Miscommunication handling in spoken dialog systems based on error-aware dialog state detection

With the exponential growth in computing power and progress in speech recognition technology, spoken dialog systems (SDSs) with which a user interacts through natural speech has been widely used in human-computer interaction. However, error-prone automatic speech recognition (ASR) results usually lead to inappropriate semantic interpretation so that miscommunication happens easily. This paper presents an approach to error-aware dialog state (DS) detection for robust miscommunication handling in an SDS. Non-understanding (Non-U) and misunderstanding (Mis-U) are considered for miscommunication handling in this study. First, understanding evidence (UE), derived from the recognition confidence, is adopted for Non-U detection followed by Non-U recovery. For Mis-U with the recognized sentence containing uncertain recognized words, the partial sentences obtained by removing potentially misrecognized words from the input utterance are organized, based on regular expressions, as a tree structure to tolerate the deletion or rejection of keywords resulting from misrecognition for Mis-U DS modeling. Latent semantic analysis is then employed to consider the verified words and their n-grams for DS detection, including Mis-U and predefined Base DSs. Historical information-based n-grams are employed to find the most likely DS for the SDS. Several experiments were performed with a dialog corpus for the restaurant reservation task. The experimental results show that the proposed approach achieved a promising performance for Non-U recovery and Mis-U repair as well as a satisfactory task success rate for the dialogs using the proposed method.