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25th IEEE International Parallel and Distributed Processing Symposium, Workshops and Phd Forum, IPDPSW 2011

作者： Da Luz, Eduardo Fávero Pacheco Becceneri, José Carlos De Campos Velho, Haroldo Fraga Post-Graduation Program in Applied Computing National Institute for Space Research São José dos Campos/SP Brazil Computing and Applied Mathematics Associated Laboratory National Institute for Space Research São José dos Campos/SP Brazil

ISBN: (纸本)9780769543857

The Multiple Particle Collision Algorithm (MPCA) is a nature-inspired stochastic optimization method developed specially for high performance computational environments. Its advantages resides in the intense use of computational power provided by multiple processors in the task of search the solution space for a near optimum solution. This work presents the application of MPCA in solving two inverse problems written as optimization problems, its advantages and disadvantages are also described, so are the obtained results. © 2011 IEEE.

关键词： Inverse problems

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Climate Precipitation Prediction by Neural Network

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Journal of mathematics and System Science 2015年第5期5卷 207-213页

作者： Juliana Aparecida Anochi Haroldo Fraga de Campos Velho Applied Computing Graduate Program National Institute for Space Research (INPE) Brazil. Associated Laboratory for Computing and Applied Mathematics National Institute for Space Research (INPE).

In this work a neural network model for climate forecasting is presented. The model is built by training a neural network with available reanalysis data. In order to assess the model, the development methodology considers the use of data reduction strategies that eliminate data redundancy thus reducing the complexity of the models. The results presented in this paper considered the use of Rough Sets Theory principles in extracting relevant information from the available data to achieve the reduction of redundancy among the variables used for forecasting purposes. The paper presents results of climate prediction made with the use of the neural network based model. The results obtained in the conducted experiments show the effectiveness of the methodology, presenting estimates similar to observations.

关键词： Climate Prediction Neural Networks Rough Sets Theory

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Optimization methods applied to nonlinear signal interference models 4

Optimization methods applied to nonlinear signal interferenc...

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4th International Conference on Engineering Optimization, ENGOPT 2014

作者： da Silva, M. Senne, E.L.F. Vijaykumar, N.L. Applied Computing INPE - National Institute for Space Research São José dos Campos Brazil Department of Mathematics UNESP - São Paulo State University Guaratinguetá Brazil Associated Laboratory of Computational Mathematics INPE - National Institute for Space Research São José dos Campos Brazil

ISBN: (纸本)9781138027251

In wireless mesh networks, it is important to establish the transmission capacity of the links, taking into account the presence of noise that interferes with the transmission and consequently degrades the signal sent from one device to another. This signal degradation is calculated from interference models, such as SNR (Signal-to-Noise Ratio), SIR (Signal-to-Interference Ratio) and SINR (Signal-to-Interference-plus-Noise Ratio). In these models, the link capacity is calculated according to a decreasing of power levels, depending on the noise or interference present, which needs to be adjusted to acceptable levels, in order to avoid committing the signal emission besides not causing health damage to people close to the device. Different models can be used to estimate the noise present in an environment. In wireless transmission, however, it is possible to calculate the noise by means of nonlinear equations, which are able to estimate the interference levels present in the network links. From these elements, it is possible to maximize the capacity of the network links, using models of nonlinear programming. As these models are difficult to be solved analytically, this work compares the results of different nonlinear programming models, based on the main interference models, with the results obtained by a classical approach for solving nonlinear models: The simulated annealing metaheuristic. In this paper, it will analyze the behavior of the heuristic algorithm, regarding the quality of the solution obtained and the processing time, as the network size increases. © 2015 Taylor & Francis Group, London.

关键词： Nonlinear programming

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Multiple Particle Collision Algorithm applied to Radiative Transference and Pollutant Localization Inverse Problems

Multiple Particle Collision Algorithm Applied to Radiative T...

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IEEE International Symposium on Parallel and Distributed Processing Workshops and Phd Forum (IPDPSW)

作者： Eduardo F´vero Pacheco da Luz Jose Carlos Becceneri Haroldo Fraga de Campos Velho Applied Computing National Institute of Space Research (INPE) Sao Paulo Brazil Computing and Applied Mathematics Associated Laboratory National Institute of Space Research (INPE) Sao Paulo Brazil

关键词： Optimization Inverse problems Principal component analysis Mathematical model Absorption Atmospheric modeling Algorithm design and analysis

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A Committee of MLP with Adaptive Slope Parameter Trained by the quasi-Newton Method to Solve Problems in Hydrologic Optics

A Committee of MLP with Adaptive Slope Parameter Trained by ...

