检索结果-南通市图书馆

作者： Siti Nurul Rofiqo IRWAN Takeshi KINOSHITA Yoritaka TASHIRO Graduate School of Science and Technology Chiba UniversityJapan Faculty of Horticulture China UniversityJapan Faculty of Horticulture China UniversityJapan

＜正＞tree-shaded areas caused significantly cooling effect to support human activity in the tropics. The spatial variations of tree-shaded areas were classified into shade coverage of full shade （FS）, not-full shade （NFS） and no shade （NS）. This research aims to study the tree pattern of the tree-shaded areas in the green space of Yogyakarta, Indonesia and to analyze the relation to the spatial usage of human activity. The observation of human activity and interview were conducted to investigate the usage relation to tree pattern in tree-shaded areas. The six spots of observation were sketched and the tree patterns were analyzed. Human activities in the tree-shaded areas were movable in the morning and afternoon, and the tree-shaded area with full-shade was a centre of activity at noon. Canopy models of overlap-touch-spread and shade models of dark-slightly dark-light were considered to be a design concept for the tree-shaded areas of full shade-not full shade-no shade. The intensity of spatial usage of human activity in tree-shaded areas was identified in to intensive-semi intensive-not intensive.

关键词： tree-shaded Areas tree pattern Human activity Yogyakarta Indonesia

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HCH for Checking Containment of XPath Fragment

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Journal of Computer Science & Technology 2007年第5期22卷 736-748页

作者：冯建华廖雨果张勇 Department of Computer Science and Technology Tsinghua University Beijing 100084China

XPath is ubiquitous in XML applications for navigating XML trees and selecting a set of element nodes. In XPath query processing, one of the most important issues is how to efficiently check containment relationship between two XPath expressions. To get out of the intricacy and complexity caused by numerous XPath features, we investigate this issue on a frequently used fragment of XPath expressions that consists of node tests, the child axis （/）, the descendant axis （//）, branches （[]） and label wildcards （＊）. Prior work has shown that homomorphism technology can be used for containment checking. However, homomorphism is the sufficient but not necessary condition for containment. For special classes of this fragment, the homomorphism algorithm returns false negatives. To address this problem, this paper proposes two containment techniques, conditioned homomorphism and hidden conditioned homomorphism, and then presents sound algorithms for checking containment. Experimental results confirm the practicability and efficiency of the proposed algorithms.

关键词： computer software query containment conditioned homomorphism tree pattern XML XPath

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维普期刊数据库

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Path-partitioned encoding supports wildcard-awareness twig queries

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Journal of Shanghai University(English Edition) 2009年第5期13卷 363-374页

作者：徐小双冯玉才王锋 School of Computer Huazhong University of Science and Technology School of Computer Huanggang Normal University Technic Pre-research Department Dameng Database Company Limited

Finding all occurrences of a twig query in an XML database is a core operation for efficient evaluation of XML queries. It is important to effiectively handle twig queries with wildcards. In this paper, a novel path-partitioned encoding scheme is proposed for XML documents to capture paths of all elements, and a twig query is modeled as an Xpattern extended from tree pattern. After definition, simplification, normalization, verification and initialization of the Xpattern, both work sets and a join plan are generated. According to these measures, an effiective algorithm to answer for a twig query, called DMTwig, is designed without unnecessary elements and invalid structural joins. The algorithm can adaptively deal with twig queries with branch ([ ]), child edge (/), descendant edge (//), and wildcard (*) synthetically. We show that path-partitioned encoding scheme and Xpattern guarantee the I/O and CPU optimality for twig queries. Experiments on representative data set indicate that the proposed solution performs significantly.

关键词： XML tree pattern structural join encoding scheme twig query

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