The semantic inference exploits the stemming mechanism and ontology to explain and to represent the data of query sentences, as shown in Fig. 2.
Preprocess:
Preprocess translates the various query sentences to form a vector space model. In the training stage, the query sentences are based on the selected questions because a set of documents can be presented by a word-by-document matrix P, as shown in Eq. (1). Moreover, each query sentence corresponds to one selected question Let W be the number of occurrences of all the words in the user questions, and Q be the number of occurrences of all the collected query sentences.