Zhiwen Yu is a Full Professor of Computer Science at Northwestern Polytechnical University, China. He worked as an Alexander Von Humboldt Fellow at Mannheim University, Germany, from November 2009 to October 2010, and as a research fellow at Kyoto University, Japan, from February 2007 to January 2009. His research interests include pervasive computing, context-aware systems, and personalization. He has served as an Associate Editor or Guest Editor for a number of publications, e.g. IEEE Communications Magazine, IEEE THMS, and ACM TIST. Zhu Wang is an Associate Professor of Computer Science at Northwestern Polytechnical University, China. He received his B.Eng., M.Eng. and Ph.D. degrees in Computer Science and Technology in 2006, 2009, and 2013, respectively, from the same university. From 2010 to 2012, he was a research fellow at the Institute TELECOM SudParis, France. His research interests include pervasive computing, social network analysis, and healthinformatics.

• 1. Introduction.- 2. Main Steps of Human Behavior Sensing and Understanding.- 3. Sensor-Based Behavior Recognition.- 4. Device-free Behavior Recognition.- 5. Individual Behavior Recognition.- 6. Group Behavior Recognition.- 7. Community Behavior Understanding.- 8. Open Issues and Emerging Trends.

Zhiwen Yu is a Full Professor of Computer Science at Northwestern Polytechnical University, China. He worked as an Alexander Von Humboldt Fellow at Mannheim University, Germany, from November 2009 to October 2010, and as a research fellow at Kyoto University, Japan, from February 2007 to January 2009. His research interests include pervasive computing, context-aware systems, and personalization. He has served as an Associate Editor or Guest Editor for a number of publications, e.g. IEEE Communications Magazine, IEEE THMS, and ACM TIST. Zhu Wang is an Associate Professor of Computer Science at Northwestern Polytechnical University, China. He received his B.Eng., M.Eng. and Ph.D. degrees in Computer Science and Technology in 2006, 2009, and 2013, respectively, from the same university. From 2010 to 2012, he was a research fellow at the Institute TELECOM SudParis, France. His research interests include pervasive computing, social network analysis, and healthinformatics.

• 1. Introduction.- 2. Main Steps of Human Behavior Sensing and Understanding.- 3. Sensor-Based Behavior Recognition.- 4. Device-free Behavior Recognition.- 5. Individual Behavior Recognition.- 6. Group Behavior Recognition.- 7. Community Behavior Understanding.- 8. Open Issues and Emerging Trends.

Zhiwen Yu is a Full Professor of Computer Science at Northwestern Polytechnical University, China. He worked as an Alexander Von Humboldt Fellow at Mannheim University, Germany, from November 2009 to October 2010, and as a research fellow at Kyoto University, Japan, from February 2007 to January 2009. His research interests include pervasive computing, context-aware systems, and personalization. He has served as an Associate Editor or Guest Editor for a number of publications, e.g. IEEE Communications Magazine, IEEE THMS, and ACM TIST. Zhu Wang is an Associate Professor of Computer Science at Northwestern Polytechnical University, China. He received his B.Eng., M.Eng. and Ph.D. degrees in Computer Science and Technology in 2006, 2009, and 2013, respectively, from the same university. From 2010 to 2012, he was a research fellow at the Institute TELECOM SudParis, France. His research interests include pervasive computing, social network analysis, and healthinformatics.

• 1. Introduction.- 2. Main Steps of Human Behavior Sensing and Understanding.- 3. Sensor-Based Behavior Recognition.- 4. Device-free Behavior Recognition.- 5. Individual Behavior Recognition.- 6. Group Behavior Recognition.- 7. Community Behavior Understanding.- 8. Open Issues and Emerging Trends.