Although recommendation systems have been very successful in both research and practice, they suffer from sparsity and cold-start problems which affect the performance of recommendation badly.

• 推荐系统在理论和实践中都得到了很大发展,但是随着电子商务系统规模的进一步扩大,推荐系统中存在的稀疏问题和冷启动问题严重影响了推荐质量。