The service conditions of underground coal mine equipment are poor, and it is difficult to accurately extract the fault characteristics rolling bearings. In order better improve accuracy identification bearings, a fault-detection method based on multiscale permutation entropy SOA-SVM proposed. First, whale optimization algorithm used select modal analysis number K penalty factor α variational m...

Let n≥ 2 be an integer and let P = {1,2, . . . ,n,n+1}. Let Zp denote the finite field {0,1,2, . . . , p−1}, where p ≥ 2 is a prime. Then every map σ on P determines a real n×n Petrie matrix Aσ which is known to contain information on the dynamical properties such as topological entropy and the Artin-Mazur zeta function of the linearization of σ . In this paper, we show that if σ is a cyclic pe...

by a quasi-permutation matrix we mean a square matrix over the complex field c with non-negative integral trace. thus, every permutation matrix over c is a quasipermutation matrix. for a given finite group g, let p(g) denote the minimal degree of a faithful permutation representation of g (or of a faithful representation of g by permutation matrices), let q(g) denote the minimal degree of a fai...

Motivated by a geometrical Thue-type problem, we introduce a new variant of the classical pattern avoidance in words, where jumping over a letter in the pattern occurrence is allowed. We say that pattern p ∈ E+ occurs with jumps in a word w = a1a2 . . . ak ∈ A+, if there exist a non-erasing morphism f from E∗ to A∗ and a sequence (i1, i2, . . . , il) satisfying ij+1 ∈ {ij + 1, ij + 2} for j = 1...