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Best student paper award ICRAT 2020; International audience; Moving object analysis is a constantly growing field with numerous concrete applications in terms of traffic understanding, prediction and simulation. While many algorithms and analytic processes exist, there are still areas of investigation with novel trajectory analysis methods. As such, the geometric information analyses data with respect to its statistical distribution along extracted dimensions. This opens new ways of gaining a better understanding of large and complex trajectory data sets while providing flexible data manipulations. In this paper, we report our investigations with the development of an interactive methodology based on the geometric information analytic process where users can analyze trajectories sets, cluster and deform them maintaining the actual statistical properties of the investigated trajectories. As a contribution, this paper shows how geometric information can provide novel support for trajectory analyses taking into account the statistical properties of the investigated clusters. We also provide recommendations of good usage of such techniques with actual examples validated by a a domain expert of air traffic flow analysis

International audience; Analyzing the electroencephalographic (EEG) signal of epileptic patients as part of their diagnosis is a very long and tedious operation. The most common technique used by medical teams is to visualize the raw signal in order to find pathological events such as interictal epileptic spikes (IESs) or abnormal oscillations. More and more efforts are being adopted to try to facilitate the work of doctors by automating this process. Our goal was to analyze signal density fields to improve the visualization and automatic detection of pathological events. We transformed the EEG signal into images on which we applied a convolution filter based on a Kernel Density Estimation (KDE). This method that we propose to call CKDE for Convolutional Kernel Density Estimation allowed the emergence of local density fields leading to a better visualization as well as automatic detection of IESs. Future work will be necessary to make this technique more efficient, but preliminary results are very encouraging and show a high performance compared to a visual inspection of the data or some other automatic detection techniques.

International audience; For the sake of Air Traffic Management modernization , civil aviation organizations are currently developing IPS for Aeronautical Safety Services in the new ATN/IPS infrastructure. This includes to define new airborne and ground-based communication systems capable of managing both air traffic services (ATS) and aeronautical operational communications (AOC) safety services. One of the main challenges in this new ATN/IPS network is the IPv6 mobility problem. This paper proposes a solution which takes both advantages of ground based Locator/Identifier Separation Protocol and Proxy Mobile IPv6 to manage all the aircraft mobility scenarios. A dedicated OMNeT++ simulation model is also provided and shows the performances of our solution.

Let G be a graph, for which each vertex is assigned one of k colors in {1, …, k}. A legal coloring requires that two adjacent vertices have two different colors. The minimum sum coloring problem (MSCP) consists of finding such a legal coloring with the smallest sum value, knowing that to each color is assigned an integer value from 1 to k. This paper presents a new memetic approach for this NP-hard problem. The proposed hybrid algorithm is based on a very small population, composed of only two individuals. Thanks to this small population, no selection operator needs to be defined, nor any replacement strategy. In order to prevent a premature convergence of the algorithm, alternative mechanisms are introduced based on an elitist approach. The local search introduced in the population based algorithm is split in two phases. The first one is based on the well known TabuCol algorithm and aims to reduce the number of conflicting vertices. The second one, which is used to improve the total sum value, implements an efficient 2-move local operator. The proposed approach was successfully applied on many graphs from the reference COLORS02 and DIMACS benchmarks. It allowed to achieve most of the best known results, and to overpass the best known results for 15 challenging graphs.

International audience; A preliminary study on estimating aerodynamic forces of a Vertical/Short Takeoff and Landing (V/STOL) mini Unmanned Air Vehicle (UAV) configuration with Distributed Electric Propulsion (DEP) system is presented. The main objective is to offer the next generation fixed wing mini UAV aircraft configuration with high-speed cruise flight and vertical takeoff capabilities. The proposed concept uses four electric motors and propellers combination located on the leading edge of the wing. The described method uses semi-empirical formulations in order to estimate the forces and moments generated by the wing immersed in its distributed propeller slip-streams. Actuator disk theory is used for the propeller slipstream, where the thrust is assumed to be known for the calculations. Upwash of the fuselage and each propeller slipstream are taken into account for the wing and propeller inflow angle calculations. The resulting method, which is written as a program, serves as a conceptual design program for this type of configuration. Additionally, the program will be used for generating data for flight dynamics simulations. A candidate design is also presented, which is being manufactured for the ongoing developments and tests.

