Hybrid Dialogue State Tracking for Real World Human-to-Human Dialogues

Dialogue state tracking is a key sub-task of dialogue management. The fourth Dialog State Tracking Challenge (DSTC-4) focuses on dialogue state tracking for real world human-to-human dialogues. The task is more challenging than previous challenges because of more complex domain and coreferences, more synonyms and abbreviations, sub-dialogue level labelled utterances, and no spoken language understanding output provided. To deal with these challenges, this paper proposes a novel hybrid dialogue state tracking method, which can take advantage of the strength of both rule-based and statistical methods. Thousands of rules are first automatically generated using a template-based rule generation approach and then combined together with several manually designed rules to yield the output of the rule-based method. In parallel, a statistical method is applied to track the state. The tracker finally takes the union of the outputs of the two methods. In DSTC-4 evaluation, the proposed hybrid tracker obtained state-of-the-art results. It ranked the second and significantly outperformed the baseline system and most submissions.