Abstract:

To improve the timeliness of detecting topics in retrospective topic detection, an improved locality sensitive Hashing (LSH) algorithm is proposed and applied in constructing hierarchical topic model for web news. Firstly, the news content feature is excavated, and the topic feature is excavated using latent dirichlet allocation model. Then the non-binary content eigenvector and topic eigenvector are converted to binary feature space. Finally, news articles are clustered in order using binary content eigenvector and binary topic eigenvector by LSH, and the hierarchical topic-content news topic model is generated. Experiments prove the following results: extracting content feature and topic feature can express the news exactly; converting content eigenvector and topic eigenvector to unified binary space can reduce the time complexity of clustering, and thus increase the efficiency of topic detection while ensure the accuracy and semantic expansibility.

Key words: topic detection, hierarchy clustering, topic model, locality sensitive Hashing