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Journal articles on the topic 'Measurement errors'
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Qin, Lihou, Qijing Liu, Maozhen Zhang, and Sajjad Saeed. "Effect of measurement errors on the estimation of tree biomass." Canadian Journal of Forest Research 49, no. 11 (November 2019): 1371–78. http://dx.doi.org/10.1139/cjfr-2019-0034.
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Diameter at breast height (DBH) is commonly used to predict the aboveground biomass (AGB) of forests and to derive biomass models for single trees; however, there is evidence that measurement errors of DBH have not been previously considered. In this study, two types of measurement errors were evaluated: errors in national forest inventory data (NFID) and errors in a calibration data set (CDS). Using Monte Carlo simulations, the uncertainties arising from these two measurement errors were quantified. In addition, the effects of measurement errors on estimates under different error assumptions were analyzed to determine how these two uncertainties change with increasing errors. The results show that CDS measurement error contributes more to the total uncertainty, whereas NFID measurement error has a negligible effect on estimating the biomass of regional forests. The uncertainties of both types of measurement error increased with increasing error assumptions; however, the uncertainties caused by CDS measurement error were noticeably larger than those caused by NFID measurement error. Thus, the greatest potential for reducing uncertainties caused by measurement error lies in increasing the accuracy of DBH measurements in CDS.
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Iskenderzade, E. B., E. D. Suleymanova, and H. S. Veliyev. "THE METHOD OF INDIRECT TWO-PART MEASUREMENTS FOR THE CONTROL OF PRODUCTION INDICATORS." Kontrol'. Diagnostika, no. 295 (January 2023): 30–32. http://dx.doi.org/10.14489/td.2023.01.pp.030-032.
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A method of indirect two-part measurements of production indicators, including two independent measurements, has been developed. An elementary example of such measurements is the measurement of rectangular areas, determination of the specific gravity of the material, etc. According to the proposed method, minimization of the total random error of indirect two-part measurement can be carried out in two cases: 1) if it is known about the equality of the total error in both measurements, but the sum of systematic errors is limited from above, then it is possible to solve the problem of determining systematic errors separately, which minimizes the total random error of a two-part indirect measurement; 2) if it is known about the equality of systematic errors in both measurements, but the sum of systematic errors is limited from above, then it is possible to solve the problem of determining the total errors separately, which minimizes the total random error of an indirect two-part measurement.
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Jacob, Vinodkumar, M. Bhasi, and R. Gopikakumari. "Impact of Human Factors on Measurement Errors." International Journal of Measurement Technologies and Instrumentation Engineering 1, no. 4 (October 2011): 28–44. http://dx.doi.org/10.4018/ijmtie.2011100103.
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Measurement is the act or the result, of a quantitative comparison between a given quantity and a quantity of the same kind chosen as a unit. It is for observing and testing scientific and technological investigations and generally agreed that all measurements contain errors. In a measuring system where both a measuring instrument and a human being taking the measurement using a preset process, the measurement error could be due to the instrument, the process or human error. This study is devoted to understanding the human errors in measurement. Work and human involvement related factors that could affect measurement errors have been identified. An experimental study has been conducted using different subjects where the factors were changed one at a time and the measurements made by them recorded. Errors in measurement were then calculated and the data so obtained was subject to statistical analysis to draw conclusions regarding the influence of different factors on human errors in measurement. The findings are presented in the paper.
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Rycroft, M. J. "Measurement errors." Journal of Atmospheric and Terrestrial Physics 57, no. 13 (November 1995): 1673. http://dx.doi.org/10.1016/0021-9169(95)90045-4.
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Wing, Michael G., and Jereme Frank. "An Examination of Five Identical Mapping-Grade Global Positioning System Receivers in Two Forest Settings." Western Journal of Applied Forestry 26, no. 3 (July 1, 2011): 119–25. http://dx.doi.org/10.1093/wjaf/26.3.119.
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Abstract We collected measurements using five identical high-quality mapping-grade GPS receivers that were configured the same and collected data simultaneously in two distinctly different settings within a forest. Our primary objective was to determine whether measurement accuracies were different among the mapping-grade GPS receivers. A secondary objective was to determine whether measurement accuracies were different depending on whether receivers established their locations by taking a single 1-second measurement or by averaging 30 or 60 measurements. In the open-sky setting, where receivers had few obstructions overhead, we found that all five receivers recorded measurements with similar positional accuracies. Errors were lower when measurements were differentially corrected (postprocessed). We found an average error of 1.6 m for unprocessed data and an average error of 0.2 m for postprocessed data. Our results indicate that in open-sky conditions, all five receivers performed similarly when measurements were postprocessed. In addition, there was no significant difference in accuracy whether 1, 30, or 60 points were averaged, regardless of whether data were postprocessed. In the young-forest test course, examination of errors between receivers revealed that one receiver had significantly different errors compared with other receivers, which was likely the result of environmental influences on satellite signal strength and availability. We also found that measurement errors for all five receivers were significantly lower when measurements were postprocessed. On average, measurement errors were 5.9 m for unprocessed data and 1.4 m for postprocessed data. In analyzing individual receiver errors, no receiver had significantly different measurement errors whether 1, 30, or 60 measurements were recorded.
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Wolf, Matthew B. "Hemoglobin-Dilution Method: Effect of Measurement Errors on Vascular Volume Estimation." Computational and Mathematical Methods in Medicine 2017 (2017): 1–5. http://dx.doi.org/10.1155/2017/3420590.
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The hemoglobin-dilution method (HDM) has been used to estimate changes in vascular volumes in patients because direct measurements with radioisotopes are time-consuming and not practical in many facilities. The HDM requires an assumption of initial blood volume, repeated measurements of plasma hemoglobin concentration, and the calculation of the ratio of hemoglobin measurements. The statistics of these ratio distributions resulting from measurement error are ill-defined even when the errors are normally distributed. This study uses a “Monte Carlo” approach to determine the distribution of these errors. The finding was that these errors could be closely approximated with a log-normal distribution that can be parameterized by a geometric mean (X) and a dispersion factor (S). When the ratio of successive Hb concentrations is used to estimate blood volume, normally distributed hemoglobin measurement errors tend to produce exponentially higher values ofXandSas the SD of the measurement error increases. The longer tail of the distribution to the right could produce much greater overestimations than would be expected from the SD values of the measurement error; however, it was found that averaging duplicate and triplicate hemoglobin measurements on a blood sample greatly improved the accuracy.
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Huang, Yubin, Xiong Zhang, Kaisi You, Jihong Chen, Hao Zhou, and Hua Xiang. "Drifted Uncertainty Evaluation of a Compact Machine Tool Spindle Error Measurement System." Machines 12, no. 10 (October 1, 2024): 695. http://dx.doi.org/10.3390/machines12100695.
