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For current steganalysis of the image content-adaptive steganography, there are multiple problems to be improved, such as high difficulty and low accuracy, when detecting images with various contents and textures. For this problem, an improved steganalytic method is proposed in this paper based on the pre-classification and feature selection. First, using the features extracted based on the dependency analysis of image adjacent data, the images with various content and texture complexities are pre-classified as multiple clusters by the K-means algorithms. Then, the performance of existing various steganalytic features are analyzed for different clusters of images, and the optimal features for each cluster are selected for final classification. The experimental results show that the detection accuracy could be improved by the proposed method, and the rationality and availability are also verified. At the same time, the analysis and experimental results in this paper also show that the images with rich content and complex texture should be paid more attention both in steganography and in steganalysis.

Web services are essentially distributed applications that can be universally deployed and invoked using standard protocols. As the number of functional similar Web services increases, how to select Web services that can best meet the requirements of the consumers becomes an ongoing research direction in Web service community. However, the Web service selection is usually driven only by functional requirements, which can't guarantee the real-time validity of the Web services selected. This paper proposes a QoS based Web Services Selection Model (WSSM-Q) to provide QoS support for service publishing and selection. In the model, the QoS of Web services is managed, including defining the QoS model, collecting the QoS information, computing and maintaining the QoS data. Upon the QoS management, the Web services that match the requirements of consumers are ranked for selection according to the overall QoS utility. A prototype system is then implemented and evaluated lastly by experiments.