Sensitivity to initial conditions on the simulation of extratropical cyclone ‘Gong’ formed over North Atlantic

2021 ◽  
Vol 130 (1) ◽  
Author(s):  
P K Pradhan ◽  
Hari Prasad Dasari ◽  
Srinivas Desamsetti ◽  
S Vijaya Bhaskara Rao ◽  
Rambabu Guvvala
Keyword(s):  
North Atlantic ◽  
Initial Conditions ◽  
Extratropical Cyclone ◽  
Sensitivity To Initial Conditions

A New Image Encryption Scheme Using Dual Chaotic Map Synchronization

2020 ◽  
Vol 18 (1) ◽  
Keyword(s):  
Image Encryption ◽  
Chaotic Systems ◽  
Initial Conditions ◽  
Chaotic Map ◽  
Security Applications ◽  
The Common ◽  
And Diffusion ◽  
Confusion And Diffusion ◽  
Sensitivity To Initial Conditions ◽  
Diffusion Properties

Chaotic systems behavior attracts many researchers in the field of image encryption. The major advantage of using chaos as the basis for developing a crypto-system is due to its sensitivity to initial conditions and parameter tunning as well as the random-like behavior which resembles the main ingredients of a good cipher namely the confusion and diffusion properties. In this article, we present a new scheme based on the synchronization of dual chaotic systems namely Lorenz and Chen chaotic systems and prove that those chaotic maps can be completely synchronized with other under suitable conditions and specific parameters that make a new addition to the chaotic based encryption systems. This addition provides a master-slave configuration that is utilized to construct the proposed dual synchronized chaos-based cipher scheme. The common security analyses are performed to validate the effectiveness of the proposed scheme. Based on all experiments and analyses, we can conclude that this scheme is secure, efficient, robust, reliable, and can be directly applied successfully for many practical security applications in insecure network channels such as the Internet

scholarly journals Atmospheric Conditions Associated with Labrador Sea Deep Convection: New Insights from a Case Study of the 2006/07 and 2007/08 Winters

2016 ◽  
Vol 29 (14) ◽  
pp. 5281-5297 ◽  
Author(s):  
Who M. Kim ◽  
Stephen Yeager ◽  
Ping Chang ◽  
Gokhan Danabasoglu
Keyword(s):  
North America ◽  
North Atlantic ◽  
Large Scale ◽  
Initial Conditions ◽  
Deep Convection ◽  
La Niña ◽  
Labrador Sea ◽  
Atmospheric Conditions ◽  
Circulation Anomaly ◽  
La Nina

Abstract Deep convection in the Labrador Sea (LS) resumed in the winter of 2007/08 under a moderately positive North Atlantic Oscillation (NAO) state. This is in sharp contrast with the previous winter with weak convection, despite a similar positive NAO state. This disparity is explored here by analyzing reanalysis data and forced-ocean simulations. It is found that the difference in deep convection is primarily due to differences in large-scale atmospheric conditions that are not accounted for by the conventional NAO definition. Specifically, the 2007/08 winter was characterized by an atmospheric circulation anomaly centered in the western North Atlantic, rather than the eastern North Atlantic that the conventional NAO emphasizes. This anomalous circulation was also accompanied by anomalously cold conditions over northern North America. The controlling influence of these atmospheric conditions on LS deep convection in the 2008 winter is confirmed by sensitivity experiments where surface forcing and/or initial conditions are modified. An extended analysis for the 1949–2009 period shows that about half of the winters with strong heat losses in the LS are associated with such a west-centered circulation anomaly and cold conditions over northern North America. These are found to be accompanied by La Niña–like conditions in the tropical Pacific, suggesting that the atmospheric response to La Niña may have a strong influence on LS deep convection.

scholarly journals Nonlinear Behavior of a Magnetic Bearing System

1995 ◽  
Vol 117 (3) ◽  
pp. 582-588 ◽  
Author(s):  
L. N. Virgin ◽  
T. F. Walsh ◽  
J. D. Knight
Keyword(s):  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Nonlinear Behavior ◽  
Analytical Techniques ◽  
Magnetic Bearing ◽  
Forced Response ◽  
The Mathematical Model ◽  
Two Degree Of Freedom ◽  
Sensitivity To Initial Conditions ◽  
Bearing System

This paper describes the results of a study into the dynamic behavior of a magnetic bearing system. The research focuses attention on the influence of nonlinearities on the forced response of a two-degree-of-freedom rotating mass suspended by magnetic bearings and subject to rotating unbalance and feedback control. Geometric coupling between the degrees of freedom leads to a pair of nonlinear ordinary differential equations, which are then solved using both numerical simulation and approximate analytical techniques. The system exhibits a variety of interesting and somewhat unexpected phenomena including various amplitude driven bifurcational events, sensitivity to initial conditions, and the complete loss of stability associated with the escape from the potential well in which the system can be thought to be oscillating. An approximate criterion to avoid this last possibility is developed based on concepts of limiting the response of the system. The present paper may be considered as an extension to an earlier study by the same authors, which described the practical context of the work, free vibration, control aspects, and derivation of the mathematical model.