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The accurate measurement of spindle errors, especially quasi-static errors, is one of the key issues for the analysis and compensation of machine tool thermal errors in machining accuracy. To quantitatively analyze the influence of the measurement system’s own drift on the measurement results, a drifted uncertainty evaluation method of the precision instrument considering the time drift coefficient is proposed. This study also produced a high-precision compact spindle error measurement device (with a displacement measurement error of less than ±1.33 μm and an angular measurement error of less than ±1.42 arcsecs) as the research object to verify the proposed drift uncertainty evaluation method. A method for evaluating the drift uncertainty of the measurement system is proposed to quantitatively evaluate the system error and drift uncertainty of the measurement device. Experiments show that the drift uncertainty evaluation method proposed in this paper is more suitable for evaluating the uncertainty changes in measurement instruments during long-term measurements compared to traditional methods.
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Singh, Ravi Shankar, Helko van den Brom, Stanislav Babaev, Sjef Cobben, and Vladimir Ćuk. "Estimation of Impedance and Susceptance Parameters of a 3-Phase Cable System Using PMU Data." Energies 12, no. 23 (November 30, 2019): 4573. http://dx.doi.org/10.3390/en12234573.
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This paper proposes a new regression-based method to estimate resistance, reactance, and susceptance parameters of a 3-phase cable segment using phasor measurement unit (PMU) data. The novelty of this method is that it gives accurate parameter estimates in the presence of unknown bias errors in the measurements. Bias errors are fixed errors present in the measurement equipment and have been neglected in previous such attempts of estimating parameters of a 3-phase line or cable segment. In power system networks, the sensors used for current and voltage measurements have inherent magnitude and phase errors whose measurements need to be corrected using calibrated correction coefficients. Neglecting or using wrong error correction coefficients causes fixed bias errors in the measured current and voltage signals. Measured current and voltage signals at different time instances are the variables in the regression model used to estimate the cable parameters. Thus, the bias errors in the sensors become fixed errors in the variables. This error in variables leads to inaccuracy in the estimated parameters. To avoid this, the proposed method uses a new regression model using extra parameters which facilitate the modeling of present but unknown bias errors in the measurement system. These added parameters account for the errors present in the non- or wrongly calibrated sensors. Apart from the measurement bias, random measurement errors also contribute to the total uncertainty of the estimated parameters. This paper also presents and compares methods to estimate the total uncertainty in the estimated parameters caused by the bias and random errors present in the measurement system. Results from simulation-based and laboratory experiments are presented to show the efficacy of the proposed method. A discussion about analyzing the obtained results is also presented.
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ISKANDAROV, NABI, ELMIN BAGISHOV, and ELCHIN ISGANDARZADA. "EFFECT OF SURFACE SENSOR AND EXTERNAL REFERENCE NODE ON PROCESS TEMPERATURE MEASUREMENT ACCURACY." Computational Nanotechnology 9, no. 1 (March 28, 2022): 145–53. http://dx.doi.org/10.33693/2313-223x-2022-9-1-145-153.
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As we know, one of the most important and important issues in the implementation of technological processes is the implementation of accurate and correct temperature measurements. During the research, attention was paid to the measurement errors in temperature measurements of technological processes using thermocouples and methods of minimizing those errors. In addition, errors in thermocouple temperature measurements were briefly discussed, and for temperatures limited to a certain range, the T-type thermocouple achieved several times less error than the allowable error specified in the normative documents. It is known that when describing thermocouples in the technical literature, first of all, industrial devices with high temperature coefficient and medium class accuracy are considered. Also, as we know, in domestic applications, the temperature difference between the measurement and the reference node varies mainly within the minimum threshold range. Therefore, if the main source of error is the internal reference temperature compensation in the measuring instrument, it is almost impossible to determine the proportion of errors due to the thermocouple itself. The study found that the measurement error can be significantly reduced when determining the temperature of technological processes using an external reference node. At the same time, since the special application of temperature measurements of technological processes covers the measurement of indoor and outdoor temperatures, the errors due to the effect of radiation on the sensor from the surrounding surfaces are many times higher than the allowable error. For this reason, tools have been proposed to assess the radiation effects on typical thermocouples, along with proposals for modification of thermocouple sensors to reduce the potential radiation exposure and thus increase measurement accuracy.
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Zhukov, Leonid, and Dmytro Petrenko. "INFLUENCE OF OBJECT AND PYROMETRIC SYSTEM OPTICAL CHARACTERISTICS ON ERRORS OF INDIRECT EMISSIVITY AND TEMPERATURE MEASUREMENTS." System Research in Energy 2023, no. 1 (April 7, 2023): 55–71. http://dx.doi.org/10.15407/srenergy2023.01.055.
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The present article aims to study the influence of the optical characteristics of a thermometered object and a pyrometric system on measurement errors of emissivity and temperature. The analysis and classification of factors that determine methodical and instrumental measurement errors have been performed. The expressions which determine the complex multifactorial influence of object and system optical characteristics on methodical and instrumental errors have been derived. On the base of obtained expressions, the influence of the optical characteristics of a thermometered object and a pyrometric system on these errors is analyzed. The dominant influence of the optical characteristics of a thermometered object on methodical errors of emissivity and temperature measurements has been established. The influence of a system`s optical characteristics on methodical errors of emissivity and temperature measurements has been studied under conditions of wide and real thermometered object characteristics ranges of changes. As a result, a significant reduction of methodical errors was achieved by optimizing the optical characteristics of the system. Under conditions of fixed object characteristics and operating wavelengths of a system, the influence regularities of primary pyrometric information errors (operating wavelengths setting and one-color radiation temperatures measurements) on the instrumental errors have been obtained. A significant influence of the signs and modules of primary pyrometric information errors on them has been established. Instrumental errors are minimal in the case of identical signs of primary pyrometric information errors for all operating waves, and maximum in the case of different signs for the middle and boundary waves. With the same signs and modules of one-color radiation temperatures measurement errors, the instrumental error of temperature measurements does not exceed their modules. Keywords: temperature, spectral distribution of emissivity, two-color compensative thermometry, linear method, methodical and instrumental components of measurement error.
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Wan, Peng, Jun Jie Guo, and Hai Tao Li. "Study on the Method of Error Identification and Compensation for Gear Measuring Center." Advanced Materials Research 482-484 (February 2012): 1821–28. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1821.
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Gear Measuring Center(GMC) is commonly used to test error of the tooth surface of the gear, whose geometric accuracy directly impacts on the accuracy of measurement. How to quickly and accurately detect space geometric error of the measuring machine and compensate becomes the essential means of high-precision measurements. According to the problem above, in the paper, three-beams laser detection technology is proposed. The detection of the geometric errors of the linear axis was achieved. The accurate measurement for the position and attitude of the plane mirror on measurement seat was achieved based on laser telemetry principle. The positioning error, the pitching angle errors, the deflection angle errors and the straightness errors were separated. And then based on multi-body system theory, by using of homogeneous coordinate transformation, the error compensation model of 4-axis measuring machine which includes three shifting pairs and one revolute pair was established, and the algorithm was given in the paper. The theoretical foundation for real-time compensation of 4-axis GMC was established. The geometric errors of GMC can be improved by the method of the error detection and compensation. The method plays a very important role in high-precision measurements.
