Dr. Youssef has joined Google on June, 2006 and since then he has been working on location based services. Dr. Youssef received a PhD in Computer Science from University of Maryland, College Park in 2006. His thesis work was on location determination in wireless networks. He has three granted patents and eight pending ones. His research interests include location determination technologies, pervasive computing, sensor networks and protocol modelling. Dr. Youssef is one of the founder of the LBS team at Google and one of the principal engineers behind cellid-based location.