No abstract

The presence of obstructing obstacles severely degrades the efficiency of routing protocols in MANETs. To mitigate the effect of these obstructing obstacles, routing in MANETs is usually based on the a priori knowledge of the obstacle map. In this paper, we investigate rather the dynamic and autonomic detection of obstacles that might stand within the network. This is accomplished using the enhanced cartography optimized link state routing CE-OLSR with no extra signaling overhead. The evaluation of the performance of our proposed detection scheme is accomplished through extensive simulations using OMNET++. Results clearly show the ability of our proposed scheme to accurately delimit the obstacle area with high coverage and efficient precision ratios. Furthermore, we integrated the proposed scheme into CE-OLSR to make it capable of autonomously detecting and avoiding obstacles. Simulation results show the effectiveness of such an integrated protocol that provides the same route validity as that of CE-OLSR-OA which is based on the a priori knowledge of the obstructing obstacle map.

No abstract

The need for increasing air traffic capacity motivates 4D trajectory planning concept. In order to generate conflict-free 4D trajectories, we introduce a new concept based on light propagation modeling algorithm. This algorithm is a wavefront propagation method that yields a natural solution for the path planning problem specifically in the case of air traffic congestion.

The North Atlantic oceanic airspace is considered the most congested oceanic airspace in the world. For many years, air traffic control in this airspace has experienced difficulties due to the limited radar coverage. To support conflictfree flight progress, a structure of routes, called Organized Track System, is established in the North Atlantic airspace and very restrictive separation standards are applied. The development of the Automated Dependent Surveillance-Broadcast system provides an opportunity to improve the flight planning operations over the oceans by reducing separation norms. The aim of this study is to improve the traffic efficiency in the North Atlantic airspace by developing new approaches to organize the transatlantic traffic at the strategic level. The first considered approach proposes a new route structure, referred to as Wind-Optimal Track Network, to replace the Organized Track System, while the second one is based on Wind-Optimal Free Routes. The problem is modeled as an optimization problem and resolved further via Simulated Annealing combined with Sliding Window algorithm. Results of simulations performed on the real traffic data prove that about 76% of flights decreased their cruising times by more than half an hour when flying wind-optimal tracks rather than using their great circle routes from the departure to the destination. Furthermore, by comparing the two proposed methods we conclude that Wind-Optimal Free Routes implies lower cruising times, while the Wind-Optimal Track Network is much more robust under changing wind fields.