• Journal of Biomedical Engineering Research
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• v.34 no.3
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• pp.135-140
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• 2013

We have developed an ultra wide-field of view Optical Coherence Tomography(OCT) which has capability to 2D and 3D views of cross-sectional structure of in vivo human retina. Conventional OCT has a limitation in visualizing the entire retina due to a reduced field of view. We designed an optical setup to significantly improve the lateral scanning range to be more than 20 mm. The entire human retinal structure in 2D and 3D was reported in this paper with the developed OCT system. Also, we empirically searched an optimized image size for real time visualization by analyzing variation of the frame rate with different lateral scan points. The size was concluded to be $1024{\times}2000{\times}300$ pixels which took 9 seconds for visualization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.601-604
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• 2007

In this paper dose a laver surface check using a real time image process. This system does false retrieval of a laver at a laver production line. At first, a laver image was read in real time using a CCD camera. In this paper, we use an area scan CCD camera. Image is converted into a binary code image using a high-speed imaging process board afterwards. A laver feature is extracted by a binary code image. Surface false retrieval is finally executed using a laver feature. In this paper, we use an area feature of a laver image.

• Proceedings of the KOSOMBE Conference
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• v.1985 no.06
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• pp.22-25
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• 1985

본고에서, "나선형 주사 방법에 의한 고속 NMR 영상화" 방법을 제안하고 그에 따른 실험 결과를 보였다. 이것은 2차원 FID 영역을 나선형 궤적으로 스캐닝하며 데이타를 받을 수 있도록 경사 자계 파형 (gradient pulse)을 가하여 빠른 시간에 (수십 msec - 수초)내에 영상 정보를 얻어낸 후, 재구성 알고리즘을 씀으로써 영상을 얻어내는 방법이다. 이 방법의 장점은 첫째로 $T_2$ 감쇄에 의한 PSF (Point Spread Function)가 윈형 대칭으로 주어지므로 영상화 했을때 물체의 구조 식별이 기존의 EPI (Echo Planar Imaging) 방법에 비해서 선명하며, 둘째로 나선형 궤적을 구현하기 의한 경사 자계 파형에서 불연속 점을 없앰과 동시에 파형의 세기가 점차로 증가하는 형태이므로, 기존의, 파형 왜곡에 의해 영상에 미치는 영향을 최소화 할 수가 있으며, 세째로 나선형 스캔을 사이 사이에 끼워 넣는 방법을 씀으로써 해상도를 향상시킬 수가 있다.

• Transactions of Materials Processing
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• v.27 no.5
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• pp.314-322
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• 2018

AlSi12 is a heat-resistant aluminum alloy that is lightweight, corrosion-resistant, machinable and attracting attention as a functional material in aerospace and automotive industries. For that reason, AlSi12 powder has been used for high performance parts through 3D printing technology. The purpose of this study is to observe deposition characteristics of AlSi12 powder in a direct energy deposition (DED) process (one of the metal 3D printing technologies). In this study, deposition characteristics were investigated according to various process parameters such as laser power, powder feed rate, scan speed, and slicing layer thickness. In the single track deposition experiment, an irregular bead shape and balling or humping of molten metal were formed below a laser power of 1,000 W, and the good-shaped bead was obtained at 1.0 g/min powder feed rate. Similar results were observed in multi-layer deposition. Observation of deposited height after multi-layer deposition revealed that over-deposition occurred at all conditions. To prevent over-deposition, slicing layer thickness was experimentally determined at given conditions. From these results, this study presented practical conditions for good surface quality and accurate geometry of deposits.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.272-276
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• 2000

Reverse engineering refers to the process that creates a physical part from acquiring the surface data of an existing part using a scanning device. In recent years, as the non-contact type scanning devices become more popular, the huge amount of point data can be obtained with high speed. The point data handling process, therefore, becomes more important since the scan data need to be refined for the efficiency of subsequent tasks such as mesh generation and surface fitting. As one of point handling functions, the cross-sectioning function is still frequently used for extracting the necessary data from the point cloud. The commercial reverse engineering software supports cross-sectioning functions, however, these are only for cross-sectioning the point cloud with the constant spacing and direction. In this paper, adaptive cross-sectioning point cloud which allow the changes of the spacing and directions of cross-sections according to the constant spacing and direction. In this paper, adaptive cross-sectioning algorithms which allow the changes of the spacing and directions of cross-sections according to the curvature difference of the point cloud data are proposed.

