International Journal of Intelligent Engineering and Systems

6

Authors: Xiangye Zeng , Jianfei Liu , Jian Wang

Since polarization mode dispersion (PMD) is a major impairment for high bit rate fiber optics systems, it is an important thing for system performance that an proper designed PMD compensate component. In orderto use degree of polarization (DOP) as the feedbacd control signal in PMD dynamic compensation, the relationship beween DOP and differential group delay (DGD) must be ascertain first. Firstly, with a mono-chromatic assumption, the mathematics expression ofDOP is derived in this paper. Then, the relationship beween DOP and DGDm pulse width, and power splitting ratio is analyzde when optic pulse is Gaussian. At last, an experiment is presented, in which 10Gbit/s RZ pseudo random sequence is adopted, and the experimental results prove the validity of theoretical analysis.

8

Authors: Dongfang Chen, Bing Zhou

This paper presents an oblivious watermarking scheme based on contourlet transform and quantization index modulus modulation (QIMM).The scheme has the following features. First, the proposed scheme makes better use of multidirectional characteristic of contourlet transform and embed the watermark into the 4 directional high pass sub bands. Second, the scheme avoids the problem of selection of wavelet filter banks since approximately the same results are obtained with different contourlet filter banks in watermark embedding and extracting stage. Third, unlike the conventional watermarking schemes, watermark error correction is integrated to enhance the quality and normalized cross correlation (NC) value of the extracted watermark. Fourth, through the introduction of the error correction, the proposed scheme tries to view NC as a standard to judge the watermarking algorithm. As a comparison, experiments are conducted to demonstrate that our scheme is more effective than the former one based on lifting scheme wavelet transform.