Keywords : chaotic

Chaotic Image Steganography using DCT and DWT

Nadia M. Mohammed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2013, Volume 10, Issue 3, Pages 61-73
DOI: 10.33899/csmj.2013.163536

The researchers was interest in the issue of security from long time ago  even  arrived to the current age (the digital age), and because of the importance of this topic and the challenges in it, so this work which included  study and application of new algorithm is proposed to achieve a high level of  security by encrypting the secret message  (image) using the Logistic  Chaotic  function  after the implementation of  Discrete Wavelet Transform (DWT). In the next  phase, it has been implemented the  Discrete Cosine Transform (DCT)  on the cover (image) and then hide the secret message within encrypted data in which  the adoption of the principle of random Blocks which is determined  by  chaotic series.
Deliberately proposed algorithm to provide more of an advantage in it's work, provide ingreliability through data encryption,  message  security, and provided a very high degree of security  through the adoption of the principle of random selected passages  Chaotic, increasing the efficiency of the work of the algorithm and the degree of security.
After the application it must be the use of performance measurements,  so the following was used (NC, BER, PSNR, MSE). The language was  Matlab9.

A Series of Saddle - Node Bifurcation and Chaotic Behavior of a Family of a Semi - Triangular Maps

Salma M. Faris; Ammar A.M. Jameel

AL-Rafidain Journal of Computer Sciences and Mathematics, 2013, Volume 10, Issue 2, Pages 63-77
DOI: 10.33899/csmj.2013.163475

This paper studies the bifurcations in dynamics of a family of semi-triangular maps . We will prove that this family has a series of Saddle-node bifurcations and a period doubling bifurcation. Also, we show that for some value of the parameter the functions  will be chaotic.

Chaotic Watermarking for Authentication

Melad Jader Saeed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2013, Volume 10, Issue 2, Pages 243-257
DOI: 10.33899/csmj.2013.163498

This research concerns with generating and hiding invisible chaotic watermarking, in a manner different from that used in the rest of the known watermarks, has been presented.
The work has two phases in each of which the chaotic function has been used twice. In the first phase it is used to generate the watermark from the same cover picture then embedding it in another level of the cover depending on the chaotic positions in order to increase authenticity and fortification against attacks. As for the second phase, the chaotic function has been used to generate and retrieve the watermark and compare them to ensure authenticity. Through the practical results that were obtained using the measurements of Correlation, PSNR, and MSE the quality of this algorithm has been shown. Some of the image processing procedures have been used to measure the robustness of this algorithm through calculating the correlation coefficient.

Encryption and Hiding Watermarking Using A Chaotic Modified Wavelet Transform

Shaimaa Sh. Mohammad

AL-Rafidain Journal of Computer Sciences and Mathematics, 2011, Volume 8, Issue 2, Pages 87-97
DOI: 10.33899/csmj.2011.163645

In this letter, a new digital watermarking algorithm is proposed to hide binary image watermark inside gray image to increase authentication and robustness, DWT are used in embedding because it has many features in image processing. To increase the effective of this algorithm chaotic logistic map are used to select the embedding position in host chaotically which increase the security and make it hard to be detected, experimental result which be measured by using (Mean Square error, Peak signal to noise ratio , Signal to Noise Ratio, CORLLATION) has value (0.3195, 53.0867, 45.9152, 0.9998) respectively reflect the effective of this algorithm, the watermarked image has no noticeable change, some image processing operation such as(filter ,noise and compression) are used to test the robustness which measured by calculate similarity between extracted watermark after attack and the original one, Programming based on Matlab9.

On Expectation Correlate System and Chaotic Dynamics in Time-Series

Ali Makho Siker

AL-Rafidain Journal of Computer Sciences and Mathematics, 2004, Volume 1, Issue 2, Pages 173-186
DOI: 10.33899/csmj.2004.164117

This paper suggests a new system of time-series called  Expectation Correlate System (ECS) that are good at detecting the behavior of  dynamical  systems (both deterministic and stochastic systems) and the dependence on initial values. A new measure on sensitivity to initial values can be monitored by the newly defined Lyaponov Correlate, so ECS can be a signal to chaotic property. In a stochastic systems, small shifts in some initial value can lead to error in prediction, this property and a new measure to nonlinear systems are study by using the conditional variance of  ECS. All results are computed by using Matlab.

A Study on the Application of Henon with a Case Study of Ecology

Basil Y.Th. Al-Khayat; Inaam H. Abd

AL-Rafidain Journal of Computer Sciences and Mathematics, 2004, Volume 1, Issue 1, Pages 39-57
DOI: 10.33899/csmj.2004.164105

This paper deals with the well known Henon map. Its main properties are studied as well as a non deterministic form. Least squares estimates of parameters of the non deterministic model are driven and a case study from animal ecology is studied, where the population size of the Canadian lynx animal is considered as a time series. The embedding dimension of this time series is estimated and then a mathematical model of the form of suggested non deterministic (stochastic) model is fitted . The chaotic property of this series is studied throughout the fitted model.