1,720,980 research outputs found
Air Robust Routes: analysis of the direct costs
No full textAirline costs, as well as airspace safety, are deeply influenced by congestion in the air traffic network. Congestion are due to the limited capacity of the control points (airports or fixed points) of the network, that is bounded by a maximum number of aircraft that can fly on them in the same time interval. Control points capacity can change real time due to unforeseen events, such as weather condition changes. Its reduction usually implies real time managing operations that consist either in rerouting the aircraft, with respect to the nominal shortest route, or in postponing departures: in any case additional costs are implied. Instead of the shortest route, we propose to assign to each flight the shortest robust route, that for each network point has a valid alternative route that allows the aircraft to reach the destination within a certain known time limit. In this paper we give the definition of the robust routes and the main implementation details. We also make a preliminary analysis of the direct costs of the robust routes with respect to the shortest ones
Airport Ground Movement Problem: Minimization of Delay and Pollution Emission
No full textIn this paper, we deal with the problem of routing and scheduling aircraft ground movement operations. We implement two objective functions: the minimization of total routing taxiing delay and the minimization of pollution emission in terms of total waiting time the engines are turned on. We use alternative graph model to represent the routing solution and to solve the airport ground movement problem. We consider the case study of malpensa terminal maneuvering area, Italy, which implies a peculiar traffic flow management due to its complex layout, where runways and taxi network intersect in many points. Experimental results based on real data are reported, which are promising both for the total routing taxiing delay minimization and the reduction of the pollution emission
A Lagrangian Relaxation Method for an Online Decentralized Assignment of Electric Vehicles to Charging Stations
No full textA model to optimize the airport terminal departure operations
No full textThe rapid increase in passenger traffic on the one hand and the slow expansion of airport capacity on the other have over the years limited the airport's capability to maintain satisfactory service to the customer. The main objectives of airport operators are the cost effectiveness and the customer satisfaction. These two indicators are related to the first two phases of an airport terminal departure operations that involve the check-in controls and the security controls. This paper proposes an optimization model that, given a certain layout and a passengers flow, decides the number of check-in desks and security control checkpoints to minimize a cost function. The cost function considers the costs of check-in and security control checkpoints and an estimate of the passenger dissatisfaction. The model develops an optimization algorithm that integrates a simulation module. The optimization algorithm is based on the surrogate method that minimizes the cost function that does not have a closed-form expression. To this reason, the simulation module reproduces the real scenario of the terminal operations and the passengers behaviour and calculates the value of the cost function. Tests have been conducted considering the real case study of Napoli-Capodichino (IT) airport
Rerouting algorithms solving the air traffic congestion
No full textCongestion in the air traffic network is a problem with an increasing relevance for airlines costs as well as airspace safety. One of the major issue is the limited operative capacity of the air network. In this work an Autonomous Agent approach is proposed to solve in real time the problem of air traffic congestion. The air traffic infrastructures are modeled with a graph and are considered partitioned in different sectors. Each sector has its own decision agent dealing with the air traffic control involved in it. Each agent sector imposes a real time aircraft scheduling to respect both delay and capacity constrains. When a congestion is predicted, a new aircraft scheduling is computed. Congestion is solved when the capacity constrains are satisfied once again. This can be done by delaying on ground aircraft or/and rerouting aircraft and/or postponing the congestion. We have tested two different algorithms that calculate K feasible paths for each aircraft involved in the congestion. Some results are reported on North Italian air space
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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