52,255 research outputs found

    A Simplified Scheme of Estimation and Cancellation of Companding Noise for Companded Multicarrier Transmission Systems

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    Nonlinear companding transform is an efficient method to reduce the high peak-to-average power ratio (PAPR) of multicarrier transmission systems. However, the introduced companding noise greatly degrades the bit-error-rate (BER) performance of the companded multicarrier systems. In this paper, a simplified but effective scheme of estimation and cancellation of companding noise for the companded multicarrier transmission system is proposed. By expressing the companded signals as the summation of original signals added with a companding noise component, and subtracting this estimated companding noise from the received signals, the BER performance of the overall system can be significantly improved. Simulation results well confirm the great advantages of the proposed scheme over other conventional decompanding or no decompanding schemes under various situations

    The Role of Traditional Birth Attendants in Family Planning Programs in Southeast Asia

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    The training and utilization of traditional birth attendants (TBAs) in maternal and child health and family planning programs in Indonesia, the Philippines, Thailand and Malaysia are discussed. Special efforts to organize and train TBAs for family planning in Malaysia are examined in detail. Import factors for successful utilization of TBAs include: (a) definite assignment of functions and tasks, (b) organization of good operational steps and (c) implementation of good supervisory activities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135477/1/ijgo00128.pd

    Orbital elements of barium stars formed through a wind accretion scenario

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    Taking the total angular momentum conservation in place of the tangential momentum conservation, and considering the square and higher power terms of orbital eccentricity e, the changes of orbital elements of binaries are calculated for wind accretion scenario. These new equations are used to quantitatively explain the observed (e,logP) properties of normal G, K giants and barium stars. Our results reflect the evolution from G, K giant binaries to barium binaries, moreover, the barium stars with longer orbital periods P>1600 days may be formed by accreting part of the ejecta from the intrinsic AGB stars through wind accretion scenario.Comment: 7 pages, LaTex, 4 PS figures and 1 table included, accepted for publication in A &

    Modified Bethe-Peierls boundary condition for ultracold atoms with Spin-Orbit coupling

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    We show that the Bethe-Peierls (BP) boundary condition should be modified for ultracold atoms with spin-orbit (SO) coupling. Moreover, we derive a general form of the modified BP boundary condition, which is applicable to a system with arbitrary kind of SO coupling. In the modified BP condition, an anisotropic term appears and the inter-atomic scattering length is normally SO-coupling dependent. For the special system in the current experiments, however, it can be proved that the scattering length is SO-coupling independent, and takes the same value as in the case without SO coupling. Our result is helpful for the study of both few-body and many-body physics in SO-coupled ultracold gases.Comment: 8 pages, significant improvement is made in the current versio
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