• Physical Therapy Korea
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• v.9 no.1
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• pp.63-68
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• 2002

Foot ulceration results in substantial morbidity in patients with peripheral neuropathy. The purpose of this study was to find the relationship of plantar foot pressures during walking to plantar ulceration in patients with Hansen's disease. The subjects were recuruited from two Welfare Clinic for Hansen's disease in Wonju and Uiwang city. Ten subjects (5 females, 5 males) with plantar ulceration and a mean age of 63 years were evaluated in this study. The mean duration of Hansen's disease in these subjects was 30 years. Plantar pressures were measured during self-selected comfortable walking speed by using MatScan system. Three subjects had plantar ulceration under the first metatarsal head. Five subjects had plantar ulceration under the second and third metatarsal head. Two subjects had plantar ulcers under the fifth metatarsal head. Eight of 10 subjects had plantar ulceration at highest pressure point that measured during walking. This result suggests that the abnormal high plantar pressure could be related factor to plantar ulceration in patients with Hansen's disease. Also the foot pressure measurement may be useful to evaluate the risk of plantar ulceration in patients with Hansen's disease.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.10
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• pp.34-39
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• 2010

We developed a path algorithm for ultrafast/wide area laser processing. Demands for high precision laser processing with a wide area has been increasing for a number of applications such as in solar cell battery, display parts, electronic component and automobile industry. Expansion of the area in which laser processing is an important factor to handle the ultrafast/wide area processing, it will require a processing path. Processing path is path of 2- axis stage and stage of change in velocity can be smooth as possible. In this paper, we proposed a smoothingnurbs method of improved speed profile. This method creates soft path from edge part, it is main purpose that scan area ($50mm{\times}50mm$) inside processing path makes path of topology of possible straight line. We developed a simulation tool using Visual C++.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.125-132
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• 2002

We use a compound-cam twin arm structure and random tool access method to achieve a faster ATC (Automatic Tool Changer) system for the accurate position and rotation control of a tool magazine and an exchange am. Based on the data obtained from various sensors, it is possible to follow the sequence of commands in each control step for an exchange arm. However, it is not so easy to reduce the exchange time of the system because of the slow responses of the sensors and execution mode delays of PLC (Programmable Logic Controller) scan time. In this paper, we propose a new programmed limit-switch position control method to obtain the shortest possible delays for the random tool access method and compound-cam twin arm structure. With some experimental results, we have achieved below 0.9sec tool exchange time with the proposed method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.5 s.110
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• pp.514-520
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• 2006

In this study, the performance of a digital pile rebounding and penetration monitoring system (DPRMS) is evaluated and the measurement precision of the DPRMS is improved. The DPRMS is a high speed line-scanning camera system to measure the rebound and penetration of a pile in a construction work. A main problem in the DPRMS is a measurement error, which is caused by a shock or vibration due to a hammer impact. The measurement error is investigated by analyzing vibration signals of the DPRMS during the impact. Moreover, the frequency response functions of the DPRMS are also analyzed. As a result, it is found that the tripod height has an influence on the DPRMS performance and a shorter tripod is better. One more founding in this study is that the DPRMS should be placed with a appropriate distance from a pile for improving the measurement precision.

• Tuberculosis and Respiratory Diseases
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• v.83 no.3
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• pp.195-200
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• 2020

The disease concept of interstitial lung disease with idiopathic pulmonary fibrosis at its core has been relied on for many years depending on morphological classification. The separation of non-specific interstitial pneumonia with a relatively good prognosis from usual interstitial pneumonia is also based on the perception that morphology enables predict the prognosis. Beginning with dust-exposed lungs, initially, interstitial pneumonia is classified by anatomical pathology. Diagnostic imaging has dramatically improved the diagnostic technology for surviving patients through the introduction of high-resolution computed tomography scan. And now, with the introduction of therapeutics, the direction of diagnosis is turning. It can be broadly classified into to make known the importance of early diagnosis, and to understand the importance of predicting the speed of progression/deterioration of pathological conditions. For this reason, the insight of "early lesions" has been discussed. There are reports that the presence or absence of interstitial lung abnormalities affects the prognosis. Searching for a biomarker is another prognostic indicator search. However, as is the case with many chronic diseases, pathological conditions that progress linearly are extremely rare. Rather, it progresses while changing in response to environmental factors. In interstitial lung disease, deterioration of respiratory functions most closely reflect prognosis. Treatment is determined by combining dynamic indicators as faithful indicators of restrictive impairments. Reconsidering the history being classified under the disease concept, the need to reorganize treatment targets based on common pathological phenotype is under discussed. What is the disease concept? That aspect changes with the discussion of improving prognosis.