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Item A critical review of quality of service models in mobile ad hoc networks(Inderscience Enterprises Ltd, 2019) Bouchama, Nadir; Aïssani, Djamil; Djellab, Natalia; Nouali-Taboudjemat, NadiaQuality of service (QoS) provisioning in mobile ad hoc networks (MANETs) consists of providing a complex functionality in a harsh environment where resources are scarce. Thus, it is very challenging to build an efficient solution to address this issue. The proposed solutions in the literature are broadly classified into four categories, namely: QoS routing protocols, QoS signalling, QoS-aware MAC protocols and QoS models, which are the main concern of our study. The contribution of this paper is threefold: Firstly, we propose a set of guidelines to deal with the challenges facing QoS models design in ad hoc networks. Secondly, we propose a new taxonomy for QoS models in ad hoc networks. Finally, we provide an in-depth survey and discussion of the most relevant proposed frameworks.Item Lifetime-Aware Backpressure : A New Delay-Enhanced Backpressure-Based Routing Protocol(IEEE, 2019-03) Kabou, Abdelbaset; Nouali-Taboudjemat, Nadia; Djahel, Soufiene; Yahiaoui, Saïd; Nouali, OmarDynamic backpressure is a highly desirable family of routing protocols known for their attractive mathematical properties. However, these protocols suffer from a high end-to-end delay making them inefficient for real-time traffic with strict end-to-end delay requirements. In this paper, we address this issue by proposing a new adjustable and fully distributed backpressure-based scheme with low queue management complexity, named Lifetime-Aware Backpressure (LTA-BP). The novelty in the proposed scheme consists in introducing the urgency level as a new metric for service differentiation among the competing traffic flows in the network. Our scheme not just significantly improves the quality of service provided for real-time traffic with stringent end-to-end delay constraints, but interestingly protects also the flows with softer delay requirements from being totally starved. The proposed scheme has been evaluated and compared against other state-of-the-art routing protocol, using computer simulation, and the obtained results show its superiority in terms of the achieved end-to-end delay and throughput.Item Reachability in big graphs : A distributed indexing and querying approach(Elsevier, 2021-09) Hocine, Imane; Yahiaoui, Saïd; Bendjoudi, Ahcene; Nouali-Taboudjemat, NadiaThe advent of Big graphs characterized by their enormous number of nodes, with multiple edges between them makes the existing reachability query indexing approaches unable to guarantee a reasonable time for both the index construction and query steps. Therefore a novel approach that takes into account these new characteristics during the graph processing is needed. In this paper, we propose an Overlay Graph-based Distributed Reachability Indexing approach (ODRI), an indexing scheme through which the index construction and reachability query are processed in a parallel and distributed manner. The key idea of ODRI is to process a Big graph as a set of smaller subgraphs (partitions) interconnected to each other through an overlay graph. In this way, the partitions can be indexed in parallel and, at the same time, the reachability information can also be extracted. Hence, the index construction and query processing time will be reduced significantly. Therefore, ODRI ensures the scalability of Big graphs, which is a challenge for the existing reachability approaches. Besides, we formally prove that this strategy preserves the reachability properties. Using real-life data, we experimentally verify that our approach outperforms the state-of-the-art methods, and is scalable in terms of the number of partitions, regardless of how graphs are distributed.Item A Survey on Distributed Graph Pattern Matching in Massive Graphs(ACM, 2021-02) Bouhenni, Sarra; Yahiaoui, Saïd; Nouali-Taboudjemat, Nadia; Kheddouci, HamamacheBesides its NP-completeness, the strict constraints of subgraph isomorphism are making it impractical for graph pattern matching (GPM) in the context of big data. As a result, relaxed GPM models have emerged as they yield interesting results in a polynomial time. However, massive graphs generated by mostly social networks require a distributed storing and processing of the data over multiple machines, thus, requiring GPM to be revised by adopting new paradigms of big graphs processing, e.g., Think-Like-A-Vertex and its derivatives. This article discusses and proposes a classification of distributed GPM approaches with a narrow focus on the relaxed models.Item Distributed graph pattern matching via bounded dual simulation(Elsevier, 2022-09) Bouhenni, Sarra; Yahiaoui, Saïd; Nouali-Taboudjemat, Nadia; Kheddouci, HamamacheGraph Pattern Matching (GPM) finds subgraphs of a large data graph that are similar to an input query graph. It has many applications, such as pattern recognition, detecting plagiarism, and finding communities in social networks. Current real-world applications generate massive amounts of data that cannot be stored on the memory of a single machine, which raises the need for distributed storage and processing. Recent relaxed GPM models, although of polynomial time complexity, are nevertheless not distributed by nature. Moreover, the existing relaxed GPM algorithms are limited in terms of scalability. In this paper, we propose Bounded Dual Simulation (BDSim) as a new relaxed model for a scalable evaluation of GPM in massive graphs. BDSim captures more semantic similarities compared to graph simulation, dual simulation, and even strong simulation. It preserves the vertices’ proximity by eliminating cycles of unbounded length from the resulting match graph. Furthermore, we propose distributed vertex-centric algorithms to evaluate BDSim. We prove their effectiveness and efficiency through detailed theoretical validation and extensive experiments conducted on real-world and synthetic datasets. To the best of our knowledge, BDSim is the first relaxed GPM model that captures the cyclic structure of the query graph while being feasible in cubic time.Item Multi-objective offline and online path planning for UAVs under dynamic urban environment(2022-03) Sadallah, Nassim; Yahiaoui, Saïd; Bendjoudi, Ahcene; Nouali-Taboudjemat, NadiaThis paper presents a multi-objective hybrid path planning method MOHPP for unmanned aerial vehicles (UAVs) in urban dynamic environments. Several works have been proposed to find optimal or