1,721,066 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Evaluation du potentiel de la technique PolInSAR pour l'estimation des paramètres physiques de la végétation en conditions satellitaires
No full textThe goal of this work has been the evaluation of PolInSAR technique potential for the extraction of forest physical parameters and the transposition of such analysis to spatial conditions.Previous works have shown that PolInSAR technique presents a good potential for tree height inversion, which can be linked to the above ground biomass through allometric relation, using L-band data. The first part of this work has consisted in the inversion procedure adaptation to extreme frequencies of the spectra which is generally used for natural surfaces investigation, X- and P-band, using data acquired over pine forests by RAMSES airborne system.Then, influence of the most variable system parameters from airborne to spaceborne conditions, as resolution and Signal-to-Noise ratio, is evaluated on the inversion robustness and accuracy at X-, L- and P-bands, in order to determine its limitations in spaceborne conditions.L'objectif de ce travail de thèse a été d'évaluer le potentiel de la technique PolInSAR pour l'extraction des paramètres physiques de la forêt et la transposition de ce type d'analyse aux conditions spatiales. Des travaux antérieurs ont montré que cette technique était efficace pour l'estimation de la hauteur des arbres, qui peut être reliée à la biomasse aérienne par une relation allométrique, à partir de données acquises en bande L. La première partie de ces travaux a porté sur le développement de procédures d'inversions aux fréquences extrêmes du spectre généralement utilisé pour l'étude des surfaces naturelles, la bande X et la bande P, dans le contexte de données acquises par le système aéroporté RAMSES sur des forêts de pins. Ensuite, l'influence des paramètres système qui diffèrent le plus de l'aéroporté au satellitaire, la résolution et le rapport Signal à Bruit, est quantifiée sur la robustesse et la précision de l'inversion en bandes X, L et P afin d'en déterminer les limitations en conditions spatiales
Evaluation du potentiel de la technique PolInSAR pour l'estimation dse paramètres physiques de la végétation en conditions satellitaires
Get PDFL'objectif de ce travail de thèse a été d'évaluer le potentiel de la technique PolInSAR pour l'extraction des paramètres physiques de la forêt et la transposition de ce type d'analyse aux conditions spatiales. Des travaux antérieurs ont montré que cette technique était efficace pour l'estimation de la hauteur des arbres, qui peut êetre reliée à la biomasse aérienne par une relation allométrique, à partir de données acquises en bande L. La première partie de ces travaux a porté sur le développement de procédures d'inversions aux fréquences extrêemes du spectre généralement utilis é pour l'étude des surfaces naturelles, la bande X et la bande P, dans le contexte de données acquises par le système aéroporté RAMSES sur des forêts de pins. Ensuite, l'influence des paramètres système qui diffèrent le plus de l'aéroporté au satellitaire, la résolution et le rapport Signal à Bruit, est quantifiée sur la robustesse et la précision de l'inversion en bandes X, L et P afin d'en déterminer les limitations en conditions spatiales.The goal of this work has been the evaluation of PolInSAR technique potential for the extraction of forest physical parameters and the transposition of such analysis to spatial conditions. Previous works have shown that PolInSAR technique presents a good potential for tree height inversion, which can be linked to the above ground biomass through allometric relation, using L-band data. The first part of this work has consisted in the inversion procedure adaptation to extreme frequencies of the spectra which is generally used for natural surfaces investigation, Xand P-band, using data acquired over pine forests by RAMSES airborne system. Then, influence of the most variable system parameters from airborne to spaceborne conditions, as resolution and Signal-to-Noise ratio, is evaluated on the inversion robustness and accuracy at X-, L- and P-bands, in order to determine its limitations in spaceborne conditions
Variations on the Author
Get PDF“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
Evaluation du potentiel de la technique PolInSAR pour l'estimation des paramètres physiques de la végétation en conditions satellitaires
No full textThe goal of this work has been the evaluation of PolInSAR technique potential for the extraction of forest physical parameters and the transposition of such analysis to spatial conditions.Previous works have shown that PolInSAR technique presents a good potential for tree height inversion, which can be linked to the above ground biomass through allometric relation, using L-band data. The first part of this work has consisted in the inversion procedure adaptation to extreme frequencies of the spectra which is generally used for natural surfaces investigation, X- and P-band, using data acquired over pine forests by RAMSES airborne system.Then, influence of the most variable system parameters from airborne to spaceborne conditions, as resolution and Signal-to-Noise ratio, is evaluated on the inversion robustness and accuracy at X-, L- and P-bands, in order to determine its limitations in spaceborne conditions.L'objectif de ce travail de thèse a été d'évaluer le potentiel de la technique PolInSAR pour l'extraction des paramètres physiques de la forêt et la transposition de ce type d'analyse aux conditions spatiales. Des travaux antérieurs ont montré que cette technique était efficace pour l'estimation de la hauteur des arbres, qui peut être reliée à la biomasse aérienne par une relation allométrique, à partir de données acquises en bande L. La première partie de ces travaux a porté sur le développement de procédures d'inversions aux fréquences extrêmes du spectre généralement utilisé pour l'étude des surfaces naturelles, la bande X et la bande P, dans le contexte de données acquises par le système aéroporté RAMSES sur des forêts de pins. Ensuite, l'influence des paramètres système qui diffèrent le plus de l'aéroporté au satellitaire, la résolution et le rapport Signal à Bruit, est quantifiée sur la robustesse et la précision de l'inversion en bandes X, L et P afin d'en déterminer les limitations en conditions spatiales
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
PolInSAR technique potential evaluation for vegetation physical parameter estimation in spatial conditions
No full textL'objectif de ce travail de thèse a été d'évaluer le potentiel de la technique PolInSAR pour l'extraction des paramètres physiques de la forêt et la transposition de ce type d'analyse aux conditions spatiales. Des travaux antérieurs ont montré que cette technique était efficace pour l'estimation de la hauteur des arbres, qui peut être reliée à la biomasse aérienne par une relation allométrique, à partir de données acquises en bande L. La première partie de ces travaux a porté sur le développement de procédures d'inversions aux fréquences extrêmes du spectre généralement utilisé pour l'étude des surfaces naturelles, la bande X et la bande P, dans le contexte de données acquises par le système aéroporté RAMSES sur des forêts de pins. Ensuite, l'influence des paramètres système qui diffèrent le plus de l'aéroporté au satellitaire, la résolution et le rapport Signal à Bruit, est quantifiée sur la robustesse et la précision de l'inversion en bandes X, L et P afin d'en déterminer les limitations en conditions spatiales.The goal of this work has been the evaluation of PolInSAR technique potential for the extraction of forest physical parameters and the transposition of such analysis to spatial conditions.Previous works have shown that PolInSAR technique presents a good potential for tree height inversion, which can be linked to the above ground biomass through allometric relation, using L-band data. The first part of this work has consisted in the inversion procedure adaptation to extreme frequencies of the spectra which is generally used for natural surfaces investigation, X- and P-band, using data acquired over pine forests by RAMSES airborne system.Then, influence of the most variable system parameters from airborne to spaceborne conditions, as resolution and Signal-to-Noise ratio, is evaluated on the inversion robustness and accuracy at X-, L- and P-bands, in order to determine its limitations in spaceborne conditions
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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