International audience; Airports Terminal Maneuvering Areas (TMA) and Control Traffic Regions (CTR) are characterized by a dense air traffic flow with high complexity. In nominal operations, approach flight path safety management consists in procedures which guide the aircraft to intercept the final approach axis, and the runway slope with an expected configuration in order to land. Some abnormal flights are observed and considered as Non Compliant when the intermediate and the final leg intercepting conditions do not comply with the prescription of the operational documentation. This kind of trajectories generates difficulties for both crew and Air Traffic Control (ATC) and may induce undesirable events such as Non Stabilized Approaches or ultimate events like Control Flight Into Terrain (CFIT), in the worst cases. There is a real need for atypical flights detection tools in order to improve safety. In this paper, a post-operational detection method based on functional principal component analysis and unsupervised learning will be presented and compared to geometric features.

International audience; For GNSS systems, the gain, phase and group-delay patterns of the receiver antenna have an impact on the pseudo-ranges, i.e. the apparent distances to the satellites estimated by the receiver. In the presence of multipath, this impact is difficult to assess because multipath and antenna effects are mixed. In this article, these sources of pseudo-range error are analyzed by means of simulations for an aircraft moving at the surface of an airport. For the simulations, we rely on a hybrid statistical-deterministic GNSS multipath simulator combined with a receiver simulator. Various antenna models are tested, e.g. an ideal isotropic antenna and a realistic antenna mounted on an aircraft, with and without the phase and group-delay patterns.

International audience

While visual cues are traditionally used for visual analytics, multimodal interaction technologies offer many new possibilities. This chapter explores the opportunities and challenges for developers and users to utilize and represent data through non-visual sensory channels to help them understand and interact with data. Users are able to experience data in new ways: variables from complex datasets can be conveyed through different senses; presentations are more accessible to people with vision impairment and can be personalized to specific user needs; interactions can involve multiple senses to provide natural and transparent methods. All these techniques enable users to obtain a better understanding of the underlying information. While the emphasis of this chapter is towards non-visual immersive analytics, we include a discussion on how visual presentations are integrated with different modalities, and the opportunities of mixing several sensory signals, including the visual domain.

International audience; This paper deals with the improvement of the robustness of heuristic solutions for aviation systems affected by uncertainty when the resolution of conflicts is implemented. A framework that includes the use of optimization and simulation is described which in turn generates pseudo-optimal schedules. The initial solution is progressively improved by iteratively evaluating the uncertainty in the generated solutions and calibrating in accordance with the objective function. Simulation is used for testing the feasibility of a solution generated by an optimization algorithm in an environment characterized by uncertainty. The results show that the methodology is able to improve solutions for the scenarios with uncertainty, thus making them excellent candidates for being implemented in real environments.

International audience; In general, the carrier phase of orthogonal frequency division multiplexing (OFDM) signals is not tracked for at least two reasons. First, the dc component of most baseband OFDM symbols is a null subcarrier so as to avoid the effect of dc bias at reception. Second, generation and transmission of OFDM symbols are independent from one symbol to next. As a result, no phase continuity is required to be maintained at any subcarriers. For communications, demodulation of OFDM symbols with cyclic prefix (CP) is tolerant to small timing errors and insensitive to the absolute phase but relative phase at data subcarriers, which can be easily calibrated with the help of pilot subcarriers. However, the OFDM signaling adopted by the Terrestrial Digital Video Broadcast (DVB-T) retains the dc component. Besides, the CP duration is specified in such a way that a whole number of cycles is ensured for the middle carrier. It happens in DVB- T that the middle carrier is assigned as a continual pilot subcarrier, which has a constant value across OFDM symbols. As a result, the baseband center frequency (dc component) has no phase discontinuity, which gives rise to the opportunity for carrier phase tracking. Carrier phase tracking has the potential to provide more accurate timing for ranging and ultimately for positioning than cross-correlation of CP and pilot subcarriers in coarse and fine time of arrival (TOA) estimation, respectively. In this paper, in-the air DVB-T signals collected in experimental tests are used to show the functionality and performance of DVB-T signal carrier phase tracking.