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Cho, JoonHwan, Yao Luo, and Ruli Xiao. "Deconvolution from two order statistics." Quantitative Economics 15, no. 4 (2024): 1065–106. http://dx.doi.org/10.3982/qe2077.
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Economic data are often contaminated by measurement errors and truncated by ranking. This paper shows that the classical measurement error model with independent and additive measurement errors is identified nonparametrically using only two order statistics of repeated measurements. The identification result confirms a hypothesis by Athey and Haile (2002) for a symmetric ascending auction model with unobserved heterogeneity. Extensions allow for heterogeneous measurement errors, broadening the applicability to additional empirical settings, including asymmetric auctions and wage offer models. We adapt an existing simulated sieve estimator and illustrate its performance in finite samples.
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Jiang, Zhichao, and Peng Ding. "Measurement errors in the binary instrumental variable model." Biometrika 107, no. 1 (November 21, 2019): 238–45. http://dx.doi.org/10.1093/biomet/asz060.
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Summary Instrumental variable methods can identify causal effects even when the treatment and outcome are confounded. We study the problem of imperfect measurements of the binary instrumental variable, treatment and outcome. We first consider nondifferential measurement errors, that is, the mismeasured variable does not depend on other variables given its true value. We show that the measurement error of the instrumental variable does not bias the estimate, that the measurement error of the treatment biases the estimate away from zero, and that the measurement error of the outcome biases the estimate toward zero. Moreover, we derive sharp bounds on the causal effects without additional assumptions. These bounds are informative because they exclude zero. We then consider differential measurement errors, and focus on sensitivity analyses in those settings.
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Hegsted, D. M. "Errors of measurement." Nutrition and Cancer 12, no. 2 (January 1989): 105–7. http://dx.doi.org/10.1080/01635588909514008.
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Zemel'man, M. A. "Classifying measurement errors." Measurement Techniques 28, no. 6 (June 1985): 471–75. http://dx.doi.org/10.1007/bf00864048.
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R. Ziyatdinov, Rustem, and Leisan R. Zakirova. "Application of Measurement Signal Reduction to Improve Measurement Accuracy." International Journal of Engineering & Technology 7, no. 4.36 (December 9, 2018): 1035. http://dx.doi.org/10.14419/ijet.v7i4.36.24948.
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Most modern technical tasks require high precision measurements. To do this, it is necessary to analyze the causes of errors and take measures to reduce their influence on the accuracy of measurements. The causes of errors are very diverse and cannot always be identified. However, some systematic components of the measurement error can be described and calculated mathematically. In this case, the task of reducing the signal at the output of a measuring device to the form it would have when using an “ideal” device is reduced to calculating a certain linear operator which product to the measured signal allows obtaining the minimum systematic error. In this paper, the application of the reduction method is given by the example of a measuring instrument for the degree of polarization of light radiation which comprises three measuring channels for measuring the intensity of linearly polarized radiation. Each channel is built with the use of three operational amplifiers. The main errors of a measuring channel that can be described and determined are the errors of the operational amplifiers associated with the bias voltages and temperature drift. In real measuring systems there are much larger of such components. However, the use of computer equipment for modeling systems and processes, as well as measurements, removes all restrictions on the possibilities of processing the obtained data in a software way. With the help of computer technology it is possible to reduce the influence of perturbing effects and systematic errors, and also to eliminate gross errors. The random component of an error can be reduced by increasing the number of measurements and carrying out statistical data processing.
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de Wit, C. "Optimal Position Estimate from a Stars Fix with Correlated Errors." Journal of Navigation 45, no. 1 (January 1992): 126–33. http://dx.doi.org/10.1017/s0373463300010535.
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This paper concerns the estimate of a ship's position from a sequence of measurements of 3, 4 or 5 altitudes of stars or planets. The measurement errors are assumed to be mutually correlated. This correlation is mainly caused by the appearance of so-called systematic errors. It is the main intention of this paper to dispense with the policy of pre-separation of these systematic errors. Instead, the equal contribution of some partial errors to the total measuring errors is fully accounted for by the formation of the covariance matrix, which corresponds with the vector of measurement errors. The algorithm produces a position estimate with a bias-free estimation error, meaning that the estimate and the error are stochastically independent. The resulting covariance matrix of the position error has a minimal trace.
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Mehtätalo, Lauri, and Annika Kangas. "An approach to optimizing field data collection in an inventory by compartments." Canadian Journal of Forest Research 35, no. 1 (January 1, 2005): 100–112. http://dx.doi.org/10.1139/x04-139.
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This study presents models for the expected error of the total volume and saw timber volume due to sampling errors of stand measurements. The measurements considered are horizontal point sample plots, stem numbers from circular plots, sample tree heights, sample order statistics (i.e., quantile trees), and sample tree heights from the previous inventory. Different measurement strategies were constructed by systematically varying the numbers of these measurements. A model system developed for this study was used in a data set of 170 stands to predict the total volume and saw timber volume of each stand with each measurement strategy. The errors of these volumes were modeled using stand characteristics and the numbers of measurements as predictors. The most important factors affecting the error in the total volume were the number of horizontal point sample plots and height sample trees. In addition, the number of quantile trees had a strong effect on the error of saw timber volume. The errors were slightly reduced when an old height measurement was used. There were significant interactions between stand characteristics and measurement strategies. Thus, the optimal measurement strategy varies between stands. A demonstration is provided of how constrained optimization can be used to find the optimal strategy for any one stand.
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Napper, John. "Economic Consequences of Measurement Errors." Measurement and Control 19, no. 5 (June 1986): 59–62. http://dx.doi.org/10.1177/002029408601900507.
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In this article John Napper highlights the monetary effect of measurement errors for the loading of road tankers. His example of a terminal with 40 million litres per month where 0.1% error is equivalent to £200,000 per annum highlights the problem. He indicates sources of error and the way that microprocessors can control errors and thereby avoid the large financial consequences.
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Chen, Peng, and Huang. "A New Error Model and Compensation Strategy of Angle Encoder in Torsional Characteristic Measurement System." Sensors 19, no. 17 (August 30, 2019): 3772. http://dx.doi.org/10.3390/s19173772.
