Valledupar, Colombia
Valledupar, Colombia

The Popular University of Cesar , is a public, departmental, coeducational university based primarily in the city of Valledupar, Cesar, Colombia. Wikipedia.


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Vilardy J.M.,Popular University of Cesar | Millan M.S.,Polytechnic University of Catalonia | Perez-Cabre E.,Polytechnic University of Catalonia
Optics and Lasers in Engineering | Year: 2016

A novel nonlinear image encryption scheme based on a fully phase nonzero-order joint transform correlator architecture (JTC) in the Gyrator domain (GD) is proposed. In this encryption scheme, the two non-overlapping data distributions of the input plane of the JTC are fully encoded in phase and this input plane is transformed using the Gyrator transform (GT); the intensity distribution captured in the GD represents a new definition of the joint Gyrator power distribution (JGPD). The JGPD is modified by two nonlinear operations with the purpose of retrieving the encrypted image, with enhancement of the decrypted signal quality and improvement of the overall security. There are three keys used in the encryption scheme, two random phase masks and the rotation angle of the GT, which are all necessary for a proper decryption. Decryption is highly sensitivity to changes of the rotation angle of the GT as well as to little changes in other parameters or keys. The proposed encryption scheme in the GD still preserves the shift-invariance properties originated in the JTC-based encryption in the Fourier domain. The proposed encryption scheme is more resistant to brute force attacks, chosen-plaintext attacks, known-plaintext attacks, and ciphertext-only attacks, as they have been introduced in the cryptanalysis of the JTC-based encryption system. Numerical results are presented and discussed in order to verify and analyze the feasibility and validity of the novel encryption-decryption scheme. © 2016 Elsevier Ltd.


Landinez-Tellez D.A.,National University of Colombia | Deluque Toro C.E.,Popular University of Cesar | Roa-Rojas J.,National University of Colombia
DYNA (Colombia) | Year: 2014

We report the synthesis, the structural characterization, the ferroelectric behavior and the electronic properties of complex perovskite Ba2ZrTiO6. Samples of Ba2ZrTiO6 were synthesized through the standard solid state reaction method. The crystalline structure was studied by means of X-ray diffraction experiments and Rietveld-like analysis. Results reveal that the material crystallizes in a rhomboidal structure, space group R-3 (#148), with cell parameter a=5.8038(7) Å. The ferroelectric response of material was established from curves of polarization as a function of applied electric field. Our results reveal that the double perovskite Ba2ZrTiO6 has a ferroelectric hysteretic behavior at room temperature. The studies of the electronic structure show that Ba2ZrTiO6 behaves as a nonmetallic material with gap energy 2.32 eV. The structural parameters obtained from energy minimization, through the Murnaghan equation state are 99.5% in agreement with the experimental data.


Tapias O.L.,Popular University of Cesar | Salinas S.A.,Pontifical Bolivarian University
2016 Global Medical Engineering Physics Exchanges/Pan American Health Care Exchanges, GMEPE/PAHCE 2016 | Year: 2016

A toolholder robot is proposed for laparoscopy using a Novint Falcon haptic interface, adapted to a laparoscopic forceps through a system of passive joints; this article describes the direct and inverse kinematics for both the interface as well as for the passive joints that form the robot model. The simulation allows to observe that the system maintains a pivotal movement in a Cartesian point of incision, and it is verified that the workspace of the robot will allow conducting training exercises in a simulated abdomen. © 2016 IEEE.


Jimenez C.,University of La Guajira | Torres C.,Popular University of Cesar | Mattos L.,Popular University of Cesar
Journal of Physics: Conference Series | Year: 2011

A new method for image encryption is introduced on the basis of two-dimensional (2-D) generalization of 1-D fractional Hartley transform that has been redefined recently in search of its inverse transform We encrypt the image by two fractional orders and random phase codes. It has an advantage over Hartley transform, for its fractional orders can also be used as addictional keys, and that, of course, strengthens image security. Only when all of these keys are correct, can the image be well decrypted. Computer simulations are also perfomed to confirm the possibilty of proposed method.


