• Particle and aerosol research
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• v.5 no.2
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• pp.53-62
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• 2009

In this study, the continuous monitoring of the concentration of PM-10 atmospheric particulate matter using beta ray attenuation method was compared with gravimetric method from September, 2006 to August, 2007. On the effects of the PM-10 concentration and mass difference by relative humidity and precipitation were considered. The result showed that the measurement error between beta ray method and gravimetric method are within -3~6% in average, which means PM-10 concentration data with beta ray method are relatively comparable. The current study also shows that the high PM-10 concentration events are mainly due to haze, Asian dust, and high relative humidity and the PM-10 mass concentration is closely related with relative humidity and precipitation events. Based on daily mean data, the PM-10 increases as relative humidity increases up to 70~80%, then decreases over 80% due to the precipitation. However, the distinct measurement discrepancy was not shown between beta ray method and gravimetric method based on current results. Consequently, this study shows that the collocated measurement in different instrument is essential in order to quantify the accuracy of PM-10. Furthermore, the more comprehensive and spatially distributed comparison is needed and this is remained for future study.

• Journal of Veterinary Clinics
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• v.28 no.1
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• pp.108-112
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• 2011

In clinical settings, researchers often want to assess agreement between two measurements (or tests) of the same continuous variable. For example, when new point-of-care analyzer for testing blood glucose level were introduced clinicians need to compare results from standard or established laboratory method of measurement to those of new or point-of-care analyzer. The question in a method-comparison study would either of two different methods be used to measure the same variable equivalently. In this paper common misuse of statistical methodologies seen in the medical literatures such as correlation coefficient and paired t-test are discussed. The Bland-Altman technique has been widely used for this purpose and provides a graphic in presentation of the findings from a method-comparison study, with a mean value of measurement, this bias and the limits of agreement. For ease of application and interpretation of this technique we discussed the analysis procedure and illustrated with two worked examples. Finally, a number of alternative ways in which data can be analysed and reported in such studies were reviewed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.12
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• pp.1260-1268
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• 2009

Three methods(the stepped sine method, the statistical method(random excitation method) and the maximum-length sequence(MLS) method) for head-related transfer functions(HRTFs) are experimentally compared in view point of accuracy and efficiency. First, the stepped sine method has high signal-to-noise ratio, but low efficiency. Second, the statistical method is fast measurement speed, but weak to noise than the other methods. Finally, the MLS method shows both good efficiency and high signal-to-noise ratio, but it needs additional software or equipment such as MLS signal generator. For comparison of measurement accuracy, HRTFs of KEMAR dummy are measured for various azimuths and elevations. Error norms for magnitude and phase of HRTFs are defined and calculated for the measured HRTFs. The calculated error norms show that the methods give similar results in magnitude and phase except a little phase difference in the MLS method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.700-703
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• 2003

The test method of ASTM E 756 and KS D 0076 to estimate vibration-damping properties is compared. Comparison method depending on specimen support, exciting method and calculation method for loss factor is used. Half-power bandwidth method and vibration decay method is used in the calculation method for loss factor, and Young's modulus is decided by geometric character and density for specimen and resonance frequency. Vibration measurement sensor is compared by using non-contact displacement detector, velocity detector and accelerometer. This paper is also presented the matter which is able to cause error in the measurement

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1466-1472
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• 2018

A key comparison has been made between the air-kerma standards of the National Institute of Metrology (NIM), China, and other Asia Pacific Metrology Programme (APMP) members in the medium-energy X-ray. This paper reviews the primary standard Free-air ionization chamber correction factor experimental method and Monte Carlo simulation method in the NIM. The experimental method and the Monte Carlo simulation method are adopted to obtain the correction factor for the medium-energy X-ray primary standard free-air ionization chamber at 100 kV, 135 kV, 180 kV, 250 kV four CCRI reference qualities. The correction factor has already been submitted to the APMP as key comparison data and the results are in good agreement with those obtained in previous studies. This study shows that the experimental method and the EGSnrc simulation method are usually used in the measurement of the correction factor. In particular, the application of the simulation methods is more common.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.519-524
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• 1998