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For systems of measurement, geometric errors such as manufacturing and assembly errors could have a significant impact on the accuracy of the angle encoders of the system. In this study, an error model of angular measurement with geometric errors of a torsional characteristic measurement system was developed based on multibody system theory, the aim of which was to reveal the impact of geometric errors on angular measurement and to compensate the measurement error. According to the principle of spatial error transfer, the decomposition of geometric errors is illustrated and the error matrix of geometric errors is constructed by the Denavit–Hartenberg (DH) method. Subsequently, an error compensation function can be obtained and the impact of geometric error on angular measurement is discussed. Finally, we demonstrate by the experimental results of an ultra-autocollimator that the proposed error compensation method reduced the angular measurement error from 3.7% to 0.7%, which shows that the proposed error model can effectively predict the angular measurement error. In addition, it can be seen from the measurement results of the RV reducer that the error of the torsional characteristic measurement system decreased significantly.
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Andersen, C. M., R. Bro, and P. B. Brockhoff. "Quantifying and handling errors in instrumental measurements using the measurement error theory." Journal of Chemometrics 17, no. 12 (December 2003): 621–29. http://dx.doi.org/10.1002/cem.830.
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Schifeling, Tracy, Jerome P. Reiter, and Maria Deyoreo. "Data Fusion for Correcting Measurement Errors." Journal of Survey Statistics and Methodology 7, no. 2 (May 25, 2018): 175–200. http://dx.doi.org/10.1093/jssam/smy010.
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AbstractOften in surveys, key items are subject to measurement errors. Given just the data, it can be difficult to determine the extent and distribution of this error process and, hence, to obtain accurate inferences that involve the error-prone variables. In some settings, however, analysts have access to a data source on different individuals with high-quality measurements of the error-prone survey items. We present a data fusion framework for leveraging this information to improve inferences in the error-prone survey. The basic idea is to posit models about the rates at which individuals make errors, coupled with models for the values reported when errors are made. This can avoid the unrealistic assumption of conditional independence typically used in data fusion. We apply the approach on the reported values of educational attainments in the American Community Survey, using the National Survey of College Graduates as the high-quality data source. In doing so, we account for the sampling design used to select the National Survey of College Graduates. We also present a process for assessing the sensitivity of various analyses to different choices for the measurement error models. Supplemental material is available online.
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Hsu, Chi-Hua, Jr-Rung Chen, Fan-Hsi Hsu, and Yu-Ta Chen. "A Novel Measurement Method for Determining Geometric Errors of Rotary Tables by Using LaserTRACER and Reflectors." Applied Sciences 13, no. 4 (February 13, 2023): 2419. http://dx.doi.org/10.3390/app13042419.
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In this paper, a novel and robust measurement method is proposed for obtaining the geometric errors of rotary tables by using LaserTRACER and the reflectors mounted on the reflector standard fixture. For the machining accuracy, the six-degree-of-freedom (6-DOF) geometric errors of the rotary axes interactively influence the manufacturing quality of the precise workpieces. Therefore, this paper mainly aims to develop a measurement method for identifying the 6-DOF geometric errors of rotary tables without using the external linear axis. Furthermore, the set-up errors of the reflector standard fixture are also considered and identified to reduce the influence of the 6-DOF geometric error measurements. For each rotary table geometric error measurement, the positions of the LaserTRACER as well as the relative distance between the reflectors and the LaserTRACER are measured and obtained for determining the 6-DOF geometric errors of the rotary tables. In addition, the homogeneous transformation matrix (HTM), multilateration method, and least squares method are used for building the mathematical measurement algorithm. Moreover, the experimental verifications are implemented to demonstrate the accuracy of the proposed measurement method. Conclusively, the experiment and simulation verification results clearly delineate that the maximal relative differences in the linear errors and the angular errors of the 6-DOF geometric errors are, at most, 3.25% and 2.30%, respectively.
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Hong, Hanwoom, Sung K. Ahn, and Sinsup Cho. "Estimation of error correction model with measurement errors." Journal of Statistical Computation and Simulation 90, no. 9 (April 3, 2020): 1661–80. http://dx.doi.org/10.1080/00949655.2020.1743991.
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Zhou, Jun Wei, Lin He, and Rong Wu Xu. "Typical Errors Analysis in Frequency Response Function Measurement." Applied Mechanics and Materials 419 (October 2013): 470–76. http://dx.doi.org/10.4028/www.scientific.net/amm.419.470.
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FRF measurements can suffer from various errors. The effect of deterministic errors become more prominent compared to random errors in FRF measurement. Excitation and sensor misalignment is the most common source of deterministic error, so mathematic model is established and the effect on FRF estimation was analyzed for senor and excitation misalignment situations. Finite element model simulation reveals that misalignment error can have the least effect on the dominant FRFs and a stronger effect on lesser FRFs, beside that it also results in the appearance of false peaks in the measured FRFs.
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Tarkkonen, L., and K. Vehkalahti. "Measurement errors in multivariate measurement scales." Journal of Multivariate Analysis 96, no. 1 (September 2005): 172–89. http://dx.doi.org/10.1016/j.jmva.2004.09.007.
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Haah, Jeongwan, and Matthew B. Hastings. "Measurement sequences for magic state distillation." Quantum 5 (January 20, 2021): 383. http://dx.doi.org/10.22331/q-2021-01-20-383.
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Magic state distillation uses special codes to suppress errors in input states, which are often tailored to a Clifford-twirled error model. We present detailed measurement sequences for magic state distillation protocols which can suppress arbitrary errors on any part of a protocol, assuming the independence of errors across qubits. Provided with input magic states, our protocol operates on a two-dimensional square grid by measurements of ZZ on horizontal pairs of qubits, XX on vertical pairs, and Z,X on single qubits.
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Shettles, Michael, Thomas Hilker, and Hailemariam Temesgen. "Examination of uncertainty in per unit area estimates of aboveground biomass using terrestrial LiDAR and ground data." Canadian Journal of Forest Research 46, no. 5 (May 2016): 706–15. http://dx.doi.org/10.1139/cjfr-2015-0265.
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In estimating aboveground forest biomass (AGB), three sources of error that interact and propagate include (i) measurement error, the quality of the tree-level measurement data used as inputs for the individual-tree equations; (ii) model error, the uncertainty about the equations of the individual trees; and (iii) sampling error, the uncertainty due to having obtained a probabilistic or purposive sample, rather than a census, of the trees on a given area of forest land. Monte Carlo simulations were used to examine measurement, model, and sampling errors and to compare total uncertainty between models and between a phase-based terrestrial laser scanner (TLS) and traditional forest inventory instruments. Input variables for the equations were diameter at breast height, total tree height (defined the height from the uphill side of the tree to the tree top), and height to crown base; these were extracted from the terrestrial LiDAR data. Relative contributions for measurement, model, and sampling errors were 5%, 70%, and 25%, respectively, when using TLS, and 11%, 66%, and 23%, respectively, when using the traditional inventory measurements as inputs into the models. We conclude that the use of TLS can reduce measurement errors of AGB compared with traditional inventory measurements.
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Ni, J., P. S. Huang, and S. M. Wu. "A Multi-Degree-of-Freedom Measuring System for CMM Geometric Errors." Journal of Engineering for Industry 114, no. 3 (August 1, 1992): 362–69. http://dx.doi.org/10.1115/1.2899804.
