Results 281 to 290 of about 252,409 (330)

Full Vector Velocity Reconstruction Using Solar Orbiter Doppler Map Observations.

2022
The Solar Orbiter mission opens up opportunities forthe combined analysis of measurements obtained by solar imagers and spectrometers. For the first time, different space spectrometerswill be located at wide angles to each other, allowing three-dimensional (3D) spectroscopy of the solar atmosphere.The aim of this work is to prepare the methodology to ...
Podladchikova, Olena, Harra, Louise, Barczynski, Krzysztof, Mandrini, Cristina, Auchere, F., Berghmans, David, Buchlin, Eric, Dolla, Laurent, Mierla, Marilena, Parenti, Susanna, Rodriguez, Luciano   +10 more
openaire   +1 more source

Inter- and intra-observer variability of Doppler peak velocity measurements: An in-vitro study

Ultrasound in Medicine & Biology, 1990
To determine the variability of pulsed Doppler peak velocity measurements, four radiologists with differing experience were tested using a calibrated flow phantom. Two ultrasound units, three probes and eight velocity rates varying between 40.5 and 78 cm/sec were studied, with a total of 303 measurements.
F N, Tessler, C, Kimme-Smith, M L, Sutherland, V L, Schiller, R R, Perrella, E G, Grant   +5 more
openaire   +2 more sources

Evaluation of soft-tissue masses using segmented color Doppler velocity images: preliminary observations.

American Journal of Roentgenology, 1999
We report our initial experience with segmented color Doppler velocity-based estimates of tumor vascularity for various histogically proven soft-tissue masses.Color Doppler sonography of 23 histologically proven masses in 22 patients was performed. Digital color Doppler images were acquired directly off the scanner output or from video recordings and ...
R S, Adler, D S, Bell, J C, Bamber, E, Moskovic, J M, Thomas   +4 more
openaire   +2 more sources

Estimating vertical velocity and radial flow from Doppler radar observations of tropical cyclones

Quarterly Journal of the Royal Meteorological Society, 2006
AbstractThe mesoscale vorticity method (MVM) is used in conjunction with the ground‐based velocity track display (GBVTD) to derive the inner‐core vertical velocity from Doppler radar observations of tropical cyclone (TC) Danny (1997). MVM derives the vertical velocity from vorticity variations in space and in time based on the mesoscale vorticity ...
J. L. Lee, W. C. Lee, A. E. Macdonald
openaire   +1 more source

The orientation of the solar rotation axis from Doppler velocity observations

Solar Physics, 1981
Mt. Wilson observations of solar velocity fields have been examined for evidence that the rotation axis of the nonmagnetic gas at the solar surface is oriented differently that the axis found by Carrington (1863) from sunspot observations. No difference is found with accuracy of 0.15 in the angle of inclination of the axis to the ecliptic.
openaire   +1 more source

Observer's Position and Velocity Determination Using Satellite Doppler Measurements

1968
Abstract : Existing navigation techniques using satellite doppler shift measurements are sensitive to observer velocity errors. A model is developed for determining the position and velocity of the observer with the result that the navigation process will be independent of external velocity source error.
openaire   +1 more source

STARE and EISCAT measurements: Evidence for the limitation of STARE Doppler velocity observations by the ion acoustic velocity

Journal of Geophysical Research: Space Physics, 1990
Measurements of the phase velocity of ionospheric plasma waves using the STARE radar system are compared with the electron drift velocity and the ion acoustic velocity calculated from data measured by EISCAT. This comparison shows that for those flow angles that are smaller than the largest flow angle (θs) for which the component of the electron drift ...
W. Kofman, E. Nielsen
openaire   +1 more source

Localization of a Moving Object With Sensors in Motion by Time Delays and Doppler Shifts

IEEE Transactions on Signal Processing, 2020
This paper investigates the problem of active localization of a moving object in its initial position and velocity, using time delay only or with Doppler shift measurements acquired by a number of monostatic sensors. Each sensor has non-negligible motion
Tianyi Jia, Dominic K. C. Ho, Haiyan Wang, Xiaohong Shen   +3 more
semanticscholar   +1 more source

Intra‐observer and inter‐observer reliability of the pulsatility index calculated from pulsed Doppler flow velocity waveforms in three fetal vessels

BJOG: An International Journal of Obstetrics & Gynaecology, 1993
ABSTRACTObjective Study of the intra observer and inter observer reliability of the pulsatility index, calculated from pulsed Doppler recordings of three fetal vessels.Design Flow velocity waveforms (FVW) were recorded from the umbilical artery, the fetal descending aorta and the fetal internal carotid artery. Intra‐observer reliability was
Scherjon, S. A., Kok, J. H., Oosting, H., Zondervan, H. A.   +3 more
openaire   +3 more sources

Actualization Analysis of LEO Opportunistic Doppler Aided GNSS Precise Point Positioning Using Moving Horizon Estimation

IEEE Transactions on Vehicular Technology
As the promising advantages, which are spectral and geometric diversity as well as the fast orbital velocity and high received signal power, the signal of opportunity (SoOP) of low-earth-orbit (LEO) satellite is used to assist the Global Navigation ...
Peng Liu, K. Ling, Honglei Qin, Muyuan Jiang, Jun Lu   +4 more
semanticscholar   +1 more source