According to a 2013 AUVSI report, delays in integrating Unmanned Aerial Systems (UAS) into the National Airspace System (NAS) could cost more than $10 billions a year for the United States alone. Worldwide regulatory bodies are under pressure by the UAS industry to accelerate the regulation process, but safety remains their main objective. One condition for the safe introduction of UAS in the NAS is for them to be equipped with a collision avoidance system. Though the existing Airborne Collision Avoidance System II (ACAS II) could have been an option, the transformations of air traffic management engaged through NextGen (US) and SESAR (Europe) led to the definition of a new ACAS based on new logics, namely ACAS X. Its definition contains in particular two variations : ACAS Xa, for large aircraft, and ACAS Xu, for unmanned aircraft. As noted in a 2014 RTCA annual report, divide in technological knowledge between those experienced in ACAS II and those involved in the development of ACAS X is a concern. To help preventing this divide we believe it is essential to keep the community updated with the latest evolutions of the ACAS X standards. As work on Minimum Operational Performance Standards (MOPS) for ACAS Xu just started, it is of interest to know which parts of the MOPS are already decided, which remain flexible for the industries to make the difference and which are open research problems. Being a member of the ACAS X family, ACAS Xu lays on the same foundations as the well defined ACAS Xa standard. This work proposes an introduction to the ACAS Xa/Xu common basis, as it is unlikely to change, including the general architecture and Collision Avoidance (CA) logics. It is followed by a presentation of concepts specific to ACAS Xu such as the tailored threat logic, horizontal CA logic, CA coordination and automatic responses. For the flexible part, we believe it mainly concerns the surveillance sources. Instead of a precise standard, the regulation is likely to ask for requirements on the sensors capabilities. A state of the art of recent works allows proposing minimum sensor performances and focusing on an essential set of sensors. This work is concluded by presenting future challenges that need to be addressed to build a safe ACAS Xu baseline and to extend it to smaller and lower altitude UAS.

International audience; UAV Ad hoc NETworks (UAANET) are a new form of ad hoc networks in which nodes are Unmanned Aerial Vehicles (UAVs) and Ground Control Station (GCS). Although this field generated a certain interest in the scientific community, it has only received a modest contribution. Compared to Mobile Ad hoc NETworks (MANET), this new network paradigm has some unique features and brings specific challenges such as node mobility degree, network connectivity patterns, delay-sensitive applications and network security. Indeed, some UAV communication architectures have been proposed, but none of them has been designed with security in mind. This lack of scientific investigation can make the certification of UAANETs difficult to obtain. In this paper, we present our vision of such a challenge and the research that we are conducting to reach this objective. The aim is to propose an original secure routing protocol for UAVs using a MDD (Model Driven Development) approach which will ease the certification of final UAV products. The first preliminary results concerning our secure-routing protocol design will be presented. This paper describes our ongoing research which will provide secure communications for UAV ad hoc networks at the end of the SUANET (Secure Uav Ad-hoc NETwork) project.

International audience; In this paper, we report on our exploration of 3D representations to support temporal navigation. We ground our discussion in a user study on the design of a tool that helps airliner pilots to manage dangerous and tall thunderstorm cells. The tool enables pilots to visualize thunderstorm cells, navigate into meteorological predictions in the near future and evaluate safe paths . The visualization is provided on the dual 2D horizontal/vertical view that is already used on the flight deck. In lieu of t he standard 2D vertical view, the tool use s a 3D view t hat facilitates tracking of cells sliding along time slots and altitudes. The user navigates along two dimensions, heading and time slots, thanks to a rotary knob - button. The design is grounded in field studies with pilots. Prototypes have been iteratively evaluated during design walkthrough sessions with pilots. From the preliminary results of this study, we draw research questions related to the need of 3D in the cockpit navigation displays

Be it snow, volcanic ash or strikes, crisis events impose high costs on the air transport system and society. Airlines have progressively learned to mitigate the irregular operations arising from such events through procedures such as Collaborative Decision Making (CDM) for traffic flow and airport departure management; however the passenger's door-to-door journey during difficult times often remains unpleasant. Meta-CDM (Multimodal, Efficient Transportation in Airports and Collaborative Decision Making), aims at taking a passenger-centric approach when examining how airside and landside CDM can be interlinked with other transport modes to minimize the impact of severe disruptions. In this paper, we provide a preliminary analysis of past successes and failures of passenger-centric operations, by documenting the state of the art in airport CDM, by investigating representative disruptive events and by studying the conditions of development of airport intermodality. In addition, as the success or failure of any new concept depends on which metrics it is being evaluated against, we also discuss the need of relevant KPIs to measure the success of an extended CDM concept.

