@article{13834, author = {{Sanna, Simone and Schmidt, Wolf Gero}}, issn = {{0169-4332}}, journal = {{Applied Surface Science}}, pages = {{5740--5743}}, title = {{{GaN/LiNbO3 (0001) interface formation calculated from first-principles}}}, doi = {{10.1016/j.apsusc.2010.03.098}}, volume = {{256}}, year = {{2010}}, } @article{13826, author = {{Blankenburg, S. and Rauls, E. and Schmidt, Wolf Gero}}, issn = {{1948-7185}}, journal = {{The Journal of Physical Chemistry Letters}}, pages = {{3266--3270}}, title = {{{Catalytic Action of a Cu(111) Surface on Tetraazaperopyrene Polymerization}}}, doi = {{10.1021/jz101389u}}, volume = {{1}}, year = {{2010}}, } @article{15846, author = {{Schumacher, Stefan and Galbraith, Ian and Ruseckas, Arvydas and Turnbull, Graham A. and Samuel, Ifor D. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, title = {{{Dynamics of photoexcitation and stimulated optical emission in conjugated polymers: A multiscale quantum-chemistry and Maxwell-Bloch-equations approach}}}, doi = {{10.1103/physrevb.81.245407}}, year = {{2010}}, } @article{4169, abstract = {{It is demonstrated that valence-band mixing in GaAs quantum wells tremendously modifies electronic transport. A coherent control scheme in which ultrafast currents are optically injected into undoped GaAs quantum wells upon excitation with femtosecond laser pulses is employed. An oscillatory dependence of the injection current amplitude and direction on the excitation photon energy is observed. A microscopic theoretical analysis shows that this current reversal is caused by the coupling of the light- and heavy-hole bands and that the hole currents dominate the overall current response. These surprising consequences of band mixing illuminate fundamental physics as they are unique for experiments which are able to monitor electronic transport resulting from carriers with relatively large momenta.}}, author = {{Priyadarshi, S. and Racu, A. M. and Pierz, K. and Siegner, U. and Bieler, M. and Duc, H. T. and Förstner, Jens and Meier, Torsten}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, keywords = {{tet_topic_qw}}, number = {{21}}, publisher = {{American Physical Society (APS)}}, title = {{{Reversal of Coherently Controlled Ultrafast Photocurrents by Band Mixing in Undoped GaAs Quantum Wells}}}, doi = {{10.1103/physrevlett.104.217401}}, volume = {{104}}, year = {{2010}}, } @article{4172, abstract = {{Microdisks made from GaAs with embedded InAs quantum dots are immersed in the liquid crystal 4-cyano-4’-pentylbiphenyl (5CB). The quantum dots serve as emitters feeding the optical modes of the photonic cavity. By changing temperature, the liquid crystal undergoes a phase transition from the isotropic to the nematic state, which can be used as an effective tuning mechanism of the photonic modes of the cavity. In the nematic state, the uniaxial electrical anisotropy of the liquid crystal molecules can be exploited for orienting the material in an electric field, thus externally controlling the birefringence of the material. Using this effect, an electric field induced tuning of the modes is achieved. Numerical simulations using the finite-differences time-domain (FDTD) technique employing an anisotropic dielectric medium allow to understand the alignment of the liquid crystal molecules on the surface of the microdisk resonator.}}, author = {{Piegdon, Karoline A. and Declair, Stefan and Förstner, Jens and Meier, Torsten and Matthias, Heiner and Urbanski, Martin and Kitzerow, Heinz-Siegfried and Reuter, Dirk and Wieck, Andreas D. and Lorke, Axel and Meier, Cedrik}}, issn = {{1094-4087}}, journal = {{Optics Express}}, keywords = {{tet_topic_qd, tet_topic_microdisk}}, number = {{8}}, publisher = {{The Optical Society}}, title = {{{Tuning quantum-dot based photonic devices with liquid crystals}}}, doi = {{10.1364/oe.18.007946}}, volume = {{18}}, year = {{2010}}, } @techreport{2353, abstract = {{Wireless Sensor Networks (WSNs) are unique embedded computation systems for distributed sensing of a dispersed phenomenon. While being a strongly concurrent distributed system, its embedded aspects with severe resource limitations and the wireless communication requires a fusion of technologies and methodologies from very different fields. As WSNs are deployed in remote locations for long-term unattended operation, assurance of correct functioning of the system is of prime concern. Thus, the design and development of WSNs requires specialized tools to allow for testing and debugging the system. To this end, we present a framework for analyzing and checking WSNs based on collected events during system operation. It allows for abstracting from the event trace by means of behavioral queries