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The choice of membership functions plays an essential role in the success of fuzzy systems. This is a complex problem due to the possible lack of knowledge when assigning punctual values as membership degrees. To face this handicap, we propose a methodology called Ignorance functions based Interval-Valued Fuzzy Decision Tree with genetic tuning, IIVFDT for(More)
[1] As it is known, the Abel transform has been proven to be a useful tool that offers the possibility to obtain vertical description of ionospheric electron density (among other neutral atmosphere parameters) through inversion of Global Positioning System (GPS) observations gathered by Low Earth Orbiters (LEO). This work is focused on extending the(More)
This work presents the first results obtained on real time positioning applying the algorithms developed by our research group and using the data from the IGS-RT network, in order to confirm previous feasibility studies. Real-time user receivers at hundreds of kilometres far from the nearest reference station, which achieve precise positioning after few(More)
A new diagram for SBAS integrity validation is presented in this paper. The proposed concept is a modification of the well known Stanford plot, where a 2D histogram shows the relationship of position errors against protection levels for a set of measurements using an all in view satellite selection. The method consists on a new representation (known here as(More)
Satellite Navigation has become a keystone for the development of Europe and its citizens. It is then essential to provide adequate educational programmes so to ensure a prepared workforce for the GNSS sector in Europe. In this context, ESA has launched a complete Satellite Navigation Educational program, called EDUNAV, aiming at providing up-to-date GNSS(More)
This paper presents an implementation of a post-process kinematic positioning technique similar to PPP (Precise Point Positioning) but based on a network of stations. This technique is independent of precise clock information because it estimates satellite clock offsets 'on-the-fly', and thence it only needs reasonable accurate orbits information (for(More)
Since the first railways were built, they have not ceased to increase their capacity for transport, speed and energy consumption. This paper presents a comparative study of how present-day railway drive systems perform. Special emphasis is placed on consumption and energy efficiency. By using theoretical computer simulation models, simulations are conducted(More)
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