International audience; When visually exploring a multidimensional dataset with a 2D visualization (e.g. scatterplots), us-ers may switch views with a smooth 3D rotation. We identified three expected benefits of such transitions: tracking graphical marks, understanding their relative arrangements, and perceiving structural elements. We studied existing implementations of progressive 3D rotation and found problems that prevent those benefits when dealing with dense scenes. To address this issue, we propose an improvement by wisely placing the rotation axis. We performed two controlled experi-ments, which confirm the expected benefits and validate our improvements to the technique. Based on these experiment results, we describe a set of interaction techniques to control the rota-tion axis placement and apply them to the exploration of aircraft data.

International audience; We propose a new method for RCS computation of long internally complex dielectric objects such as wind turbine blades. The method proposed here is an improved iterative algorithm whose convergence is proven. Thanks to the geometrical decomposition technique, three accelerating methods can be used efficiently in an iterative algorithm. The first accelerating method allows the elimination of the internal degrees of freedom with minimal cost. The second accelerating method (matrix compression QR) accelerates all the matrix vector products used in the preconditioning procedure as well as in the GMRES iterative resolution. The third accelerating method consists in using a "geometric neighboring" preconditioner adapted to the physical aspect of the problem.

Paparazzi is a free open source software package for Unmanned (Air) Vehicle Systems. For many years, the system has been used successfully by hobbyists, universities and companies all over the world, on vehicles of various sizes (11.9g to 25kg). Paparazzi supports fixed wing, rotorcraft, hybrids, flapping vehicles and it is even possible to use it for boats and surface vehicles.

International audience; La congestion des infrastructures de transport est présentée par la commission européenne dans son dernier livre blanc sur les transports (2001) comme un frein à la croissance dans l'union européenne. Nous allons nous efforcer ici de présenter les facettes du problème de la congestion aéroportuaire, d'en montrer la complexité, et enfin de présenter quelques pistes qui sont étudiées aujourd'hui afin d'optimiser l'usage d'infrastructures qui ne suffisent plus à répondre à la demande.

International audience; The current allocation of slots on congested European airports constitutes an obstacle to the effective liberalisation of air transportation undertaken in Europe. With a view to favouring efficient slot utilisation and competition, as is the goal of the European commission, we propose to use a market mechanism, based on temporary utilisation licences. In order to allocate those licences, we propose and describe an iterated combinatorial auction mechanism where a percentage of licences would be reallocated each season. A secondary market would also be set up in order to reallocate slots during a season. Since a combinatorial auction involve a complex optimisation procedure, we describe how it can be made to work in the case of auctions.

A zoom operation in an eye tracking based graphical user interface, where the zoom operation, as initiated by a scroll wheel etc. takes place with respect to the focus of the user's attention as determined on the basis of eye tracking data. Mechanisms for determining the point of attention based on a sliding window recording point of regard and subject to a variety of weighting functions are proposed.

International audience; Since decades, the number of aircraft accidents is continuously decreasing thanks to support systems and the introduction of automation. However, a drawback of this trend is that crews tend to be “automation addict” due to pressure and fatigue, which mean that they practice less and less manual flying. Also, an over-confidence in the automation can promote the occurrence of a particularly prominent typology of error: the failure of the crew to properly monitor the flight instruments, which can be particularly hazardous during the final approach phase. This paper describes an experiment that was undertaken to study pilot’s monitoring strategies thanks to eye tracking technology during manual approaches. We examined the relationship between visual patterns and flight performance (to find out if the approach was stabilized or not). The results show that gaze allocation of pilots who failed to stabilize their approach was sub-optimal. An analysis of the visual dispersion shows that they did not divide efficiently their visual attention compared to reference crew. Also, these pilots did not sufficiently gaze primary flight instruments requested to fly the approach (the attitude indicator, the localizer and the glide deviation scales). We assume that eye tracking may be a useful tool to improve pilots' monitoring strategies, for example gaze-training based on video clip showing experts’ visual pattern could help novice pilots to adopt appropriate gaze strategies.

