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Annual IEEE India Conference

作者： Chandrajit Pal Kunal N. Chaudhury Asit Samanta Amlan Chakrabarti Ranjan Ghosh A.K Choudhury School of Information Technology University of Calcutta Program in Applied and Computational Mathematics (PACM) Princeton University Institute of RadioPhysics and Electronics University of Calcutta

ISBN: (纸本)9781479922765

Bilateral filters are widely used in computer vision and digital imaging applications such as denoising, video abstraction, demosaicing, optical-flow estimation etc. to name a few. Its smoothing and edge preserving characteristics suites perfectly for image and video processing applications, yet its high computational complexity makes real-time hardware implementation a challenging task. This paper provides an efficient Field programmable Gate Array (FPGA) based implementation of an edge preserving fast bilateral filter on a hardware software co-design environment of a most recent algorithm preserving the boundaries, spikes and canyons in presence of noise. Further, the four stage parallel pipelined architecture greatly improves the speed of operation. Moreover, our separable kernel implementation of the filtering hardware increases the speed of execution by almost five times than the traditional convolution filtering, while utilizing less hardware resource.

关键词： Bilateral filter edge-preserving smoothing constant-time algorithm O(1) complexity raised cosines FPGA system generator VHDL

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Angular-Momentum-Dependent Orbital-Free Density Functional Theory

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Physical Review Letters 2013年第6期111卷 066402-066402页

作者： Youqi Ke Florian Libisch Junchao Xia Lin-Wang Wang Emily A. Carter Department of Mechanical and Aerospace Engineering Program in Applied and Computational Mathematics and Andlinger Center for Energy and the Environment Princeton University Princeton New Jersey 08544 USA Material Science Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA

Orbital-free (OF) density functional theory (DFT) directly solves for the electron density rather than the wave function of many electron systems, greatly simplifying and enabling large scale first principles simulations. However, the required approximate noninteracting kinetic energy density functionals and local electron-ion pseudopotentials severely restrict the general applicability of conventional OFDFT. Here, we present a new generation of OFDFT called angular-momentum-dependent (AMD)-OFDFT to harness the accuracy of Kohn-Sham DFT and the simplicity of OFDFT. The angular momenta of electrons are explicitly introduced within atom-centered spheres so that the important ionic core region can be accurately described. In addition to conventional OF total energy functionals, we introduce a crucial nonlocal energy term with a set of AMD energies to correct errors due to the kinetic energy density functional and the local pseudopotential. We find that our AMD-OFDFT formalism offers substantial improvements over conventional OFDFT, as we show for various properties of the transition metal titanium.

关键词： Angular momentum

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Erratum: “Effect of dimensionality on the continuum percolation of overlapping hyperspheres and hypercubes. II. Simulation results and analyses” [J. Chem. Phys. 137, 074106 (2012)]

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The Journal of Chemical Physics 2014年第15期141卷

作者： S. Torquato Y. Jiao 1Department of Chemistry Department of Physics Princeton Center for Theoretical Science and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA 2Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA

In Table I and the caption of Fig. 8 of Ref. 1, the numerical value of the percolation threshold ηc of three-dimensional overlapping spheres as determined via t

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Precise algorithm to generate random sequential addition of hard hyperspheres at saturation

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Physical Review E 2013年第5期88卷 053312-053312页

作者： G. Zhang S. Torquato Department of Chemistry Princeton University Princeton New Jersey 08544 USA. Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA.

