Zhang Yibo

PM-based indexing for Chinese text retrieval

This paper focused on introducing a novel PM indexing schema for Chinese text retrieval. Different with the Western languages, there is no delimiter between words in Chinese texts. The indexing is based either on the characters or on the segmented words. For the word-based indexing, the out-of-vocabulary words, such as the proper nouns, or domain terminology, are usually mis-segmented due to the limited vocabulary coverage of the segmentation dictionaries and thus impair the query precision. In this paper, several indexing and ranking methods, including the novel PM-based ranking, were tested so as to compare their efficiency in dealing with the new words in Chinese text retrieval. The experiment has shown that the query precision of the PM + word method is 10% higher than the word indexing.This paper focused on introducing a novel PM indexing schema for Chinese text retrieval. Different with the Western languages, there is no delimiter between words in Chinese texts. The indexing is based either on the characters or on the segmented words. For the word-based indexing, the out-of-vocabulary words, such as the proper nouns, or domain terminology, are usually mis-segmented due to the limited vocabulary coverage of the segmentation dictionaries and thus impair the query precision. In this paper, several indexing and ranking methods, including the novel PM-based ranking, were tested so as to compare their efficiency in dealing with the new words in Chinese text retrieval. The experiment has shown that the query precision of the PM + word method is 10% higher than the word indexing.

A Novel Nano-sized Catalyst CeO 2 -CuO/Hollow ZSM-5 for NO x Reduction with NH 3

Hollow-ZSM-5 was synthesized by a traditional hydrothermal method without alcohol, and a novel na-no-sized Ce-Cu/hollow ZSM-5 sample was prepared by conventional incipient wetness impreganation. The catalysts were characterized by TEM, SEM, XRD, NMR and N2 adsorption-desorption. The results indicate that the hollow-ZSM-5 has a good MFI structure with large surface area. The synthesized CeO2-CuO/hollow ZSM-5 showed an excellent catalytic activity for NOx conversion(90% NOx conversion were obtained) in the temperature range of 340–550 °C under GHSV=480000 mL·g‒1·h‒1 due to its appropriate redox ability and acidity.

The application of the comparable corpora in Chinese-English cross-lingual information retrieval

This paper proposes a novel Chinese-English Cross-Lingual Information Retrieval (CECLIR) model PME, in which bilingual dictionary and comparable corpora are used to translate the query terms. The proximity and mutual information of the term-pairs in the Chinese and English comparable corpora are employed not only to resolve the translation ambiguities but also to perform the query expansion so as to deal with the out-of-vocabulary issues in the CECLIR. The evaluation results show that the query precision of PME algorithm is about 84.4% of the monolingual information retrieval.This paper proposes a novel Chinese-English Cross-Lingual Information Retrieval (CECLIR) model PME, in which bilingual dictionary and comparable corpora are used to translate the query terms. The proximity and mutual information of the term-pairs in the Chinese and English comparable corpora are employed not only to resolve the translation ambiguities but also to perform the query expansion so as to deal with the out-of-vocabulary issues in the CECLIR. The evaluation results show that the query precision of PME algorithm is about 84.4% of the monolingual information retrieval.