Labeling Results of Topic Models: Word Sense Disambiguation as Key Method for Automatic Topic Labeling with GermaNet

Abstract

The combination of topic modeling and automatic topic labeling sheds light on understanding large corpora of text. It can be used to add semantic information for existing metadata. In addition, one can use the documents and the corresponding topic labels for topic classification. While there are existing algorithms for topic modeling readily accessible for processing texts, there is a need to postprocess the result to make the topics more interpretable and self-explanatory. The topic words from the topic model are ranked and the first/top word could easily be considered as a label. However, it is imperative to use automatic topic labeling, because the highest scored word is not the word that sums up the topic in the best way. Using the lexical-semantic word net GermaNet, the first step is to disambiguate words that are represented in GermaNet with more than one sense. We show how to find the correct sense in the context of a topic with the method of word sense disambiguation. To enhance accuracy, we present a similarity measure based on vectors of topic words that considers semantic relations of the senses demonstrating superior performance of the investigated cases compared to existing methods.

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