Tarek Moulahi

Securing data exchange in wireless multimedia sensor networks: perspectives and challenges

The emerging use of Wireless Multimedia Sensor Networks (WMSNs) and communication facilities have increased the need for network security measures to protect different types of multimedia data either real time or non-real time during the transmission period. A lot of researchers are becoming more interested on secure WMSNs due to the broad application necessities which can be range over smart environment, security surveillance and smart health-care; so requirements on secure aggregation of multimedia data, Quality of Service (QoS) and privacy should be satisfied. Current technologies vs. proposed security techniques in WMSNs and its pros and cons from a security point of view are explored in details. In addition to promising future trends of this research area by giving more attention for new challenging problems including secure routing protocol, fault tolerant, robustness and recovery process. We believe that this paper will add significantly a valuable discussion among the researchers and promote them to fetch new research ideas to design approximately best model by combining the most important security issues in order to reach secure WMSNs.

Review: Broadcasting based on dominated connecting sets with MPR in a realistic environment for WSNs & ad hoc

Broadcasting in wireless sensor networks (WSNs) is the dissemination of packets from one node to all nodes in the network. This flooding causes redundant data and broadcast storm problems. To counteract this effect, many methods have been introduced to minimize the redundancy, such as MPR (MultiPoint Relay) or DS-MPR (Connected Dominating Sets with MPR). These methods stipulate that a packet is correctly received if the receiver node is in the transmission radius of the sender node. But this fact is not always true, due to many factors like signal attenuation, noise and existence of obstacles. This paper focuses on DS-MPR. Firstly, we test it in a realistic environment to show its limit in terms of reachability. Secondly, we introduce a modification of DS-MPR to be applicable with a realistic physical layer. Our heuristic method is called RDS-MPR (Realistic DS-MPR). This heuristic has improved DS-MPR in reachability, which may exceed more than 94%. Finally, we introduce an extension of RDS-MPR, called eRDS-MPR (extended RDS-MPR) which provides a reachability of up to more than 97%.

Enhancing digital image integrity by exploiting JPEG bitstream attributes

Abstract The need for protecting a huge amount of digital images on the internet has become an important requirement against different kind of attacks in order to insure transmitted process in a secure way. Cryptography introduces many security goals to achieve privacy of image include confidentiality, authentication and integrity. Encryption process may applied on the result of JPEG DCT-based encoding process, which are DC and AC coefficients, where DC coefficients present the average of the overall magnitude of the input image and AC coefficients present the higher frequency components of image. In this paper, we develop a new model for securing the transmitted images via wireless network by parsing JPEG bitstream to encrypting both DC and AC coefficients in each 8×8 block of image. This work utilizes the features of DCT-based encoding process preserving low complexity, efficient compression, and robustness to protect the image integrity. The experiments result shows that the proposed approach gives an interesting and a significant robustness ratio reaching a range of 60.3 dB for Peak Signal-to-Noise Ratio (PSNR) and a 0.006% for Bit Error Rate (BER) in average. The obtained results are discussed in details.

A survey and comparative study of QoS aware broadcasting techniques in VANET

Vehicular ad hoc networks are a special type of MANET providing vehicle to vehicle and vehicle to roadside wireless communications. Vehicular ad-hoc network (VANET) have been designed in order to assist drivers on the road with a variety of applications especially in preventing danger and saving lives. For such ends, broadcasting is a suitable scheme to convey emergency messages dissemination to the entire network. Broadcasting in VANETs is a challenging task due to the specific VANET features such as nodes mobility and frequent topology changes. VANET applications, especially those related with human life saving, are delay sensitive and have specific requirements in terms of performances and QoS. A QoS aware broadcasting scheme relies on different factors and has to deal with hard constraints. In this paper, we introduce a survey of broadcasting in vehicular networks and discussion of different performance and QoS related to broadcasting issues. Furthermore, a comparative study of QoS aware broadcasting protocols classifying them according to different taxonomies is elaborated. This survey specifies QoS requirements and performance metrics of VANET services. Furthermore, this survey focuses on QoS aware broadcasting as a challenging problem regrading VANET characteristics.