and uses assertions for checking the accordance of an execution to its specification. The framework is independent from WSN test platforms, applications and logging semantics and thus generally applicable for analyzing event logs of WSN test executions. }}, author = {{Woehrle, Matthias and Plessl, Christian and Thiele, Lothar}}, keywords = {{Rupeas, DSL, WSN, testing}}, title = {{{Rupeas: Ruby Powered Event Analysis DSL}}}, year = {{2009}}, } @article{2354, author = {{Brinkmann, André and Eschweiler, Dominic}}, journal = {{Journal of Supercomputing}}, pages = {{35:1--35:10}}, publisher = {{ACM}}, title = {{{A Microdriver Architecture for Error Correcting Codes inside the Linux Kernel}}}, doi = {{10.1145/1654059.1654095}}, year = {{2009}}, } @inproceedings{2239, author = {{Höing, Andre and Scherp, Guido and Gudenkauf, Stefan and Meister, Dirk and Brinkmann, André}}, booktitle = {{Proc. Int. Conf. on Service Oriented Computing (ICSOC)}}, pages = {{301--315}}, publisher = {{Springer}}, title = {{{An Orchestration as a Service Infrastructure using Grid Technologies and WS-BPEL}}}, doi = {{0.1007/978-3-642-10383-4_20}}, volume = {{5900}}, year = {{2009}}, } @inproceedings{2240, author = {{Niehörster, Oliver and Birkenheuer, Georg and Brinkmann, André and Blunk, Dirk and Elsässer, Brigitta and Herres-Pawlis, Sonja and Krüger, Jens and Niehörster, Julia and Packschies, Lars and Fels, Gregor}}, booktitle = {{Proc. Cracow Grid Workshop (CGW)}}, isbn = {{978-83-61433-01-9}}, pages = {{55--63}}, title = {{{Providing Scientific Software as a Service in Consideration of Service Level Agreements}}}, year = {{2009}}, } @inproceedings{2260, author = {{Birkenheuer, Georg and Carlson, Arthur and Fölling, Alexander and Högqvist, Mikael and Hoheisel, Andreas and Papaspyrou, Alexander and Rieger, Klaus and Schott, Bernhard and Ziegler, Wolfgang}}, booktitle = {{Proc. Cracow Grid Workshop (CGW)}}, isbn = {{978-83-61433-01-9}}, pages = {{96--103}}, title = {{{Connecting Communities on the Meta-Scheduling Level: The DGSI Approach!}}}, year = {{2009}}, } @inproceedings{2264, author = {{Meister, Dirk and Brinkmann, André}}, booktitle = {{Proc. of the Israeli Experimental Systems Conference (SYSTOR)}}, pages = {{8:1--8:12}}, publisher = {{ACM}}, title = {{{Multi-Level Comparison of Data Deduplication in a Backup Scenario}}}, doi = {{10.1145/1534530.1534541}}, year = {{2009}}, } @inproceedings{818, author = {{Birkenheuer, Georg and Brinkmann, Andre and Karl, Holger}}, booktitle = {{Job Scheduling Strategies for Parallel Processing, 14th International Workshop, JSSPP 2009, Rome, Italy, May 29, 2009. Revised Papers}}, pages = {{80--100}}, title = {{{The Gain of Overbooking}}}, doi = {{10.1007/978-3-642-04633-9_5}}, year = {{2009}}, } @inproceedings{2350, abstract = {{Mapping applications that consist of a collection of cores to FPGA accelerators and optimizing their performance is a challenging task in high performance reconfigurable computing. We present IMORC, an architectural template and highly versatile on-chip interconnect. IMORC links provide asynchronous FIFOs and bitwidth conversion which allows for flexibly composing accelerators from cores running at full speed within their own clock domains, thus facilitating the re-use of cores and portability. Further, IMORC inserts performance counters for monitoring runtime data. In this paper, we first introduce the IMORC architectural template and the on-chip interconnect, and then demonstrate IMORC on the example of accelerating the k-th nearest neighbor thinning problem on an XD1000 reconfigurable computing system. Using IMORC's monitoring infrastructure, we gain insights into the data-dependent behavior of the application which, in turn, allow for optimizing the accelerator. }}, author = {{Schumacher, Tobias and Plessl, Christian and Platzner, Marco}}, booktitle = {{Proc. Int. Symp. on Field-Programmable Custom Computing Machines (FCCM)}}, isbn = {{978-1-4244-4450-2}}, keywords = {{IMORC, interconnect, performance}}, pages = {{275--278}}, publisher = {{IEEE Computer Society}}, title = {{{IMORC: Application Mapping, Monitoring and Optimization for High-Performance Reconfigurable Computing}}}, doi = {{10.1109/FCCM.2009.25}}, year = {{2009}}, } @inproceedings{2262, abstract = {{In this work we present EvoCache, a novel approach for implementing application-specific caches. The key innovation of EvoCache is to make the function that maps memory addresses from the CPU address space to cache indices programmable. We support arbitrary Boolean mapping functions that are implemented within a small reconfigurable logic fabric. For finding suitable cache mapping functions we rely on techniques from the evolvable hardware