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A New Mechanism Based on Similar Clouds Watermark for Database’s Information Security 被引量:4
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作者 HUANGMin CAOJia-heng +1 位作者 PENGZhi-yong ZENGCheng 《Wuhan University Journal of Natural Sciences》 CAS 2004年第4期415-419,共5页
This paper studies the digit watermark technology of numeric attributes in relational database for database's information security. It proposes a new mechanism based on similar clouds watermark and gives the conce... This paper studies the digit watermark technology of numeric attributes in relational database for database's information security. It proposes a new mechanism based on similar clouds watermark and gives the concept of similar clouds. The algorithm SCWA that can insert the meaning watermark and detect it from the watermarked data is described. The mechanism can effectively and broadly scatter the watermark in the database; therefore the watermark is very robust. Key words copyright protection - digit watermark - similar clouds - clouds model CLC number TP 311. 52 Foundation item: Supported by the National Natural Science Foundation of China (60273072) and 863 Hi-technique Research (2002AA4Z3450)Biography: HUANG Min(1979-), female, Ph. D candidate, research direction: database's information security 展开更多
关键词 copyright protection digit watermark similar clouds clouds model
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Web Fuzzy Clustering and a Case Study
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作者 LIUMao-fu HEJing +1 位作者 HEYan-xiang HUHui-jun 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第4期411-414,共4页
We combine the web usage mining and fuzzy clustering and give the concept of web fuzzy clustering, and then put forward the web fuzzy clustering processing model which is discussed in detail. Web fuzzy clustering can ... We combine the web usage mining and fuzzy clustering and give the concept of web fuzzy clustering, and then put forward the web fuzzy clustering processing model which is discussed in detail. Web fuzzy clustering can be used in the web users clustering and web pages clustering. In the end, a case study is given and the result has proved the feasibility of using web fuzzy clustering in web pages clustering. Key words web mining - web usage mining - web fuzzy clustering - WFCM CLC number TP 391 Foundation item: Supported by the National Natural Science Foundation of China (90104005)Biography: LIU Mao-fu (1977-), male, Ph. D candidate, research direction: artificial intelligence, web mining, image mining. 展开更多
关键词 web mining web usage mining web fuzzy clustering WFCM
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A Direct Parameter-Extraction Method for GaInP/GaAs Heterojunction Bipolar Transistors Small-Signal Model
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作者 SHIXin-zhi LIUHai-wen +3 位作者 SUNXiao-wei CHEYan-feng CHENGZhi-qun LIZheng-fan 《Wuhan University Journal of Natural Sciences》 CAS 2005年第2期405-409,共5页
An accurate and broad-band method for hetero-junction bipolar transistors(HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit forthe HBT under a forward-bias condition is pr... An accurate and broad-band method for hetero-junction bipolar transistors(HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit forthe HBT under a forward-bias condition is proposed for extraction of accessresistance and parasiticinductance. This method differs from previous ones by extracting the c-quivalent circuit parameterswithout using special test structure or global numerical optimization techniques. The mainadvantage of this method is that a unique and physically meaningful set of intrinsic parameters isextracted from impedance and admittance representation of the measured S-pa-rameters in thefrequency range of 1-12 GHz under different bias conditions. The method yields a deviation of lessthan 5% between measured and modeled S-parameters. 展开更多
关键词 GalnP/GaAs HBT parameter extraction small-signal model
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