Collaborative filtering-based recommender systems by effective trust

Collaborative filtering (CF) is one of the most well-known and commonly used techniques to build recommender systems and generate recommendations. However, it suffers from several inherent issues such as data sparsity and cold start. This paper tends to describe the steps based on which the ratings of an active users trusted neighbors are combined to complement and represent the preferences to the active user. First, by discriminating between different users, we calculate the significance of each user to make recommendations. Then, the trusted neighbors of the active user are identified and aggregated. Hence, a new rating profile can be established to represent the preferences of the active user. In the next step, similar users probed based on the new rating profile. Finally, recommendations are generated in the same way as the conventional CF with the difference that if a similar neighbor had not rated the target item, we will predict the value of the target item for this similar neighbor by using the ratings of her directly trusted neighbors and applying MoleTrust algorithm, to combine more similar users to generate a prediction for this target item. Experimental results demonstrate that our method outperforms other counterparts both in terms of accuracy and in terms of coverage. © 2017, Springer International Publishing Switzerland.