3,966 research outputs found

    HITES 2012: 'Horizons of Innovative Theories, Experiments, and Supercomputing in Nuclear Physics'

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    This volume contains the contributions of the speakers of an international conference in honor of Jerry Draayer's 70th birthday, entitled 'Horizons of Innovative Theories, Experiments and Supercomputing in Nuclear Physics'. The list of contributors includes not only international experts in these fields, but also many former collaborators, former graduate students, and former postdoctoral fellows of Jerry Draayer, stressing innovative theories such as special symmetries and supercomputing, both of particular interest to Jerry. The organizers of the conference intended to honor Jerry Draayer not only for his seminal contributions in these fields, but also for his administrative skills at departmental, university, national and international level. Signed: Ted Hecht University of Michigan ##IMG## [http://ej.iop.org/images/1742-6596/403/1/011001/confphoto.jpg] {Conference photograph ----- -- Scientific Advisory Committee ----- -- Ani Aprahamian -- University of Notre Dame ----- -- Baha Balantekin -- University of Wisconsin ----- -- Bruce Barrett -- University of Arizona ----- -- Umit Catalyurek -- Ohio State Unversity ----- -- David Dean -- Oak Ridge National Laboratory ----- -- Jutta Escher (Chair) -- Lawrence Livermore National Laboratory ----- -- Jorge Hirsch -- UNAM, Mexico ----- -- David Rowe -- University of Toronto ----- -- Brad Sherill & Michigan State University ----- -- Joel Tohline -- Louisiana State University ----- -- Edward Zganjar -- Lousiana State University ----- -- Organizing Committee ----- -- Jeff Blackmon -- Louisiana State University ----- -- Mark Caprio -- University of Notre Dame ----- -- Tomas Dytrych -- Louisiana State University ----- -- Ana Georgieva -- INRNE, Bulgaria ----- -- Kristina Launey (Co-chair) -- Louisiana State University ----- -- Gabriella Popa -- Ohio University Zanesville ----- -- James Vary (Co-chair) -- Iowa State University ----- -- Local Organizing Committee ----- -- Laura Linhardt -- Louisiana State University ----- -- Charlie Rasco -- Louisiana State University ----- -- Karen Richard (Coordinator) -- Louisiana State University -----Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98638/1/1742-6596_403_1_011001.pd

    Preserving Command Line Workflow for a Package Management System Using ASCII DAG Visualization

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    Package managers provide ease of access to applications by removing the time-consuming and sometimes completely prohibitive barrier of successfully building, installing, and maintaining the software for a system. A package dependency contains dependencies between all packages required to build and run the target software. Package management system developers, package maintainers, and users may consult the dependency graph when a simple listing is insufficient for their analyses. However, users working in a remote command line environment must disrupt their workflow to visualize dependency graphs in graphical programs, possibly needing to move files between devices or incur forwarding lag. Such is the case for users of Spack, an open source package management system originally developed to ease the complex builds required by supercomputing environments. To preserve the command line workflow of Spack, we develop an interactive ASCII visualization for its dependency graphs. Through interviews with Spack maintainers, we identify user goals and corresponding visual tasks for dependency graphs. We evaluate the use of our visualization through a command line-centered study, comparing it to the system's two existing approaches. We observe that despite the limitations of the ASCII representation, our visualization is preferred by participants when approached from a command line interface workflow.U.S. Department of Energy by Lawrence Livermore National Laboratory [DE-AC52-07NA27344, LLNL-JRNL-746358]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    MILC Code Performance on High End CPU and GPU Supercomputer Clusters

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    With recent developments in parallel supercomputing architecture, many core, multi-core, and GPU processors are now commonplace, resulting in more levels of parallelism, memory hierarchy, and programming complexity. It has been necessary to adapt the MILC code to these new processors starting with NVIDIA GPUs, and more recently, the Intel Xeon Phi processors. We report on our efforts to port and optimize our code for the Intel Knights Landing architecture. We consider performance of the MILC code with MPI and OpenMP, and optimizations with QOPQDP and QPhiX. For the latter approach, we concentrate on the staggered conjugate gradient and gauge force. We also consider performance on recent NVIDIA GPUs using the QUDA library

    Equation of state of superfluid neutron matter and the calculation of 1S0^1S_0 pairing gap

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    We present a Quantum Monte Carlo study of the zero temperature equation of state of neutron matter and the computation of the 1S0^1S_0 pairing gap in the low-density regime with ρ<0.04\rho<0.04 fm3^{-3}. The system is described by a non-relativistic nuclear Hamiltonian including both two-- and three--nucleon interactions of the Argonne and Urbana type. This model interaction provides very accurate results in the calculation of the binding energy of light nuclei. A suppression of the gap with respect to the pure BCS theory is found, but sensibly weaker than in other works that attempt to include polarization effects in an approximate way

    Strain Modulated Electronic Properties of Ge Nanowires - A First Principles Study

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    We used density-functional theory based first principles simulations to study the effects of uniaxial strain and quantum confinement on the electronic properties of germanium nanowires along the [110] direction, such as the energy gap and the effective masses of the electron and hole. The diameters of the nanowires being studied are up to 50 {\AA}. As shown in our calculations, the Ge [110] nanowires possess a direct band gap, in contrast to the nature of an indirect band gap in bulk. We discovered that the band gap and the effective masses of charge carries can be modulated by applying uniaxial strain to the nanowires. These strain modulations are size-dependent. For a smaller wire (~ 12 {\AA}), the band gap is almost a linear function of strain; compressive strain increases the gap while tensile strain reduces the gap. For a larger wire (20 {\AA} - 50 {\AA}), the variation of the band gap with respect to strain shows nearly parabolic behavior: compressive strain beyond -1% also reduces the gap. In addition, our studies showed that strain affects effective masses of the electron and hole very differently. The effective mass of the hole increases with a tensile strain while the effective mass of the electron increases with a compressive strain. Our results suggested both strain and size can be used to tune the band structures of nanowires, which may help in design of future nano-electronic devices. We also discussed our results by applying the tight-binding model.Comment: 1 table, 8 figure
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