865 research outputs found

    CASSIOPEIA II D3.2 - Final technical report

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    The FlightPath 2050 presents Europe’s Vision for Aviation for the future. In what refers to air traffic management, this vision includes concrete goals for the punctuality of flights and capacity of the air traffic management system. Additionally, the document adds a concrete goal in what refers to passenger mobility, stating that 90% of the passengers should be able to travel door-to-door in Europe within 4 hours. Passenger mobility is obviously the ultimate goal of the air transport system, which mission is to transport passengers and freight, not airplanes. However, punctuality is currently mostly measured as aircraft operations performance. Moreover, most air traffic management technology improvements are targeting aircraft punctuality and not passenger punctuality. Passenger punctuality depends critically on passenger connectivity, as a missed connection impacts very negatively in passenger mobility performance. Increasing the predictability of air transport operations has limits. Not only meteorological conditions can affect the punctuality but also countless operational hazards impact the air traffic management system. Making the system adaptable to changes in the operational conditions, capable of re-configuring itself to accommodate to a new scenario seems a better approach than trying to make the system robust, which ultimately could be too expensive or impossible. Studying how different mechanisms improve the adaptability of the system is a complex problem. On one hand, it is a challenge to design a procedure that provides adaptability without impacting other performance metrics of the system. On the other hand, complex mechanisms usually require dedicated simulation frameworks, capable of modelling realistically a large number of parameters as well as providing a performance framework capable of evaluating in detail (e.g. beyond simple statistical properties) how the system adapts to the new conditions and how those mechanisms target a performance goal. The CASSIOPEIA DCI-4HD2D project extension studied how changing the trajectory of each aircraft to either minimise fuel consumption or to minimise time to destination can be used as a adaptability mechanism, to work together with other ATM improvements, to address passenger connectivity. Understanding how this mechanism, known as Dynamic Cost Indexing (DCI), increases the adaptability of the system, required the analysis, design and implementation of a complex software system as a collection of interacting, autonomous agents. This document reports on the cases of study selected and the analysis of the outcome of the simulations performed, assessing how DCI contributes to passenger connectivity and, ultimately, to passenger mobility improvement

    Innovación digital en el aula de matemáticas: desarrollo de materiales docentes como apoyo en la enseñanza

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    La propuesta que se presenta forma parte de un proyecto de innovación docente, vinculado al servicio de producción e innovación digital de la Universidad de Salamanca, desarrollado en el curso 2015-16. En la asignatura de Matemáticas, cuyos contenidos tratan sobre Geometría y su didáctica, se generaron vídeos teórico prácticos, centrados en el recurso didáctico de la papiroflexia

    A multi-layer model for long-term KPI aligment forecast

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    This article presents a new holistic model for the air traffic management system built by the Vista project. The model studies the alignment and trade-offs of key performance indicators in the 2035 and 2050 horizons. It is based on three layers modelling the strategic, pre-tactical and tactical phases of ATM. It heavily features multi-agents, is highly data-driven, and includes highly microscopic models. It is runnable as a ‘what-if’ tool and has been applied to different scenarios, including long-term forecasts for 2035 and 2050. The results obtained with the model so far show clear trends, including surging emissions, an important reduction in delay uncertainty, and increases of flight plan buffer

    Vista D5.1 - Initial Assessment Report

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    This deliverable presents Vista’s model and its calibration. The features of each of the model layers (strategic, pre-tactical and tactical) are described along with their calibration. A total of 58 scenarios with four foreground factors are modelled. The results of the layers are produced independently to present the capabilities of the system. These initial results are described and the next steps identified

    Vista D5.2 - Final Assessment Report

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    Vista examines the effects of conflicting market forces on European performance in ATM, through the evaluation of impact metrics on four key stakeholders, and the environment. Vista models the current, 2035 and 2050 timeframes based on various factors and their potential evolution. Vista’s model covers the three temporal phases of ATM (strategic, pre-tactical and tactical), and represents a typical (busy) day of operations. The model is able to estimate the impact of factors on the different phases independently, allowing us to capture how indicators change under different scenarios and execution phases. This deliverable presents the final results obtained from the model, together with a detailed description of the various parts of the model, the analysis performed to prepare the data, and the model calibration

    Controlling fragmentation of the acetylene cation in the vacuum ultraviolet via transient molecular alignment

