Signal Detection for QPSK Based Cognitive Radio Systems using Support Vector Machines

Cognitive radio based network enables opportunistic dynamic spectrum access by sensing, adopting and utilizing the unused portion of licensed spectrum bands. Cognitive radio is intelligent enough to adapt the communication parameters of the unused licensed spectrum. Spectrum sensing is one of the most important tasks of the cognitive radio cycle. In this paper, the auto-correlation function kernel based Support Vector Machine (SVM) classifier along with Welch's Periodogram detector is successfully implemented for the detection of four QPSK (Quadrature Phase Shift Keying) based signals propagating through an AWGN (Additive White Gaussian Noise) channel. It is shown that the combination of statistical signal processing and machine learning concepts improve the spectrum sensing process and spectrum sensing is possible even at low Signal to Noise Ratio (SNR) values up to -50 dB

Microscopic HFB+QRPA predictions of dipole strength for astrophysics applications

Large-scale QRPA calculations of the E1 strength are performed on top of HFB calculations in order to derive the radiative neutron capture cross sections for the whole nuclear chart. The spreading width of the GDR is taken into account by analogy with the second-RPA (SRPA) method. The accuracy of HFB+QRPA model based on various Skyrme forces with different pairing prescription and parameterization is analyzed. It is shown that the present model allows to constrain the effective nucleon-nucleon interaction with the GDR data and to provide quantitative predictions of dipole strengths.Comment: 21 pages, 9 figure

Extra ZZ bosons and low-energy tests of unification

If there is an extra U(1) gauge symmetry broken at low energies, then it may be possible from the charges of the known quarks and leptons under this U(1) to make inferences about how much gauge unification occurs at high scales and about the unification group. (For instance, there are certain observed properties of an extra $U(1)'$ that would be inconsistent with unification in four dimensions at high scales.) A general analysis is presented. Two criteria used in this analysis are (1) the degree to which the generator of the extra U(1) mixes with hypercharge, and (2) the ratio of the extra U(1) charge of the "10" and the "$\bar{5}$" of quarks and leptons.Comment: 27 pages, LaTex, no figures. Changed content. References added. Typos correcte