Estimation from quantized Gaussian measurements: when and how to use dither

Subtractive dither is a powerful method for removing the signal dependence of quantization noise for coarsely quantized signals. However, estimation from dithered measurements often naively applies the sample mean or midrange, even when the total noise is not well described with a Gaussian or uniform distribution. We show that the generalized Gaussian distribution approximately describes subtractively dithered, quantized samples of a Gaussian signal. Furthermore, a generalized Gaussian fit leads to simple estimators based on order statistics that match the performance of more complicated maximum likelihood estimators requiring iterative solvers. The order statistics-based estimators outperform both the sample mean and midrange for nontrivial sums of Gaussian and uniform noise. Additional analysis of the generalized Gaussian approximation yields rules of thumb for determining when and how to apply dither to quantized measurements. Specifically, we find subtractive dither to be beneficial when the ratio between the Gaussian standard deviation and quantization interval length is roughly less than one-third. When that ratio is also greater than 0.822/K^0.930 for the number of measurements K > 20, estimators we present are more efficient than the midrange.https://arxiv.org/abs/1811.06856Accepted manuscrip

Medium Modifications of the Rho Meson at CERN/SPS Energies

Rho meson propagation in hot hadronic matter is studied in a model with coupling to $\pi\pi$ states. Medium modifications are induced by a change of the pion dispersion relation through collisions with nucleons and $\Delta's$ in the fireball. Maintaining gauge invariance dilepton production is calculated and compared to the recent data of the CERES collaboration in central S+Au collisions at 200 GeV/u. The observed enhancement of the rate below the rho meson mass can be largely accounted for.Comment: 10 pages RevTeX and 2 figures (uuencoded .ps-files

Photon production in relativistic nuclear collisions at SPS and RHIC energies

Chiral Lagrangians are used to compute the production rate of photons from the hadronic phase of relativistic nuclear collisions. Special attention is paid to the role of the pseudovector a_1 meson. Calculations that include reactions with strange mesons, hadronic form factors and vector spectral densities consistent with dilepton production, as well as the emission from a quark-gluon plasma and primordial nucleon-nucleon collisions, reproduce the photon spectra measured at the Super Proton Synchrotron (SPS). Predictions for the Relativistic Heavy Ion Collider (RHIC) are made.Comment: Work presented at the 26th annual Montreal-Rochester-Syracuse-Toronto conference (MRST 2004) on high energy physics, Montreal, QC, Canada, 12-14 May 2004. 8 pages, 3 figure

Calibration of weirs by means of critical flow and specific energy

For many years man has been relying more each day upon metering devices to measure the flow of fluids in industry. The orifice, orifice meter, venturi meter, pitot tube, nozzle, flume and the weir have been employed, each having its own particular advantage. In this parade of metering progress, the contracted weir has long been the forgotten brother of the suppressed weir. In almost every textbook on hydraulics or fluid mechanics, the following words appear, end contractions are to be avoided where the weir cannot be calibrated . This skepticism and the length or absurdity of some contracted weir formulas led to the development of this study --Introduction, page 1

A History of the Pacific Northwest District Conference of the Evangelical Free Church of America

The Evangelical Free Church of America is a merger. It should be noted that the Free Church groups that merged in 1950 to form the Evangelical Free Church of America, each had early beginnings in the Northwest. The first Free Evangelical witness in the Pacific Northwest occurred in the decade of the 1880s, following the historic meetings of organization at Boone, Iowa, and Boston, Massachusetts in 1884. The first churches of both the Swedish and Norwegian-Danish groups were centered in the Seattle-Tacoma area. Progress and growth were impeded in those early days by language and distance barriers. By the time that the language change was nearly completed in the year 1935, the Swedish group had three organized congregations and the Norwegian-Danish. group had four. By the time of the merger in 1950, both groups had grown appreciably. The Swedish group had added nine churches, the Norwegian-Danish group eight

A chiral crystal in cold QCD matter at intermediate densities?

The analogue of Overhauser (particle-hole) pairing in electronic systems (spin-density waves with non-zero total momentum $Q$) is analyzed in finite-density QCD for 3 colors and 2 flavors, and compared to the color-superconducting BCS ground state (particle-particle pairing, $Q$=0). The calculations are based on effective nonperturbative four-fermion interactions acting in both the scalar diquark as well as the scalar-isoscalar quark-hole ('$\sigma$') channel. Within the Nambu-Gorkov formalism we set up the coupled channel problem including multiple chiral density wave formation, and evaluate the resulting gaps and free energies. Employing medium-modified instanton-induced 't Hooft interactions, as applicable around $\mu_q\simeq 0.4$ GeV (or 4 times nuclear saturation density), we find the 'chiral crystal phase' to be competitive with the color superconductor.Comment: 14 pages ReVTeX, including 11 ps-/eps-figure