The problem of phase stability calculation (and crystal structure prediction) is a fundamental problem in materials research and development, and it is typically addressed with highly accurate quantum mechanical computations on a large set of candidate structures, but has limited predictive power. To allow fast prediction of crystal structures, two concepts, usual suspect structure database and...

High-performance discrete Fourier transform (DFT) libraries are an important requirement for many computing platforms. Unfortunately, developing and optimizing these libraries for modern, complex platforms has become extraordinarily difficult. Tomake thingsworse, performance often does not port, thus requiring permanent re-optimizations. Overcoming this problem has been the goal of SPIRAL, a li...

As the channel frequency responses (CFRs) at virtual pilot subcarriers are assumed to be zero, estimated CFRs will have a leakage effect for discrete Fourier transform (DFT)-based estimation in OFDM systems. The odd and even related if number of maximum delay points is smaller than or equal half pilots (including pilots). According this correlation, we propose low-complexity least-squares (LS) ...

Two filtering algorithms for removal of DC offset and subsynchronous resonance terms in the current/voltage signals in a transmission line under fault condition are presented. One of the algorithms utilizes the samples of the signal over a time interval slightly greater than one cycle time of the fundamental component and is computationally less demanding than the existing Fourier filters. The ...

Chloride ions were found to potentially increase activity of cerussite surfaces. Dissolution experiments, zeta potential measurements, X-ray photoelectron spectroscopy (XPS) studies, and density functional theory (DFT) computation were conducted in this study. Dissolution experiments showed that the lead ion concentrations in the NaCl solution system were lower than those in the deionized water...

A novel methyl (Z)-2-(2-(2-oxonaphthalen-1(2H)-ylidene)hydrazineyl)benzoate isomer ligand has been prepared instead of (E)-methyl 2-((2-hydroxynaphthalen-1-yl)diazenyl)benzoate in very good yield. The tautomerization diazene to hydrazine was computed via DFT; the single proton S(6) process confirmed by XRD. Moreover, XRD-crystal measurements supported form as preferred kinetic isomer; structure...

The challenge in a database of evolving time series is to provide efficient algorithms and access methods for query processing, taking into consideration the fact that the database changes continuously as new data become available. Traditional access methods that continuously update the data are considered inappropriate, due to significant update costs. In this paper, we use the IDC-Index (Incr...

We develop a low-energy continuum model for phonons in twisted moir\'e bilayers, based on configuration-space approach. In this approach, interatomic force constants are obtained from density functional theory (DFT) calculations of untwisted bilayers with various in-plane shifts. This allows efficient computation phonon properties any small twist angle, while maintaining DFT-level accuracy. Bas...

We consider the minimization of hit error rate (BER) for OFDM systems with orthogonal precoders. For low S N Q we show that the conventional OFDM system is the optimal solution and the optimal precoder is the identity matrix. For high SNR, corresponding to a relatively practical range of BER, there are channel independent solutions for optimal precoders. One such solution is the DFT matrix and ...

We study the problem of finding unitary submatrices of the discrete Fourier transform matrix. This problem is related to a diverse set of questions on idempotents on ZN , tiling ZN , difference graphs and maximal cliques. Each of these is related to the problem of interpolating a discrete bandlimited signal using an orthogonal basis.