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A precision multi-degree-of-freedom measuring (MDFM) system has been developed and implemented for the simultaneous measurement of straightness, pitch, yaw, and roll errors of the moving axes of a CMM. The system is based on the principles of laser alignment and autocollimator. Its measurement principles and the influence of laser beam drifts on its measurement quality have been investigated and some improvement schemes have been implemented. Through the measurements of actual as well as artificially created geometric errors of the CMM, it has been found that the system’s accuracy of measuring straightness error components is better than 1 μm and its accuracy for angular error measurements is better than 0.5 arcsec.
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Adamczak, Stanisław, Jacek Świderski, and Urszula Kmiecik-Sołtysiak. "Estimation of the uncertainty of the roundness measurement with a device with rotary spindle." Mechanik 90, no. 10 (October 9, 2017): 912–14. http://dx.doi.org/10.17814/mechanik.2017.10.145.
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The paper presents the estimation of uncertainty of roundness measurement using the Talyrond 73 by analyzing the sources of measurement errors such as measuring noise, signal drift, radial spindle error, repeatability, sensor gain error and uncertainty of measurement standards. The study included the following measurements: roller bearing, glass hemisphere and flick standard.
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Klems, J. H. "Measurement of Fenestration Net Energy Performance: Considerations Leading to Development of the Mobile Window Thermal Test (MoWitt) Facility." Journal of Solar Energy Engineering 110, no. 3 (August 1, 1988): 208–16. http://dx.doi.org/10.1115/1.3268259.
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We present a detailed consideration of the energy flows entering a building space and the effect of random measurement errors on determining fenestration performance. Estimates of error magnitudes are made for a passive test cell; we show that a more accurate test facility is needed for reliable measurements on fenestration systems with thermal resistance 2–10 times that of single glazing or with shading coefficients less than 0.7. A test facility of this type, built at Lawrence Berkeley Laboratory, is described. The effect of random errors in this facility is discussed and computer calculations of its performance are presented. The discussion shows that, for any measurement facility, random errors are most serious in nighttime measurements, and systematic errors are most important in daytime measurements. It is concluded that, for this facility, errors from both sources should be small.
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Tu, Jia, Defeng Gu, Yi Wu, and Dongyun Yi. "Error Modeling and Analysis for InSAR Spatial Baseline Determination of Satellite Formation Flying." Mathematical Problems in Engineering 2012 (2012): 1–23. http://dx.doi.org/10.1155/2012/140301.
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Spatial baseline determination is a key technology for interferometric synthetic aperture radar (InSAR) missions. Based on the intersatellite baseline measurement using dual-frequency GPS, errors induced by InSAR spatial baseline measurement are studied in detail. The classifications and characters of errors are analyzed, and models for errors are set up. The simulations of single factor and total error sources are selected to evaluate the impacts of errors on spatial baseline measurement. Single factor simulations are used to analyze the impact of the error of a single type, while total error sources simulations are used to analyze the impacts of error sources induced by GPS measurement, baseline transformation, and the entire spatial baseline measurement, respectively. Simulation results show that errors related to GPS measurement are the main error sources for the spatial baseline determination, and carrier phase noise of GPS observation and fixing error of GPS receiver antenna are main factors of errors related to GPS measurement. In addition, according to the error values listed in this paper, 1 mm level InSAR spatial baseline determination should be realized.
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Kwon, H. D., and M. Burdekin. "Measurement and diagnostics of machine tool errors during circular contouring motions." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 212, no. 5 (May 1, 1998): 343–56. http://dx.doi.org/10.1243/0954405981515950.
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This paper deals with the measurement and diagnosis of the machine tool errors by application of the ball link bar system. It includes the development of a new link bar, the in-plane and out-of-plane measurement techniques and the machine error analysis system. The new type of ball link incorporates an idealized three-point kinematic contact principle between the balls and sockets of the link bar, and provides the following features: (a) the minimum length of the link corresponds to the minimum length of a standard LVDT transducer, (b) the link is of light weight, (c) the accuracy and the repeatability of the link corresponds to that of the LVDT (linear variable differential transformer) transducer and (d) the link is mounted between two reference balls by using the spring force of the LVDT transducer and thereby eliminating the need for magnets as in the case of the conventional double-ball bar. With the in-plane and out-of-plane measurements under different test conditions, the machine errors, such as set-up errors, closing errors, backlash errors, dynamic backlash errors, positional errors, pitch motion errors, transient errors around the start point of the test path, vibration due to too high a gain setting, stick-slip errors, squareness errors and servo mis-match errors, can be analysed by the application of the machine error analysis software. Practical measurements on the TAKISAWA CNC (computerized numerical control) machining centre were carried out and the machine tool errors were effectively evaluated.
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Zhao, Xiaowei, Huifu Du, and Daguo Yu. "Improving Measurement Accuracy of Deep Hole Measurement Instruments through Perspective Transformation." Sensors 24, no. 10 (May 16, 2024): 3158. http://dx.doi.org/10.3390/s24103158.
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Deep hole measurement is a crucial step in both deep hole machining and deep hole maintenance. Single-camera vision presents promising prospects in deep hole measurement due to its simple structure and low-cost advantages. However, the measurement error caused by the heating of the imaging sensor makes it difficult to achieve the ideal measurement accuracy. To compensate for measurement errors induced by imaging sensor heating, this study proposes an error compensation method for laser and vision-based deep hole measurement instruments. This method predicts the pixel displacement of the entire field of view using the pixel displacement of fixed targets within the camera’s field of view and compensates for measurement errors through a perspective transformation. Theoretical analysis indicates that the perspective projection matrix changes due to the heating of the imaging sensor, which causes the thermally induced measurement error of the camera. By analyzing the displacement of the fixed target point, it is possible to monitor changes in the perspective projection matrix and thus compensate for camera measurement errors. In compensation experiments, using target displacement effectively predicts pixel drift in the pixel coordinate system. After compensation, the pixel error was suppressed from 1.99 pixels to 0.393 pixels. Repetitive measurement tests of the deep hole measurement instrument validate the practicality and reliability of compensating for thermal-induced errors using perspective transformation.
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Lee, Tae-Ho, Ki-Soo Lee, Jong-Hyun Nam, and Yoon-Goo Kang. "Comparison of measurement errors between conventional, digital cephalographs and hardcopies." Journal of The Korean Dental Association 47, no. 5 (May 31, 2009): 282–90. http://dx.doi.org/10.22974/jkda.2009.47.5.004.
