49,372 research outputs found

    Multiple Depth DB Tables Indexing on the Sphere

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    Any project dealing with large astronomical datasets should consider the use of a relational database server (RDBS). Queries requiring quick selections on sky regions, objects cross-matching and other high-level data investigations involving sky coordinates could be unfeasible if tables are missing an effective indexing scheme. In this paper we present the Dynamic Index Facility (DIF) software package. By using the HTM and HEALPix sky pixelization schema, it allows a very efficient indexing and management of spherical data stored into MySQL tables. Any table hosting spherical coordinates can be automatically managed by DIF using any number of sky resolutions at the same time. DIF comprises a set of facilities among which SQL callable functions to perform queries on circular and rectangular regions. Moreover, by removing the limitations and difficulties of 2-d data indexing, DIF allows the full exploitation of the RDBS capabilities. Performance tests on Giga-entries tables are reported together with some practical usage of the package

    "Needless to Say My Proposal Was Turned Down": The Early Days of Commercial Citation Indexing, an "Error-making" Activity and Its Repercussions Till Today

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    In today’s neoliberal audit cultures university rankings, quantitative evaluation of publications by JIF or researchers by h-index are believed to be indispensable instruments for “quality assurance” in the sciences. Yet there is increasing resistance against “impactitis” and “evaluitis”. Usually overseen: Trivial errors in Thomson Reuters’ citation indexes produce severe non-trivial effects: Their victims are authors, institutions, journals with names beyond the ASCII-code and scholars of humanities and social sciences. Analysing the “Joshua Lederberg Papers” I want to illuminate eventually successful ‘invention’ of science citation indexing is a product of contingent factors. To overcome severe resistance Eugene Garfield, the “father” of citation indexing, had to foster overoptimistic attitudes and to downplay the severe problems connected to global and multidisciplinary citation indexing. The difficulties to handle different formats of references and footnotes, non-Anglo-American names, and of publications in non-English languages were known to the pioneers of citation indexing. Nowadays the huge for-profit North-American media corporation Thomson Reuters is the owner of the citation databases founded by Garfield. Thomson Reuters’ influence on funding decisions, individual careers, departments, universities, disciplines and countries is immense and ambivalent. Huge technological systems show a heavy inertness. This insight of technology studies is applicable to the large citation indexes by Thomson Reuters, too

    Fast algorithm for the 3-D DCT-II

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    Recently, many applications for three-dimensional (3-D) image and video compression have been proposed using 3-D discrete cosine transforms (3-D DCTs). Among different types of DCTs, the type-II DCT (DCT-II) is the most used. In order to use the 3-D DCTs in practical applications, fast 3-D algorithms are essential. Therefore, in this paper, the 3-D vector-radix decimation-in-frequency (3-D VR DIF) algorithm that calculates the 3-D DCT-II directly is introduced. The mathematical analysis and the implementation of the developed algorithm are presented, showing that this algorithm possesses a regular structure, can be implemented in-place for efficient use of memory, and is faster than the conventional row-column-frame (RCF) approach. Furthermore, an application of 3-D video compression-based 3-D DCT-II is implemented using the 3-D new algorithm. This has led to a substantial speed improvement for 3-D DCT-II-based compression systems and proved the validity of the developed algorithm

    Video databases annotation enhancing using commonsense knowledgebases for indexing and retrieval

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    The rapidly increasing amount of video collections, especially on the web, motivated the need for intelligent automated annotation tools for searching, rating, indexing and retrieval purposes. These videos collections contain all types of manually annotated videos. As this annotation is usually incomplete and uncertain and contains misspelling words, search using some keywords almost do retrieve only a portion of videos which actually contains the desired meaning. Hence, this annotation needs filtering, expanding and validating for better indexing and retrieval. In this paper, we present a novel framework for video annotation enhancement, based on merging two widely known commonsense knowledgebases, namely WordNet and ConceptNet. In addition to that, a comparison between these knowledgebases in video annotation domain is presented. Experiments were performed on random wide-domain video clips, from the \emph{vimeo.com} website. Results show that searching for a video over enhanced tags, based on our proposed framework, outperforms searching using the original tags. In addition to that, the annotation enhanced by our framework outperforms both those enhanced by WordNet and ConceptNet individually, in terms of tags enrichment ability, concept diversity and most importantly retrieval performance

    Automatic Annotation of Images from the Practitioner Perspective

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    This paper describes an ongoing project which seeks to contribute to a wider understanding of the realities of bridging the semantic gap in visual image retrieval. A comprehensive survey of the means by which real image retrieval transactions are realised is being undertaken. An image taxonomy has been developed, in order to provide a framework within which account may be taken of the plurality of image types, user needs and forms of textual metadata. Significant limitations exhibited by current automatic annotation techniques are discussed, and a possible way forward using ontologically supported automatic content annotation is briefly considered as a potential means of mitigating these limitations
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