Kaikai Liu is a Ph.D. candidate in Electrical and Computer Engineering at the University of Florida (UF) under the supervision of Dr.Xiaolin Andy Li. , he alsosubmitted 6 papers and 3 patents with strong determination for innovation. Dr. Xiaolin (Andy) Li is an associate professor and area chair of Computer Engineering Division in Department of Electrical andComputer Engineering at University of Florida.

• 1. Introduction. 2. Overview of Mobile Systems. 3. Acoustic Ranging and Communication. 4. Localization Algorithms. 5. Guoguo: Enabling Fine-Grained Smartphone Localization. 6. Enhancing Location Accuracy and Robustness via Opportunistic Sensing. 7. Pushing Location Awareness to Context-Aware Augmented Reality. 8. Towards Location-Aware Mobile Social Networks with Missions. 9. Wearable Localization via Mobile Crowd Sensing. 10. Improving Location Services via Social Collaboration. 11. Hiding Media Data via Shaders: Enabling Private Sharing in the Clouds. 12. Conclusion and Future Directions.