduced progress towards the sink node, thereby yielding a long latency. Several strategies are proposed to attenuate this problem. Most of them are characterized by their dependence on state information stored in sensor nodes in order to bias the direction of the walk towards the target. Such information require additional capabilities and it is costly in terms of complexity and energy, which is inherently problematical in WSN. This leads to a tradeoff between mutually contradictory goals and raises the question as to what extent biasing RW can affect the performance of the data forwarding scheme. This question is our primary motivation in investigating the problem of biasing RW based data forwarding from a pure analytical perspective.

2013 9th International Wireless Communications and Mobile Computing Conference (IWCMC), 2013

ABSTRACT

2012 IEEE International Conference on RFID-Technologies and Applications (RFID-TA), 2012

ABSTRACT

Nous nous intéressons à l'étude des phénomènes de transfert de chaleur dans un échangeur à calopo... more Nous nous intéressons à l'étude des phénomènes de transfert de chaleur dans un échangeur à caloporteurs fluide et solide, formé de compartiments remplis de fluide et de milieux poreux et dont les frontières horizontales sont soumises à des flux de chaleur non uniforme. Le caloporteur fluide, saturant le milieu poreux, est injecté à une vitesse et une température constantes et dont les particules fluides sont considérées en hors équilibre thermique local avec les particules solides composantes du milieu poreux. Cet écoulement est régi par les équations de conservation de masse et de quantité de mouvement de Darcy-Brinkman et celles de la conservation de l'énergie dans les deux phases fluides et solides. Nous proposons d'analyser leurs effets sur le régime d'écoulement. Les calculs sont effectués pour une seul perméabilité de la grille poreuse (nombre de Darcy Da=10 -4 ), le nombre de Reynolds, Re =10 et un nombre de Rayleigh fixé à Ra=10 4 .

Power conservation techniques are of utmost importance in Wirreless LANs to prolong the life of m... more Power conservation techniques are of utmost importance in Wirreless LANs to prolong the life of mobile stations relying on portable limited enrgy batteries. A power conservation mechanism should provide the maximum energy saving at light traffic loads, yet thrives to deliver data as much as possible in high traffic conditions. In this paper, we investigate the inherent functional properties of the infrastructure mode IEEE 802.11 Power Saving Mechanism (PSM). We show through extensive simulations that PSM stands very short and does not level up to its design objectives. PSM blocks the network traffic flow, yet it does not adequately save energy as supposed to be. We show that at high traffic loads, PSM exhibits a very poor throughput and excessive power consumption per delivered data frame. We therefore investigate the inherent properties that made PSM inefficient and propose two different enhancements called State Aware PSM (SA-PSM) and Once Poll PSM (OP-PSM). We show through extensive simulations that tangible improvements are attained. These enhancements save power as much as PSM for light traffic loads and deliver as much a throughput as when no power saving mechanism is deployed. Virtually at all traffic loads, OP-PSM and SA-PSM nicely outperform PSM and provide a much less average time spent by a data frame from its generation at the source station until its delivery to the destination station.

International Journal of Heat and Mass Transfer

Les transferts coupl es de mati ere et de chaleur par convection naturelle sont etudi es en r egi... more Les transferts coupl es de mati ere et de chaleur par convection naturelle sont etudi es en r egime permanent num eriquement et exp erimentalement au cours de l' evapo-condensation dans une cavit e rectangulaire de rapport g eom etrique 10. Une paroi sur laquelle ruisselle un ®lm d'eau est soumise a une densit e de¯ux de chaleur constante tandis que la paroi parall ele est maintenue a une temp erature basse. L' etude vise de mani ere g en erale a l'am elioration de la distillation dans les syst emes de dessalement solaire. Les equations sont r esolues par une m ethode de volumes ®nis et fournissent les champs de temp erature, concentration et vitesse dans la phase gazeuse pour di erentes densit es du¯ux de chaleur. L' etude par simulation a permis de quanti®er les in¯uences sur le d ebit moyen de distillation de nombreux param etres tels que le¯ux de chauage, la temp erature et le d ebit de l'eau d'alimentation, la temp erature de la paroi de condensation, le facteur de forme de la cellule. Les r esultats exp erimentaux obtenus sur une cellule pilote concernant la production d'eau dessal ee confortent les r esultats de simulation. Pour une densit e de¯ux de chaleur de 1000 W m À2 , un rendement de 0,7 est couramment atteint. Ó 2001 Elsevier Science Ltd. All rights reserved.