The study of the packing of hard hyperspheres in d-dimensional Euclidean space Rd has been a topic of great interest in statistical mechanics and condensed matter theory. While the densest known packings are ordered in sufficiently low dimensions, it has been suggested that in sufficiently large dimensions, the densest packings might be disordered. The random sequential addition (RSA) time-dependent packing process, in which congruent hard hyperspheres are randomly and sequentially placed into a system without interparticle overlap, is a useful packing model to study disorder in high dimensions. Of particular interest is the infinite-time saturation limit in which the available space for another sphere tends to zero. However, the associated saturation density has been determined in all previous investigations by extrapolating the density results for nearly saturated configurations to the saturation limit, which necessarily introduces numerical uncertainties. We have refined an algorithm devised by us [S. Torquato, O. U. Uche, and F. H. Stillinger, Phys. Rev. E 74, 061308 (2006)] to generate RSA packings of identical hyperspheres. The improved algorithm produce such packings that are guaranteed to contain no available space in a large simulation box using finite computational time with heretofore unattained precision and across the widest range of dimensions (2≤d≤8). We have also calculated the packing and covering densities, pair correlation function g2(r), and structure factor S(k) of the saturated RSA configurations. As the space dimension increases, we find that pair correlations markedly diminish, consistent with a recently proposed “decorrelation” principle, and the degree of “hyperuniformity” (suppression of infinite-wavelength density fluctuations) increases. We have also calculated the void exclusion probability in order to compute the so-called quantizer error of the RSA packings, which is related to the second moment of inertia of the average Voronoi cell.

关键词： Computation theory

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Difficulty in predicting shallow defects with hybrid functionals: Implication of the long-range exchange interaction

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Physical Review B 2013年第3期88卷 035134-035134页

作者： Junhyeok Bang Y. Y. Sun Tesfaye A. Abtew Amit Samanta Peihong Zhang S. B. Zhang Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA Department of Physics University at Buffalo State University of New York Buffalo New York 14260 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08540 USA

We identify an important issue in defect studies using hybrid functionals. When modeling a defect, which is supposedly an isolated system, with a finite-size supercell, the inclusion of a fraction of the Hartree-Fock interaction results in a strong cell-size dependence and an extremely slow convergence of the calculated defect properties, especially for shallow defect. These behaviors may give rise to a number of errors in calculated defect properties, including the deepening of transition level and overstabilization of shallow defects. Numerical results from hybrid functional calculations for a diverse array of systems can be understood within the Hartree-Fock theory of an electron-gas model, indicating that the long-range exchange is the main cause for the errors in the calculated defect properties within hybrid functionals.

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AMUSE: Empowering Users for Cost-Aware Offloading with Throughput-Delay Tradeoffs

AMUSE: Empowering Users for Cost-Aware Offloading with Throu...

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IEEE INFOCOM Conference

作者： Youngbin Im Carlee Joe-Wong Sangtae Ha Soumya Sen Ted "Taekyoung" Kwon Mung Chiang School of Computer Science and Engineering Seoul National University Seoul Korea Program in Applied and Computational Mathematics Princeton University Princeton NJ USA Department of Electrical Engineering Princeton University Princeton NJ USA

ISBN: (纸本)9781467359443

Mobile users face a tradeoff between cost, through-put, and delay in making their offloading decisions. To navigate this tradeoff, we propose AMUSE (Adaptive bandwidth Management through USer-Empowerment), a practical, cost-aware WiFi offloading system that takes into account a user's throughput-delay tradeoffs and cellular budget constraint. Based on predicted future usage and WiFi availability, AMUSE decides which applications to offload to what times of the day. To practically enforce the assigned rate of each TCP application, we introduce a receiver-side TCP bandwidth control algorithm that adjusts the rate by controlling the TCP advertisement window from the user side. We implement AMUSE on Windows 7 tablets and evaluate its effectiveness with 3G and WiFi usage data obtained from a trial with 25 mobile users. Our results show that AMUSE improves user utility.

关键词： tradeoffs UNLOADING Wi-Fi third generation rate control

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Atomic and electronic structures of single-layer FeSe on SrTiO3(001): The role of oxygen deficiency

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Physical Review B 2013年第22期87卷 220503(R)-220503(R)页

作者： Junhyeok Bang Zhi Li Y. Y. Sun Amit Samanta Y. Y. Zhang Wenhao Zhang Lili Wang X. Chen Xucun Ma Q.-K. Xue S. B. Zhang Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA Institute of Physics The Chinese Academy of Sciences Beijing 100190 China Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA Department of Physics Tsinghua University Beijing 100084 China

