Considering the problems that the traditional focused crawler is easy to fall into local optimum and has insufficient topic description, a focused crawler method combining Ontology and Improved Tabu Search (On-ITS) was proposed. First, the topic semantic vector was calculated by ontology semantic similarity, and the Web page text feature vector was constructed by Hyper Text Markup Language (HTML) Web page text feature position weighting. Then, the vector space model was used to calculate the topic relevance of Web pages. On this basis, in order to analyze the comprehensive priority of link, the topic relevance of the link anchor text and the PR (PageRank) value of Web page to the link were calculated. In addition, to avoid the crawler falling into local optimum, the focused crawler based on ITS was designed to optimize the crawling queue. Experimental results of the focused crawler on the topics of rainstorm disaster and typhoon disaster show that, under the same environment, the accuracy of the On-ITS method is higher than those of the contrast algorithms by maximum of 58% and minimum of 8%, and other evaluation indicators of the proposed algorithm are also very excellent. On-ITS focused crawler method can effectively improve the accuracy of obtaining domain information and catch more topic-related Web pages.

The explosion of data in big data environment brings great challenges to the system structure and capacity of storage system. Nowadays, the development of storage systems tends to be large capacity, low-cost, and high performance. Meanwhile, storage devices such as conventional rotated magnetic Hard Disk Drive (HDD), Solid State Drive (SSD) and Non-Volatile Random Access Memory (NVRAM) have limitations caused by their intrinsic characteristics, leading to the fact that a single kind of storage device cannot meet the requirements above. Hybrid storage which utilized different storage medium was a good solution to this problem. SSD, as a kind of memory wiht high reliability, low energy consumption, high performance is more and more widely applied to hybrid storage system. By combining magnetic disk with the solid-state drives, the advantages of the high performance of SSD and the low-cost, high-capacity features of HDD were taken. The hybrid storage could provide users with large capacity of storage space, guarantee the system's high performance, at the same time reduced the cost. The current research status of the SSD-HDD hybrid storage system was described, different SSD-HDD hybrid storage systems were summarized and classified. In view of two different HDD-SSD hybrid storage architectures, the key technologies and insufficiencies of which were discussed. Prediction of trend and the research focus in the hybrid storage future were discussed at last.

In view of the high time complexity of pixel segmentation, a super pixel segmentation algorithm was proposed for high resolution image. Super pixels instead of the original pixels were used as the segmentation processing elements and the characteristics of Hadoop and the super pixels were combined. Firstly, a static and dynamic adaptive algorithm for multiple tasks was proposed which could reduce the coupling of the blocks in HDFS (Hadoop Distributed File System) and task arranging. Secondly, based on the constraint in the distance and gradient on the super pixel formed by the boundary of super pixel block, a parallel watershed segmentation algorithm was proposed in each Map node task. Meanwhile, two merging strategies were proposed and compared in the super pixel block merging in the Shuffle process. Finally, the combination of super pixels was optimized to complete the final segmentation in the Reduce node task. The experimental results show that the proposed algorithm is superior to the Simple Linear Iterative Cluster (SLIC) algorithm and Normalized cut (Ncut) algorithm in Boundary Recall ratio (BR) and Under segmentation Error (UE), and the segmentation time of the high-resolution image is remarkably decreased.

Due to the better robustness of entangled W state, it is considered to be better qualified as information carrier for quantum information processing and quantum secure communication. Recently, many kinds of quantum direct communication protocols based on four-particle W state or three-particle asymmetric W state have been proposed. However, these protocols either have low communication efficiency or are difficult to be implemented in physics experiment. By utilizing three-particle W state and the mechanism of quantum identity authentication, a new deterministic secure quantum communication protocol was proposed. This protocol consisted of five parts: authentication code generating, quantum states preparation, quantum states distribution, eavesdropping check and identity authentication, and information communication. The two participants only needed to perform the two-particle Bell measurement, the single-particle 〖WTBX〗Z〖WTBZ〗-basis or 〖WTBX〗X〖WTBZ〗-basis measurement, and the communication efficiency was also improved: One W state can transmit one classical bit of information. The security analysis shows that the present protocol is secure against various eavesdropper Eve's attacks and impersonation attacks, so it has better security.

Remote State Preparation (RSP) is a branch of quantum information processing. In order to prepare the same state to multiple recipients, a broadcast-based RSP protocol was proposed for one sender and two receivers, and then it was extend to N receivers. GHZ states were used as shared quantum resources. By constructing two special measurement bases, the sender realized two times of multi-particle projective measurement; then the receivers used unitary operation to recover the prepared state depending on the measurement results. Analysis shows that multiparty RSP protocol can be used to broadcast information in quantum network.