issues to address.txt

// below are added by Yanyong

(1) intuitively, why is each person's head movement unique? Can we explain the uniqueness? Can we prove it (in addition to use DTW)? Biometric vs gesture?
(2) One reviewer said that that DTW is more for guesture-based passwords insead of intrinsic headmovement characteristics. Is that true?
(3) more computation-efficient DTW
(4) non-DTW-based methods can work with partial input data


(5) the study procedure is incomplete
(6) unsupported claims about behavior biometrics
(7) applications/usecases of headbanger (unlock of the device, fallback authentication, accessing high security content)?

(8) detailed training process is missing