scholarly journals Dynamic Analysis and Cryptographic Application of a Sinusoidal-polynomial Composite Chaotic System

2021 ◽  
Author(s):  
Hegui Zhu ◽  
Jiangxia Ge ◽  
Wentao Qi ◽  
Xiangde Zhang ◽  
Xiaoxiong Lu
Keyword(s):  
Image Encryption ◽  
Chaotic System ◽  
Chaotic Behavior ◽  
Initial Conditions ◽  
Encryption Algorithm ◽  
Topological Transitivity ◽  
Detailed Simulation ◽  
Definition Of ◽  
Image Encryption Algorithm ◽  
Sensitivity To Initial Conditions

Abstract Owning to complex properties of ergodicity, non-periodic ability and sensitivity to initial states, chaotic systems are widely used in cryptography. In this paper, we propose a sinusoidal--polynomial composite chaotic system (SPCCS), and prove that it satisfies Devaney's definition of chaos: the sensitivity to initial conditions, topological transitivity and density of periodic points. The experimental results show that the SPCCS has better unpredictability and more complex chaotic behavior than the classical chaotic maps. Furthermore, we provide a new image encryption algorithm combining pixel segmentation operation, block chaotic matrix confusing operation, and pixel diffusion operation with the SPCCS. Detailed simulation results verify effectiveness of the proposed image encryption algorithm.

The regional model of Subpolar Gyre based on NEMO 4

2021 ◽  
Author(s):  
Polina Verezemskaya ◽  
Bernard Barnier ◽  
Jean-Marc Molines ◽  
Sergey Gulev ◽  
Alexander Gavrikov
Keyword(s):  
North Atlantic ◽  
Initial Conditions ◽  
Regional Model ◽  
Ocean Modeling ◽  
The Arctic ◽  
Reliable Estimate ◽  
Circulation System ◽  
Subpolar Gyre ◽  
Vertical Coordinate ◽  
Denmark Strait

<p>A regional model of Subpolar Gyre in the North Atlantic is implemented. The NNATL12 model development aimed at a realistic representation of Subpolar Northern Atlantic's complex dynamics during the satellite era (starting from 1993 to nowadays) by using a high-resolution regional model that relies on the most up-to-date atmospheric and lateral forcing datasets and modeling techniques. Configuring this model, we focused on the representation of key processes in the Northern Atlantic, such as Irminger Rings, the boundary currents, deep convection, and convective eddies, dense waters cascading through the narrow straits between the Arctic and the Atlantic basins. NNATL12 model is based on NEMO4. The model domain covers the area between 47-70˚N and 84˚W-10˚E with a grid of 1/12˚ in horizontal and 75 vertical levels. In this region, the model is partially eddy-resolving. Three lateral open boundaries and initial conditions are set from the new GLORYS12 reanalysis (Lellouche et al., 2018). The surface forcing is provided by the new RAS NAAD dynamical hindcast based on the WRF model with a spatial resolution of 14 km (Gavrikov et al. 2020). The model adopted the most recent developments in the forced ocean modeling, such as upper boundary forcing schemes (Renault et al., 2020, Brodeau et al., 2016) and local-sigma vertical coordinate in the area of the overflows (Colombo et al., 2020). The model solution is sensitive to new parameterizations and vertical coordinate, which is demonstrated in various tests. The model provides a reliable estimate of the Subpolar North Atlantic circulation system at the surface and medium depth compared to observations. The model represents the ocean stratification at depths above 2000 m showing higher temperatures in the bottom of the Irminger Sea. At daily timescales, it is capable of representing the volume transport comparable to observed values. Irminger Rings TS-structure and dynamics are simulated consistent with the glider data. Comparing to the reanalysis model overestimates the March mixed layer depths and overextends the region of convection north. At the same time, the short-scale and decadal variability of MLD are reproduced by the model. Significant improvements of the deep stratification are obtained with the implementation of the local-sigma vertical coordinate. The model provides vertical profiles of temperature and salinity similar to the observed ones. However the Denmark Strait overflow waters are still too warm, but this is for a large part due to too warm waters at the sill. The high-frequency variability in the Denmark Strait is also in good accordance with the observations.</p>

Boundedness and Other Theories for Complex Systems

2013 ◽  
pp. 108-125
Keyword(s):  
Initial Conditions ◽  
Traditional Approach ◽  
Deterministic Chaos ◽  
Mathematical Object ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Universal Properties ◽  
The One ◽  
Global Invariant ◽  
Sensitivity To Initial Conditions

