Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- FINITE-DIMENSIONAL APPROXIMATIONS; INFINITE-DIMENSIONAL SYSTEMS; OPTIMAL HANKEL APPROXIMATION; BALANCED REALIZATION; DISCRETE FOURIER TRANSFORM (1)
- HAMILTONIAN MATRICES; EIGENVALUES; INVARIANT SUBSPACES; ALGEBRAIC RICCATI EQUATION (1)
- Sylvester equation; least squares; iterative; conjugate gradient (1)
Articles 1 - 5 of 5
Full-Text Articles in Engineering
Excessive Grain Boundary Conductivity Of Spin-Spray Deposited Ferrite/Non-Magnetic Multilayer, Yun Xing, J. Myers, Ogheneyunume Obi, Nian X. Sun, Yan Zhuang
Excessive Grain Boundary Conductivity Of Spin-Spray Deposited Ferrite/Non-Magnetic Multilayer, Yun Xing, J. Myers, Ogheneyunume Obi, Nian X. Sun, Yan Zhuang
Electrical Engineering Faculty Publications
Magnetic materials with a high self-biased ferromagnetic resonance (FMR) frequency and low electrical conductivity hold great potential for RF/microwave devices. In this work, ferrite film consisting of Fe3O4 (1.2 mu m)/photoresist (60 nm)/Fe3O4 (1.2 mu m) was deposited at 90 degrees C via spin spray deposition. Broadband impedance imaging with nanometer spatial resolution was recorded by using scanning microwave microscopy. Compared to a reference sample, it turned out that the grain boundary appeared to be more conductive than the grain.
Signal Classification In Fading Channels Using Cyclic Spectral Analysis, Eric Like, Vasu D. Chakravarthy, Paul Ratazzi, Zhiqiang Wu
Signal Classification In Fading Channels Using Cyclic Spectral Analysis, Eric Like, Vasu D. Chakravarthy, Paul Ratazzi, Zhiqiang Wu
Electrical Engineering Faculty Publications
Cognitive Radio (CR), a hierarchical Dynamic Spectrum Access (DSA) model, has been considered as a strong candidate for future communication systems improving spectrum efficiency utilizing unused spectrum of opportunity. However, to ensure the effectiveness of dynamic spectrum access, accurate signal classification in fading channels at low signal to noise ratio is essential. In this paper, a hierarchical cyclostationary-based classifier is proposed to reliably identify the signal type of a wide range of unknown signals. The proposed system assumes no a priori knowledge of critical signal statistics such as carrier frequency, carrier phase, or symbol rate. The system is designed with …
Least-Squares Approximate Solution Of Overdetermined Sylvester Equations, A. Scottedward Hodel, Pradeep Misra
Least-Squares Approximate Solution Of Overdetermined Sylvester Equations, A. Scottedward Hodel, Pradeep Misra
Electrical Engineering Faculty Publications
We address the problem of computing a low-rank estimate Y of the solution X of the Lyapunov equation AX + XA' + Q = O without computing the matrix X itself. This problem has applications in both the reduced-order modeling and the control of large dimensional systems as well as in a hybrid algorithm for the rapid numerical solution of the Lyapunov equation via the alternating direction implicit method. While no known methods for low-rank approximate solution provide the two-norm optimal rank k estimate Xk of the exact solution X of the Lyapunov equation, our iterative algorithms provide an effective …
Computation Of Stable Invariant Subspaces Of Hamiltonian Matrices, R. V. Patel, Z. Lin, Pradeep Misra
Computation Of Stable Invariant Subspaces Of Hamiltonian Matrices, R. V. Patel, Z. Lin, Pradeep Misra
Electrical Engineering Faculty Publications
This paper addresses some numerical issues that arise in computing a basis for the stable invariant subspace of a Hamiltonian matrix. Such a basis is required in solving the algebraic Riccati equation using the well-known method due to Laub. Two algorithms based on certain properties of Hamiltonian matrices are proposed as viable alternatives to the conventional approach.
Finite-Dimensional Approximations Of Unstable Infinite-Dimensional Systems, G. Gu, P. P. Khargonekar, E. B. Lee, Pradeep Misra
Finite-Dimensional Approximations Of Unstable Infinite-Dimensional Systems, G. Gu, P. P. Khargonekar, E. B. Lee, Pradeep Misra
Electrical Engineering Faculty Publications
This paper studies approximation of possibly unstable linear time-invariant infinite-dimensional systems. The system transfer function is assumed to be continuous on the imaginary axis with finitely many poles in the open right half plane. A unified approach is proposed for rational approximations of such infinite-dimensional systems. A procedure is developed for constructing a sequence of finite-dimensional approximants, which converges to the given model in the L infinity norm under a mild frequency domain condition. It is noted that the proposed technique uses only the FFT and singular value decomposition algorithms for obtaining the approximations. Numerical examples are included to illustrate …