• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1793-1798
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• 2005

We model the nucleation and motion of defects in the liquid crystal display device with inhomogeneous surface by using fast Q-tensor method, which can calculate scalar order parameter S and nucleation of the defect in the liquid crystal director field. In order to model the defect, homeotropic aligned liquid crystal cell with step inhomogeneous electrode which has a height of $1{\mu}m$ is used. From the simulation, we can observe the nucleation and line of the defect from surface inhomogeneity and the experiment is performed for confirmation.

• Journal of Sensor Science and Technology
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• v.15 no.5
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• pp.328-333
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• 2006

Magnetic Flux Leakage (MFL) methods are widely employed for the nondestructive evaluation (NDE) of gas pipelines. In the application of MFL pipeline inspection technology, corrosion anomalies are detected and identified via their leakage filed due to changes in wall thickness. The gas industry is keenly interested in automating the interpretation process, because a large amount of data to be analyzed is generated for in-line inspection. This paper presents a novel approach to the tasks of data segmentation, feature extraction and depth estimation from gas pipelines. Also, we will show that the proposed method successfully identifying artificial defects.

• Journal of Veterinary Clinics
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• v.14 no.2
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• pp.352-356
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• 1997

5 years Poodle was referred to the Veterinary Teaching Hospital, Chonnam National University in January 1997, with progressive swelling on the rear xiphoid process after cesarean section last year in local-vet clinic. Physical, radiographic, ultrasonographic and intraoperative findings that were obtained from this case were as follow; Physical findings were known as no pain, no fever in the hernia] sal at palpation. Radiographic findings revealed the decreased density of swelling contents more than peritoneum and did not identify the abdominal wall defect line. Ultrasonographic findings showed abdominal wall defect line of 3mm and intra-abdominal originated fat contents with mixed echo(hypoechoic). During the operation, falciform ligament into the hernial sac was observed and not excised, manipulated back into the cavity. The dog was given an herniorraphy with no recurrence and infection.

• Current Optics and Photonics
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• v.3 no.5
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• pp.438-444
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• 2019

In this theoretical study, a line-defect photonic-crystal waveguide hosted in an annular photonic crystal was demonstrated to provide high-performance slow light with a wide band, low group-velocity dispersion, and a large normalized delay-bandwidth product. Combined with structural-parameter optimization and selective optofluid injection, the normalized delay-bandwidth product could be enhanced to a large value of 0.502 with a wide bandwidth of 58.4 nm in the optical-communication window, for a silicon-on-insulator structure. In addition, the group-velocity dispersion is on the order of $10^5$ ($ps^2/km$) in the slow-light region, which could be neglected while keeping the signal transmission unchanged.

• Computers and Concrete
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• v.33 no.5
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• pp.621-630
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• 2024

This study presents novel electromagnetic wave-based methods for evaluating the integrity of cement-based structures using time domain reflectometry (TDR). Two cement-based plates with embedded rebars are prepared under sound and defective conditions. TDR tests are carried out using transmission lines with various numbers of artificial joints, and electromagnetic waves are measured to assess the integrity of the plates. The experimental results show that the travel time of electromagnetic waves is consistently longer in sound plates than in defective ones, and an increase in the reflection coefficients is observed in the defect zone of the defective plates. Electromagnetic wave velocities are higher in the defective plates, especially when connectors are present in the transmission line. A novel approach based on the area of the reflection coefficient provides larger areas in the defective plates, and the attenuation effect of the electromagnetic waves induces a difference in the areas of the reflection coefficient between the two defect conditions. An alternative method using the centroid of the defect zone slightly overestimates the location of the defect zone. The length of the defect zone is estimated using the defect ratio and wave velocities of cement, air, and plate. The length of the defect zone can also be calculated using the travel times within the plate, total measured length of the plate, and wave velocities in the cement and air. Therefore, the electromagnetic wave-based methods proposed in this study may be useful for estimating the location and length of defect zones by considering attenuation effects.

• Journal of Chest Surgery
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• v.10 no.2
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• pp.241-249
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• 1977

Atrial septal defect is one of the most frequently encountered congenital heart disease. Up to December 31, 1976, 1682 cardiac patients received cardiac catheterization in the cardiac department of Yonsei university medical college. Out of the 1682 cardiac patients 723 cases had congenital heart disease and only 116 cases had congetial atrial septal defect. This amounted to 16.04% of all those with congenital heart disease. 58 cases of congenital atrial septal defect operated in the chest surgery department were presented. Of these 58 cases of atrial septal defect, 27 cases were male and 31 cases were female. Their ages ranged from 5 years to 54 years. The systolic pressure of the main pulmonary artery of 40 out of the 58 cases of atrial septal defect was below 40% of that of the systemic blood pressure: in 6 cases, the range of the systolic pressure of the main pulmonary artery was 50-90mmHg; in 12 cases, the range of the systolic pressure of the main pulmonary artery was 40-50mmHg. Average age of these was 30. 1 years. This study tends to show that Korean patients with atrial septal defect even though younger have a slight higher systolic pressure of the main pulmonary artery than Western patients have. The pulmonary blood is 1.5-2.5 times of systemic blood flow in 52 cases out of 58 cases of atrial septal defect.In only one of the 58 cases of atrial septal defect, the Rp was found to be as high as 45% of Rs. All other cases were below this level.51 cases had ostium secundum defect, 4 out of these cases had ostium secundum defect combined with mitral incompetence and 6 out of them had double ostium secundum defect. The remaining 7 cases had ostium primum defect. Their atrial defects were repaired under direct vision utilizing extracorporeal circulation, by hemodilution technic combined with moderate hypothermia. 44 cases [2nd atrial septal defect] were repaired by direct sutures while 14 cases, including the 7 cases ostium primum defects needed patches [1 pericardium and 13 teflon patch]. In 4 cases there were single defects while showed two defects. However the associated septal defect was so small that it could be closed by direct sutures. The size of the defect ranged between 6.0cm2and 10.0cm2 in 19 cases[33.7%]: the smallest being 0. 5cm2 and the largest 24cm2. The surgical mortality was 2 cases [3.4%]. These one case with ostium primum defect, could not be resuscitated on operation table. The cause of death in this case was myocardial failure and MI. The other, a case of ostium primum defect had a second operation on the first operative day due to massive bleeding from LV vent-line insertion site.The patient died on 26th post-operative day due to sepsis.

