Kanako Nakayama

Blood pressure estimation from pulse wave velocity measured on the chest

Recently, monitoring of blood pressure fluctuation in the daily life is focused on in the hypertension care area to predict the risk of cardiovascular and cerebrovascular disease events. In this paper, in order to propose an alternative system to the existed ambulatory blood pressure monitoring (ABPM) sphygmomanometer, we have developed a prototype of small wearable device consisting of electrocardiogram (ECG) and photopelthysmograph (PPG) sensors. In addition, it was examined whether blood pressure can be estimated based on pulse wave transit time (PWTT) only by attaching that device on the surface of the chest. We indicated that our system could also sense tendency of time-dependent change of blood pressure by measuring pulse of vessel over the sternum while its propagation distance is short.

Estimation of thermal sensation using human peripheral skin temperature

Control of indoor thermal environments in accordance with peoples preferences, makes an important contribution to comfort. To keep a suitably temperate environment, we tried to estimate a subjects thermal sensation using biologic signals. We focused on peripheral skin temperature to estimate individual thermal sensation. First we carried out an experiment involving an alteration of environmental temperatures to reveal the relationship between peripheral skin temperature and thermal sensation votes. Next we made an algorithm of estimating thermal sensation and assessed the algorithm. When thermal sensation indices estimated by our algorithm were compared with the subjects votes, error of mean squares was 1 or less in most cases. As a result, the possibility of thermal sensation measurement using peripheral skin temperatures is confirmed. Furthermore, we implemented the temperature control system using a household air conditioner and a thermal sensor.