Title
Separation of stationary and non-stationary sources with a generalized eigenvalue problem.
Abstract
Non-stationary effects are ubiquitous in real world data. In many settings, the observed signals are a mixture of underlying stationary and non-stationary sources that cannot be measured directly. For example, in EEG analysis, electrodes on the scalp record the activity from several sources located inside the brain, which one could only measure invasively. Discerning stationary and non-stationary contributions is an important step towards uncovering the mechanisms of the data generating system. To that end, in Stationary Subspace Analysis (SSA), the observed signal is modeled as a linear superposition of stationary and non-stationary sources, where the aim is to separate the two groups in the mixture. In this paper, we propose the first SSA algorithm that has a closed form solution. The novel method, Analytic SSA (ASSA), is more than 100 times faster than the state-of-the-art, numerically stable, and guaranteed to be optimal when the covariance between stationary and non-stationary sources is time-constant. In numerical simulations on wide range of settings, we show that our method yields superior results, even for signals with time-varying group-wise covariance. In an application to geophysical data analysis, ASSA extracts meaningful components that shed new light on the Pi 2 pulsations of the geomagnetic field.
Year
DOI
Venue
2012
10.1016/j.neunet.2012.04.001
Neural Networks
Keywords
Field
DocType
generalized eigenvalue problem,eeg analysis,ssa algorithm,non-stationary source,data analysis,group-wise covariance,real world data,observed signal,analytic ssa,non-stationary contribution,method yields superior result,stationary subspace analysis,stationarity,blind source separation
Superposition principle,Mathematical optimization,Stationary subspace analysis,Closed-form expression,Eigendecomposition of a matrix,Earth's magnetic field,Blind signal separation,Major stationary source,Mathematics,Covariance
Journal
Volume
Issue
ISSN
33
1
1879-2782
Citations 
PageRank 
References 
10
0.64
25
Authors
6
Name
Order
Citations
PageRank
Satoshi Hara16112.40
Kawahara, Yoshinobu231731.30
Takashi Washio31775190.58
Paul Von Bünau430415.80
Terumasa Tokunaga5100.64
Kiyohumi Yumoto6101.99