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Introduction to rebound effects: A 3-hour workshop
No full textLicenceThis document was designed to facilitate a workshop on "rebound effects". It was developed based on the PhD research work of Laetitia Bornes titled "systemic and concrete methods and tools to address environmental complexity and rebound effects within a design or decision-making process" in collaboration with Lucas Riondet. This workshop is composed of :- a theoretical part (1.5 hours): this part introduces the systemic design and consequential approach and details a definition for rebound effects. In addition, a systemic modelling method and associated tools are presented to support the analysis and anticipation in design of rebound effects. - a practical part (1.5 hours): this part is an application of the tools, presented in the theoretical part, to a case study. The practical part implies therefore to download supplementary material, the "Archetypes cards", available here on https://lii.enac.fr/projects/rebound-archetypes-cards/.Further information on research about rebound effects: https://laetitia-bornes.notion.site/Attendee profile: Students, PhD students, professionals or citizens
Flight Allocation in Flight-centric Air Traffic Control: Hierarchical Clustering and Simulated Annealing Approach
No full textInternational audienceThis study explores flight allocation within a flightcentric air traffic management framework using hierarchical clustering and Simulated Annealing. The proposed approach involves merging interacting flights before balancing the controllers' workload with Simulated Annealing. An analysis of the impact of the grouping threshold is conducted to identify the value that best balances minimizing interactions between flights assigned to different controllers and the controllers' workload. Finally, a comparison with a MILP model demonstrates that the new approach is more computationally efficient and more realistic from an operational perspective.</div
Combustion Dynamics of a Liquid Rocket Engine in subcritical Injection Conditions
No full textInternational audienceIn throttlable liquid rocket engines using methane and oxygen as propellants, the combustion chamber pressure is expected to vary from subcritical to supercritical with respect to the thermophysical state of the propellants during operation of the engine. The aim of the present work is to investigate the influence that thermodynamic injection conditions could have on combustion stability. A numerical framework based on a multi-fluid approach suitable to simulate both sub-and supercritical pressure flows is used. The research combustor BKN from DLR Institute of Space Propulsion is selected as the experimental test case of the current study. In particular, one unstable supercritical load point and two subcritical load points -one stable and one unstable -are selected. The two unstable cases are obtained through instability triggering. The simulated stable case shows good agreement with the experimental flame structure and the chamber pressure. The unstable cases reproduce the non-linear nature of the experimentally observed instabilities, however they slightly overestimate chamber pressure and oscillation amplitudes. Good agreement is found with the first longitudinal modes' frequencies in all cases. The present work demonstrates the capability of investigating combustion instabilities in liquid rocket engines both for two-phase flow and for supercritical injection conditions, opening the path to a series of investigations on the associated flow physics
GenQA: A Method for Generating and Validating Question/Answer Pairs from Journalistic Data Material
No full textInternational audienceData visualizations are now commonly used in online press articles which often supports engaging data-driven stories.However, due to its visual nature, this type of content inherently lacks accessibility (e.g. when one wants to consume those visualizationsusing conversational agents, hearing them in audible formats, or using screen reader). Writing alternative texts is the recommendedstandard in order to provide text descriptions associated with an image. However, newsrooms rarely produce them for data-visualizations,or when they do, these are overly simplistic. Several intertwined limitations explain that situation like the limited amount of timejournalists have to produce these expected detailed descriptions or the lack of precise and standardized writing guidelines for describingvisualizations. To address this issue, we propose a new approach to help journalists generate descriptions of visualizations, basedon a set of generated question and answer pairs (hereafter referred to as Q/A). Due to the previously enumerated limitations, ourmethod first generates those Q/As using a generative AI model of Natural Language Processing (NLP). This approach alleviates andhomogenizes the writing task workload and allows for a systematic and more exhaustive exploration of the possible Q/As for a givenvisualization. However, among the critical challenges of using AI-based generative tools in a journalism context is the risk of publishingunreliable or biased information. Therefore, the methodology proposed in this paper gives the journalist user a high level of control overthe AI-generated Q/As. To enable and optimize this mandatory validation task, we design an interface where Q/As are grouped in termsof semantic and textual content, and accessibility interest. Visual cues are also displayed to improve the journalist’s decision-making.To evaluate this proposed methodology, that we call GenQA, we conducted a comparative design study that gathered journalists fromtwo different Canadian newsrooms and teachers. We observed that GenQA was efficiently used by those users and helped them toproduce detailed visualization descriptions that met their expectations in terms of quality and workload. This study also showed thatGenQA triggered significant serendipity potential, allowing users to explore and produce Q/As that cover aspects they might not haveconsidered
3D Printable Inhomogeneous Dielectric Resonator Antenna with Cardioid Shaped Pattern
No full textInternational audienceThis paper presents the design and simulation of rectangular dielectric resonator antennas (DRAs) that radiate linear polarization with a cardioid-shaped pattern at 2.45 GHz, without the use of a ground plane. The antenna structure allows the balanced excitation of TE and quasi- TM modes by coaxial probe feeding, resulting in orthogonal electric and magnetic dipo-lar contributions. Material inhomogeneity is introduced within the scope of additive manufactory possibilities, by the means of separate regions with homogeneous permittivity, in order to control resonant frequencies and quality factors of modes in spectral proximity. The proposed DRAs are numerically analyzed with eigenmode and far-field simulations using Ansys HFSS. The inhomogeneous DRA achieves a maximum gain of 5.2 dBi at the operating frequency and a 5% operational bandwidth (OBW)
