• 대한치과의사협회지
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• 제57권8호
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• pp.448-455
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• 2019

This study aims to apply the Generalizability Theory (G-theory) for estimation of reliability of evaluation scores between raters on Patient Dentist Interaction. Selecting a number of raters as multiple error sources, this study was analyzed the error sources caused by relative magnitude of error variances of interaction between the factors and proceeded with D-study based on the results of G-study for optimal determination of measurement condition. The estimated outcomes of variance component for accuracy among the Patient Dentist Interaction evaluation with G-theory showed that impact of error was the biggest influence factor in students. The second influence was the item effect, and the rater effect was relatively small. The Generalizability coefficients for case1 and case2 which were estimated through the D- study were calculated relatively low.

• 반도체디스플레이기술학회지
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• 제3권4호
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• pp.19-27
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• 2004

The characteristic evaluation of A/D converter is to measure the linearity of the converter. The evaluation of the linearity is to measure the DNL, INL, gain error and offset error in the various test parameters of A/D converter. Generally, DNL and INL are to be measured by the Histogram Test Algorithm in the DSP-based ATE environment. And gain error and offset error are to be measured by the calculation equation of the measuring algorithm. It is to propose the new Concurrent Histogram Test Algorithm for the test of the housekeeping A/D converter used in the CDMA cellular phone. Using the proposed method, it is to measure the DNL, INL, gain error and offset error concurrently and to show the measured results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권2호
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• pp.66-70
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• 2005

Linearity of ratio error of instrument transformer comparator has been tested using wide ratio error voltage transformer(VT) with the ratio errors in the range of -3 ％ to 3 ％. The technique is the method for evaluation of the linearity for instrument transformer comparator by comparing both the theoretical and experimental values in wide ratio error VT. The developed method has been successfully applied for calibration and correction in instrument transformer comparator belonging to industry.

• 대한공간정보학회지
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• 제24권2호
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• pp.79-87
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• 2016

As 3D geospatial information is demanded, terrestrial laser scanners which can obtain 3D model of objects have been applied in various fields such as Building Information Modeling (BIM), structural analysis, and disaster management. To acquire precise data, performance evaluation of a terrestrial laser scanner must be conducted. While existing 3D surveying equipment like a total station has a standard method for performance evaluation, a terrestrial laser scanner evaluation technique for users is not established. This paper categorizes and analyzes error sources which generally occur in terrestrial laser scanning. In addition to the prior researches about categorizing error sources of terrestrial Laser scanning, this paper evaluates the error sources by the actual field tests for the smooth in-situ applications.The error factors in terrestrial laser scanning are categorized into interior error caused by mechanical errors in a terrestrial laser scanner and exterior errors affected by scanning geometry and target property. Each error sources were evaluated by simulation and actual experiments. The 3D coordinates of observed target can be distortedby the biases in distance and rotation measurement in scanning system. In particular, the exterior factors caused significant geometric errors in observed point cloud. The noise points can be generated by steep incidence angle, mixed-pixel and crosstalk. In using terrestrial laser scanner, elaborate scanning plan and proper post processing are required to obtain valid and accurate 3D spatial information.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권6호
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• pp.274-278
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• 2005

Voltage transformer(VT) comparison measurement system is usually used for measurements of ratio error and phase angle error of VT made in industry. Both ratio error and phase angle error in VT are critically influenced by values of burden of VT used. External burden effects on both ratio error and phase angle error in VT are theoretically calculated. From the theoretical calculation, a method of evaluation for linearity of ratio error and phase angle error in VT measurement system have been developed using the standard capacitive burdens, with negligible dissipation factor less than 10$^{-4}$. These burden consists of five standard capacitors, with nominal capacitance of 1.1 $\mu$F, 1 $\mu$F, 0.1 $\mu$F, 0.01 $\mu$F, 0.001 $\mu$F. The developed method has been applied in VT measurement system of industry, showing in good consistency and linearity within 0.001 $\%$ between theoretical and measured values.

• 한국운동역학회지
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• 제14권3호
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• pp.49-65
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• 2004

The purpose of this study is development of posture evaluation and Range of Motion(ROM) system by using digital vision analysis method. The results of this study are as follows. First, Scoliosis evaluation through this research measurement system represent 3mm error in 7 cervical point and deepest lumbar point, 0.7mm error in other point. This mean this research measurement system have a reliability for scoliosis evaluation. Second, for spine line evaluation on high fat subject, we need reconstrection spine line after measurement for fat thickness in 7 cervical point and deepest lumbar point. Third, In pedioscope error test, it present 0.01848cm in X axis and 0.01757cm in Y axis. This results mean pedioscope have a reliability foot evaluation. Forth, Posture evaluation and Range of Motion measurement system by using digital vision analysis method can fast measure in range of motion and foot evaluation and posture. therefore we can expect this system application in young people posture clinic center and hospital and so on.

• 전기학회논문지
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• 제56권5호
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• pp.926-932
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• 2007

A recently developed methods for on-site calibration of the current transformer (CT) comparator system have been reviewed in the paper. The method utilizes several traveling standards, which consist of the CT, non-reactive standard resistors, wide ratio error CT, and shunt resistors. The traveling CT is used for absolute evaluation of a standard CT belonging to industry. The non-reactive standard resistors and a wide ratio error CT are used for the linearity check of errors in the current comparator. The shunt resistors are used for evaluation of CT burden of industry.

• 전기학회논문지P
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• 제57권4호
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• pp.437-443
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• 2008

We have developed an evaluation technique for both ratio error and phase displacement of current transformer (CT) comparator by using the precise standard capacitors and resistors. By applying this technique to equivalent circuit of CT comparator evaluation system, we can obtain the calculated and measured ratio errors (or phase displacements) in the CT comparator. Thus we can evaluate ratio errors and phase displacement of CT comparator by comparing the calculated and measured ratio errors (or phase displacements). The method was applied to CT comparator under test with the ratio errors and phase displacement ranges of $0{\sim}{\pm}10%$ and $0{\sim}{\pm}7.5$ crad, respectively. Finally we have compared the ratio error and phase displacement of the CT comparator obtained in this method with specifications of two companies.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권11호
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• pp.503-507
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• 2005

Both ratio error and phase angle error in voltage transformer(VT) depend on values of VT burden used. Thus, precise measurement of burden is very important for the evaluation of VT. A method of evaluation for VT burden has been developed by employing the portable decade resistor, with AC-DC resistance difference less than 10-3. The burden value(value and power factor) can be obtained by conductance and susceptance, obtained by measuring the change of ratio error and phase angle error caused by the resistance change of decade resistor. The burden value and power factor obtained by the method are consistent with those obtained using power analyzer within corresponding uncertainties.

• International Journal of Reliability and Applications
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• 제11권2호
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• pp.123-138
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• 2010

This paper investigates a mathematical model of a system composed of two non-identical unit parallel system with common-cause failure, critical human error, non-critical human error, preventive maintenance and two type of repair, i.e. cheaper and costlier. This system goes for preventive maintenance at random epochs. We assume that the failure, repair and maintenance times are independent random variables. The failure rates, repair rates and preventive maintenance rate are constant for each unit. The system is analyzed by using the graphical evaluation and review technique (GERT) to obtain various related measures and we study the effect of the preventive maintenance preventive maintenance on the system performance. Certain important results have been derived as special cases. The plots for the mean time to system failure and the steady-state availability A(${\infty}$) of the system are drawn for different parametric values.