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Obesity is characterized by cardiometabolic and neurocognitive changes. However, how these two factors relate to each other in this population is unknown. We tested the association that cardiometabolic measures may have with impulse behaviors and white matter microstructure in adolescents with and without an excess weight. One hundred and eight adolescents (43 normal-weight and 65 overweight/obesity; 11–19 years old) were medically and psychologically (Temperament Character Inventory Revised, Three-Factor Eating Questionnaire-R18, Conners’ Continuous Performance Test-II, Stroop Color and Word Test, Wisconsin Card Sorting Test, Kirby Delay Discounting Task) evaluated. A subsample of participants (n = 56) underwent a brain magnetic resonance imaging acquisition. In adolescents, higher triglycerides and having a body mass index indicative of overweight/obesity predicted a more impulsive performance in Conners’ Continuous Performance Test-II (higher commission errors). In addition, higher glucose and diastolic blood pressure values predicted increments in the Three-Factor Eating Questionnaire-R18 emotional eating scale. Neuroanatomically, cingulum fractional anisotropy showed a negative relationship with glycated hemoglobin. The evaluation of the neurocognitive differences associated with obesity, usually based on body mass index, should be complemented with cardiometabolic measures.

Background/Objective. Excessive body weight has been related to lower cognitive performance. One of the mechanisms through which excess body weight may affect cognition is inflammation. Our study aims at distinguishing between the effects of body mass index (BMI) and those related to systemic inflammation on different aspects of cognition in adolescents with obesity and overweight. Subjects/Methods. One hundred and five adolescents with overweight or obesity between 12 and 21 years participated in the study. Levels of high sensitivity C-reactive protein, interleukin 6, tumour necrosis factors α (TNFα) and fibrinogen were determined from blood samples. Cognitive performance was evaluated, and six cognitive composites were obtained: working memory, cognitive flexibility, inhibitory control, decision-making, verbal memory, and fine motor speed. A single multivariate generalised lineal model was used to assess the influence of the four inflammatory biomarkers, as well as participants’ BMI, sex and age on the 6 cognitive indexes. Results. An inverse relationship between BMI and inhibitory control (F = 5.688, p = .019; β = − .212, p = .031), verbal memory (F = 5.404, p = .022; β = − .255, p = .009) and fine motor speed (F = 9.038, p = .003; β = − .319, p = .001) was observed. Levels of TNFα and fibrinogen were inversely related to inhibitory control (F = 5.055, p = .027; β = − .226, p = .021) and verbal memory (F = 4.732, p = .032; β = − .274, p = .005), respectively. Conclusions. Our data indicate that some components of executive functions, together with verbal memory, are sensitive to specific obesity-related inflammatory agents at early ages.

The ability to meet a controlled time of arrival during a continuous descent operation will enable environmentally friendly and fuel-efficient descent operations while simultaneously maintaining airport throughput. However, if the wind forecast used to compute the initial trajectory plan is not accurate enough, the guidance system will need to correct time deviations from the plan during the execution of the descent. Previous work proposed an onboard guidance strategy based on model predictive control, which repeatedly updates the trajectory plan in real-time from the current aircraft state and for the remainder of the descent. However, the wind conditions downstream, at altitudes not explored yet, were difficult to predict due to the lack of data. This paper shows the potential benefits of using wind observations, broadcast by nearby aircraft, to reconstruct the wind profile downstream. The wind profile in the trajectory optimization problem is modeled as a spline, control points of which are updated to fit the observations before replanning the trajectory. Results from simulations using realistic wind data show that the performance of model predictive control significantly improves when including up-to-date wind observations, in terms of time and energy errors at the metering fix and fuel consumption.

This paper presents an optimisation framework to compute the altitude and speed profiles of a trajectory in the execution phase of the flight, such that the expected total cost (ETC) of the operation is minimised (i.e. modelling the expected cost of delay and fuel – including arrival uncertainties – at the arrival gate). This is achieved with a two-stage optimisation strategy: a trajectory optimiser that minimises a generalised direct operating cost function, for a given cost index; and an upper-level optimiser, which obtains the best cost index that minimises the ETC. Several case studies are presented for different departure delays, while considering the impact of two different weather forecast updates too: a region with relative high head-winds appearing half way across teh flight; and a cold atmosphere scenario, with a tropopause altitude lower than standard conditions. ETC savings with respect to following the operational flight plan increase with departure delay, as expected. Due to the non-linearity of the cost function, however, the benefits of considering the weather update depend on the actual value of the departure delay, showing the convenience of integrating the proposed approach into a crew decision support tool in order to avoid sub-optimal decisions. This work has been performed as part of Pilot3 innovation action which has received funding from the Clean Sky 2Joint Undertaking (JU) under grant agreements No 863802. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and the Clean Sky 2 JU members other than the Union.