Gouveia M.A.,University of Campinas | Avila P.D.,University of Campinas | Avila P.D.,Popular University of Cesar | Marques T.H.R.,University of Campinas | And 2 more authors.
Optics Express | Year: 2015

A hydrostatic pressure sensor based on morphology dependent resonances in a polymeric tube is presented. By internal pressurization, normal tensions will increase the device's size and shrink its wall thickness, inducing a shift in the resonant wavelengths of the resonator. Numerical simulations indicate that there are two modal regimes of sensitivity and a maximum achievable sensitivity, related to the device's geometry, constitutive material and analysed mode order. A sensitivity as high as 0.36 ± 0.01 nm/bar has been experimentally found for a 1.8mm diameter PMMA tube with wall thickness of 80μm. © 2015 Optical Society of America.


Vega F.,Popular University of Cesar | Torres C.,Popular University of Cesar
Journal of Physics: Conference Series | Year: 2015

In this paper we show the design and implementation of a system to capture and analysis of dynamic speckle. The device consists of a USB camera, an isolated system lights for imaging, a laser pointer 633 nm 10 mw as coherent light source, a diffuser and a laptop for processing video. The equipment enables the acquisition and storage of video, also calculated of different descriptors of statistical analysis (vector global accumulation of activity, activity matrix accumulation, cross-correlation vector, autocorrelation coefficient, matrix Fujji etc.). The equipment is designed so that it can be taken directly to the site where the sample for biological study and is currently being used in research projects within the group. © Published under licence by IOP Publishing Ltd.


This article describes a methodological framework for the analysis and design of the development of service-oriented software. This approach to service is an important aspect in the software engineering, as in the last few years has received much attention in the scientific community. It is as well as are various methodologies and techniques that promote the use of services as an element for the development of applications. However, a study of these methodologies is that they are for private use and in other cases are treated in a very general way, without referring to specific proposals. For these reasons, are relevant research methodologies and frameworks, including these new paradigms in the process of developing software. The objective of this work is to analyze the properties of the different methodologies aimed at services in the phases of analysis and design, to propose a framework for inclusive labor where you emphasis to the modeling of services and its architecture. The reason the phases of analysis and design, it is because in these stages is where you apply the principles of service-oriented architecture and it is here where you set the differences of the development of systems. The proposal will be focused on the business, with a targeted approach by models and focused on the architecture of services. © 2015 IEEE.


Vega F.,Popular University of Cesar | Torres C.,Popular University of Cesar
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

The coefficient autocorrelation is a descriptor used in many applications with biospeckle technique. However the analysis of results is through of interpretation of graphs curves. In this paper us proposal a fast algorithm for the linearizing of autocorrelation coefficient; through of the average of slope between autocorrelation coefficients and thus the computing machine can take decisions for many application; for example: fruit classification, maturity detection, storage detection, seeds classification etc. © Copyright 2015 SPIE.


Carrasquilla R.J.,Popular University of Cesar | Neira O.L.,Popular University of Cesar
Journal of Physics: Conference Series | Year: 2011

Time dependent density functional (TD-DFT) calculations were performed on 1,3-benzoxazole and substituted benzoxazoles using the B3LYP functional and the 6-31+G(d) basis sets. The geometry of the S0 and S1 singlet ground and excited states were optimized in gas phase, toluene and methanol using B3LYP/6-31+G(d) y CIS/6-31+G(d) methods, respectively, and the vertical π → π* absorption largest wavelength transitions were determined. Several global molecular descriptors were considered such as the hardness, chemical potential, electronegativity and the dipole moment for each molecule and was determined the influence that has, about the values of these descriptors, the alteration of the main molecular chain of an initial structure (1,3 not substituted Benzoxazole). Generally, the predicted spectra are in agreement with the experimental data.


Vilardy J.M.,Popular University of Cesar | Useche J.,Popular University of Cesar | Torres C.O.,Popular University of Cesar | Mattos L.,Popular University of Cesar
Journal of Physics: Conference Series | Year: 2011

In this paper a technique for the coding of digital images is developed using Fractional Wavelet Transform (FWT) and random phase masks (RPMs). The digital image to encrypt is transformed with the FWT, after the coefficients resulting from the FWT (Approximation, Details: Horizontal, vertical and diagonal) are multiplied each one by different RPMs (statistically independent) and these latest results is applied an Inverse Wavelet Transform (IWT), obtaining the encrypted digital image. The decryption technique is the same encryption technique in reverse sense. This technique provides immediate advantages security compared to conventional techniques, in this technique the mother wavelet family and fractional orders associated with the FWT are additional keys that make access difficult to information to an unauthorized person (besides the RPMs used), thereby the level of encryption security is extraordinarily increased. In this work the mathematical support for the use of the FWT in the computational algorithm for the encryption is also developed.

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