Started with the regional distribution characteristics, a composite classification model learned on multiple isolated subdomains was proposed to further study the class imbalance problem. In the subdomains division stage, each class was described as ultra-small spheres by improved Support Vector Data Description (SVDD) algorithm, then class domain was divided into intensive and sparse domains. Some instances were founded out from the boundaries of classes and composed of class overlapping domains. In the subdomains cleanup stage, according to sample availability parameters related to domain tightness, noise data was cleaned up by improved K-Nearest Neighbor ( KNN). After combining classifiers sequentially which were learned on isolated subdomains, the Composite Classification model (CCRD) was generated. In the comparison with similar algorithms including SVM (Support Vector Machine), KNN, C4.5 and MetaCost, CCRD can obviously improve the accuracy of positive instances without increasing mistake of negative instances; in the comparison with SMOTE (Synthetic Minority Over-sampling TEchnique) sampling, CCRD can improve the misjudgement of negative instances without affecting the classification of the positive instances; in the experiments on five datasets, the classification performance of CCRD is also improved, especially in Haberman_sur. Experimental results indicate that the composite classification model learned on multiple isolated subdomains has excellent classification capability, and it is an effective method for inbalanced dataset.

In order to deal with the poor security and low efficiency in remote attestation, a module-level safe and efficient property attestation protocol was proposed. In the protocol, the signcryption was used to build the module property signature, which could reduce the time of building property certificate. And the signcryption scheme based on the bilinear pairings over elliptic curves also enhanced the security of property certificate. Finally, a model instance was presented to verify the feasibility of the protocol. The experiments show that the program can quickly generate the module property signature and improves the efficiency of the remote attestation.