The effect of the position of the electric field shield on the static neutralization characteristics of an AC corona discharge air ionizer was investigated. The shield was placed at a position D ES between 50 mm and 450 mm below the ionizer, and the neutralizing current density J W and the electric field E W at the work area were measured. The ratio of J W to E W was calculated since a high neutralizing current density and a low electric field are required for ionizers. The ratio was lower when the shield was located near the emitter or near the worktable. The ratio for the ionizer with the shield located at a distance D ES of 250 mm shows maximum value and was 31 times higher than that for the unshielded ionizer.

A multi-sensor-based ambient sensing system is proposed for estimating the user's comfort/discomfort in response to the lighting condition during desk work. The user's comfort/discomfort is estimated according to facial expression, body sway, writing motion and frequency of drinking measured by sensors embedded in the environment. The purpose of the system is to make a robust estimation even under a lighting condition that induces different feelings of comfort depending on the person. To this end, optimal sensor information is selected adaptively depending on the lighting condition among sensor information measured by multiple sensors. It is experimentally confirmed that the user's comfort/discomfort can be estimated even in such mild lighting conditions. The recognition rate of user's comfort on a seven-point scale is 72% when using only ambient sensors (i.e., the subject does not wear sensors).

A multi-sensor-based ambient sensing system is proposed for estimating the user's comfort/discomfort in response to the lighting condition during desk work. The user's comfort/discomfort is estimated according to facial expression, body sway, writing motion and frequency of drinking measured by sensors embedded in the environment. The recognition rate of the user's comfort/discomfort under the lighting condition that induces different feelings of comfort depending on the user's state of the day is evaluated in an experimental environment. As a result, the recognition rate of the user's comfort/discomfort on a two-point scale is 91% when selecting a suitable combination of ambient sensors. Furthermore, it is suggested that not only information of facial expression but also the information of body sway, writing motion and frequency of drinking is useful for the estimation of comfort/discomfort.