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.
Characterization of total suspended particles (TSP) and inhalable particulate matter (PM10) generated in open pit coal mining areas [Caracterización de partículas suspendidas (PST) y partículas respirables (PM10) producidas en Áreas de explotación carbonífera a cielo abierto]
Angulo L.C.,Popular University of Cesar |
Huertas J.I.,Monterrey Institute of Technology |
Restrepo G.M.,University of Antioquia
Informacion Tecnologica | Year: 2011
This article presents a literature review about the quantification and characterization of total suspended particles (TSP) and inhalable particulate matter (PM10) generated in open pit coal mining areas. Particle matter is a complex pollutant due to its physical characteristics (particle size distribution, morphology and density) and its chemical characteristics (organic and inorganic components, metals, and primary and secondary pollutants). These characteristics are critical to determine the type and the magnitude of their effects on human health. It was found that the different works published in the literature have used lab and field experiments, and also modeling studies. This literature review contributes to improve the understanding and evaluation of technologies that must be used to find solutions to this atmospheric pollution problem.
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.
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.
Analysis and design for the development of software with service-oriented approach: Characteristics and methodological framework [Analisis y diseño para el desarrollo de software con enfoque orientado a servicios: Caracteristicas y un marco metodologico]
Mestre M.R.,Popular University of Cesar |
Ballesteros A.M.L.,Popular University of Cesar
2015 10th Colombian Computing Conference, 10CCC 2015 | Year: 2015
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.