Browsing by Keywords "Approximation theory"
Now showing items 120 of 64

Accurate method for obtaining band gaps in conducting polymers using a DFT/hybrid approach
(American Chemical Society, 1998)DFT calculations on a series of oligomers have been used to estimate band gaps, ionization potentials, electron affinities, and bandwidths for polyacetylene, polythiophene, polypyrrole, polythiazole, and a thiophene  ... 
Adaptive control design for nonlinear systems via successive approximations
(American Society of Mechanical Engineers, 2017)The paper presents an approach to the Model Reference Adaptive Control (MRAC) design for nonlinear dynamical systems. A nonlinear reference system is considered such that its response is designed to be stable via Successive ... 
Animation of deformable models
(Pergamon Press, 1994)Although kinematic modelling methods are adequate for describing the shapes of static objects, they are insufficient when it comes to producing realistic animation. Physically based modelling remedies this problem by ... 
An approximate analytical method of analysis of a threshold maintenance policy for a multiphase multicomponent model
(Springer, 2003)A multicomponent system is investigated that consists of n identical unreliable components whose nonfailure operating time consists of a number of sequential phases with exponential times. A maintenance policy is studied ... 
Approximations in compensator design: a duality
(The Institution of Engineering and Technology (IET), 2002)In classical controller design, poles fat to the left of dominant poles are sometimes ignored. Similarly, in some proportionalintegral compensation techniques, the controller zero is placed close to the origin and design ... 
Automatic multimedia crossmodal correlation discovery
(2004)Given an image (or video clip, or audio song), how do we automatically assign keywords to it? The general problem is to find correlations across the media in a collection of multimedia objects like video clips, with colors, ... 
Block SOR for Kronecker structured representations
(Elsevier, 2004)The Kronecker structure of a hierarchical Markovian model (HMM) induces nested block partitionings in the transition matrix of its underlying Markov chain. This paper shows how sparse real Schur factors of certain diagonal ... 
Capacity bounds for an ultrawideband channel model
(2004)There is an ongoing effort by the IEEE 802.15.3a subcommittee to reach a UWB personal area network standard. We estimate the achievable rates for such networks using a channel model specified by the same group. The analysis ... 
Collective modes in a quasionedimensional, twocomponent electron liquid
(Pergamon Press, 1994)Under favorable conditions, a new collective mode besides the usual plasmons may exist in degenerate electronhole liquids. We calculate the dispersion and damping of this new mode (called the acoustic plasmon mode) in a ... 
Collective modes in flux line liquids
(IOP, 2000)We study the collective modes of flux line liquids such as occur in the typeII superconductors of recent interest composed of twodimensional layered structures. Starting from the vortexvortex interaction and employing ... 
Computation of holographic patterns between tilted planes
(S P I E  International Society for Optical Engineering, 2006)Computation of the diffraction pattern that gives the desired reconstruction of an object upon proper illumination is an important process in computer generated holography. A fast computational method, based on the plane ... 
Computationally efficient wavelet affine invariant functions for shape recognition
(IEEE, 2004)An affine invariant function for object recognition is constructed from wavelet coefficients of the object boundary. In previous works, undecimated dyadic wavelet transform was used to construct affine invariant functions. ... 
Confined optical phonon effects on the band gap renormalization in quantum wire structures
(Elsevier Science, 1999)We consider the different approximations for the bandgap renormalization (BGR) within the random phase approximation (RPA), the quasistatic limit and the plasmonpole approximation, and compare with the full result. We ... 
Correlation effects in a onedimensional electron gas with shortrange interaction
(Pergamon Press, 1999)We study the correlation effects in a onedimensional electron gas with repulsive deltafunction interaction. The correlation effects are described by a localfield correction which takes into account the shortrange ... 
Costefficient approximation of linear systems with repeated and multichannel filtering configurations
(IEEE, Piscataway, NJ, United States, 1998)It is possible to obtain either exact realizations or useful approximations of linear systems or matrixvector products arising in many different applications, by synthesizing them in the form of repeated or multichannel ... 
Coulomb drag effect in parallel cylindrical quantum wires
(Pergamon Press, 1996)We study the Coulomb drag rate for electrons in two parallel quantum wires. The doublequantum wire structure is modeled for a GaAs material with cylindrical wires having infinite potential barriers. The momentum transfer ... 
Coupled optical microcavities in onedimensional photonic bandgap structures
(Institute of Physics Publishing, 2001)We present a detailed theoretical and experimental study of the evanescent coupled optical microcavity modes in onedimensional photonic bandgap structures. The coupledcavity samples are fabricated by depositing alternating ... 
Digital computation of the fractional Fourier transform
(Institute of Electrical and Electronics Engineers, 199609)An algorithm for efficient and accurate computation of the fractional Fourier transform is given. For signals with timebandwidth product N, the presented algorithm computes the fractional transform in O(NlogN) time. A ... 
Dynamical screening effects in hotelectron scattering from electronhole plasma and LOphonon modes in quantum wires
(Elsevier, 1996)We present a fully dynamical and finite temperature study of the hotelectron momentum relaxation rate and the power loss in a coupled system of electronhole plasma and bulk LOphonons in a quantum wire structure. ... 
Effect of crosssectional geometry on the RPA plasmons of quantum wires
(Pergamon Press, 1994)The effect of crosssectional geometry on both the intrasubband plasmon and intersubband plasmon of a quantum wire is investigated within a twosubband RPA scheme. Exact analytical electronic wavefunctions for circular, ...