We address the situation where required times of arrival (RTAs) are assigned outside the feasible time window that allows aircraft to fly energy-neutral continuous descent operations (CDOs). Two strategies to achieve these RTAs are compared by means of simulated optimal trajectories and in terms of fuel consumption: powered descents along the published arrival route vs. energy-neutral CDOs along re-negotiated routes. A sensitivity study to different parameters led to results primarily for RTAs later than the estimated time of arrival. With strong-tailwind, stretching the route and flying neutral CDOs improves the efficiency of the operation. Light aircraft also benefit from being assigned longer pre-defined routes, while for heavy aircraft it is more efficient to fly powered descents along the published route. This paper could contribute to enhance ground-based decision support tools for air traffic controllers, aiming to manage arrival traffic more efficiently and reducing the overall environmental impact of arrival operations.

In this paper, we present a novel methodology to manage arrival traffic in terminal airspace. We define two areas around the airport, aiming to efficiently schedule incoming traffic. A four-dimensional (4D) trajectory negotiation/synchronization process between the air traffic control officer (ATCO) and the aircraft is performed in the pre-sequencing area, while the aircraft are still in the en-route phase of flight. On the other hand, in the dynamic-trajectories area, the ATCO, with the help of a ground support tool, generates dynamic arrival routes that automatically adapt to the current traffic demand. These arrival routes allow the aircraft to fly neutral continuous descent operations (CDOs, descents with idle thrust and no speed-brakes usage) and to ensure a separation throughout the arrival procedure. We choose a mixed-integer-programming approach to generate the arrival routes, while we formulate and solve an optimal control problem to generate a set of candidate CDOs per aircraft. Results show that, with a sufficient look-ahead time, it is possible to assign a required time of arrival (RTA) within each aircraft-arrival time window that would allow to efficiently schedule traffic even in the most challenging and dense scenarios. Besides improving efficiency of current operations in terminal airspace, the methodology presented in this paper could become a technical enabler towards an extended arrival manager (E-AMAN) with extended capabilities and, ultimately, to a fully deployed trajectory based operations (TBO) environment.

A European social contract is possible—if the discussion shifts from who has the right to act to who can help. Education is a striking example of Europe’s paradox: the areas that interest its citizens most—education, health, social protection—are those where EU institutions have the least competence. Yet while the main policy responsibility and funding instruments are at national or regional level, the key global trends in education and the reforms they require call for a strong effort from both the EU and its member countries: an extraordinary expansion of the demand for higher education and new skills; a renewed interest in the interaction between technology, education, and society, driven by the advancement of data analysis and artificial intelligence; and a growing concern about the role of education in reducing inequality and social exclusion. Education has a great future—but it will not be education as we know it; the credibility of Europe’s social contract will rest on its capacity to build and communicate the case for change and to articulate a guiding vision for twenty-first-century learning.

We present an automated emergency trajectory generator to compute the best emergency trajectory for a given landing site. A given emergency 2-dimensional (2D) path (i.e., route) is used as input for a trajectory predictor (TP), which computes a trajectory by taking into account the current aircraft performance and weather. The set of vertical profiles considered in the TP has been designed in order to cover the widest possible range of emergency situations. Moreover, the aircraft intents considered in these profiles are chosen by taking into account the operational requirements of the air traffic operation system and the input of the flight crew. A set of representative profiles has been tested during the study, to verify the result of the proposed algorithm and its computing time. Furthermore, the effect of the distance to go on the resulting trajectories has been also analyzed. This concept is expected to be part of an advanced flight management system on-board function to help the pilot take efficient and effective decisions in emergency situations and adverse conditions.

