Madani Bezoui

D-LPCN: A Distributed Least Polar-angle Connected Node Algorithm for Finding the Boundary of a Wireless Sensor Network

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.

Detecting gaps and voids in WSNs and IoT networks: the minimum x-coordinate based method

When we deal with the deployment structure of Wireless Sensor Networks (WSNs) used in applications where the zone-of-interest is not accessible by humans, like forest fire detection, military applications, etc., random deployment is often the main or even the only practical solution that can be chosen. One of the main issues in this deployment is that it can lead to a formation of gaps or voids, which represent non-covered zones in the network. This can be very problematic, since it is not possible to detect some serious and dangerous problems, like a starting fire, the presence of non-desired persons or cyber-security attacks, etc. Therefore, detecting non-covered zones is of high importance. In this paper, we present a new method that allows to detect gaps and voids in WSNs and IoT networks after executing the D-LPCN algorithm and using some characteristics related to the value of the angle formed by the node of the gap having the minimum x-coordinate.1

A distributed security protocol designed for the context of internet of things

In the field of Internet of Things (IoT), many encryption protocols for distributed wireless communication technology have been proposed for use in various applications such as monitoring, healthcare, product management, workplace, home support and surveillance [1]. An IoT system can be looked at as a highly dynamic distributed and networked system composed of a large number of smart devices. In fact, such connected devices suffer from the limitation of resources in terms of computing, energy, bandwidth and storage. Hence, IoT application scenarios require methods to adapt to highly diverse contexts with different available resources and possibly dynamic environments. In this paper, we address these issues by proposing an efficient technique for data protection in the context of IoT. A distributed network architecture is used, where each node is in charge to deliver and/or forward data. The aim is to use efficient operations to protect the exchanged data. The proposed technique ensures the exchanged data to be effectively and securely controlled with a low overhead compared to the classical approaches. The proposed protocol shows its efficiency in terms of overhead, speed, energy and security measurements.

Detecting gaps and voids in WSNs and IoT networks: the angle-based method

A random deployment of Wireless Sensor Networks (WSNs) is often the basic structure used in the context of fire forest detection, military applications or any situation where the zone-of-interest is not accessible by humans. The main problematic in this kind of deployment is the formation of gaps or voids, which represent a zone which is not covered in the network. This reduces significantly its Quality of Service and can lead to serious problems, like a non-detected starting fire, the presence of unexpected persons or attacks, etc. Therefore, detecting zones that are not covered by the WSN is of great importance. In this paper, we present a new method allowing to detect gaps and voids in WSNs or in IoT networks by using some characteristics of the angles of the polygon formed by the boundary as determined by the D-LPCN algorithm. These angles can be interior or exterior. Characterizing the angles of the polygon formed by these boundary nodes allows to specify whether this boundary is a gap or a void, in case where the obtained polygon is interior. Since D-LPCN is fault-tolerant, the simulation results show that it is possible to use it for the detection of faulty nodes and intrusions.1

LOGO: A New Distributed Leader Election Algorithm in WSNs with Low Energy Consumption

The Leader Election Algorithm is used to select a specific node in distributed systems. In the case of Wireless Sensor Networks, this node can be the one having the maximum energy, the one situated on the extreme left in a given area or the one having the maximum identifier. A node situated on the extreme left, for instance, can be used to find the boundary nodes of a network embedded in the plane. The classical algorithm allowing to find 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 may be subject to an important number of collisions and lost messages. In this paper, we propose a new algorithm called LOGO (Local Optima to Global Optimum) where some local leaders will send a message to a given node, which will designate the global leader. This process is more reliable since broadcast messages are sent only twice by each node, and the other communications are based on a direct sending. The obtained results show that the proposed algorithm reduces the energy consumption with rates that can exceed 95% compared with the classical Minimum Finding Algorithm.