Farid Lalem

Bio: Farid Lalem is an academic researcher from University of Western Brittany. The author has contributed to research in topics: Wireless sensor network & Key distribution in wireless sensor networks. The author has an hindex of 8, co-authored 18 publications receiving 156 citations. Previous affiliations of Farid Lalem include Centre national de la recherche scientifique.

A distributed multi-path routing algorithm to balance energy consumption in wireless sensor networks

Abstract: A large use of applications of Wireless Sensor Networks (WSNs) pushes researchers to design and improve protocols and algorithms against the encountered challenges. One of the main goals is data gathering and routing to the base station (through the sink nodes) with lack of acknowledgement and where each node has no information about the network. Unbalanced energy consumption during the data routing process is an inherent problem in WSNs due to the limited energy capacity of the sensor nodes. In fact, WSNs require load balancing algorithms that make judicious use of the limited energy resource to route the gathered data to the sink node. In this paper, we propose a balanced multi-path routing algorithm by focusing on the residual energy and the hop count of each node to discover the best routes and to insert them into the routing table. The main idea of this algorithm comes from Ant Colony Optimization (ACO) and automata network modelization. Hence, the potential performance of the proposed algorithm relies on the best route to be selected which should have the minimum number of hops, the maximum energy and weighted energy between participating nodes to extend the lifetime of the network.

D-LPCN: A distributed least polar-angle connected node algorithm for finding the boundary of a wireless sensor network

Abstract: A boundary of wireless sensor networks (WSNs) can be used in many fields, for example, to monitor a frontier or a secure place of strategic sensitive sites like oil fields or frontiers of a country. This situation is modeled as the problem of finding a polygon hull in a connected Euclidean graph, which represents a minimal set of connected boundary nodes. In this paper we propose a new algorithm called D-LPCN (Distributed Least Polar-angle Connected Node) which represents the distributed version of the LPCN algorithm introduced in [1]. In each iteration, any boundary node, except the first one, chooses its nearest polar angle node among its neighbors with respect to the node found in the previous iteration. The first starting node can be automatically determined using the Minimum Finding algorithm, which has two main advantages. The first one is that the algorithm works with any type of a connected network, given as planar or not. Furthermore, it takes into account any blocking situation and contains the necessary elements to avoid them. The second advantage is that the algorithm can determine all the boundaries of the different connected parts of the network. The proposed algorithm is validated using the CupCarbon, Tossim and Contiki simulators. It has also been implemented using real sensor nodes based on the TelosB and Arduino/XBee platforms. We have estimated the energy consumption of each node and we have found that the consumption of the network depends on the number of the boundary nodes and their neighbors. The simulation results show that the proposed algorithm is less energy consuming than the existing algorithms and its distributed version is less energy consuming than the centralized version.

BROGO: A New Low Energy Consumption Algorithm for Leader Election in WSNs

Abstract: The Leader Election in Wireless Sensor Networks depends on the nature of the application domain, the use case and the energy consumption In the case of real time applications, the choice will be based on the speed of the election, and in the case where time is not important, the choice will be based on the energy consumption The classical algorithm allowing to elect such a node is called the Minimum Finding Algorithm In this algorithm, each node sends its value in a broadcast mode each time a better value is received This process is very energy consuming and not reliable since it is subject to an important number of collisions and lost messages In this paper, we propose a new algorithm called BROGO (Branch Optima to Global Optimum) where after finding a spanning tree of a WSN, each leaf will route a message through its branch to the root in order to find the leader in that branch The root will then elect the global leader from the received branch leaders This process is more reliable since there is a small number of broadcast messages and a reduced number of nodes that send broadcast messages at the same time The obtained results show that the proposed algorithm reduces the energy consumption with rates that can exceed 95% when compared with the classical Minimum Finding Algorithm Its message and time complexity is equal to O(n)

A self-managing volatile key scheme for wireless sensor networks

Abstract: The last decade has seen major advances in Wireless Sensor Networks (WSN). The limited amount of resources in WSNs is the main challenge for securing them. Indeed, sensors are inherently small devices with limited embedded storage, processor and battery capacity. The situation is even worse when attackers, with virtually unlimited amount of resources, have direct physical access to sensors. Cryptographic keys are used for authentication, authorization, confidentiality, data integrity, as well as many other security services. Several proposals have been made for key management in WSNs. In this paper, we review some notable key management schemes and propose a new one. The originality of our work lies in two main facts: first, we do not place a master key on all sensors before deploying them as several other proposals did, but we rather place the master key in a subset of sensors; second, the master keys are volatile, i.e., sensors use the master key to bootstrap the system and they delete them shortly after that. Our extensive simulations have shown the efficiency of our approach.

