Researchers recently gathered at Tsinghua University in Beijing, China, to share their accomplishments at the 13th annual ACM Conference on Ubiquitous Computing.1 This multidis- ciplinary conference featured advances in sensing technologies and activity-recognition algorithms, novel applications, and results from user evaluations. Smartphones continued to provide a versatile research platform, facilitating application delivery, sensor data cap- ture, and computational social science on captured data.