Samira Moussaoui

Data Replication in Mobile Ad Hoc Networks

Data replication is suitable to improve the response time, the global traffic, and the sharing of data since even in the case of disconnection of a server. The nodes can continue to have access to replicas of data. On an Ad hoc mobile network, the frequent partition of the network and the lack of fixed infrastructures complicate the data access and the sharing task.

Disaster Management Projects Using Wireless Sensor Networks: An Overview

There are numerous projects dealing with disaster management and emergency response that use wireless sensor networks technologies. Indeed, WSNs offer a good alternative compared to traditional ad hoc networks. Air pollution monitoring, forest fire detection, landslide detection, natural disaster prevention, industrial sense and control applications, dangerous gas leakage, water level monitoring, vibration detection to prevent an earthquake, radiation monitoring are examples of the WSN applications related to disaster management. This paper presents an overview of the recent projects using WSN to collect data in disaster areas.

GMAC: Group mobility adaptive clustering scheme for Mobile Wireless Sensor Networks

Recently, with the emergence of MWSNs utilization in different applications, some real-world situations, such as large-scale military networks and search-and-rescue operations, consider that sensor nodes move together in groups. To approximate the simulation of such applications to the reality, group mobility models are required. In this paper, we propose a group mobility adaptive clustering scheme (GMAC) for mobile WSN based on a new group mobility metric Mobility Group, which use network topology information and a position predictor to determine if nodes move together or separately. In GMAC, the area of interest is divided in equal zones, and each sensor calculates its weight based on Mobility Group and residual energy. The sensor node with the greatest weight in its zone will become the cluster-head. Using RPGM mobility model we have performed simulations to illustrate the benefits of our proposal comparing to ACE-L and LEACH. Obtained results show that GMAC outperforms ACE-L and LEACH in terms of energy consumption and the amount of data packets received at the sink.

A Survey on Pseudonym Changing Strategies for Vehicular Ad-Hoc Networks

The initial phase of the deployment of vehicular ad-hoc networks (VANETs) has begun and many research challenges still need to be addressed. Location privacy continues to be in the top of these challenges. Indeed, both academia and industry agreed to apply the pseudonym changing approach as a solution to protect the location privacy of VANETs’ users. However, due to the pseudonyms linking attack, a simple changing of pseudonym shown to be inefficient to provide the required protection. For this reason, many pseudonym changing strategies have been suggested to provide an effective pseudonym changing. Unfortunately, the development of an effective pseudonym changing strategy for VANETs is still an open issue. In this paper, we present a comprehensive survey and classification of pseudonym changing strategies. We then discuss and compare them with respect to some relevant criteria. Finally, we highlight some current researches, and open issues and give some future directions.

An overview of localization algorithms in mobile wireless sensor networks

Localization problem in mobile wireless sensor networks has drawn widely attention in recent years due to the rapid advances in mobile computing and improvements of wireless communication technologies. Indeed, mobile sensor networks become a valuable asset for many applications, since sensors can be mobile or easily tethered to mobile entities such as robots, vehicles or human. Thereby, it is crucial to support mobility without compromising the quality of applications that require wireless communications. Although, numerous research activities have successfully addressed the localization problem in static networks, few studies deal with the localization issue in mobile sensor networks. In this paper, we present a survey on existing work in this area and we address the gaps for actual deployment of mobile wireless sensor networks. Following our analysis, we propose a classification of the most important algorithms and schemes that outcome from recent literature. We discuss their basic principles, characteristics and concepts. Finally, we point out open research issues, their challenges and some future directions for localization in mobile wireless sensor networks.

Data Dissemination and Power Management in Wireless Sensor Networks

Data dissemination in wireless sensor networks has been considered as an important mechanism and very interested issue. In such environment, data dissemination is generally performed from sensor nodes to the sink. Thus, each sensor node can be implicitly provided the direction to forward sensing data towards the sink. The inherent characteristics of sensor nodes such as limited battery and limited computing capability, make the forwarding mechanism is not more suitable for this kind of network. In this paper, we present new data dissemination protocol based energy-efficient called Data Dissemination and Power Management Protocol (DDPM). In this protocol, we propose new energy management scheme using a dynamic power threshold. Firstly, in the initialization phase, the sensor nodes organized under clusters and cluster head should be selected for each cluster. Secondly, in the data dissemination phase, the cluster head collects and transmits the sensing data based on the data dissemination process. The simulation result shows that the proposal protocol permits to reduce the energy consumption and prolong the network life.

