@inproceedings{cornelius:same-body, author = {Cory Cornelius and David Kotz}, title = {Recognizing whether sensors are on the same body}, booktitle = {Proceedings of the International Conference on Pervasive Computing}, year = {2011}, month = {June}, series = {Lecture Notes in Computer Science}, volume = {6696}, pages = {332--349}, publisher = {Springer-Verlag}, copyright = {Springer-Verlag}, doi = {10.1007/978-3-642-21726-5_21}, url = {http://www.cs.dartmouth.edu/~dfk/papers/cornelius-same-body.pdf}, abstract = {As personal health sensors become ubiquitous, we also expect them to become interoperable. That is, instead of closed, end-to-end personal health sensing systems, we envision standardized sensors wirelessly communicating their data to a device many people already carry today, the cellphone. In an open personal health sensing system, users will be able to seamlessly pair off-the-shelf sensors with their cellphone and expect the system to {\it just work}. However, this ubiquity of sensors creates the potential for users to accidentally wear sensors that are not necessarily paired with their own cellphone. A husband, for example, might mistakenly wear a heart-rate sensor that is actually paired with his wife's cellphone. As long as the heart-rate sensor is within communication range, the wife's cellphone will be receiving heart-rate data about her husband, data that is incorrectly entered into her own health record. \par We provide a method to probabilistically detect this situation. Because accelerometers are relatively cheap and require little power, we imagine that the cellphone and each sensor will have a companion accelerometer embedded with the sensor itself. We extract standard features from these companion accelerometers, and use a pair-wise statistic~-- coherence, a measurement of how well two signals are related in the frequency domain~-- to determine how well features correlate for different locations on the body. We then use these feature coherences to train a classifier to recognize whether a pair of sensors~-- or a sensor and a cellphone~-- are on the same body. We evaluate our method over a dataset of several individuals walking around with sensors in various positions on their body and experimentally show that our method is capable of achieving an accuracies over 80\%.} }