Voice forgery is detected by digital audio watermarking and pattern recovery techniques. The three methods used by digital watermarking mode for speech signal forgery detection are replacement, insertion and deletion. If some changes are made to the speech signal, the watermark mode will also change, and the mode recovery can be used to measure or detect whether the speech signal has been modified or forged. The proposed method uses the cyclic pattern embedding to overcome synchronizing problems of previous detection techniques. In addition, pattern recovery enhances the robustness to compression. This method has been tested and verified using six recording devices, which was used for collecting verbal data. The speech signals were sampled at the rate of 8 kHz and digitized at 16 bits resolution. Randomly chosen regions were substituted, removed, and compressed in MP3 at the rate of 16 kbps as well as in CELP at the rate of 11.5 kbps. The experiment shows the perfect detection for three kinds of forgeries and it proved the validity of the proposed method.

The wasting of the superheated steam or heating the oil reservoir not sufficiently might be caused by the uncertainty of steam injection period during the steam soak, therefore, and a two-dimensional, unsteady state mineshaft-stratum-oil reservoir mathematical model was established, and the temperature fields of the stratum and the oil reservoir were analyzed. Furthermore, the influences of steam injection period to the heat affected radius during the steam soak were discussed. The results show that the heat affected radius of the oil reservoir increases with steam injection period duration and reaches the maximum when the steaming for 5 d, then nearly no longer changed after that. The heat in the oil reservoir began to transfer to the stratum when the steaming for 3 d, and the temperature fields of the stratum and the oil reservoir are nearly the same for 6 d. The steam injection period should be controlled in 4~5 d during the steam soak.