@article{13475, author = {{Timmer, F. and Oelke, R. and Dues, C. and Sanna, S. and Schmidt, Wolf Gero and Franz, M. and Appelfeller, S. and Dähne, M. and Wollschläger, J.}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, number = {{20}}, title = {{{Strain-induced quasi-one-dimensional rare-earth silicide structures on Si(111)}}}, doi = {{10.1103/physrevb.94.205431}}, volume = {{94}}, year = {{2016}}, } @article{15854, author = {{Lewandowski, Przemyslaw and Lafont, Ombline and Baudin, Emmanuel and Chan, Chris K. P. and Leung, P. T. and Luk, Samuel M. H. and Galopin, Elisabeth and Lemaître, Aristide and Bloch, Jacqueline and Tignon, Jerome and Roussignol, Philippe and Kwong, N. H. and Binder, Rolf and Schumacher, Stefan}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, title = {{{Polarization dependence of nonlinear wave mixing of spinor polaritons in semiconductor microcavities}}}, doi = {{10.1103/physrevb.94.045308}}, year = {{2016}}, } @article{15852, author = {{Niemietz, Dominik and Schmutzler, Johannes and Lewandowski, Przemyslaw and Winkler, Karol and Aßmann, Marc and Schumacher, Stefan and Brodbeck, Sebastian and Kamp, Martin and Schneider, Christian and Höfling, Sven and Bayer, Manfred}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, title = {{{Experimental realization of a polariton beam amplifier}}}, doi = {{10.1103/physrevb.93.235301}}, year = {{2016}}, } @article{15853, author = {{Yulin, A. V. and Chestnov, I. Yu. and Ma, X. and Schumacher, Stefan and Peschel, U. and Egorov, O. A.}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, title = {{{Dynamics of exciton-polaritons in discrete lattices under incoherent localized pumping}}}, doi = {{10.1103/physrevb.94.054312}}, year = {{2016}}, } @article{15856, author = {{Vollbrecht, Joachim and Wiebeler, Christian and Neuba, Adam and Bock, Harald and Schumacher, Stefan and Kitzerow, Heinz-Siegfried}}, issn = {{1932-7447}}, journal = {{The Journal of Physical Chemistry C}}, pages = {{7839--7848}}, title = {{{Bay-Extended, Distorted Perylene Esters Showing Visible Luminescence after Ultraviolet Excitation: Photophysical and Electrochemical Analysis}}}, doi = {{10.1021/acs.jpcc.6b00954}}, year = {{2016}}, } @article{15855, author = {{Kwong, N. H. and Tsang, C. Y. and Luk, M. H. and Tse, Y. C. and Lewandowski, P. and Chan, Chris K. P. and Leung, P. T. and Schumacher, Stefan and Binder, R.}}, issn = {{0740-3224}}, journal = {{Journal of the Optical Society of America B}}, title = {{{Patterns and switching dynamics in polaritonic quantum fluids in semiconductor microcavities [Invited]}}}, doi = {{10.1364/josab.33.00c153}}, year = {{2016}}, } @article{13815, abstract = {{

We report a combined experiment-theory study on low energy vibrational modes in fluorescence spectra of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) molecules.

}}, author = {{Paulheim, A. and Marquardt, C. and Sokolowski, M. and Hochheim, M. and Bredow, T. and Aldahhak, Hazem and Rauls, E. and Schmidt, Wolf Gero}}, issn = {{1463-9076}}, journal = {{Physical Chemistry Chemical Physics}}, pages = {{32891--32902}}, title = {{{Surface induced vibrational modes in the fluorescence spectra of PTCDA adsorbed on the KCl(100) and NaCl(100) surfaces}}}, doi = {{10.1039/c6cp05661j}}, volume = {{18}}, year = {{2016}}, } @article{13816, author = {{Yeom, Han Woong and Oh, Deok Mahn and Wippermann, Stefan and Schmidt, Wolf Gero}}, issn = {{1936-0851}}, journal = {{ACS Nano}}, pages = {{810--814}}, title = {{{Impurity-Mediated Early Condensation of a Charge Density Wave in an Atomic Wire Array}}}, doi = {{10.1021/acsnano.5b05925}}, volume = {{10}}, year = {{2016}}, } @article{1769, abstract = {{Große zylindrische Stahlprüflinge werden mittels der Methode der finiten Differenzen im Zeitbereich (engl. finite differences in time domain, FDTD) simulativ untersucht. Dabei werden Pitch-Catch-Messanordnungen verwendet. Es werden zwei Bildgebungsansätze vorgestellt: ersterer basiert auf dem Imaging Principle nach Claerbout, letzterer basiert auf gradientenbasierter Optimierung eines Zielfunktionals.}}, author = {{Hegler, Sebastian and Statz, Christoph and Mütze, Marco and Mooshofer, Hubert and Goldammer, Matthias and Fendt, Karl and Schwarzer, Stefan and Feldhoff, Kim and Flehmig, Martin and Markwardt, Ulf and E. Nagel, Wolfgang and Schütte, Maria and Walther, Andrea and Meinel, Michael and Basermann, Achim and Plettemeier, Dirk}}, journal = {{tm - Technisches Messen}}, number = {{9}}, pages = {{440--450}}, publisher = {{Walter de Gruyter}}, title = {{{Simulative Ultraschall-Untersuchung von Pitch-Catch-Messanordnungen für große zylindrische Stahl-Prüflinge und gradientenbasierte Bildgebung}}}, doi = {{doi:10.1515/teme-2015-0031}}, volume = {{82}}, year = {{2015}}, } @article{1772, author = {{Torresen, Jim and