The inspiration is that, in researches of word embeddings: (i) The word vectors are asked to contribute to a prediction task about the target word or the surrounding words in the context; (ii) The word representation vectors are initialized randomly, however they could finally capture precise semantics as an indirect result.
we will utilize this idea in our sentence vectors in a similar manner: The conceptassociated sentence vectors are also asked to contribute to the prediction task of the target word or surrounding words in given contextual text windows.