关键词: 语义相似度, 本体, 有向无环图

Abstract: Over the past few years, ontology-based semantic similarity has been widely used in many fields of information science. As such, methods for the calculation of semantic similarities from ontology have been receiving more and more attention. This paper analyzes principles, advantages, and disadvantages of existing methods for calculating semantic similarities, and it proposes a new method that assesses semantic similarity based on two properties of the Directed Acyclic Graph（DAG） structure of an ontology：the degree of overlap in paths from the root to the nodes corresponding to the given concepts and the depth of the Lowest Common Ancestor（LCA） node of these nodes. The proposed method is flexible and can be applied to ontologies of a wide variety of domains. It applies the proposed method to Gene Ontology（GO） and Plant Ontology（PO）, and it compares the results with those of two leading methods. Results show the correctness and effectiveness of the proposed method.

Key words: semantic similarity, ontology, directed acyclic graph