In order to achieve the efficient storage and access to the huge amounts of data online, under the hierarchical storage architecture of memory cloud, a model of Migration Model based on Data Significance (MMDS) was proposed. Firstly, the importance of data itself was calculated based on factors of the size of the data itself, the importance of time, the total amount of user access, and so on. Secondly, the potential value of the data was evaluated by adopting users' similarity and the importance ranking of the PageRank algorithm in the recommendation system. The importance of the data was determined by the importance of data itself and its potential value together. Then, data migration mechanism was designed based on the importance of data, The experimental results show that, the proposed model can identify the importance of the data and place the data in a hierarchical way and improved the data access hit rate from the storage system compared with the algorithms of Least Recently Used (LRU), Least Frequently Used (LFU), Migration Strategy based on Data Value (MSDV). The proposed model can alleviate the part pressure of storage and has improved the data access performance.

Video recommender is still confronted with many challenges such as lack of meta-data of online videos, and also it's difficult to abstract features on multi-media data directly. Therefore an Video Recommendation algorithm Fusing Comment analysis and Latent factor model (VRFCL) was proposed. Starting with video comments, it firstly analyzed the sentiment orientation of user comments on multiple videos, and resulted with some numeric values representing user's attitude towards corresponding video. Then it constructed a virtual rating matrix based on numeric values calculated before, which made up for data sparsity to some extent. Taking diversity and high dimensionality features of online video into consideration, in order to dig deeper about user's latent interest into online videos, it adapted Latent Factor Model (LFM) to categorize online videos. LFM enables us to add latent category feature to the basis of traditional recommendation system which comprised of dual user-item relationship. A series of experiments on YouTube review data were carried to prove that VRFCL algorithm achieves great effectiveness.