2,537 research outputs found

    Evaluating Rapid Application Development with Python for Heterogeneous Processor-based FPGAs

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    As modern FPGAs evolve to include more het- erogeneous processing elements, such as ARM cores, it makes sense to consider these devices as processors first and FPGA accelerators second. As such, the conventional FPGA develop- ment environment must also adapt to support more software- like programming functionality. While high-level synthesis tools can help reduce FPGA development time, there still remains a large expertise gap in order to realize highly performing implementations. At a system-level the skill set necessary to integrate multiple custom IP hardware cores, interconnects, memory interfaces, and now heterogeneous processing elements is complex. Rather than drive FPGA development from the hardware up, we consider the impact of leveraging Python to ac- celerate application development. Python offers highly optimized libraries from an incredibly large developer community, yet is limited to the performance of the hardware system. In this work we evaluate the impact of using PYNQ, a Python development environment for application development on the Xilinx Zynq devices, the performance implications, and bottlenecks associated with it. We compare our results against existing C-based and hand-coded implementations to better understand if Python can be the glue that binds together software and hardware developers.Comment: To appear in 2017 IEEE 25th Annual International Symposium on Field-Programmable Custom Computing Machines (FCCM'17

    Temperature variation of the resistivity of metallic strain gauge materials Final report

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    Temperature effects on electrical resistivity of metallic strain gage material

    Nonperturbative ``Lattice Perturbation Theory''

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    We discuss a program for replacing standard perturbative methods with Monte Carlo simulations in short distance lattice gauge theory calculations.Comment: 3 pages, uuencoded Latex file, two embedded figures and .sty file include

    International Health Research and the Emergence of Global Health in the Late Twentieth Century

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    An influential policy network emerged from two overlapping developments of the 1970s and 1980s: new research programs focusing on tropical diseases and debates about how to implement the concept of primary health care at the World Health Organization. Participating actors came together in an informal network that, by the late 1980s, expanded advocacy to include the promotion and reorganization of all forms of research that might improve health in the Global South. This goal became associated with a search for new research methods for determining priorities, a quest that reached a peak in the early 1990s when the World Bank entered the picture. The bank brought money, economic analyses, and neoliberal ideology to the research advocacy movement and helped stimulate an upsurge of cost-effective forms of economic thinking in global health (GH) circles. This expanded research network provided some of the conceptual foundations and leadership for several of the most emblematic institutions of the new GH. These included new organizations to bring together and coordinate public and private actors in pursuit of common aims and new forms of economic rationality. The network's advocacy work contributed as well to a massive expansion of GH research at the turn of the century

    The SU(3) deconfining phase transition with Symanzik action

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    We report on the determination of the deconfining temperature in SU(3) pure gauge theory, using the Symanzik tree level improved action, on lattices of size 3 x 12^3, 4 x 16^3, 5 x 20^3, 6 x24^3. We find that the asymptotic scaling violation pattern is similar to the one observed using the Wilson action. We conclude that the irrelevant operators do not affect, in the range of couplings considered, the lattice beta function. An analysis based on an effective coupling formulation shows an apparent improvement.Comment: 8 pages, report IFUP-TH 12/9

    Perturbative calculation of improvement coefficients to O(g^2a) for bilinear quark operators in lattice QCD

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    We calculate the O(g^2 a) mixing coefficients of bilinear quark operators in lattice QCD using a standard perturbative evaluation of on-shell Green's functions. Our results for the plaquette gluon action are in agreement with those previously obtained with the Schr\"odinger functional method. The coefficients are also calculated for a class of improved gluon actions having six-link terms.Comment: 14 pages, REVTe

    Perturbative Renormalization Factors of Bilinear Quark Operators for Improved Gluon and Quark Actions in Lattice QCD

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    We calculate one-loop renormalization factors of bilinear quark operators for gluon action including six-link loops and O(a)O(a)-improved quark action in the limit of massless quark. We find that finite parts of one-loop coefficients of renormalization factors diminish monotonically as either of the coefficients c1c_1 or c2+c3c_2+c_3 of the six-link terms are decreased below zero. Detailed numerical results are given, for general values of the clover coefficient, for the tree-level improved gluon action in the Symanzik approach (c1=−1/12,c2=c3=0)(c_1=-1/12, c_2=c_3=0) and for the choices suggested by Wilson (c1=−0.252,c2=0,c3=−0.17)(c_1=-0.252, c_2=0, c_3=-0.17) and by Iwasaki (c1=−0.331,c2=c3=0(c_1=-0.331, c_2=c_3=0 and c1=−0.27,c2+c3=−0.04)c_1=-0.27, c_2+c_3=-0.04) from renormalization-group analyses. Compared with the case of the standard plaquette gluon action, finite parts of one-loop coefficients are reduced by 10--20% for the Symanzik action, and approximately by a factor two for the renormalization-group improved gluon actions.Comment: 19 pages, REVTeX, with 3 epsf figure

    ATP-dependent chromatosome remodeling

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    Chromatin serves to package, protect and organize the complex eukaryotic genomes to assure their stable inheritance over many cell generations. At the same time, chromatin must be dynamic to allow continued use of DNA during a cell's lifetime. One important principle that endows chromatin with flexibility involves ATP-dependent `remodeling' factors, which alter DNA-histone interactions to form, disrupt or move nucleosomes. Remodeling is well documented at the nucleosomal level, but little is known about the action of remodeling factors in a more physiological chromatin environment. Recent findings suggest that some remodeling machines can reorganize even folded chromatin fibers containing the linker histone H1, extending the potential scope of remodeling reactions to the bulk of euchromatin

    Quark-gluon vertex in a momentum subtraction scheme

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    We compute the quark-gluon vertex in quenched QCD, in the Landau gauge using an off-shell mean-field O(a)-improved fermion action. The running coupling is calculated in an `asymmetric' momentum subtraction scheme (MOM~). We obtain a crude estimate for Lambda_MSbar=170+/-65 MeV, which is considerably lower than other determinations of this quantity. However, substantial systematic errors remain.Comment: Lattice2001(improvement); 3 pages, 3 figure

    A quark action for very coarse lattices

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    We investigate a tree-level O(a^3)-accurate action, D234c, on coarse lattices. For the improvement terms we use tadpole-improved coefficients, with the tadpole contribution measured by the mean link in Landau gauge. We measure the hadron spectrum for quark masses near that of the strange quark. We find that D234c shows much better rotational invariance than the Sheikholeslami-Wohlert action, and that mean-link tadpole improvement leads to smaller finite-lattice-spacing errors than plaquette tadpole improvement. We obtain accurate ratios of lattice spacings using a convenient ``Galilean quarkonium'' method. We explore the effects of possible O(alpha_s) changes to the improvement coefficients, and find that the two leading coefficients can be independently tuned: hadron masses are most sensitive to the clover coefficient, while hadron dispersion relations are most sensitive to the third derivative coefficient C_3. Preliminary non-perturbative tuning of these coefficients yields values that are consistent with the expected size of perturbative corrections.Comment: 22 pages, LaTe
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