SATURN D6.5 - Final Report

The objective of the SATURN (Strategic Allocation of Traffic Using Redistribution in the Network) project is to make novel and credible use of market-based demand-management mechanisms to redistribute air traffic in the European airspace. This reduces congestion and saves the airspace users operational costs. The project is motivated by frequent demand and capacity imbalances in the European airspace network, which are forecast to continue in the near future. The present and foreseen ways of dealing with such imbalances mainly concern strategic and tactical capacity-side interventions, such as resectorisation and opening of more sectors to deal with excess demand. These are followed by tactical demand management measures, if needed. As a result, not only do substantial costs arise, but airspace users are also typically left with no choice but to comply with imposed air traffic flow management measures. The project shows how economic signals could be given to airspace users and air navigation service providers (ANSPs) to improve capacity-demand balancing, airspace design and usage, and what the benefits would be of a centralised planner compared with those of decentralised maximisation of self interests (by the ANSPs and/or airspace users)

Reducing ATFM delays through strategic flight planning

This paper presents an integer programming model for strategic redistribution of flights so as to respect nominal sector capacities, in short computation times for large-scale instances. The main contribution lies in the combination of tackling large-scale strategic flight planning using hard capacity constraints, while considering the whole network (i.e., both airports and sectors). Real historic data for network and traffic description are used for our test instance. Strategic and tactical impact assessments show that early flight planning can lead to the reduction of delays and their costs, showing potential for actual implementation

The Impact of Uncertain Departure Delays on Flight Flexibility

The difficulty in synchronizing the activities of different actors and the existence of external constraints, e.g., weather conditions, usually produce some uncertainty on the exact time at which a flight operation can be executed. To cope with this uncertainty, aircraft operators need some flexibility when performing their flight operations, i.e., departing, arriving and flying through air sectors. We express this flexibility in terms of time windows, i.e, periods of time within which flight operations can be executed. The more flexible a flight is, the wider its time windows are. Time windows are centrally calculated and assigned to flights under the agreement that when a flight performs all its operations within the corresponding time windows, no downstream delay is caused to any other actor of the air traffic system. When a flight is unable to respect its time windows, some delay may also be caused to other flights. This paper investigates the effects on the system in terms of additional delay of the nonfulfillment of time windows at flight departures. It considers both airline collaboration and non-collaboration cases and proposes an algorithm that reduces this additional delay. This is achieved through the reassignment of capacity released by flights that are either delayed or have departed. We simulate a set of realistic instances where delays at departure are randomly assigned to flights after time windows have been determined. Our results show that the amount of additional delay generated by departure delays is limited, thus demonstrating the practical viability of the proposed approach

Flexibility in strategic flight planning

A deterministic model that indicates flexibility of flights at the strategic level (up to 6 months ahead) taking into account changing airspace configurations and capacity is formulated. Flexibility is quantified by means of time windows (TWs). Flights complying with TWs guarantee that they will not impact negatively any other flight. Three variants of the model and three types of TWs are tested on a large-size data instance (the European network for an entire day of traffic). The model output specifies the constrained flights (i.e., with TWs shorter than the maximum size allowed for their definition), the constraining sector-hours and provides a list of saturated sector-hours. The meaning of each of the results is explored, across the three TW model variants, as well as the capability of the model variants to assure that capacity limits will not be exceeded. The criticality index, a measure of the sector-hour saturation, is introduced. This index can be used to identify areas for potential improvements. Sharing the information obtained from the TW model results at a strategic level can help both airlines and air navigation service providers (ANSPs) to improve the network status: airlines can decide to re-route heavily constrained flights (e.g., with one minute wide TWs), whereas ANSPs could decide to re-organise the capacity provision of the saturated airspace portions. The TW model can be re-run with the proposed changes, with the goal to assess the impact on both the individual stakeholders and the network. Thus, the model offers the measure of flight flexibility, and can be used as a tool to assess the impact of changes, helping in decision-making processes of airlines and ANSPs

