Search results for "Application"
showing 10 items of 5559 documents
Interactive simulation of one-dimensional flexible parts
2006
Computer simulations play an ever growing role for the development of automotive products. Assembly simulation, as well as many other processes, are used systematically even before the first physical prototype of a vehicle is built in order to check whether particular components can be assembled easily or whether another part is in the way. Usually, this kind of simulation is limited to rigid bodies. However, a vehicle contains a multitude of flexible parts of various types: cables, hoses, carpets, seat surfaces, insulations, weatherstrips... Since most of the problems using these simulations concern one-dimensional components and since an intuitive tool for cable routing is still needed, w…
Antimicrobial Activity Characterization in a Heterogeneous Group of Compounds
1998
In this work we carry out a study of pattern recognition to detect the microbiological activity in a group of heterogeneous compounds. The structural descriptors utilized are the topological connectivity indexes. The methods followed are stepwise linear discriminant analysis (linear analysis) and artificial neural network (nonlinear analysis). Although both methods are appropriate to differentiate between active and inactive compounds, the artificial neural network is, in this case, more adequate, since it shows in a test set a prediction success of 98%, versus 92% obtained with linear discriminant analysis.
Experimental Sentinel-2 LAI estimation using parametric, non-parametric and physical retrieval methods – A comparison
2015
Abstract Given the forthcoming availability of Sentinel-2 (S2) images, this paper provides a systematic comparison of retrieval accuracy and processing speed of a multitude of parametric, non-parametric and physically-based retrieval methods using simulated S2 data. An experimental field dataset (SPARC), collected at the agricultural site of Barrax (Spain), was used to evaluate different retrieval methods on their ability to estimate leaf area index (LAI). With regard to parametric methods, all possible band combinations for several two-band and three-band index formulations and a linear regression fitting function have been evaluated. From a set of over ten thousand indices evaluated, the …
Rilievo e ricostruzione virtuale del Ponte Sud di Hierapolis di Frigia (Turchia)
2015
[ES] El artículo se refiere al levantamiento topográfico y la reconstrucción en 3D de un puente-acueducto romano situado inmediatamente al sur de Hierápolis, en Frigia (suroeste de Turquía), a lo largo del antiguo camino dirigido a Colosas, en el interior de Anatolia. Actualmente sólo se conservan su pilar sur y escasos restos del pilar norte. Se encuentra en una situación muy difícil, en el interior de un valle estrecho y profundo, y nunca se ha estudiado antes. Durante la campaña de trabajo de campo de 2011 de la Misión Arqueológica Italiana, fue examinado con un diferencial de alta precisión del sistema GPS (para la documentación del plan y su posicionamiento en el mapa digital arqueológ…
Discovering learning paths on a domain ontology using natural language interaction
2005
The present work investigates the problem of determining a learning path inside a suitable domain ontology. The proposed approach enables the user of a web learning application to interact with the system using natural language in order to browse the ontology itself. The course related knowledge is arranged as a three level hierarchy: content level, symbolic level, and conceptual level bridging the previous ones. The implementation of the ontological, the interaction, and the presentation component inside the TutorJ system is explained, and the first results are presented.
On the Intrinsic Complexity of Learning
1995
AbstractA new view of learning is presented. The basis of this view is a natural notion of reduction. We prove completeness and relative difficulty results. An infinite hierarchy of intrinsically more and more difficult to learn concepts is presented. Our results indicate that the complexity notion captured by our new notion of reduction differs dramatically from the traditional studies of the complexity of the algorithms performing learning tasks.
Measuring dissatisfaction with coauthorship: An empirical approach based on the researchers’ perception
2019
Abstract Increasing levels of collaboration constitute one of the characteristics of science. However, the knowledge production system is based on a fundamental discordance: on the one hand, it is cooperative in nature, with links articulated through coauthorships, and on the other, the systems for assigning merit and distributing rewards function on an individual scale. This contradiction can give rise to dysfunction and inappropriate practices. This study analyses researchers’ perceptions about the problems associated with authorship in scientific publications. We make use of a coauthorship dissatisfaction index that measures the degree of dissatisfaction with the author order on the byli…
Evolution of the surface magnetic field of rotating proto-neutron stars
2017
We study the evolution of the field on the surface of proto-neutron stars in the immediate aftermath of stellar core collapse by analyzing the results of self-consistent, axisymmetric simulations of the cores of rapidly rotating high-mass stars. To this end, we compare the field topology and the angular spectra of the poloidal and toroidal field components over a time of about one seconds for cores. Both components are characterized by a complex geometry with high power at intermediate angular scales. The structure is mostly the result of the accretion of magnetic flux embedded in the matter falling through the turbulent post-shock layer onto the PNS. Our results may help to guide further s…
Numerical simulations of dynamics and emission from relativistic astrophysical jets
2013
Broadband emission from relativistic outflows (jets) of active galactic nuclei (AGN) and gamma-ray bursts (GRBs) contains valuable information about the nature of the jet itself, and about the central engine which launches it. Using special relativistic hydrodynamics and magnetohydronamics simulations we study the dynamics of the jet and its interaction with the surrounding medium. The observational signature of the simulated jets is computed using a radiative transfer code developed specifically for the purpose of computing multi-wavelength, time-dependent, non-thermal emission from astrophysical plasmas. We present results of a series of long-term projects devoted to understanding the dyn…
LOFT - A large observatory for x-ray timing
2010
The high time resolution observations of the X-ray sky hold the key to a number of diagnostics of fundamental physics, some of which are unaccessible to other types of investigations, such as those based on imaging and spectroscopy. Revealing strong gravitational field effects, measuring the mass and spin of black holes and the equation of state of ultradense matter are among the goals of such observations. At present prospects for future, non-focused X-ray timing experiments following the exciting age of RXTE/PCA are uncertain. Technological limitations are unavoidably faced in the conception and development of experiments with effective area of several square meters, as needed in order to…