Minimizing error sources in gauge block mechanical comparison measurements

1998 ◽  
Author(s):  
Bryon S. Faust ◽  
John R. Stoup ◽  
Eric S. Stanfield
Keyword(s):  
Error Sources ◽  
Gauge Block ◽  
Comparison Measurements

scholarly journals Finding minimum type error sources

2014 ◽  
Vol 49 (10) ◽  
pp. 525-542 ◽  
Author(s):  
Zvonimir Pavlinovic ◽  
Tim King ◽  
Thomas Wies
Keyword(s):  
Error Sources

scholarly journals A Second-Order Time-Difference Position Constrained Reduced-Dynamic Technique for the Precise Orbit Determination of LEOs Using GPS

2021 ◽  
Vol 13 (15) ◽  
pp. 3033
Author(s):  
Hui Wei ◽  
Jiancheng Li ◽  
Xinyu Xu ◽  
Shoujian Zhang ◽  
Kaifa Kuang
Keyword(s):  
Orbit Determination ◽  
Dynamic Models ◽  
Precise Orbit Determination ◽  
Second Order ◽  
Time Difference ◽  
Error Sources ◽  
Precise Orbit ◽  
Unmodeled Dynamic ◽  
Reduced Dynamic

In this paper, we propose a new reduced-dynamic (RD) method by introducing the second-order time-difference position (STP) as additional pseudo-observations (named the RD_STP method) for the precise orbit determination (POD) of low Earth orbiters (LEOs) from GPS observations. Theoretical and numerical analyses show that the accuracies of integrating the STPs of LEOs at 30 s intervals are better than 0.01 m when the forces (<10−5 ms−2) acting on the LEOs are ignored. Therefore, only using the Earth’s gravity model is good enough for the proposed RD_STP method. All unmodeled dynamic models (e.g., luni-solar gravitation, tide forces) are treated as the error sources of the STP pseudo-observation. In addition, there are no pseudo-stochastic orbit parameters to be estimated in the RD_STP method. Finally, we use the RD_STP method to process 15 days of GPS data from the GOCE mission. The results show that the accuracy of the RD_STP solution is more accurate and smoother than the kinematic solution in nearly polar and equatorial regions, and consistent with the RD solution. The 3D RMS of the differences between the RD_STP and RD solutions is 1.93 cm for 1 s sampling. This indicates that the proposed method has a performance comparable to the RD method, and could be an alternative for the POD of LEOs.

scholarly journals Bilingual advantage in early EFL pronunciation accuracy of German 4th-graders

2021 ◽  
pp. 136700692199681
Author(s):  
Teresa Kieseier
Keyword(s):  
Foreign Language ◽  
Primary Schools ◽  
Social Background ◽  
Target Language ◽  
Error Sources ◽  
Common Error ◽  
Language Background ◽  
Background Factors ◽  
Language Groups ◽  
Error Types

Aims and Objectives: We compared speech accuracy and pronunciation patterns between early learners of English as a foreign language (EFL) with different language backgrounds. We asked (1) whether linguistic background predicts pronunciation outcomes, and (2) if error sources and substitution patterns differ between monolinguals and heterogeneous bilinguals. Methodology: Monolingual and bilingual 4th-graders ( N = 183) at German public primary schools participated in an English picture-naming task. We further collected linguistic, cognitive and social background measures to control for individual differences. Data and Analysis: Productions were transcribed and rated for accuracy and error types by three independent raters. We compared monolingual and bilingual pronunciation accuracy in a linear mixed-effects regression analysis controlling for background factors at the individual and institutional level. We further categorized all error types and compared their relative frequency as well as substitution patterns between different language groups. Findings: After background factors were controlled for, bilinguals (irrespective of specific L1) significantly outperformed their monolingual peers on overall pronunciation accuracy. Irrespective of language background, the most frequent error sources overlapped, affecting English sounds which are considered marked, are absent from the German phoneme inventory, or differ phonetically from a German equivalent. Originality: This study extends previous work on bilingual advantages in other domains of EFL to less researched phonological skills. It focuses on overall productive skills in young FL learners with limited proficiency and provides an overview over the most common error sources and substitution patterns in connection to language background. Significance/Implications: The study highlights that bilingual learners may deploy additional resources in the acquisition of target language phonology that should be addressed in the foreign language classroom.

scholarly journals Effects of Simulated Error-Sources on Different 3-D CSI-EPT Strategies

2021 ◽  
pp. 1-1
Author(s):  
Reijer Leijsen ◽  
Wyger M Brink ◽  
Andrew G Webb ◽  
Rob Remis
Keyword(s):  
Error Sources

scholarly journals Characterization of error sources in an inertial unit using Allan variance and nonlinear parameter adjustment

