© 2013 Eerola, Friberg and Bresin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). This Document is Protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission.
Except where otherwise noted, this item's license is described as © 2013 Eerola, Friberg and Bresin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). This Document is Protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission.