Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Riemann Manifold Model Framework for Longitudinal Changes in Physical
  Activity Patterns   Physical activity (PA) is significantly associated with many health outcomes.
The wide usage of wearable accelerometer-based activity trackers in recent
years has provided a unique opportunity for in-depth research on PA and its
relations with health outcomes and interventions. Past analysis of activity
tracker data relies heavily on aggregating minute-level PA records into
day-level summary statistics, in which important information of PA
temporal/diurnal patterns is lost. In this paper we propose a novel functional
data analysis approach based on Riemann manifolds for modeling PA and its
longitudinal changes. We model smoothed minute-level PA of a day as
one-dimensional Riemann manifolds and longitudinal changes in PA in different
visits as deformations between manifolds. The variability in changes of PA
among a cohort of subjects is characterized via variability in the deformation.
Functional principal component analysis is further adopted to model the
deformations and PC scores are used as a proxy in modeling the relation between
changes in PA and health outcomes and/or interventions. We conduct
comprehensive analyses on data from two clinical trials: Reach for Health (RfH)
and Metabolism, Exercise and Nutrition at UCSD (MENU), focusing on the effect
of interventions on longitudinal changes in PA patterns and how different modes
of changes in PA influence weight loss, respectively. The proposed approach
reveals unique modes of changes including overall enhanced PA, boosted morning
PA, and shifts of active hours specific to each study cohort. The results bring
new insights into the study of longitudinal changes in PA and health and have
the potential to facilitate designing of effective health interventions and
guidelines.

8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th