Hugo Enrique Hernandez Figueroa

A novel numerical approach for electromagnetic scattering: the cell method

A new interpolation scheme is proposed in the cell method, a finite volume like method, in order to solve EM scattering problems in the frequency domain. The numerical results, showing an excellent agreement both with the results of method of moments (MoM), finite element method (FEM) and with the theoretical results, confirm the validity and the accuracy of the present approach. Despite the present interpolation scheme leads to non-symmetric constitutive matrices, in the time domain, explicit algorithms can be obtained where such non-symmetric matrices seem to be transformed, for tetrahedrical cells, in symmetric semi-definite positive matrices without any approximation.

Free Visual FDTD 2D Simulator to Support the Telecommunication Teaching-Learning Process

This work presents the integration of different computational techniques to specify and design a new computational electromagnetic simulator, called Free Visual FDTD 2D (FV-FDTD-2D), to support the Telecommunications teaching-learning process. Some Software Engineering, human-computer interface (HCI) and an advanced numerical method, based on Finite Difference Time Domain (FDTD), were successfully integrated. It provides an efficient processing and usable software, which detailed documents for developers and comprehensive graphical output results. The FV-FDTD-2D has been adopted in some technical lectures related to telecommunications, presenting successful evaluations by the attempted public.

Broadband generation of cascaded four-wave mixing products

A new method to efficiently generate broadband cascaded four-wave mixing products is presented. It consists of launching two strong pump waves near the zero-dispersion wavelength of an optical fiber. The obtained bandwidth of Four-Wave Mixing products is width- and wavelength-tunable by adjusting the laser wavelengths and their polarization states. This method has been applied to standard, dispersion-shifted and highly nonlinear fibers (HNLF). The maximum measured bandwidth of 300 nm has been obtained nonlinear fibers by using HNLF.

Predicting complete band-gaps of 2D photonic crystals by using artificial neural networks

In this paper, artificial neural networks are modeled to predict complete band-gaps of bi-dimensional photonic crystals. The available data-set has been generated by an integrated artificial immune network and MPB (MIT Photonic Bands) optimization procedure. Two case studies were carried out, considering square lattice photonic crystals composed of two and three silicon round rods embedded in air. Results from tests showed the modeled artificial neural networks are capable of estimating complete band-gaps across the proposed range of rods.

Complete band-gap prediction of 2D photonic crystals by using multilayer perceptron

In this paper, a Multilayer Perceptron artificial neural network is modeled to estimate complete photonic band-gaps (C-PBGs) of bi-dimensional photonic crystals. Unit cells of square lattice photonic crystals, composed of two silicon round rods and embedded in air, have been designed by an artificial immune network algorithm, and their geometries have been stored in a database along with their C-PGBs. Tests using unknown unit cells assess and demonstrate the C-PBG predicting capability of the modeled Multilayer Perceptron.

Human-Computer Interface Techniques to Design and Evaluate an Electromagnetic Simulator

This work presents the interrelation of software engineering and computational semiotics applied to establish a new procedure to design and specify electromagnetic simulator, contributing to define a possible solution for a complex usability problem for engineers and scientists who wants to use this type of computational approach. It is justified by the large number of Physical properties necessary to perform any numerical simulation, specially, for telecommunications. In this work the main integrated techniques are Service Oriented Architecture (SOA), Nielsen principles with severity levels, signs representations from computational semiotics and a cognitive route technique, and they were integrated to establish a procedure to design and test this type of numerical simulator, allowing to identify some breakpoints in these simulator projects before its delivery. These integrations present successful results, eliminating interface errors and failures, improvements in human-computer interactions and, consequently, it contributes perform a faster procedure to develop an interface for an electromagnetic simulator, which can be applied in science and didactic procedures.

RFID in the central warehouse of refundable uniforms Supply Sub Directorate

This work aims to analyze the effect caused by the implementation of logistics automation project in the process of separation uniform refundable in SDAB (Supply Sub Directorate), between the years 2010 and 2012. The research used as the source database of Integrated Supply System (SIA), intended to check the performance of separation before and after implementation of the automation project. The data stored in SIA were analyzed following the method of the indicator OTIF (On Time In Full). The result showed that the automation project has increased the logistics performance of separation of uniforms from 69% to 100%. The analysis confirmed that the combination of technology of stacker with the radio frequency identification of products (RFID) used in the SDABs automation project, represents the possibility of obtaining performance values above the best market practices.

Evolutionary strategy algorithm applied to optimize micro-to-nano coupler devices

This work presents the integration of finite element method and artificial intelligence approaches to model and optimize non-intuitive micro-to-nano couplers. The non-intuitive term is related to the columns arrangements into the photonic couplers, which best optimized solution coupled 73.94%. Another important advantage is the possibility to fabricate this device into Unicamp facilities.

Towards an integrated evolutionary strategy and artificial neural network computational tool for designing photonic coupler devices

Abstract Photonics has been widely explored in computing and communications, mainly to rationalize the relationship between device size minimization and data processing/transmission maximization. Generally driven by optimization and modeling techniques, the design of photonic devices is often performed by bio-inspired algorithms integrated to electromagnetic solvers, which have achieved advances but is still time-consuming. As an alternative to a costly finite element method (FEM) solver, a multilayer perceptron (MLP) neural network is proposed for computing power coupling efficiency of photonic couplers, originally designed through an integrated evolutionary strategy (ES) and FEM routine. We address the ES-FEM design of two efficient couplers, present the MLP implementation and the MLP training and testing over the routine generated datasets, and measure MLP and FEM runtime. MLP suitably predicted the power coupling efficiency of a variety of unknown couplers on tests. The measured runtime showed MLP is ∼105 faster than FEM. In conclusion, MLP is a potential tool to be integrated to ES on the design of such photonic couplers.

Development of a computational environment for MIT electromagnetic equation propagation simulator

In this work, a high-level computational environment has been developed for the MIT Electromagnetic Equation Propagation (MEEP) software. Pre-processing and post-processing features have been implemented through the Visualization Toolkit (VTK) framework, in order to provide new graphical features for MEEP. An interactive user interface is available to make a scripting-free MEEP usage. Software engineering techniques have been employed in order to provide a reusable, maintainable, extendable, and integrable software system. Tests show an elaborate electromagnetic simulation scenario in the pre-processing stage, as well as bi-dimensional movies and interactive three-dimensional plan cuts in the post-processing phase.