Abstract
This study tries to increase the effects of odors by controlling the odor emissions. We developed an olfactory feedback system to maintain user's concentration effectively based on biological information. The system presumes the level of user's concentration based on an electrocardiogram analysis. The analysis is carried out using variance of R-R intervals and frequency spectra. According to the presumed concentration level, the system presents an odor with an awakening effect to maintain user's concentration. We performed experiments in which subjects did simple tasks with this system, changing the method of controlling odor emissions. We compared the results of each method and evaluated the effectiveness of our olfactory feedback system and the methods of controlling odor emissions. The comparison of the results showed that presenting an odor when a user loses his/her concentration is effective to decrease errors of addition tasks.