5,446 research outputs found
Analysis of Minimal LDPC Decoder System on a Chip Implementation
This paper presents a practical method of potential replacement of several different Quasi-Cyclic Low-Density Parity-Check (QC-LDPC) codes with one, with the intention of saving as much memory as required to implement the LDPC encoder and decoder in a memory-constrained System on a Chip (SoC). The presented method requires only a very small modification of the existing encoder and decoder, making it suitable for utilization in a Software Defined Radio (SDR) platform. Besides the analysis of the effects of necessary variable-node value fixation during the Belief Propagation (BP) decoding algorithm, practical standard-defined code parameters are scrutinized in order to evaluate the feasibility of the proposed LDPC setup simplification. Finally, the error performance of the modified system structure is evaluated and compared with the original system structure by means of simulation
Syzygies of torsion bundles and the geometry of the level l modular variety over M_g
We formulate, and in some cases prove, three statements concerning the purity
or, more generally the naturality of the resolution of various rings one can
attach to a generic curve of genus g and a torsion point of order l in its
Jacobian. These statements can be viewed an analogues of Green's Conjecture and
we verify them computationally for bounded genus. We then compute the
cohomology class of the corresponding non-vanishing locus in the moduli space
R_{g,l} of twisted level l curves of genus g and use this to derive results
about the birational geometry of R_{g, l}. For instance, we prove that R_{g,3}
is a variety of general type when g>11 and the Kodaira dimension of R_{11,3} is
greater than or equal to 19. In the last section we explain probabilistically
the unexpected failure of the Prym-Green conjecture in genus 8 and level 2.Comment: 35 pages, appeared in Invent Math. We correct an inaccuracy in the
statement of Prop 2.
Analysis of Aperture-coupled Microstrip Antenna Using Method of Moments
A microstrip patch antenna that is coupled to a microstripline by an aperture in the intervening ground plane is analyzed by using the method of moments. Integral equation is formulated by considering the exact dyadic Green's function in spectral domain for grounded dielectric slab so that the analysis includes all coupling effects and the radiation and surface wave effects of both substrates. The combination of the reciprocity method analysis and a Galerkin moment method solution seems to be suitable for a number of planar antenna problems, especially when coupling slots in the ground plane are included. Results for antenna input impedance are compared with other authors and verified by experimental results
Using of bioethanol fuels in ic engine
Renewables - excluding large hydro accounted for 48% - increased to 15.2% of world cumulative generation capacity in 2014, from 13.8% in 2013. In the EU, the European Parliament approved a reform of the 2020 biofuels target. The new version of the Renewable Energy Directive (RED) distributes the 10% cal. biofuels target into a share for cropbased biofuel (limited at 7% cal.) with the rest to be met with another biofuels and renewable electricity containing multiple counting possibilities.[7] Merely 2% of the EUâs fuel consumption can be covered by its own researches, which looks good pretend a strong dependence on the oil exporting countries. The implementations of biogenic fuels produced from fast growing plant is continuously gaining in importance with regard to economic and environmental effects. Generally they are not offered in their pure form but just as blend components to conventional fuels. [1][3][4] Their mixtures can bring about fundamental feature improvements.[2][5][6] Ethanol fuel output in 2015 reached a peak high helped by rising gasoline demand in the US. Besides, the changes in the fuel taxation in Brazil and an increase in the minimum blending ratio also pushed along the ethanol fuel demand. The weaker euro and low grain prices on the back of a record wheat crop turned into a considerable growth in output in the EU. Disregard the stimulating developments on the legislative side, it must also be confessed that the decreasing crude oil prices took their customs on the 2015 biofuel markets. For ethanol fuel, more growth could theoretically arrive from an extending of E-10 in EU member states. Unnecessary to discuss that an outlook for a post-2020 biofuels target at the EU level does not valid [8][9]
Investigation of alpha-induced reactions on 130Ba and 132Ba and their importance for the synthesis of heavy p nuclei
Captures of alpha particles on the proton-richest Barium isotope, 130Ba, have
been studied in order to provide cross section data for the modeling of the
astrophysical gamma process. The cross sections of the 130Ba(alpha,gamma)134Ce
and 130Ba(alpha,n)133Ce reactions have been measured with the activation
technique in the center-of mass energy range between 11.6 and 16 MeV, close
above the astrophysically relevant energies. As a side result, the cross
section of the 132Ba(alpha,n)135Ce reaction has also been measured. The results
are compared with the prediction of statistical model calculations, using
different input parameters such as alpha+nucleus optical potentials. It is
found that the (alpha,n) data can be reproduced employing the standard
alpha+nucleus optical potential widely used in astrophysical applications.
Assuming its validity also in the astrophysically relevant energy window, we
present new stellar reaction rates for 130Ba(alpha,gamma)134Ce and
132Ba(alpha,gamma)136Ce and their inverse reactions calculated with the SMARAGD
statistical model code. The highly increased 136Ce(gamma,alpha)132Ba rate
implies that the p nucleus 130Ba cannot directly receive contributions from the
Ce isotopic chain. Further measurements are required to better constrain this
result.Comment: Accepted for publication in Phys. Rev.
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