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Macaulay, E,Nichol, R C,Bacon, D,Brout, D,Davis, T M,Zhang, B,Bassett, B A,Scolnic, D,Mö,ller, A,D’Andrea, C B,Hinton, S R,Kessler, R,Kim, A G,Lasker, J,Lidman, C,Sako, M,Smith, M,Sullivan, M,Abbo Oxford University Press 2019 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.486 No.2
<B>ABSTRACT</B><P>We present an improved measurement of the Hubble constant (H0) using the ‘inverse distance ladder’ method, which adds the information from 207 Type Ia supernovae (SNe Ia) from the Dark Energy Survey (DES) at redshift 0.018 < z < 0.85 to existing distance measurements of 122 low-redshift (z < 0.07) SNe Ia (Low-z) and measurements of Baryon Acoustic Oscillations (BAOs). Whereas traditional measurements of H0 with SNe Ia use a distance ladder of parallax and Cepheid variable stars, the inverse distance ladder relies on absolute distance measurements from the BAOs to calibrate the intrinsic magnitude of the SNe Ia. We find H0 = 67.8 ± 1.3 km s−1 Mpc−1 (statistical and systematic uncertainties, 68 per cent confidence). Our measurement makes minimal assumptions about the underlying cosmological model, and our analysis was blinded to reduce confirmation bias. We examine possible systematic uncertainties and all are below the statistical uncertainties. Our H0 value is consistent with estimates derived from the Cosmic Microwave Background assuming a ΛCDM universe.</P>
IN-CYLINDER FLOW ANALYSIS USING WAVELET ANALYSIS
D. PARK,P. E. SULLIVAN,J. S. WALLACE 한국자동차공학회 2006 International journal of automotive technology Vol.7 No.3
Better fundamental understanding of the interactions between the in-cylinder flows and combustion process is an important requirement for further improvement in the fuel economy and emissions of internal combustion (IC) engines. Flow near a spark plug at the time of ignition plays an important role for early flame kernel development (EFKD). Velocity data measurements in this study were made with a two-component laser Doppler velocimetry (LDV) near a spark plug in a single cylinder optical spark ignition (SI) engine with a heart-shaped combustion chamber. LDV velocity data were collected on an individual cycle basis under wide-open motored conditions with an engine speed of 1,000 rpm. This study examines and compares the flow fields as interpreted through ensemble, cyclic and discrete wavelet transformation(DWT) analysis. The energy distributions in the non-stationary engine flows are also investigated over crank angle phase and frequency through continuous wavelet transformation (CWT) for a position near a spark plug. Wavelet analysis is appropriate for analyzing the flow fields in engines because it gives information about the transient events in a time and frequency plane. The results of CWT analysis are provided and compared with the mean flows of DWT first decomposition level for all cycles at a position. Low frequency high energy found with CWT corresponds well with the peak locations of the mean velocity. The high frequency flows caused by the intake jet gradually decay as the piston approaches the bottom dead center (BDC).
Lee, D.H.,Nam, U.W.,Kim, G.H.,Pak, S.,Zemcov, M.,Bock, J.J.,Battle, J.,Sullivan, I.,Mason, P.,Tsumura, K.,Matsumoto, T.,Matsuura, S.,Renbarger, T.,Keating, B. 한국천문학회 2007 天文學論叢 Vol.22 No.4
The international cooperation project CIBER (Cosmic Infrared Background ExpeRiment) is a rocket-borne instrument, of which the scientific goal is to measure the cosmic near-infrared extra-galactic background to search for signatures of primordial galaxy formation. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. Currently, all the subsystems have been built, and the integration, testing, and calibration of the CIBER system are on process for the scheduled launch in June 2008.