1,721,153 research outputs found
A Wavelet Based Neural Network Procedure for the Field Reconstruction of NMR Main Magnet
No full textA novel procedure to identify and correct the field inhomogeneities in Nuclear Magnetic Resonance (NMR) devices is proposed. Instead of local field measurements, the procedure makes only use of the information supplied by the standard output (absorption spectrum) of the device to determine the correction field to be supplied to the magnet. The reconstruction of the actual field map starting from the spectrum is carried out by means of a Neural Network (NN) approach. The inputs of NN are, in turn, the moments of the spectrum or a pattern of features extracted by a wavelet pre-processor. The accuracy achieved in correcting the field is acceptable and the computational burden of the operation phases appears to be smaller with respect to other methods. The nature and shape of the wavelets are particularly suitable for treating the asborption spectra signal. The procedure promises to be a possible alternative tool to the frequently needed routine calibrations of the magnetic field in Nuclear Magnetic Resonance devices
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
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