With the advent and explosive growth of the Web over the past decade, recommender systems have become at the heart of the business strategies of e-commerce and Internet-based companies such as Google, YouTube, Facebook, Netflix, LinkedIn, Amazon, etc. Hence, the collaborative filtering recommendation algorithms are highly valuable and play a vital role at the success of such businesses in reaching out to new users and promoting their services and products. With the aim of improving the recommendation performance of such an algorithm, this paper proposes a new collaborative filtering recommendation algorithm based on dimensionality reduction and clustering techniques. The ¿-means algorithm and Singular Value Decomposition (SVD) are both used to cluster similar users and reduce the dimensionality. It proposes and evaluates an effective two stage recommender system that can generate accurate and highly efficient recommendations. The experimental results show that this new method significantly improves the performance of the recommendation systems.

The success of applying deep learning to many domains has gained strong interest in developing new revolutionary recommender systems. However, there are little works studying these systems that employ deep learning; additionally, there is no study showing how to combine the users and items embedding with deep learning to enhance the effectiveness of the recommender systems. Therefore, this paper proposes a novel approach called RecDNNing with a combination of embedded users and items combined with deep neural network. The proposed recommendation approach consists of two phases. In the first phase, we create a dens numeric representation for each user and item, called user embedding and item embedding, respectively. Following that, the items and users embedding are averaged and then concatenated before being fed into the deep neural network. In the second phase, we use the model of the deep neural network to take the concatenated users and items embedding as the inputs in order to predict the scores of rating by applying the forward propagation algorithm. The experimental results on MovieLens show that the proposed RecDNNing outperforms state-of-the-art algorithms.