National audience; Le contrôle aérien s'appuie sur un découpage de l'espace en volumes élémentaires que l'on appelle secteurs : des secteurs qui ont en charge des vols en phase de croisière (secteurs En-Route) et des secteurs qui ont en charge des vols en évolution, qui vont atterrir ou qui vont décoller (secteurs d'Approche). La recherche appliquée au domaine du trafic aérien se focalise en général sur l'augmentation de la capacité des secteurs et la sécurité. Depuis peu, les considérations écologiques et économiques sont venues se greffer aux études sur le sujet, rendant envisageables un certain nombre d'évolutions majeures du point de vue de l'ATM1 : changer les techniques de contrôle, les outils mis à disposition des contrôleurs ou les procédures aériennes. Cette communication propose une nouvelle approche dans la construction des procédures d'arrivée pour les secteurs d'Approche qui ne repose plus exclusivement sur la capacité des contrôleurs à séparer et à réguler des avions, mais également sur la capacité des systèmes à bord des avions à calculer des trajectoires optimales du point de vue notamment de la consommation de carburant. Nous proposons une structure d'arrivée en peigne qui permet de séparer des vols, de les réguler tout en les laissant voler selon des profils optimisés. Il reste alors à affecter les vols aux différentes branches du peigne de façon à maximiser la cadence d'utilisation des pistes tout en respectant des contraintes de séparation entre aéronefs à différents points identifiés de croisement des trajectoires.

International audience; Empirical studies related to air transport market show that airlines price discriminate when they are in a monopoly situation (Gale and Holmes, 1993). This is consistent with economic theory. Some empirical literature related to airline pricing shows however that airlines practice price discrimination even though they have limited monopoly market power (Dana 1998). Stavins (2001) shows that market concentration leads to a reduction in discount granted to tickets with restrictions, when those restrictions are used as discriminatory tools. The theory related to price discrimination is then controversial in air transport markets: price discrimination does not necessarily increase as the markets become more competitive.Beyond discrimination process, the pricing policy of an airline is based on revenue management. That is, the portfolio of prices supplied to customers varies according to revenue management imperative. In terms of revenue management, many European airlines use the Revenue Management System provided by Amadeus. The optimization process, basis of the RMS, uses only historical data of the company to maximise the revenue on each flight. It results in opening or closing classes during the life time of the flight booking, taking into account the load factor and the level of demand. During this optimisation process the competitive pressure exerted by airlines on the same route is never addressed. As a consequence, RM analysts daily observe competitive prices and adapt the pricing of their company. This leads to a sound homogenisation of airlines pricing strategies while competing on the market. This observation is contradictory with Netessine and Shumsky (2004) and Lua (2006) results. Netessine and Shumsky (2004) and Lua (2006) suggest that airlines should differentiate their strategies in order to maximize their revenue on a flight.Using French data on transatlantic routes, we estimate the direct effect of competition on the daily prices supplied by a selected airline. We focus our analysis on economy tickets in order to simplify this preliminary analysis. We find a statistical significant dependence between reservation date and the level of prices. We also control for the route and the departure day. These variables appear to have a significant influence on the level of prices. Finally, the prices supplied on the same routes by competitors in the previous days are statistically significant. This confirms RM analysts’ behaviour, although the sense of competitors’ price effect depends on the competitor. Thus our results are not perfectly opposite to Netessine and Shumsky (2004) and Lua (2006) findings. The next step of our analysis will consist in using a system of price equations, each of them corresponding to an airline, to better identify and assess the interactions between airlines. Then the global system of competition in price on the market into consideration will be analysed.

