Institute Investigacion en Comunicacion optica

San Luis Potosí, Mexico

Institute Investigacion en Comunicacion optica

San Luis Potosí, Mexico
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Afraimovich V.S.,Institute Investigacion en Comunicacion Optica | Shilnikov L.P.,Research Institute for Applied Mathematics and Cybernetics
International Journal of Bifurcation and Chaos | Year: 2014

We derive sufficient conditions for the existence of an invariant set in an absorbing region homeomorphic to the product of a multidimensional torus and a ball. This set consists of low dimensional tori labeled by symbolic sequences. It may appear as a result of the breakdown of an attracting multidimensional torus. Trajectories on the set manifest chaotic behavior for some angular coordinates and may behave regularly for others, i.e. the dynamics on the set is of the chimera state type. © 2014 World Scientific Publishing Company.


Murguia J.S.,Autonomous University of San Luis Potosi | Mejia Carlos M.,Institute Investigacion en Comunicacion Optica | Rosu H.C.,San Luis Potosí Institute of Scientific Research and Technology
International Journal of Modern Physics C | Year: 2013

In this paper, we study in detail the multifractal features of the main matrices of an encryption system based on a rule-90 cellular automaton. For this purpose, we consider the scaling method known as the wavelet transform multifractal detrended fluctuation analysis (WT-MFDFA). In addition, we analyze the multifractal structure of the matrices of different dimensions, and find that there are minimal differences in all the examined multifractal quantities such as the multifractal support, the most frequent singularity exponent, and the generalized Hurst exponent. © 2013 World Scientific Publishing Company.


Martinez-Ramirez J.D.,Institute Investigacion en Comunicacion Optica | Quispe-Siccha R.,National Autonomous University of Mexico | Garcia-Segundo C.,National Autonomous University of Mexico | Gonzalez F.J.,Institute Investigacion en Comunicacion Optica | Gutierrez-Juarez G.,University of Guanajuato
Journal of Applied Research and Technology | Year: 2012

Based on the pulsed photoacoustic effect, we set up an experimental system to obtain bi-dimensional images of optically-opaque samples embedded within the bulk of turbid medium. The turbid medium was made of agar gel mixed with single-sized nanoparticles; with these materials we induce an optical absorption and an optical scattering like that appearing in human tissues. The PA signals are generated from the absorption processes in the buried target, and then traveling through the bulk of scatter medium. The optical absorption properties and the shape of target, defines the amplitude and shape of the PA signals. This time the laser pulses are set from a pulsed Nd: YAG laser, with pulse width of 10 ns, at rate repetition of 10 Hz and wavelength set at 1064 nm. The signals generated in this way are registered by means of an ultrasonic transducer with resonance cut at 10 MHz. The sample was rotated to obtain as many as 36 projections which are used to feed an image reconstruction forward-projection algorithm based on the Radon Transform. As result we obtain 2D tomographic slices of three different samples.


Rabinovich M.I.,University of California at San Diego | Afraimovich V.S.,Institute Investigacion en Comunicacion Optica | Varona P.,Autonomous University of Madrid
Dynamical Systems | Year: 2010

Here we consider a new mechanism of binding between different information modalities in the brain, i.e. heteroclinic binding. The basic model that we propose is able to explain the origin of the coordination of competitive dynamics of active brain modes representing the temporal processing of different sensory and/or intrinsic information (different modalities) in parallel. The model describes the coordination of spatio-temporal patterns in the form of sequential switchings corresponding to different modalities. We formulate the conditions for the existence of a multimodality heteroclinic sequence (MHS) in the phase space of this model. Such a sequence appears due to inhibitory connections between different sensory networks that implement a winnerless competition interaction. Computer simulations illustrate the robustness of the switching of the coordinated sequences for different modalities and their mutual regularization and modulation. © 2010 Taylor & Francis.


Rabinovich M.I.,University of California at San Diego | Afraimovich V.S.,Institute Investigacion en Comunicacion Optica | Bick C.,Max Planck Institute for Dynamics and Self-Organization | Varona P.,Autonomous University of Madrid
Physics of Life Reviews | Year: 2012

Timing and dynamics of information in the brain is a hot field in modern neuroscience. The analysis of the temporal evolution of brain information is crucially important for the understanding of higher cognitive mechanisms in normal and pathological states. From the perspective of information dynamics, in this review we discuss working memory capacity, language dynamics, goal-dependent behavior programming and other functions of brain activity. In contrast with the classical description of information theory, which is mostly algebraic, brain flow information dynamics deals with problems such as the stability/instability of information flows, their quality, the timing of sequential processing, the top-down cognitive control of perceptual information, and information creation. In this framework, different types of information flow instabilities correspond to different cognitive disorders. On the other hand, the robustness of cognitive activity is related to the control of the information flow stability. We discuss these problems using both experimental and theoretical approaches, and we argue that brain activity is better understood considering information flows in the phase space of the corresponding dynamical model. In particular, we show how theory helps to understand intriguing experimental results in this matter, and how recent knowledge inspires new theoretical formalisms that can be tested with modern experimental techniques. © 2011.


