A modified Lax-Wendroff correction for wave propagation in media described by Zener elements

A modified Lax-Wendroff correction for wave propagation in attenuating and dispersive media described by Zener elements is presented. As opposed to the full correction, this new technique is explicit and offers large computational savings. The technique may be applied to a wide variety of hyperbolic problems. Here, the concept is illustrated for wave propagation in visco-acoustic medi

Taller de geofísica : geomagnetisme

El magnetisme i en particular el camp magnètic de la Terra s'ensenya als alumnes des de la primària fins al batxillerat en diferents moments i amb un aprofundiment progressiu. Aquest article pretén complementar l'estudi del camp magnètic al batxillerat amb una acti-vitat pràctica sobre una tempesta magnètica enregistrada a l'Observatori de l'Ebre. El treball consta d'una introducció als conceptes bàsics que permeten comprendre el camp geomagnètic, les tempestes magnètiques i l'enregistrament que se'n fa en un ob-servatori magnètic. L'objectiu final serà donar una mesura de l'activitat magnètica. La re-solució d'un qüestionari ajudarà a reforçar aquests conceptes i facilitarà la mesura dels índexs d'activitat magnètica

Hub operations delay recovery based on cost optimisation - Dynamic cost indexing and waiting for passengers strategies

In this paper, two strategies for airlines’ operations at a hub are combined and analysed: dynamic cost indexing, to recover delay, and waiting for connecting passengers at the hub. Agent Based Modelling techniques have been used to model the airlines’ operations considering detailed passenger’s itineraries, an extended arrival manager operation with slot negotiation, and delay and uncertainty at different phases of the flights. Results show that, when optimising the total cost, there is a trade-off between connecting and non-connecting passengers with respect to the gate to gate trip time. Waiting for passengers arises as an interesting technique when minimising airline operating costs

CASSIOPEIA II D3.2 - Final technical report

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

CASSIOPEIA D4.3 - case study 3 report: hub connectivity-driven variable aircraft speeds

This document reports on how the CASSIOPEIA agent-based model has been developed, through a case study, to explore the use of dynamic cost indexing on flights arriving at a major European hub airport. A scenario that simulated many flights using dynamic cost indexing to recover delay to a residual of 10 minutes resulted in a considerable average cost saving achieved per flight

Differences in photosynthesis and terpene content in leaves and roots of wild-type and transgenic Arabidopsis thaliana plants

We investigated the hypotheses that two different varieties of Arabidopsis thaliana show differences in physiology and terpene production. The two varieties of A. thaliana used in this study were wild-type (WT) and transgenic line (CoxIV-FaNES I) genetically modified to emit nerolidol with linalool/nerolidol synthase (COX). Photosynthetic rate, electron transport rate, fluorescence, leaf volatile terpene contents and root volatile terpene contents were analyzed. For both types, we found co-eluting α-pinene+β-ocimene, limonene, and humulene in leaves; and in the roots we found co-eluting α-pinene+β-ocimene, sabinene+β-pinene, β-myrcene, limonene, and humulene. At the end of the growing cycle, COX plants tended to have lower pools of terpene compounds in their leaves, with 78.6% lower photosynthesis rates and 30.8% lower electron transport rates, compared with WT plants at that time. The maximal photochemical efficiency Fv/Fm was also significantly lower (25.5%) in COX plants, indicating that these varieties were more stressed than WT plants. However, COX plants had higher (239%) root terpene contents compared to WT plants. COX plants appear to favor root production of volatile terpenes rather than leaf production. Thus we conclude that there were significant differences between COX and WT plants in terms of terpenoid pools, stress status and physiology

Validation and reconstruction of flow meter data in the Barcelona water distribution network

12 páginas, 16 figuras, 1 tabla.-- El PDF es la versión pre-print.-- et al.This paper presents a signal analysis methodology to validate (detect) and reconstruct the missing and false data of a large set of flow meters in the telecontrol system of a water distribution network. The proposed methodology is based on two time-scale forecasting models: a daily model based on a ARIMA time series, while the 10-min model is based on distributing the daily flow using a 10-min demand pattern. The demand patterns have been determined using two methods: correlation analysis and an unsupervised fuzzy logic classification, named LAMDA algorithm. Finally, the proposed methodology has been applied to the Barcelona water distribution network, providing very good results.This work is part of a applied research project granted by ADASA and AGBAR companies. The authors also wish to thank the support received by the Research Commission of the Generalitat of Catalunya (Group SAC Ref. 2009 SGR 1491) and by CICYT (Ref. HYFA DPI2008-01996 and WATMAN DPI2009-13744) of Spanish Ministry of Education.Peer reviewe