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D-optimal designs formulti-response linear mixed models
Linear mixed models have become popular in many statistical applications duringrecent years. However design issues for multi-response linear mixed models are rarelydiscussed. Themain purpose of this paper is to investigate D-optimal designs formultiresponselinear mixed models. We provide two equivalence theorems to characterizethe optimal designs for the estimation of the fixed effects and the prediction of randomeffects, respectively. Two examples of the D-optimal designs formulti-response linearmixed models are given for illustration
Fluctuations and Correlations of Conserved Charges in QCD at Finite Temperature with Effective Models
We study fluctuations of conserved charges including baryon number, electric
charge, and strangeness as well as the correlations among these conserved
charges in the 2+1 flavor Polyakov--Nambu--Jona-Lasinio model at finite
temperature. The calculated results are compared with those obtained from
recent lattice calculations performed with an improved staggered fermion action
at two values of the lattice cutoff with almost physical up and down quark
masses and a physical value for the strange quark mass. We find that our
calculated results are well consistent with those obtained in lattice
calculations except for some quantitative differences for fluctuations related
with strange quarks. Our calculations indicate that there is a pronounced cusp
in the ratio of the quartic to quadratic fluctuations of baryon number, i.e.
, at the critical temperature during the phase
transition, which confirms that is a useful probe
of the deconfinement and chiral phase transition.Comment: 24 pages, 11 figures; final version published in Phys. Rev.
Constraining Sub-Parsec Binary Supermassive Black Holes in Quasars with Multi-Epoch Spectroscopy. II. The Population with Kinematically Offset Broad Balmer Emission Lines
A small fraction of quasars have long been known to show bulk velocity
offsets in the broad Balmer lines with respect to the systemic redshift of the
host galaxy. Models to explain these offsets usually invoke broad-line region
gas kinematics/asymmetry around single black holes (BHs), orbital motion of
massive (~sub-pc) binary black holes (BBHs), or recoil BHs, but single-epoch
spectra are unable to distinguish between these scenarios. The line-of-sight
(LOS) radial velocity (RV) shifts from long-term spectroscopic monitoring can
be used to test the BBH hypothesis. We have selected a sample of 399 quasars
with offset broad H-beta lines from the SDSS DR7 quasar catalog, and have
conducted second-epoch optical spectroscopy for 50 of them. Combined with the
existing SDSS spectra, the new observations enable us to constrain the LOS RV
shifts of broad H-beta lines with a rest-frame baseline of a few years to
nearly a decade. Using cross-correlation analysis, we detect significant (99%
confidence) radial accelerations in the broad H-beta lines in 24 of the 50
objects. We suggest that 9 of the 24 detections are sub-pc BBH candidates,
which show consistent velocity shifts independently measured from a second
broad line (either H-alpha or Mg II) without significant changes in the
broad-line profiles. Combining the results on the general quasar population
studied in Paper I, we find a tentative anti-correlation between the velocity
offset in the first-epoch spectrum and the average acceleration between two
epochs, which could be explained by orbital phase modulation when the time
separation between two epochs is a non-negligible fraction of the orbital
period of the motion causing the line displacement. We discuss the implications
of our results for the identification of sub-pc BBH candidates in offset-line
quasars and for the constraints on their frequency and orbital parameters.
[Abridged]Comment: 23 pages, 18 figures, ApJ in pres
Very Long Baseline Array Imaging of Type-2 Seyferts with Double-Peaked Narrow Emission Lines: Searches for Sub-kpc Dual AGNs and Jet-Powered Outflows
This paper presents Very Long Baseline Array (VLBA) observations of 13
double-peaked [O III] emission-line type-2 Active Galactic Nuclei (AGNs) at
redshifts 0.06 < z < 0.41 (with a median redshift of z~0.15) identified in the
Sloan Digital Sky Survey. Such double-peaked emission-line objects may result
from jets or outflows from the central engine or from a dual AGN. The VLBA
provides an angular resolution of <~10 pc at the distance of many of these
galaxies, sufficient to resolve the radio emission from extremely close dual
AGNs and to contribute to understanding the origin of double-peaked [O III]
emission lines. Of the 13 galaxies observed at 3.6 cm (8.4 GHz), we detect six
at a 1\sigma\ sensitivity level of ~0.15 mJy/beam, two of which show clear jet
structures on scales ranging from a few milliarcseconds to tens of
milliarcseconds (corresponding to a few pc to tens of pc at a median redshift
of 0.15). We suggest that radio-loud double-peaked emission-line type-2 AGNs
may be indicative of jet produced structures, but a larger sample of
double-peaked [O III] AGNs with high angular resolution radio observations will
be required to confirm this suggestion.Comment: 14 pages, 7 figures; ApJ in pres
A Smartphone-Based Prototype System for Incident/Work Zone Management Driven by Crowd-Sourced Data
This project develops a smartphone-based prototype system that supplements the 511 system to improve its dynamic traffic routing service to state highway users under non-recurrent congestion. This system will save considerable time to provide crucial traffic information and en-route assistance to travelers for them to avoid being trapped in traffic congestion due to accidents, work zones, hazards, or special events. It also creates a feedback loop between travelers and responsible agencies that enable the state to effectively collect, fuse, and analyze crowd-sourced data for next-gen transportation planning and management. This project can result in substantial economic savings (e.g. less traffic congestion, reduced fuel wastage and emissions) and safety benefits for the freight industry and society due to better dissemination of real-time traffic information by highway users. Such benefits will increase significantly in future with the expected increase in freight traffic on the network. The proposed system also has the flexibility to be integrated with various transportation management modules to assist state agencies to improve transportation services and daily operations
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