**4.3. Semantic association layer**

The semantic association layer will mainly analyze the content and related characteristics of the data, using Jena as the core processing tool, based on the pre-built domain ontology model. The information in the citation knowledge base is marked by Jena and uses Jena for reasoning. Finally, the SPARQL language is used to retrieve the information that has been marked. The semantic layer is based on the user requirement ontology and the user database and implements user requirements through scenario reasoning.
