Browsing by Author "Huang, Yu-Siang"

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Extracting semantic relations to enrich domain ontologies
(2012-12-01)
Shen, Minxin
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Liu, Duen-Ren
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Huang, Yu-Siang
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資訊管理與財務金融系註：原資管所+財金所
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Department of Information Management and Finance
Domain ontologies facilitate the organization, sharing and reuse of domain knowledge, and enable various vertical domain applications to operate successfully. Most methods for automatically constructing ontologies focus on taxonomic relations, such as is-kind-of and is-part-of relations. However, much of the domain-specific semantics is ignored. This work proposes a semi-unsupervised approach for extracting semantic relations from domain-specific text documents. The approach effectively utilizes text mining and existing taxonomic relations in domain ontologies to discover candidate keywords that can represent semantic relations. A preliminary experiment on the natural science domain (Taiwan K9 education) indicates that the proposed method yields valuable recommendations. This work enriches domain ontologies by adding distilled semantics.
Reversible Cleavage/Formation of the Chromium-Chromium Quintuple Bond in the Highly Regioselective Alkyne Cyclotrimerization
(2017-11-27)
Huang, Yu-Siang
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Huang, Gou-Tao
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Liu, Yao-Lun
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Yu, Jen-Shiang K.
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Tsai, Yi-Chou
Herein we report the employment of the quintuply bonded dichromium amidinates [Cr{(2)-HC(N-2,6-(Pr2C6H3)-Pr-i)(N-2,6-R2C6H3)}](2) (R=iPr (1), Me (7)) as catalysts to mediate the [2+2+2] cyclotrimerization of terminal alkynes giving 1,3,5-trisubstituted benzenes. During the catalysis, the ultrashort Cr-Cr quintuple bond underwent reversible cleavage/formation, corroborated by the characterization of two inverted arene sandwich dichromium complexes (-(6):(6)-1,3,5-(Me3Si)(3)C6H3)[Cr{(2)-HC(N-2,6-(Pr2C6H3)-Pr-i)(N-2,6-R2C6H3)}](2) (R=Pr-i (5), Me (8)). In the presence of sigma donors, such as THF and 2,4,6-Me3C6H2CN, the bridging arene 1,3,5-(Me3Si)(3)C6H3 in 5 and 8 was extruded and 1 and 7 were regenerated. Theoretical calculations were employed to disclose the reaction pathways of these highly regioselective [2+2+2] cylcotrimerization reactions of terminal alkynes.