an improved method is proposed to skip the look-ahead period in this paper. The improved method uses the autocorrelation algorithm to calculate the Linear Prediction (LP) coefficients and then the LP coefficients are employed to extrapolate new samples for replacing the look-ahead samples. To evaluate the quality of this method, perceptual evaluation of speech quality (PESQ) and the A/B listening test method are designed for the objective evaluation and subjective evaluation. The reconstructed quality of the modified method is near to the original AMR codec, at the same time, the delay of the improved method is lower 5ms than the original method.

This papers deals with wavelet analysis which is as a tool for the complexity of structural damage combing the multi-scale theory and pattern recognition idea. The main subject is as follows multi-scale damage information analysis and numerical simulation and model experiments which is based on wavelet analysis for structural damage identification study. Applying wavelet transform, differential eqution of structural dynamic system are decomposed and dynamic parameters are described on different scales, the dentification of structure damage location is also spatial domain information which determines in the structural damage.