Symbols		Abbreviations
K	mode number	ApEn	approximate entropy
mk	set of K mode functions	ANN	artificial neural network
ωk	set of central frequencies	ASA	artificial sheep algorithm
∂t	partial derivative of time t	BFA	bacterial foraging algorithm
δt	unit pulse function of time t	BPNN	back-propagation neural network
f(t)	real valued input signal	CWRU	Case Western Reserve University
α	penalty factor for VMD	CQSCA	chaos quantum sine cosine algorithm
β(t)	Lagrange multiplier for VMD	DE	dispersion entropy
w	weight vector	EMD	empirical mode decomposition
b	bias parameter	EEMD	ensemble empirical mode decomposition
ξ	slack term	EWT	empirical wavelet transforms
C	penalty factor for SVM	ELM	extreme learning machine
g	kernel parameter	FE	fuzzy entropy
μi	Lagrange multiplier for SVM	FSDE	fine-sorted dispersion entropy
x	time series	GCMPE	generalized composite multiscale permutation entropy
n	length of time series	HGSA	hybrid gravitational search algorithm
σ	variance of the normal distribution	IMPE	improved multiscale permutation entropy
μ	expectation of the normal distribution	IMDE	improved multiscale dispersion entropy
$y_j^m$	reconstruction matrix of x	IMF	intrinsic mode function
m	embedding dimension	KNN	k-nearest neighbour
τ	time delay	LapSVM	Laplacian support vector machine
c	number of class	LSSVM	least squares support vector machine
$z_j^{m,c}$	class sequence of DE	MSCAPSO	mutation sine cosine algorithm and particle swarm optimization
${\pi }_{v_0{v}_1\dots v_{m-1}}$	dispersion pattern of DE	MHGWOSCA	mutation hybrid grey wolf optimizer and sine cosine algorithm
f	factor of FSDE	mRMR	max-relevance min-redundancy
ρ	precision parameter	MAR	multivariate autoregressive
$z_j^{m,c^{\prime }}$	class sequence of DE	MAE	mean absolute error
${{\pi }_{v_0{v}_1\dots v_{m-1}}}^{\prime }$	dispersion pattern of FSDE	MAPE	root mean square error
Zi	position of individual	PSO	particle swarm optimization
Pi	best position of individual	PE	permutation entropy
vi	velocity of particle	QPSO	quantum behaved particle swarm optimization
si	position of particle	RMSE	mean absolute percentage error
Pibest	individual extreme value	SCA	sine cosine algorithm
Pigbest	global extreme value	SVM	support vector machine
c1, c2	learning factor	SSKMFA	semi-supervised kernel Marginal Fisher analysis
Zijl	position of bottom layer individual	TSMFE	time shift multiscale fuzzy entropy
sil	position of top layer particle	VMD	variational mode decomposition
M	number of top layer particle
N	number of bottom layer individual
G	mutation amplitude
l	current number of iterations