Urban pseudonym changing strategy for location privacy in VANETs

The development of an effective pseudonym changing strategy to protect the location privacy of the vehicular adhoc networks VANETs users is still an open problem in the literature. In this paper, we first propose a comparison between the existing pseudonym changing strategies. This comparison is based on their effectiveness to prevent the pseudonyms linking attacks and based on the costs involved in changing a pseudonym. We also propose a new pseudonym changing strategy adapted for the urban environment, called urban pseudonym changing strategy UPCS. UPCS is based on the construction of silent mix zones SMs at signalised intersections. UPCS can be configured to use either pseudonyms changing technique or pseudonyms exchanging technique inside these SMs. The analyses show a good level of prevention against the pseudonyms linking attacks. The performances are evaluated in various vehicular scenarios. The obtained results show high levels of location privacy protection can be achieved using UPCS with pseudonyms changing configuration.

An SDMA-Based Mechanism for Accurate and Efficient Neighborhood-Discovery Link-Layer Service

Neighborhood-discovery link-layer service is provided by beaconing, which denotes the process of periodically broadcasting status information. It allows vehicles to be aware of their surroundings. The availability of neighborhood knowledge guarantees accurate estimation of safety-related situations and helps to make strategic decisions based on assumed fresh information. Beacon messages share the same channel (control channel, CCH) as safety messages and are sent with no schedule; this may lead to severe contention and packet loss, which can be dramatic for safety applications. The main goal of this paper is to provide a method to synchronize beacons sending in a distributed manner so that all nodes proceed to their sending within a beacon session that takes place in one CCH interval (CCHI). Simulation results demonstrate the feasibility of the method and provide a high level of accuracy and efficiency compared with the standard.

Mobile sink and power management for efficient data dissemination in wireless sensor networks

Data dissemination in wireless sensor networks is the main goal and the final waited objective of the sensor network deployment. In such environment which consists of a large number of low cost devices, sensor nodes generate sensed data of stimulus and forward them to sinks via wireless multi-hops communication. In typical wireless sensor network, the sensor nodes are equipped with irreplaceable batteries and characterized by limited computing capability. Therefore, minimizing the energy consumption of the sensor nodes and thus maximizing the lifetime of sensor networks is one of the most important research issues. In this paper, we present new data dissemination protocol based energy-efficient called energy-based data dissemination protocol. In this protocol, we propose new energy management scheme using a dynamic power threshold and we introduce also new sink mobility scheme to balance the network load between sensor nodes and thus improve the performances. Firstly, in the initialization phase, the sensor nodes organized under clusters and cluster head should be selected for each cluster. Secondly, in the data dissemination phase, the cluster head collects and transmits the sensed data based on the data dissemination process. In this phase, sensor sink may move toward any cluster based on its sensed data frequency to minimize energy consumption of sensor nodes near the fixed sinks due to relaying of large amount of data. The simulation result shows that the proposal protocol permits to reduce the energy consumption and prolong the network life.

An agent based Rumor Dissemination for routing in Wireless Sensor Networks

The main problem for Wireless Sensor Networks deployed in environments with no geographical localization system is the uniform distribution of information in the network. For that purpose we propose a new routing protocol based on an Efficient Rumor Dissemination called: Fast Rumor Routing. The FRA protocol optimizes the agent (respectively the query) propagation through the network preventing backward paths. The rumor succeeds to reach far regions in the network in a trajectory as straight as possible, reducing the total overhead of the network. Furthermore, for important and critique data in a real time applications, FRA with replicas (FRA_R) was implemented and tested to ensure a good delivery rate of the query in a short delays and prevent by this way the problem of path deficiency. Simulation results show that the main contributions of FRA protocol are the reduction of: time of path establishment, the overhead caused in the network and consequently the energy consumption.