• Journal of Chest Surgery
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• v.10 no.2
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• pp.230-240
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• 1977

Atrial septal defect is one of the most frequently encountered congenital heart disease. Up to December 31, 1976, 1682 cardiac patients received cardiac catheterization in the cardiac department of Yonsei university medical college. Out of the 1682 cardiac patients 723 cases had congenital heart disease and only 116 cases had congetial atrial septal defect. This amounted to 16.04% of all those with congenital heart disease. 58 cases of congenital atrial septal defect operated in the chest surgery department were presented. Of these 58 cases of atrial septal defect, 27 cases were male and 31 cases were female. Their ages ranged from 5 years to 54 years. The systolic pressure of the main pulmonary artery of 40 out of the 58 cases of atrial septal defect was below 40% of that of the systemic blood pressure: in 6 cases, the range of the systolic pressure of the main pulmonary artery was 50-90mmHg; in 12 cases, the range of the systolic pressure of the main pulmonary artery was 40-50mmHg. Average age of these was 30. 1 years. This study tends to show that Korean patients with atrial septal defect even though younger have a slight higher systolic pressure of the main pulmonary artery than Western patients have. The pulmonary blood is 1.5-2.5 times of systemic blood flow in 52 cases out of 58 cases of atrial septal defect.In only one of the 58 cases of atrial septal defect, the Rp was found to be as high as 45% of Rs. All other cases were below this level.51 cases had ostium secundum defect, 4 out of these cases had ostium secundum defect combined with mitral incompetence and 6 out of them had double ostium secundum defect. The remaining 7 cases had ostium primum defect. Their atrial defects were repaired under direct vision utilizing extracorporeal circulation, by hemodilution technic combined with moderate hypothermia. 44 cases [2nd atrial septal defect] were repaired by direct sutures while 14 cases, including the 7 cases ostium primum defects needed patches [1 pericardium and 13 teflon patch]. In 4 cases there were single defects while showed two defects. However the associated septal defect was so small that it could be closed by direct sutures. The size of the defect ranged between 6.0cm2and 10.0cm2 in 19 cases[33.7%]: the smallest being 0. 5cm2 and the largest 24cm2. The surgical mortality was 2 cases [3.4%]. These one case with ostium primum defect, could not be resuscitated on operation table. The cause of death in this case was myocardial failure and MI. The other, a case of ostium primum defect had a second operation on the first operative day due to massive bleeding from LV vent-line insertion site.The patient died on 26th post-operative day due to sepsis.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.5
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• pp.636-644
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• 2006

Recently, there were some successful examples that the laser welding was introduced into production line. However, the spread of laser welding is not sufficient in many industries. There are several reasons why it is difficult to penetrate the laser welding into production lines. Because it is different from reflection, absorption and permeation of laser beam according to material and surface condition. Moreover, there are significant problems in processing such as absorption and scattering of beam by the induced plasma or plume. Therefore, understanding of mechanism on formation of weld defect in laser welding of the laminated core for motor is very important. In this paper, it was analyzed in terms of materials which was source of defect in laser welding and conventional arc welding. As a results of analysis, insulation coating film of the laminated core was judged to main factor of weld defect. it could be well aware as tracing carbon volume, and it was deduced that weld defect by insulation coating film was caused by difference of mechanism between the two heat sources.

• Journal of Biosystems Engineering
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• v.39 no.2
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• pp.142-149
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• 2014

Purpose: A multispectral algorithm for detection and differentiation of defective (defects on apple skin) and normal Red Delicious apples was developed from analysis of a series of hyperspectral line-scan images. Methods: A fast line-scan hyperspectral imaging system mounted on a conventional apple sorting machine was used to capture hyperspectral images of apples moving approximately 4 apples per second on a conveyor belt. The detection algorithm included an apple segmentation method and a threshold function, and was developed using three wavebands at 676 nm, 714 nm and 779 nm. The algorithm was executed on line-by-line image analysis, simulating online real-time line-scan imaging inspection during fruit processing. Results: The rapid multispectral algorithm detected over 95% of defective apples and 91% of normal apples investigated. Conclusions: The multispectral defect detection algorithm can potentially be used in commercial apple processing lines.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.8
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• pp.761-771
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• 2009

Detecting defects on FPD (Flat Panel Display) color filter before the full panel is made is important to reduce the manufacturing cost. Among many types of defects, the low contrast blemish such as Suzi Mura is difficult to detect using standard CCD cameras. Even skilled inspectors in the inspection line can hardly identify such defects using bare eyes. To overcome this difficulty, point spectrometer has been used to analyze the spectrum to differentiate such defects from normal color filters. However, scanning ever increasing-size color filters by a point spectrometer takes too long time to be used in real production line. We propose a system using a spectral camera which can be viewed as a line scan camera composed of an array of point spectrometers. Three types of lighting system that exhibit different illumination spectrums are devised together with a calibration method of the proposed spectral camera system. To visualize the defect areas, various processing algorithms to identify and to enhance the small differences in spectrum between defective and normal areas are developed. Experiments shows 85% successful visualization. of real samples using the proposed system.