Published on in Vol 7, No 7 (2018): July
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/9379, first published
.

1 Department of Public Health and Nursing , Norwegian University of Science and Technology, Trondheim , NO
2 Department of Computer Science , Norwegian University of Science and Technology, Trondheim , NO