• 한국정밀공학회지
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• 제9권4호
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• pp.13-21
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• 1992

Standards concerning the determination of positioning accuracy and repeatability of numerically controlled(NC) machine tools have been published relentlessly over the last 20 years. Since the publication in 1988 of the International Standard 230-2 there has been a pronounced move, both at national and international standards level, to embrace further test procedures for a complete machine tool performance assessment. For example, measurements of angular (pitch, roll, and yaw) and straightness errors along linear axes are now commonplace and complement the existing positioning accuracy and repeatablity tests. More recently the subject of circularity evalutaion has also gained considerable interest. Here dynamic tests, using a kinematic ballbar or circular masterpiece, give an instant overview of the contouring ability of the machine in two axes at specific feedrates. This information is extremely important in optimising machining accuracy. This paper describes moves to complete the machine calibration package in national and international standardis- ation for the assessment of machine tool performance.

• 품질경영학회지
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• 제51권4호
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• pp.619-632
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• 2023

Purpose: The main function of INS (Inertial Navigation System) is to measure the position of an armed vehicle and its performance is confirmed through the positioning accuracy test of Korean Defense Standards (KDS). The current standards, however, do not provide clear test methods and the conditions for performing positioning accuracy tests. Accordingly, the purpose of this study is to develop a new method for positioning accuracy test which would be effective. Methods: In this study, a new INS positioning accuracy test method is suggested based on the analysis of test data collected through a statistical experiment known as central composite design. For the positioning accuracy experiment of K105A1, a self-propelled artillery, two factors of driving velocity and driving distance are considered. Results: Based on the analysis of experimental data, a regression model for the positioning error is fitted and the positioning accuracy test of INS is so developed to maximize the positioning error. The standard proximity rate is used as an additional test criterion to evaluate the performance level of INS. Conclusion: The proposed new positioning accuracy test for INS has the advantage of finding the nonconforming items effectively. It is also expected to be utilized for the other similar INS positioning accuracy tests.

• Progress in Superconductivity
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• 제8권1호
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• pp.40-45
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• 2006

In emergency rooms, patients with acute chest pain should be diagnosed as quickly as possible with higher diagnostic accuracy for an appropriate therapy to the patients with acute coronary syndrome or for avoiding unnecessary hospital admissions. At present, electrocardiography(ECG) and biochemical markers are generally used to detect myocardial infarction and coronary angiography is used as a gold standard to reveal the degree of narrowing of coronary artery. Magnetocardiography(MCG) has been proposed as a novel and non-invasive diagnostic tool fur the detection of cardiac electrical abnormality associated with myocardial ischemia. In this study, we examined whether the MCG can be used fur the detection of coronary artery disease(CAD) in patients, who were admitted to the emergency room with acute chest pain. MCG was recorded from 36 patients admitted to the emergency room with suspected acute coronary syndrome. The MCG recordings were obtained using a 64-channel SQUID MCG system in a magnetically shielded room. In result, presence of CAD could be found with a sensitivity of 88.2 % in patients with acute chest pain without 57 elevation in ECG, demonstrating a possible use in the emergency room to screen CAD patients.

• International Journal of Precision Engineering and Manufacturing
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• 제8권3호
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• pp.20-23
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• 2007

To calibrate precision autocollimators, the Korean Research Institute of Standards and Science (KRISS) has built a small angle generator using a laser interferometer. The system is based on a sine bar mechanism in which the angle is determined from the ratio of two lengths. The rotational angle is measured by the angle interferometer and the heterodyne laser interferometer detects the relative displacement of two retro-reflectors attached to the rotating arm. The distance between the two retro-reflectors of the laser angle interferometer is self-calibrated by an index table positioned on the rotating arm. The resolution of the system is 0.002 seconds, and the accuracy is better than 0.04 seconds within a measuring range of $\pm$1 degree. The small angle generator can also be used with an index table that can divide one circle into 1440 angles. The combined system can generate any angle over 360 degrees to an accuracy of 0.11 seconds.

• 전자공학회논문지A
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• 제30A권5호
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• pp.24-29
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• 1993

The national standards of microwave power in X-band and Ku-band were established using the waveguide microcalorimeters and have been disseminated to the related industries to contribute to industrial development. Through the comparisons and analysis of the measured effective efficiencies for waveguide thermistor mounts in the recent years, the accuracy for maintenance of power standards was confirmed.

