Recognition of a Quasi-Periodic Sequence Containing an Unknown Number of Nonlinearly Extended Reference Subsequences

2021 ◽  
Vol 61 (7) ◽  
pp. 1153-1161
Author(s):  
A. V. Kel’manov ◽  
L. V. Mikhailova ◽  
P. S. Ruzankin ◽  
S. A. Khamidullin
1983 ◽  
Vol 133 ◽  
pp. 207-216 ◽  
Author(s):  
John W. Miles

The evolution of a weakly nonlinear, weakly dispersive gravity wave in water of depth d over a bottom of gradual slope δ and Chezy friction coefficient Cf is studied. It is found that an initially sinusoidal wave evolves into a periodic sequence of solitary waves with relative amplitude a/d = α1 = 15δ/4Cf if α1 < αb, where αb is the relative amplitude above which breaking occurs. This prediction is supported by observations (Wells 1978) of the evolution of swell over mudflats.


2021 ◽  
Vol 27 (10) ◽  
pp. 531-541
Author(s):  
G. N. Zhukova ◽  
◽  
M. V. Ulyanov ◽  
◽  

The problem of constructing a periodic sequence consisting of at least eight periods is considered, based on a given sequence obtained from an unknown periodic sequence, also containing at least eight periods, by introducing noise of deletion, replacement, and insertion of symbols. To construct a periodic sequence that approximates a given one, distorted by noise, it is first required to estimate the length of the repeating fragment (period). Further, the distorted original sequence is divided into successive sections of equal length; the length takes on integer values from 80 to 120 % of the period estimate. Each obtained section is compared with each of the remaining sections, a section is selected to build a periodic sequence that has the minimum edit distance (Levenshtein distance) to any of the remaining sections, minimization is carried out over all sections of a fixed length, and then along all lengths from 80 to 120 % of period estimates. For correct comparison of fragments of different lengths, we consider the ration between the edit distance and the length of the fragment. The length of a fragment that minimizes the ratio of the edit distance to another fragment of the same length to the fragment length is considered the period of the approximating periodic sequence, and the fragment itself, repeating the required number of times, forms an approximating sequence. The constructed sequence may contain an incomplete repeating fragment at the end. The quality of the approximation is estimated by the ratio of the edit distance from the original distorted sequence to the constructed periodic sequence of the same length and this length.


2017 ◽  
Vol 112 ◽  
pp. 212-220 ◽  
Author(s):  
Héctor J. Carlo ◽  
Víctor David ◽  
Gabriela S. Salvat-Dávila

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