scholarly journals Geometrical information on the solar shape: high precision results with SDO/HMI

2012 ◽  
Vol 8 (S294) ◽  
pp. 483-484
Author(s):  
Xiaofan Wang ◽  
Costantino Sigismondi
Keyword(s):  
High Precision ◽  
Plane Deformation ◽  
Signal Amplitude ◽  
Solar Diameter ◽  
Solar Oblateness ◽  
Scale Calibration ◽  
Geometrical Information ◽  
Focus Plane ◽  
Pixel Scale ◽  
Very High

AbstractThe uncertainty of measurement of solar diameter is depending on the observational time scale. Full-disc images of SDO/HMI and the images from ground observations in Huairou Solar Observing Station have been analyzed to get the values of solar diameter. The satellite observations reach a very high precision, but the absolute image scale still need to be calibrated. The solar oblateness is a more challenging measurement than the diameter, since the signal amplitude is a few milli-arcseconds. It is a relative measurement, then not affected by the pixel scale calibration required by the diameter measurement. But the results are strongly dependent on the state of instrument such as focus plane deformation and on the calculation process.

scholarly journals Separate Universe calibration of the dependence of halo bias on cosmic web anisotropy

2020 ◽  
Vol 499 (3) ◽  
pp. 4418-4431 ◽  
Author(s):  
Sujatha Ramakrishnan ◽  
Aseem Paranjape
Keyword(s):  
Dark Matter ◽  
High Precision ◽  
Gaussian Distribution ◽  
Initial Perturbation ◽  
Analytical Framework ◽  
Web Environment ◽  
Wide Range ◽  
Galaxy Assembly ◽  
Very High ◽  
Good Agreement

ABSTRACT We use the Separate Universe technique to calibrate the dependence of linear and quadratic halo bias b1 and b2 on the local cosmic web environment of dark matter haloes. We do this by measuring the response of halo abundances at fixed mass and cosmic web tidal anisotropy α to an infinite wavelength initial perturbation. We augment our measurements with an analytical framework developed in earlier work that exploits the near-lognormal shape of the distribution of α and results in very high precision calibrations. We present convenient fitting functions for the dependence of b1 and b2 on α over a wide range of halo mass for redshifts 0 ≤ z ≤ 1. Our calibration of b2(α) is the first demonstration to date of the dependence of non-linear bias on the local web environment. Motivated by previous results that showed that α is the primary indicator of halo assembly bias for a number of halo properties beyond halo mass, we then extend our analytical framework to accommodate the dependence of b1 and b2 on any such secondary property that has, or can be monotonically transformed to have, a Gaussian distribution. We demonstrate this technique for the specific case of halo concentration, finding good agreement with previous results. Our calibrations will be useful for a variety of halo model analyses focusing on galaxy assembly bias, as well as analytical forecasts of the potential for using α as a segregating variable in multitracer analyses.

scholarly journals Equipartition principle for Wigner matrices

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhigang Bao ◽  
László Erdős ◽  
Kevin Schnelli
Keyword(s):  
High Precision ◽  
Quantum Systems ◽  
Wigner Matrices ◽  
Very High

Abstract We prove that the energy of any eigenvector of a sum of several independent large Wigner matrices is equally distributed among these matrices with very high precision. This shows a particularly strong microcanonical form of the equipartition principle for quantum systems whose components are modelled by Wigner matrices.

Formation flying for very high precision astrometry: NEAT and micro-NEAT mission concepts

2014 ◽  
Vol 2 (1) ◽  
pp. 3 ◽  
Author(s):  
Fabien Malbet ◽  
Alexis Brandeker ◽  
Alain Léger ◽  
Bjorn Jakobsson ◽  
Renaud Goullioud ◽  
...  
Keyword(s):  
High Precision ◽  
Formation Flying ◽  
Very High ◽  
Precision Astrometry

A HIGHLY ACCURATE BOOTSTRAPPING ALGORITHM FOR WORD SENSE DISAMBIGUATION

2001 ◽  
Vol 10 (01n02) ◽  
pp. 5-21 ◽  
Author(s):  
RADA F. MIHALCEA ◽  
DAN I. MOLDOVAN
Keyword(s):  
High Precision ◽  
Word Sense Disambiguation ◽  
Original Text ◽  
Word Sense ◽  
New Words ◽  
Input Text ◽  
Ambiguous Words ◽  
Sense Disambiguation ◽  
Very High

In this paper, we present a bootstrapping algorithm for Word Sense Disambiguation which succeeds in disambiguating a subset of the words in the input text with very high precision. It uses WordNet and a semantic tagged corpus, for the purpose of identifying the correct sense of the words in a given text. The bootstrapping process initializes a set of ambiguous words with all the nouns and verbs in the text. It then applies various disambiguation procedures and builds a set of disambiguated words: new words are sense tagged based on their relation to the already disambiguated words, and then added to the set. This process allows us to identify, in the original text, a set of words which can be disambiguated with high precision; 55% of the verbs and nouns are disambiguated with an accuracy of 92%.

