• 치과방사선
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• 제28권2호
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• pp.471-489
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• 1998

For the successful endodontic treatment, root canal should be cleaned thoroughly by accurate mechanical and chemical canal preparation and sealed completely with canal filling material without damaging the periapical tissues. The accuracy of the root canal length measurement is a prerequisite for the success of the endodontic treatment, and the root canal length is often determined by the standard periapical radiographs and digital tactile sense. In this study, the accuracy and the clinical usefulness of Digora/sup (R)/, an intraoral digital imaging processor and the conventional standard radiographs were compared by measuring the length from the top of the file to the root apex. 30 single rooted premolars were invested in a uniformly sized blocks and No.25 K-file was inserted into and fixed in each canal. Each block was placed in equal distance and position to satisfy the principle of the bisecting angle and paralleling techniques and Digora/sup (R)/ system's image and standard periapical radiographs were taken. Each radiograph was examined by 3 different observers by measuring the length from top of the file to the root apex and each data was compared and analyzed. The results were as follows; 1. In the bisecting angle technique, the average difference between the Digora/sup (R)/ system and standard periapical radiograph was 0.002 mm and the standard deviation was 0.341 mm which showed no statistically significant difference between the two systems(p>0.05). Also, in the paralleling technique, the average difference between these two system was 0.007 mm and the standard deviation was 0.323 mm which showed no statistically significant difference between the two systems(p>0.05). 2. In Digora/sup (R)/ system, the average difference between the bisecting angle and paralleling technique was -0.336 mm and the standard deviation was 0.472 mm which showed a statistically significant difference between the two techniques(p<0.05). Also, in the standard periapical radiographs, the average difference between the bisecting angle and paralleling technique was 0.328 mm and the standard deviation was 0.517 mm which showed a statistically significant difference between these two techniques(p<0.05). 3. In Digora/sup (R)/ system and the standard periapical radiographs. there was a statistically significant difference between the measurement using the bisecting angle technique and the actual length(p<0.05), But there was no statistically significant difference between the measurement using the paralleling technique and the actuallength(p>0.05). In conclusion. the determination of the root canal length by using the Digora/sup (R)/ system can give us as good an image as the standard periapical radiograph and using the paralleling technique instead of the bisecting angle technique can give a measurement closer to the actual canal length. thereby contributing to a successful result. Also. considering the advantages of the digital imaging processor such as decreasing the amount of exposure to the patient. immediate use of the image. magnification of image size. control of the contrast and brightness and the ability of storing the image can give us good reason to replace the standard periapical radiographs.

• 대한방사선기술학회지:방사선기술과학
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• 제43권1호
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• pp.15-21
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• 2020

This study was purpose to evaluation of Modulation Transfer Function in Measurements by using the International electrotechnical commission standard(IEC 62220-1) which were edge device each angle by using edge method. In this study was Aero(Konica, Japan) image receptor which is a indirect Flat panel detector(FPD) was used. The size of matrix 1994 × 2430 (14"× 17" inch) which performed 12 bit processing and pixel pitch is 175 ㎛. The results of shown as MTF measurements at IEC standard. The amount of data seemed reasonable and at an MTF value of 0.1 the spatial frequencies were 2.56 cycles/mm at an angle of 2.4°. MTF value of 0.5 the spatial frequencies were 1.32 cycles/mm at an angle of 2.4°. This study were to evaluate MTF by setting each angle 2.0°~2.8° degrees the most effective optimal edge angle and to suggest the quantitative methods of measuring by using IEC.

• 한국결정학회지
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• 제6권2호
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• pp.88-92
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• 1995

X-선을 이용한 초정밀 측정은 길이, 각도, 결정구조해석 등 많은 분야에서 응용되고 있다. 본 논문은 실리콘 결정을 이용한 초정밀 각도측정에 대한 결과이다. 실리콘 단결정 내부의 여섯 개의 [220] 격자면들은 60°의 사이각(정확도 ∼10-8 rad) 을 이루고 있으므로 육가기둥형의 다면체를 만들어 각도 표준물로 이용하였다. 이러한 각도교정용 실리콘 다면체(silicon polygon)를 사용하여 분해능이 0.36"인 회전엔코더(rotary encoder)의 정확도를 교정하였고, 그 결과를 기존의 회전눈금원판(indexing table)을 사용하여 교정한 결과와 비교하였다.

