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25th AIAA/CEAS Aeroacoustics conference

作者： Jo, Yeongmin Jardin, Thierry Gojon, Romain Jacob, Marc C. Moschetta, Jean-Marc Univ Toulouse ISAE SUPAERO Dept Aerodynam Energet & Prop DAEP Toulouse France

ISBN: (数字)9781624105883

ISBN: (纸本)9781624105883

The demand of micro air vehicles (MAV) with multiple rotors is increasing in both military and civil applications because of their versatility on various missions. However, the use of MAVs for some missions still has limited success because of their noise pollution. One of the main noise sources is aeroacoustic sound produced by the low Reynolds number flows around the rotors. There have been many previous studies about small-scale rotor systems of MAVs during the past decades, but they mainly focused on investigations of the aerodynamics rather than the acoustics. Several studies considering the acoustics have started recently. However, only steady loading forces computed by using Blade Element Momentum theory (BEMT) were considered in the previous studies, and the noise from unsteady flow phenomena were not taken into account. The main objective of the current study is to investigate the noise mechanisms and further to find ways to reduce the noise levels in unsteady low Reynolds number flows. A Non-linear Vortex Lattice Method (NVLM) is used to simulate the unsteady low Reynolds number flow and model the corresponding noise sources. The tonal components of far-field noise is predicted by using an acoustic analogy based on Ffowcs Williams-Hawkings (FW-H) equations. These numerical methods are applied to low Reynolds number propeller and rotor cases, and validated upon experimental data. Then, they are used to investigate the influence of the number of blades on both aerodynamic and aeroacoustic performance and provide further insight into prominent sources of noise.

关键词： Detached Eddy Simulation Blade Passing Frequency Propellers Micro Air Vehicle Aerodynamic Flows Blade Loading Acoustics Blade Element Momentum theory Overall Sound Pressure Level Aerodynamic Performance

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linear algebra Applied to Kinematic Control of Mobile Manipulators 1

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iCatse International conference on IT Convergence and Security (ICITCS)

作者： Andaluz, Victor H. Sasig, Edison R. Chicaiza, William D. Velasco, Paola M. Univ Fuerzas Armadas ESPE Sangolqui Ecuador

ISBN: (数字)9789811064517

ISBN: (纸本)9789811064517;9789811064500

This paper is focused in linear algebra theory applied to control of mobile manipulator robots. In order to design the control algorithm, the kinematic system is approximated using numerical methods. Then, the optimal control actions are obtained through linear algebra approach. The structure of the controller consists in two solutions;a particular solution that allow following the desired trajectory and a homogeneous solution that allow performing secondary objectives as maximum manipulability and avoid static obstacles. In addition, the stability analysis is demonstrated through linear algebra concepts where it is shown that the tracking error tends asymptotically to zero. Finally, experimental results show the effective of proposed control algorithm over the mobile manipulator robot AKASHA.

关键词： linear algebra numerical methods Controller design Model Mobile manipulator

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Suboptimal adaptive control of dynamic systems with state constraints based on Barrier Lyapunov functions

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IET CONTROL theory AND applications 2018年第8期12卷 1116-1124页

作者： Salgado, Ivan Mera, Manuel Chairez, Isaac Inst Politecn Nacl Ctr Innovac & Desarrollo Tecnol Computo Mexico City DF Mexico Inst Politecn Nacl Escuela Super Ingn Mecan & Elect Unidad Ticoman Mexico City DF Mexico Inst Politecn Nacl Unidad Profes Interdisciplinaria Biotecnol Mexico City DF Mexico