Ad-hoc networks have received significant attention over the last few years as these emerging net... more Ad-hoc networks have received significant attention over the last few years as these emerging networks provide a fast deployable multi-hop wireless infrastructure for a growing number of applications when a wireline network is neither available nor economical to build. To overcome the scalability problem, creating hierarchies among the nodes seems to be a promising approach and an effective way to organize the network as the number of nodes increases. In this paper, we present a novel distributed clustering algorithm for ad-hoc networks. Our algorithm is based on a synchronized and layered process. Its main objective is to minimize the number of control messages exchanged during the clustering process.We evaluate our algorithm using the Visidia simulation test bed and show that it outperforms one of the most known clustering algorithms in minimizing both the number of control messages and the number of elected clusterheads.

The intrinsic characteristics of ad hoc networks, such as the frequent connectivity changes and t... more The intrinsic characteristics of ad hoc networks, such as the frequent connectivity changes and the strict bandwidth and power constraints, impose further challenges, especially for routing tasks. Establishing and maintaining routes are hard tasks in a dynamic environment, in particular for large and dense networks where the control overhead induced by routing packets increases with the number of nodes. To overcome the scalability problem, creating hierarchies among the nodes seems a promising venue and an effective approach to organize the network as the number of nodes increases. In this paper, we investigate the influence of the underlying clustering algorithm on the quality of the routing and illustrate through conducted simulations the gain in network total throughput that can be attained using a clustering scheme that does not rely on periodic exchange of neighborhood information.

Abstract Quality of service (QoS) provisioning generally assumes more than one QoS measure which ... more Abstract Quality of service (QoS) provisioning generally assumes more than one QoS measure which implies that QoS routing can be categorized as an instance of routing subject to multiple constraints: delay-jitter, bandwidth, cost, etc. We study the problem of ...

2014 IEEE International Conference on Communications (ICC), 2014

The number of vehicles on roads keeps increasing continuously, making the management of traffic f... more The number of vehicles on roads keeps increasing continuously, making the management of traffic flow, especially in big cities more and more challenging. One of the key enablers for having smooth traffic flows and better mobility is to rely on real-time traffic monitoring systems. These systems allow road operators to implement intelligent traffic management strategies such as the dynamic adjustment of timing and phasing of traffic lights and the adaptive road congestion charging. Moreover, better informed travelers will plan smartly their journeys and hence potentially contribute in reducing traffic jams. Traditional real-time traffic monitoring usually get real-time data from GPSequipped fleets and fixed sensors installed in specific locations. In this paper, a new real-time traffic monitoring based on emerging vehicular communication systems is proposed. The system enables traffic monitoring with higher reliability, accuracy, and granularity. The cluster-based V2X traffic data collection mechanism is able to gather more than 99% of the available data and reduce the overhead to one quarter when compared to other approaches.

ICT 2013, 2013

ABSTRACT Car to car communication has been getting considerable interest for the last decade, esp... more ABSTRACT Car to car communication has been getting considerable interest for the last decade, especially in the last few years where market introduction phase is approaching fast. A variety of applications will be enabled thanks to car to car communication. Considerable efforts have been already spent in designing and developing efficient broadcast communication systems to support not only safety applications but also infotainment and traffic efficiency applications and services. This leads in less efforts spent on unicast communication solutions that support not only infotainment applications but also traffic efficiency services. To fill this gap, an advanced location service is proposed in this contribution to enable efficient and reliable unicast communications. This solution mixes between short range communication (over 5.9 GHz) and cellular-based communication. The proposed solution has been validated through extensive simulations using a simulation platform which is compliant to latest related standards.

