1,721,049 research outputs found
Phase-Preserving SAR Processing for Interferometrical Applications: Results on SIR-C/X-SAR Data
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The global positioning system and the "golden hour": fast localization for immediate medical care
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Space-Based surface detection with differential synthetic aperture Radar interferometry: potentiality, simulations and preliminary investigations
No full textThe capability of measuring small crustal deformation by means of differential Synthetic Aperture Radar (SAR) interferometry (DIFSAR) is investigated in this work. After outlining the mathematical background inherent to the principles of differential SAR interferometry and showing the potential and limits of the information content of spaceborne DIFSAR data, the analysis of the impact of this technique is carried out on some interferometric couples gathered in 1996 by the ERS-I/ERS-2 (European Remote Sensing Satellite) tandem mission. The imaged scene is a portion of the Sannio-Matese mountainous area (Southern Italy). Suitable interferometric couples are processed and analyzed in order to show potentialities of detecting surface deformation by means of DIFSAR data, and derive qualitative information on the relationship between DIFSAR-based change detection and the time scale of crustal dynamics, by investigating the effectiveness of the technique as a function of the scene coherence. Preliminary results confirm the feasibility of the technique, even at the cost of sophisticated processing and careful error analysis
Passive and Active Calibrators Characterization by using a Spaceborne SAR System Simulator
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Closed-form and iterative solutions of the problem of the global positioning system
No full textThe four user unknowns (three coordinates and the user clock bias) of the global positioning system single-point code-range static positioning problem are evaluated by means of pseudorange measurements and a minimal number of satellites. The presented methodologies, not needing model linearization and computation of trial (initial) values of the unknowns, provide fast and reliable initialization of commercial global positioning system firmware, typically based on linearized models. The procedures are validated by analyzing numerical results on real global positioning system measurements. Good performance and rate of convergence with respect to other methodologies found in literature testify the cost-effectiveness of our approach
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