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A tree topology based Byzantine fault tolerance system was designed and the calculation of the Byzantine node bound based on depth and width was given.The consistency protocol was designed through divide the tree into groups by communication and work,which guaranteed the safety of system.The access of a node was determined with joint signature mechanism.The Byzantine nodes were placed to the leaves by view change protocol,which guaranteed the liveness of the system.On the foundation of traditional protocol,the new protocol support multiple tasks operating at the same time,and communication between nodes is largely decreased,as well as the space complexity,hence the feasibility being promoted,and the gap between Byzantine fault tolerance system and the non-Byzantine systems being narrowed.

A tree topology based Byzantine fault tolerance system was designed and the calculation of the Byzantine node bound based on depth and width was given.The consistency protocol was designed through divide the tree into groups by communication and work,which guaranteed the safety of system.The access of a node was determined with joint signature mechanism.The Byzantine nodes were placed to the leaves by view change protocol,which guaranteed the liveness of the system.On the foundation of traditional protocol,the new protocol support multiple tasks operating at the same time,and communication between nodes is largely decreased,as well as the space complexity,hence the feasibility being promoted,and the gap between Byzantine fault tolerance system and the non-Byzantine systems being narrowed.

Attribute-based encryption (ABE) provides a fine-grained access control mechanism and it can realize one-to-many secure communication.Proxy re-encryption can transform an encrypted data to another kind encrypted between different domains.Aiming at the demand of secure communication of across-domain naval fleet,a scheme that based on CP-ABE was proposed.At last,a security analysis of this scheme and an example of the scheme were proposed.This scheme combining the technology of ABE and proxy re-encryption realizes a secure communication of across-domain naval fleet and one-to-many secure communication among the naval fleet.At the meantime,it meets the needs of meet and access of vessel.

Attribute-based encryption (ABE) provides a fine-grained access control mechanism and it can realize one-to-many secure communication.Proxy re-encryption can transform an encrypted data to another kind encrypted between different domains.Aiming at the demand of secure communication of across-domain naval fleet,a scheme that based on CP-ABE was proposed.At last,a security analysis of this scheme and an example of the scheme were proposed.This scheme combining the technology of ABE and proxy re-encryption realizes a secure communication of across-domain naval fleet and one-to-many secure communication among the naval fleet.At the meantime,it meets the needs of meet and access of vessel.

Aiming at the phenomenon that there are abrupt reports,similar topics and abundant levels of subtopics in the news,a novel method based on relationship analysis using dependent sentence pattern was proposed for sub-topic detection and tracking (sTDT),which constructed feature dimensions to generate the global vectors according to the increment of TF-IDF,and then created the partial adjoin map based on the connection weights within the time window and decreased the dimensions through dependent sentence pattern.Finally,a novel method for sTDT computing was built with adjoins dictionary weights and time threshold attenuation.Experiments show that the proposed method transferrs the text from linear to plane structure,and extracts the subtopics effectively,of which the minimum DET cost is reduced by at least 2.2 percent than that of classical methods.

Aiming at the phenomenon that there are abrupt reports,similar topics and abundant levels of subtopics in the news,a novel method based on relationship analysis using dependent sentence pattern was proposed for sub-topic detection and tracking (sTDT),which constructed feature dimensions to generate the global vectors according to the increment of TF-IDF,and then created the partial adjoin map based on the connection weights within the time window and decreased the dimensions through dependent sentence pattern.Finally,a novel method for sTDT computing was built with adjoins dictionary weights and time threshold attenuation.Experiments show that the proposed method transferrs the text from linear to plane structure,and extracts the subtopics effectively,of which the minimum DET cost is reduced by at least 2.2 percent than that of classical methods.