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereAn open-loop control scheme of molecular fragmentation based on transient molecular alignment combined with single-photon ionization induced by a shortwavelength free electron laser (FEL) is demonstrated for the acetylene cation. Photoelectron spectra are recorded, complementing the ion yield measurements, to demonstrate that such control is the consequence of changes in the electronic response with molecular orientation relative to the ionizing field. We show that stable C2H2 + cations are mainly produced when the molecules are parallel or nearly parallel to the FEL polarization, while the hydrogen fragmentation channel (C2H2 + → C2H+ + H) predominates when the molecule is perpendicular to that direction, thus allowing one to distinguish between the two photochemical processes. The experimental findings are supported by state-of-the art theoretical calculationsAn open-loop control scheme of molecular fragmentation based on transient molecular alignment combined with single-photon ionization induced by a shortwavelength free electron laser (FEL) is demonstrated for the acetylene cation. Photoelectron spectra are recorded, complementing the ion yield measurements, to demonstrate that such control is the consequence of changes in the electronic response with molecular orientation relative to the ionizing field. We show that stable C2H2 + cations are mainly produced when the molecules are parallel or nearly parallel to the FEL polarization, while the hydrogen fragmentation channel (C2H2 + → C2H+ + H) predominates when the molecule is perpendicular to that direction, thus allowing one to distinguish between the two photochemical processes. The experimental findings are supported by state-of-the art theoretical calculation

    Workers’ behavior after safety regulations: Impact evaluation of the Spanish Occupational Safety and Health Act

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    While the 1995 Occupational Safety and Health Act (OSH) regulation transformed the outlook on workplaces in Spain, characterized by a lack of preventive protection, public statistics have reported an increasing trend in the postregulation workplace accident rates. This study uses microdata from official national statistics to examine the effect of the OSH regulation on the reported accidents while focusing on its severity. Accordingly, we apply a difference-in-difference assessment method where a comparable group is formed by the contemporaneous in itinere accidents (commuting), which are legally and statistically considered work-related accidents but not directly impacted by the OSH regulation, with a focus on the workplace environment. The results reveal that the nonfatal accident rate decreased after the implementation of the regulation. However, when we isolate the effect of the regulation on accidents that usually provoke hard-to-diagnose injuries (dislocations, back pain, sprains, and strains), we obtain a significant increase in the accident rate. Moral hazard mixed effects seem to have played a crucial role in these dynamics through overreporting and/or Peltzman effects, often offsetting accident reduction intended by the OSH regulation

    17 new very low-mass members in Taurus. The brown dwarf deficit revisited

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    Recent studies of the substellar population in the Taurus cloud have revealed a deficit of brown dwarfs (BD) compared to the Trapezium cluster population (Briceno et al 1998; Luhman 2000; Luhman et al 2003a; Luhman 2004). However, these works have concentrated on the highest stellar density regions of the Taurus cloud. We have performed a large scale optical survey of this region, covering a total area of 30 deg^2, and encompassing the densest part of the cloud as well as their surroundings, down to a mass detection limits of 15 Jupiter Masses (MJ). In this paper, we present the optical spectroscopic follow-up observations of 97 photometrically selected potential new low-mass Taurus members, of which 27 are strong late-M (SpT < M4V) candidates. These observations reveal 5 new very low mass (VLM) Taurus members and 12 new BDs. Combining our observations with previously published results, we derive an updated substellar to stellar ratio in Taurus of Rss =0.23 +/- 0.05. This ratio now appears consistent with the value previously derived in the Trapezium cluster under similar assumptions of 0.26 +/- 0.04. We find strong indication that the relative numbers of BDs with respect to stars is decreased by a factor 2 in the central regions of the aggregates with respect to the more distributed population. Our findings are best explained in the context of the embryo-ejection model where brown dwarfs originate from dynamical interactions in small N unstable multiple systems.Comment: 20 pages, 15 figure

    A young binary Brown Dwarf in the R-CrA star formation region

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    We present imaging and spectroscopic observations with HST (WFPC2, ACS/HRC and STIS), VLT (FORS2) and Keck (HIRES) of the dM8 ultra-cool dwarf DENIS-P J185950.9-370632, located in the R-CrA region. The presence of lithium absorption at 670.8 nm and the strong Halpha emission indicate a young age and a sub-stellar mass. Our diffraction-limited images resolve a companion at the separation limit of HST/ACS (~0.06"). The 2.1 mJy flux in the LW2 filter (5.0-8.5 microns) of the Infrared Space Observatory (see 1999A&A...350..883) likely corresponds to an infrared excess, suggesting the presence of circumstellar material. Proper motion and photometric measurements, as well as the Halpha activity, confirm membership in the R-CrA star forming region. If confirmed by further observations, DENIS-P J185950.9-370632 would be the first accreting sub-stellar multiple system observed to date.Comment: 18 pages, 11 figures, 3 tables Version with full resolution figures available on: ftp://ftp.mpe.mpg.de/people/hbouy/publications/DENIS1859.ps.g
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