• Journal of Digital Convergence
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• v.11 no.2
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• pp.215-220
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• 2013

They are well-known geometric properties of a circle that the perpendicular bisector of a chord passes through the center of a circle, and the intersection of the perpendicular bisectors of any two chords is its center. This paper is related to a fast pupil detection method capable of detecting the center and the radius of a pupil using these geometric properties at high speed when detecting the pupil region for iris segmentation. The proposed method is characterized as rapidly detecting the center and the radius of the pupil, extracting the candidate points of the circle in human eye images using morphological operations, and finding two chords using four points on the circular edge, and taking the intersection of the perpendicular bisectors of these two chords for its center. The proposed method can not only detect the center and the radius of a pupil rapidly but also find partially occluded pupils in human eye images.

• Physical Therapy Korea
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• v.8 no.4
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• pp.17-29
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• 2001

발목에 대한 유착성 테이핑의 적용은 물리치료 분야와 운동 트레이닝 분야에서의 일반적인 치료 접근 방법이라 할 수 있다. 즉 발목 염좌 같은 손상을 예방하기 위한 방법과 재활의 부가적인 치료 형태로 이용될 수 있는 것이다. 본 연구는 발목의 테이핑과 트레드밀에서의 30분간 보행이 수직 착지 동작 동안 하지의 운동 역학적 요소들에 어떠한 영향을 주는지 알아보기 위해 시행되었다. 14명의 신체 건강한 대상자들 (남:10, 여:4)이 본 연구에 참여하였다. 한발로 서있는 동안 40 cm의 높이로 뛰게 하였다. 가자미근, 전경골근, 안쪽넓은근, 넙다리 두갈래근에 근전도 전극이 부착되었다. 테이핑된 신체 부위로 착지하는 동안 근전도와 힘판(force plate) 자료가 500 Hz의 주파수로 수집되었다. 대상자들의 우세쪽 하지 발목에 테이핑을 하였고, 대상자는 한발로 뛰어 내리는 동작을 반복하였다. 트레드밀에서 30분 동안 발목에 테이핑을 한 채로 보행하였고 이후 한발로 뛰어 내리는 동작을 반복하여 수행하였다. 테이핑을 적용한 상태와 테이핑한 채로 30분 동안 트레드밀에서 걷기 운동을 한 조건에서 수직 지면 반발력의 통계학적으로 유의미한 증가가 있었다. 착지 동안에 네 가지 상황에서의 최대 내측 가속도의 유의한 차이가 있었고, 그 차이는 테이핑 전과 테이핑을 한 채로의 운동 조건에서 유의한 차이가 있었다. 테이핑한 상태에서 가자미근은 접촉되는 착지 순간부터 최대 수직 지면 반발력이 나타나는 동안의 평균 근전도의 수치에 있어서 유의한 감소가 있었다. 반면에 다른 근육들에서는 아무런 변화를 보이지 않았다. 비록 발목 테이핑이 발목 손상의 위험을 줄이는데 효과적이라고 일반적으로 인식되고 있으나 이번 실험의 결과는 30분 동안의 트레드밀에서의 보행 후 테이핑은 발목의 움직임을 제한하는 효과는 있지만 한편으로는 가자미근의 활동을 감소시키는 것을 보여주었다. 따라서 이 연구의 결과는 테이핑을 하면 점프와 착지로 이어지는 동작 중에 발목관절 손상 위험을 증가시킬 가능성이 있음을 보여주었다.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.4
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• pp.241-248
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• 2022

Shear Reinforcement of Dual Anchorage(SRD) is used to reinforce the safety of reinforced concrete structures at construction sites. Welding is used to make shear reinforcement, and welding plays an important role in determining productivity and competitiveness of products. Therefore, a weld bead detection inspection is required. In this paper, we suggest an algorithm for inspecting welding beads using image data of welding beads. First, the proposed algorithm calculates a brightness value in a vertical direction in an image, and then divides a welding bead in a vertical direction by finding a position corresponding to a 50% height point of the brightness value distribution in the image. The welding bead area is also divided in the same way for the horizontal direction, and then the segmentation image is analyzed if there is a welding bead. The proposed algorithm reduced the amount of computation by performing analysis after specifying the region of interest. In addition, accuracy could be improved by using all brightness values in the vertical and horizontal directions using the difference of brightness between the base metal and the welding bead region in the SRD image. The experiment compared the analysis results using five algorithms, such as K-mean and K-neighborhood, as a method to detect if there is a welding bead, and the experimental result proved that the proposed algorithm was the most accurate.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.6
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• pp.1079-1090
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• 2014

Data mining is a technique to get the useful information that can be utilized for marketing and pattern analysis by processing the data that we have. However, when we use this technique, data provider's personal data can be leaked by accident. To protect these data from leakage, there were several techniques have been studied to preserve privacy. Vertically partitioned data is a state called that the data is separately provided to various number of user. On these vertically partitioned data, there was some methods developed to distinguishing kth element and (k+1) th element by using score. However, in previous method, we can only use on two-party case, so in this paper, we propose the extended technique by using paillier cryptosystem which can use on multi-party case.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.284-287
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• 2003