2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2013

ABSTRACT This paper introduces CrossWalk, a novel integrated cross-layer medium access control/ro... more ABSTRACT This paper introduces CrossWalk, a novel integrated cross-layer medium access control/routing protocol based on a receiver-oriented contention resolution mechanism for data dissemination in wireless sensor networks. Traditional approaches for data dissemination such as flooding or simple random walks suffer respectively from a large message forwarding overhead and an excessively long cover time. In this scope, CrossWalk, based on biased random walks, aims to achieve a convenient cover time at the cost of a reasonable overhead. In particular, we demonstrate by an analytical study that the proposed biasing strategy based on a decreasing truncated geometric distribution over a fixed contention window favors a data packet to progress-in a unicast fashion-towards nodes in less explored vicinity by making them more likely to win the contention for the medium access. We therefore show by extensive simulations that CrossWalk outperforms common random walks in terms of partial coverage and efficient network resources consumption by making less redundant message transmissions.

2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2013

ABSTRACT This paper introduces CrossWalk, a novel integrated cross-layer medium access control/ro... more ABSTRACT This paper introduces CrossWalk, a novel integrated cross-layer medium access control/routing protocol based on a receiver-oriented contention resolution mechanism for data dissemination in wireless sensor networks. Traditional approaches for data dissemination such as flooding or simple random walks suffer respectively from a large message forwarding overhead and an excessively long cover time. In this scope, CrossWalk, based on biased random walks, aims to achieve a convenient cover time at the cost of a reasonable overhead. In particular, we demonstrate by an analytical study that the proposed biasing strategy based on a decreasing truncated geometric distribution over a fixed contention window favors a data packet to progress-in a unicast fashion-towards nodes in less explored vicinity by making them more likely to win the contention for the medium access. We therefore show by extensive simulations that CrossWalk outperforms common random walks in terms of partial coverage and efficient network resources consumption by making less redundant message transmissions.

2012 IEEE Vehicular Technology Conference (VTC Fall), 2012

ABSTRACT

Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems - MSWiM '13, 2013

ABSTRACT In recent years, the use of random walks (RW) for data forwarding in wireless sensor net... more ABSTRACT In recent years, the use of random walks (RW) for data forwarding in wireless sensor networks (WSN) has gained a lot of popularity. However, a negative effect is often caused by the fact that a completely uniform random choice of the next hop during the walk translates into a reduced progress towards the sink node, thereby yielding a long latency. Several strategies are proposed to attenuate this problem. Most of them are characterized by their dependence on state information stored in sensor nodes in order to bias the direction of the walk towards the target. Such information require additional capabilities and it is costly in terms of complexity and energy, which is inherently problematical in WSN. This leads to a tradeoff between mutually contradictory goals and raises the question as to what extent biasing RW can affect the performance of the data forwarding scheme. This question is our primary motivation in investigating the problem of biasing RW based data forwarding from a pure analytical perspective.

2013 9th International Wireless Communications and Mobile Computing Conference (IWCMC), 2013

ABSTRACT

2012 IEEE International Conference on RFID-Technologies and Applications (RFID-TA), 2012

ABSTRACT

Nous nous intéressons à l'étude des phénomènes de transfert de chaleur dans un échangeur à calopo... more Nous nous intéressons à l'étude des phénomènes de transfert de chaleur dans un échangeur à caloporteurs fluide et solide, formé de compartiments remplis de fluide et de milieux poreux et dont les frontières horizontales sont soumises à des flux de chaleur non uniforme. Le caloporteur fluide, saturant le milieu poreux, est injecté à une vitesse et une température constantes et dont les particules fluides sont considérées en hors équilibre thermique local avec les particules solides composantes du milieu poreux. Cet écoulement est régi par les équations de conservation de masse et de quantité de mouvement de Darcy-Brinkman et celles de la conservation de l'énergie dans les deux phases fluides et solides. Nous proposons d'analyser leurs effets sur le régime d'écoulement. Les calculs sont effectués pour une seul perméabilité de la grille poreuse (nombre de Darcy Da=10 -4 ), le nombre de Reynolds, Re =10 et un nombre de Rayleigh fixé à Ra=10 4 .

