Reduced complexity on-line estimation of hidden Markov model parameters

In this paper we propose and study low complexity algorithms for on-line estimation of hidden Markov model (HMM) parameters. The estimates approach the true model parameters as the measurement noise approaches zero, but otherwise give improved estimates, albeit with bias. On a nite data set in the high noise case, the bias may not be signi cantly more severe than for a higher complexity asymptotically optimal scheme. Our algorithms require O(N3) calculations per time instant, where N is the number of states. Previous algorithms based on earlier hidden Markov model signal processing methods, including the expectation-maximumisation (EM) algorithm require O(N4) calculations per time instant

The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances

We report data for $I$ band Surface Brightness Fluctuation (SBF) magnitudes, V-I colors, and distance moduli for 300 galaxies. The Survey contains E, S0 and early-type spiral galaxies in the proportions of 49:42:9, and is essentially complete for E galaxies to Hubble velocities of 2000 km/s, with a substantial sampling of E galaxies out to 4000 km/s. The median error in distance modulus is 0.22 mag. We also present two new results from the Survey. (1) We compare the mean peculiar flow velocity (bulk flow) implied by our distances with predictions of typical cold dark matter transfer functions as a function of scale, and find very good agreement with cold, dark matter cosmologies if the transfer function scale parameter $\Gamma$, and the power spectrum normalization $\sigma_8$ are related by $\sigma_8 \Gamma^{-0.5} \approx 2\pm0.5$. Derived directly from velocities, this result is independent of the distribution of galaxies or models for biasing. The modest bulk flow contradicts reports of large-scale, large-amplitude flows in the $\sim200$ Mpc diameter volume surrounding our Survey volume. (2) We present a distance-independent measure of absolute galaxy luminosity, \Nbar, and show how it correlates with galaxy properties such as color and velocity dispersion, demonstrating its utility for measuring galaxy distances through large and unknown extinction.Comment: Accepted for publication in ApJ (10 January 2001); 23 page

Determining the galactic mass distribution using tidal streams from globular clusters

We discuss how to use tidal streams from globular clusters to measure the mass distribution of the Milky Way. Recent proper motion determinations for globular clusters from plate measurements and Hipparcos astrometry provide several good candidates for Galactic mass determinations in the intermediate halo, far above the Galactic disk, including Pal 5, NGC 4147, NGC 5024 (M53) and NGC 5466; the remaining Hipparcos clusters provide candidates for measurements several kpc above and below the disk. These clusters will help determine the profile and shape of the inner halo. To aid this effort, we present two methods of mass determination: one, a generalization of rotation-curve mass measurements, which gives the mass and potential from complete position-velocity observations for stream stars; and another using a simple chi^2 estimator, which can be used when only projected positions and radial velocities are known for stream stars. We illustrate the use of the latter method using simulated tidal streams from Pal 5 and find that fairly accurate mass determinations are possible even for relatively poor data sets. Follow-up observations of clusters with proper motion determinations may reveal tidal streams; obtaining radial velocity measurements would enable accurate measurements of the mass distribution in the inner Galaxy.Comment: 21 pages, 6 figures, published in A

Candidate molecular ions for an electron electric dipole moment experiment

This paper is a theoretical work in support of a newly proposed experiment (R. Stutz and E. Cornell, Bull. Am. Soc. Phys. 89, 76 2004) that promises greater sensitivity to measurements of the electron's electric dipole moment (EDM) based on the trapping of molecular ions. Such an experiment requires the choice of a suitable molecule that is both experimentally feasible and possesses an expectation of a reasonable EDM signal. We find that the molecular ions PtH+, HfH+, and HfF+ are suitable candidates in their low-lying triplet Delta states. In particular, we anticipate that the effective electric fields generated inside these molecules are approximately of 73 GV/cm, -17 GV/cm, and -18 GV/cm respectively. As a byproduct of this discussion, we also explain how to make estimates of the size of the effective electric field acting in a molecule, using commercially available, nonrelativistic molecular structure software.Comment: 25 pages, 3 figures, submitted to Physical Review

Note and Comment

The International Law Association and Its Last Meeting; The Extent to Which the Action of Medical Boards may be Controlled By Mandamus; The Effect Upon An Illegal marriage of Cohabitiation After the Removal of the Impediment

Differences in Mathematics and Science Achievement by Grade 5 and Grade 8 Student Economic Status: A Multiyear, Statewide Study

Differences present in average raw scores of Grade 5 and Grade 8 students on the State of Texas Assessment of Academic Readiness STAAR Mathematics and Science exams were analyzed with regard to student economic status Test results were examined for four school years i e 2011- 2012 through 2014-2015 Statistically significant results were present for all STAAR Mathematics and Science exams for each year and each grade analyzed Represented in the analysis were moderate effect sizes Cohen s d each year of the study for the Grade 5 STAAR Mathematics scores Grade 5 STAAR Science scores Grade 8 STAAR Science scores and the 2014-2015 Grade 8 exams STAAR Mathematics scores However the differences in the Grade 8 STAAR Mathematics scores represented a small effect size for the 2011-2012 through the 2013-2014 year