Event Ontology In Coal Mining Safety Field And Its Application In Query Expansion

Coal mining accidents in our country occur currently, there is a large number of relevant reports, policies and measures on the Internet, which is redundant and complicated. Users often can’t get the results that they want in the retrieval process. Based on the characteristics of coal mine safety field, the paper uses event ontology technology to make domain information abstraction as domain knowledge, and puts forward query expansion method based event ontology, that implements the semantic retrieval and effectively improves the traditional search engine’s problem of recall and low precision, because it’s based on keyword matching principle.First, the paper analyses characteristics of coal mine safety field and finds that putting "concept" as a basic unit of ontology construction can’t accurately describe the domain knowledge because it’s lack of dynamic. Therefore, it is suggested that the event ontology concepts, and explains relevant technology.Secondly, the paper expounded the concept of event class, the relationships between event classes and event class properties, then proposed the concept of correlation factor between event class and its calculation method, which is used as a measure of association degree between event class. At last, event ontology model is proposed, which is laid the theoretical basis of constructing event ontology in coal mining safety field.Again, the paper put forward an ontology learning technology that treated field document as data source, including extracting event class in the document, a calculation method for the important degree of event class based on page link algorithm that is effective through an experiment. On the basis of above algorithm, we designed and implemented a important event class recommendation system. An experiment verified the feasibility of the ontology learning technique. Later, we select the owl ontology representation language and use the Protégé ontology editing tool to construct event ontology in the field of coal mining safety.Finally, we proposed a query extension method based on event ontology. First, we use word segmentation and dependency syntactic technology to analyze the query terms and extend event term in event and event’s properties, then use vector space model to vectoring the query terms and document and calculate similarity,get the output results.The query expansion method is feasible through an experiment.