Articles — Project / Lab Report

This work is going to analyze the Forced Van Der Pol's Equation which is used to analyze the electric circuit. In 1927, Balthasar Van Der Pol observed the stable oscillation and heard some irregular noise in vacuum tube circuit. He then proposed the Forced Van Der Pol's Equation to analyze the circuit and suggested the concept of limit cycle and Chaos to explain his observation. In this work, We would like to analyze behavior of the model by observing the phase space, time series, bifurcation diagram and power spectrum. Those points in the figures are calculated by Runge-Kutta Method with the aid of MATLAB. For a better understanding, the RLC circuit, which is a electric circuit consisting the a resistor, an inductor and a capacitor, will be used as an example for explaining the properties. Apart from electric circuit, the Forced Van Der Pol's Equation can be applied to dynamic systems in different aspect, such as the artificial heart, economic market and so on. Therefore, we suggest this work to all students since the Forced Van Der Pol's Equation can be applied to many majors, like Mathematics, Physics, Economics, Sociology, Biology, Engineering and so on.

In most corruption scandals, the use of front companies for money laundering is almost ubiquitous. This work proposes to apply image classification to detect such organizations, through the use of Convolutional Neural Networks (CNN), namely the AlexNet architecture. The images are obtained by address search in Google Street View API, and the resulting classification will be further used along with other features to detect front com- panies in order to help the auditors from the Ministry of Transparency and Office of the Comptroller General (CGU, in Portuguese). To this moment, we applied classification to almost 15 thousand suppliers scenes with active contracts with the Brazilian Government until September 2016, obtained through data matching between the Government Purchases database and the Brazilian Federal Revenue Office database (more recent scenes should be added as this work progresses). Preliminary results with a pre-trained AlexNet CNN show the need for developing new scene classes more suited to the Brazilian context. In order to do this, we propose to apply clustering algorithms in features extracted from the last fully-connected layer of this net. The classes obtained will be used to fine-tune the AlexNet CNN for future classification, through the use of training from scratch or fine tuning techniques.

Prática 9 de Tópicos de Física - CEFET

Artigo de pesquisa

Se realizaron las correspondientes mediciones según lo que se pedía en la práctica, esto para comprobar la resistencia en un circuito paralelo de manera calculada y otra midiéndola en un circuito real. Se midió el valor de diversas resistencias observando el código de color y después de esto se midieron 10 resistencias iguales con un óhmetro para comprobar sus valores y de todos los procedimientos se saco el error absoluto, relativo y su porcentaje.

The purpose of this lab was to illustrate the validity of the law of conservation of energy along with the determination of the spring constant of a given spring. For the first part the spring constantk was to be found from a given spring. Through the suspension of various known metal masses on a vertically suspended spring, the spring constant was determined. Two methods were used: the algebraic rearrangement of Hooke's Law and a slope analysis of a linear regression on a Force (N) against Stretch Length (m) scatter plot. The spring constant k was determined to be 26.438 ± 1.063. For the second part of the lab, the aim was to validate the law of conservation of energy through the oscillation of a vertically suspended spring. Data was collected using a Vernier Motion Detector 2 machine and the various energies (kinetic energy, gravitational potential energy and spring potential energy) were collected and summed up. The sum of these energies yielded a fairly constant energy total (2.287 J ± 0.025 J) which supports the authenticity of the law of conservation of energy. While there were some uncertainties due to the lab setup, human error and equipment error it did not affect the validity of the methods during experimentation. Overall, the spring constant k of a given spring was determined and the law of conservation of energy was validated through the calculation of total energy during a suspended mass' oscillation.

This project will discuss the usage of the logical programming language called Prolog to solve a diabolic magic squares made with 4 by 4 squares and Python as a front-end. A diabolic magic squares are matrix of 4 rows and 4 columns which have unique numbers on each cell from 1 to 16. This project will implement the solution of this problem using logical deduction.

Minería de datos con Weka para la predicción del precio de automóviles de segunda mano

Este artigo tem como objetivo relatar e detalhar a construção de um conversor buck-boost. Cuja a função deste é converter uma tensão cc (corrente contínua) de entrada, em outra tensão cc em sua saída, de valor mais elevado ou inferior dependendo de sua configuração. Destaca-se aqui o uso de um semi condutor MOSFET que funciona como uma chave controladora. Na elabiração deste está destacada o funcionamento, principais características e toda a parte de simulação e comprovação prática deste conversor.