نتایج جستجو برای: dft

تعداد نتایج: 19542  

2009
Aliaksei Sandryhaila Amina Chebira Markus Püschel Jelena Kovačević

We propose a design procedure for the real, equal-norm, lapped tight frame transforms (LTFTs). These transforms have been recently proposed as both a redundant counterpart to lapped orthogonal transforms and an infinite-dimensional counterpart to harmonic tight frames. In addition, LTFTs can be efficiently implemented with filter banks. The procedure consists of two steps. First, we construct n...

Journal: :Signal Processing 2011
Ahmet Serbes Lutfiye Durak-Ata

We introduce a new discrete fractional Fourier transform (DFrFT) based on only the DFT matrix and its powers. Eigenvectors of the DFT matrix are obtained in a simple-yetelegant and straightforward manner. We show that this DFrFT definition based on the eigentransforms of the DFT matrix mimics the properties of continuous fractional Fourier transform (FrFT) by approximating the samples of the co...

2013
GREG W. ANDERSON

A fundamental result of free probability theory due to Voiculescu and subsequently refined by many authors states that conjugation by independent Haar-distributed random unitary matrices delivers asymptotic freeness. In this paper we exhibit many other systems of random unitary matrices that, when used for conjugation, lead to freeness. We do so by first proving a general result asserting “asym...

Journal: :international journal of high risk behaviors and addiction 0
touran shahraki department of pediatrics, faculty of medicine, zahedan university of medical sciences, zahedan, ir iran; children and adolescent health research center, zahedan university of medical sciences, zahedan, ir iran mansour shahraki children and adolescent health research center, zahedan university of medical sciences, zahedan, ir iran; department of nutrition, faculty of medicine, zahedan university of medical sciences, zahedan, ir iran; department of pediatrics and children and adolescent health research center, zahedan university of medical sciences, zahedan, ir iran. tel: +98-9155421310, fax: +98-541 3425728 salehe omrani mehr zahedan university of medical sciences, zahedan, ir iran

background: a balanced nutrition schedule provides the essential substances for proper oral health. objectives: the aim of this study was to investigate the association between dental caries and body mass index in 6-11 year-old children in zahedan. materials and methods: in this cross-sectional study 1213 children (670 girls, 543 boys) were included. body mass index (bmi) and clinical examinati...

ژورنال: :پژوهش فیزیک ایران 0
الهام خراسانی e khorasani department of physics, isfahan university of technology, isfahan, iranدانشکده فیزیک، دانشگاه صنعتی اصفهان نجمه دیلی نظر n deylinazar department of physics, isfahan university of technology, isfahan, iranدانشکده فیزیک، دانشگاه صنعتی اصفهان مجتبی اعلایی m alaei, department of physics, isfahan university of technology, isfahan, iranدانشکده فیزیک، دانشگاه صنعتی اصفهان فرهاد شهبازی f shahbazi department of physics, isfahan university of technology, isfahan, iranدانشکده فیزیک، دانشگاه صنعتی اصفهان

پدیده ناکامی هندسی در اکسیدهای پایروکلر مغناطیسی موجب بروز خواص جالب در این مواد در دماهای پایین می شود. از این رو دو ماده چالش بر انگیز، و را از اکسیدهای پایروکلر انتخاب کردیم و این دو ماده را با استفاده از روش ابتدا به ساکن بر پایه نظریه تابعی چگالی مورد بررسی قرار دادیم. برای اعمال صحیح برهم کنش های کولمبی الکترون های f، رهیافت dft+u را با استفاده از روش تصحیح هابارد را به کار گرفتیم. در این...

Journal: :Ukrainian Journal of Physics 2022

???????i? ??i??i??????? ?? ??i???i????? ???? ???i?? ? ?????????? ???? ????i????? ???????? ?????i?????? ???????????i? ???????? ?i?i????? ???????????. ??????i?? i???????????? ?i?????? ??? ?????i ?????????i????? ?????????? (IEF-PCM) ?????????? ?????? ?????????? ???????????????? ?? ?i??i ????i? B3LYP/6-311++G(d,p). ??????i ??’???? ?i? ????????? ????????? ????i? ? ????????? (AIM) i ????????????? ???...

2003
Eftychios V. Papoulis Tania Stathaki

A DFT algorithm, the Extended Subband DFT (ESB−−DFT), is presented, which aims to overcome the problem of low accuracy the Subband DFT (SB−−DFT) algorithm suffers from, when applied in its approximate mode for signals with full spectrum. The proposed ESB−DFT is based upon the analysis of the input signal using a Filter Bank (FB) and the computation of its DFT from the lower length DFTs that cor...

Journal: :journal of dental research, dental clinics, dental prospects 0
mostafa sadeghi farnosh alizadeh

background and aims. childhood obesity has been associated with high refined sugar intake. the relationship between sucrose intake and development of dental caries has been established. the aim of this study was to determine the association between age-specific body mass index (bmi-for-age) and dental caries in children. materials and methods. in this cross-sectional study a total of 1003 child...

Journal: :Journal of chemical theory and computation 2014
Kurt R Brorsen Federico Zahariev Hiroya Nakata Dmitri G Fedorov Mark S Gordon

The equations for the response terms for the fragment molecular orbital (FMO) method interfaced with the density functional theory (DFT) gradient are derived and implemented. Compared to the previous FMO-DFT gradient, which lacks response terms, the FMO-DFT analytic gradient has improved accuracy for a variety of functionals, when compared to numerical gradients. The FMO-DFT gradient agrees wit...

Journal: :The Journal of chemical physics 2012
Sebastian Höfener André Severo Pereira Gomes Lucas Visscher

In this article, we present a consistent derivation of a density functional theory (DFT) based embedding method which encompasses wave-function theory-in-DFT (WFT-in-DFT) and the DFT-based subsystem formulation of response theory (DFT-in-DFT) by Neugebauer [J. Neugebauer, J. Chem. Phys. 131, 084104 (2009)] as special cases. This formulation, which is based on the time-averaged quasi-energy form...

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