title: An instance-based algorithm with auxiliary similarity information for the estimation of gait kinematics from wearable sensors.
abstract: Wearable human movement measurement systems are increasingly popular as a means of capturing human movement data in real-world situations. Previous work has attempted to estimate segment kinematics during walking from foot acceleration and angular velocity data. In this paper, we propose a novel neural network [GRNN with Auxiliary Similarity Information (GASI)] that estimates joint kinematics by taking account of proximity and gait trajectory slope information through adaptive weighting. Furthermore, multiple kernel bandwidth parameters are used that can adapt to the local data density. To demonstrate the value of the GASI algorithm, hip, knee, and ankle joint motions are estimated from acceleration and angular velocity data for the foot and shank, collected using commercially available wearable sensors. Reference hip, knee, and ankle kinematic data were obtained using externally mounted reflective markers and infrared cameras for subjects while they walked at different speeds. The results provide further evidence that a neural net approach to the estimation of joint kinematics is feasible and shows promise, but other practical issues must be addressed before this approach is mature enough for clinical implementation. Furthermore, they demonstrate the utility of the new GASI algorithm for making estimates from continuous periodic data that include noise and a significant level of variability.
authors.affiliation: Department of Electrical Engineering and Electronics, The University of Liverpool, Liverpool L69 3GJ, UK. j.y.goulermas@liverpool.ac.uk
authors.forename: John Y
authors.initials: JY
authors.lastname: Goulermas
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Findlow
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Nester
authors.forename: Panos
authors.initials: P
authors.lastname: Liatsis
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Zeng
authors.forename: Laurence P J
authors.initials: LP
authors.lastname: Kenney
authors.forename: Phil
authors.initials: P
authors.lastname: Tresadern
authors.forename: Sibylle B
authors.initials: SB
authors.lastname: Thies
authors.forename: David
authors.initials: D
authors.lastname: Howard
mesh_terms: D000465:Algorithms; D001185:Artificial Intelligence; D001696:Biomechanical Phenomena / Q000295:instrumentation / Q000379:methods*; D003198:Computer Simulation; D005684:Gait / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D008962:Models, Theoretical; D018670:Monitoring, Ambulatory / Q000295:instrumentation / Q000379:methods*; D016571:Neural Networks, Computer; D010363:Pattern Recognition, Automated / Q000379:methods*