Analyses of example sentences collected by conversation for example-based non-task-oriented dialog system

Designing an example database is important for handling various users' utterances in an example-based dialog system, and several approaches to constructing the database have been proposed. This paper focuses on a method for collecting the example sentences through actual conversations with the system. Several studies employ this approach for constructing the dialog system, but conventional research lacks attentive analyses. In this study, we analyzed how many examples can be collected from the interactions, and investigated the characteristics of the collected examples. The experimental results show that the response accuracy improved with the increase in number of the interactions, and the examined collection method is effective for collecting examples of consecutive utterances. In addition, subjective evaluation comparing the databases constructed using actual conversation and the fully-handcrafted databases was conducted through dialog experiments. The results showed that the examined approach can obtain higher subjective scores than the comparative approach in terms of user satisfaction, dialog engagement, intelligence, and intention of talking.