I. Introduction
The emerging technology of human–computer interaction is widely used in companion robots [1], psychological disease diagnosis [2], intelligent teaching [3], etc. Considering its potential applications in which the machine triggers the corresponding response or operation by analyzing the user's affective, the sentiment analysis in human–computer interaction is increasingly receiving attention. Human can easily perceive other's sentiment in communication, which endows machines with the ability to perceive sentiment alike humans remains a research challenge.