CANADIAN STANDARD OF FREQUENCY

1959 ◽  
Vol 37 (1) ◽  
pp. 10-18 ◽  
Author(s):  
S. N. Kalra ◽  
C. F. Pattenson ◽  
M. M. Thomson
Keyword(s):  
High Precision ◽  
Phase Measurement ◽  
Frequency Standard ◽  
Frequency Stability ◽  
Absolute Frequency ◽  
Standard Frequency ◽  
Astronomical Observations ◽  
The Past ◽  
Time Signals ◽  
Very High

Over the past 3 years a frequency standard of very high precision has been installed in Canada. It is composed of equipment located in three different laboratories in Ottawa, Ontario, but separated by a few miles. Intercomparison of frequency between these laboratories, which is done by sending signals over telephone lines and related techniques, is briefly described. Results indicate frequency stability of about 2:1010 over short and long periods. Absolute frequency is determined from astronomical observations. International inter-comparison is carried out by phase measurement of standard frequency and by observations of time signals; some of the results are presented.

scholarly journals The surface albedo of the Greenland ice sheet: satellite-derived and in situ measurements in the Søndre Strømfjord area during the 1991 melt season

1996 ◽  
Vol 42 (141) ◽  
pp. 364-374 ◽  
Author(s):  
Wouter H. Knap ◽  
Johannes Oerlemans
Keyword(s):  
Surface Albedo ◽  
Near Infrared ◽  
Broad Band ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Zone Ii ◽  
High Degree ◽  
Pixel Scale ◽  
Very High

AbstractThe temporal and spatial variation in the surface albedo of the Greenland ice sheet during the ablation season of 1991 is investigated. The study focuses on an area east of Søndre Strømfjord measuring 200 km by 200 km and centred at 67°5′ N, 48° 13′W. The analysis is based on satellite radiance measurements carried out by the Advanced Very High Resolution Radiometer (AVHRR). The broad-band albedo is estimated from the albedos in channel 1 (visible) and channel 2 (near-infrared). The results are calibrated with the surface albedo of sea and dry snow.Satellite-derived albedos are compared with GIMEX ground measurements at three stations. There is a high degree of consistency in temporal variation at two of the three stations. Large systematic differences are attributed to albedo variations on sub-pixel scale.In the course of the ablation season four zones appear, each parallel to the ice edge. It is proposed that these are, in order of increasing altitude: (I) clean and dry ice, (II) ice with surface water, (III) superimposed ice, and (IV) snow. An extensive description of these zones is given on the basis of the situation on 25 July 1991. Zones I, III and IV reveal fairly constant albedos (0.46, 0.65 and 0.75 on average), whereas zone II is characterised by an albedo minimum (0.34). Survey of the western margin of the Greenland ice sheet (up to 71° N) shows that the zonation occurs between 66° and 70° N.

Fast Quantitative 1H–13C Two-Dimensional NMR with Very High Precision

2013 ◽  
Vol 85 (9) ◽  
pp. 4777-4783 ◽  
Author(s):  
Estelle Martineau ◽  
Serge Akoka ◽  
Renaud Boisseau ◽  
Benoît Delanoue ◽  
Patrick Giraudeau
Keyword(s):  
High Precision ◽  
Two Dimensional ◽  
Very High

scholarly journals The surface albedo of the Greenland ice sheet: satellite-derived and in situ measurements in the Søndre Strømfjord area during the 1991 melt season

1996 ◽  
Vol 42 (141) ◽  
pp. 364-374 ◽  
Author(s):  
Wouter H. Knap ◽  
Johannes Oerlemans
Keyword(s):  
Surface Albedo ◽  
Near Infrared ◽  
Broad Band ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Zone Ii ◽  
High Degree ◽  
Pixel Scale ◽  
Very High

AbstractThe temporal and spatial variation in the surface albedo of the Greenland ice sheet during the ablation season of 1991 is investigated. The study focuses on an area east of Søndre Strømfjord measuring 200 km by 200 km and centred at 67°5′ N, 48° 13′W. The analysis is based on satellite radiance measurements carried out by the Advanced Very High Resolution Radiometer (AVHRR). The broad-band albedo is estimated from the albedos in channel 1 (visible) and channel 2 (near-infrared). The results are calibrated with the surface albedo of sea and dry snow.Satellite-derived albedos are compared with GIMEX ground measurements at three stations. There is a high degree of consistency in temporal variation at two of the three stations. Large systematic differences are attributed to albedo variations on sub-pixel scale.In the course of the ablation season four zones appear, each parallel to the ice edge. It is proposed that these are, in order of increasing altitude: (I) clean and dry ice, (II) ice with surface water, (III) superimposed ice, and (IV) snow. An extensive description of these zones is given on the basis of the situation on 25 July 1991. Zones I, III and IV reveal fairly constant albedos (0.46, 0.65 and 0.75 on average), whereas zone II is characterised by an albedo minimum (0.34). Survey of the western margin of the Greenland ice sheet (up to 71° N) shows that the zonation occurs between 66° and 70° N.

scholarly journals Data Analysis and Calibration of Radiocarbon Dating Results from the Cemetery of the Marquises of Jin

Radiocarbon ◽  
2001 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Xiangyang Lu ◽  
Zhiyu Guo ◽  
Hongji Ma ◽  
Sixun Yuan ◽  
Xiaohong Wu
Keyword(s):  
Data Analysis ◽  
High Precision ◽  
Radiocarbon Dating ◽  
Careful Analysis ◽  
Historical Record ◽  
Calibration Result ◽  
Special Part ◽  
Peking University ◽  
Very High ◽  
Good Agreement

The chronology study of the cemetery of Marquises of Jin is valuable to improving the chronological table of Marquis of Jin family. It is also helpful for improving the chronological table of the Zhou Dynasty. The samples were measured at Peking University (PKUAMS). We also made an interlaboratory check with Isotrace to ensure the accuracy. By careful analysis of archaeological information, we built different models and calibrated by OxCal. The calibration results, both sampling contexts and estimations, are in very good agreement with the historical record. Because the dates of some events correspond to the special part of the curve, the calibration gets very high precision. The calibration result of tomb M93 suggests that its host is Marquis Shangshu instead of Marquis Wen.

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