Evidences of evanescent Bloch waves in Phononic Crystals

We show both experimentally and theoretically the evanescent behaviour of modes in the Band Gap (BG) of finite Phononic Crystal (PC). Based on experimental and numerical data we obtain the imaginary part of the wave vector in good agreement with the complex band structures obtained by the Extended Plane Wave Expansion (EPWE). The calculated and measured acoustic field of a localized mode out of the point defect inside the PC presents also evanescent behaviour. The correct understanding of evanescent modes is fundamental for designing narrow filters and wave guides based on Phononic Crystals with defects.Comment: 8 pages, 3 figure

Wideband performance comparison between the 40 GHz and 60 GHz frequency bands for indoor radio channels

B

The merging/AGN connection II. Ionization of the circumnuclear regions

We report the first results of a study of a sample of 20 galaxy mergers/interacting systems, using the VIMOS and PMAS integral field spectrographs. For each object, we extracted the integrated spectrum of the central regions and analyzed the ionization state using classical diagnostic diagrams (Veilleux & Osterbrock 1987). There is evidence of AGN ionization in 4 of the objects, i.e. 20% of the sample, a considerably higher fraction than found in previous studies ~4%Comment: 4 pages, 2 figures, accepted for publishing in A&A Letter

Photoionization models of the CALIFA HII regions. I. Hybrid models

Photoionization models of HII regions require as input a description of the ionizing SED and of the gas distribution, in terms of ionization parameter U and chemical abundances (e.g. O/H and N/O). A strong degeneracy exists between the hardness of the SED and U, which in turn leads to high uncertainties in the determination of the other parameters, including abundances. One way to resolve the degeneracy is to fix one of the parameters using additional information. For each of the ~ 20000 sources of the CALIFA HII regions catalog, a grid of photoionization models is computed assuming the ionizing SED being described by the underlying stellar population obtained from spectral synthesis modeling. The ionizing SED is then defined as the sum of various stellar bursts of different ages and metallicities. This solves the degeneracy between the shape of the ionizing SED and U. The nebular metallicity (associated to O/H) is defined using the classical strong line method O3N2 (which gives to our models the status of "hybrids"). The remaining free parameters are the abundance ratio N/O and the ionization parameter U, which are determined by looking for the model fitting [NII]/Ha and [OIII]/Hb. The models are also selected to fit [OII]/Hb. This process leads to a set of ~ 3200 models that reproduce simultaneously the three observations. We find that the regions associated to young stellar bursts suffer leaking of the ionizing photons, the proportion of escaping photons having a median of 80\%. The set of photoionization models satisfactorily reproduces the electron temperature derived from the [OIII]4363/5007 line ratio. We determine new relations between the ionization parameter U and the [OII]/[OIII] or [SII]/[SIII] line ratios. New relations between N/O and O/H and between U and O/H are also determined. All the models are publicly available on the 3MdB database.Comment: Accepted for publication in A&

Lightweight ciphers based on chaotic Map -- LFSR architectures

In this paper, we propose and analyze two different stream ciphers based on a Skew Tent Map and a Modified Logistic Map respectively. In order to improve the randomness of these systems, a single method for increasing the period length of the generated sequences has been applied. The results prove that the randomness of these systems can be severally increased by using this method, making these systems suitable for secure communications.Comment: Proceedings of 2016 12th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME

Mapping the sustainable development goals into the EDINSOST sustainability map of bachelor engineering degrees

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This Research to Practice Work in Progress paper presents the work conducted on the use of the Sustainability Map of Bachelor Engineering Degrees (a tool developed by the EDINSOST project) to analyze how Sustainable Development Goals (SDGs) are developed in each Degree. Over recent years, there has been a growth in the importance of working sustainability based on the SDGs. To identify which learning objective of each SDG corresponds to each learning outcome of the EDINSOST Sustainability Map, a correspondence matrix has been defined. The matrix contains the learning outcomes of the EDINSOST Sustainability Map in its rows, and the 17 SDGs in the columns. The cells of the matrix contain the learning objectives of the SDGs that correspond to each learning outcome of the EDINSOST Sustainability Map. This work in progress presents the first results of the process of mapping the SDGs into the EDINSOST Sustainability Map of Engineering Bachelor Degrees. Early results show that some of the 169 learning objectives are not applicable to Engineering Degrees. Likewise, we have seen that learning objectives have been defined more for policy makers than for engineers, and therefore adaptation is not an easy task. However, the work done has helped us to verify that the EDINSOST Sustainability Map can help in the introduction of the SDGs into the curriculum.Peer ReviewedPostprint (author's final draft

A learning tool to develop sustainable projects

This paper presents a tool developed to help engineers to design and develop sustainable projects. The tool has been designed to introduce and evaluate the sustainability of engineering projects in general, but here we show its application to assess the final project of an engineering degree. This tool is a guide for students to introduce and estimate the sustainability of their projects, but it also helps teachers to assess them. The tool is based on the Socratic Methodology and consists of a matrix where each cell contains several questions that students must consider during the project development and which they must answer in their project report. A positive or negative mark is assigned to every cell, and the sum of all marks states the project sustainability. However, the result is not as simplistic as a final number, but a descriptive sustainability analysis where questions are answered and every mark justified. A pilot test with some students has obtained good results, but the first Final Degree Project using this methodology will be read in July 2016.Peer ReviewedPostprint (author's final draft

A new simple technique for improving the random properties of chaos-based cryptosystems

A new technique for improving the security of chaos-based stream ciphers has been proposed and tested experimentally. This technique manages to improve the randomness properties of the generated keystream by preventing the system to fall into short period cycles due to digitation. In order to test this technique, a stream cipher based on a Skew Tent Map algorithm has been implemented on a Virtex 7 FPGA. The randomness of the keystream generated by this system has been compared to the randomness of the keystream generated by the same system with the proposed randomness-enhancement technique. By subjecting both keystreams to the National Institute of Standards and Technology (NIST) tests, we have proved that our method can considerably improve the randomness of the generated keystreams. In order to incorporate our randomness-enhancement technique, only 41 extra slices have been needed, proving that, apart from effective, this method is also efficient in terms of area and hardware resources