Recommender systems seek to find the interesting items by filtering out the worthless items. Collaborative filtering is one of the most successful recommendation approaches. It typically associates a user with a group of like-minded users based on their preferences over all the items and...

In this article, the authors consider the basic problem of recommender systems that is identifying a set of users to whom a given item is to be recommended. In practice recommender systems are run against huge sets of users, and the problem is then to avoid scanning the whole user set in order...

One of the marvels of our time is the unprecedented development and use of technologies that support social interaction. Social mediating technologies have engendered radically new ways of information and communication, particularly during events; in case of natural disaster like earthquakes...