A fast hybrid image cryptosystem based on random generator and modified logistic map

An effective error-correction scheme based on normalized correlation for a non coherent chaos communication system with no redundancy bits is proposed in this paper. A modified logistic map is used in the proposed scheme for generating two sequences, one for every data bit value, in a manner that the initial value of the next chaotic sequence is set by the second value of the present chaotic sequence of the similar symbol. This arrangement, thus, has the creation of successive chaotic sequences with identical chaotic dynamics for error correction purpose. The detection symbol is performed prior to correction, on the basis of the suboptimal receiver which anchors on the computation of the shortest distance existing between the received sequence and the modified logistic map’s chaotic trajectory. The results of the simulation reveal noticeable Eb/No improvement by the proposed scheme over the prior to the error- correcting scheme with the improvement increasing whenever there is increase in the number of sequence N. Prior to the error-correcting scheme when N=8, a gain of 1.3 dB is accomplished in Eb/No at 10-3 bit error probability. On the basis of normalized correlation, the most efficient point in our proposed error correction scheme is the absence of any redundant bits needed with minimum delay procedure, in contrast to earlier method that was based on suboptimal method detection and correction. Such performance would render the scheme good candidate for applications requiring high rates of data transmission.

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An Inverse Pheromone Approach in a Chaotic Mobile Robot’s Path Planning Based on a Modified Logistic Map

Technologies ◽

10.3390/technologies7040084 ◽

2019 ◽

Vol 7 (4) ◽

pp. 84

Author(s):

Eleftherios K. Petavratzis ◽

Christos K. Volos ◽

Lazaros Moysis ◽

Ioannis N. Stouboulos ◽

Hector E. Nistazakis ◽

...

Keyword(s):

Path Planning ◽

Mobile Robots ◽

Efficient Method ◽

Chaotic Motion ◽

Logistic Map ◽

Autonomous Mobile Robots ◽

Motion Pattern ◽

Major Topic ◽

Random Bit Generator ◽

Modified Logistic Map

One major topic in the research of path planning of autonomous mobile robots is the fast and efficient coverage of a given terrain. For this purpose, an efficient method for covering a given workspace is proposed, based on chaotic path planning. The method is based on a chaotic pseudo random bit generator that is generated using a modified logistic map, which is used to generate a chaotic motion pattern. This is then combined with an inverse pheromone approach in order to reduce the number of revisits in each cell. The simulated robot under study has the capability to move in four or eight directions. From extensive simulations performed in Matlab, it is derived that motion in eight directions gives superior results. Especially, with the inclusion of pheromone, the coverage percentage can significantly be increased, leading to better performance.

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ROBUSTNESS OF ADAPTATION IN CONTROLLED SELF-ADJUSTING CHAOTIC SYSTEMS

Fluctuation and Noise Letters ◽

10.1142/s0219477502000919 ◽

2002 ◽

Vol 02 (04) ◽

pp. L285-L292 ◽

Cited By ~ 6

Author(s):

PAUL MELBY ◽

NICHOLAS WEBER ◽

ALFRED HÜBLER

Keyword(s):

Chaotic Dynamics ◽

Chaotic Systems ◽

Logistic Map ◽

Loop Control ◽

Edge Of Chaos ◽

Target Value ◽

Chua Circuit ◽

Modified Logistic Map ◽

Periodic Dynamics ◽

Strong Adaptation

It was recently shown that self-adjusting systems adapt to the edge of chaos. We study the robustness of that adaptation with respect to a controlling force. We first use numerical simulations in a modified logistic map. With these, we find that, if the controlling force has a target value of the parameter that leads to periodic dynamics, the control is successful, even for very small controlling forces. We also find, however, that if the target value for the parameter leads to chaotic dynamics, the parameter resists the control and adaptation to the edge of chaos is still observed. When the controlling force is very strong, adaptation to the edge of chaos is weaker, but still present in the system. We also perform experiments with a self-adjusting Chua circuit and find the same behavior. We quantify these results with a measurement of the robustness of the adaptation as a function of the strength of the controlling force. The control used can be expressed either as a parametric control or as an additive, closed-loop control.

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