Teng Yuntian

Seismic data compression based on integer wavelet transform

Due to the particularity of the seismic data, they must be treated by lossless compression algorithm in some cases. In the paper, based on the integer wavelet transform, the lossless compression algorithm is studied. Comparing with the traditional algorithm, it can better improve the compression rate. CDF (2, n) biorthogonal wavelet family can lead to better compression ratio than other CDF family, SWE and CRF, which is owe to its capability in canceling data redundancies and focusing data characteristics. CDF (2, n) family is suitable as the wavelet function of the lossless compression seismic data.

An earthquake data acquisition system for mobile observation

Besides the same performance as the earthquake observation system possess used on the fixed earthquake station, such as wide dynamic range, high resolution, following special features are necessary for the earthquake data acquisition system (EDAS) applied for mobile observing in order to suit for running in the field: a) Reliability. The EDAS must work stably long time without being cared. b) Adaptability to the field environments. Earthquake observing in the field often encounters awful environments, such as dampness, dust, and abnormal climate, so how to make the instrument run well in the field circumstance must be considered. c) Ability of anti-vibration. The instrument for outdoor application must keep free from being destroyed during being transported long distance to the destination. d) Storage capacity. Because seismological data is large, how to store and collect the large amount data conveniently from the field is always a difficult point in the mobile observing system design. e) Automation. Timing and positioning automatically is necessary in the field. f) Power consumption. To reduce the power con-sumption as low as possible is very important to the mobile instrument which are powered with battery. g) Ability of testing itself. Testing itself automatically make it convenient in the fieldwork. h) Portability. The instrument must be portable and simply operated.