scholarly journals Characterization of river flow fluctuations via horizontal visibility graphs

2016 ◽  
Vol 444 ◽  
pp. 1003-1011 ◽  
Author(s):  
A.C. Braga ◽  
L.G.A. Alves ◽  
L.S. Costa ◽  
A.A. Ribeiro ◽  
M.M.A. de Jesus ◽  
...  
Keyword(s):  
River Flow ◽  
Horizontal Visibility ◽  
Visibility Graphs ◽  
Flow Fluctuations

The visibility parameter for words and permutations

2013 ◽  
Vol 11 (2) ◽  
Author(s):  
Ligia Cristea ◽  
Helmut Prodinger
Keyword(s):  
Finite Alphabet ◽  
Combinatorics On Words ◽  
Horizontal Visibility ◽  
Visibility Graphs ◽  
Finite Set

AbstractWe investigate the visibility parameter, i.e., the number of visible pairs, first for words over a finite alphabet, then for permutations of the finite set {1, 2, …, n}, and finally for words over an infinite alphabet whose letters occur with geometric probabilities. The results obtained for permutations correct the formula for the expectation obtained in a recent paper by Gutin et al. [Gutin G., Mansour T., Severini S., A characterization of horizontal visibility graphs and combinatorics on words, Phys. A, 2011, 390 (12), 2421–2428], and for words over a finite alphabet the formula obtained in the present paper for the expectation is more precise than that obtained in the cited paper. More importantly, we also compute the variance for each case.

Characterization of Rotating Cavitation in a High Speed Inducer of Liquid Rocket Engine

2011 ◽  
Vol 320 ◽  
pp. 196-201
Author(s):  
Fei Tang ◽  
Li Jia Wen
Keyword(s):  
High Speed ◽  
High Performance ◽  
Rocket Engine ◽  
Liquid Rocket Engine ◽  
Blade Surface ◽  
Cavitation Phenomenon ◽  
Flow Fluctuations ◽  
Blade Cascade ◽  
Liquid Rocket

Rotating cavitation is one of the most important problems in the development of modern high performance rocket pump inducers. In this paper, a numerical simulation of rotating cavitation phenomenon in a 2D blade cascade of liquid rocket engine inducer was carried out using a mixture model based on Rayleigh-Plesset equation. The purpose is to investigate the characterization of rotating cavitation in a high speed inducer. The results show that when sub-synchronous rotating cavitation occurs, the speed for the length of the blade surface cavitation is lower than the speed frequency of rotation shaft with the same direction. The external aspect is that the pressure at the upstream of blades changes synchronous. Thus, the generation of sub-synchronous rotating cavitation is closely related to the changes of flow angel which caused by the flow fluctuations. Hence, elimination of the flow rate redistribution among the flow channel can effectively suppress the occurrence of this phenomenon.

scholarly journals Analytic degree distributions of horizontal visibility graphs mapped from unrelated random series and multifractal binomial measures

2017 ◽  
Vol 119 (4) ◽  
pp. 48008 ◽  
Author(s):  
Wen-Jie Xie ◽  
Rui-Qi Han ◽  
Zhi-Qiang Jiang ◽  
Lijian Wei ◽  
Wei-Xing Zhou
Keyword(s):  
Random Series ◽  
Horizontal Visibility ◽  
Visibility Graphs

scholarly journals DETECTING SERIES PERIODICITY WITH HORIZONTAL VISIBILITY GRAPHS

2012 ◽  
Vol 22 (07) ◽  
pp. 1250160 ◽  
Author(s):  
ANGEL NUÑEZ ◽  
LUCAS LACASA ◽  
EUSEBIO VALERO ◽  
JOSE PATRICIO GÓMEZ ◽  
BARTOLO LUQUE
Keyword(s):  
Time Series ◽  
Graph Theory ◽  
Noise Reduction ◽  
Time Domain ◽  
Generic Properties ◽  
Horizontal Visibility ◽  
Visibility Graphs ◽  
Visibility Algorithm ◽  
In Series ◽  
Periodic Signals

The horizontal visibility algorithm was recently introduced as a mapping between time series and networks. The challenge lies in characterizing the structure of time series (and the processes that generated those series) using the powerful tools of graph theory. Recent works have shown that the visibility graphs inherit several degrees of correlations from their associated series, and therefore such graph theoretical characterization is in principle possible. However, both the mathematical grounding of this promising theory and its applications are in its infancy. Following this line, here we address the question of detecting hidden periodicity in series polluted with a certain amount of noise. We first put forward some generic properties of horizontal visibility graphs which allow us to define a (graph theoretical) noise reduction filter. Accordingly, we evaluate its performance for the task of calculating the period of noisy periodic signals, and compare our results with standard time domain (autocorrelation) methods. Finally, potentials, limitations and applications are discussed.

Characterization of SSMVEP-based EEG signals using multiplex limited penetrable horizontal visibility graph

2019 ◽  
Vol 29 (7) ◽  
pp. 073119 ◽  
Author(s):  
Zhong-Ke Gao ◽  
Wei Guo ◽  
Qing Cai ◽  
Chao Ma ◽  
Yuan-Bo Zhang ◽  
...  
Keyword(s):  
Visibility Graph ◽  
Eeg Signals ◽  
Horizontal Visibility ◽  
Horizontal Visibility Graph
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