International audience; The variation of cognitive workload (CW) can considerably impact the probability of human er- ror due to distraction, mind-wandering or cognitive resources overload 1. Besides, a high level of anxiety can provoke dangerous situations when pilots are not able to take control ensuring total precision and safety. The objective of this work is to assess whether state-anxiety, generated by a social stressor, affects flight performance when the CW varies. Methodology Nineteen participants (22.7 ± 3.8 years) were included in our analysis. All of them were in posses- sion of the Private Pilot License, having at least a flying experience of 50 flight hours (141.3 ± 139.5 hours). The experiment took place in an AL-50 simulator and consisted in a dual-task scenario which required the simultaneous accomplishment of a pre-established flight plan and a secondary task. A previous training consisting in a similar dual task scenario was carried out. The established flight scenario lasted approximately 35 minutes, including a 24-minutes cruise phase. A strict timing for the flight instructions was specified. Speed (measured in knots), head- ing (degrees) and altitude (m) parameters were collected during the simulations (sampling rate of 1Hz). To evaluate the performance, any deviation greater than ± 5 units from the requested flight parameter was counted as an error. The secondary task consisted of pressing a 7 inches touch-screen as quickly as possible after hear- ing some numbers integrated among Air Traffic Control instructions unrelated to the flight plan, only to get a more realistic setting. The task was presented during the cruise and subdivided in two inter-subject counterbalanced phases of 12 minutes: Low Cognitive Workload (LCW), where participant was instructed to press the screen if the heard numbers meet a simple attribute (mag- nitude or parity); High Cognitive Workload (HCW) where the attribute depended on the color of the numbers displayed on the screen. The participant was filmed and involved in a competition with the other participants similarly to [2] in order to enhance the state-anxiety. Cognitive and somatic anxiety levels and self-confidence were measured by means of the CSAI-2R questionnaire [3]. An ANOVA was performed: 2 levels of CW: LCW and HCW and one between-subject factor: anxiety (2 groups according to a cluster analysis from CSAI-2R scores).

International audience; The increase in air traffic and the use of digital communications in ATM create a need for new communication solutions. In this article, we present an aeronautical ad hoc network which could be used to meet those needs. Being self configured, self healing and not needing a heavy ground infrastructure, such networks are cost-efficient and performant ways to transmit data between ground and aircraft. In the design of such a communication architecture, we used our own simulation tool to test the system and its performances which are promising. Both the physical and link layer are covered in our study, as well as the impact of path selection at the network level on the performance of the network as a whole.

International audience; This paper is aimed at detecting whether an oligopolistic industry facing an international competition can sustain collusion or whether international trade disciplines it to competition. To do so we consider a differentiated-products oligopoly model and we estimate both demand and supply sides of the industry under investigation. The empirical analysis is performed in four steps. In the first step, we build a mathematical representation of the working of the industry. The second step is devoted to the estimation of the model under the assumption that the market is competitive. The third step provides an estimation of the model when it is assumed that the main firms on the market are forming a cartel and, more specifically, are behaving like a monopoly. Finally, the fourth step consists in comparing the two estimations in their capacity to represent reality, i.e., detecting which of the conducts - competition or collusion - is the most statistically adequate to represent the working of the market. The main result is that, in the industry under consideration and regarding the period of interest, the competition model statistically performs better than the collusion model. The very innovative part of the analysis here lies in the use of a limited amount of information. Indeed we perform the estimation of the model based on data from only one firm of the oligopoly and some aggregated data, thanks to the specification and the role of the international side of the market.

International audience

International audience; Collision voidance systems are crucial for RPAS integration, yet comparing their performances remain difficult. We believe that using fast time simulations and standard evaluation metrics would facilitate their comparison while providing insight into their benefits. However, fast time simulations are often viewed as hard to set up and limited to large scale demonstrations. We believe even small experiments can take advantage of them with huge benefits. The aim of this work is to ease access to fast time simulations by providing explanations, examples and references to previous works and to free software. We also list commonly used evaluation metrics for collision avoidance system performance ranking. By easing the setup of fast time simulation experiments, we believe future works will be able to provide their results in a more detailed and comparable form.

International audience; This paper studies the impact of clock sampling jitter on signal tracking in a dual band L5/E5 and L1/E1 Direct Sampling GNSS receiver designed for Civil Aviation. A model of the sampling clock jitter due to thermal noise is established and related simulation results about the phase tracking error standard deviation at the output of the PLL are presented.

National audience

International audience; Terminal Maneuvering Area (TMA) is one of the most complex and busiest airspaces where the air traffic is managed with the help of decision support tools such as Arrival Manager (AMAN) in many airports. The objective of AMAN involves regulating the inbound air traffic flow and providingthe expected scheduled time for each flight considering the impact of the enviro nment. As we know, the aircraft scheduling problem is NP-hard and requires the implementation of advanced algorithms. The heuristic algorithms are more likely to provide a quick and satisfying result, in which simulated annealing (SA) has been proven to be efficient and easily adapted to a complex problem that involves large-dimensional state-space. Previously, in our work [1], the problem is considered from a centralized point of view in which the integrated information of all flights is investigated. The optimization process involves population-based and computational consuming evaluation for each simulation. Considering the isolated decisions of each flight, it is evident that the system is naturally distributed. By focusing on the individual performance of each flight, the optimization process can be guided with prioritization and no integration of flight information is required, therefore the efficiency and flexibility of the algorithm will be increased. Since the centralized and distributed AMAN develop different implementations for simulated annealing, the properties of both adapted algorithms are demonstrated. The performances are analyzed in terms of the execution time and quality of result based on a case study on Paris-Charles de Gaulle airport.

