161 research outputs found

    On Multistage Learning a Hidden Hypergraph

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    Learning a hidden hypergraph is a natural generalization of the classical group testing problem that consists in detecting unknown hypergraph Hun=H(V,E)H_{un}=H(V,E) by carrying out edge-detecting tests. In the given paper we focus our attention only on a specific family F(t,s,)F(t,s,\ell) of localized hypergraphs for which the total number of vertices V=t|V| = t, the number of edges Es|E|\le s, sts\ll t, and the cardinality of any edge e|e|\le\ell, t\ell\ll t. Our goal is to identify all edges of HunF(t,s,)H_{un}\in F(t,s,\ell) by using the minimal number of tests. We develop an adaptive algorithm that matches the information theory bound, i.e., the total number of tests of the algorithm in the worst case is at most slog2t(1+o(1))s\ell\log_2 t(1+o(1)). We also discuss a probabilistic generalization of the problem.Comment: 5 pages, IEEE conferenc

    Collapse of the critical state in superconducting niobium

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    Giant abrupt changes in the magnetic flux distribution in niobium foils were studied by using magneto-optical visualization, thermal and magnetic measurements. Uniform flux jumps and sometimes almost total catastrophic collapse of the critical state are reported. Results are discussed in terms of thermomagnetic instability mechanism with different development scenarios.Comment: arXiv.org produced artifacts in color images (three versions were attempts to make better images). Download clean PDF and watch video-figures at: "http://cmp.ameslab.gov/supermaglab/video/Nb.html

    Preparation of microscaner data and core photos for joint analysis and linking

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    Correlation Optics

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