domain and utilize an evolutionary optimization procedure. We evaluate the use of EvoCache in an embedded processor for two specific applications (JPEG and BZIP2 compression) with respect to execution time, cache miss rate and energy consumption. We show that the evolvable hardware approach for optimizing the cache functions not only significantly improves the cache performance for the training data used during optimization, but that the evolved mapping functions generalize very well. Compared to a conventional cache architecture, EvoCache applied to test data achieves a reduction in execution time of up to 14.31% for JPEG (10.98% for BZIP2), and in energy consumption by 16.43% for JPEG (10.70% for BZIP2). We also discuss the integration of EvoCache into the operating system and show that the area and delay overheads introduced by EvoCache are acceptable. }}, author = {{Kaufmann, Paul and Plessl, Christian and Platzner, Marco}}, booktitle = {{Proc. NASA/ESA Conference on Adaptive Hardware and Systems (AHS)}}, keywords = {{EvoCache, evolvable hardware, computer architecture}}, pages = {{11--18}}, publisher = {{IEEE Computer Society}}, title = {{{EvoCaches: Application-specific Adaptation of Cache Mapping}}}, year = {{2009}}, } @inproceedings{2352, author = {{Beutel, Jan and Gruber, Stephan and Hasler, Andi and Lim, Roman and Meier, Andreas and Plessl, Christian and Talzi, Igor and Thiele, Lothar and Tschudin, Christian and Woehrle, Matthias and Yuecel, Mustafa}}, booktitle = {{Proc. Int. Conf. on Information Processing in Sensor Networks (IPSN)}}, isbn = {{978-1-4244-5108-1}}, keywords = {{WSN, PermaSense}}, pages = {{265--276}}, publisher = {{IEEE Computer Society}}, title = {{{PermaDAQ: A Scientific Instrument for Precision Sensing and Data Recovery in Environmental Extremes}}}, year = {{2009}}, } @inproceedings{2238, author = {{Schumacher, Tobias and Süß, Tim and Plessl, Christian and Platzner, Marco}}, booktitle = {{Proc. Int. Conf. on ReConFigurable Computing and FPGAs (ReConFig)}}, isbn = {{978-0-7695-3917-1}}, keywords = {{IMORC, graphics}}, pages = {{119--124}}, publisher = {{IEEE Computer Society}}, title = {{{Communication Performance Characterization for Reconfigurable Accelerator Design on the XD1000}}}, doi = {{10.1109/ReConFig.2009.32}}, year = {{2009}}, } @inproceedings{2261, author = {{Schumacher, Tobias and Plessl, Christian and Platzner, Marco}}, booktitle = {{Proc. Int. Conf. on Field Programmable Logic and Applications (FPL)}}, isbn = {{978-1-4244-3892-1}}, issn = {{1946-1488}}, keywords = {{IMORC, NOC, KNN, accelerator}}, pages = {{338--344}}, publisher = {{IEEE}}, title = {{{An Accelerator for k-th Nearest Neighbor Thinning Based on the IMORC Infrastructure}}}, year = {{2009}}, } @inproceedings{2263, abstract = {{In this paper, we introduce the Woolcano reconfigurable processor architecture. The architecture is based on the Xilinx Virtex-4 FX FPGA and leverages the Auxiliary Processing Unit (APU) as well as the partial reconfiguration capabilities to provide dynamically reconfigurable custom instructions. We also present a hardware tool flow that automatically translates software functions into custom instructions and a software tool flow that creates binaries using these instructions. While previous research on processors with reconfigurable functional units has been performed predominantly with simulation, the Woolcano architecture allows for exploring dynamic instruction set extension with commercially available hardware. Finally, we present a case study demonstrating a custom floating-point instruction generated with our approach, which achieves a 40x speedup over software-emulated floating-point operations and a 21% speedup over the Xilinx hardware floating-point unit. }}, author = {{Grad, Mariusz and Plessl, Christian}}, booktitle = {{Proc. Int. Conf. on Engineering of Reconfigurable Systems and Algorithms (ERSA)}}, isbn = {{1-60132-101-5}}, pages = {{319--322}}, publisher = {{CSREA Press}}, title = {{{Woolcano: An Architecture and Tool Flow for Dynamic Instruction Set Extension on Xilinx Virtex-4 FX}}}, year = {{2009}}, } @article{15847, author = {{Kwong, N. H. and Schumacher, Stefan and Binder, R.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, title = {{{Electron-Spin Beat Susceptibility of Excitons in Semiconductor Quantum Wells}}}, doi = {{10.1103/physrevlett.103.056405}}, year = {{2009}}, } @article{13580, author = {{Wippermann, S. and Schmidt, Wolf Gero and Thissen, P. and Grundmeier, Guido}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{137--140}}, title = {{{Dissociative and molecular adsorption of water onα-Al2O3(0001)}}}, doi = {{10.1002/pssc.200982423}}, volume = {{7}}, year = {{2009}}, }