We analyze locked and unlocked mobile device usage of 1960
		  Android smartphones. Based on approximately 10TB of mobile
		  device data logs collected by the Device Analyzer project,
		  we derive 6.9 million usage sessions using a screen power
		  state machine based approach. From these session we examine
		  the number of interactions per day, the average interaction
		  duration as well as the total daily device usage time.
		  Findings indicate that on average users interact with their
		  devices 117 minutes a day, separated over 57 interactions
		  – while unlocking their device only 43% of the time (e.
		  g. to check for notifications).<br>
<br><pre>@inproceedings{Hintze_14_DiversityinLocked,
  author = {Hintze, Daniel and Findling, Rainhard Dieter and Muaaz, Muhammad and Scholz, Sebastian and Mayrhofer, Ren\'e},
  title = {Diversity in Locked and Unlocked Mobile Device Usage},
  booktitle = {Proc.\ 2014 ACM International Joint Conference on
  		  Pervasive and Ubiquitous Computing: Adjunct Publication
  		  ({UbiComp} 2014)},
  year = {2014},
  pages = {379--384},
  month = sep,
  publisher = {ACM Press},
  note = { {UbiComp/ISWC 2014 Programming Competition winner}},
  booktitle_short = {Adjunct proc. {UbiComp} 2014},
  documenturl = {http://dl.acm.org/citation.cfm?id=2641697},
  doi = {10.1145/2638728.2641697},
  eventurl = {http://ubicomp.org/ubicomp2014/},
  isbn = {978-1-4503-3047-3},
  pubtype = {workshop}
}
</pre>