Local calibration of MEPDG rut models: Oklahoma’s experience from an instrumented pavement section

2014 ◽  
pp. 135-140
Author(s):  
Nur Hossain ◽  
Dharamveer Singh ◽  
Musharraf Zaman ◽  
SM Rassel
Keyword(s):  
Local Calibration

scholarly journals Cobot User Frame Calibration: Evaluation and Comparison between Positioning Repeatability Performances Achieved by Traditional and Vision-Based Methods

Robotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 45
Author(s):  
Roberto Pagani ◽  
Cristina Nuzzi ◽  
Marco Ghidelli ◽  
Alberto Borboni ◽  
Matteo Lancini ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Production Line ◽  
Calibration Method ◽  
Fiducial Marker ◽  
Positioning System ◽  
Local Calibration ◽  
Calibration Methods ◽  
Robot Positioning ◽  
Good Repeatability ◽  
Calibration Time

Since cobots are designed to be flexible, they are frequently repositioned to change the production line according to the needs; hence, their working area (user frame) needs to be often calibrated. Therefore, it is important to adopt a fast and intuitive user frame calibration method that allows even non-expert users to perform the procedure effectively, reducing the possible mistakes that may arise in such contexts. The aim of this work was to quantitatively assess the performance of different user frame calibration procedures in terms of accuracy, complexity, and calibration time, to allow a reliable choice of which calibration method to adopt and the number of calibration points to use, given the requirements of the specific application. This has been done by first analyzing the performances of a Rethink Robotics Sawyer robot built-in user frame calibration method (Robot Positioning System, RPS) based on the analysis of a fiducial marker distortion obtained from the image acquired by the wrist camera. This resulted in a quantitative analysis of the limitations of this approach that only computes local calibration planes, highlighting the reduction of performances observed. Hence, the analysis focused on the comparison between two traditional calibration methods involving rigid markers to determine the best number of calibration points to adopt to achieve good repeatability performances. The analysis shows that, among the three methods, the RPS one resulted in very poor repeatability performances (1.42 mm), while the three and five points calibration methods achieve lower values (0.33 mm and 0.12 mm, respectively) which are closer to the reference repeatability (0.08 mm). Moreover, comparing the overall calibration times achieved by the three methods, it is shown that, incrementing the number of calibration points to more than five, it is not suggested since it could lead to a plateau in the performances, while increasing the overall calibration time.

scholarly journals Improvement of Hargreaves–Samani Reference Evapotranspiration Estimates with Local Calibration

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2272 ◽  
Author(s):  
Daniel Althoff ◽  
Robson Argolo dos Santos ◽  
Helizani Couto Bazame ◽  
Fernando França da Cunha ◽  
Roberto Filgueiras
Keyword(s):  
Reference Evapotranspiration ◽  
Eastern Region ◽  
Local Calibration ◽  
Middle Portion ◽  
Wet Season ◽  
Water Shortages ◽  
Simple Method ◽  
Irrigation Water Management ◽  
Single Calibration ◽  
Separate Calibration

Improving irrigation water management is an important asset when facing increased water shortages. The Hargreaves–Samani (HS) method is a simple method that can be used as an alternative to the Penman–Monteith (PM) method, which requires only temperature measurements for estimating reference evapotranspiration (ETo). However, the applicability of this method relies on its calibration to local meteorological specificities. The objective of this study was to investigate the effects of local calibration on the performance of the HS equation. The study was carried out for the middle portion of the São Francisco River Basin (MSFB), Brazil, and considered four calibration approaches: A1—single calibration for the entire MSFB; A2—separate calibration by clusters of months; A3—by clusters of stations; and A4—for all contexts resulting by combining A2 and A3. Months from the wet season showed larger improvements by the calibration of the HS model, since mean air temperature and its daily range showed stronger correlations to ETo. On the other hand, the months from the dry season and stations from the eastern region of MSFB performed poorly regardless of the calibration approach adopted. This occurred because, in those cases, ETo presented larger correlation to variables that are missing in the HS equation, and the use of the full PM equation seems unavoidable.

Multicenter Evaluation of Lyophilized and Deep-frozen Plasmas for Assignment of the International Normalized Ratio

1999 ◽  
Vol 82 (11) ◽  
pp. 1451-1455 ◽  
Author(s):  
L. L. Houbouyan-Reveillard ◽  
M. F. Aillaud ◽  
K. W. E. Denson ◽  
C. Droullé ◽  
M. Johnston ◽  
...  
Keyword(s):  
Prothrombin Time ◽  
External Quality Assessment ◽  
Calibration Procedure ◽  
International Normalized Ratio ◽  
Sensitivity Index ◽  
Local Calibration ◽  
External Quality ◽  
Different Types ◽  
Time Systems ◽  
International Sensitivity Index

SummaryThe interlaboratory variation of the International Normalized Ratio (INR) in various external quality assessment schemes is still relatively high. This is partly caused by inaccuracy of manufacturers’ stated International Sensitivity Index (ISI) and/or local instrumentation effects. The interlaboratory variation and accuracy of INR determinations may be improved by a local calibration procedure based on lyophilized plasmas with assigned INRs. The purpose of the present study was to determine INR values for different types of lyophilized plasmas to be used for local calibration. A total of 13 lyophilized plasmas (one normal, six from coumarin-treated patients, six artificially depleted) were analyzed by 10 laboratories, each using five calibrated prothrombin time (PT) systems. INRs were calculated for each plasma using each laboratory’s specific ISI and mean normal prothrombin time values. In the same way, five deep-frozen pooled plasmas from coumarin-treated patients were analyzed. There were significant INR differences for the lyophilized plasmas between the prothrombin time systems. The differences were relatively small for the deep-frozen coumarin plasmas (CV 2.6-3.3%) and three lyophilized coumarin plasmas from one manufacturer (CV 3.7-4.8%). Important INR differences were observed for three lyophilized coumarin plasmas from another manufacturer (CV 9.5-14.1%) and several artificially depleted plasmas (CV 5.3-12.8%). The citrate concentrations in the artificially depleted plasmas were lower than those in the normal and coumarin plasmas. These differences should be considered in the selection and certification of plasmas as calibrants for local calibration of PT systems. The lyophilized plasmas’ INR values obtained in the present study will be used for a field study of local PT calibration to assess their efficacy.

Approaches for local calibration of mechanistic-empirical pavement design guide joint faulting model: a case study of Ontario

2018 ◽  
Vol 21 (11) ◽  
pp. 1347-1361 ◽  
Author(s):  
Shi Dong ◽  
Jian Zhong ◽  
Susan L. Tighe ◽  
Peiwen Hao ◽  
Daniel Pickel
Keyword(s):  
Pavement Design ◽  
Local Calibration ◽  
Design Guide

Local Calibration of MEPDG for Flexible Pavements in New Mexico

2013 ◽  
Vol 139 (10) ◽  
pp. 981-991 ◽  
Author(s):  
Rafiqul Tarefder ◽  
Jose I. Rodriguez-Ruiz
Keyword(s):  
New Mexico ◽  
Flexible Pavements ◽  
Local Calibration
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