Using first-principles calculation, we propose an interface structure for single triple-layer FeSe on the SrTiO3(001) surface, a high-Tc superconductor found recently. The key component of this structure is the oxygen deficiency on the top layer of the SrTiO3 substrate, as a result of Se etching used in preparing the high-Tc samples. The O vacancies strongly bind the FeSe triple layer to the substrate giving rise to a (2×1) reconstruction, as observed by scanning tunneling microscopy. The enhanced binding correlates to the significant increase of Tc observed in experiment. The O vacancies also serve as the source of electron doping, which modifies the Fermi surface of the first FeSe layer by filling the hole pocket near the center of the surface Brillouin zone, as suggested from angle-resolved photoemission spectroscopy measurement.

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Efficient linear programming algorithm to generate the densest lattice sphere packings

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Physical Review E 2013年第6期87卷 063303-063303页

作者： Étienne Marcotte Salvatore Torquato Department of Physics Princeton University Princeton New Jersey 08544 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA Princeton Institute of the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA

Finding the densest sphere packing in d-dimensional Euclidean space Rd is an outstanding fundamental problem with relevance in many fields, including the ground states of molecular systems, colloidal crystal structures, coding theory, discrete geometry, number theory, and biological systems. Numerically generating the densest sphere packings becomes very challenging in high dimensions due to an exponentially increasing number of possible sphere contacts and sphere configurations, even for the restricted problem of finding the densest lattice sphere packings. In this paper we apply the Torquato-Jiao packing algorithm, which is a method based on solving a sequence of linear programs, to robustly reproduce the densest known lattice sphere packings for dimensions 2 through 19. We show that the TJ algorithm is appreciably more efficient at solving these problems than previously published methods. Indeed, in some dimensions, the former procedure can be as much as three orders of magnitude faster at finding the optimal solutions than earlier ones. We also study the suboptimal local density-maxima solutions (inherent structures or “extreme” lattices) to gain insight about the nature of the topography of the “density” landscape.

关键词： Spheres

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Nearly hyperuniform network models of amorphous silicon

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Physical Review B 2013年第24期87卷 245204-245204页

作者： Miroslav Hejna Paul J. Steinhardt Salvatore Torquato Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Center for Theoretical Science Princeton University Princeton New Jersey 08544 USA Department of Chemistry Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

We introduce the concept of nearly hyperuniform network (NHN) structures as alternatives to the conventional continuous random network (CRN) models for amorphous tetrahedrally coordinated solids, such as amorphous silicon (a-Si). A hyperuniform solid has a structure factor S(k) that approaches zero as the wavenumber k→0. We define a NHN as an amorphous network whose structure factor S(k→0) is smaller than the liquid value at the melting temperature. Using a novel implementation of the Stillinger-Weber potential for the interatomic interactions, we show that the energy landscape for a spectrum of NHNs includes a sequence of local minima with an increasing degree of hyperuniformity [smaller S(k→0)] that is significantly below the frozen-liquid value and that correlates with other measurable features in S(k) at intermediate and large k and with the width of the electronic band gap.

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Author Correction: Study of 300,486 individuals identifies 148 independent genetic loci influencing general cognitive function

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Nature communications 2019年第1期10卷 2068页

