In this paper, we present a technique for developing user simulators which are able to interact and evaluate conversational agents. Our technique is based on a statistical model that is automatically learned from a dialog corpus. This model is used by the user simulator to provide the following answer taking into account the complete history of the interaction. The main objective of our proposa...

The present study was conducted to investigate if and how conversational agent can facilitate explanation activity that is conducive to learning. This was investigated through two experiments where pairs of participants, who were enrolled in a psychology course, engaged in a task of explaining to their partners the meanings of concepts of technical terms taught in the course. During the task, t...

The present study investigates how a conversational agent can facilitate explanation activity. An experiment was conducted where pairs of participants, who were enrolled in a psychology course, engaged in a task of explaining to their partners the meanings of concepts of technical terms taught in the course. During the task, they interacted with a conversational agent, which was programmed to p...

In recent years there has been an increasing interest concerning the integration of speech and other communication media in conversational systems, originating the so-called multimodal conversational systems. When several interaction modalities are available, users can receive more feedback from a conversational system and it can also receive more information from users, leading to a reduction ...

Systems which automatically transcribe carefully dictated speech are now commercially available, but their performance degrades dramatically when the speaking style of users becomes more relaxed or conversational. This dissertation focuses on techniques that aim to improve the robustness of statistical speech transcription systems to conversational speaking styles. The dissertation shows first ...