• 간호행정학회지
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• 제13권4호
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• pp.462-472
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• 2007

Purpose: Purpose of the this study is to define the hemodialysis noncompliance Indicators and discriminant standards levels for low Flux Hemodialysis patients and development of Hemodialysis noncompliance measurement - brief form. Method: Data was collected from 269 hemodialysis patients. To establish the hemodialysis noncompliance Indicators and to discriminate standards, 13 hemodialysis nurses and 2 nephrology doctors are participated in professional group. To verify the indicators and discriminant standards, data was ananlyzed by the canonical discriminant analysis method using by SAS 8.3 program. Result: 4 Indicators- interdialysis weight gain(IWG); average of recent 4weeks, serum phophate level, skipping of hemodialysis and hemodialysis time shortening without permission- of hemodialysis noncompliance are established and discriminant standards are developed. Discriminant ability of these 4 noncompliance indicators is 99.7%(p=.000). Hemodialysis noncompliance measurement - brief form has 96.3% discriminant accuracy. Conclusion: Hemodialysis noncompliant patients have high risks. It means that special intervention to noncompliance is needed. Also continuous and objective assessment and standards of noncompliance are needed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.953-954
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• 2007

High accurate 20 kA, 6 kA and 2 kA standard current transformers(CTs) with a ratio error within 0.005 % at full rated current have been developed. The CTs are useful as the reference CT of the CT comparator system in the current range of 20 kA to 10 A CT.

• 한국항해항만학회지
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• 제35권8호
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• pp.619-624
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• 2011

Loran(LOang RAnge Navigation) 신호를 이용한 측위 시에 정확도에 가장 큰 영향을 미치는 오차요소는 TOA(Time of Arrival) 측정에서의 ASF(Additional Secondary Factor)이다. 따라서 공항접근이나 항만 접안 등의 측위 정확도를 만족시키려면 먼저 정확한 ASF측정이 선행되어야 하는데, 본 연구에서는 해상에서 ASF를 측정하는 기법을 연구하였다. 그 측정방법으로 포항 Loran-C 주국(9930M)에서 송신하는 로란 신호와 로란 수신기의 기준신호를 세슘원자시계를 기준으로 측정함으로써 해상에서의 ASF를 측정하였고 영일만 해상의 12 곳의 측정지점을 3 km 간격으로 설정하여 측정하였다. 해상측정에서 정확도를 높이기 위해서 전기장 안테나와 자기장 안테나를 동시에 사용하였으며 정확한 위치측정을 위해서 DGPS(Differential GPS)수신기를 이용하였다. 이런 방법을 이용하여 해상에서 ASF를 측정함으로써 ASF 예측값과 비교한 결과를 얻었다.

• 무역학회지
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• 제44권4호
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• pp.87-100
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• 2019

A country's participation in international technical standards development directly relates to its trade competitiveness. Many countries adopt international standards or influence their development process through the ISO/IEC. This study applies the ABCD Model to assess such activities through a constructed ITS index, not only in terms of 'level' of contribution but also in terms of 'process' participation that can give important implications related to the future potential influence of countries in standards development. Having examined seven countries, Korea showed the lowest score implying the need to enhance its performance in both 'international standards adoption' and 'internationalization of domestic standards'. Korea needs to more actively participate in currently on-going standards development processes, establish more offices that improve accuracy in the development, and consider participating in additional committees where domestic interests may potentially be at stake. Although KATS has improved greatly in regards to its relevant activities and database construction, a more active and specific plan must be made to allow its efforts to successfully influence Korea in international standards development. Confronted with strong challenges from directly competing countries in trade like China and Japan that showed better ITS scores, there is a need for Korea to step up its research and participation in this field.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.683-684
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• 2008

The resistance is frequency dependent by the Seeback effect, loading effect, Eddy current loss, uniformly distributed inductance of the resistance element and uniformly distributed self-capacitance of the resistance element and capacitance between resistance element and it's box. A precise ac resistance measurement system has been developed for using as maintaining and dissemination of national ac resistance standards. The developed resistance measurement system can be used as a instrument of national ac resistance standards at frequency less than 10 kHz and it's measurement accuracy was 0.23(${\mu}{\Omega}/{\Omega}$)+4.2 ${\mu}{\Omega}$ at 1592 Hz and 20 V.