@article{13528, author = {{George, B. M. and Behrends, J. and Schnegg, A. and Schulze, T. F. and Fehr, M. and Korte, L. and Rech, B. and Lips, K. and Rohrmüller, M. and Rauls, E. and Schmidt, Wolf Gero and Gerstmann, Uwe}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{13}}, title = {{{Atomic Structure of Interface States in Silicon Heterojunction Solar Cells}}}, doi = {{10.1103/physrevlett.110.136803}}, volume = {{110}}, year = {{2013}}, } @article{13527, author = {{Rohrmüller, M. and Herres-Pawlis, S. and Witte, M. and Schmidt, Wolf Gero}}, issn = {{0192-8651}}, journal = {{Journal of Computational Chemistry}}, pages = {{1035--1045}}, title = {{{Bis-μ-oxo and μ-η2:η2-peroxo dicopper complexes studied within (time-dependent) density-functional and many-body perturbation theory}}}, doi = {{10.1002/jcc.23230}}, volume = {{34}}, year = {{2013}}, } @article{13525, abstract = {{The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the GW approximation to account for quasiparticle effects and the solution of the Bethe-Salpeter equation for the stoichiometric material yield a dielectric function that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are, at least, partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that the inclusion of self-energy effects in the nonlinear optical response leads to a better agreement with experiments. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular, for the 21 and 31 tensor components, further improving the agreement between experiments and theory.}}, author = {{Riefer, Arthur and Sanna, Simone and Schindlmayr, Arno and Schmidt, Wolf Gero}}, issn = {{1550-235X}}, journal = {{Physical Review B}}, number = {{19}}, publisher = {{American Physical Society}}, title = {{{Optical response of stoichiometric and congruent lithium niobate from first-principles calculations}}}, doi = {{10.1103/PhysRevB.87.195208}}, volume = {{87}}, year = {{2013}}, } @article{15867, author = {{Tautz, Raphael and Da Como, Enrico and Wiebeler, Christian and Soavi, Giancarlo and Dumsch, Ines and Fröhlich, Nils and Grancini, Giulia and Allard, Sybille and Scherf, Ullrich and Cerullo, Giulio and Schumacher, Stefan and Feldmann, Jochen}}, issn = {{0002-7863}}, journal = {{Journal of the American Chemical Society}}, pages = {{4282--4290}}, title = {{{Charge Photogeneration in Donor–Acceptor Conjugated Materials: Influence of Excess Excitation Energy and Chain Length}}}, doi = {{10.1021/ja309252a}}, year = {{2013}}, } @article{15866, author = {{Ardizzone, Vincenzo and Lewandowski, Przemyslaw and Luk, M. H. and Tse, Y. C. and Kwong, N. H. and Lücke, Andreas and Abbarchi, Marco and Baudin, Emmanuel and Galopin, Elisabeth and Bloch, Jacqueline and Lemaitre, Aristide and Leung, P. T. and Roussignol, Philippe and Binder, Rolf and Tignon, Jerome and Schumacher, Stefan}}, issn = {{2045-2322}}, journal = {{Scientific Reports}}, title = {{{Formation and control of Turing patterns in a coherent quantum fluid}}}, doi = {{10.1038/srep03016}}, year = {{2013}}, } @article{15868, author = {{Luk, M. H. and Tse, Y. C. and Kwong, N. H. and Leung, P. T. and Lewandowski, Przemyslaw and Binder, R. and Schumacher, Stefan}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, title = {{{Transverse optical instability patterns in semiconductor microcavities: Polariton scattering and low-intensity all-optical switching}}}, doi = {{10.1103/physrevb.87.205307}}, year = {{2013}}, } @article{15871, abstract = {{We derive a transparent and easy-to-use analytic expression for the selection rules and the optical dipole matrix elements for carbon nanotubes of arbitrary chirality in the presence of axial magnetic fields using a single-orbital π-electron tight-binding model. From this, we calculate the linear absorption spectrum for arbitrary polarization directions of the incident light, providing insight into all optically allowed transition. We show that the transverse absorption peaks can be selectively excited with circularly polarized light and spectrally resolved in an axial magnetic field.