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        검색결과 2

        1.
        2014.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The New Vacuum Solar Telescope (NVST) is a 1-meter vacuum solar telescope that aims to observe the ne structures of active regions on the Sun. The main tasks of the NVST are high resolution imaging and spectral observations, including the measurements of the solar magnetic eld. The NVST has been collecting more than 20 million FITS les since it began routine observations in 2012 and produces a maximum observational records of 120 thousand les in a day. Given the large amount of les, the effective archiving and retrieval of les becomes a critical and urgent problem. In this study, we implement a new data archiving system for the NVST based on the Fastbit Not Only Structured Query Language (NoSQL) database. Comparing to the relational database (i.e., MySQL; My Structured Query Language), the Fastbit database manifests distinctive advantages on indexing and querying performance. In a large scale database of 40 million records, the multi- eld combined query response time of Fastbit database is about 15 times faster and fully meets the requirements of the NVST. Our study brings a new idea for massive astronomical data archiving and would contribute to the design of data management systems for other astronomical telescopes.
        4,000원
        2.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Inter-granular Bright Points (igBPs) are small-scale objects in the Solar photosphere which can be seen within dark inter-granular lanes. We present a new algorithm to automatically detect and extract igBPs. Laplacian and Morphological Dilation (LMD) technique is employed by the algorithm. It involves three basic processing steps: (1) obtaining candidate "seed" regions by Laplacian; (2) determining the boundary and size of igBPs by morphological dilation; (3) discarding brighter granules by a probability criterion. For validating our algorithm, we used the observed samples of the Dutch Open Telescope (DOT), collected on April 12, 2007. They contain 180 high-resolution images, and each has a 85×68arcsec2 85×68arcsec2 field of view (FOV). Two important results are obtained: first, the identified rate of igBPs reaches 95% and is higher than previous results; second, the diameter distribution is 220±25km 220±25km , which is fully consistent with previously published data. We conclude that the presented algorithm can detect and extract igBPs automatically and effectively.
        4,000원