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International Joint Conference on Neural Networks

作者： Fabio Dall Cortivo Ezzat S. Chalhoub Haroldo F. Campos Velho Applied Computing Graduate Program (CAP) National Institute for Space Research (INPE) Sao Jose dos Campos Associated Laboratory for Computing and Applied Mathematics (LAC) National Institute for Space Research (INPE)

ISBN: (纸本)9781467314886

Artificial Neural Networks (ANNs) can be used to solve problems in Hydrologic Optics. A relevant problem is the estimation of the single scattering albedo and the phase function parameters, from the emitted radiation at the surface of natural waters. In this work we use a committee of ANNs of Multilayer Perceptron type to perform the estimation of the two mentioned parameters. The training of each network is formulated as a nonlinear optimization problem subject to constraints. In addition, each activation function has a distinct slope parameter, that is initially chosen by a random number generator function. This set of parameter (slopes) was included within the free variables network set in order to be adjusted to reach "optimal values", together with the weights and biases, during the network training. This procedure (slope parameters inclusion) makes each one of the activation functions to have a different slope. Each network that composes the committee was trained independently, in order to become expert for the estimation of only one of the hydrologic parameters. For the networks training, we used the quasi-Newton method that is implemented in E04UCF subroutine, in the NAG library, developed by the Numerical Algorithms Group - NAG. The use of the quasi-Newton method to train the networks together with the distinct slope parameters resulted in a network with a fast learning and excellent generalization. Once the networks were trained, they were grouped so to share the input patterns, but remained independent from one another. For the validation/generalization test we used two distinct sets. For all considered noise levels, we obtained 100% of correct answers for the first set, and above 90% of correct answers for the second set.

关键词： Artificial Neural Network Multilayer Perceptron Backpropagation Quasi-Newton Method Hydrologic Optics Phase Function Single Scattering Albedo Inverse Problems SLOPE FACTOR Newton method Slope parameter Artificial neural networks CSRP3 gene Network Optics hydrologic parameters Hydrology functional parameter Random Number Generators Activating function input mode

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Bred Vector for Analysis of Helicopter Main Rotor Dynamics

Bred Vector for Analysis of Helicopter Main Rotor Dynamics

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作者： Sumida, Ivana Yoshie de Campos Velho, Haroldo Fraga Ritto, Thiago Gamboa Aerospace Technology and Science Department Flight Test and Research Institute São José dos CamposSP Brazil Associated Laboratory for Computing and Applied Mathematics National Institute for Space Research São José dos CamposSP Brazil Department of Mechanical Engineering Federal University of Rio de Janeiro Rio de JaneiroRJ Brazil

The dynamics of helicopter main rotor is described by a highly nonlinear equations, and it is responsible to provide the sustentation of the rotorcraft. The representative frequency to this dynamics are associated to different regimes: unstable, periodic, and even chaotic behavior. The system responses are investigate performing several simulations under a set of numerical values of frequency. One important subject is to evaluate the goodness of the prediction of the simulated dynamics. The dynamical analysis is performed by bred vector approach. The breeding technique executes the model with a perturbed initial condition. The difference between the reference and the perturbed dynamics is called bred vector. The procedure can be employed systematically, producing a time series of bred vector. The bred vector magnitude is applied for addressing the predictability of the model, i.e., the degree of confidence from the simulation. © 2019, Springer Nature Switzerland AG.

关键词： Vectors

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Airplane ice accretion detection using parameter estimation

Airplane ice accretion detection using parameter estimation

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AIAA Guidance, Navigation, and Control Conference 2012

作者： Di Donato, Pedro F. A. Yoneyama, Takashi Macau, Elbert E. N. National Civil Aviation Agency - Brazil São José dos Campos SP Brazil Instituto Tecnológico de Aeronáutica São José dos Campos SP Brazil National Institute for Space Research São José dos Campos SP Brazil Aeronautical Product Certification Branch Brazil Electronic Engineering Department Brazil Associated Laboratory for Computing and Applied Mathematics Brazil

ISBN: (数字)9781600869389

ISBN: (纸本)9781600869389

While icing continues to be a major risk for aviation, pilots usually do not have a direct indication of the degradation of the airplane dynamic characteristics and control surfaces effectiveness due to the ice adhered to the airframe. Although icing detection based on its effects on airplane dynamics has been proposed using different approaches, these methods use inputs from several sensors which could be not available in simple airplanes. The objective of this work was to study the viability of ice accretion detection using measurements of a single output from airplane longitudinal dynamics usually available for autopilots. Parameter estimation was used in order to detect the changes on the system dynamic ARX model due to the ice accretion on the tailplane by comparing the estimated parameters with their expected values obtained from the airplane model. The results show that the proposed method can represent a way for implementing an alert that would increase crew awareness in case of aircraft icing. copy;2012 by Pedro F. A. Di Donato. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.