}}, author = {{Liu, Hong and Schumacher, Stefan and Meier, Torsten}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{3}}, title = {{{Selection rules and linear absorption spectra of carbon nanotubes in axial magnetic fields}}}, doi = {{10.1103/physrevb.88.035429}}, volume = {{88}}, year = {{2013}}, } @article{15870, author = {{Ling, Sanliang and Schumacher, Stefan and Galbraith, Ian and Paterson, Martin J.}}, issn = {{1932-7447}}, journal = {{The Journal of Physical Chemistry C}}, pages = {{6889--6895}}, title = {{{Excited-State Absorption of Conjugated Polymers in the Near-Infrared and Visible: A Computational Study of Oligofluorenes}}}, doi = {{10.1021/jp401359a}}, year = {{2013}}, } @article{13819, author = {{Riefer, A. and Sanna, S. and Schmidt, Wolf Gero}}, issn = {{0015-0193}}, journal = {{Ferroelectrics}}, pages = {{78--85}}, title = {{{LiNb1-xTaxO3Electronic Structure and Optical Response fromFirst-PrinciplesCalculations}}}, doi = {{10.1080/00150193.2013.821904}}, volume = {{447}}, year = {{2013}}, } @inbook{18475, abstract = {{The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the GW approximation to account for quasiparticle effects and the solution of the Bethe–Salpeter equation yield a dielectric function for the stoichiometric material that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are at least partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that self-energy effects improve the agreement between experiment and theory. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular for the 21 and 31 tensor components, further improving the agreement with measured data.}}, author = {{Riefer, Arthur and Rohrmüller, Martin and Landmann, Marc and Sanna, Simone and Rauls, Eva and Vollmers, Nora Jenny and Hölscher, Rebecca and Witte, Matthias and Li, Yanlu and Gerstmann, Uwe and Schindlmayr, Arno and Schmidt, Wolf Gero}}, booktitle = {{High Performance Computing in Science and Engineering ‘13}}, editor = {{Nagel, Wolfgang E. and Kröner, Dietmar H. and Resch, Michael M.}}, isbn = {{978-3-319-02164-5}}, pages = {{93--104}}, publisher = {{Springer}}, title = {{{Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations}}}, doi = {{10.1007/978-3-319-02165-2_8}}, year = {{2013}}, } @article{1965, abstract = {{Virtualization technology makes data centers more dynamic and easier to administrate. Today, cloud providers offer customers access to complex applications running on virtualized hardware. Nevertheless, big virtualized data centers become stochastic environments and the simplification on the user side leads to many challenges for the provider. He has to find cost-efficient configurations and has to deal with dynamic environments to ensure service level objectives (SLOs). We introduce a software solution that reduces the degree of human intervention to manage clouds. It is designed as a multi-agent system (MAS) and placed on top of the Infrastructure as a Service (IaaS) layer. Worker agents allocate resources, configure applications, check the feasibility of requests, and generate cost estimates. They are equipped with application specific knowledge allowing it to estimate the type and number of necessary resources. During runtime, a worker agent monitors the job and adapts its resources to ensure the specified quality of service—even in noisy clouds where the job instances are influenced by other jobs. They interact with a scheduler agent, which takes care of limited resources and does a cost-aware scheduling by assigning jobs to times with low costs. The whole architecture is self-optimizing and able to use public or private clouds. Building a private cloud needs to face the challenge to find a mapping of virtual machines (VMs) to hosts. We present a rule-based mapping algorithm for VMs. It offers an interface where policies can be defined and combined in a generic way. The algorithm performs the initial mapping at request time as well as a remapping during runtime. It deals with policy and infrastructure changes. An energy-aware scheduler and the availability of cheap resources provided by a spot market are analyzed. We evaluated our approach by building up an SaaS stack, which assigns resources in consideration of an energy function and that ensures SLOs of two different applications, a brokerage system and a high-performance computing software. Experiments were done on a real cloud system and by simulations.