Continuous descent operations (CDOs) with required times of arrival (RTA) have been identified as a potential solution for reducing the environmental footprint of aviation in the terminal maneuvering area without compromising capacity. This paper assesses the feasibility of replacing current air traffic control sequencing and merging techniques, mainly based on path stretching and air holding, by a control based on RTA over metering fixes on known and fixed arrival routes. Because the remaining distance to the runway threshold is always known by the aircraft crew, this would allow engine-idle CDOs that do not require speed-brake usage and where only elevator control is used to meet the RTA. The assessment has been performed for Barcelona-El Prat Airport (Spain) using historical traffic demand data. The earliest and latest trajectories at a metering fix for each inbound aircraft were computed assuming engine-idle CDOs. Given the attainable RTA window for each aircraft, the aircraft sequencing problem was solved. The results show that assigning RTA allows optimizing the landing sequence when air traffic is low. For scenarios with high-traffic loads and late RTA assignments, path stretching still was found to be necessary. The minimum distance from the runway where inbound aircraft should receive the RTA to fully remove any radar vectoring was also analyzed. It was demonstrated that the assignment of RTA well before starting the descent would favor to enable full CDOs.

Standard state estimation techniques, either for linear or nonlinear systems, typically assume a perfect knowledge of the system, i.e., known process and measurement functions, and the corresponding noise statistics. The filter performance strongly depends on such knowledge and a possible model mismatch may lead to a significant performance degradation, but closed-form expressions for the resulting bias and covariance are not available. In this contribution, we explore the impact in extended Kalman filter approximations of a parametric model mismatch on both system functions and provide expressions for the estimator bias and covariance error induced by the mismatch. An illustrative example is shown to support the discussion.

This paper introduces a novel approach for synchronised demand-capacity balancing within a proposed Collaborative Air Traffic Flow Management framework. The approach is aimed to realise optimising traffic flow and scheduling airspace configuration in a more harmonised manner. Options such as delay assignment and alternative trajectories (generated and submitted by Airspace Users) are intended for regulating the traffic flow. Airspace reconfiguration involves, on the other side, adjusting the opening schemes of predefined configurations, or creating new ones (if needed) through dynamic sectorisation. Results suggest that, using the proposed approach, the required system delay can be reduced remarkably, whereas the number of opened sectors (and thus operating cost) and the total capacity provision (supplied by the Air Navigation Service Providers) decrease at the same time, due to the increased capacity utilisation per operating sector.

This paper proposes a collaborative air traffic flow management (ATFM) framework, in the scope of trajectory based operations, aiming to improve the cost-efficiency for airspace users (AUs) when facing ATFM regulations. The framework consists of four modules. The first one involves the AUs initially scheduling their preferred trajectories for all their flights. Based on this initial demand, the second module (assumed to be on the Network Manager -NM- side) detects time-varying hotspots (i.e. overloaded sectors along the day). In the third module, hotspot information is shared back to the AUs who plan alternative trajectory options to avoid crossing these congested airspace volumes (in the lateral and vertical domain); as well as providing to the NM different pre-tactical delay management preferences (including ground holding, linear holding, air holding and pre-tactical delay recovery); based on their internal cost breakdown structures. Incorporating all these potential combined options, the last module computes the best trajectory selections and the optimal distribution of delay assignments, such that the cost deviation from the initial status (all the user-preferred trajectories) is minimized. This model is formulated as mixed integer linear programming (MILP) and validated by a real-world case study focused on 24 h of traffic over the French airspace. Results using the proposed framework suggest a significant system delay reduction by nearly 97% over the existing method, whilst yielding an average of less than 100 kg extra fuel consumption and 50 Euro extra route charges for the 11% flights diverted to their alternative trajectories.

Continuous descent operations with controlled times of arrival at one or several metering fixes could enable environmentally friendly procedures without compromising terminal airspace capacity. This paper focuses on controlled time of arrival updates once the descent has been already initiated, assessing the feasible time window (and associated fuel consumption) of continuous descent operations requiring neither thrust nor speed-brake usage along the whole descent (i.e. only elevator control is used to achieve different metering times). Based on previous works, an optimal control problem is formulated and numerically solved. The earliest and latest times of arrival at the initial approach fix have been computed for the descent of an Airbus A320 under different scenarios, considering the potential altitudes and distances to go when receiving the controlled time of arrival update. The effects of the aircraft mass, initial speed, longitudinal wind and position of the initial approach fix on the time window have been also investigated. Results show that time windows about three minutes could be achieved for certain conditions, and that there is a trade-off between robustness facing controlled time of arrival updates during the descent and fuel consumption. Interestingly, minimum fuel trajectories almost correspond to those of minimum time.

