513,915 research outputs found

    Artequakt: Generating tailored biographies from automatically annotated fragments from the web

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    The Artequakt project seeks to automatically generate narrativebiographies of artists from knowledge that has been extracted from the Web and maintained in a knowledge base. An overview of the system architecture is presented here and the three key components of that architecture are explained in detail, namely knowledge extraction, information management and biography construction. Conclusions are drawn from the initial experiences of the project and future progress is detailed

    Photon Structure Function

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    After briefly explaining the idea of photon structure functions (\f2gam\ , \flgam) I review the current theoretical and experimental developements in the subject of extraction of \qvph\ from a study of the Deep Inelastic Scattering (DIS). I then end by pointing out recent progress in getting information about the parton content of the photon from hard processes other than DIS.Comment: 14 pages, 6 postscript figures, latex, uses equation.sty and epsfig.sty .sty files not adde

    Randomized Dimensionality Reduction for k-means Clustering

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    We study the topic of dimensionality reduction for kk-means clustering. Dimensionality reduction encompasses the union of two approaches: \emph{feature selection} and \emph{feature extraction}. A feature selection based algorithm for kk-means clustering selects a small subset of the input features and then applies kk-means clustering on the selected features. A feature extraction based algorithm for kk-means clustering constructs a small set of new artificial features and then applies kk-means clustering on the constructed features. Despite the significance of kk-means clustering as well as the wealth of heuristic methods addressing it, provably accurate feature selection methods for kk-means clustering are not known. On the other hand, two provably accurate feature extraction methods for kk-means clustering are known in the literature; one is based on random projections and the other is based on the singular value decomposition (SVD). This paper makes further progress towards a better understanding of dimensionality reduction for kk-means clustering. Namely, we present the first provably accurate feature selection method for kk-means clustering and, in addition, we present two feature extraction methods. The first feature extraction method is based on random projections and it improves upon the existing results in terms of time complexity and number of features needed to be extracted. The second feature extraction method is based on fast approximate SVD factorizations and it also improves upon the existing results in terms of time complexity. The proposed algorithms are randomized and provide constant-factor approximation guarantees with respect to the optimal kk-means objective value.Comment: IEEE Transactions on Information Theory, to appea

    Investigation related to multispectral imaging systems

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    A summary of technical progress made during a five year research program directed toward the development of operational information systems based on multispectral sensing and the use of these systems in earth-resource survey applications is presented. Efforts were undertaken during this program to: (1) improve the basic understanding of the many facets of multispectral remote sensing, (2) develop methods for improving the accuracy of information generated by remote sensing systems, (3) improve the efficiency of data processing and information extraction techniques to enhance the cost-effectiveness of remote sensing systems, (4) investigate additional problems having potential remote sensing solutions, and (5) apply the existing and developing technology for specific users and document and transfer that technology to the remote sensing community

    Cosmic X-ray physics

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    The soft X-ray sky survey data are combined with the results from the UXT sounding rocket payload. Very strong constraints can then be placed on models of the origin of the soft diffuse background. Additional observational constraints force more complicated and realistic models. Significant progress was made in the extraction of more detailed spectral information from the UXT data set. Work was begun on a second generation proportional counter response model. The first flight of the sounding rocket will have a collimator to study the diffuse background
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