This study designed a suboptimal output control strategy to characterise an attractive and invariant set for the state trajectories of perturbed linear systems with noisy measurements and state constraints. The state constraints were defined by a given polytope formed of by n-dimensional vectors. An adaptive linear controller enforced the existence of an attractive and invariant set (centred at the origin) for the trajectories of the perturbed system. A barrier Lyapunov function (BLF) and the attractive ellipsoid method (AEM) derived the adjustment law of the adaptive gain. The controller design used the linear matrix inequality technique to solve two optimisation problems. The first solution provided a maximal set where the initial conditions must belong without violating the state constraints. The second optimisation solution characterised the invariant minimal attractive set for the system trajectories. An academic example verified how the proposed adaptive control generated the system trajectories that converged to the minimal attractive ellipsoid while keeping them inside the polytope defining the state constraints. The simulation script showed the advantages of the adaptive BLF controller (ABLC) against classical AEM controller. A second numerical example considered a direct current motor showing the advantages of the ABLC against the sliding mode technique.

关键词： adaptive control state constraints optimisation problems Stability in control theory dynamic systems adaptive BLF controller linear systems algebra suboptimal output control strategy Lyapunov methods Self-adjusting control systems linear matrix inequality technique suboptimal adaptive control adaptive linear controller Optimal control linear matrix inequalities attractive ellipsoid method perturbed linear systems barrier Lyapunov functions optimal control

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21st International Workshop on Computer algebra in Scientific Computing, CASC 2019

21st International Workshop on Computer Algebra in Scientifi...

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21st International Workshop on Computer algebra in Scientific Computing, CASC 2019

ISBN: (纸本)9783030268305

The proceedings contain 30 papers. The special focus in this conference is on Computer algebra in Scientific Computing. The topics include: About Integrability of the Degenerate System;construction of a New Implicit Difference Scheme for 2D Boussinesq Paradigm Equation;symbolic Investigation of the Dynamics of a System of Two Connected Bodies Moving Along a Circular Orbit;parametric Standard Bases and Their applications;an Algorithm for Computing Coefficients of Words in Expressions Involving Exponentials and Its Application to the Construction of Exponential Integrators;revisit Sparse Polynomial Interpolation Based on Randomized Kronecker Substitution;root-Finding with Implicit Deflation;on linear Invariant Manifolds in the Generalized Problem of Motion of a Top in a Magnetic Field;robust Schur Stability of a Polynomial Matrix Family;symbolic and numerical methods for Searching Symmetries of Ordinary Differential Equations with a Small Parameter and Reducing Its Order;towards Soft Exact Computation (Invited Talk);an Algorithm for Computing Invariant Projectors in Representations of Wreath Products;PAF Reconstruction with the Orbits Method;analytic Complexity of Hypergeometric Functions Satisfying Systems with Holonomic Rank Two;on Explicit Difference Schemes for Autonomous Systems of Differential Equations on Manifolds;on Berlekamp–Massey and Berlekamp–Massey–Sakata Algorithms;an Algorithm for Solving a Quartic Diophantine Equation Satisfying Runge’s Condition;old and New Nearly Optimal Polynomial Root-Finders;symbolic-Numeric Implementation of the Four Potential Method for Calculating Normal Modes: An Example of Square Electromagnetic Waveguide with Rectangular Insert;a Divergence-Free Method for Solving the Incompressible Navier–Stokes Equations on Non-uniform Grids and Its Symbolic-Numeric Implementation.

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Networked filtering with Markov transmission delays and packet disordering

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IET CONTROL theory AND applications 2018年第5期12卷 687-693页

作者： Liu, Andong Zhang, Wen-an Chen, Bo Yu, Li Zhejiang Univ Technol Dept Automat Hangzhou Zhejiang Peoples R China Nanyang Technol Univ Sch Elect & Elect Engn Singapore Singapore

This is concerned with the filtering problem for a class of networked systems with Markov transmission delays and packet disordering. The transmission delays are considered to be a Markov chain with finite states, and a packet reordering mechanism is proposed to deal with the packet disordering. According to the original transition probability matrix of Markov delays, a new method is developed to calculate the reordered transition probability matrix. A sufficient condition is derived such that the filtering error system is exponentially stable in the mean-square sense. Moreover, an optimal filter is designed by solving a convex optimisation problem. An illustrative example is provided to show the effectiveness of the proposed filtering method.

