In this paper, we propose a method for composing templates of lung sound classification. First, we obtain a sequence of power spectra by FFT for each given lung sound and compute a small number of component spectra by ICA for each of the overlapping sets of tens of consecutive power spectra. Second, we put component spectra obtained from various lung sounds into a single set and conduct cluster...

Phase structure of nonlinear dynamical system is governed by the vector field and decides the trajectories. Accordingly, the power spectra of trajectories include the structural field effect on the phase space. In this paper, we develop a method for analyzing phase structure using power spectra of trajectories and reconstitute a potential function in the system. key words: power spectra, potent...

With good time-frequency discrimination ability and flexible time-frequency windows, wavelet transform is now widely used to analysis various signals in time and frequency domain simultaneously. Because of the simple relation between wavelet spectra and local (evolutionary) power spectra of a signal, a new method based on wavelet transform to estimate the local power spectra of earthquake groun...