Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of Seismocardiographic Signals Using Polynomial Chirplet
  Transform and Smoothed Pseudo Wigner-Ville Distribution   Seismocardiographic (SCG) signals are chest surface vibrations induced by
cardiac activity. These signals may offer a method for diagnosing and
monitoring heart function. Successful classification of SCG signals in health
and disease depends on accurate signal characterization and feature extraction.
One approach of determining signal features is to estimate its time-frequency
characteristics. In this regard, four different time-frequency distribution
(TFD) approaches were used including short-time Fourier transform (STFT),
polynomial chirplet transform (PCT), Wigner-Ville distribution (WVD), and
smoothed pseudo Wigner-Ville distribution (SPWVD). Synthetic SCG signals with
known time-frequency properties were generated and used to evaluate the
accuracy of the different TFDs in extracting SCG spectral characteristics.
Using different TFDs, the instantaneous frequency (IF) of each synthetic signal
was determined and the error (NRMSE) in estimating IF was calculated. STFT had
lower NRMSE than WVD for synthetic signals considered. PCT and SPWVD were,
however, more accurate IF estimators especially for the signal with
time-varying frequencies. PCT and SPWVD also provided better discrimination
between signal frequency components. Therefore, the results of this study
suggest that PCT and SPWVD would be more reliable methods for estimating IF of
SCG signals. Analysis of actual SCG signals showed that these signals had
multiple spectral components with slightly time-varying frequencies. More
studies are needed to investigate SCG spectral properties for healthy subjects
as well as patients with different cardiac conditions.

27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin