AAPE	Amplitude aware permutation entropy
ANN	Artificial neural network
ApEn	Approximate entropy
CMFDE	Composite multiscale fluctuation-based dispersion entropy
CNN	Convolutional neural network
CVs	Coefficients of variation
CWRU	Case Western Reserve University
CWT	Continuous wavelet transform
DE	Dispersion entropy
DLZC	Dispersion Lempel-Ziv complexity
EEMD	Ensemble empirical mode decomposition
ELM	Extreme learning machine
EMD	Empirical mode decomposition
FDE	Fluctuation-based dispersion entropy
FDLZC	Fluctuation-based DLZC
GA-ELM	Genetic algorithm optimized extreme learning machine
GRCMFE	Generalized refined composite multiscale fuzzy entropy
GSA-SVM	Gravitational search algorithm optimized support vector machine
HCNN	Hierarchical convolutional neural network
HFDE	Hierarchical fluctuation-based dispersion entropy
HRCMFDE	Hierarchical refined composite multiscale fluctuation-based dispersion entropy
IFBE	Improved frequency band entropy
IMFs	Intrinsic mode functions
KELM	Kernel extreme learning machine
k-NN	K-nearest neighbor
LMD	Local mean decomposition
LSVM	Linear support vector machine
LZC	Lempel-Ziv complexity
MAAPE	Multiscale amplitude aware permutation entropy
MFDE	Multiscale fluctuation-based dispersion entropy
MFPT	Machinery Fault Prevention Technology
M-RVM	Multiclass relevance vector machine
MSE	Multiscale entropy
MSST	Multi-synchro-squeezing transform
NCDF	Normal cumulative distribution function
NPLSSMM	Non-parallel least squares support matrix machine
PCA	Principal component analysis
PE	Permutation entropy
PSO	Particle swarm optimization
PSO-ELM	Particle swarm optimization-based extreme learning machine
RCMFDE	Refined composite multiscale fluctuation-based dispersion entropy
RCMFDLZC	Refined composite multiscale FDLZC
RNN	Recurrent neural network
SD	Standard deviation
SE	Sample entropy
SFC-DL	Sparse feature coding based on dictionary learning
SLFN	Single-hidden layer feedforward neural network
sps	sample per second
STMSST	Second-order time-reassigned multi-synchro-squeezing transform
SVM	Support vector machines
VMD	Variational mode decomposition
WGN	White Gaussian noise
WPT	Wavelet packet transform
WT	Wavelet transform
WTFD	Wavelet time-frequency diagram