Multi-class classification of biomechanical data: A functional LDA approach based on multi-class penalized functional PLS
Identificadores
URI: http://hdl.handle.net/10481/72027Metadatos
Afficher la notice complèteMateria
functional data linear discriminant analysis multi-class classification PLS regression P-spline penalty
Date
2019-07Referencia bibliográfica
Aguilera-Morillo MC, Aguilera AM. Multi-class classification of biomechanical data: A functional LDA approach based on multi-class penalized functional PLS. Statistical Modelling. 2020;20(6):592-616. doi:10.1177/1471082X19871157
Patrocinador
MTM2017-88708-P, Spanish Ministry of Economy and Competitiveness (also supported by the FEDER program) and IJCI-2017-34038, Agencia Estatal de Investigación, Ministerio de Ciencia, Innovación y Universidades.Résumé
A functional linear discriminant analysis approach to classify a set of kinematic data (human
movement curves of individuals performing different physical activities) is performed. Kinematic data,
usually collected in linear acceleration or angular rotation format, can be identified with functions
in a continuous domain (time, percentage of gait cycle, etc.). Since kinematic curves are measured in
the same sample of individuals performing different activities, they are a clear example of functional
data with repeated measures. On the other hand, the sample curves are observed with noise. Then,
a roughness penalty might be necessary in order to provide a smooth estimation of the discriminant
functions, which would make them more interpretable. Moreover, because of the infinite dimension
of functional data, a reduction dimension technique should be considered. To solve these problems,
we propose a multi-class approach for penalized functional partial least squares (FPLS) regression.
Then linear discriminant analysis (LDA) will be performed on the estimated FPLS components. This
methodology is motivated by two case studies. The first study considers the linear acceleration recorded
every two seconds in 30 subjects, related to three different activities (walking, climbing stairs and down
stairs). The second study works with the triaxial angular rotation, for each joint, in 51 children when
they completed a cycle walking under three conditions (walking, carrying a backpack and pulling a
trolley). A simulation study is also developed for comparing the performance of the proposed functional
LDA with respect to the corresponding multivariate and non-penalized approaches.