Slimane Bah

Petri net extension for traffic road modelling

Traffic flow modelling is an essential step for designing and controlling the transportation systems. It is not only necessary for improving safety and transportation efficiency, but also it can yield economic and environmental benefits. Consider the discrete and continuous aspects of traffic flow dynamics, hybrid Petri nets have proved to be a powerful tool for approaching this dynamics and describe the vehicle behavior accurately since they include both aspects. A new extension of hybrid petri net is presented in this paper for generalizing the traffic flow modelling through taking into account state dependencies on external rules which can be timed and also nondeterministic time such as stop sign or priority roads. Moreover, a segmentation of roads is proposed to deal with the accurate localization of events.

Extended Batches Petri Nets Based System for Road Traffic Management in WSNs

One of the most critical issues in modern cities is transportation management. Issues that are encountered in this regard, such as traffic congestion, high accidents rates and air pollution etc., have pushed the use of Intelligent Transportation System (ITS) technologies in order to facilitate the traffic management. Seen in this perspective, this paper brings forward a road traffic management system based on wireless sensor networks; it introduces the functional and deployment architecture of the system and focuses on the analysis component that uses a new extension of batches Petri nets for modeling road traffic flow. A real world implementation of visualization and data analysis components were carried out.

Dynamic clustering algorithm based on beacon delay

Vehicular Ad-Hoc Network, or VANET is a computerized system which provides communications for a group of vehicles between each other and with equipments installed on the road side (RSU) or with camera mounted on the traffic light poles or, even with sophisticated sensors. In this paper we propose a new model of cluster formation based on beacon delay for real scenarios in VANET. Our approach is fully distributed. In fact, the main weakness of some of the existing solutions is their dependence on central units namely RSUs, making these solutions static and expensive to deploy. Therefore, the objective of this work is to propose a more adapted solution to dynamic environments such as VANET. The main idea is to make central vehicle acting like RSU. We call this central vehicle cluster head surrounded by a set of vehicles selected carefully to form a cluster. We propose a new clustering mechanism based on beacon delay.

A New Cluster-Based Paradigm for SIP Routing in MANET

We propose a new paradigm based on a time varying grid to handle SIP routing over MANET. This paradigm takes advantage of the geometric properties of the square grid in order to establish calls using the closest route to the callee in terms of physical distance. Normally, shorter paths and optimized latencies are reached by broadcast based approaches where bindings of the whole network are stored in every single node and where SIP REGISTER messages are flooded. Our approach utilizes a grid based clustering method to arrange MANET nodes in an organized structure during the initialization phase in order to mark the centroid of each cluster. Then, the structure is updated periodically using the initial coordinates of the centroids. We resort also in this work to the use of replication in an astute manner in order to sidestep to the need of flooding based solutions.

A benchmark for spatial and temporal correlation based data prediction in wireless sensor networks

Missing data is an inevitable problem in wireless sensor network and the way missing values are handled can significantly affect the analysis results involving such data. To address data missing issues, spatial correlation and temporal correlation modeling can be applied. This paper aims at reviewing some popular spatial and temporal correlation based methods. The proposed review includes a critical overview through a summary of pros and cons of these methods and a comparison between them based on simulation results. To our best knowledge, there is no such comparative benchmarking study in the current literature.

Analysis of the Impact of Cognitive Vehicular Network Environment on Spectrum Sensing

The Cognitive Vehicular Network (CVN) has emerged as a promising solution providing additional resources and allowing spectrum efficiency. However, vehicular networks are highly challenging for spectrum sensing due to speed, mobility and dynamic topology. Furthermore, these parameters depend on the CVNs’ environment such as highway, urban or suburban. Therefore, solutions targeting CVNs should take into consideration these characteristics. As a first step towards an appropriate spectrum sensing solution for CVNs, we first, provide a comprehensive classification of existing spectrum sensing techniques for CVNs. Second, we discuss, for each class, the impact of the vehicular environment effects such as traffic density, speed and fading on the spectrum sensing and data fusion techniques. Finally we derive a set of requirements for CVN’s spectrum sensing that takes into consideration specific characteristics of CVN environments.

Multi-hop Clustering Solution Based on Beacon Delay for Vehicular Ad-Hoc Networks

Vehicular ad hoc networks (VANET) are a specific type of networks, wherein nodes are vehicles equipped with wireless receivers. The vehicles can exchange data by using wireless communication either in ad-hoc mode or infrastructure mode through equipments installed on the road side. In vehicular networks, clustering is one of the main dissemination methods, as it enhances the communication reliability and performance. However, a good clustering solution for VANETs has to address the highly dynamic and complex aspects (e.g. real time) of such environments. Of this fact, we propose a novel multi-hop clustering model including: cluster construction/destruction mechanism, multi-hop links establishment and cluster head election algorithm based on a new metric. Indeed, the proposed metric captures real environment parameters. The simulation results show that our clustering solution performs better than existing solutions especially when the obstacle shadowing model is used which is the most likely scenario in real situations.

Event traffic detection using heterogenous wireless sensors network

Deaths due to traffic accidents is a major problem in several countries principally because of the fact that emergency actions are not provided at the place of accident at required time, Basically, in the event of a road accident, a real time traffic accident detection system can intelligently inform the site of accident, reporting it to the proper authorities, informing about the number of injured people so that the type and the amount of emergency services needed can be provided. This paper aims to introduce an approach to the traffic event detection, especially in highways, by the means of heterogeneous WSNs (using unmanned aerial vehicles called UAVs, vehicular sensors, smartphones and ground WSNs). The work includes a system overview and the proposed event detection approach.

Improving CSMA/CA network performance under hidden collision

Dynamic spectrum access policy allows a secondary user (SU) to access a primary user (PU) channel when it is idle. However, the idle state may result from the PUs silent activities, which can be wrongly perceived as an opportunity for the SU to access the channel and lead to “hidden collision” when it effectively tries to access the channel under this condition. At best of our knowledge, this issue has yet to be addressed in the literature. In this paper, we will first define a three-state model that describes hidden collision conditions, then propose a probabilistic model in which a transient state is added to force the SU to wait a certain period of time before accessing the channel, thereby translating into better protection for the PU. Based on this model and using Carrier Sense Multiple Access/Collision Avoidance protocol, we will evaluate the PUs and SUs throughput and delay with and without transient state as well as the gain in using our approach. Our computation results show a substantial improvement of the PUs throughput from 19.6 to 61.1%.

Overview of event detection and surveillance approaches in heterogeneous WSNs

Event detection and surveillance in heterogeneous wireless multimedia sensor network have drawn the interest of several researchers and the use of unnamed vehicles have made it realistic to enhance sensing, processing and communication capabilities in this area. Unnamed vehicles can communicate with different sensors and transfer video streaming data information to the base station or other entities. It can be used for various application areas. Besides, different optimizations criteria must be taken into consideration to achieve main goals. This paper provides an overview of different event and surveillance approaches using heterogeneous sensors and discuss some of their limitations. A comparison criteria are highlighted and discussed to contribute to finding and optimal approach.