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International Conference on BioMedical engineering and Informatics (BMEI)

作者： Chong Chen Guoliang Xu Institute of Computational Mathematics and Scientific Engineering Computing State Key Laboratory of Scientific and Engineering Computing Chinese Academy of Sciences Beijing China Institute of Computational Mathematics and Scientific Engineering Computing State Key Laboratory of Scientific and Engineering Computing Chinese Academy and Sciences Beijing China

We present a new optimization-based reconstruction model with geometric feature-preserving regularization. The previous construction approach of optimization-based requires generally solving a tremendously large discrete linear system. In addition, the analytic algorithms, such as, back-projection related methods, Fourier transform based reconstruction algorithms, are sensitive to noise. These disadvantages motivate us naturally to present a new optimization-based regularization algorithm, as distinct from traditionally constructing a discrete linear system, that is based upon a continuous energy functional model like analytic one. Some theoretical derivations and numerical computing of our model are discussed. Experimental results illustrate the desirable performance of the algorithm under various noiseless data situations. And the geometric feature-preserving regularizer is used in numerical simulations to demonstrate the robustness and effectiveness of the algorithm under various contaminated data scenarios.

关键词： Image reconstruction Noise Distributed databases Mathematical model computational modeling Numerical models Computed tomography

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Half-life of the Iπ = 4− Intruder State in 34P Using LaBr3:Ce Fast Timing

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Journal of Physics: Conference Series 2012年第1期381卷

作者： P J R Mason T Alharbi P H Regan N Mǎrginean Zs Podolyàk N Alkhomashi P C Bender M Bowry M Bostan D Bucurescu A M Bruce G Cǎta-Danil I Cǎta-Danil R Chakrabarti D Deleanu P Detistov M N Erduran D Filipescu U Garg T Glodariu D Ghiţǎ S S Ghugre A Kusoglu R Mǎrginean C Mihai M Nakhostin A Negret S Pascu C Rodríguez Triguero T Sava E C Simpson A K Sinha L Stroe G Suliman N V Zamfir Department of Physics University of Surrey Guildford Surrey GU2 7XH UK Department of Physics Almajmaah University PO Box 66 11952 Saudi Arabia Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH) R-76900 Bucharest Romania KACST P.O Box 6086 Riyadh 11442 Saudi Arabia Department of Physics Florida State University Tallahassee Florida USA Department of Physics Istanbul University 34134 Istanbul Turkey School of Computing Engineering and Mathematics University of Brighton Brighton BN2 4GJ UK UGC-DAE Consortium for Scientific Research Kolkata Centre Kolkata 700098 India Institute for Nuclear Research and Nuclear Energy (INRNE) Bulgarian Academy of Sciences Sofia Bulgaria Department of Computer Engineering Istanbul Sabahattin Zaim University Istanbul Turkey Department of Physics University of Notre Dame Notre Dame Indiana 46556 USA

The half-life of the Iπ = 4− intruder state at 2305 keV in 3415P19 has been measured using γ-ray coincident fast timing with LaBr3:Ce scintillation detectors. Excited states in 34P were populated in the 18O(18O,pn)34P reaction at a beam energy of 36 MeV at the Tandem Laboratory at the National institute of Physics and Nuclear engineering, Bucharest, Romania. A half-life of t1/2 ~ 2 ns was obtained for the 4− state, giving an M2 reduced transition probability consistent with similar transitions in this mass region and confirming the intruder-parity nature of the state.

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Energy Spectra in Rayleigh-Benard Convection

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Journal of Physics: Conference Series 2011年第8期318卷

作者： Mahendra K Verma Pankaj Mishra Mani Chandra Supriyo Paul Department of Physics Indian Institute of Technology Kanpur India 208016 Computational Fluid Dynamics Team Scientific and Engineering Computation Group Centre for Development of Advanced Computing Pune India 411007

We present a numerical study of the energy spectra and fluxes in the inertial range of turbulent Rayleigh-Bénard convection for a wide range of Prandtl number. We consider both free-slip and no-slip conditions for our simulation. Our results support the Kolmogorov-Obukhov (KO) scaling for velocity field for zero-Prandtl number and low-Prandtl number (P 1) convection. For large Prandtl number (P > 1) convection, the Bolgiano-Obukhov scaling (BO) appears to agree with the numerical results better than the KO scaling. We provide phenomenological arguments for the zero-Prandtl and low-Prandtl number convection.

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A Multitier System for the Verification, Visualization and Management of CHIMERA

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Procedia Computer Science 2011年 4卷 2076-2085页

作者： E.J. Lingerfelt O.E.B. Messer J.A. Osborne R.D. Budiardja A. Mezzacappa Computer Science and Mathematics Division Oak Ridge National Laboratory Oak Ridge TN 37831-6354 Leadership Computing Facility Oak Ridge National Laboratory Oak Ridge TN 37831-6354 Department of Physics and Astronomy University of Tennessee Knoxville TN 37996-1200 Department of Electrical Engineering and Computer Science University of Tennessee Knoxville TN 37996-2100 NSF Teragrid XD RDAVCenter National Institute for Computational Sciences University of Tennessee Knoxville TN 37996-2100 Physics Division Oak Ridge National Laboratory Oak Ridge TN 37831-6354

CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. Given CHIMERA's complexity and pace of ongoing development, a new support system, Bellerophon, has been designed and implemented to perform automated verification, visualization and management tasks while integrating with other workflow systems utilized by CHIMERA's development group. In order to achieve these goals, a multitier approach has been adopted. By integrating supercomputing platforms, visualization clusters, a dedicated web server and a client-side desktop application, this system attempts to provide an encapsulated, end-to-end solution to these needs.

