Unconstrained detection of freezing of Gait in Parkinson's disease patients using smartphone. - Hanbyul Kim; Hong Ji Lee; Woongwoo Lee; Sungjun Kwon; Sang Kyong Kim; Hyo Seon Jeon; Hyeyoung Park; Chae Won Shin; Won-Jin Yi; Beom Seok Jeon; Kwang Suk Park (EMBC, 2015)