A compromise solution to increase flight efficiency in cruise, but without penalising capacity (or even safety), would be perhaps to remove (or relax) the minimum rate of climb (ROC) constraint and/or to reduce the height of the step climbs in cruise. In this paper, the benefits (in terms of total operating costs) and the associated impact on the air traffic management (ATM) of such “relaxed cruise” operations are quantified for a representative medium-haul aircraft under different scenarios, by means of an in-house trajectory optimisation software. Results show that by reducing the minimum ROC from 500 to 300 ft min − 1 , whilst keeping the step climb height according to current reduced vertical separation minima (RVSM) standard would give a good compromise between cost savings and impact on the ATM.

This paper introduces a linear holding strategy based on prior works on cruise speed reduction, aimed at performing airborne delay at no extra fuel cost, as a complementary strategy to current ground and airborne holding strategies. Firstly, the equivalent speed concept is extended to climb and descent phases through an analysis of fuel consumption and speed from aircraft performance data. This gives an insight of the feasibility to implement the concept, differentiating the case where the cruise flight level initially requested is kept and the case where it can be changed before departure in order to maximize the linear holding time. Illustrative examples are given, where typical flights are simulated using an optimal trajectory generation tool where linear holding is maximized while keeping constant the initially planned fuel. Finally, the effects of linear holding are thoroughly assessed in terms of the vertical trajectory profiles, range of feasible speed intervals and trade-offs between fuel and time. Results show that the airborne delay increases significantly with nearly 3-fold time for short-haul flights and 2-fold for mid-hauls to the cases in prior works.

This paper presents an approach to implement linear holding (LH) for flights initially subject to ground holding, in the context of Trajectory Based Operations. The aim is to neutralize additional delays raised from the lack of coordination between various traffic management initiatives (TMIs) and without incurring extra fuel consumption. Firstly, motivated from previous works on the features of LH to absorb delays airborne, a potential applicability of LH to compensate part of the fixed ground holding is proposed. Then, the dynamic adjustment of LH in response to TMIs-associated tactical delays is formulated as a multi-stage aircraft trajectory optimization problem, addressing both pre- and post-departure additional delays. Results suggest that additional delays of 25 mins in a typical case study can be totally recovered at no extra fuel cost. A notable extent of delay reduction observed from the computational experiments further supports the benefits of LH for reducing different combinations of additional delays without consuming extra fuel.

Fuel consumption is one of the major considerations for both the impact of aviation in the environment and the cost of operations. This paper assesses the accuracy of a method capable of producing aircraft fuel estimates based on their 4D trajectory timestamps and the weather forecast. Fuel consumption estimates generated for 2448 descents are compared with the flight data recorder (FDR) values provided by the airline. Fuel consumption is estimated by taking the 4D trajectory from two different sources: the FDR system itself and surveillance radar tracks. In both cases, the Base of Aircraft Data (BADA) and a model that fits manufacturers’ performance data to polynomial functions are used to represent aircraft performance. Results obtained with the latter show that fuel usage could be estimated with an accuracy of 16 kg (4.8%) using the 4D trajectory as reported by the FDR system and 28 kg (7.8%) using surveillance radar observations. It is also observed that the BADA 3.6 model underestimates the fuel consumption, illustrating the need for an improved performance model in the terminal manoeuvring area. This method could be the cornerstone for the calculation of advanced performance indicators to measure flight efficiency (and environmental impact) in post-operational assessments, since it enables the estimation of the full state vector of an aircraft, including variables that are not explicitly included in the surveillance data (such the fuel, thrust, etc.).

This paper presents a mixed-integer programming approach to compute aircraft arrival routes in a terminal maneuvering area (TMA) with guaranteed temporal separation of all aircraft arriving within a given time period. Furthermore, the aircraft are assumed to be flying according to their optimal continous descent operation speed profile with idle thrust and no speed brakes usage. The arrival routes form a merge tree that satisfies several operational constraints; for example, all merge points are spatially separated. How the continuous descent operation speed profiles for different route lengths are computed is detailed. Experimental results are presented for calculation of fully automated continuous descent operation-enabled arrival routes during 1 h of operation on a busy day at a Stockholm terminal maneuvering area. The current framework successfully generates an arrival tree, merging the traffic from all TMA entry points to the runway for 30 min intervals. For a complete 1 h period, two trees (per 30 min) are computed that differ as little as possible.