본 논문은 시각 장애인을 위해 양면 인쇄된 점자를 스캐너를 통해서 읽어 들인 후, 영상 내의 잡음과 같은 미세 정보를 제거하는 전처리과정을 거친다 스캔한 영상을 임계값을 이용한 클리핑으로 이진영상을 만든 후 영상의 특징을 추출한다. 추출된 특징은 점자의 앞면과 뒷면으로 분류할 수 있다. 점자 앞면의 특징이 아래반원으로 나타나며 이러한 특징을 이용한 검출필터를 만들어 점자의 앞면만을 추출해낸다. 영상을 각각 수직방향, 수평방향으로 투영시켜 점자영상 분할을 위한 거리를 계산, 자간격과 줄간격을 구해 ½되는 지점에 선을 그어 분할한다. 분할된 점자 형태소를 낱자로 인식한다.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.37-43
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• 2013

Purpose: The present study was conducted to investigate whether the directions of eye movement in playing computer games for certain period affected the change of near point of convergence (NPC) and fusional reserve (FR) or not. Methods: Total 40 subjects in 20s who have the visual acuity of 1.0 or higher without any ocular disease and accommodative dysfunction were asked to successively play computer games. After the subjects were moving eyes in horizontal and vertical directions for 40 and 90 minutes, their horizontal fusional reserves, vertical fusional vergence and near point of convergence were measured. Results: The near point of convergence showed a tendency to be receded after computer gaming in the horizontal and vertical directions, and both of horizontal and vertical fusional reserves were significantly reduced. The range of declined fusional reserves and receded near point of convergence after computer gaming for 90 minutes was smaller than those after computer gaming for 40 minutes. The change of binocular vision was affected by the horizontal eye movement rather than the vertical movement when analyzed by the direction of eye movement. Conclusions: This study revealed that the change in FR and NPC was different along with dominant direction of eye movement during visual display terminal (VDT) tasks. Therefore, the adjustment of VDT working time is required to prevent the dysfunction of binocular vision according to the dominant direction of eye movement during VDT task.

• Korean Journal of Optics and Photonics
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• v.7 no.4
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• pp.419-427
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• 1996

Thermally-stabilized fiber-optic current sensors are proposed and demonstrated. The sensor head is made of two coil formers combined perpendicularly. In this sensor head, bending-induced birefringences can be reduced to the level much smaller than those of the single former type because the eigen-axes of the two perpendicular coil formers are made orthogonal to each other. Moreover, thermal variation of the birefringence is also expected to be minimized by the orthogonality of the two polarization eigen-axes. We changed the temperature slowly in the range of 20~45$^{\circ}C$ during 100 minutes. The overall linearity of the sensor is better than 1.2% in the range of 0~1000A. The long-term fluctuation of the sensor is less than 1% when measured for 3 hours at 500A and room temperature. Two orthogonally-polarized laser diodes are combined together to make the incident beam unpolarized. In the signal processing, the signals are separated by two parts and normalized respectively, which minimize the efects of optical fluctuations coming from sources, connectors, etc.

• Journal of the Korean Geophysical Society
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• v.9 no.1
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• pp.1-6
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• 2006

To remove ringing and increase vertical resolution of GRP data, signature deconvolution was applied to GPR data obtained using a 100 MHz antenna in the Soyang Lake. The signature was extracted through stacking reflection signals from the lake bottom. Results of this deterministic deconvolution was compared with those from the conventional Wienner method. Due to increased vertical resolution, both deconvolution methods are able to resolve three or more layers in an apparent single layer on the input data. However, identification of reflection boundaries from ringing is not easy due to poor definition in the output data of the Wienner filter. On the contrary, the signature deconvolution greatly enhances both vertical resolution and definition of reflection boundaries, showing detailed internal stratigraphic features of the three sedimentary layers. Since extraction of signature at various depths is possible, this deconvolution method can be appled effectively to unstationary GPR data.

• Physical Therapy Korea
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• v.9 no.4
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• pp.37-44
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• 2002

이 연구의 목적은 발목에 테이핑을 한 후 40 cm의 높이에서 한 발로 수직착지를 할 때 발목관절에서의 테이핑 효과를 분석하는 것이었다. 대상자는 20대의 건강한 성인 14명(남자 4명, 여자 10명) 이었다. 대상자에게 적용한 조건은 테이핑 전, 테이핑 적용, 30분 동안 트레드밀에서 걷기, 테이핑 제거상태 이었고 맥리플렉스(MacReflex)를 이용하여 발끝이 지면에 닿은 상태에서 발목이 최대 배측굴곡(dorsiflexion) 되기까지 걸린 시간, 발목관절 각도변화, 각속도를 측정한 후 반복측정에 의한 분산분석으로 비교하였다. 그 결과 네 개의 조건간에는 통계학적으로 유의한 차이가 없었다(p>.05). 따라서 발목 테이핑은 수직착지시 발목의 배측굴곡을 제한하는 효과는 없다고 판단된다.

• The Transactions of the Korea Information Processing Society
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• v.3 no.4
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• pp.1002-1013
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• 1996

The segmentation of characters is an important step in the automatic recognition of handwritten text. This paper proposes the segmenting method of off-line handwritten Hangul. The suggested approach is based on the structural characteristics of Hangul. The first step extracts the local features. connected component and strokes from the imput word. In the second step we identify the class of strokes. The third segmenting step specifies WRC(White Run Column) before consonant or horizontal vowel. If the segment is longer than threshold, the system estimates segmenting columns using the consonant-vowel information and column features, and then finds a cornered boundary along the strokes within the estimated segmenting columns.