Plessl, Christian and Yao, Xin}}, journal = {{IEEE Computer}}, keywords = {{self-awareness, self-expression}}, number = {{7}}, pages = {{18--20}}, publisher = {{IEEE Computer Society}}, title = {{{Self-Aware and Self-Expressive Systems – Guest Editor's Introduction}}}, doi = {{10.1109/MC.2015.205}}, volume = {{48}}, year = {{2015}}, } @article{1774, abstract = {{In this article an efficient numerical method to solve multiobjective optimization problems for fluid flow governed by the Navier Stokes equations is presented. In order to decrease the computational effort, a reduced order model is introduced using Proper Orthogonal Decomposition and a corresponding Galerkin Projection. A global, derivative free multiobjective optimization algorithm is applied to compute the Pareto set (i.e. the set of optimal compromises) for the concurrent objectives minimization of flow field fluctuations and control cost. The method is illustrated for a 2D flow around a cylinder at Re = 100.}}, author = {{Peitz, Sebastian and Dellnitz, Michael}}, issn = {{1617-7061}}, journal = {{PAMM}}, number = {{1}}, pages = {{613--614}}, publisher = {{WILEY-VCH Verlag}}, title = {{{Multiobjective Optimization of the Flow Around a Cylinder Using Model Order Reduction}}}, doi = {{10.1002/pamm.201510296}}, volume = {{15}}, year = {{2015}}, } @misc{1794, abstract = {{Demands for computational power and energy efficiency of computing devices are steadily increasing. At the same time, following classic methods to increase speed and reduce energy consumption of these devices becomes increasingly difficult, bringing alternative methods into focus. One of these methods is approximate computing which utilizes the fact that small errors in computations are acceptable in many applications in order to allow acceleration of these computations or to increase energy efficiency. This thesis develops elements of a workflow that can be followed to apply approximate computing to existing applications. It proposes a novel heuristic approach to the localization of code paths that are suitable to approximate computing based on findings in recent research. Additionally, an approach to identification of approximable instructions within these code paths is proposed and used to implement simulation of approximation. The parts of the workflow are implemented with the goal to lay the foundation for a partly automated toolflow. Evaluation of the developed techniques shows that the proposed methods can help providing a convenient workflow, facilitating the first steps into the application of approximate computing.}}, author = {{Lass, Michael}}, publisher = {{Paderborn University}}, title = {{{Localization and Analysis of Code Paths Suitable for Acceleration using Approximate Computing}}}, year = {{2015}}, } @misc{5413, author = {{Funke, Lukas}}, publisher = {{Universität Paderborn}}, title = {{{An LLVM Based Toolchain for Transparent Acceleration of Digital Image Processing Applications using FPGA Overlay Architectures}}}, year = {{2015}}, } @misc{5416, author = {{Löcke, Thomas}}, publisher = {{Universität Paderborn}}, title = {{{Instance-Specific Computing in Hard- and Software for Faster Solving of Complex Problems}}}, year = {{2015}}, } @misc{5419, author = {{Wallaschek, Felix}}, publisher = {{Universität Paderborn}}, title = {{{Accelerating Programmable Logic Controllers with the use of FPGAs}}}, year = {{2015}}, } @phdthesis{10624, abstract = {{The use of heterogeneous computing resources, such as graphics processing units or other specialized co-processors, has become widespread in recent years because of their performance and energy efficiency advantages. Operating system approaches that are limited to optimizing CPU usage are no longer sufficient for the efficient utilization of systems that comprise diverse resource types. Enabling task preemption on these architectures and migration of tasks between different resource types at run-time is not only key to improving the performance and energy consumption but also to enabling automatic scheduling methods for heterogeneous compute nodes. This thesis proposes novel techniques for run-time management of heterogeneous resources and enabling tasks to migrate between diverse hardware. It provides fundamental work towards future operating systems by discussing implications, limitations, and chances of the heterogeneity and introducing solutions for energy- and performance-efficient run-time systems. Scheduling methods to utilize heterogeneous systems by the use of a centralized scheduler are presented that show benefits over existing approaches in varying case studies.