Mathematical programming problems involving nonconvexities are usually solved to optimality using a (spatial) Branch-and-Bound algorithm. Algorithmic e?ciency depends on many factors, among which the widths of the bounding box for the problem variables at each Branch-and-Bound node naturally plays a critical role. The practically fastest box-tightening algorithm is known as FBBT (Feasibility-Based Bounds Tightening): an iterative procedure to tighten the variable ranges. Depending on the instance, FBBT may not converge ?nitely to its limit ranges, even in the case of linear constraints. Tolerance-based termination criteria yield ?nite termination, but not in worstcase polynomial-time. We model FBBT by using ?xed-point equations in terms of the variable bounding box, and we treat these equations as constraints of an auxiliary mathematical program. We demonstrate that the auxiliary mathematical problem is a linear program, which can of course be solved in polynomial time. We demonstrate the usefulness of our approach by improving an existing Branch-and-Bound implementation. global optimization, MINLP, spatial Branch-and-Bound, range reduction.

International audience; Cet article présente une infrastructure de sécurité adaptée au contexte aéronautique. Différentes spécificités propres aux communications aéronautiques sont prises en compte comme l'hétérogénéité du trafic, la priorité entre les flux gérés ainsi que l'évolution des ressources réseaux disponibles. La politique de sécurité proposée est ainsi dynamique et optimisée.

International audience; nnovation labs seems to become part of airports business models. Interestingly, the type of innovations developed are completely different from one platform to another. This suggests that a classification could be helpful, especially when public investment is also concerned. We propose in this paper, in the light of the case study of the hydrogen production at Toulouse Blagnac airport, a methodology to classify the innovations at airports. This classification is supported by a literature review on sustainable and disruptive innovations theories, which helps us identifying factors that drive and characterize these innovations and checking the relevancy of these factors for our case study

A graphics processor in which vertex records additionally comprise a texture index, referring to a position in a texture index table. This position is used to store a dynamic characterising value for that vertex. When a render target processes the vertices to render a respective image, it does so in a manner modulated by the corresponding dynamic characterising value retrieved from the texture index buffer in for a preceding iteration of the image generation, while an additional texture index render target retrieve the value from the texture index buffer for each vertex record under consideration and to copy it into the texture index copy buffer for the next iteration. A number of selection mechanisms based on the positioning of containers in the image space are presented, using the dynamic characterising value to register selections and render images accordingly., L'invention concerne un processeur graphique dans lequel des enregistrements de sommet comprennent en outre un index de texture, se référant à une position dans une table d'index de texture. Ladite position est utilisée pour stocker une valeur de caractérisation dynamique pour ledit sommet. Lorsqu'une cible de rendu traite les sommets pour rendre une image respective, elle ne fonctionne pas de manière modulée par la valeur de caractérisation dynamique correspondante extraite du tampon d'index de texture pour une itération précédente de la génération d'image, tandis qu'une cible de rendu d'index de texture supplémentaire extrait la valeur à partir du tampon d'index de texture pour chaque enregistrement de sommet considéré et pour copier celle-ci dans le tampon de copie d'index de texture pour l'itération suivante. Un certain nombre de mécanismes de sélection basés sur le positionnement de conteneurs dans l'espace d'image sont présentés, en utilisant la valeur de caractérisation dynamique pour enregistrer des sélections et rendre les

International audience; This paper describes the activities of ENAC (École Nationale de l’Aviation Civile), Toulouse, around the nanosatellites. Firstly, the TETX (Telemetry Earth Terminal X‐band) receiving antenna and itsaccompanying satellite signal processing unit are presented. Although educationally oriented, they constitute a fully operational ground station. Secondly, the mission control center dedicated to theEYESAT nanosatellite is described. Its development is also an important source of interesting educational projects

