661 research outputs found

    Maximum likelihood parameter estimation for linear systems with singular observations

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    It is shown that maximum likelihood estimation of unknown parameters of a linear system with singular observations in general results in the maximization of a likelihood function subject to equality constraints

    Polynomial solution of the standard H2 problem

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    A polynomial solution to the standard linear H2 problem is given, together with a detailed algorithm. The assumptions are very general and the paper includes necessary and sufficient conditions for the existence of a solution

    Relation between growth dynamics and the spatial distribution of intrinsic defects in self-assembled colloidal crystal films

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    Herein we establish a clear relation between the parameters that govern the growth dynamics and the structural quality of colloidal crystal films. We report an optical analysis of the spatial distribution of intrinsic defects in colloidal crystal films and correlate our results with a theoretical model describing the growth dynamics of such lattices. We find that the amount of defects fluctuates periodically and decreases along the growth direction of the lattice. We demonstrate that these spatial variations are a direct consequence of the temporal oscillations of the crystal film formation velocity, which are inherent to the colloidal particle deposition process. © 2008 American Institute of Physics.Peer Reviewe

    A state space algorithm for the spectral factorization

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    This paper presents an algorithm for the spectral factorization of a para-Hermitian polynomial matrix. The algorithm is based on polynomial matrix to state space and vice versa conversions, and avoids elementary polynomial operations in computations; It relies on well-proven methods of numerical linear algebra such as Schur decomposition

    Asymptotic root loci of multivariable linear optimal regulators

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    The maximally achievable accuracy of linear optimal regulators and linear optimal filters

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    Robust Aeroelastic Control of Very Flexible Wings using Intrinsic Models

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    This paper explores the robust control of large exible wings when their dynamics are written in terms of intrinsic variables, that is, velocities and stress resultants. Assuming 2-D strip theory for the aerodynamics, the resulting nonlinear aeroelastic equations of motion are written in modal coordinates. It is seen that a system which experiences large displacements can nonetheless be accurately described by a system with only weak nonlinear couplings in this description of the wing dynamics. As result, a linear robust controller acting on a control surface is able to effectively provide gust load alleviation and flutter suppression even when the wing structure undergoes large deformations. This is numerically demonstrated on various representative test cases. © 2013 by Yinan Wang, Andrew Wynn and Rafael Palacios
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