scholarly journals Scaling properties of superoscillations and the extension to periodic signals

2016 ◽  
Vol 49 (33) ◽  
pp. 335202 ◽  
Author(s):  
Eugene Tang ◽  
Lovneesh Garg ◽  
Achim Kempf
Keyword(s):  
Scaling Properties ◽  
Periodic Signals

Integrated Fractional white Noise as an Alternative to Multifractional Brownian Motion

2007 ◽  
Vol 44 (02) ◽  
pp. 393-408 ◽  
Author(s):  
Allan Sly
Keyword(s):  
Stochastic Process ◽  
Brownian Motion ◽  
White Noise ◽  
Gaussian Process ◽  
Discrete Data ◽  
Hölder Exponent ◽  
Scaling Properties ◽  
Multifractional Brownian Motion ◽  
Local Properties

Multifractional Brownian motion is a Gaussian process which has changing scaling properties generated by varying the local Hölder exponent. We show that multifractional Brownian motion is very sensitive to changes in the selected Hölder exponent and has extreme changes in magnitude. We suggest an alternative stochastic process, called integrated fractional white noise, which retains the important local properties but avoids the undesirable oscillations in magnitude. We also show how the Hölder exponent can be estimated locally from discrete data in this model.

Investigation of discontinuous periodic signals using the measuring labview complex

2020 ◽  
pp. 72-79
Author(s):  
E.B. Solovyeva ◽  
◽  
Yu.M. Inshakov ◽  
Keyword(s):  
Fourier Series ◽  
Laboratory Experiment ◽  
Gibbs Phenomenon ◽  
Electrical Signals ◽  
Measuring Complex ◽  
Universal Measuring ◽  
Depth Study ◽  
Periodic Signals ◽  
Truncated Fourier Series

General approaches to the analysis of the Gibbs phenomenon for discontinuous periodic signals approximated by the truncated Fourier series are considered. Methods for smoothing the truncated Fourier series and improving its convergence are discussed. The software means for modeling is a universal measuring complex LabVIEW, which possesses a convenient environment for analyzing electrical signals, on the basis of this complex a laboratory experiment is carried out. The advantages of the measuring LabVIEW complex and its capabilities for in-depth study of discontinuous periodic signals are noted.

scholarly journals Galileo L10 Satellites: Orbit, Clock and Signal-in-Space Performance Analysis

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1695
Author(s):  
Constantin-Octavian Andrei ◽  
Sonja Lahtinen ◽  
Markku Poutanen ◽  
Hannu Koivula ◽  
Jan Johansson
Keyword(s):  
Performance Indicators ◽  
Satellite System ◽  
Short Term ◽  
Orbital Inclination ◽  
Navigation Data ◽  
Periodic Signals ◽  
Global Navigation Satellite ◽  
Minor Correction ◽  
Very High

The tenth launch (L10) of the European Global Navigation Satellite System Galileo filled in all orbital slots in the constellation. The launch carried four Galileo satellites and took place in July 2018. The satellites were declared operational in February 2019. In this study, we report on the performance of the Galileo L10 satellites in terms of orbital inclination and repeat period parameters, broadcast satellite clocks and signal in space (SiS) performance indicators. We used all available broadcast navigation data from the IGS consolidated navigation files. These satellites have not been reported in the previous studies. First, the orbital inclination (56.7±0.15°) and repeat period (50680.7±0.22 s) for all four satellites are within the nominal values. The data analysis reveals also 13.5-, 27-, 177- and 354-days periodic signals. Second, the broadcast satellite clocks show different correction magnitude due to different trends in the bias component. One clock switch and several other minor correction jumps have occurred since the satellites were declared operational. Short-term discontinuities are within ±1 ps/s, whereas clock accuracy values are constantly below 0.20 m (root-mean-square—rms). Finally, the SiS performance has been very high in terms of availability and accuracy. Monthly SiS availability has been constantly above the target value of 87% and much higher in 2020 as compared to 2019. Monthly SiS accuracy has been below 0.20 m (95th percentile) and below 0.40 m (99th percentile). The performance figures depend on the content and quality of the consolidated navigation files as well as the precise reference products. Nevertheless, these levels of accuracy are well below the 7 m threshold (95th percentile) specified in the Galileo service definition document.

scholarly journals From Center-Vortex Ensembles to the Confining Flux Tube

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 253
Author(s):  
David R. Junior ◽  
Luis E. Oxman ◽  
Gustavo M. Simões
Keyword(s):  
Degrees Of Freedom ◽  
String Tension ◽  
Effective Field ◽  
Scaling Properties ◽  
Flux Tubes ◽  
Topological Solitons ◽  
Yang Mills ◽  
Center Vortex ◽  
Asymptotic Scaling ◽  
The Continuum

In this review, we discuss the present status of the description of confining flux tubes in SU(N) pure Yang–Mills theory in terms of ensembles of percolating center vortices. This is based on three main pillars: modeling in the continuum the ensemble components detected in the lattice, the derivation of effective field representations, and contrasting the associated properties with Monte Carlo lattice results. The integration of the present knowledge about these points is essential to get closer to a unified physical picture for confinement. Here, we shall emphasize the last advances, which point to the importance of including the non-oriented center-vortex component and non-Abelian degrees of freedom when modeling the center-vortex ensemble measure. These inputs are responsible for the emergence of topological solitons and the possibility of accommodating the asymptotic scaling properties of the confining string tension.

