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Radiation Detection and Measurement
Published in Shaheen A. Dewji, Nolan E. Hertel, Advanced Radiation Protection Dosimetry, 2019
The determination of measurement uncertainty is an essential part of measurement quality assurance. The types of uncertainty components include: Type A, or uncertainties that can be evaluated using statistical means, and Type B, referring those uncertainties evaluated by other means. Previously, these two types were also referred to as random, and systematic, respectively. The usual approach to the evaluation of Type A uncertainties is to calculate the standard deviation of the mean, σmean, of a series of independent measurements. It is often assumed that the original distribution is a normal distribution. The larger the sample size, the smaller the standard error of the mean.
Uncertainty Analysis
Published in Patrick F. Dunn, Fundamentals of Sensors for Engineering and Science, 2019
The terms uncertainty and error each have different meanings in modeling and experimental uncertainty analysis. Modeling uncertainty is defined as a potential deficiency due to a lack of knowledge and modeling error as a recognizable deficiency not due to a lack of knowledge [7]. According to Kline [9], measurement error is a specific value defined as the difference between the true value and the measured value. It is a specific value. Measurement uncertainty is an estimate of the error in a measurement. It represents a range of possible values that the error might assume for a specific measurement. Additional uncertainty can arise because of a lack of knowledge of a specific measurand value within an interval of possible values, as described in Section 13.12.
Advanced Concepts
Published in Kim H. Pries, Jon M. Quigley, Testing Complex and Embedded Systems, 2018
Measurement uncertainty is related to systematic and random error of measurements and relies on the accuracy (the value of the mean) and the precision (the value of the variance) of the instrument used for the measurement. Intuitively, the poorer the mean and variance values, the larger the measurement uncertainty will be.
Toward a simplified calibration method for 23 nm automotive particle counters using atomized inorganic salt particles
Published in Aerosol Science and Technology, 2023
H. Krasa, M. Kupper, M. A. Schriefl, A. Bergmann
The measurement uncertainty was calculated according to The Guide to the expression of uncertainty in measurement (GUM) (JCGM. 2008). Uncertainty contributors were the reference CPC including the flow rate variation (± 10% according to the manual), the test CPC (± 5.6% according to the ISO 17025 calibration certificate), splitter bias correction factor (± 2%) and statistical variance (between ± 0.1% to 2% depending on the counted PN concentration). This leads to uncertainties of 13% − 14% of the measured CE. Uncertainties were not plotted to avoid overloading in the plots. Size distributions and CE measurements were repeated several times, daily variations of the CE for repeated measurements were typically within 5%. The sizing accuracy of the DMA is ± 1% at 100 nm according to the device manual.
Performance enhancement of photovoltaic module using a sun tracker with side reflectors (STSR system)
Published in International Journal of Green Energy, 2023
Amirhosein Ekbatani, Behnam Mostajeran Goortani, Moein Karbalaei
Experiments were performed in November and December and data collection was done every fifteen minutes. Data include maximum power point current (Impp), maximum power point voltage (Vmpp) and maximum power point (Pmpp) by PV analyzer, module received radiation by solar power meter and module temperature by digital thermometer. The measurement accuracy and uncertainty of the instruments used in the experiments are given in Table 2. The measurement uncertainty is calculated using the relationships presented in (Chimeno, Gonzalez, and Castro 2005). To compare and evaluate the effect of using the STSR system on the output of the photovoltaic module, another completely similar module in the same condition (tilt angle and azimuth angle) has been used and data sampling has been done from both modules simultaneously.
Experimental Study of the Effect of Different Air Gap Orientations on Performance of Fire Protective Clothing
Published in Heat Transfer Engineering, 2023
Bhavna Rajput, Tarun Kumar, Bahni Ray, Apurba Das, Prabal Talukdar
In the present work, variation of temperature rise with time is calculated. The main source of error in the measurement is due to systematic uncertainty (instrument uncertainty) and precision uncertainty (measurement uncertainty). The setup used in the present work uses the thermocouple for the temperature measurement. The systematic uncertainty in the present study includes both uncertainty due to the thermocouple material (0.5%) and uncertainty obtained due to copper calorimeter sensor (0.0419%). Uncertainty obtained due to copper calorimeter sensor was the uncertainty determined after the thermocouple is incorporated on the copper plate and it was calculated by comparing the sensor temperature with the IR gun readings.