关键词： Supernovae Visualization Regression test Code verification Multitier system

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Flexible alignment of images using B-spline reparameterization and L2-gradient flows

Flexible alignment of images using B-spline reparameterizati...

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Congress on Image and Signal Processing, CISP

作者： Guoliang Xu Yanmei Zheng State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics Chinese Academy and Sciences Beijing China

In this paper, we present a new flexible alignment method to align two or more similar images. By minimizing an energy functional measuring the difference of the initial image and target image, a L 2 -gradient flow is derived. The flow is integrated by a finite element method in the spatial direction and a semi-implicit Euler scheme in the temporal direction. The experimental results show that the proposed method is efficient, effective and capable of capturing large variation of the initial and the target images.

关键词： Spline Image registration Linear systems Correlation Equations

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Wave propagation and boundary absorbing with the high order finite element method

Wave propagation and boundary absorbing with the high order ...

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第七届计算物理国际会议

作者： Wensheng Zhang Chaowei Wang State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing P.O.Box 2719 100190

Wave propagation simulation has important applications in oil ***, the finite difference method is the most popular numerical method for simulation of wave propa gation as it has high computational efficiency and is easy to handle boundary *** this paper, we focus on how to simulate wave propagation efficiently by high order Lagrange element on triangular *** the mass matrix must be inverted at each time step, the mass lumping technique is required to improve *** low order such as linear Lagrange element, the mass lumping can be implemented by using the quadratic rules for numerical integration, but it is not obvious for high order Lagrange finite element.

关键词： wave equation finite element mass lumping boundary absorbing

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RETRACTED ARTICLE: Application of improved genetic algorithm in microstructure optimization of closed-cell material

RETRACTED ARTICLE: Application of improved genetic algorithm...

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作者： Zhao, Junfeng Cui, Junzhi Li, Wei Department of Applied Mathematics Northwestern Polytechnical University Xi'an Shaanxi 710072 China Institute of Computational Mathematics and Science-Engineering Computing Chinese Academy of Sciences Beijing 10080 China Department of Mathematics School of Science Xidian University Xi'an Shaanxi 710071 China

ISBN: (纸本)9781424472369

In this paper, we proposed an improved niche genetic algorithm on the basis of the density clustering-based DBSCAN algorithm which can distinct between niches dynamically and maintain the ability of population diversity. Its application in the field of closed-cell material optimization shows that the algorithm can effectively overcome some shortcomings, such as prematurity, poor local search capabilities in simple genetic algorithms. Moreover, this algorithm can get the results with a higher precision in a short time. © 2010 IEEE.

关键词： Clustering algorithms

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Optimum design for microstructures of closed-cell materials based on thermal conductivity

Optimum design for microstructures of closed-cell materials ...

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2010 International Conference on computational and Information Sciences, ICCIS2010

ISBN: (纸本)9780769542706

Taking our proposition about the grid-based simulation for the microstructure of the closed-cell foam into account, and choosing position of voids as optimal variables, this paper builds an optimal model for the two-phase material with maximizing the effective thermal conductivity of the microstructure. Then the paper seeks its solution by using the genetic algorithm. The numerical results show that the optimal model we built is reasonable and the optimal algorithm we used to solve this model is also effective. Furthermore, the results illustrate how the related factors make an effect on the optimal solution. © 2010 IEEE.

关键词： Genetic algorithms

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Improved analysis of rectangular dielectric waveguides based on a legendre pseudospectral penalty scheme

Improved analysis of rectangular dielectric waveguides based...

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Integrated Photonics Research, Silicon and Nanophotonics, IPRSN 2010

作者： Chiang, Shun-Fan Lin, Bang-Yan Teng, Chun-Hao Chang, Hung-Chun Department of Electrical Engineering Graduate Institute of Photonics and Optoelectronics Graduate Institute of Communication Engineering National Taiwan University Taipei 10617 Taiwan Department of Applied Mathematics and Center of Mathematical Modeling and Scientific Computing National Chiao Tung University Hsinchu 30010 Taiwan

A Legendre pseudospectral method with penalty scheme is established in frequency domain for high-accuracy waveguide mode analysis. For a square dielectric waveguide, the calculated modal index is seen to converge to t... 详细信息

ISBN: (纸本)9781557528957

关键词： Frequency domain analysis

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Hybrid Distributed-/Shared-Memory Parallelization For Re-initializing Level Set Functions

Hybrid Distributed-/Shared-Memory Parallelization For Re-ini...

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IEEE International Conference on High Performance computing and Communications (HPCC)

作者： Oliver Fortmeier H. Martin Bucker Institute for Scientific Computing Center for Computational Engineering Science (CCES) RWTH Aachen University Aachen Germany

The ever-increasing power of high-performance computers and advances in numerical techniques make possible the realistic study of two-phase flow problems in three spatial dimensions. Unfortunately, today, there is often still a gap between the design of numerical algorithms and the characteristics of the hardware on which the algorithms are executed. For the solution of a particular sub problem of a two-phase flow problem, we develop a numerical algorithm that aims to match the architecture of a cluster of nodes with multi-core chips. The algorithm is concerned with the re-initialization of level set function used to keep track of the interface between two phases of a fluid. It consists of a hybrid MPI/OpenMP parallelization strategy, using a domain decomposition approach on the outermost level of parallelization. On the inner level, a parallel region handles an individual sub domain. So, a domain decomposition approach based on MPI is combined with an OpenMP approach leading to a hybrid distributed-/shared-memory parallelization. Numerical experiments show that using such a hybrid strategy scales better than a pure MPI parallelization on two different Xeon-based clusters of quad-core processors using up to 1024 cores.

关键词： Level set Nearest neighbor searches Parallel algorithms Mathematical model Program processors Equations

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