Biblio

The rapid development of the Internet and ecommerce has brought a lot of convenience to people's life. Personalized recommendation technology provides users with services that they may be interested according to users' information such as personal characteristics and historical behaviors. The research of personalized recommendation has been a hot point of data mining and social networks. In this paper, we focus on resolving the problem of data sparsity based on users' rating data and social network information, introduce a set of new measures for social trust and propose a novel personalized recommendation algorithm based on matrix factorization combining trust relevancy. Our experiments were performed on the Dianping datasets. The results show that our algorithm outperforms traditional approaches in terms of accuracy and stability.

The ownership transfer of RFID tag means a tagged product changes control over the supply chain. Recently, Doss et al. proposed two secure RFID tag ownership transfer (RFID-OT) protocols based on quadratic residues. However, we find that they are vulnerable to the desynchronization attack. The attack is probabilistic. As the parameters in the protocols are adopted, the successful probability is 93.75%. We also show that the use of the pseudonym of the tag h(TID) and the new secret key KTID are not feasible. In order to solve these problems, we propose the improved schemes. Security analysis shows that the new protocols can resist in the desynchronization attack and other attacks. By optimizing the performance of the new protocols, it is more practical and feasible in the large-scale deployment of RFID tags.