Vargas-Olmos C.,Autonomous University of San Luis Potosi | Murguia J.S.,Autonomous University of San Luis Potosi | Ramirez-Torres M.T.,Institute Investigacion en Comunicacion Optica | Mejia Carlos M.,Institute Investigacion en Comunicacion Optica | And 2 more authors.
International Journal of Modern Physics C | Year: 2015

The technique of detrended fluctuation analysis (DFA) has been widely used to unveil scaling properties of many different signals. In this paper, we determine scaling properties in the encrypted images by means of a two-dimensional DFA approach. To carry out the image encryption, we use an enhanced cryptosystem based on a rule-90 cellular automaton and we compare the results obtained with its unmodified version and the encryption system AES. The numerical results show that the encrypted images present a persistent behavior which is close to that of the 1/f-noise. These results point to the possibility that the DFA scaling exponent can be used to measure the quality of the encrypted image content. © 2015 World Scientific Publishing Company.


Ramirez-Torres M.T.,Institute Investigacion en Comunicacion Optica | Murguia J.S.,Autonomous University of San Luis Potosi | Carlos M.M.,Institute Investigacion en Comunicacion Optica
International Journal of Modern Physics C | Year: 2014

This paper carries out the image encryption with a revised and modified cryptosystem based on a rule-90 cellular automaton. For this purpose, we used an appropriate and convenient matrix approach to implement the main components of the encryption system, two indexed families of permutations and a pseudo-random bit generator. Furthermore, we modify the encryption scheme for improving its security. This makes our encryption proposal resist some common attacks, e.g. chosen plain-text attack, and the encryption and decryption processes are performed in a flexible way. Also, some security aspects of the cryptosystem are evaluated with a series of statistical tests exhibiting good results. It is believed that this proposal fits naturally in the present digital technology and is capable of achieving high levels of performance. © 2014 World Scientific Publishing Company.


Compean-Jasso V.H.,Institute Investigacion en Comunicacion Optica | De Anda F.,Institute Investigacion en Comunicacion Optica | Mishurnyi V.A.,Institute Investigacion en Comunicacion Optica | Gorbatchev A.Yu.,Institute Investigacion en Comunicacion Optica | And 2 more authors.
Thin Solid Films | Year: 2013

Sn doped GaSb has been grown at 260 C by liquid phase epitaxy. The experiments were done so as to determine if Sn could change its impurity type, from acceptor to donor, at such low growth temperature. It was found that Sn behaves as an acceptor irrespective of the growth temperature or the Sn concentration in the nutrient liquid. The samples were studied by photoluminescence and secondary ion mass spectroscopy. From these experiments the segregation coefficient of Sn in the Ga-Sb-Sn system at 260 C has been measured. Also the activation energy of the Sn acceptor level was determined at 20 K. © 2013 Elsevier B.V. All rights reserved.


Hernandez-Arriaga D.,Institute Investigacion en Comunicacion Optica | Gonzalez-Gonzalez F.,Institute Investigacion en Comunicacion Optica | Segura-Cardenas E.,Institute Investigacion en Comunicacion Optica | Reyes-Reyes M.,Institute Investigacion en Comunicacion Optica | Lopez-Sandoval R.,San Luis Potosí Institute of Scientific Research and Technology
Technical Proceedings of the 2013 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2013 | Year: 2013

The importance of graphene as a new material is due to its electrical and mechanical properties, good conductivity, excellent heat dissipation, flexibility and transparency. Therefore it offers a good suitable material to the actual demands on new technologies. Graphene nanoribbons (GNRs) are obtained by cutting a graphene sheet into quasi-one dimensional infinite ribbons. GNRs are materials showing different properties compared with others carbon nanostructures because they can act from semiconductors to semimetals as a function of their width. In this work, we describe an oxidative method, using only potassium permanganate (KMnC4) as the oxidant agent, for the synthesis of GNRs coming from the unzipping of multi-walled carbon nanotubes, which are synthesized using a mixture of xylene with an alcohol as the carbon source and ferrocene as the catalyst.


Hernandez-Vidales K.,Institute Investigacion en Comunicacion optica | Balderas-Navarro R.E.,Institute Investigacion en Comunicacion optica | Ramirez-Flores G.,Institute Investigacion en Comunicacion optica
Latin America Optics and Photonics Conference, LAOP 2014 | Year: 2014

We described on measurement of change in refractive index for bent Au/PET with digital holographic interferometry. The results obtained show that the changes are proportionality to the reciprocal of the radius.© OSA 2014.

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