scholarly journals Critical Dynamics of Defects and Mechanisms of Damage-Failure Transitions in Fatigue

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2554
Author(s):  
Oleg Naimark ◽  
Vladimir Oborin ◽  
Mikhail Bannikov ◽  
Dmitry Ledon
Keyword(s):  
Fatigue Damage ◽  
Kinetic Equations ◽  
Experimental Methodology ◽  
Preliminary Deformation ◽  
Scaling Properties ◽  
In Situ Data ◽  
Number Of Cycles ◽  
Fish Eye ◽  
Very High

An experimental methodology was developed for estimating a very high cycle fatigue (VHCF) life of the aluminum alloy AMG-6 subjected to preliminary deformation. The analysis of fatigue damage staging is based on the measurement of elastic modulus decrement according to “in situ” data of nonlinear dynamics of free-end specimen vibrations at the VHCF test. The correlation of fatigue damage staging and fracture surface morphology was studied to establish the scaling properties and kinetic equations for damage localization, “fish-eye” nucleation, and transition to the Paris crack kinetics. These equations, based on empirical parameters related to the structure of the material, allows us to estimate the number of cycles for the nucleation and advance of fatigue crack.

Scaling properties of induction times in heterogeneous nucleation

1991 ◽  
Vol 95 (12) ◽  
pp. 9148-9150 ◽  
Author(s):  
Vitaly A. Shneidman ◽  
Michael C. Weinberg
Keyword(s):  
Heterogeneous Nucleation ◽  
Scaling Properties ◽  
Induction Times

scholarly journals The Effect of Polytetrafluoroethylene (PTFE) Particles on Microstructural and Tribological Properties of Electroless Ni-P+PTFE Duplex Coatings Developed for Geothermal Applications

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 670
Author(s):  
Gifty Oppong Boakye ◽  
Arna María Ormsdóttir ◽  
Baldur Geir Gunnarsson ◽  
Sandeep Irukuvarghula ◽  
Raja Khan ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Tribological Properties ◽  
Complex Geometry ◽  
Corrosion And Wear ◽  
Functional Layer ◽  
Scaling Properties ◽  
Wear Rates ◽  
Mechanical And Tribological Properties ◽  
Duplex Coating ◽  
Wear Protection

The selection of electroless nickel-phosphorus plating (ENP) has been inclined towards their properties and advantages with complex geometry applications. These properties include coating uniformity, low surface roughness, low wettability, high hardness, lubricity, and corrosion- and wear-resistance. Materials used in geothermal environments are exposed to harsh conditions such as high loads, temperature, and corrosive fluids, causing corrosion, scaling, erosion and wear of components. To improve the corrosion- and wear-resistance and anti-scaling properties of materials for geothermal environment, a ENP duplex coating with PTFE nanoparticles was developed and deposited on mild steel within the H2020 EU Geo-Coat project. ENP thin adhesive layer and ENP+PTFE top functional layer form the duplex structure of the coating. The objective of this study was to test the mechanical and tribological properties of the developed ENP-PTFE coatings with varying PTFE content. The microstructural, mechanical and tribological properties of the as-deposited coating with increasing PTFE content in the top functional layer in the order: ENP1, ENP2 and ENP3 were evaluated. The results showed maximum wear protection of the substrates at the lowest load; however, increasing load and sliding cycles increased the wear rates, and 79% increased lubrication was recorded for the ENP2 duplex coating. The wear performance of ENP3 greatly improved with a wear resistance of 8.3 × 104 m/mm3 compared to 6.9 × 104 m/mm3 for ENP2 and 2.1 × 104 m/mm3 for ENP1. The results are applicable in developing low friction, hydrophobic or wear-resistive surfaces for geothermal application.

scholarly journals Chaos for communication

2021 ◽  
Author(s):  
Murilo S. Baptista
Keyword(s):  
Information Content ◽  
Lyapunov Exponents ◽  
Communication System ◽  
Linear Superposition ◽  
Chaotic Signals ◽  
Physical Medium ◽  
Periodic Signals ◽  
Low Probability ◽  
Chaotic Interference ◽  
Source Signals

AbstractThis work shows that chaotic signals with different power spectrum and different positive Lyapunov exponents are robust to linear superposition, meaning that the superposition preserves the Lyapunov exponents and the information content of the source signals, even after being transmitted over non-ideal physical medium. This work tackles with great detail how chaotic signals and their information content are affected when travelling through medium that presents the non-ideal properties of multi-path propagation, noise and chaotic interference (linear superposition), and how this impacts on the proposed communication system. Physical media with other non-ideal properties (dispersion and interference with periodic signals) are also discussed. These wonderful properties that chaotic signals have allow me to propose a novel communication system based on chaos, where information composed from and to multiple users each operating with different base frequencies and that is carried by chaotic wavesignals, can be fully preserved after transmission in the open air wireless physical medium, and it can be trivially decoded with low probability of errors.

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