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A Comparative Study on Two Techniques of Reducing the Dimension of Text Feature Space
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作者 Yin Zhonghang, Wang Yongcheng, Cai Wei & Diao Qian School of Electronic & Information Technology, Shanghai Jiaotong University, Shanghai 200030, P.R.China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2002年第1期87-92,共6页
With the development of large scale text processing, the dimension of text feature space has become larger and larger, which has added a lot of difficulties to natural language processing. How to reduce the dimension... With the development of large scale text processing, the dimension of text feature space has become larger and larger, which has added a lot of difficulties to natural language processing. How to reduce the dimension has become a practical problem in the field. Here we present two clustering methods, i.e. concept association and concept abstract, to achieve the goal. The first refers to the keyword clustering based on the co occurrence of 展开更多
关键词 in the same text and the second refers to that in the same category. Then we compare the difference between them. Our experiment results show that they are efficient to reduce the dimension of text feature space. Keywords: Text data mining
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Mass transfer mechanisms in fixed-bed adsorption of erythromycin 被引量:2
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作者 Ying SUN Jiawen ZHU +2 位作者 Kui CHEN Sheng ZHU Jie XU 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2008年第4期353-360,共8页
The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performa... The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients. 展开更多
关键词 fixed-bed adsorption superficial velocity ionic strength erythromycin However investigations on the parameters governing the performance of this technology are still scarce.In the present work a polymeric and porous resin Sepabeads SP825 resin was used for its higher adsorption efficiency compared with the resins reported.The equilib-rium capacity of Sepabeads SP825 for EM in a batch system was established using a Langmuir isotherm.The effects of superficial velocity ionic strength and pH on the adsorption process were determined from the results of fixed bed experiments.And a model of the purification process was used to simulate the mass transfer mechanism which has taken film mass transfer pore diffusion and axial dispersion into account.The experimental adsorp-tion measurements were compared to the results calcu-lated from the model.The completion of these studies provide some essential parameters which are required in order to design a successful purification process and better understand the fundamentals of these process.
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