作者： Gail Davies Max Lam Sarah E Harris Joey W Trampush Michelle Luciano W David Hill Saskia P Hagenaars Stuart J Ritchie Riccardo E Marioni Chloe Fawns-Ritchie David C M Liewald Judith A Okely Ari V Ahola-Olli Catriona L K Barnes Lars Bertram Joshua C Bis Katherine E Burdick Andrea Christoforou Pamela DeRosse Srdjan Djurovic Thomas Espeseth Stella Giakoumaki Sudheer Giddaluru Daniel E Gustavson Caroline Hayward Edith Hofer M Arfan Ikram Robert Karlsson Emma Knowles Jari Lahti Markus Leber Shuo Li Karen A Mather Ingrid Melle Derek Morris Christopher Oldmeadow Teemu Palviainen Antony Payton Raha Pazoki Katja Petrovic Chandra A Reynolds Muralidharan Sargurupremraj Markus Scholz Jennifer A Smith Albert V Smith Natalie Terzikhan Anbupalam Thalamuthu Stella Trompet Sven J van der Lee Erin B Ware B Gwen Windham Margaret J Wright Jingyun Yang Jin Yu David Ames Najaf Amin Philippe Amouyel Ole A Andreassen Nicola J Armstrong Amelia A Assareh John R Attia Deborah Attix Dimitrios Avramopoulos David A Bennett Anne C Böhmer Patricia A Boyle Henry Brodaty Harry Campbell Tyrone D Cannon Elizabeth T Cirulli Eliza Congdon Emily Drabant Conley Janie Corley Simon R Cox Anders M Dale Abbas Dehghan Danielle Dick Dwight Dickinson Johan G Eriksson Evangelos Evangelou Jessica D Faul Ian Ford Nelson A Freimer He Gao Ina Giegling Nathan A Gillespie Scott D Gordon Rebecca F Gottesman Michael E Griswold Vilmundur Gudnason Tamara B Harris Annette M Hartmann Alex Hatzimanolis Gerardo Heiss Elizabeth G Holliday Peter K Joshi Mika Kähönen Sharon L R Kardia Ida Karlsson Luca Kleineidam David S Knopman Nicole A Kochan Bettina Konte John B Kwok Stephanie Le Hellard Teresa Lee Terho Lehtimäki Shu-Chen Li Christina M Lill Tian Liu Marisa Koini Edythe London Will T Longstreth Oscar L Lopez Anu Loukola Tobias Luck Astri J Lundervold Anders Lundquist Leo-Pekka Lyytikäinen Nicholas G Martin Grant W Montgomery Alison D Murray Anna C Need Raymond Noordam Lars Nyberg William Ollier Goran Papenberg Alison Pattie Ozren Polasek Russell A Poldrack Bruce M Psaty Sim Centre for Cognitive Ageing and Cognitive Epidemiology Department of Psychology School of Philosophy Psychology and Language Sciences The University of Edinburgh Edinburgh EH8 9JZ UK. Institute of Mental Health Singapore 539747 Singapore. Medical Genetics Section Centre for Genomic & Experimental Medicine MRC Institute of Genetics & Molecular Medicine University of Edinburgh Western General Hospital Edinburgh EH4 2XU UK. BrainWorkup LLC Los Angeles 90033 CA USA. Department of Psychiatry and Behavioral Sciences Keck School of Medicine University of Southern California Los Angeles 90033 CA USA. Social Genetic and Developmental Psychiatry Centre Institute of Psychiatry Psychology & Neuroscience King's College London De Crespigny Park Denmark Hill London SE5 8AF UK. Research Centre of Applied and Preventive Cardiovascular Medicine University of Turku Turku 20520 Finland. Department of Internal Medicine Satakunta Central Hospital Pori 28100 Finland. Centre for Global Health Research Usher Institute of Population Health Sciences and Informatics University of Edinburgh Teviot Place Edinburgh EH8 9AG Scotland. Max Planck Institute for Molecular Genetics Berlin 14195 Germany. Cardiovascular Health Research Unit Department of Medicine University of Washington Seattle 98101 Washington USA. Department of Psychiatry Icahn School of Medicine at Mount Sinai New York 10029 NY USA. Mental Illness Research Education and Clinical Center (VISN 3) James J. Peters VA Medical Center Bronx 10468 NY USA. Department of Psychiatry Brigham and Women's Hospital Harvard Medical School Boston 02115 MA USA. NORMENT K.G. Jebsen Centre for Psychosis Research Department of Clinical Science University of Bergen Bergen 5021 Norway. Dr. Einar Martens Research Group for Biological Psychiatry Center for Medical Genetics and Molecular Medicine Haukeland University Hospital Bergen 5020 Norway. Center for Psychiatric Neuroscience Feinstein Institute for Medical Resea

Christina M. Lill, who contributed to analysis of data, was inadvertently omitted from the author list in the originally published version of this article. This has now been corrected in both the PDF and HTML versions...

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