Reliable relay-based broadcasting through formal concept analysis for WSNs

Broadcasting is a fundamental operation in wireless sensor networks and is used for querying, key distribution, time synchronization, routing, and node localization. Nevertheless, sensors are prone to failures such as software or hardware malfunctioning, exhaustion of energy, and environmental hazards. In this paper, a review of realistic dominated connected set with multipoint relay RDS-MPR is performed. Then, an enhancement of this method, called reliable relay-based broadcasting RRB, is proposed. RRB improves RDS-MPR by considering a trusted index for each node, which is updated during the data gathering process at the sink node. In addition, the use of formal concept analysis in RRB provides the best sorting of nodes according to their weights, which helps to refine selection of relay nodes compared with RDS-MPR. The effectiveness of the proposed scheme is measured through a simulation study using NS-2. Copyright

Fault-tolerant flooding through formal concept analysis for wireless sensor networks

Flooding and broadcasting are basic and fundamental operations in Wireless Sensor Networks (WSNs). In fact, they are used for data dissemination, time synchronization, key distribution, node localization, and routing. On the other hand, sensors are prone to failure such as exhaustion of energy, environmental hazards, and software or hardware malfunctioning. In this paper, we make an enhancement of the latest proposed relay-based broadcasting method by considering a trust index model to achieve a fault tolerant relay node selection. In addition, Formal Concept Analysis is used instead of the linear function. The effectiveness of the proposed scheme is confirmed through a simulation study using NS-2.

Authenticating Sensitive Speech-Recitation in Distance-Learning Applications using Real-Time Audio Watermarking

Thispaper focuses on audio-watermarking authentication and integrity-protection within the context of the speech-data transmitted over the Internet in a real-time learning environment.The Arabic Quran recitation through distance learning is used as a case-study example that is characteristic of sensitive data requiring robust authentication and integrity measures. Thisworkproposes an approach for the purpose ofauthenticating and validatingaudio-data transmitted by a publisher or during communications between an instructor and students reciting via Internet communications.The watermarking approach proposed here is based on detection of the key patternswithin the audio signal as an input to the algorithm before the embedding phase is performed.The developed application could be easily used at both sides of the communication for ensuring authenticity and integrity of the transmitted speech signal and is proved effective for many distance-learning applications that require low-complexity processing in real-time

Effect of selective replication strategy and dynamic admission control to QoS management in video on demand systems

Abstract Several solutions have been proposed till date to achieve effective replication policies and admission control methods that can ensure a high Quality of Service (QoS) to Video on Demand (VoD) systems. In this paper, we have chosen to study admission control and a replication strategy in a video on demand system called Feedback Control Architecture for Distributed Multimedia Systems (FCA-DMS). The proposed approaches are founded on (i) the supervision and auto-adaptation of the system load, (ii) continued knowledge of the network and of the video servers’ workload, and (iii) the development of a dynamic replication strategy of segments for popular video, that remade to replica-placement problem by discussing the problem of the replicas number to create (Replication Degree). The workload of video servers and of network are calculated by a QoS controller. The proposed approach takes into account of replica detail and offers a replica removal policy to avoid waste and for a good management of storage space. The goal is to maintain an updated broad view of the system’s behaviour from the collected measurements to databases of available videos and databases of available video servers. To demonstrate the efficiency and feasibility of our approaches and validate the results obtained, we conducted a series of experiments based on a simulator that we implemented.

Fault-Tolerant Energy-Efficient Tree in Dynamic WSNs

Broadcasting has a main importance in Wireless Sensor Networks (WSNs). Effectively, the sink node has to collect periodically, data from the environment supervised by sensors. To perform this operation, it sends requests to all nodes. Furthermore, WSNs have a dynamic behaviour due to their evolution. At any time, a node can be retrieved from the network due to an exhausting energy or a node problem. In fact, WSNs are prone to failure such as software or hardware malfunctioning, exhaustion of energy, wireless interference and environmental hazards. Thus, an appropriate broadcasting method should take into consideration this aspect and uses the less possible amount of energy to accomplish the task. In this paper, a robust tree-based scheme is proposed which is called Robust Tree Broadcasting (RTB). The new scheme has a load-balanced behaviour which induces an efficient use of energy. In addition, RTB has a high-quality fault tolerant performance.