Madalin Frunzete

Computational Measurements of the Transient Time and of the Sampling Distance That Enables Statistical Independence in the Logistic Map

The paper presents an original statistical approach dedicated to the evaluation of two time intervals which are useful in various chaotic applications, namely: the transient time and the minimum statistical independence sampling distance. The overall procedure relies on Smirnov tests based on two-sample statistic, Kolmogorov-Smirnov tests based on one-sample statistic, a Monte Carlo analysis and an original statistical independence test. The experimental study was performed on the logistic map for different values of its parameter, values considered of much interest in the literature. The proposed statistical approach may guide another experimenter to extend the analysis for other logistic map parameters and also for other chaotic maps.

A study on statistical independence in the tent map

The paper evaluates, by means of an original statistical procedure, the minimum sampling distance that enables to extract statistically independent random variables from the tent map. The experimental results indicate the relationship among the tent map parameter and the statistical independence decision. The study may guide the selection of the suitable tent map parameter for different applications where the statistical independence is of interest.

Statistical behaviour of discrete-time rossler system with time varying delay

In this paper a modified discrete-time chaotic system is presented from the statistical point of view. This chaotic system is used in a cryptosystem and, for improving the presented method used in security data transmission, its structure is changed. The technique is implemented for a Rossler hyperchaotic system. The improvement consists in modifying the existing system in order to obtain a higher robustness for the cryptosystem; for this, a time varying delay is added in its structure.

Observability coefficient for 2D dynamical systems

The behaviour of a dynamical system can provide data for applications in various domains. A classification in term of observability will give the answer for the selection of the instrument which will fit the application. In cryptography the cipher is built with instruments with left-inversibility properties and the observability coefficient is a step further to achieve this purpose.

Continuous Time Dynamical System and Statistical Independence

Dynamical systems can give information and can be used in applications in various domains. It is important to know the type of information which will be extracted. In an era when everybody is speaking and is producing information that can be referred as big data, here, the way to extract relevant information by sampling a signal is investigated. Each state variable of a dynamical system is sampled with a specific frequency in order to obtain data sets which are statistical independent. The system can provide numbers for random generators and the sequence obtained can be easily reproduced. These type of generators can be used in cryptography.

An integrated e-learning platform for use in higher education

With the integration of technology in the education process, the traditional methods of teaching must be supported by a more interactive process. Because of the increased portability of devices and the wide spread use of mobile internet connections, the information consumed daily is increasing at an exponential rate. For this reason, students need to be more involved in the education process and the content must be accessible online and presented in a challenging and interactive manner. This paper presents an e-learning platform used in university education which allows courses distribution and online and offline testing for a variety of subjects.

Image enciphering by using Rössler Map

An approach between chaotic behaviour and image indexing is proposed in this paper. A data-base is ciphered, image by image, by using Rössler Map. The image cryptograms are indexed with different methods: colour histogram, auto-correlogram, Color Co-occurrence Matrix (CCM) or Modified Colour Co-occurrence Matrix (MCCM). The experiments will show that the cryptograms stored are quite the same, so the eavesdropper cannot find any information by looking at a specific cryptogram.