228 research outputs found

    H

    Get PDF
    This paper is concerned with the H∞ filtering problem for networked systems with bounded measurement missing. A switched linear system model is proposed to describe the considered filtering error system. A sufficient condition is derived for the filtering error system to be exponentially stable and achieve a prescribed H∞ filtering performance level. The obtained condition establishes quantitative relations among the H∞ performance level and two parameters characterizing the measurement missing, namely, the measurement missing rate bound and the maximal number of consecutive measurement missing. A convex optimization problem is presented to design the linear H∞ filters. Finally, an illustrative example is given to show the effectiveness of the proposed results

    The Milky Way's rotation curve out to 100 kpc and its constraint on the Galactic mass distribution

    Full text link
    The rotation curve (RC) of the Milky Way out to \sim 100 kpc has been constructed using \sim 16,000 primary red clump giants (PRCGs) in the outer disk selected from the LSS-GAC and the SDSS-III/APOGEE survey, combined with \sim 5700 halo K giants (HKGs) selected from the SDSS/SEGUE survey. To derive the RC, the PRCG sample of the warm disc population and the HKG sample of halo stellar population are respectively analyzed using a kinematical model allowing for the asymmetric drift corrections and re-analyzed using the spherical Jeans equation along with measurements of the anisotropic parameter β\beta currently available. The typical uncertainties of RC derived from the PRCG and HKG samples are respectively 5-7 km/s and several tens km/s. We determine a circular velocity at the solar position, Vc(R0)V_c (R_0) = 240 ±\pm 6 km/s and an azimuthal peculiar speed of the Sun, VV_{\odot} = 12.1 ±\pm 7.6 km/s, both in good agreement with the previous determinations. The newly constructed RC has a generally flat value of 240 km/s within a Galactocentric distance rr of 25 kpc and then decreases steadily to 150 km/s at rr \sim 100 kpc. On top of this overall trend, the RC exhibits two prominent localized dips, one at rr \sim 11 kpc and another at rr \sim 19 kpc. From the newly constructed RC, combined with other constraints, we have built a parametrized mass model for the Galaxy, yielding a virial mass of the Milky Way's dark matter halo of 0.900.08+0.07×10120.90^{+0.07}_{-0.08} \times 10^{12} M{\rm M}_{\odot} and a local dark matter density, ρ,dm=0.320.02+0.02\rho_{\rm \odot, dm} = 0.32^{+0.02}_{-0.02} GeV cm3^{-3}.Comment: MNRAS accepted, 18 pages, 15 figures, 4 table

    A curve model for association of serum homocysteine with carotid artery hemodynamics

    Get PDF
    Purpose: To investigate the correlation between carotid artery hemodynamics and serum homocysteine.Methods: A total of 894 participants made up of 439 male (49.11 %) and 455 female (50.89 %) from Ma’anshan, China, enrolled in the cross-sectional study. Data collection included demographics, blood sample and carotid ultrasonography. Piecewise linear regression analysis was used to analyze the relationship between serum homocysteine and carotid artery hemodynamics.Results: Homocysteine (Hcy) levels were divided into four groups by quartiles. The populations of the groups were 226, 220, 222, 226; and their mean ages were 56.52 ± 10.49, 62.27 ± 10.06, 63.42 ± 9.81 and 65.38 ± 10.56 years, respectively. After adjustment for blood biochemical and demographics factors, U-shaped and S-shaped curves were as observed between Hcy and carotid artery hemodynamics. The adjusted regression analysis showed that the threshold values of Hcy with end diastolic velocity (EDV) of right common carotid artery (CCA) were 12.50 and 19.00, while for the EDV of right internal carotid artery (ICA), the values were 11.50 and 22.00. U-shaped curves were observed between Hcy and peak systolic velocity (PSV) of left CCA, EDV of left CCA, PSV of left ICA and EDV of left ICA. The threshold values of Hcy with PSV of left CCA, EDV of left CCA, PSV of left ICA and EDV of left ICA were 14.00, 14.00, 14.00 and 13.50, respectively.Conclusion: These results indicate that a significant correlation exists between homocysteine at different concentrations and carotid artery hemodynamics.Keywords: Homocysteine, Hemodynamics, End diastolic velocity, Peak systolic velocit
    corecore