We previously introduced a responsive joint attention system that uses multimodal information from users engaged in a spatial reasoning task with a robot and communicates joint attention via the robot's gaze behavior. An initial evaluation of our system with adults showed it to improve users' perceptions of the robot's social presence. To investigate the repeatability of our prior findings across settings and populations, here we conducted two further studies employing the same gaze system with the same robot and task but in different contexts: evaluation of the system with external observers and evaluation with children. The external observer study suggests that third-person perspectives over videos of gaze manipulations can be used either as a manipulation check before committing to costly real-time experiments or to further establish previous findings. However, the replication of our original adults study with children in school did not confirm the effectiveness of our gaze manipulation, suggesting that different interaction contexts can affect the generalizability of results in human-robot interaction gaze studies.

Traditionally, subjective text-To-speech (TTS) evaluation is performed through audio-only listening tests, where participants evaluate unrelated, context-free utterances. The ecological validity of ...

When a text-to-speech (TTS) system is required to speak world news, a large fraction of the words to be spoken will be proper names originating in a wide variety of languages. Phonetization of these names based on target language letter-to-sound rules will typically be inadequate. This is detrimental not only during synthesis, when inappropriate phone sequences are produced, but also during training, if the system is trained on data from the same domain. This is because poor phonetization during forced alignment based on hidden Markov models can pollute the whole model set, resulting in degraded alignment even of normal target-language words. This paper presents four techniques designed to address this issue in the context of a Swahili TTS system: automatic transcription of proper names based on a lexicon from a better-resourced language; the addition of a parallel phone set and special part-of-speech tag exclusively dedicated to proper names; a manually-crafted phone mapping which allows substitutions for potentially more accurate phones in proper names during forced alignment; the addition in proper names of a grapheme-derived frame-level feature, supplementing the standard phonetic inputs to the acoustic model. We present results from objective and subjective evaluations of systems built using these four techniques.

Feedback generation is an important component of humanhuman communication. Humans can choose to signal support, understanding, agreement or also sceptiscism by means of feedback tokens. Many studie ...

As synthetic voices become more flexible, and conversational systems gain more potential to adapt to the environmental and social situation, the question needs to be examined, how different modific ...