Accelerated plethysmogram analysis for mental stress applied chaos theory and basic experiments

Recently, it is becoming easy to introduce support machines and monitors in a room and out of doors, because robot technology has made remarkable advance and the cost has decreased. Under this situation, implementation of the environmental system that support human with robot is advanced. The welfare environment is considered special care such as support to stand up, sit up, walk, take a medicine, etc. And, it is important to take a health care: sick, pain, mental stress, etc. A relatively easy measurement is a plethysmogram of the fingertip or earlobe for reason of low restriction. In this paper, authors research a possibility of diagnosis of stress by accelerated plethysmogram applied the criterion which combine two evaluation based on chaos theory; trajectory parallel measure method and size of neighborhood space in chaos attractor. And, it calculates time-series data of accelerated plethysmogram measured from forty-tester using proposed evaluations. Finally, a basic experiment is carried out in order to show the practicality of the proposal technique.