• 비파괴검사학회지
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• 제4권2호
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• pp.7-14
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• 1985

An experiment to investigate the rate of change of phase angle of eddy current output signal caused by outer surface defect of nonferromagnetic tube by variation of standard depth of penetration and variation of percent of tube wall penetration was carried out. The results of the experiment show that the phase angle of defect signal is increased with decreasing the standard depth of penetration or the depth of defect. The results also show that the phase angle is decreased with increasing the skin effect of eddy current, and that the resolution is decreased with decreasing the depth of defect.

• 한국멀티미디어학회논문지
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• 제23권3호
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• pp.395-401
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• 2020

In this paper, a motion-based ROI extraction algorithm from a high resolution fisheye image is proposed for multi-view monitoring systems. Lately fisheye cameras are widely used because of the wide angle-of-view and they basically provide a lens correction functionality as well as various viewing modes. However, since the distortion-free angle of conventional algorithms is quite narrow due to the severe distortion ratio, there are lots of unintentional dead areas and they require much computation time in finding undistorted coordinates. Thus, the proposed algorithm adopts an image decimation and a motion detection methods, that can extract the undistorted ROI image with a standard angle-of-view for the fast and intelligent surveillance system. In addition, a mesh-type ROI is presented to reduce the lens correction time, so that this independent ROI scheme can parallelize and maximize the processor's utilization.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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• pp.198-203
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• 1998

To acquire the high precision of profile for standard electrode of loss angle, it is needed ultraprecision machining technology like MEAP(Magnetic Electronic Abrasive Polishing) and the very high profile measurement technology which can measure a micro unit about the workpiece. So, in this paper, it was developed the measurement system of precision of profile using non-contactable sensor that was approximate sensor of capacitance type, because that is better than others in the electrical characteristics. And standard electrode of loss angle was machined by the MEAP machining technology. In this study, it was development of precision measurement system. This system could be used measure the workpiece of roundness and straightness much more precise and faster than general mechanical measurement system done before. And it could be helped to minimize machining time and planning by very fast and precise measurement about the workpiece.

• 수산해양기술연구
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• 제58권2호
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• pp.121-129
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• 2022

Density and sound speed contrasts (g and h, respectively), and swimming angle were measured for sandfish (Arctoscopus japonicus) without swimbladder. The density contrast was measured by the volume displacement method while the sound speed contrast was measured by the acoustic measurements of travel time (time-of-flight method). The swimming angle was measured by dividing it into daytime, nighttime, daytime feeding and nighttime feeding. The g was 1.001 to 1.067 with an average (± standard deviation) of 1.032 (± 0.017), and the h was 1.007 to 1.022 with an average (± standard deviation) of 1.015 (± 0.003). The swimming angles (mean ± standard deviation) were 16.8 ± 10.3° during the daytime, 1.9 ± 12.3° during the nighttime, 30.2 ± 12.6° in the daytime feeding and 35.0 ± 13.2° in the nighttime feeding. These results will provide important parameters input to calculate theoretical scattering models for estimating the acoustic target strength of sandfish.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.837-838
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• 2011

• International Journal of Vascular Biomedical Engineering
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• 제1권1호
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• pp.3-12
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• 2003

Ultrasonic pulsed Doppler velocimetry has become a standard international method of classifying carotid disease. Because the measured angle adjusted velocity increases as the Doppler angle increases, examinations should be performed at a convenient standard Doppler examination angle. An angle of 60 degrees is achievable throughout most examinations. Multiple Doppler viewing angles allow the acquisition of velocity vectors during the cardiac cycle, revealing the complex velocity patterns. Ultrasonic velocimetry (whether Doppler or time domain) is based on changes in the phase of the ultrasound echo. Other examinations can be done based on the echo phase. Slow motions of organs such as the brain can be used to monitor changes in edema. Measurements of tissue strain due to the pulsatile filling of the arterioles. This plethysmographic imaging method can display differences in tissue perfusion because of different tissue types and changes in autonomic activity.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권3호
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• pp.137-142
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• 2004

A voltage transformer(VT) used for the estabilishment of high voltage national standard, has generally ratio error and phase angle error. Both errors in VT depend critically on values of external burden of VT used. Both ratio ewer and phase angle error in existence of the external burden is calculated. These calculated values are very well consistent with the experimental result. The principle and the measurement method of VT in our institute are also explained.