The Air Traffic Flow Management Problem with Time Windows

This paper defines a set of temporal intervals, called time windows, which are defined prior to flight departure and constitute milestones to be met during the flight execution. The size of the time windows is variable as it reflects all known constraints, such as punctuality at destination, runway capacities or congested en-route areas that the flight will cross. Once a time window is defined, all the air traffic actors are committed to guarantee that flight operations, e.g. enter an airspace sector, depart from or arrive at an airport, are executed within the time window. We propose a two-step approach based on a mixed integer programming formulation. The first step determines a set of time windows such that the overall cost of delay is minimized. Then in the second step we choose the set of optimal time windows which also maximizes the overall time window size. In such a way, we provide to all air traffic stakeholders the largest degree of flexibility to perform their operations under the constraint that the minimum achievable delay is kept constant. We also gain information on the critical flights of the system: if the optimal width of a time window is equal to its minimum available value, any disruption that may cause the flight not to meet it may produce undesired downstream effects. Our preliminary computational experience based on small-scale random instances confirms that the flexibility granted to flights increases with the capacity while the system delay simultaneously decreases. We also show that when there is no congestion a non negligible share of small size time windows may exist, thus indicating the existence of bottlenecks and critical flights

An excursion in reaction systems : from computer science to biology

Reaction systems are a formal model based on the regulation mechanisms of facilitation and inhibition between biochemical reactions, which underlie the functioning of living cells. The aim of this paper is to explore the expressive power of reaction systems as a modeling framework, showing how their basic assumptions and properties can be exploited to formalize computer science and biology oriented problems. In this view, we first provide a reaction-based description of an iterative algorithm to solve the Tower of Hanoi puzzle. Then, we show how the regulation of gene expression in the lac operon, involved in the metabolism of lactose in Escherichia coli cells, can be formalized in terms of reaction systems. Finally, we present a method to derive, given a reaction system with n reactions, a functionally equivalent system with n\u2032 64n reactions using simplification methods of boolean expressions. Some final remarks and directions for future research conclude the paper

SATURN D1.2 - Data Management (update report)

Motivated by frequent demand and capacity imbalances in the European airspace network, the SATURN project (‘Strategic Allocation of Traffic Using Redistribution in the Network’) is examining realistic ways to use market-based demand-management mechanisms to redistribute air traffic. Building upon the earlier data management report, this document provides an update of data management activities that run throughout the project

SATURN D2.1 - Future airspace congestion - a users' discussion guide

The objective of SATURN is to propose and test realistic ways to use market-based, demand-management mechanisms to redistribute air traffic in the European airspace. This document presents a review of the literature on mechanisms, current policy goals, instruments available for their application, and possible future policy goals, from the point of view of their impact on the project. It also includes a review of passenger fare elasticities. We introduce a number of pricing scenarios and candidate mechanisms for capacity redistribution. These will be reviewed by stakeholders at a dedicated workshop. The workshop design and processes are described

SATURN D3.1 - Pricing mechanisms

Motivated by frequent demand and capacity imbalances in the European airspace network, the SATURN project (‘Strategic Allocation of Traffic Using Redistribution in the Network’) is examining realistic ways to use market-based demand-management mechanisms to redistribute air traffic. Building upon previous deliverables this document presents the set of strategic pricing mechanisms for demand-capacity balancing. Four research avenues were pursued, branching into five centralised and two decentralised pricing mechanisms presented. A comprehensive assessment framework is introduced which will facilitate the demonstration of the validity of designed mechanisms

Enhancing Reaction Systems: A Process Algebraic Approach

In the area of Natural Computing, reaction systems are a qualitative abstraction inspired by the functioning of living cells, suitable to model the main mechanisms of biochemical reactions. This model has already been applied and extended successfully to various areas of research. Reaction systems interact with the environment represented by the context, and pose problems of implementation, as it is a new computation model. In this paper we consider the link-calculus, which allows to model multiparty interaction in concurrent systems, and show that it allows to embed reaction systems, by representing the behaviour of each entity and preserving faithfully their features. We show the correctness and completeness of our embedding. We illustrate our framework by showing how to embed a lac operon regulatory network. Finally, our framework can contribute to increase the expressiveness of reaction systems, by exploiting the interaction among different reaction systems