near-optimal paths for UAVs. However, most of them did not consider multiple decision criteria and/or dynamic obstacles. In this paper, we propose a multi-objective offline/online path planning method to compute an optimal collision-free path in dynamic urban environment, where two objectives are considered: the safety level and the travel time. First, we construct two models of obstacles; static and dynamic. The static obstacles model is based on Fast Marching Square (FM2) method to deal with the uncertainty of the geography map, and the unexpected dynamic obstacles model is constructed using the perception range and the safety distance of the UAV. Then, we develope a jointly offline and online search mechanism to retrieve the optimal path. The offline search is applied to find an optimal path vis-a-vis the static obstacles, while the online search is applied to quickly avoid unexpected dynamic obstacles. Several experiments have been performed to prove the efficiency of the proposed method. In addition, a Pareto front is extracted to be used as a tool for decision making.Item Efficient parallel edge-centric approach for relaxed graph pattern matching(Springer, 2022-02) Bouhenni, Sarra; Yahiaoui, Saïd; Nouali-Taboudjemat, NadiaPrior algorithms on graph simulation for distributed graphs are not scalable enough as they exhibit heavy message passing. Moreover, they are dependent on the graph partitioning quality that can be a bottleneck due to the natural skew present in real-world data. As a result, their degree of parallelism becomes limited. In this paper, we propose an efficient parallel edge-centric approach for distributed graph pattern matching. We design a novel distributed data structure called ST that allows a fine-grain parallelism, and hence guarantees linear scalability. Based on ST, we develop a parallel graph simulation algorithm called PGSim. Furthermore, we propose PDSim, an edge-centric algorithm that efficiently evaluates dual simulation in parallel. PDSim combines ST and PGSim in a Split-and-Combine approach to accelerate the computation stages. We prove the effectiveness and efficiency of these propositions through theoretical guarantees and extensive experiments on massive graphs. The achieved results confirm that our approach outperforms existing algorithms by more than an order of magnitude.Item Toward a new Backpressure-based framework to Enhance Situational Awareness in Disaster Response(IEEE ICT-DM-2017, 2017-12-11) Kabou, Abdelbaset; Nouali-Taboudjemat, Nadia; Nouali, OmarCrises generate intense need to communication not just as a panic reaction to crisis, but also due the critical need for communication in order to better coordinate during response activities. In the afterward of a disaster, the lack of resources to handle this increase of data, due to the fragility of network infrastructures, leads to network congestion or overload. The results is that critical data are prevented from reaching decision makers, which has a direct impact on situational-awareness. To overcome this problem, we propose a new cross layer architecture for Wireless Mesh Network with a twofold objective: one, to include a filtering system able to identify the most critical data and two, to propose a routing layer with the capacity to prioritize these data while ensuring the stability and throughput optimality of the whole network. The proposed solution combines both by proposing an adjustable and fully distributed version of the high throughput efficient Backpressure routing protocol, with a geolocation and role-based filtering and prioritizing system. Both components collaborate in a way to identify and send most critical data, using a lower end-to-end delay, without however starving less critical data. Extensive experiments, using NS-3 simulator, are used to validate the proposal and confirm the high impact of the introduced ideasItem New GPU-based Swarm Intelligence Approach For Reducing Big Association Rules Space(CERIST, 2017-06-14) Djenouri, Youcef; Bendjoudi, Ahcène; Djenouri, Djamel; Belhadi, Asma; Nouali-Taboudjemat, NadiaThis paper deals with exploration and mining of association rules in big data, with the big challenge of increasing computation time. We propose a new approach based on meta-rules discovery that gives to the user the summary of the rules’ space through a meta-rules representation. This allows the user to decide about the rules to take and prune. We also adapt a pruning strategy of our previous work to keep only the representatives rules. As the meta-rules space is much larger than the rules space, two approaches are proposed for efficient exploitation. The first one uses a bees swarm optimization method in the meta-rules discovery process, which is extended using GPU-based parallel programming to form the second one. The sequential version has been first tested using medium rules set, and the results show clear improvement in terms of the number of returned meta-rules. The two versions have then been compared on large scale rules sets, and the results illustrate the acceleration on the summarization process by the parallel approach without reducing the quality of resulted meta-rules. Further experiments on Webdocs big data instances reveal that the proposed method of pruning rules by summarizing meta-rules considerably reduces the association rules space compared to state-of-the-art association rules mining-based approaches.Item Installation et configuration d’une solution de détection d’intrusions sans fil (Kismet)(CERIST, 2011-06) Lounis, Karim; Babakhouya, Abdelaziz; Nouali-Taboudjemat, NadiaLes réseaux sans fil (Wi-Fi, norme 802.11) offrent plusieurs avantages ; notamment en terme de mobilité, coût, débit et facilité de déploiement. Cependant, ils sont par nature plus sensibles aux problèmes de sécurité. Les mécanismes de sécurité (WEP, WPA, WPA2) ne permettent pas de se prévenir contre tous les problèmes de sécurité. En effet, les bornes Wi-Fi restent toujours vulnérables aux intrusions : attaque de déni de service, rogue AP, attaque de dé-authentification. Dans cette optique, il est conseillé de surveiller régulièrement l'activité du point d'accès sans fil afin de détecter les activités anormales sur le réseau et de les signaler sous forme d’ALERTES. Ce rapport présent les détails techniques d’installation et de configuration d’une solution de détection d’intrusion pour un réseau Wi-Fi. Cette solution se base sur des logiciels open source (Linux, Kismet, OPENWRT, DD-WRT, SWATCH) et une série de matériels sans fil (routeur Linksys WRT54GL et carte réseau sans fil).