• IEIE Transactions on Smart Processing and Computing
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• 제3권4호
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• pp.205-211
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• 2014

This paper reports an efficient algorithm for accurate rolling shutter distortion removal. A hierarchical global motion estimation approach for a group of blocks reduces the level of computation by three orders of magnitude. In addition, the motion of each scanline is determined accurately by averaging two candidates obtained through cubic spline interpolation. The experimental results show that the proposed method produces accurate motion information with significant computation reduction and corrects the rolling shutter distortion effectively.

• 한국통신학회논문지
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• 제40권12호
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• pp.2343-2352
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• 2015

본 논문에서는 U-시차 지도(U-disparity map)와 정방향-역방향 에러 제거를 통하여 자동차 환경에서의 새로운 모션 필드 예측기법을 제안한다. 일반적으로 자동차에 장착된 카메라로 획득된 영상에서는 자동차의 움직임에 따라 모션 벡터가 발생하게 된다. 그러나 이러한 모션 벡터는 주변 환경에 영향을 받기 때문에 정확도가 떨어진다. 특히 도로면에서는 인접한 화소값이 유사하기 때문에 정확한 모션 벡터의 추출이 어렵다. 따라서 제안하는 기법에서는 U-시차 지도를 이용하여 도로면을 제거하고 나머지 부분에 대하여 옵티컬 플로우(optical flow)를 수행한다. 또한 모션 벡터의 정확도를 향상시키기 위해 정방향-역방향 에러 제거 방법을 활용한다. 최종적으로 획득한 모션 벡터에 RANSAC(RANdom SAmple Consensus)을 적용하여 차량의 움직임을 예측하고 모션 필드를 생성한다. 실험을 통해 제안하는 기법이 기존의 기법보다 성능이 우수한 것을 확인하였다.

• 한국치위생학회지
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• 제18권3호
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• pp.269-280
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• 2018

Objectives: The purpose of this study was to investigate the change in the posture of dental hygiene students and clinical dental hygienists when implementing dental scaling before and after posture correction training using the rapid upper limb assessment (RULA) method and 3D motion analysis. Methods: Thirty-two healthy volunteers performed dental scaling to remove artificial calculus on dental manikin. The movement and angle of the joints were verified by RULA and 3D motion analysis during the procedure. The subjects were also photographed for 1 minute during the procedure for 10 minutes while the calculus was removed. After the removal of the calculus, the subject and the instructor checked the video together. Posture correction training was conducted by the instructor so that the subject could perform the calculus removal operation in the correct posture. Artificial calculus of the adjacent teeth was then removed for the same period of time, and the change in posture was reviewed. Results: The total score of the posture change using RULA was $5.72{\pm}0.58$ before training and $4.31{\pm}0.10$ after training, showing a significant decrease after training (p<0.001), and upper arm, lower arm, wrist position, neck and waist position showed significant decrease after training. The three-dimensional motion analysis showed significant differences according to the criteria measured at all measurement sites except the left shoulder (p<0.05) Conclusions: It was confirmed through RULA and 3D motion analysis that postural correction training using calculus removal images was effective, and that correct postural education is essential to preventing musculoskeletal diseases caused by removal of calculus.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.428-435
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• 2017

In this paper, we propose a novel motion field estimation algorithm for which a U-disparity map and forward-and-backward error removal are applied in a vehicular environment. Generally, a motion exists in an image obtained by a camera attached to a vehicle by vehicle movement; however, the obtained motion vector is inaccurate because of the surrounding environmental factors such as the illumination changes and vehicles shaking. It is, therefore, difficult to extract an accurate motion vector, especially on the road surface, due to the similarity of the adjacent-pixel values; therefore, the proposed algorithm first removes the road surface region in the obtained image by using a U-disparity map, and uses then the optical flow that represents the motion vector of the object in the remaining part of the image. The algorithm also uses a forward-backward error-removal technique to improve the motion-vector accuracy and a vehicle's movement is predicted through the application of the RANSAC (RANdom SAmple Consensus) to the previously obtained motion vectors, resulting in the generation of a motion field. Through experiment results, we show that the performance of the proposed algorithm is superior to that of an existing algorithm.

• 대한족부족관절학회지
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• 제14권2호
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• pp.146-150
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• 2010

Purpose: Pilon fracture has several serious complications such as joint stiffness, arthrosis and delayed angular deformity. We report short-term results of new treatment modality using distracted dynamic external fixators and early controlled ankle motion. Materials and Methods: Eight cases of severe pilon fractures for which we tried small plate fixation and additional distracted dynamic external fixators from July 2007 to June 2009 were included. Half passive continuous ankle joint motion was allowed under free hinged ring fixators after the operation. The external fixators were removed after two or three months from the surgery. We investigated joint space by radiograph, joint pain, range of motion, patient's satisfaction of treatment protocol. Results: Joints were distracted when external fixators were applied and mean 28% of space loss developed after removal of external fixators. In most of cases, satisfactory alignments were maintained. Regarding range of joint motion, mean dorsiflexion angle was 15 degrees and mean plantarflexion angle was 32 degree in the condition of wearing external fixators. There was mean 8% reduction of range of motion but no further progression of ankle stiffness after removal of external fixators. Dorsiflexion was not improved after that, but plantarflexion angle was improved 10% even after removal of external fixators. Patients were generally in compliance with the treatment protocols with high level of satisfaction. Conclusion: We got good results with distracted dynamic external fixators and early continuous half-passive joint motion for pilon fractures in terms of joint pain and range of motion. Therefore we suggest this new protocol as an alternative modality for severe pilon fractures.

