For nonlinear feedback shift registers （NFSRs）, their greatest common subfamily may be not unique. Given two NFSRs, the authors only consider the case that their greatest common subfamily exists and is unique. If th...For nonlinear feedback shift registers （NFSRs）, their greatest common subfamily may be not unique. Given two NFSRs, the authors only consider the case that their greatest common subfamily exists and is unique. If the greatest common subfamily is exactly the set of all sequences which can be generated by both of them, the authors can determine it by Grobner basis theory. Otherwise, the authors can determine it under some conditions and partly solve the problem.展开更多
JPEG Steganalysis is an important technique for forensic analysis of images on online social networks. This paper proposes a novel hierarchical learning framework for JPEG steganalysis. It is based on the observation ...JPEG Steganalysis is an important technique for forensic analysis of images on online social networks. This paper proposes a novel hierarchical learning framework for JPEG steganalysis. It is based on the observation that both regions of an image with different textural complexity and regions of different images with similar textural complexity tend to have different embedding probabilities. In the training stage of our framework, images are firstly clustered into a number of categories using Gaussian Mixture Model (GMM). Then, images in each category are decomposed into smaller blocks, and these blocks are also clustered into limited classes. Finally, a classifier is trained for each class of blocks.In the testing stage, an image and its blocks are also classified using trained GMM, and each block is tested on corresponding classifiers to make the final decision by weighed sum of individual results. Extensive experimental results show a better performance of our framework compared with some other previous learning framework.展开更多
基金supported by the Natural Science Foundation of China under Grant Nos.61272042,61100202and 61170235
文摘For nonlinear feedback shift registers （NFSRs）, their greatest common subfamily may be not unique. Given two NFSRs, the authors only consider the case that their greatest common subfamily exists and is unique. If the greatest common subfamily is exactly the set of all sequences which can be generated by both of them, the authors can determine it by Grobner basis theory. Otherwise, the authors can determine it under some conditions and partly solve the problem.
文摘JPEG Steganalysis is an important technique for forensic analysis of images on online social networks. This paper proposes a novel hierarchical learning framework for JPEG steganalysis. It is based on the observation that both regions of an image with different textural complexity and regions of different images with similar textural complexity tend to have different embedding probabilities. In the training stage of our framework, images are firstly clustered into a number of categories using Gaussian Mixture Model (GMM). Then, images in each category are decomposed into smaller blocks, and these blocks are also clustered into limited classes. Finally, a classifier is trained for each class of blocks.In the testing stage, an image and its blocks are also classified using trained GMM, and each block is tested on corresponding classifiers to make the final decision by weighed sum of individual results. Extensive experimental results show a better performance of our framework compared with some other previous learning framework.