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The purpose of this study was to evaluate the measurement error between conventional films, digital cephalographs and hardcopy. The material consisted of 29 cephalographs which used image modality of Asahi CX-90SP in the Kyung Hee University Dental Hospital. One observer measured fiducial measurements at an interval of four weeks. Measurement error was tested by Dahlberg's formula. A paired t-test was used to detect it between each modality. The results are as follows; 1. The monitor-displayed digital image showed enlargement compared with the conventional image. The cephalometric measurements of the monitor-displayed digital image and conventional image were no statistically significant difference except SNB. 2. In conventional image, measurement errors of linear and angular measurements were 0.23mm, 0.36°, respective. In monitor-displayed digital image, measurement errors of linear and angular measurements were 0.63mm, 0.48° respective. 3. The reduction ratio of hardcopy was 1.01% compared to the monitor-displayed digital image. Based on the results, it indicates that the digital cephalographs and hardcopy using storage phosphor digital radiography showed the same accuracy as the conventional films in clinical use.
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Baker, D. F., H. Bösch, S. C. Doney, D. O'Brien, and D. S. Schimel. "Carbon source/sink information provided by column CO<sub>2</sub> measurements from the Orbiting Carbon Observatory." Atmospheric Chemistry and Physics 10, no. 9 (May 3, 2010): 4145–65. http://dx.doi.org/10.5194/acp-10-4145-2010.
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Abstract. We quantify how well column-integrated CO2 measurements from the Orbiting Carbon Observatory (OCO) should be able to constrain surface CO2 fluxes, given the presence of various error sources. We use variational data assimilation to optimize weekly fluxes at a 2°×5° resolution (lat/lon) using simulated data averaged across each model grid box overflight (typically every ~33 s). Grid-scale simulations of this sort have been carried out before for OCO using simplified assumptions for the measurement error. Here, we more accurately describe the OCO measurements in two ways. First, we use new estimates of the single-sounding retrieval uncertainty and averaging kernel, both computed as a function of surface type, solar zenith angle, aerosol optical depth, and pointing mode (nadir vs. glint). Second, we collapse the information content of all valid retrievals from each grid box crossing into an equivalent multi-sounding measurement uncertainty, factoring in both time/space error correlations and data rejection due to clouds and thick aerosols. Finally, we examine the impact of three types of systematic errors: measurement biases due to aerosols, transport errors, and mistuning errors caused by assuming incorrect statistics. When only random measurement errors are considered, both nadir- and glint-mode data give error reductions over the land of ~45% for the weekly fluxes, and ~65% for seasonal fluxes. Systematic errors reduce both the magnitude and spatial extent of these improvements by about a factor of two, however. Improvements nearly as large are achieved over the ocean using glint-mode data, but are degraded even more by the systematic errors. Our ability to identify and remove systematic errors in both the column retrievals and atmospheric assimilations will thus be critical for maximizing the usefulness of the OCO data.
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Yu, Shuang, Haoran Guo, Wenlong Yang, Yanqiao Zhao, Haibin Wu, Xiaoming Sun, and Xiaoyang Yu. "Depth Measurement Error Analysis and Structural Parameter Correction of Structured Light Depth Imager." Photonics 11, no. 5 (April 24, 2024): 396. http://dx.doi.org/10.3390/photonics11050396.
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Considering that structured light depth imagers are difficult to use for precision measurements due to their limited measurement accuracy, we propose an innovative method for correcting structural parameters of structured light depth imagers to reduce the depth measurement error caused by structural parameter errors. For the structured light depth imager, the analytical imaging model is established, and the model of depth error caused by structural parameter errors is established based on the analysis of the depth measurement error analysis. Then, structural parameters are corrected according to the depth measurement error analysis and processing based on experimental depth imaging data of the standard reference plane at the maximum depth. As a result, the corrected analytical imaging model and corrected depth measurement values are obtained. Experimental results have demonstrated the success of this proposed method and its simplicity and convenience.
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Khadanovich, D. V., and V. I. Shiryaev. "ADAPTIVE GUARANTEED ESTIMATION OF A CONSTANT SIGNAL UNDER UNCERTAINTY OF MEASUREMENT ERRORS." Bulletin of the South Ural State University. Ser. Computer Technologies, Automatic Control & Radioelectronics 20, no. 4 (December 2020): 22–36. http://dx.doi.org/10.14529/ctcr200403.
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In the guaranteed estimation problems under uncertainty relative to disturbances and meas-urement errors, the admissible sets of their possible values are determined. The solution is chosen due to conditions of guaranteed bounded estimates optimization corresponding to the worst realiza-tion of disturbances and measurement errors. The result of the guaranteed estimation is an unim-provable bounded estimate (information set), which turns to be overly pessimistic (reinsurance) if a prior admissible set of measurement errors is too large compared to their realized values. The admis-sible sets of disturbances and measurement errors can turn to be only rough upper estimates on a short observation interval. The goal of research is the accuracy enhancement problem of guaran-teed estimation when measurement errors are not realized in the worst way, i.e. the environment in which the object operates does not behave as aggressively as it is built in a priori data on the permis-sible set of error values. Research design. The problem of adaptive guaranteed estimation of a con-stant signal from noisy measurements is considered. The adaptive filtering problem is, according to the results of measurement processing, from the whole set of possible realizations of errors, to choose the one that would generate the measurement sequence. Results. An adaptive guaranteed estimation algorithm is presented. The adaptive algorithm construction is based on a multi-alternative method based on the Kalman filter bank. The method uses a set of filters, each of which is tuned to a specific hypoth-esis about the measurement error model. Filter residuals are used to compute estimates of realized measurement errors. The choice of the realization of possible errors is performed using a function that has the meaning of the residual variance over a short time interval. Conclusion. The computa-tional scheme of the adaptive algorithm, the numerical example, and comparative analysis of ob-tained estimates are presented.
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Avišāne, Anita, Janis Rudzitis, Gunārs Upītis, and Janis Vilcāns. "Influence of Flexible Body Contact Deformation on the Linear Dimension Measurement Precision." Solid State Phenomena 199 (March 2013): 321–25. http://dx.doi.org/10.4028/www.scientific.net/ssp.199.321.
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The common measurement error when measuring the component geometrical dimensions using universal contact measurement instruments is caused by different factors, such as error of the measurement instrument, personal reading errors, effect of surface roughness on the measuring line deviation, influence of contact deformation measurement force, and others. The present article examines one of these factors, i.e. contact deformations under the influence of measurement force. To make precise measurements it is essential to find out the effect of roughness of measured components. High roughness creates additional measurement errors. It is particularly important in the measurement of thin components, flexible materials and films, as well as for components with nanocoating. Flexible bodies in the meaning of this article are components of different shape and sizes made of rubber or soft plastic. This article studies principles of error formation based on the deformation of surface roughness and basic material.
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ur Rehman, Junaid, and Hyundong Shin. "Entanglement-Free Parameter Estimation of Generalized Pauli Channels." Quantum 5 (July 1, 2021): 490. http://dx.doi.org/10.22331/q-2021-07-01-490.
