All subjects are graduate and doctoral students in Tokushima University in Japan. ( 3 ) Feature extraction : we use time domain analysis and frequency domain analysis to extract a combination of EEG features. 所有被试均来自日本德岛(TKS)大学的研究生和博士生。(3)脑电信号的特征提取:本研究采用时域分析和频域分析相结合的方式来提取脑电信号特征。