Murilo Teixeira Silva

C-CORE · Systems

Term Paper for the Physical Oceanography course. Review of the JONSWAP and PM wave models

This paper proposes the use of a nonlinear inversion technique for the extraction of the directional ocean wave spectrum from bistatic high-frequency surface wave radar (HFSWR) Doppler data. The extraction method is combined with nonlinear regression expressions, solely based on the Doppler data, to retrieve wind speed and direction. Once the initi...

A system of equations for calculating the electric field in curvilinear coordinates without imposing external boundary conditions is proposed. First, the system of equations is derived using generalized functions, without imposing external boundary conditions or a coordinate system. Then, in order to demonstrate the use of the system of equations,...

A correction term for electromagnetic scattering from the ocean surface with large roughness scales in the HF band is proposed. A generalized functions method has been employed to obtain the operator equation of the electric field over the ocean surface. Using a dipole antenna with a pulsed sinusoidal signal at the transmitter, and employing Fourie...

The present work shows the derivation of general forms for the expressions of the first- and second-order corrections to the radar cross-section (RCS) of the ocean surface at electromagnetically-high sea states. An analysis of the morphology of the correction terms and their impact on the total RCS of the ocean surface is presented. It is shown tha...

An extension to the correction theory for the electric field and radar cross-section of the ocean surface under electromagnetically-high sea states is presented, accounting for the impact of second-order hydrodynamic interaction of waves on the total radar cross-section of the ocean surface in this case. An expression for the second-order correctio...

The scattering theory developed in the past decades for high-frequency radio oceanography has been restricted to surfaces with small heights and small slopes. In the present work, the scattering theory for bistatic high-frequency radars is extended to ocean surfaces with arbitrary wave heights. Based on recent theoretical developments in the scatte...

This work presents the use of a nonlinear autoregressive neural network to obtain an improved estimate of sea surface winds, taking Placentia Bay, Newfoundland and Labrador, Canada, as a study case. The network inputs and delays were chosen through cross correlation with the target variable. The proposed method was compared with five other wind spe...

An alternative analytical solution to six degrees-of-freedom position and attitude estimation problem is proposed. The proposed method relies on the use of Singular Value Decomposition to the transformation matrix between the currents in the transmitter and in the receiver. The proposed method is validated using synthetic data, in which a random mo...

Knowledge of the ocean wave spectrum, from which many important ocean parameters can be extracted, is crucial to understand the ocean’s behaviour. Due to the intricate nature of ocean wave spectrum extraction from HF radar data, previously devised methods relied on making a linear approximation to the original nonlinear problem or resorted to const...

The use of Self-Organizing Map (SOM) algorithm for feature extraction and dimensionality reduction applied to underwater object detection with Low Frequency Electromagnetic Waves is presented. Computer simulation is used to generate a direct model for the study region, and a Self Organizing Map Algorithm is used to fit the data and return a similar...

The Finite Element Method (FEM) simulation of the scattering of a Transverse Electric (TE) mode frequency domain electromagnetic plane wave within VHF range over models for coastal and inland regions is presented. The amplitude of the electric field on the different media for each model and the effects these media on electromagnetic propagation are...

Presentation at the II Mining Warfare Symposium (2013)

A simulação computacional através de métodos numéricos é uma área importante para a Engenharia, possibilitando o desenvolvimento tecnológico sem o uso direto de protótipos físicos. Para a realização de simulações são utilizadas equações diferenciais, as quais descrevem o comportamento de estruturas submetidas a fenômenos complexos. A Equação de Poi...