2020 ◽  
Vol 1674 ◽  
pp. 012004
Author(s):  
W A Hernandez ◽  
J S Castillo-Corredor ◽  
J A Ramos-Cifuentes ◽  
F Fuentes ◽  
L F Castañeda
Keyword(s):  
Allan Variance ◽  
Nonlinear Parameter ◽  
Error Sources ◽  
Parameter Adjustment ◽  
Inertial Unit

Molar Absorptivity Values for Aflatoxins and Justification for Their Use as Criteria of Purity of Analytical Standards

1970 ◽  
Vol 53 (1) ◽  
pp. 96-101 ◽  
Author(s):  
J V Rodricks ◽  
L Stoloff ◽  
W A Pons ◽  
J A Robertson ◽  
L A Goldblatt
Keyword(s):  
Thin Layer ◽  
Statistical Study ◽  
Molar Absorptivity ◽  
Confidence Limits ◽  
Components Of Variance ◽  
Significant Difference ◽  
Single Determination ◽  
Comparison Measurements ◽  
Analytical Standards

Abstract Measurements of molar absorptivities in methanol were carried out by two laboratories on samples of anatoxins Bi and Gi prepared and purified independently in four laboratories and on samples of aflatoxins B2 and G2 prepared and purified independently in three laboratories. Molar absorptivities of pure aflatoxins Bi, B2, G1, and G2 in benzene-acetonitrile (98 + 2) were determined at two laboratories. With the exception of aflatoxin G2, no significant difference between aflatoxin samples could be demonstrated. Molar absorptivity values and absorbance ratios for each aflatoxin, based on these data, are given. Statistical 95% confidence limits were established for a single determination of molar absorptivity. A statistical study was made of the components of variance which contribute to the accuracy of the determination of molar absorptivity. A comparison of the fluorescence intensities of spots of various aflatoxin preparations, developed on silica gel-coated thin layer plates, with the amount of aflatoxin in each spotting solution as determined by absorbance measurements, demonstrated the validity of using absorbance and fluorescence comparison measurements for aflatoxin quantitation.

scholarly journals Tropospheric NO<sub>2</sub> column densities deduced from zenith-sky DOAS measurements in Shanghai, China, and their application to satellite validation

2009 ◽  
Vol 9 (11) ◽  
pp. 3641-3662 ◽  
Author(s):  
D. Chen ◽  
B. Zhou ◽  
S. Beirle ◽  
L. M. Chen ◽  
T. Wagner
Keyword(s):  
Satellite Data ◽  
Urban Site ◽  
Optical Absorption Spectroscopy ◽  
Vertical Column ◽  
Error Sources ◽  
Satellite Validation ◽  
Tropospheric No2 ◽  
Realistic Information ◽  
Good Agreement

Abstract. Zenith-sky scattered sunlight observations using differential optical absorption spectroscopy (DOAS) technique were carried out in Shanghai, China (31.3° N, 121.5° E) since December 2006. At this polluted urban site, the measurements provided NO2 total columns in the daytime. Here, we present a new method to extract time series of tropospheric vertical column densities (VCDs) of NO2 from these observations. The derived tropospheric NO2 VCDs are important quantities for the estimation of emissions and for the validation of satellite observations. Our method makes use of assumptions on the relative NO2 height profiles and the diurnal variation of stratospheric NO2 VCDs. The main error sources arise from the uncertainties in the estimated stratospheric slant column densities (SCDs) and the determination of tropospheric NO2 air mass factor (AMF). For a polluted site like Shanghai, the accuracy of our method is conservatively estimated to be <25% for solar zenith angle (SZA) lower than 70°. From simultaneously performed long-path DOAS measurements, the NO2 surface concentrations at the same site were observed and the corresponding tropospheric NO2 VCDs were estimated using the assumed seasonal NO2 profiles in the planetary boundary layer (PBL). By making a comparison between the tropospheric NO2 VCDs from zenith-sky and long-path DOAS measurements, it is found that the former provides more realistic information about total tropospheric pollution than the latter, so it's more suitable for satellite data validation. A comparison between the tropospheric NO2 VCDs from ground-based zenith-sky measurements and SCIAMACHY was also made. Satellite validation for a strongly polluted area is highly needed, but exhibits also a great challenge. Our comparison shows good agreement, considering in particular the different spatial resolutions between the two measurements. Remaining systematic deviations are most probably related to the uncertainties of satellite data caused by the assumptions on aerosol properties as well as the layer heights of aerosols and NO2.

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