1,721,105 research outputs found
GeoAI as Collaborative Effort: Interview with Devis Tuia
Full text linkDevis Tuia is an Associate Professor at Ecole Polytechnique Fédérale de Lausanne (EPFL), where he heads the Environmental Computational Science and Earth Observation (ECEO) laboratory. Devis is an expert in earth observation and remote sensing research, machine learning, and image processing. His current work includes interpretable deep learning in environmental modeling, human-machine interaction in remote sensing, and digital wildlife conservation, i.e., using imaging to automatize censuses and conservation efforts
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
Passive Optical Data Processing
No full textThis chapter introduces a series of techniques specific to the processing of passive optical images, e.g. multi- and hyperspectral images. The following operations are studied: (1) merging panchromatic images with multispectral images (or pansharpening), (2) extracting indices specific to a given application and (3) extracting two types of products - land use maps and subpixel mixture maps. The chapter explains two families of texture indices: the occurrence indices and the co-occurrence indices. The occurrence indices are calculated directly on the values of the pixels composing the moving window around the pixel considered. Co-occurrence considers the spatial information between pairs of pixels in a given window. Two families of geometrical indices of surfaces are considered: those resulting from mathematical morphology and those based on attribute profiles. The chapter talks about the classification maps and the subpixel mixture maps.</p
ENSEMBLE METHODS FOR ENVIRONMENTAL DATA MODELLING WITH SUPPORT VECTOR REGRESSION 15TH European Colloquium on Theoretical and Quantitative Geography
No full textThis paper investigates the use of ensemble of predictors in order to improve the performance of spatial prediction methods. Support vector regression (SVR), a popular method from the field of statistical machine learning, is used. Several instances of SVR are combined using different data sampling schemes (bagging and boosting). Bagging shows good performance, and proves to be more computationally efficient than training a single SVR model while reducing error. Boosting, however, does not improve results on this specific problem
Weakly Supervised Alignment Of Image Manifolds With Semantic Ties
No full textAligning data distributions that underwent spectral distortions related to acquisition conditions is a key issue to improve the performance of classifiers applied to multi-temporal and multi-angular images. In this paper, we propose a feature extraction methodology, which aligns data manifolds based on their internal geometric structure and on a series of object correspondences highlighted on each image, or tie points. The weakly supervised manifold alignment (WeSMA) is a feature extractor that allows to define a common latent space, in which the images can be projected and processed by the same classifier. WeSMA relaxes the need for labeled pixels in all acquisitions of previous manifold alignment methods, an heavy constraint for remote sensing applications. Experiments on a set of World-View II images acquired at different viewing angles show the interest of the method that can compensate the spectral shift generated by the angular distortion without labels issued from the off-nadir image.LASI
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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