Supporting Adaptive Supervision and Control of Airport Ground Operation
No full textInternational audienceAir traffic control (ATC) relies on both human operators and automation to ensure safety and efficiency. As air traffic grows, automation is increasingly adopted. However, fully automating airport ground operations, aircraft movement between parking areas and runways, remains unfeasible due to the unpredictability of ground traffic, including aircraft delays, sick passengers or weather disruptions. In this paper, we investigate strategies to support dynamic levels of automation, introducing interfaces that enhance supervision through a domain specific graphical language and explicit automation level representations. We also introduce automation-and human-generated cross-checks to monitor critical situations and propose interaction concepts to adjust the level of automation. We conclude with future directions for enabling human operators' interventions with high levels of automation and implications for Human-AI teaming in ATC
EuterPen: Unleashing Creative Expression in Music Score Writing
No full textInternational audienceMusic notation programs force composers to follow the many rules of the staff notation when writing music and constantly seek to optimize symbol placement, making numerous adjustments automatically. Even though this impedes their creative process, many composers still use them throughout their workflow, for lack of a better option. We introduce EuterPen, a music notation program prototype that selectively relaxes both syntactic and structural constraints while editing a score. Composers can input and manipulate music symbols with increased flexibility, leveraging the affordances of pen and touch. They can make space on, between and around staves to insert additional content such as digital ink, pictures and audio samples. We describe the iterative design process that led to EuterPen: prototyping phases, a participatory design workshop, and a series of interviews. Feedback from the participating professional composers indicates that EuterPen offers a compelling and promising approach to music writing
Evaluating the Synergy of Conflict Detection and Resolution Services for Constrained Urban Airspace
No full textInternational audienceVery-low-level (VLL) urban air operations have been extensively investigated as a solution for mitigating congestion in cities. However, the manner in which the management of such traffic should be performed is still actively investigated. One important component of such a system is the conflict detection and resolution (CD&R), mainly composed of the strategic and tactical CD&R module. While many approaches towards these have been studied, insufficient analysis has been conducted on their compatibility when functioning within a unified, hybrid system. Additionally, their robustness to operational uncertainties such as wind and departure delays is often overlooked. In this work, we investigate the performance of strategic planing methods when combined with tactical CD&R and subjected to a wide range of traffic demand levels and uncertainty conditions. Simulations indicate that the performance of the strategic deconfliction module is highly sensitive to the presence of wind and delay. This decline in performance is partially mitigated by the tactical deconfliction module. Thus, the results suggest that increased use of tactical CD&R could lessen the required level of detail of strategic deconfliction methods, leading to improved compatibility between the two modules.</div
Integrating Realistic 3d Aircraft Trajectory Optimization with Climate Impact Metrics for Sustainable Aviation
No full textA pseudo-random and non-point Nelson-style process
No full textWe take up the idea of Nelson’s stochastic processes, the aim of which was to deduce Schrödinger’s equation. We make two major changes here. The first one is to consider deterministic processes which are pseudo-random but which have the same characteristics as Nelson’s stochastic processes. The second is to consider an extended particle and to represent it by a set of interacting vibrating points. In a first step, we represent the particle and its evolution by four points that define the structure of a small elastic string that vibrates, alternating at each period a creative process followed by a process of annihilation. We then show how Heisenberg’s spin and relations of uncertainty emerge from this extended particle. In a second step, we show how a complex action associated with this extended particle verifies, from a generalized least action principle, a complex second-order Hamilton-Jacobi equation. We then deduce that the wave function, accepting this complex action as a phase, is the solution to a Schrödinger equation and that the center of gravity of this extended particle follows the trajectories of de Broglie-Bohm’s interpretation. This extended particle model is built on two new mathematical concepts that we have introduced: complex analytical mechanics on functions with complex values and periodic deterministic processes. In conclusion, we show that this particle model and its associated wave function are compatible with the quantum mechanical interpretation of the double-scale theory we recently proposed.Nous reprenons l’idée des processus stochastiques de Nelson, dont le but était de déduire l’équation de Schrödinger. Nous apportons ici deux changements majeurs. Le premier est de considérer des processus déterministes pseudo-aléatoires mais qui ont les mêmes caractéristiques que les processus stochastiques de Nelson. Le second est de considérer une particule étendue et de la représenter par un ensemble de points vibrants en interaction. Dans un premier temps, nous représentons la particule et son évolution par quatre points qui ont la structure d’une petite corde élastique qui vibre en alternant à chaque période un processus de création suivi d’un processus d’annihilation. Nous montrons ensuite comment le spin et les relations d’incertitude d’Heisenberg émergent de cette particule étendue. Dans un deuxième temps, nous montrons comment une action complexe associée à cette particule étendue vérifie, à partir d’un principe de moindre action généralisé, une équation de Hamilton-Jacobi complexe du second ordre. Nous déduisons ensuite que la fonction d’onde, acceptant cette action complexe comme phase, est la solution d’une équation de Schrödinger et que le centre de gravité de cette particule étendue suit les trajectoires de l’onde pilote de de Broglie-Bohm. Ce modèle de particule étendue est construit sur deux nouveaux concepts que nous avons introduit : une mécanique analytique complexe à valeurs complexes et des processus déterministe périodique. En conclusion, nous montrons que ce modèle de particule et sa fonction d’onde associée sont compatibles avec la théorie de la double solution de de Broglie et la théorie de la double échelle que nous avons proposée récemment