A wait-before-starting algorithm for fast, fault-tolerant and low energy leader election in WSNs dedicated to smart-cities and IoT

Abstract: Many of the existing Leader Election algorithms don't deal with energy consumption and fault tolerance since they are not mainly dedicated to autonomous systems like wireless sensor and IoT networks. It is possible to use the classical Minimum Finding (MinFind) algorithm, where each node sends its value in a broadcast mode each time a better value is received. This process is very energy consuming and not realistic since it may be subject to an important number of collisions. In this paper, we propose a new algorithm called WBS (Wait-BeforeStarting), which is fault tolerant and where each node in the network will wait for a certain time before starting the execution of its program. This time lapse depends on the node's value so that the leader will be the one which will wait the least. In this case, the leader will be the first one which will start by sending a message to all the nodes of the network to inform them that it is the leader. Then, the other nodes will start the execution of their programs. Otherwise, if the leader fails, another node will do the same. The obtained results show that the proposed algorithm reduces the energy consumption with rates that can exceed 96% compared with the classical MinFind Algorithm.

Nonce-based symmetric encryption

Abstract: Symmetric encryption schemes are usually formalized so as to make the encryption operation a probabilistic or state-dependent function e of the message M and the key K: the user supplies M and K and the encryption process does the rest, flipping coins or modifying internal state in order to produce a ciphertext C. Here we investigate an alternative syntax for an encryption scheme, where the encryption process e is a deterministic function that surfaces an initialization vector (IV). The user supplies a message M, key K, and initialization vector N, getting back the (one and only) associated ciphertext C = e N K(M). We concentrate on the case where the IV is guaranteed to be a nonce-something that takes on a new value with every message one encrypts. We explore definitions, constructions, and properties for nonce-based encryption. Symmetric encryption with a surfaced IV more directly captures real-word constructions like CBC mode, and encryption schemes constructed to be secure under nonce-based security notions may be less prone to misuse.

Parametric Loop Division for 3D Localization in Wireless Sensor Networks.

Abstract: Localization in Wireless Sensor Networks (WSNs) has been an active topic for more than two decades. A variety of algorithms were proposed to improve the localization accuracy. However, they are either limited to two-dimensional (2D) space, or require specific sensor deployment for proper operations. In this paper, we proposed a three-dimensional (3D) localization scheme for WSNs based on the well-known parametric Loop division (PLD) algorithm. The proposed scheme localizes a sensor node in a region bounded by a network of anchor nodes. By iteratively shrinking that region towards its center point, the proposed scheme provides better localization accuracy as compared to existing schemes. Furthermore, it is cost-effective and independent of environmental irregularity. We provide an analytical framework for the proposed scheme and find its lower bound accuracy. Simulation results shows that the proposed algorithm provides an average localization accuracy of 0.89 m with a standard deviation of 1.2 m.

Optimal Energy Resources Allocation Method of Wireless Sensor Networks for Intelligent Railway Systems.

Abstract: The rapid increase of train speed has brought greater challenges to the safety and reliability of railway systems. Therefore, it is necessary to monitor the operation status of trains, infrastructure, and their operating environment in real time. Because the operation environment of railway systems is complex, the construction cost of wired monitoring systems is high, and it is difficult to achieve full coverage in the operation area of harsh environments, so wireless sensor networks are suitable for the status monitoring of railway systems. Energy resources of nodes are the basis of ensuring the lifecycle of wireless sensor networks, but severely restrict the sustainability of wireless sensor networks. A construction method of special wireless sensor networks for railway status monitoring, and an optimal energy resources allocation method of wireless sensor networks for intelligent railway systems are proposed in this paper. Through cluster head selection and rotating probability model, clustering generation and optimization model, and partial coverage model, the energy consumption of nodes can be minimized and balanced. The result of simulation experiment proved that the lifetime of wireless sensor networks can be maximized by the optimal energy resources allocation method based on clustering optimization and partial coverage model, based on polynomial time algorithm.