关键词： Signal processing theory Optimisation techniques filtering theory finite states convex programming probability packet reordering mechanism convex optimisation problem filtering error system exponential stability Markov chain networked filtering Markov delays matrix algebra packet disordering Markov transmission delays original transition probability matrix linear algebra (numerical analysis) delays networked systems mean square error methods Interpolation and function approximation (numerical analysis) Filtering methods in signal processing reordered transition probability matrix Markov processes optimal filter asymptotic stability

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Autonomous Monitoring of Air Quality Through an Unmanned Aerial Vehicle 32nd

Autonomous Monitoring of Air Quality Through an Unmanned Aer...

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32nd International conference on Industrial, Engineering and Other applications of Applied Intelligent Systems (IEA/AIE)

作者： Andaluz, Victor H. Chicaiza, Fernando A. Cuzco, Geovanny Carvajal, Christian P. Ortiz, Jessica S. Morales, Jose Morales, Vicente Sarzosa, Darwin S. Mora-Aguilar, Jorge Andaluz, Gabriela M. Univ Fuerzas Armadas ESPE Sangolqui Ecuador Univ Nacl Chimborazo Riobamba Ecuador Escuela Super Politecn Chimborazo Riobamba Ecuador Univ Tecn Ambato Ambato Ecuador Univ Int Ecuador Quito Ecuador

ISBN: (纸本)9783030229993;9783030229986

The monitoring of air quality allows to evaluate the amount of harmful particles for health that are being released. Under this paradigm and knowing the current methods to monitor these parameters, this work proposes the use of a UAV for commercial use and the construction of a card for gas measurement. Additionally and with the objective of having complete control over the vehicle, the article proposes the development of a library for the control and monitoring of the instrumentation of a commercial drone, through which the validation of control algorithms is proposed. As a result of this work, two real experiments on a rural environment and an urban environment are carried out to validate both the library created and the method of acquiring information on air quality.

关键词： Air quality UAV linear algebra Advanced controller

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Non-linear model-order reduction based on tensor decomposition and matrix product

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IET CONTROL theory AND applications 2018年第16期12卷 2253-2262页

作者： Li, Zhen Jiang, Yaolin Xu, Kangli Xinjiang Univ Coll Math & Syst Sci Urumqi 830046 Peoples R China Xi An Jiao Tong Univ Sch Math & Stat Xian 710049 Shaanxi Peoples R China

In this study, based on tensor decomposition and matrix product, the authors investigate two model-order reduction (MOR) methods for the quadratic-bilinear (QB) systems which are equivalently transformed from the non-linear input-output systems. Since the quadratic term coefficient of the QB system can be considered as the matricisation of a tensor, they propose two computationally efficient ways to obtain the reduced system by using tensor calculus. First, the Tucker decomposition of tensors is used to deal with the quadratic term coefficient of the QB system. The transformational matrix is constructed by applying the analysis of matrix product. Then, they get the reduced QB system which can match the first several expansion coefficients of the original output. Besides, they propose another MOR method based on the CANDECOMP/PARAFAC decomposition. These two methods can avoid large computational complexity in the process of computing the reduced system. Moreover, the error estimation and stability of the authors' MOR methods are discussed. The efficiency of their MOR methods is illustrated by two numerical examples and they show their competitiveness when compared to the proper orthogonal decomposition method.

关键词： matrix algebra reduced order systems tensors nonlinear model-order reduction tensor decomposition matrix product quadratic-bilinear systems nonlinear input-output systems quadratic term coefficient tensor calculus transformational matrix reduced QB system expansion coefficients MOR method CANDECOMP PARAFAC decomposition orthogonal decomposition method Tucker decomposition

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Privacy-Preserving Predictive Model Using Factor Analysis for Neuroscience applications 5

Privacy-Preserving Predictive Model Using Factor Analysis fo...