International audience; Self-tracking feedback with engaging and persuasive visualizations not only helps convey data but can also affect people's attitudes and behaviors. We investigate persuasive self-tracking feedback by augmenting data videos (DVs)-novel, engaging storytelling media. We introduce a new class of DVs, called Persuasive Data Videos (PDVs), by incorporating four persuasive elements-primary task, dialogue, system credibility, and social supports-drawn from the Persuasive System Design Model. We describe the iterative design of PDVs and a within-subjects preliminary validation to check their persuasive potential. We then assess PDVs' feasibility using the Persuasive Potential Questionnaire in a between-subjects study comparing a PDV against a conventional DV on Amazon Mechanical Turk (N = 252). Our results indicate the feasibility of using PDVs in providing individuals' self-tracking feedback to convey persuasive health messages, based on which we discuss opportunities for designing persuasive behavioral feedback in an engaging way.

International audience; At VOR or radar frequencies, the field scattered by a windturbine can illuminate nearby windturbines. This depends on the distance between the two windturbines and also on the frequency. This paper proposes an assessment of the shadowing effects between two windturbines at VOR and radar frequencies for typical distances. The interactions between the windturbines is shown to be negligible at VOR frequency while at radarfrequencies, it is not the case.

International audience; The presented work is focusing on the wind estimation and airframe identification based on real flight experiments as part of the SkyScanner project. The overall objective of this project is to estimate the local wind field in order to study the formation of cumulus-type clouds with a fleet of autonomous mini-UAVs involving many aspects including flight control and energy harvesting. For this purpose, a small UAV has been equipped with airspeed and angle of attack sensors. Flight data are recorded on-board at high speed for post-analyses. An approach based on Unscented Kalman Filter (UKF) is proposed for nonlinear wind estimation. As a first result, wind updraft estimation is highlighted by exploiting recorded flight test data. In addition to this, a motor test bench has been developed in order to establish a model of the propulsion system from wind tunnel experiments. It will be combined with a classical aerodynamic model for airframe identification Preliminary flight results are presented.

International audience; Nicolas Gruyer and Nathalie Lenoir discuss the current allocation of slots on congested European airport. In their eyes the system of grandfather rights constitutes an obstacle to the effective liberalisation of air transportation undertaken in Europe. In this article they propose to use a market mechanism, based on temporary utilisation licences. In order to allocate those licences, the proposed system is based on a combinatorial auction mechanism where a percentage of licences would be reallocated each season. A secondary market would also be set up in order to reallocate slots during a season. Since combinatorial auctions involve a complex optimisation procedure, we describe how it can be made to work in the case of auctions.

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International audience

International audience; Aircraft conflict detection and resolution is crucial in Air Traffic Management to guarantee air traffic safety. When aircraft sharing the same airspace are too close to each other according to their predicted trajectories, separation maneuvers have to be performed to avoid risks of collision. We propose new mixed-integer Nonlinear optimization models combining turnchanges and velocity-changes separation maneuvers. These separation maneuvers are performed by each aircraft at instant times which are decision variables of the problem, and each aircraft is allowed to perform only one type of maneuver. The pros and cons of the models are discussed.

International audience; Air transport was traditionally highly regulated, fragmented and protected. With European air transport market deregulation in the mid 1980s also airports could respond to new factors. Methodology developed within the FAST project analyzed evolution of airport strategies potential in the forthcoming decade in the frame of new airport typology reflecting different strategies depending on the airport size, market type and market potential.

National audience

International audience

Individuals differ in their ability to deal with unpredictable environments. Could impaired performances on learning an unpredictable cue-criteria relationship in a laboratory task be associated with impaired learning of complex skills in a natural setting? We focused on a multiple-cue probability learning (MCPL) laboratory task and on the natural setting of pilot training. We used data from three selection sessions and from the three corresponding selected pilot student classes of a national airline pilot selection and training system. First, applicants took an MCPL task at the selection stage (N = 556; N = 701; N = 412). Then, pilot trainees selected from the applicant pools (N = 44; N = 60; N = 28) followed the training for 2.5 to 3 yrs. Differences in final MCPL performance were associated with pilot training difficulties. Indeed, poor MCPL performers experienced almost twice as many pilot training difficulties as better MCPL performers (44.0% and 25.0%, respectively).

International audience