This paper presents a new approach for merging multiple aircraft flows in a Terminal Maneuvering Area (TMA). This work is motivated by the current overloaded airspace near large airports and the need of more efficient methods to help controllers. Some attempts to alleviate airspace congestion such as the minimum spacing requirements, negotiation of voluntary reductions in scheduled service, and the construction of additional runways at major airports have been done. Even though, more fundamental changes are needed to improve the use of available air capacity. Present research consists of a new approach to optimize a set of aircraft planned to land at a given airport; it is proposed to merge the incoming flows from different routes by mean of speed and path changes. Due to the high combinatoric induced by such a problem, a stochastic optimization algorithm has been developed in order to propose to each aircraft a new route and speed profile. Those changes aim to remove conflicts at merging points and to maintain separation of aircraft following the same route link according to their wake turbulence constraint. The optimization criteria is based on the minimum deviation from the initial path planning. This algorithm has been successfully applied to Gran Canaria airport in Spain with real traffic demand samples for which conflict free flow merging is produced smoothly with optimal runway feeding.
This paper presents a new challenging modelling approach to support different heuristics to tackle the pallet loading problem (PLP). A discrete event system model to tackle the PLP is specified using the coloured Petri net formalism in order to integrate the model with the industrial context in which the PLP must be solved. New events can be formalised in the model to implement different heuristics to consider the upstream (production) and downstream (transport) influence of the palletising activity in the logistic flow. A state space analysis is performed to evaluate the different solutions to fit the maximum number of boxes on a rectangular pallet, supporting the inherent box diversity (heterogeneous palletising problems) of present production and distribution logistic systems. The heuristics implemented show that acceptable occupancy results can be obtained without requiring the exhaustive evaluation of the different feasible combination. The results demonstrate that it outperforms other approaches which have been suggested for this type of problem. Potentially useful extensions of the work are discussed.
The current overloaded airspace near large airports leads the stakeholders to develop more fundamental means to improve the use of available air capacity in dense traffic areas as terminal maneuvering area. A smart planning of aircraft trajectories and an appropriate designing of route structure can be a solution. Therefore, to analyze the capability of them, this paper proposes a novel approach to deal with the merging and sequencing problem of arrival traffic in terminal maneuvering area, and examines the performance of diverse conflict resolution strategies and different terminal maneuvering area route structure. An evolutionary algorithm is employed to resolve potential conflicts, altering one or more of the following decision variables: routes, speeds, and entrance time to terminal maneuvering area (slot). Two different fitness functions were developed. One aims to minimize potential conflicts and the other one aims to minimize at the same time potential conflicts and delay induced at runway. The performance of different combinations of decision variables, or conflict resolution strategies, is evaluated through a set of arrival aircraft to Grand Canaria airport. Also, four different route structures are tested by using the same set of incoming aircraft. The results showed that the slot and speed change and mix of all change strategies can successfully resolve all conflicts in an efficient manner. The results also suggested that topologies with one main merging point are more efficient than the ones that have two merging points. Finally, a significant abatement of delay was observed when minimizing conflicts and delay while achieving conflict-free solutions.
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