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5th IEEE Int Conf on Big Data Security on Cloud (BigDataSecurity) / 5th IEEE Int Conf on High Performance and Smart Computing (IEEE HPSC) / 4th IEEE Int Conf on Intelligent Data and Security (IEEE IDS)

作者： Kundu, Suprateek Suthaharan, Shan Emory Univ Dept Biostat & Bioinformat Atlanta GA 30322 USA UNC Greensboro Dept Comp Sci Greensboro NC 27407 USA

ISBN: (纸本)9781728100067

The purpose of this article is to present an algorithm which maximizes prediction accuracy under a linear regression model while preserving data privacy. This approach anonymizes the data such that the privacy of the original features is fully guaranteed, and the deterioration in predictive accuracy using the anonymized data is minimal. The proposed algorithm employs two stages: the first stage uses a probabilistic latent factor approach to anonymize the original features into a collection of lower dimensional latent factors, while the second stage uses an optimization algorithm to tune the anonymized data further, in a way which ensures a minimal loss in prediction accuracy under the predictive approach specified by the user. We demonstrate the advantages of our approach via numerical studies and apply our method to high-dimensional neuroimaging data where the goal is to predict the behavior of adolescents and teenagers based on functional magnetic resonance imaging (fMRI) measurements.

关键词： factor models data privacy neuroimaging Data privacy Neuroimaging Privacy Factor analysis Optimization algorithms fMRI anonymised data Prediction models Predictive Neurosciences Neurophysiology Teens

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An Empirical Evaluation of Sketching for numerical linear algebra 18

An Empirical Evaluation of Sketching for Numerical Linear Al...

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24th ACM SIGKDD conference on Knowledge Discovery and Data Mining (KDD)

作者： Dahiya, Yogesh Konomis, Dimitris Woodruff, David P. IIT Kanpur Kanpur Uttar Pradesh India CMU Pittsburgh PA USA

ISBN: (纸本)9781450355520

Over the last ten years, tremendous speedups for problems in randomized numerical linear algebra such as low rank approximation and regression have been made possible via the technique of randomized data dimensionality reduction, also known as sketching. In theory, such algorithms have led to optimal input sparsity time algorithms for a wide array of problems. While several scattered implementations of such methods exist, the goal of this work is to provide a comprehensive comparison of such methods to alternative approaches. We investigate least squares regression, iteratively reweighted least squares, logistic regression, robust regression with Huber and Bisquare loss functions, leverage score computation, Frobenius norm low rank approximation, and entrywise l(1)-low rank approximation. We give various implementation techniques to speed up several of these algorithms, and the resulting implementations demonstrate the tradeoffs of such techniques in practice.

关键词： Logistic Regression Low Rank Approximation Regression Robust methods Sketching

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Geometric algebra, Extended Cross-Product and Laplace Transform for Multidimensional Dynamical Systems

Geometric Algebra, Extended Cross-Product and Laplace Transf...

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conference on Computational methods in Systems and Software (CoMeSySo)

作者： Skala, Vaclav Univ West Bohemia Fac Appl Sci Dept Comp Sci & Engn Plzen Czech Republic

ISBN: (纸本)9783319676180

This contribution describes a new approach for solving linear system of algebraic equations and differential equations using Laplace transform by the extended-cross product. It will be shown that a solution of a linear system of equations Ax = 0 or Ax = b is equivalent to the extended cross-product if the projective extension of the Euclidean system and the principle of duality are used. Using the Laplace transform differential equations are transformed to a system of linear algebraic equations, which can be solved using the extended cross-product (outer product). The presented approach enables to avoid division operation and extents numerical precision as well. It also offers applications of matrix-vector and vector-vector operations in symbolic manipulation, which can leads to new algorithms and/or new formula. The proposed approach can be applied also for stability evaluation of dynamical systems. In the case of numerical computation, it supports vector operation and SSE instructions or GPU can be used efficiently.

关键词： linear system of equations linear system of differential equations Laplace transform Extended cross product Outer product Homogeneous coordinates Duality Geometrical algebra Dynamic systems Stability GPGPU computation SSE instructions

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