}}, author = {{Niehörster, Oliver and Simon, Jens and Brinkmann, André and Keller, Axel and Krüger, Jens}}, journal = {{Journal of Grid Computing}}, number = {{3}}, pages = {{553--577}}, title = {{{Cost-aware and SLO Fulfilling Software as a Service}}}, doi = {{10.1007/s10723-012-9230-7}}, volume = {{10}}, year = {{2012}}, } @inproceedings{2097, author = {{Kasap, Server and Redif, Soydan}}, booktitle = {{Proc. Int. Conf. on Field Programmable Technology (ICFPT)}}, pages = {{135--140}}, publisher = {{IEEE Computer Society}}, title = {{{FPGA-based design and implementation of an approximate polynomial matrix EVD algorithm}}}, doi = {{10.1109/FPT.2012.6412125}}, year = {{2012}}, } @inproceedings{2098, author = {{Kaiser, Jürgen and Meister, Dirk and Hartung, Tim and Brinkmann, André}}, booktitle = {{Proc. IEEE Int. Conf. on Parallel and Distributed Systems (ICPADS)}}, pages = {{181--188}}, publisher = {{IEEE}}, title = {{{ESB: Ext2 Split Block Device}}}, doi = {{10.1109/ICPADS.2012.34}}, year = {{2012}}, } @inproceedings{2099, author = {{Meister, Dirk and Kaiser, Jürgen and Brinkmann, André and Kuhn, Michael and Kunkel, Julian and Cortes, Toni}}, booktitle = {{Proc. Int. Conf. on Supercomputing (SC)}}, pages = {{7:1--7:11}}, publisher = {{IEEE Computer Society}}, title = {{{A Study on Data Deduplication in HPC Storage Systems}}}, doi = {{10.1109/SC.2012.14}}, year = {{2012}}, } @inproceedings{2100, author = {{Kasap, Server and Redif, Soydan}}, booktitle = {{Int. Architecture and Engineering Symp. (ARCHENG)}}, title = {{{FPGA implementation of a second-order convolutive blind signal separation algorithm}}}, year = {{2012}}, } @inproceedings{2101, author = {{Grawinkel, Matthias and Süß, Tim and Best, Georg and Popov, Ivan and Brinkmann, André}}, booktitle = {{Proc. Parallel Data Storage Workshop (PDSW)}}, pages = {{13--17}}, publisher = {{IEEE}}, title = {{{Towards Dynamic Scripted pNFS Layouts}}}, doi = {{10.1109/SC.Companion.2012.13}}, year = {{2012}}, } @article{2102, author = {{Gesing, Sandra and Grunzke, Richard and Krüger, Jens and Birkenheuer, Georg and Wewior, Martin and Schäfer, Patrick and Schuller, Bernd and Schuster, Johannes and Herres-Pawlis, Sonja and Breuers, Sebastian and Balaskó, Ákos and Kozlovszky, Miklos and Szikszay Fabri, Anna and Packschies, Lars and Kacsuk, Peter and Blunk, Dirk and Steinke, Thomas and Brinkmann, André and Fels, Gregor and Müller-Pfefferkorn, Ralph and Jäkel, René and Kohlbacher, Oliver}}, journal = {{Journal of Grid Computing}}, number = {{4}}, pages = {{769--790}}, publisher = {{Springer}}, title = {{{A Single Sign-On Infrastructure for Science Gateways on a Use Case for Structural Bioinformatics}}}, doi = {{10.1007/s10723-012-9247-y}}, volume = {{10}}, year = {{2012}}, } @inproceedings{2103, author = {{Wistuba, Martin and Schaefers, Lars and Platzner, Marco}}, booktitle = {{Proc. IEEE Conf. on Computational Intelligence and Games (CIG)}}, pages = {{91--99}}, publisher = {{IEEE}}, title = {{{Comparison of Bayesian Move Prediction Systems for Computer Go}}}, doi = {{10.1109/CIG.2012.6374143}}, year = {{2012}}, } @inproceedings{2104, author = {{Schlemmer, Tobias and Grunzke, Richard and Gesing, Sandra and Krüger, Jens and Birkenheuer, Georg and Müller-Pfefferkorn, Ralph and Kohlbacher, Oliver}}, booktitle = {{Proc. EGI Technical Forum}}, title = {{{Generic User Management for Science Gateways via Virtual Organizations}}}, year = {{2012}}, } @inproceedings{2105, author = {{Congiu, Giuseppe and Grawinkel, Matthias and Narasimhamurthy, Sai and Brinkmann, André}}, booktitle = {{Proc. Workshop on Interfaces and Architectures for Scientific Data Storage (IASDS)}}, pages = {{16--24}}, publisher = {{IEEE}}, title = {{{One Phase Commit: A Low Overhead Atomic Commitment Protocol for Scalable Metadata Services}}}, doi = {{10.1109/ClusterW.2012.16}}, year = {{2012}}, }