Power conservation techniques are of utmost importance in Wirreless LANs to prolong the life of m... more Power conservation techniques are of utmost importance in Wirreless LANs to prolong the life of mobile stations relying on portable limited enrgy batteries. A power conservation mechanism should provide the maximum energy saving at light traffic loads, yet thrives to deliver data as much as possible in high traffic conditions. In this paper, we investigate the inherent functional properties of the infrastructure mode IEEE 802.11 Power Saving Mechanism (PSM). We show through extensive simulations that PSM stands very short and does not level up to its design objectives. PSM blocks the network traffic flow, yet it does not adequately save energy as supposed to be. We show that at high traffic loads, PSM exhibits a very poor throughput and excessive power consumption per delivered data frame. We therefore investigate the inherent properties that made PSM inefficient and propose two different enhancements called State Aware PSM (SA-PSM) and Once Poll PSM (OP-PSM). We show through extensive simulations that tangible improvements are attained. These enhancements save power as much as PSM for light traffic loads and deliver as much a throughput as when no power saving mechanism is deployed. Virtually at all traffic loads, OP-PSM and SA-PSM nicely outperform PSM and provide a much less average time spent by a data frame from its generation at the source station until its delivery to the destination station.

International Journal of Heat and Mass Transfer

Les transferts coupl es de mati ere et de chaleur par convection naturelle sont etudi es en r egi... more Les transferts coupl es de mati ere et de chaleur par convection naturelle sont etudi es en r egime permanent num eriquement et exp erimentalement au cours de l' evapo-condensation dans une cavit e rectangulaire de rapport g eom etrique 10. Une paroi sur laquelle ruisselle un ®lm d'eau est soumise a une densit e de¯ux de chaleur constante tandis que la paroi parall ele est maintenue a une temp erature basse. L' etude vise de mani ere g en erale a l'am elioration de la distillation dans les syst emes de dessalement solaire. Les equations sont r esolues par une m ethode de volumes ®nis et fournissent les champs de temp erature, concentration et vitesse dans la phase gazeuse pour di erentes densit es du¯ux de chaleur. L' etude par simulation a permis de quanti®er les in¯uences sur le d ebit moyen de distillation de nombreux param etres tels que le¯ux de chauage, la temp erature et le d ebit de l'eau d'alimentation, la temp erature de la paroi de condensation, le facteur de forme de la cellule. Les r esultats exp erimentaux obtenus sur une cellule pilote concernant la production d'eau dessal ee confortent les r esultats de simulation. Pour une densit e de¯ux de chaleur de 1000 W m À2 , un rendement de 0,7 est couramment atteint. Ó 2001 Elsevier Science Ltd. All rights reserved.

Ad-hoc networks have received significant attention over the last few years as these emerging net... more Ad-hoc networks have received significant attention over the last few years as these emerging networks provide a fast deployable multi-hop wireless infrastructure for a growing number of applications when a wireline network is neither available nor economical to build. To overcome the scalability problem, creating hierarchies among the nodes seems to be a promising approach and an effective way to organize the network as the number of nodes increases. In this paper, we present a novel distributed clustering algorithm for ad-hoc networks. Our algorithm is based on a synchronized and layered process. Its main objective is to minimize the number of control messages exchanged during the clustering process.We evaluate our algorithm using the Visidia simulation test bed and show that it outperforms one of the most known clustering algorithms in minimizing both the number of control messages and the number of elected clusterheads.

The intrinsic characteristics of ad hoc networks, such as the frequent connectivity changes and t... more The intrinsic characteristics of ad hoc networks, such as the frequent connectivity changes and the strict bandwidth and power constraints, impose further challenges, especially for routing tasks. Establishing and maintaining routes are hard tasks in a dynamic environment, in particular for large and dense networks where the control overhead induced by routing packets increases with the number of nodes. To overcome the scalability problem, creating hierarchies among the nodes seems a promising venue and an effective approach to organize the network as the number of nodes increases. In this paper, we investigate the influence of the underlying clustering algorithm on the quality of the routing and illustrate through conducted simulations the gain in network total throughput that can be attained using a clustering scheme that does not rely on periodic exchange of neighborhood information.