1,720,974 research outputs found
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
Two-dimensional TSVD resolution enhancement for EO applications
No full textA two-dimensional truncated singular value decomposition (TSVD) technique is proposed to enhance spatial resolution of earth observation (EO) products. The algorithm is based on the assumption that the gain function is a two-dimensional tensor product. Experiments under- taken on the data set of simulated two-dimensional radiometer measurements show the robustness of the technique and its effectiveness from a processing time viewpoint
A novel approach to Combretastatins: from trans epoxide to CA-4 and its dioxolane derivative
No full textVariations 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
2D TSVD to enhance the resolution of radiometer data
No full textA reconstruction technique based on the two-dimensional truncated singular value decomposition (TSVD) is first presented to enhance the spatial resolution of radiometer earth observation (EO) measurements. The technique is physically based on the assumption that the antenna gain function is separable. This hypothesis allows implementing a very computer time effective TSVD-based resolution enhancement technique. Experiments undertaken on a data set of both simulated and real two-dimensional radiometer measurements show a) the accurancy of the proposed approach, b) its robustness against the additive noise level, c) its effectiveness in terms of processing time
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
Landweber method in Hilbert and Banach spaces to reconstruct the NRCS field from GNSS-R measurements
No full textIn this study, reconstruction of the normalized radar cross-section (NRCS) image from noisy Global Navigation Satellite System Reflectometry (GNSS-R) Delay-Doppler Maps (DDMs) is addressed in both Hilbert and Banach spaces. The proposed approach, which is based on the Landweber regularization method, appropriately specialized to account for spatial invariance, is first developed in Hilbert space and then extended to the Banach space. The reconstruction performance of the methods is discussed using simulated DDMs and contrasted with a deconvolution technique based on constrained least squares (CLS). Experimental results demonstrate that the Landweber method in Banach space outperforms the Landweber method in Hilbert space and the CLS. In fact, these latter methods exhibit both over-smoothing and typical Gibbs-related oscillations. © 2014 Taylor & Francis
Two-dimensional TSVD to enhance the spatial resolution of radiometer data
No full textA reconstruction technique, based on the two-dimensional truncated singular value decomposition (TSVD), is first proposed to enhance the spatial resolution of radiometer earth observation (EO) measurements. The technique is very computer-time effective when the kernel is a two-dimensional tensor product. The key issue regarding the selection of the truncation parameter is addressed by the statistically-based Generalized Cross Validation (GCV) approach. Experiments undertaken on a data set consisting of both simulated and actual two-dimensional Special Sensor Microwave Imager (SSM/I) radiometer measurements show the robustness of the technique against the additive noise and its effectiveness in terms of processing time. A typical two-dimensional radiometer scene is processed in seconds by a standard PC processor
Two-dimensional TSVD resolution enhancement for EO applications
No full textA two-dimensional truncated singular value decomposition (TSVD) technique is rst proposed to enhance spatial resolution of earth observation (EO) products. The algorithm is based on the assumption that the gain function is a two-dimensional tensor product. Experiments undertaken on the data set of simulated two-dimensional radiometer measurements show the robustness of the technique and its eectiveness from a processing time viewpoint
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