}}, author = {{Beisel, Tobias}}, isbn = {{978-3-8325-4155-2}}, pages = {{183}}, publisher = {{Logos Verlag Berlin GmbH}}, title = {{{Management and Scheduling of Accelerators for Heterogeneous High-Performance Computing}}}, year = {{2015}}, } @article{296, abstract = {{FPGAs are known to permit huge gains in performance and efficiency for suitable applications but still require reduced design efforts and shorter development cycles for wider adoption. In this work, we compare the resulting performance of two design concepts that in different ways promise such increased productivity. As common starting point, we employ a kernel-centric design approach, where computational hotspots in an application are identified and individually accelerated on FPGA. By means of a complex stereo matching application, we evaluate two fundamentally different design philosophies and approaches for implementing the required kernels on FPGAs. In the first implementation approach, we designed individually specialized data flow kernels in a spatial programming language for a Maxeler FPGA platform; in the alternative design approach, we target a vector coprocessor with large vector lengths, which is implemented as a form of programmable overlay on the application FPGAs of a Convey HC-1. We assess both approaches in terms of overall system performance, raw kernel performance, and performance relative to invested resources. After compensating for the effects of the underlying hardware platforms, the specialized dataflow kernels on the Maxeler platform are around 3x faster than kernels executing on the Convey vector coprocessor. In our concrete scenario, due to trade-offs between reconfiguration overheads and exposed parallelism, the advantage of specialized dataflow kernels is reduced to around 2.5x.}}, author = {{Kenter, Tobias and Schmitz, Henning and Plessl, Christian}}, journal = {{International Journal of Reconfigurable Computing (IJRC)}}, publisher = {{Hindawi}}, title = {{{Exploring Tradeoffs between Specialized Kernels and a Reusable Overlay in a Stereo-Matching Case Study}}}, doi = {{10.1155/2015/859425}}, volume = {{2015}}, year = {{2015}}, } @inproceedings{303, abstract = {{This paper introduces Binary Acceleration At Runtime(BAAR), an easy-to-use on-the-fly binary acceleration mechanismwhich aims to tackle the problem of enabling existentsoftware to automatically utilize accelerators at runtime. BAARis based on the LLVM Compiler Infrastructure and has aclient-server architecture. The client runs the program to beaccelerated in an environment which allows program analysisand profiling. Program parts which are identified as suitable forthe available accelerator are exported and sent to the server.The server optimizes these program parts for the acceleratorand provides RPC execution for the client. The client transformsits program to utilize accelerated execution on the server foroffloaded program parts. We evaluate our work with a proofof-concept implementation of BAAR that uses an Intel XeonPhi 5110P as the acceleration target and performs automaticoffloading, parallelization and vectorization of suitable programparts. The practicality of BAAR for real-world examples is shownbased on a study of stencil codes. Our results show a speedup ofup to 4 without any developer-provided hints and 5.77 withhints over the same code compiled with the Intel Compiler atoptimization level O2 and running on an Intel Xeon E5-2670machine. Based on our insights gained during implementationand evaluation we outline future directions of research, e.g.,offloading more fine-granular program parts than functions, amore sophisticated communication mechanism or introducing onstack-replacement.}}, author = {{Damschen, Marvin and Plessl, Christian}}, booktitle = {{Proceedings of the 5th International Workshop on Adaptive Self-tuning Computing Systems (ADAPT)}}, title = {{{Easy-to-Use On-The-Fly Binary Program Acceleration on Many-Cores}}}, year = {{2015}}, } @inproceedings{1773, author = {{Schumacher, Jörn and T. Anderson, J. and Borga, A. and Boterenbrood, H. and Chen, H. and Chen, K. and Drake, G. and Francis, D. and Gorini, B. and Lanni, F. and Lehmann-Miotto, Giovanna and Levinson, L. and Narevicius, J. and Plessl, Christian and Roich, A. and Ryu, S. and P. Schreuder, F. and Vandelli, Wainer and Vermeulen, J. and Zhang, J.}}, booktitle = {{Proc. Int. Conf. on Distributed Event-Based Systems (DEBS)}}, publisher = {{ACM}}, title = {{{Improving Packet Processing Performance in the ATLAS FELIX Project – Analysis and Optimization of a Memory-Bounded Algorithm}}}, doi = {{10.1145/2675743.2771824}}, year = {{2015}}, } @article{1768, author = {{Plessl, Christian and Platzner, Marco and Schreier, Peter J.}}, journal = {{Informatik Spektrum}}, keywords = {{approximate computing, survey}}, number = {{5}}, pages = {{396--399}}, publisher = {{Springer}}, title = {{{Aktuelles Schlagwort: Approximate Computing}}}, doi = {{10.1007/s00287-015-0911-z}}, year = {{2015}}, }