How to find negative emotion burst topic in time from massive and noisy microblog text stream is essential for emergency response and handling of emergencies. However, the traditional burst topic detection methods often ignore the differences between negative emotion burst topic and non-negative emotion burst topic. Therefore, a Negative Emotion Burst Topic Detection (NE-BTD) algorithm for microblog text stream was proposed. Firstly, the accelerations of keyword pairs in microblog and the change rate of negative emotion intensity were used as the basis for judging the topics of negative emotion. Secondly, the speeds of burst word pairs were used to determine the window range of negative emotion burst topics. Finally, a Gibbs Sampling Dirichlet Multinomial Mixture model (GSDMM) clustering algorithm was used to obtain the topic structures of the negative emotion burst topics in the window. In the experiments, the proposed NE-BTD algorithm was compared with an existing Emotion-Based Method of Topic Detection (EBM-TD) algorithm. The results show that the NE-BTD algorithm was at least 20% higher in accuracy and recall than the EBM-TD algorithm, and it can detect negative emotion burst topic at least 40 minutes earlier.

The access request for computer network has the characteristics of real-time and dynamic change. In order to detect network intrusion in real time and be adapted to the dynamic change of network access data, a real-time detection framework for network intrusion was proposed based on data stream. First of all, misuse detection model and anomaly detection model were combined. A knowledge base was established by the initial clustering which was made up of normal patterns and abnormal patterns. Secondly, the similarity between network access data and normal pattern and abnormal pattern was measured using the dissimilarity between data point and data cluster, and the legitimacy of network access data was determined. Finally, when network access data stream evolved, the knowledge base was updated by reclustering to reflect the state of network access. Experiments on intrusion detection dataset KDDCup99 show that, when initial clustering samples are 10000, clustering samples in buffer are 10000, adjustment coefficient is 0.9, the proposed framework achieves a recall rate of 91.92% and a false positive rate of 0.58%. It approaches the result of the traditional non-real-time detection model, but the whole process of learning and detection only scans network access data once. With the introduction of knowledge base update mechanism, the proposed framework is more advantageous in the real-time performance and adaptability of intrusion detection.

The fairness of verifiable encrypted signature scheme is completely determined by the arbitrators neutral problem, which reduces the security of signature exchange. In order to deal with this issue, using the properties of bilinear pairings and combining with certificateless public key cryptography and verifiable encrypted signature, a blind verifiable encrypted signature was designed without certificate. The adjudicator in this scheme cannot restore the original signature directly, thereby the security of exchange signature protocols was enhanced. The proposed scheme was also provably secure in the random oracle module under Discrete Logarithm Problem (DLP) and Computational Differ-Hellman Problem (CDHP) assumption.