• Journal of Korean Neurosurgical Society
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• 제55권2호
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• pp.73-77
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• 2014

Objective : The purpose of this study was to evaluate the efficacy of implant removal of percutaneous short segment fixation after vertebral fracture consolidation in terms of motion preservation. Methods : Between May 2007 and January 2011, 44 patients underwent percutaneous short segment screw fixation due to a thoracolumbar burst fracture. Sixteen of these patients, who underwent implant removal 12 months after screw fixation, were enrolled in this study. Motor power was intact in all patients, despite significant vertebral height loss and canal compromise. The patients were divided into two groups by degree of osteoporosis : Group A (n=8), the non-osteoporotic group, and Group B (n=8), the osteoporotic group. Imaging and clinical findings including vertebral height loss, kyphotic angle, range of motion (ROM), and complications were analyzed. Results : Significant pain relief was achieved in both groups at final follow-up versus preoperative values. In terms of vertebral height loss, both groups showed significant improvement at 12 months after screw fixation and restored vertebral height was maintained to final follow-up in spite of some correction loss. ROM (measured using Cobb's method) in flexion and extension in Group A was $10.5^{\circ}$ ($19.5/9.0^{\circ}$) at last follow-up, and in Group B was $10.2^{\circ}$ ($18.8/8.6^{\circ}$) at last follow-up. Both groups showed marked improvement in ROM as compared with the screw fixation state, which was considered motionless. Conclusion : Removal of percutaneous implants after vertebral fracture consolidation can be an effective treatment to preserve motion regardless of osteoporosis for thoracolumbar burst fractures.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.664-667
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• 2008

Since the advent of pedicle screw fixation system, posterior spinal fusion has markedly increased This intemal fixation system has been reported to enhance the fusion rates, thereby becoming very popular procedure in posterior spinal arthrodesis. Although some previous studies have shown the complications of spinal instruments removal, i.e. loss of correction and spinal collapse in scoliosis or long spine fusion patients, there has been no study describing the benefit or complications in lumbar spinal fusion surgery of one or two level. In order to clarify the effect of removal of instruments on mechanical motion profile, we simulated a finite element model of instrumented posterolateral fused lumbar spine model, and investigated the change of mechanical motion profiles after the removal of instrumentation.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1998년도 Proceedings of International Workshop on Advanced Image Technology
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• pp.16.2-21
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• 1998

Old movies are often corrupted by randomly located blotches and scratches. In this paper were present an efficient method for detection and removal of these distortions. The presented method is composed of two separate steps: the detection process and the restoration process. In the detection process, blotch locations are detected through global motion segmentation, the sequential approach to motion segmentation, a robust model-fit criterion and so on, we form the algorithm for the algorithm for the global motion segmentation tuned to the blotch detection problem. In the restoration process, the missing data of the detected blotch areas are temporally extrapolated from the corresponding image areas at the preceding or the succeeding image frame with considering the global motion segmentation results. We apply the presented method to moving image sequences distorted by artificial blotches. The method works very well and provides a subjective improvement of picture quality.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.922-927
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• 2003

In this paper, slurry fluid motion, abrasive particle motion, and roles of groove patterns on the pads are numerically investigated in the 2D and 3D geometries. The simulation results are analyzed in terms of experimental removal rate and WIWNU (within wafer non-uniformity) for ILD (inter level dielectric) CMP process. Numerical investigations reveal that the grooves in the pad behave as uniform distributor of abrasive particles and enhance the removal rate by increasing shear stress. Higher removal rate and desirable uniformity are numerically and experimentally observed at the pad with grooves. Numerical analysis is very well matched with experimental results and helpful for understanding polishing mechanism and local physics.

• 대한기계학회논문집B
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• 제29권4호
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• pp.435-440
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• 2005

In this paper, slurry fluid motion, abrasive particle motion, and roles of groove patterns on the pads are numerically investigated in the 2D and 3D geometries. The simulation results are analyzed in terms of experimental removal rate and WIWNU (Within Wafer Non-Uniformity) for ILD (Inter Level Dielectric) CMP process. Numerical investigations reveal that the grooves in the pad behave as uniform distributor of abrasive particles and enhance the removal rate by increasing shear stress. Higher removal rate and desirable uniformity are numerically and experimentally observed at the pad with grooves. Numerical analysis is very well matched with experimental results and helpful fur understanding polishing mechanism and local physics.