Nowadays, regulations in Europe are applied at traffic volume (TV) level consisting in a reference location, i.e. a sector or an airport, and in some traffic flows, which act as directional traffic filters. This paper presents an enhanced demand and capacity balance (EDCB) formulation based on constrained capacities at traffic volume level. In addition, this approach considers alternative trajectories in order to capture the user driven preferences under the trajectory based operations scope. In fact, these alternative trajectories are assumed to be generated by the airspace users for those flights that cross regulated traffic volumes, where the demand is above the capacity. For every regulated trajectory the network manager requests two additional alternative trajectories to the airspace users, one for avoiding the regulated traffic volumes laterally and another for avoiding it vertically. This paper considers that the network manager allows more flexibility for the new alternative trajectories by removing restrictions in the Route Availability Document (RAD). All the regulated trajectories (and their alternatives) are considered together by the EDCB model in order to perform a centralised optimisation minimising the the cost deviation with respect to the initial traffic situation, considering fuel consumption, route charges and cost of delay. The EDCB model, based on Mixed-Integer Linear Programming (MILP), manages to balance the network applying ground delay, using alternative trajectories or both. A full day scenario over the ECAC area is simulated. The regulated traffic volumes are identified using historical data (based on 28th July of 2016) and the results show that the EDCB could reduce the minutes of delay by 70%. The cost of the regulations is reduced by 11.7%, due to the reduction of the delay, but also because of the savings in terms of fuel and route charges derived from alternative trajectories.

Analysis of punctuality of airport arrivals, as well as identification of causes of the delays within transition airspace, is an important step in evaluating performance of the Terminal Maneuvering Area (TMA) Air Navigation Ser- vices. In this work we analyse how different weather events influence arrival punctuality and vertical flight efficiency on example of Stockholm Arlanda airport. We quantify the impact of the deviations from the flight plans influenced by different weather events, by demonstrating that they result in significant arrival delays, vertical inefficiencies and calculating how much extra fuel is wasted due to vertical flight inefficiency within Stockholm TMA.

37th DASC Best of session (ATM-E: Automation) award 2018, concedit per l'Institute of Electrical and Electronics Engineers i American Institute of Aeronautics and Astronautics

This paper presents a method to introduce linear holding to flights affected by Airspace Flow Program (AFP) initiatives. Trajectories are optimized at their planning stage in such a way that the program performance is improved in terms of delay absorption before the congested area, and delay recovery at the destination airport. This recovery process is studied by comparing the case where the same fuel consumption is fixed as the nominal flight, with several cases where some extra fuel allowances are considered at the flight planning stage. The effects for AFP delayed flights are thoroughly discussed in a case study followed by a sensitivity analysis on possible influential factors. Results suggest that using the proposed method could partially recover part of the AFP delay, even with no extra fuel allowances (e.g., reducing 3.3 min of ground delay and 1.7 min of arrival delay for a typical short-haul flight). When extra fuel is allowed, however, the maximum delay recovery increases up to 10 min for the studied case, which also proves to be more cost-efficient than current operations, when flight speed is increased after experiencing all delay on ground

In the majority of situations, air traffic flow management (ATFM) regulations are issued due to weather-related capacity reductions. Considering the uncertainties in weather prediction and other unforeseen factors, ATFM decisions are typically conservative and the planned regulations may last longer than actually needed [1,2]. At present, ground delay is more preferable than airborne delay (holding) from safety, environmental, and operating cost points of view. However, when regulations are canceled before their initial planned ending time, as occur often [3,4], the already accomplished delay on ground cannot be recovered, or it can be partially recovered by increasing speed, leading to extra fuel consumption. To overcome this issue, a speed reduction (SR) strategy was proposed in [5], which aimed at partially absorbing ATFM delays airborne. Ground delayed aircraft were enabled to fly at the minimum fuel-consumption speed (typically slower than the nominal cruise speed initially chosen by the airline), performing in this way some airborne delay. At the same time, part of the fuel was saved with respect to the nominal flight. This strategy was further explored in [6], where aircraft were allowed to cruise at the lowest possible speed in such a way that the specific range (i.e., the distance flown per unit of fuel consumption) remained the same as initially planned. In this situation, if regulations were canceled, aircraft already airborne and flying slower could increase their cruise speed to the initially planned speed and recover part of the delay without extra fuel consumption [2,6–8]. In this paper, the SR strategy presented in [6] is extended in such a way that not only the cruise phase is used to perform linear holding but also the climb and descent phases are subject of optimization to maximize the total amount of airborne delay that can be achieved without incurring extra fuel costs. Three cases are studied: SR only in cruise; SR in the whole flight but keeping the nominal cruise altitude; and SR for the whole flight while also optimizing the cruise altitude to maximize delay.