关键词: 两阶段, 层次文本分类, 邻居辅助策略, 类别层次

Abstract: The traditional Two-stage Hierarchical Text Classification model（THTC model）is an effective method to solve the problem of large-scale hierarchical text classification, but it still suffers from low classification accuracy. To alleviate this problem, a new Two-stage Hierarchical Text Classification model based on Neighbor-Assistant strategy（THTC-NA model）is proposed. THTC-NA model consists of two stages: search and classification. In the search stage, the flat strategy is used to select the related categories for a given document from all leaf categories. The categories are ranked and the most related categories are taken as category candidates. Thus, a large-scale hierarchy is pruned into a much smaller but focused one. In the classification stage, the classification results of each candidate are computed by combining the results of ancestor categories and sibling categories of the candidate. Finally, the results of the search stage and the classification stage are fused together todetermine the target category for a given document. The experiments on the data set Newsgroups-18828 show that, compared with the THTC model, the THTC-NA model has a great help to improve the classification accuracy.

Key words: two-stage, hierarchical text classification, neighbor-assistant strategy, class hierarchy