Network-wide assessment of 4D trajectory adjustments using an agent-based model

This paper presents results from the SESAR ER3 Domino project. It focuses on an ECAC-wide assessment of two 4D-adjustment mechanisms, implemented separately and conjointly. These reflect flight behaviour en-route and at-gate, optimising given (cost) objective functions. New metrics designed to capture network effects are used to analyse the results of a microscopic, agent based model. The results show that some implementations of the mechanisms allow the protection of the network from ‘domino’ effects. Airlines focusing on costs may trigger additional side-effects on passengers, displaying, in some instances, clear trade-offs between passenger- and flight-centric metrics

Evolution of Binary Black Hole Spacetimes

We describe early success in the evolution of binary black hole spacetimes with a numerical code based on a generalization of harmonic coordinates. Indications are that with sufficient resolution this scheme is capable of evolving binary systems for enough time to extract information about the orbit, merger and gravitational waves emitted during the event. As an example we show results from the evolution of a binary composed of two equal mass, non-spinning black holes, through a single plunge-orbit, merger and ring down. The resultant black hole is estimated to be a Kerr black hole with angular momentum parameter a~0.70. At present, lack of resolution far from the binary prevents an accurate estimate of the energy emitted, though a rough calculation suggests on the order of 5% of the initial rest mass of the system is radiated as gravitational waves during the final orbit and ringdown.Comment: 4 pages, 3 figure

Testing a Simplified Version of Einstein's Equations for Numerical Relativity

Solving dynamical problems in general relativity requires the full machinery of numerical relativity. Wilson has proposed a simpler but approximate scheme for systems near equilibrium, like binary neutron stars. We test the scheme on isolated, rapidly rotating, relativistic stars. Since these objects are in equilibrium, it is crucial that the approximation work well if we are to believe its predictions for more complicated systems like binaries. Our results are very encouraging.Comment: 9 pages (RevTeX 3.0 with 6 uuencoded figures), CRSR-107

Alternatives to standard puncture initial data for binary black hole evolution

Standard puncture initial data have been widely used for numerical binary black hole evolutions despite their shortcomings, most notably the inherent lack of gravitational radiation at the initial time that is later followed by a burst of spurious radiation. We study the evolution of three alternative initial data schemes. Two of the three alternatives are based on post-Newtonian expansions that contain realistic gravitational waves. The first scheme is based on a second-order post-Newtonian expansion in Arnowitt, Deser, and Misner transverse-traceless (ADMTT) gauge that has been resummed to approach standard puncture data at the black holes. The second scheme is based on asymptotic matching of the 4-metrics of two tidally perturbed Schwarzschild solutions to a first-order post-Newtonian expansion in ADMTT gauge away from the black holes. The final alternative is obtained through asymptotic matching of the 4-metrics of two tidally perturbed Schwarzschild solutions to a second-order post-Newtonian expansion in harmonic gauge away from the black holes. When evolved, the second scheme fails to produce quasicircular orbits (and instead leads to a nearly head-on collision). This failure can be traced back to inaccuracies in the extrinsic curvature due to low order matching. More encouraging is that the latter two alternatives lead to quasicircular orbits and show gravitational radiation from the onset of the evolution, as well as a reduction of spurious radiation. Current deficiencies compared to standard punctures data include more eccentric trajectories during the inspiral and larger constraint violations, since the alternative data sets are only approximate solutions of Einstein's equations. The eccentricity problem can be ameliorated by adjusting the initial momentum parameters.Comment: 11 pages, 11 figures, 1 appendix, typos corrected, removed duplicate reference, matches published versio

The Clustering of Organizational Innovation: Developing Governance Models for Vertical Integration

This case explores a cluster of firms that emerged sharing a particular ownership structure. Typically, clusters are thought of as interrelated firms that produce similar products and services. However, we document the emergence and evolution of a cluster of entrepreneurial ventures that developed using a unique governance structure. We explore the deviant case of Renville, MN because of its notable success in developing a series of entrepreneurial ventures that provided producers with the opportunity to vertically integrate.collective entrepreneurship, organizational innovation, joint vertical innovation, cluster, Agribusiness, Research and Development/Tech Change/Emerging Technologies, Q10, Q13, Q16,

Pilot3 crew multi-criteria decision support tool estimating performance indicators and uncertainty

When a flight’s operational conditions change (e.g., an updated weather forecast), various alternative trajectories may be computed. These usually require trade-offs between expected fuel burn and delay. The pilot, or the dispatcher, considers these expected values to decide how to operate the flight. This approach has two main challenges. Firstly, it requires the translation of arrival delay into parameters that are relevant for the airline (on-time performance and cost of delay). Secondly, uncertainties in the system need to be estimated (e.g., holding at arrival). These estimations rely on airline staff expertise. Pilot3 sets out to overcome these issues by developing a new, multi-criteria decision-support tool, which incorporates explicit estimators for performance indicators and ATM operational parameters. These estimators will be developed incrementally, from simple heuristics to advanced machine-learning models, building on previous experience

Engage D5.14 Engage SESAR Summer School 2021

This report describes the third edition of the Engage SESAR summer school, which was held as a virtual event, between 30th August and 2nd September 2021

Vista D1.2 - Final Project Results Report

Vista assesses primary trade-offs in ATM between key performance areas in the current and future timeframes, including how they are affected by SESAR and non-SESAR factors. The project has examined the effects of market forces (e.g. fuel prices, economic development), technologies and regulatory factors on European performance in ATM, through the evaluation of stakeholder and environmental indicators. The approaches selected for the various layers in the model are described, and the corresponding results of each are presented. The strategic layer implements an agent-based economic model and a schedule mapper to generate demand and capacity for the different stakeholders, flight schedules and passenger flows – it feeds the pre-tactical layer. The pre-tactical layer transforms the output of the strategic layer into individual flight plans, passenger itineraries and ATFM regulations delay – it feeds the tactical layer. The tactical layer runs the day of operations, tracking flights and passengers and reacting to the tactical situation in the system. Trade-offs have been assessed and visualised within and between periods, and between stakeholders. The Final Project Results Report provides a summary of the entire project, from objectives to main conclusions. Lessons learned and recommendations for future research and development activities are reported along with a self-assessment of the project’s maturity