Density Functional Theory (DFT) which is based on quantum mechanics theory has been broadly used to compute the energy and the structure of molecules and solids. However, the DFT method is limited when running calculations for a large system and only thousands of atoms can be solved. Alternatively, Molecular Dynamics (MD) simulation can be used to investigate the properties of the atomic system...

We present a new technique for estimating speed and slip of the induction motor. The method is based on the time-frequency analysis of the current supplying the motor. Interpolated DFT, computed in the sliding time window, is used for obtaining current spectrograms with high frequency resolution. The speed and the slip are estimated from the fluctuation of amplitude of the main current harmonic...

∗ This work was supported partially by the NSC 92-2422-H009-010 ABSTRACT A watermarking method for copyright protection of color images against rotation and scaling attacks is proposed. A watermark is embedded in an input image as coefficient-value peaks circularly and symmetrically distributed in a middle band of the discrete Fourier transform (DFT) domain of the input image. By detecting the ...

ABSTARCTDFT spreading is one of the techniques introduced for peak to average power ratio (PAPR) reduction of OFDM systems. In this technique, the input signal with DFT is spreaded such that the PAPR is minimized but this can reduce the PAPR of OFDM signal to the level of single carrier transmission. In this paper, a DFT spreading method is proposed for the PAPR reduction of OFDM systems with s...

The estimation of the frequency slope of a partial from its peak in the DFT spectrum today is possible only if a Gaussian window is used. In the following we derive a new method to estimate the frequency slope of a partial from its DFT spectral peak based on the reassignment operators. Compared to the Gaussian window based method our new method can be used with a much larger variety of windows ...

The performance of a variety of high-level composite procedures, as well as lower-cost density functional theory (DFT)- and second-order perturbation theory (MP2)-based methods, for the prediction of absolute and relative R-X bond dissociation energies (BDEs) was examined for R = Me, Et, i-Pr and t-Bu, and X = H, CH(3), OCH(3), OH and F. The methods considered include the high-level G3(MP2)-RAD...

Density functional theory (DFT) provides a formally exact framework for performing embedded subsystem electronic structure calculations, including DFT-in-DFT and wavefunction theory-in-DFT descriptions. In the interest of efficiency, it is desirable to truncate the atomic orbital basis set in which the subsystem calculation is performed, thus avoiding high-order scaling with respect to the size...

It has been shown that the underestimated by DFT/LDA(GGA) band-gap can be efficiently corrected by an averaging procedure of transition energies over a region close to the direct band-gap transition, which we call the ∆(EIG) method (the differences in the Kohn–Sham eigenvalues). For small excitations the averaging appears to be equivalent to the ∆(SCF) approach (differences in the self-consiste...

Due to the difficulty of test pattern generation for sequential circuits, several design-for-testability (DFT) approaches have been proposed. An improvement to these current approaches is needed to cater to the requirements of today’s more complicated chips. This paper introduces a new DFT method applicable to high-level description of circuits, which optimally utilizes existing functional elem...

O método DFTB, bem como a sua extensão com carga corrigida auto-consistente SCC-DFTB, tem ampliado a faixa de aplicações das ferramentas teóricas com fundamentos bem estabelecidos. Como uma aproximação do método do funcional de densidade, o método DFTB mantém aproximadamente a mesma precisão, mas com custo computacional menor, permitindo a investigação da estrutura eletrônica de sistemas grande...