1,720,965 research outputs found
Design and Test-bed Implementation of a Reconfigurable Receiver for Navigation Applications
No full textSDR Technology Applied to Galileo Receivers
No full textIt has been worldwide recognized that under the push of the research activity related to Galileo and to the future GPS (Global Positioning System), the satellite navigation market is growing in importance for different civil applications. In order to deal with future developments and improvements of GNSS, advanced receiver architectures providing the enhanced performances will be needed. For these reasons, it is interesting to devise smart approaches to the design of navigation receivers assuring a certain degree of reconfigurability and portability in order to deal with new GNSS scenarios (e.g., integration between navigation and communication services). In this paper we discuss a receiver architecture based on Software Defined Radio (SDR) technique. The main peculiarity of SDR is to allow for developing of flexible devices in which the receiver functionalities are softwareimplemented in a modular architecture. The present technology does not allow a totally software receiver, but the development of fast and reliable electronics make the SDR approach an interesting perspective. Note that great attention has been devoted to the applicability of SDR techniques in order to design reconfigurable personal communication terminals, leaving unexplored the potentialities of SDR for other terminals as navigation receiver, or integrated hybrid communications/navigation receivers. The main objective of this work is to explore innovative approaches and new technologies in the area of satellite navigation receivers that will allow satisfying the needs and the constraints of future application, presenting the main advantages given by the availability of a SDR navigation terminal. As example, the possibility to design an efficient M-code receiver (based on Binary Offset Carrier modulation – BOC) has been analyzed: on the basis of the Galileo SIS definition (Signal-In-Space), the SDR approach can be used in order to implement a modular structure compliant with an open system architecture concept, based upon high sampling rate Analog to Digital Converters (A/D), reconfigurable hardware (Field Programmable Gate Array - FPGA) and high speed Digital Signal Processors (DSP
Definizione dell'architettura di un ricevitore ibrido riconfigurabile per applicazioni di tipo NAV/COM
No full textMultivariate analysis of dilution-corrected residuals to improve the interpretation of geochemical anomalies and determine their potential sources: The Mingardo River case study (Southern Italy)
No full textStream sediment geochemical prospecting is historically acknowledged as a reliable tool to investigate the influence of geology and to assess the presence of natural and/or anthropogenic anomalies within river catchment basins at different scales. Several methods have been developed during decades to seek for geochemical anomalies especially those considered with a high potential for mineral resources. In the last decades, the Sample Catchment Basin (SCB) method, based on the use of dilution-corrected residuals (DCRs), has been developed, improved, and extensively used in mineral exploration, mostly at regional scale. In this paper the method was applied to a small catchment basin in southern Italy (Mingardo River) with the purposes of testing its reliability and improving the interpretation of geochemical patterns. The SCBs method was performed by using as input both unprocessed (raw) and centered log-ratio (clr) transformed data, and the obtained DCRs were classified through the concentration-area (C-A) method. After verifying the inadequacy of raw data, Principal component analysis (PCA) and Hierarchical Cluster Analysis (HCA) on PCA loadings were used to address and improve the interpretation processes in a multivariate perspective. The method has proved to be effective in identifying anomalies associated with lithological layers that are often not reported on the medium scale and which, however, have the ability to condition the geochemical patterns of the basin to which they belong. The geochemical footprint of anthropic presence (road, villages, etc.) was also detected although its impact on the study area is limited
REGAL: a Reconfigurable Receiver for GPS and Galileo
No full textIn this paper we described the software defined radio implementation of a receiver for GPS and Galileo system
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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