# Articles — Recent

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Pérdidas de energía por fricción
se presenta el desarrollo de un algoritmo bajo código fuente JavaScript para la solución de la ecuación de flujo crítico (2). Se implementó un lenguaje de programación orientado a objetos para sistemas Android 4.0 o superiores a partir de procesos iterativos e incrementales (Desarrollo ágil). Se utilizó el método numérico de Newton-Raphson para determinar la profundidad crítica de sietes secciones hidráulicas (Rectangular, trapezoidal, trapezoidal asimétrico, triangular, triangular asimétrico, parabólico y circular). Con el propósito de acelerar y garantizar el nivel de convergencia para cada una de las secciones se obtuvo una función potencial para establecer el valor semilla en el proceso iterativo, este valor se asocia de manera directa a las condiciones preestablecidas del problema hidráulico. La aplicación calcula la profundidad crítica, velocidad crítica, área
The Parallelization and Optimization of the N-Body Problem using OpenMP and Cuda
This research paper aims at exploiting efficient ways of implementing the N-Body problem. The N-Body problem, in the field of physics, predicts the movements and planets and their gravitational interactions. In this paper, the efficient execution of heavy computational work through usage of different cores in CPU and GPU is looked into; achieved by integrating the OpenMP parallelization API and the Nvidia CUDA into the code. The paper also aims at performance analysis of various algorithms used to solve the same problem. This research not only aids as an alternative to complex simulations but also for bigger data that requires work distribution and computationally expensive procedures.
Tushaar Gangarapu
A Psychology Lab Manual
Created by John Paul Minda, PhD Professor of Psychology The Brain and Mind Institute The University of Western Ontario London, ON N6A 5C2 Version 1.2 Feb 13, 2018
John Paul Minda
Controle digital de um conversor CC-CC
Um artigo sobre controle digital de conversores CC-CC tipo buck utilizando microcontrolador STM cortex-m0+.
Ana Caroline Tondo Bonafim, Jefferson Willian França Góes, Raul Scarmosin Freitas
Evolutionary Language Development in Multi-Agent Cooperative Learning Games
Lazaridou., et al 2017 proposed a framework for language learning that relies on multi-agent communication. The agents in the framework were setup in a referential game where they communicated about many images. In this paper, we propose an experiment where agents develop a private language for referring to specified sentences given a set of sentences. The challenge is for the agents to learn a method of distinguishing differences between sentences and to develop a shared language to be able to refer to particular sentences by those distinguishing features. We will evaluate the agents' ability to accurately identify and differentiate the sentences. In addition, we will identify patterns in the methods that the agents develop to refer to the different types of sentences.Keywords: Reinforcement learning, multi-agent coordination
Eric Tsai
SOLAR SALES ON YOUR TRIP TO MARS
We study Logarithmically Spiral Trajectories and, in particular, we look for a solution to minimize the transit time of a Spacecraft propelled by a Solar Sail, while simultaneously minimizing the area of the Solar Sail, which would allow us to carry more payload on board. We start by analyzing the forces that act on the Spacecraft taking into account that its propellant is a Solar Sail; we use the studied forces to deduce the motion equations. We then solve this motion equation with a Runge-Kutta 4 method and transform the problem of minimizing time and area to a Non-linear Optimization problem. When solving the NLP we also try to minimize the relative final speed of th spacecraft with the destination planet in order to guarantee the possibility of a safe landing on its surface. The model improves when an angle parameter α (describing the angle formed by the Solar Sail with the colliding photons) is defined as a piecewise constant function and optimized whose values are optimized in every interval to minimize transit time and Area. Using the developed model to optimize the trajectory to be followed for sending from Earth to Mars a 2000kg-spacecraft propelled by a Solar Sail, subject to the condition that at trajectory start Mars and Earth were at their closest approach, and the Arrival Relative Velocity is less than 9km/s, give us a minimal transit time of 500days and a minimal area for the Solar Sail of 183158m2, meaning that the maximal payload would be 718kg. Compared with different number of partitions of α, the optimum stays stable. This gives a solid optimal trajectory and a great result for the numerical method used. Actually, waiting until the best moment to throw the Spacecraft, id est, Mars is at 1.14 radians respectively to Earth initial position, the minimal sail area 145950 m2 and, therefore, ables to transport until 978 kg of payload with the same transit time. In addition and to conclude we tried the model to optimize the inverse trajectory.
Marco Praderio Bova, Eneko Martin Martinez, & Maria dels Àngels Guinovart Llort
Sinds enkele jaren ben ik op zoek naar eenvoudige wiskundige en fysische problemen die onverwacht gerelateerd zijn met het getal $$\pi$$. In The bouncing balls and pi beschreef ik eerder al hoe de opeenvolgende decimalen van $$\pi$$ kunnen berekend worden door twee ballen volledig elastisch tegen elkaar en tegen een muur te laten botsen. In dit artikel zal ik aantonen hoe het getal $$\pi$$ tevoorschijn komt door een oneindige serie rechthoeken met oppervlakte 1 spiraalsgewijze aan elkaar te kleven. In een veralgemening van dit probleem duikt op een natuurlijke wijze de gammafunctie en de formule van Stirling op.