关键词： Ice

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A web service-based framework for temporal/spatial environmental data access

A web service-based framework for temporal/spatial environme...

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12th International Conference on Computational Science and Its Applications, ICCSA 2012

作者： Andrade, Rogério B. Nunes, Luiza Barbosa, Eduardo Batista De Moraes Vijaykumar, Nandamudi L. Dos Santos, Rafael Duarte Coelho Associated Laboratory for Computing and Applied Mathematics Brazilian National Institute for Space Research Av dos Astronautas 1.758 Jd. Granja São José dos Campos CEP 12227-010 SP Brazil Weather Forecast and Climate Studies Center Brazilian National Institute for Space Research SP-RJ Rodovia Presidente Dutra Km 40 Cachoeira Paulista CEP 12630-000 São Paulo Brazil

ISBN: (纸本)9780769547107

The Weather Forecast and Climate Studies Center (CPTEC) of the Brazilian National Institute for Space Research (INPE) is responsible for weather and climate forecasts and weather data collection and dissemination. Data is collected from several different systems and networks, with different sensors and features. Data is available through the Institute's web site through searchable web pages, which allows the easy retrieval of small amounts of information stored on the servers at a time, but only for a specific type of data (e.g. sensor). Although they serve their main purpose, these interfaces present limited usability: if an user needs to create a composite query involving different sensors or even different temporal/spatial slices of the data, this user will need to perform several queries while storing the intermediate results. In this paper we present a framework to access data and metadata stored in CPTEC's server that allows composition of complex queries through web services. These web services cover several different data sources, allowing the exploration of the data in ways not considered by the institute. Some simple case studies and first results are demonstrated. © 2012 IEEE.

关键词： Web services

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Design and development of a simulator for the Brazilian Data Collecting System based on satellites

Design and development of a simulator for the Brazilian Data...

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Simulation Winter Conference

作者： Germano Kienbaum Felipe Miranda Helcio Vieira Joaquim Barreto Marcus Cisotto Wanderson Almeida Associated Laboratory of Computing and Applied Mathematics National Space Research Institute Sao Jose dos Campos Brazil Technological Institute of Aeronautics General-Command for Aerospace Technology Sao Jose dos Campos Brazil Ground Segment Division National Space Research Institute Sao Jose dos Campos Brazil

This work describes an ongoing project, aiming at the development of a complete simulation study of the Brazilian Data Collecting System based on Satellites (SBCD). The SBCD system comprehends a spatial and a ground segment and it was built for automatic acquisition of data of meteorological and hydrological nature for use in environmental and business applications. The main objective of the project is to build a simulator for conducting a thorough analysis of the system, in order to assess its performance, to determine its best configuration and boundary conditions, and to optimize its operational cost and efficiency, in regard to different configurations and operating scenarios.

关键词： Satellites Analytical models Space technology Predictive models Cost function Data communication Virtual prototyping Computational modeling Aerospace simulation Performance analysis

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Global fire season severity analysis and forecasting

arXiv

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arXiv 2019年

作者： Ferreira, Leonardo N. Vega-Oliveros, Didier A. Zhao, Liang Cardoso, Manoel F. Macau, Elbert E.N. Associated Laboratory for Computing and Applied Mathematics National Institute for Space Research São José Dos Campos - SP Brazil School of Informatics Computing and Engineering Indiana University BloomingtonIN United States Department of Computing and Mathematics University of São Paulo Ribeirão Preto - SP Brazil Center for Earth System Science National Institute for Space Research Cachoeira Paulista - SP Brazil Institute of Science and Technology Federal University of São Paulo São José Dos Campos - SP Brazil

Fire activity has a huge impact on human lives. Different models have been proposed to predict fire activity, which can be classified into global and regional ones. Global fire models focus on longer timescale simulations and can be very complex. Regional fire models concentrate on seasonal forecasting but usually require inputs that are not available in many places. Motivated by the possibility of having a simple, fast, and general model, we propose a seasonal fire prediction methodology based on time series forecasting methods. It consists of dividing the studied area into grid cells and extracting time series of fire counts to fit the forecasting models. We apply these models to estimate the fire season severity (FSS) from each cell, here defined as the sum of the fire counts detected in a season. Experimental results using a global fire detection data set show that the proposed approach can predict FSS with a relatively low error in many regions. The proposed approach is reasonably fast and can be applied on a global scale. Copyright © 2019, The Authors. All rights reserved.

关键词： Climate change

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