International Academy Publishing (IAP)
Recommender Systems (RSs) are used by an ever-increasing number of e-commerce sites to recommend items of interest to the users based on their preferences. Collaborative filtering is one of the most regularly used techniques in RSs that help the users to catch the items of interest from a massive numbers of available items. This technique is based on the idea that a set of like-mind users can help each other to find valuable information. The major challenge in recommender systems is that the user ratings or grades are very often uncertain or vague because it is based on user's tastes, opinions, and perceptions.