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We propose a parameter estimation protocol for generalized Pauli channels acting on d-dimensional Hilbert space. The salient features of the proposed method include product probe states and measurements, the number of measurement configurations linear in d, minimal post-processing, and the scaling of the mean square error comparable to that of the entanglement-based parameter estimation scheme for generalized Pauli channels. We also show that while measuring generalized Pauli operators the errors caused by the Pauli noise can be modeled as measurement errors. This makes it possible to utilize the measurement error mitigation framework to mitigate the errors caused by the generalized Pauli channels. We use this result to mitigate noise on the probe states and recover the scaling of the noiseless probes, except with a noise strength-dependent constant factor. This method of modeling Pauli channel as measurement noise can also be of independent interest in other NISQ tasks, e.g., state tomography problems, variational quantum algorithms, and other channel estimation problems where Pauli measurements have the central role.
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Антохин, Pavel Antokhin, Дьяконов, and Igor Dyakonov. "INFLUENCE EXTERNAL INFLUENCES ON THE ACCURACY OF TEMPERATURE CONCRETE FEATURES AND PERFORMANCE MEASUREMENT WITH INFRARED TECHNOLOGY IN THE AGING MONOLITHIC STRUCTURES." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 2, no. 3 (April 4, 2017): 57–65. http://dx.doi.org/10.12737/24621.
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At the present stage of technological development, where low labor intensity are highly valued, high efficiency and representativeness of measurements, a convenient means of storing and processing information, the infrared (IR) thermometry recaptures more and more space. The exact definition of the concrete temperature (with an error of 1 °C or less, usually defined by the sensor) is extremely complicated: Instrumental errors superimposed on the error measurement method used, on the errors associated with the arrangement of the measurement sites, etc. In relative terms, the rates of heating-cooling, in the absolute, the range of allowed temperatures when exposed concrete such accuracy looks obviously excessive and unjustified technically and economically. Considering the IR technique as a means postroechnyh control the concrete temperature, and when performing measurements using its implementation should be tailored to suit the IR measurements and factors that can lead to significant measurement errors. Since these factors can greatly affect the measurement result. Reliability indirect MOTB (method of determining the temperature of the concrete) with pyrometers is achieved by using the calculated accurate according to a certain type of decks and compliance with the measurement rules to ensure the work of this relationship within the allowable range of accuracy.
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Tsvetkov, �. I. "Scaling errors in measurements by processor measurement devices." Measurement Techniques 33, no. 4 (April 1990): 291–94. http://dx.doi.org/10.1007/bf00867807.
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Markuze, Yu I., Anh Cuong Le, Thi Thu Nguyen, and Hai Nam Dinh. "Monitoring coarse measurement errors and initial data." Geodesy and Cartography 937, no. 7 (August 20, 2018): 11–16. http://dx.doi.org/10.22389/0016-7126-2018-937-7-11-16.
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Rough errors are a consequence of the observer’s miscalculations, device malfunctions, their displacements at the time of measurement, incorrect measurement techniques chosen, rapid and sharp deterioration of external conditions and other causes. That is why, one of the problems in the theory of mathematical processing geodetic measurements is culling measurements containing gross errors. In the last two decades received recursion equalization has been widespread. It enables evaluating the unknown while new measurements are added to the network and measurements with gross errors are deleted [3, 4]. In the article, a complementary recurrent equalization is developed. It is original, convenient and recommended for wide application in production.
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Sato, Ryuta, and Kotaro Nagaoka. "Motion Trajectory Measurement of NC Machine Tools Using Accelerometers." International Journal of Automation Technology 5, no. 3 (May 5, 2011): 387–94. http://dx.doi.org/10.20965/ijat.2011.p0387.
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NC controllers use different types of compensation systems to improve motion accuracy of feed drive systems against pitch error, friction, backlash, and elastic deformation. Compensators for static error, such as pitch and squareness errors, are tuned semiautomatically. However, for dynamic error such as quadrant glitches and vibration, parameter tuning takes too much time. In this study, motion trajectory measurement for parameter tuning using accelerometers has been proposed. In the methods, displacements of each axis can be obtained from measured accelerations along each axis. Although the obtained displacements include some errors, such as setting error, sensitivity error, and integral error in numerical integration, the errors can be compensated for based on the feedback positions measured simultaneously. To confirm the feasibility of the proposed methods, measurement tests using a grid encoder are carried out. Results of the measurements confirm that the circular trajectories and vibrations can be measured by the proposed method. Automatic parameter tuning method for the backlash compensator is also proposed.
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Miller, Jonathan, Simon Fletcher, Andrew Longstaff, and Simon Parkinson. "Simultaneous Constant Velocity Measurement of the Motion Errors of Linear Axes." International Journal of Automation Technology 14, no. 3 (May 5, 2020): 417–28. http://dx.doi.org/10.20965/ijat.2020.p0417.
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The current standard for machine tool calibration supports the use of quasi-static measurement techniques. When measuring the six degrees of freedom motion errors, the measurements are typically taken consecutively. This introduces uncertainty when comparing the results due to machine deformation during individual measurements. Furthermore, quasi-static measurement techniques are known to be time consuming, a problem that is exacerbated as each degree of freedom must be measured separately. Additionally, the spatial resolution between the selected target positions can have an impact on calibration quality. In the following paper, the benefits of measuring the six motion errors simultaneously while the axis under test is traversing at a nominally constant velocity are presented. Firstly, the motivation for simultaneous continuous capture is presented. Secondly, continuous motion measurements are compared with quasi-static measurements for the six degrees of freedom motion errors showing sub-micrometer and sub-arcsecond correlation. The full effect of a ball screw pitch error is shown which can be missed using traditional quasi-static measurement techniques. Finally, wavelet analysis is performed for further spatial diagnostics along with correlation coefficients calculated to quantify the linear dependency between the six error motions.
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Xing, Chuan, and Hai Zhang. "Optimal Weighted Least Square Data Fusion Method for Redundant IMU Based on Calculation of Measurement Error." Applied Mechanics and Materials 241-244 (December 2012): 149–55. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.149.
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A dodecahedron non-orthogonal redundant IMU configuration was selected as model. To improve fusion accuracy, we proposed an effective calculation method for measurement errors based on the correlation between measurement errors and fusion errors. The method considered the difference between traditional data fusion vector’s projection and measurement results, and then made a conversion from projection error to measurement error. Combined with optimal weighted least square method, measurement error was used to generate an optimal weighted matrix, and this made data fusion errors minimum. Simulations also proved that the fusion result of this method is more accurate than the result of traditional method.
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Lehmann, R., P. von der Gathen, M. Rex, and M. Streibel. "Statistical analysis of the precision of the Match method." Atmospheric Chemistry and Physics 5, no. 10 (October 18, 2005): 2713–27. http://dx.doi.org/10.5194/acp-5-2713-2005.
