针对现有XML文档结构相似性度量方法大多不能完全反映XML文档的结构特征,相似度计算结果精确度不高,导致聚类效果不够理想的问题,提出一种改进的相似度计算方法 SSPF(Similarity based on Sequence,Position and Frequency)。该方法充...针对现有XML文档结构相似性度量方法大多不能完全反映XML文档的结构特征,相似度计算结果精确度不高,导致聚类效果不够理想的问题,提出一种改进的相似度计算方法 SSPF(Similarity based on Sequence,Position and Frequency)。该方法充分利用提取的DOM树路径信息,对树路径间序列和位置的相似度计算进行优化,并考虑了路径频率对相似度的影响,使得文档间的相似性更为合理。实验结果表明,SSPF方法具有更加准确的相似度计算结果,聚类的各项评价指标均有所提高。展开更多
Novel syndiotactic polystyrene/montmorillonite nanocomposites were prepared via in situ intercalative coordination polymerization with Cp *Ti(OBz) 3/MTN/MAO/TIBA catalytic system. The effect of polymerization conditio...Novel syndiotactic polystyrene/montmorillonite nanocomposites were prepared via in situ intercalative coordination polymerization with Cp *Ti(OBz) 3/MTN/MAO/TIBA catalytic system. The effect of polymerization conditions such as MTN/St mass ratio, temperature and monomer concentration on the styrene syndiospecific polymerization was investigated. The intercalation spacing in the nanocomposites as well as the exfoliation of the layer host was characterized with wide angle X-ray diffraction and transmission electron microscopy. The dispersibility of the nanoscale elemnets depended on the polymerization conditions and whether a surfactant is added or not into the montmorillonite.展开更多
文摘针对现有XML文档结构相似性度量方法大多不能完全反映XML文档的结构特征,相似度计算结果精确度不高,导致聚类效果不够理想的问题,提出一种改进的相似度计算方法 SSPF(Similarity based on Sequence,Position and Frequency)。该方法充分利用提取的DOM树路径信息,对树路径间序列和位置的相似度计算进行优化,并考虑了路径频率对相似度的影响,使得文档间的相似性更为合理。实验结果表明,SSPF方法具有更加准确的相似度计算结果,聚类的各项评价指标均有所提高。
文摘Novel syndiotactic polystyrene/montmorillonite nanocomposites were prepared via in situ intercalative coordination polymerization with Cp *Ti(OBz) 3/MTN/MAO/TIBA catalytic system. The effect of polymerization conditions such as MTN/St mass ratio, temperature and monomer concentration on the styrene syndiospecific polymerization was investigated. The intercalation spacing in the nanocomposites as well as the exfoliation of the layer host was characterized with wide angle X-ray diffraction and transmission electron microscopy. The dispersibility of the nanoscale elemnets depended on the polymerization conditions and whether a surfactant is added or not into the montmorillonite.