Information Quality in Online Social Networks: A Fast Unsupervised Social Spam Detection Method for Trending Topics - Mahdi Washha; Dania Shilleh; Yara Ghawadrah; Reem Jazi; Florence Sèdes (ICEIS 2017 - Proceedings of the 19th International Conference on Enterprise Information Systems, Volume 2, Porto, Portugal, April 26-29, 2017, 2017)