1,720,982 research outputs found
Retinex preprocessing of uncalibrated images for color based image retrieval
No full textIn image databases, variations in imaging conditions and preprocessing may result in similar originals that exhibit a low measure of similarity when color information is used in standard image retrieval methods. We examine the performance of various color-based retrieval strategies to see whether, and to what degree, the effectiveness of retrieval improves with Retinex-based preprocessing, regardless of the strategy adopted. The results of experiments performed on four different databases are reported and discussed
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
Controlled and uncontrolled viewing conditions in the evaluation of prints
No full textVisual experiments, attesting visual preference, visual ranking and visual differentiation, are very important to academia and industry. They are traditionally performed into laboratories under controlled viewing conditions, resulting very costly in their execution, due to the time and effort involved by all participants. If controlled tests could be substituted by uncontrolled tests, a potential serious improvement could be obtained by eliminating a large part of the cost. In this work we investigate if, and to what extent, visual experiments performed under controlled viewing conditions can be substituted by uncontrolled experiments. A task of visual preference of prints is carried out. This task is performed in the laboratory, under controlled viewing conditions, and in many different places, under natural, artificial and mixed light. We observe statistical equivalence for preferences expressed in controlled or uncontrolled conditions that supports the hypothesis that visual preference can be assessed with uncontrolled tests
A study on the equivalence of controlled and uncontrolled visual experiments
No full textVisual experiments, if performed in a traditional way, require asking participants to go to a laboratory, where displays are calibrated and illumination conditions are set in a convenient way. In recent years there has been an increasing interest in performing the experiments "out of the lab", with the aim of reducing costs, increasing the number of participants, and differentiating the population. The equivalence of the response of visual experiments performed in controlled and uncontrolled contexts is an open question which calls for research. In this work we aim at analyzing more deeply the equivalence between "controlled" and "uncontrolled" that we found in a previous study of the authors on the comparison of visual preferences for printed images. In particular, we are interested in understanding if, and to what degree, the uncontrolled experiments require actually more participants in order to average out the effects of the many uncontrolled parameters which may affects the response. In addition we aim at exploring the relationship, if any, between our previous conclusions and the difference in the attributes of the images for which the observers were asked to express their preference
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