Formaldehyde is known to have adverse health effects, and is also found to be a product of atmospheric. photochemical reaction%. Several methods have been employed for the measurement of formaldehyde. Among them, two common methods are comparatively evaluated in this study, i.e. the chromotropic acid method and the HPLC method coupled with 2,4- dinitrophenylhydrazine (DNPH) derivatization of carbonyl compounds. Method evaluation and validation were performed with respect to repeatability, linearity, collection efficiency, and recovery efficiency. Comparison of formaldehyde concentrations measured simultaneously in the field using the two (n=20) and 35.8%, respectively. Overall, the measured levels by chromotropic acid method appeared to ice significantly higher than those by DNPH-HPLC method, indicating a positive interference due to the other aldehydes collected together with formaldehyde.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.2
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• pp.130-137
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• 2016

Non-destructive testing methods for composite materials (e.g., carbon fiber-reinforced and glass fiber-reinforced plastic) have been widely used to detect damage in the overall industry. This study detects defects using optical infrared thermography. The transient heat transport in a solid body is characterized by two dynamic quantities, namely, thermal diffusivity and thermal effusivity. The first quantity describes the speed with thermal energy diffuses through a material, whereas the second one represents a type of thermal inertia. The defect detection rate is increased by utilizing a lock-in method and performing a comparison of the defect detection rates. The comparison is conducted by dividing the irradiation method into reflection and transmission methods and the irradiation time into 50 mHz and 100 mHz. The experimental results show that detecting defects at 50 mHz is easy using the transmission method. This result implies that low-frequency thermal waves penetrate a material deeper than the high-frequency waves.

• The Journal of Korean Physical Therapy
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• v.34 no.6
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• pp.283-291
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• 2022

Purpose: The purpose of this study was to compare and analyze the method of measuring the angle of the trunk rotation using a smartphone with 3D smartphone holder compared to a scoliometer, which is a measuring tool used as a method for diagnosing scoliosis in scoliosis patients. Methods: Angle of trunk rotation was measured in 21 subjects diagnosed with scoliosis. scoliometer measurement method, a smartphone measurement method with a 3D smartphone holder, a smartphone blind measurement method with a 3D smartphone holder, a smartphone measurement method without a smartphone holder, a smartphone blind measurement method without a smartphone holder, and a total of five measurement methods were repeated three times for comparison and analysis. Results: The smartphone measurement method with a 3D smartphone holder has excellent intra-rater reliability of angle of trunk rotation (Rater A; ICC3, 2≥0.993, Rater B; ICC3, 2≥0.992). The smartphone blind measurement method with a 3D smartphone holder has excellent inter-rater reliability of angle of trunk rotation (ICC2, 2≥0.968). The scoliometer measurement method had the highest validity (r=0.976) with the smartphone measurement method with a 3D smartphone holder, and the blind measurement method without a smartphone holder had the lowest validity (r=0.886). Conclusion: These findings, the angle of trunk rotation measured by the smartphone measurement method with a 3D smartphone holder in scoliosis patients showed high reliability and validity compared to the scoliometer measurement method.

• Transactions of Materials Processing
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• v.5 no.4
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• pp.343-352
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• 1996

One of the preferred methods that can be used to verify the results of finite element analysis is to measure surface strains of the deformed part for purpose of direct comparison with simulation results. Instead of using the usual manual method the vision-based measurement method is capable of determining surface geometry and strain from the deformed grid pattern automatically with the help of a computer. To obtain strain distribution over an area, the coordinates of such a surface grid are determined from the multiple video images by applying the photogrammetry principle. Methods to improve the overall accuracy of the vision-based strain measurement system are explored and the possible accuracies that can be attained by such a measurement method are discussed. A major emphasis is placed on the initial grid application method its accuracy and ease of subsequent image processing. Finite element analyses of limiting dome height(LDH) test are carried out and the results of them are compared with exsperimen-tal data.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.12
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• pp.1176-1181
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• 2010

This paper proposes three positioning algorithms using TOA measurements: 1) The well-known linearization method using Taylor series, 2) a modified Savarese method considering measurement noise, which does not need linearization, and 3) a modified Bancroft method where TOA measurements instead of pseudorange measurements are considered. Furthermore, through an error analysis, for Savarese method, divergence of altitude is anticipated if the transmitters are located at the same height. To prevent height divergence, the Savarese method is modified again for receivers which assumed moving on the even plane. Error analysis also shows the relationship between Bancroft and Savarese method. From the analysis it is expected that the performance of Savarese method is worse than Bancroft method because of error amplification during difference operation. Experiments using real TOA measurement from the time difference of ultra sound and RF validate the proposed methods and show that analysis is correct.