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Abstract. The Match method quantifies chemical ozone loss in the polar stratosphere. The basic idea consists in calculating the forward trajectory of an air parcel that has been probed by an ozone measurement (e.g., by an ozonesonde or satellite instrument) and finding a second ozone measurement close to this trajectory. Such an event is called a "match". A rate of chemical ozone destruction can be obtained by a statistical analysis of several tens of such match events. Information on the uncertainty of the calculated rate can be inferred from the scatter of the ozone mixing ratio difference (second measurement minus first measurement) associated with individual matches. A standard analysis would assume that the errors of these differences are statistically independent. However, this assumption may be violated because different matches can share a common ozone measurement, so that the errors associated with these match events become statistically dependent. Taking this effect into account, we present an analysis of the uncertainty of the final Match result. It has been applied to Match data from the Arctic winters 1995, 1996, 2000, and 2003. For these ozonesonde Match studies the effect of the error correlation on the uncertainty estimates is rather small: compared to a standard error analysis, the uncertainty estimates increase by 15% on average. However, the effect may be more pronounced for typical satellite Match analyses: for an Antarctic satellite Match study (2003), the uncertainty estimates increase by 60% on average. The analysis showed that the random errors of the ozone measurements and the "net match errors", which result from a displacement of the second ozone measurement of a match from the required position, are of similar magnitude. This demonstrates that the criteria for accepting a match (maximum trajectory duration, match radius, spread of trajectory clusters etc.) ensure that, given the unavoidable ozone-measurement errors, the magnitude of the net match errors is adequate. The estimate of the random errors of the ozonesonde measurements agrees well with laboratory results.
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Vogeser, Michael, and Christoph Seger. "Irregular analytical errors in diagnostic testing – a novel concept." Clinical Chemistry and Laboratory Medicine (CCLM) 56, no. 3 (February 23, 2018): 386–96. http://dx.doi.org/10.1515/cclm-2017-0454.
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AbstractBackground:In laboratory medicine, routine periodic analyses for internal and external quality control measurements interpreted by statistical methods are mandatory for batch clearance. Data analysis of these process-oriented measurements allows for insight into random analytical variation and systematic calibration bias over time. However, in such a setting, any individual sample is not under individual quality control. The quality control measurements act only at the batch level. Quantitative or qualitative data derived for many effects and interferences associated with anindividualdiagnostic sample can compromise any analyte. It is obvious that a process for a quality-control-sample-based approach of quality assurance is not sensitive to such errors.Content:To address the potential causes and nature of such analytical interference in individual samples more systematically, we suggest the introduction of a new term called theirregular(individual)analytical error. Practically, this term can be applied in any analytical assay that is traceable to a reference measurement system. For an individual sample an irregular analytical error is defined as an inaccuracy (which is the deviation from a reference measurement procedure result) of a test result that is so high it cannot be explained by measurement uncertainty of the utilized routine assay operating within the accepted limitations of the associated process quality control measurements.Summary:The deviation can be defined as the linear combination of the process measurement uncertainty and the method bias for the reference measurement system. Such errors should be coinedirregular analytical errorsof the individual sample. The measurement result is compromised either by an irregular effect associated with the individual composition (matrix) of the sample or an individual single sample associated processing error in the analytical process.Outlook:Currently, the availability of reference measurement procedures is still highly limited, but LC-isotope-dilution mass spectrometry methods are increasingly used for pre-market validation of routine diagnostic assays (these tests also involve substantial sets of clinical validation samples). Based on this definition/terminology, we list recognized causes of irregular analytical error as arisk catalogfor clinical chemistry in this article. These issues include reproducible individual analytical errors (e.g. caused by anti-reagent antibodies) and non-reproducible, sporadic errors (e.g. errors due to incorrect pipetting volume due to air bubbles in a sample), which can both lead to inaccurate results and risks for patients.
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Podgors’ky, Kostiantyn, and Sergiy Yepifanov. "Аналіз точності експериментального визначення ККД вентилятора з використанням вимірювачів крутильного моменту." Aerospace Technic and Technology, no. 1 (February 27, 2023): 35–46. http://dx.doi.org/10.32620/aktt.2023.1.04.
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The subject of research in this article is the processes of experimental determination of the characteristics of fans of turbojet bypass engines with a high and ultra-high bypass ratio. The goal is to substantiate the need to use a method based on the determination of torque, and the formation of requirements for the accuracy of its measurement. Tasks: determination of the relationship between measurement errors and the accuracy of determining the efficiency and air flow, analysis of the accuracy of alternative methods for organizing measurements and calculating the indicated parameters, comparative study of these methods, and the formation of recommendations for their practical use. For this, analytical methods of error analysis based on the methods of analysis of random variables are used. The following results were obtained: formulas that relate the errors in the calculation of efficiency and consumption with errors in the measured parameters (mathematical models of errors), and determine requirements to the torque measurement precision, which must determine the efficiency with a specified precision. The scientific and practical novelty of the results obtained is as follows: mathematical models of errors in determining the efficiency and flow in the fan have been formed, which relate the errors in the results of calculations with the errors in the measured parameters; because of the use of these models, experimental methods for determining the characteristics of compressors and fans have been developed; for the first time, an analytical expression was obtained that determines the requirements for the measurement error of torque to experimentally determine the efficiency of fans. It is shown that to determine the efficiency with an accuracy of 0.5 %, the accuracy of torque measurement even in the absence of other measurement errors cannot be worse than 0.5 %, and taking into account the perspective of measuring temperatures and pressures with relative standard deviations σδp = 0.02 % and σδT = 0.25 %, the standard deviation of the torque measurement error should not be more than 0.24 %.
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Zou, Xicong, Xuesen Zhao, Zongwei Wang, Guo Li, Zhenjiang Hu, and Tao Sun. "Error Distribution of a 5-Axis Measuring Machine Based on Sensitivity Analysis of Geometric Errors." Mathematical Problems in Engineering 2020 (February 14, 2020): 1–15. http://dx.doi.org/10.1155/2020/8146975.
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Geometric errors are inevitably introduced into any multiaxis measuring system, and the geometric error is one of the main factors that seriously affects the measurement accuracy. The present work investigates the error distribution of the prototype of a 5-axis measuring machine based on sensitivity analysis of geometric errors. The measurement error modeling of the 5-axis measuring machine is first established via the homogeneous coordinate transformation, and the Sobol global sensitivity analysis method is then employed to quantify the influence of geometric errors on the measurement result with the sensitivity index. The result shows that most of the angular errors are the crucial geometric errors seriously affecting the measurement result. These errors are supposed to be fully considered in the accuracy design and manufacturing stages. The error levels of the crucial geometric errors were distributed and readjusted according to the sensitivity analysis result. Some practical approaches to distribute and improve the crucial geometric errors have been given in detail. The error distribution method is effective to equalize the influence of the crucial geometric errors on the measurement result as possible. The findings of this study provide significant meanings for the optimal design and accurate manufacturing of the 5-axis measuring machine, and the proposed method can be used to improve the measurement accuracy of the 5-axis measuring machine.