A recommendation-support model and a neighborhood-based linear least squares fitting(LLSF)algorithm for the calculation of recommendation-support rating are proposed to solve the low accuracy problem of collaborative filtering based recommender systems on sparse data sets. The model focuses on the probability of users' more interests on the recommended items
and uses the estimation with high recommendation-support rating to replace the traditional expecta-tion estimation so that users'preferred items are found and the accuracy of recommendation is improved. A theoretical analysis shows that the anti-interference ability of the LLSF algorithm is better than those of other algorithms und
er the condition of sparse data sets. The model is also expansible by integrating other models. Experimental results show that the LLSF algorithm improves the recommendation accuracy remarkably. The F
1
score is 3 times of that of the traditional kNN algorithm on the MovieLens data set. The more sparse the data set is
the more the improvement on accuracy obtains. When the sparsity grows from 91% to 99% on the Book-crossing data set
the improvement on F
1
scores increases from 22% to 125%. Moreover
the algorithm can guarantee the ability of long tail mining without loss of recommendation coverage.
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references
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