Administrators usually take some network security metrics as important bases to measure network security. Common Vulnerability Scoring System (CVSS) is one of the generally accepted network measurement method. Aiming at the problem that the existing network security measurement based on CVSS could not accurately measure the probability and the impact of network attack at the same time, an improved base metric algorithm based on dependency relationship graph and CVSS was proposed. Firstly, the dependency relationship of the vulnerability nodes in an attack graph was explored to build the dependency relationship graph. Then, the base metric algorithm of the vulnerability in CVSS was modified according to the dependency relationship. Finally, the vulnerability scores in the whole attack graph were aggregated to obtain the probability and the impact of network attack. The results of simulation with simulated attacker show that the proposed algorithm is superior to the algorithm of aggregating CVSS scores in terms of accuracy and credibility, and can get measurement results closer to the actual simulation results.

A new method for embedding watermark in color image which combined Quaternion Discrete Cosine Transform (QDCT) and Singular Value Decomposition (SVD) was proposed. First of all, binary watermark was preprocessed with the help of the Arnold scrambling application and the color image was made block QDCT and SVD by using quaternion theory. Then, a number of image blocks were selected at random by Logistic mapping to realize the embedding of watermark. The experimental results show that this method has strong anti-JPEG compression as well as better robustness to various kinds of noise and filtering.

In the Grid testing, the integration testing was one of the most important. For cutting down the testing cost, the extended Petri net and Extended Event-Process Chain （EEPC） model were taken as the researching base during the integration testing of components. After fusing adequately the excellences of Petri and EEPC in structure expression, qualitative and quantitative analysis, etc., the PRI of components would be sorted through quantitatively analyzing some parameter, such as the using frequency of components. In the end, the testing emphasis would be put on the components that had the more upper PRI, in order to reduce the testing cost in an across-the-board status.