A comparison between the concept of boundedness on the one hand, and the theory of self-organized criticality (SOC) and the deterministic chaos on the other hand, is made. The focus is put on the methodological importance of the general frame through which an enormous class of empirical observations is viewed. The major difference between the concept of boundedness and the theory of self organized criticality is that under boundedness, the response comprises both specific and universal part, and thus a system has well defined “identity,” while SOC assumes response as a global invariant which has only universal properties. Unlike the deterministic chaos, the boundedness is free to explain the sensitivity to initial conditions independently from the mathematical object that generates them. Alongside, it turns out that the traditional approach to the deterministic chaos has its ample understanding under the concept of boundedness.

scholarly journals Rotational Behavior of Cometary-type Bodies

1992 ◽  
Vol 152 ◽  
pp. 291-296
Author(s):  
Eric Bois ◽  
Pascal Oberti ◽  
Claude Froeschlé
Keyword(s):  
Qualitative Study ◽  
Rotational Motion ◽  
Numerical Experiments ◽  
Initial Conditions ◽  
Close Approach ◽  
Rotational Behavior ◽  
Comet Nucleus ◽  
Gravitational Perturbation ◽  
The Sun ◽  
Sensitivity To Initial Conditions

The present paper deals with a general dynamical qualitative study of the rotational motion for cometary-type bodies submitted to gravitational torques. Numerical experiments of the evolution of comet nucleus attitude have been then performed, including the Sun and Jupiter's disturbing torques in the model. Results show small effects of the solar gravitational perturbation for Halley-type orbits. Only a very close-approach with Jupiter induces notable effects. The latter configuration presents some interesting sensitivity to initial conditions.

scholarly journals Forest Climax Phenomenon: An Invariance of Scale

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 56 ◽  
Author(s):  
Raimundas Petrokas
Keyword(s):  
Natural Regeneration ◽  
Forest Regeneration ◽  
Forest Succession ◽  
Initial Conditions ◽  
Forest Tree ◽  
Tree Regeneration ◽  
Red Queen Hypothesis ◽  
Habitat Dynamics ◽  
Process Pattern ◽  
Sensitivity To Initial Conditions

We can think of forests as multiscale multispecies networks, constantly evolving toward a climax or potential natural community—the successional process-pattern of natural regeneration that exhibits sensitivity to initial conditions. This is why I look into forest succession in light of the Red Queen hypothesis and focus on the key aspects of ecological self-organisation: dynamical criticality, evolvability and intransitivity. The idea of the review is that forest climax should be associated with habitat dynamics driven by a large continuum of ecologically equivalent time scales, so that the same ecological conclusions could be drawn statistically from any scale. A synthesis of the literature is undertaken in order to (1) present the framework for assessing habitat dynamics and (2) present the types of successional trajectories based on tree regeneration mode in forest gaps. In general, there are four types of successional trajectories within the process-pattern of forest regeneration that exhibits sensitivity to initial conditions: advance reproduction specialists, advance reproduction generalists, early reproduction generalists and early reproduction specialists. A successional trajectory is an expression of a fractal connectivity among certain patterns of natural regeneration in the multiscale multispecies networks of landscape habitats. Theoretically, the organically derived measures of pattern diversity, integrity and complexity, determined by the rates of recruitment, growth and mortality of forest tree species, are the means to test the efficacy of specific interventions to avert the disturbance-related decline in forest regeneration. That is of relevance to the emerging field of biocomplexity research.

Fast constrained global minimax optimization of robot parameters

Robotica ◽  
1998 ◽  
Vol 16 (6) ◽  
pp. 595-605 ◽  
Author(s):  
L. Stocco ◽  
S. E. Salcudean ◽  
F. Sassani
Keyword(s):  
Initial Conditions ◽  
Mass Matrix ◽  
Design Guidelines ◽  
Minimax Optimization ◽  
Global Optimization Algorithm ◽  
Discrete Global Optimization ◽  
Optimum Geometry ◽  
Dynamic Perspective ◽  
Low Sensitivity ◽  
Sensitivity To Initial Conditions

A new global isotropy index (GII) is proposed to quantify the configuration independent isotropy of a robot's Jacobian or mass matrix. A new discrete global optimization algorithm is also proposed to optimize either the GII or some local measure without placing any conditions on the objective function. The algorithm is used to establish design guidelines and a globally optimal architecture for a planar haptic interface from both a kinematic and dynamic perspective and to choose the optimum geometry for a 6-DOF Stewart Platform. The algorithm demonstrates consistent effort reductons of up to six orders of magnitude over global searching with low sensitivity to initial conditions.

Sign in / Sign up

Export Citation Format

Share Document