• Journal of Institute of Control, Robotics and Systems
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• v.9 no.4
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• pp.284-295
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• 2003

The servo tracks of disk drives are constructed at the time of manufacture with the equipment of servo track writer. Because of the imperfection of servo track writer, disk vibrations and head fluctuations during servo track writing process, the constructed servo tracks might deviate from perfect circles and take eccentric shapes. The servo track writing error should be corrected because it might cause interference with adjacent tracks and irrecoverable operation error of disk drives. The servo track writing error is repeated every disk rotation and so is periodic time function. In this paper, we propose a new correction algorithm of servo track writing error based on iterative teaming approach. Our correction algorithm can learn iteratively the servo track writing error as accurately as is desired. Furthermore, our algorithm is robust to system model errors, is computationally simple, and has fast convergence rate. In order to demonstrate the generality and practical use of our work, we present the convergence analysis of our correction algorithm and some simulation results.

• The Korean Journal of Pain
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• v.12 no.2
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• pp.231-234
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• 1999

Until several years ago we didn't think seriously about cervical problems as a cause of headaches, but since the publication of articles by Bogduk et al they have gotten more attention. Cervical headaches are associated with movement abnormalities of the structures of the neck such as cervical nerve roots, discs, joints and soft tissues. Considering this, we thought that the atlanto-axial joint could be one of the causes of these headaches. Headaches originating from this joint can be recognized by the fact that the pain worsens with rotation of the head in the horizontal plane. Pain can also be referred to the frontal area or around the orbit. We did atlanto-axial joint blocks using a posterior approach on 10 patients who suffered from this type of headache. The results were promising with 9 out of 10 patients showing more than 50% improvement on the numeric rating scale. There were no serious complications observed. We concluded that the atlanto-axial joint block can be an effective procedure in treating this specific type of headache.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.89-90
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• 2008

본 논문은 네트워크를 통해서 이동로봇을 원격제어하기 위해 필요한 비전 시스템에서 HMD(Head Mounted Display)의 방향각 측정 알고리즘에 관한 연구이다. 우선 이 이동로봇 원격제어 시스템은 AP와 무선랜을 이용하여 독립 무선 네트워크를 구축하였고 이동로봇의 주변 환경을 레이저 센서와 스테레오 카메라를 이용하여 사용자에게 정보를 전송한다. 스테레오 카메라를 통해 전송된 영상 정보는 HMD를 통하여 볼 수 있다. 실시간으로 영상 카메라에 의해 측정 된 HMD의 회전 각도는 pen-tilt에 전송되어 HMD가 회전한 만큼 pen-tilt도 회전하여 이동로봇의 주변 환경 영상정보를 얻을 수 있는 알고리즘을 제안하였다.

• Journal of Korean Neurosurgical Society
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• v.54 no.3
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• pp.243-245
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• 2013

Bow hunter's syndrome (BHS) is rare cause of vertebrobasilar insufficiency that arises from mechanical compression of the vertebral artery by head rotation. There is no standardized diagnostic regimen or treatment of BHS. Recently, we experienced 2 cases resisted continues medication and treated by surgical approach. In both cases, there were no complications after surgery and there were improvements in clinical symptoms. Thus, we describe our cases with surgical decompression with a review of the relevant medical literature.

• 한국전산유체공학회:학술대회논문집
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• 2001.10a
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• pp.118-125
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• 2001

The performance prediction of SMART MCP was performed using a computational fluid dynamics code. General capacity-head performance curve of MCP, which is provided to other design branches as design input, was obtained and it showed the typical type of axial pump performance curve. When four MCPs operate in parallel and one of them stops while the others continue to operate, SMART requires reduced power operation. A procedure for predicting the performance of SMART MCP for that case was developed and verified with available experimental data. An analysis based on the developed procedure was performed for two cases; the impeller of sloped MCP is fixed or free to rotate in reverse direction. According to the results, $73\%$ flow rate of normal operation enters the reactor core in the case of the locked impeller. In case of the impeller free rotation, the flow rate entering the reactor core is $62.8\%$.

• Journal of Korean Neurosurgical Society
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• v.41 no.4
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• pp.264-266
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• 2007

Atlantoaxial facet joint osteoarthritis is rare, often undiagnosed because it may be misdiagnosed as occipital neuralgia, or degenerative cervical spondylosis. Unilateral occipitocervical pain aggravated by head rotation is a specific symptom. Conservative treatment is usually effective. But when the patient complains of intractable neck pain localized to occipitocervical junction and unresponsive to medical therapy, surgical treatment should be considered. Though a few reports of surgically treated atlantoaxial osteoarthritis has been published, surgical outcome is favorable. A case of a surgically treated atlantoaxial osteoarthritis is presented with a review of the literatures.

• Journal of Korea Multimedia Society
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• v.6 no.4
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• pp.594-600
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• 2003

In this paper, we propose a detection method for facial features in color images with various backgrounds and face poses. To begin with, the proposed method extracts face candidacy region from images with various backgrounds, which have skin-tone color and complex objects, via the color and edge information of face. And then, by using the elliptical shape property of face, we correct a rotation, scale, and tilt of face region caused by various poses of head. Finally, we verify the face using features of face and detect facial features. In our experimental results, it is shown that accuracy of detection is high and the proposed method can be used in pose-invariant face recognition system effectively

• Geotechnical Engineering
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• v.2 no.2
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• pp.37-46
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• 1986

The analysis of laterally loaded piles in sand Is presented through the finite element algorithm using p-y curve. The soil modulus are found iteratively where the reaction in the Winkler model is coincided with that in the f-y curve. Through the finite element algorthm, the direct considevation for the dependent effect of all other depths to a particular depth is possible. Pile head deflection and rotation are computed by this method and compared with field experimental data of statically loaded piles at the Kwang-yang steel mill construction site. The results of this method are compared with the field experimental date of statically loaded piles tested at the Kwang-yang steel mill construction site.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.173.1-173
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• 2001

This paper proposes the methodology in image processing algorithm that estimates the pose of the pipe crawling robot. The pipe crawling robots are usually equipped with a lighting device and a camera on its head for monitoring and inspection purpose. The proposed methodology is using these devices without introducing the extra sensors and is based on the fact that the position and the intensity of the reflected light varies with the robot posture. The algorithm is divided into two parts, estimating the translation and rotation angle of the camera, followed by the actual pose estimation of the robot. To investigate the performance of the algorithm, the algorithm is applied to a sewage maintenance robot.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.309-314
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• 2001

The balance of high speed spindle system with high precision rotation like grinding machine is very important. Traditionally, we use trial and error method to balance the spindle. It takes much time. So we are developing the automatic balancing equipment being used in the grinding machine. The balancing head we develop is wireless. It will be used high-speed grinding machine. We use influence coefficient method to control the automatic balancer. Experiments are based on automatic and manual balancing. We perform test of the vibration filter. It helps to remove noise. The filter and experiments with automatic balancing controller show that automatic balancing control can be successfully achieved with the quick response and good stability characteristics.