• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.449-455
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• 2015

Owing to the trend of an increase in capacity and high-efficiency requirement, the life and reliability of power transformer depend significantly on the amount of heat generation per unit volume and the degradation of insulation oil. These problems can be solved by enhancing the cooling performance of the radiator. The purpose of this study was to find a suitable position of fans for a better cooling effect given by the forced-convection of air in an ONAF (Oil Natural Air Forced) type transformer. In the simulation, commercial software was used for flow analysis, and the cooling passage of the oil was simplified to shorten the time taken for computation. With the diameter of the fan fixed at a constant value, the analysis was performed only by changing the position of the fans. As a result, a vertical position change of the fans does not affect the cooling performance significantly. However, the temperature drop given by the fans positioned on the front region of the transformer is larger than that on the rear region.

• Journal of Internet Computing and Services
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• v.20 no.4
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• pp.39-46
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• 2019

In recently years, it has become important to detect underground objects of various marterials including metals, such as detecting the location of sink holes and pipe. For this reason, ground penetrating radar(GPR) technology is attracting attention in the field of underground detection. GPR irradiates the radar wave to find the position of the object buried underground and express the reflected wave from the object as image. However, it is not easy to interpret GPR images because the features reflected from various objects underground are similar to each other in GPR images. Therefore, in order to solve this problem, in this paper, to estimate the piping position in the GRP image according to the threshold value using the CNN (Convolutional Neural Network) model based on deep running, which is widely used in the field of image recognition, As a result of the experiment, it is proved that the pipe position is most reliably detected when the threshold value is 7 or 8.

• The Journal of the Acoustical Society of Korea
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• v.37 no.6
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• pp.437-442
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• 2018

In this paper, we propose a method for estimating the position of a source in a closed form when a single source has coherently distributed property against a circular array. When a sound source reaches a sensor through multipath environments, it is seen as a distributed source and can be represented by four variables: the nominal azimuth, nominal elevation, azimuth angular spread, elevation angular spread. Therefore, it requires a lot of computation by a search method such as DSPE (Distributed Source Parameter Estimator). In this paper, we propose a method of estimating the nominal azimuth and elevation angle in a closed form using correlation function and least squares method for fast position estimation. In particular, if the source is assumed as Gaussian distribution model, the standard deviation is also estimated in a closed form. In the simulation, the validity of the proposed method is confirmed by comparing with the DSPE.

• Convergence Security Journal
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• v.12 no.1
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• pp.3-8
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• 2012

MANET composed wireless nodes without fixed infrastructure provides high flexibility, but it has weak disadvantage to various attack. It has big weakness to DDoS attack because every node perform packet forwarding especially. In this paper, packet transmission information control technique is proposed to reduce damage of DDoS attack in MANET and search location of attacker when DDoS attacks occur. Hierarchical structure using gateway node is adopted for protect a target of attack in this study. Gateway node in cluster is included like destination nodes surely when source nodes route path to destination nodes and it protects destination nodes. We confirmed efficiency by comparing proposed method in this study with CUSUM and measured the quantity consumed memory of cluster head to evaluate efficiency of information control using to location tracing.

• Journal of Digital Convergence
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• v.10 no.2
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• pp.237-242
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• 2012

This paper proposed image matching technique that find out the truth of the wild ginseng through smart phone when the common person discovered a plant like a wild ginseng. Also sharing a location and information by SNS, we can improve the probability of wild ginseng discovery. Image matching technique using OpenCV porting in android finds out the truth of the wild ginseng with comparing existing it. Thus we are able to compare and analysis them in our application program. For more verification, we added marking function of wild ginseng position for information sharing between users.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.260-265
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• 2015

This paper proposes a alignment system using edge feature. An alignment system obtains the position and orientation of printed circuit board(PCB) or liquid crystal display(LCD) panel through the fiducial marks. Thus, it is the indicator of the system performance how accurate we detect the positions of the fiducial marks in the target image. Edges have the geometrical characteristics such as positions, lengths, and shapes. These features are suitable for finding the marks and have the advantages of lighting variations, model occlusion, as well as variations in scale and angle. The performance of the proposed system is validated through the alignment experiment using an display panel alignment system included X, Y axis, and rotatable stage.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.413-416
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• 2011

Flip top cap은 경량성, 가공성, 내식성 우수하여 최근에 생활 용기 뚜껑으로 많이 활용되고 있다. Flip top cap은 사출성형에 의해 제작 되며 사출성형 과정에서 힌지부분에 웰드라인(Weldline)이 형성되어 기계적 강도가 떨어지게 된다. Flip top cap은 생활용기에 사용되며 실제생활에서 많은 작동을 요구하기 때문에 힌지부분의 웰드라인은 제품불량에 큰 원인이 된다. 또한 Flip top cap은 생산성을 높이기 위해 멀티캐비티(Multi-cavity) 사출방식을 선호한다. 멀티캐비티 방식은 높은 사출압력을 요구하기 때문에 사출품의 불량과 사출기에 많은 부하가 예상된다. 본 연구에서는 게이트 위치를 조정함으로써 사출품 힌지부분에서 발생할 수 있는 웰드라인을 품질에 영향이 없는 곳으로 이동시키고 최적의 사출 압력을 찾기 위한 유동해석을 통해 최적의 사출조건을 도출함으로써 Flip top cap의 기계적 품질과 제품생산성 향상을 위한 연구가 수행되었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.343-346
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• 2003

기존 쾌속조형시스템의 단점을 보완하기 위해 본 연구팀에서 개발한 쾌속조형시스템을 수직절단에 의해 층별 성형할 경우 가공된 물체의 표면에 계단형 표면과 같은 왜곡현상이 발생한다. 이러한 왜곡 현상을 보완하기 위해 수직절단이 아닌 경사절단하여 계단형 윤곽과 같은 표면 왜곡의 문제점을 보완하고자 한다. 최적의 경사절단선분을 구하기 위해 경사절단선분의 길이와 중간층 점의 거리를 정의하여 이를 최소화하는 에너지 함수를 구현하였다. 에너지를 최소화하기 위한 알고리즘으로 급강하법을 사용하였으나, 이 방법은 에너지가 작아지는 방향으로만 움직이기 때문에 물체의 윤곽이 복잡할 경우 최적이 아닌 다른 위치에 귀착하는 지역적 최적해가 발생한다. 본 논문에서는 이러한 지역적 최적해를 벗어나 최적의 경사절단선분을 찾기 위해 유전자 알고리즘을 사용하였다. 유전자 알고리즘을 사용할 경우, 급강하법에서 발생하였던 지역적 최적해 문제가 해결되어 최적의 위치를 찾을 수 있었다.

• Journal of the Korea Society of Computer and Information
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• v.7 no.4
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• pp.46-51
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• 2002

In this paper, I proposed a eyebrow detection algorithm in human face, that is important element in facial recognition. The proposed algorithm consists of four processes: face region detection using color region segmentation. eye detection by template matching, eyebrow candidate region detection in detected eye region, and eyebrow detection by thresholding using the modified histogram that gets luminance value in the candidate region. The test results show that the proposed algorithm can detect eyebrow region very effectively in facial image.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.398-403
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• 2007

초음파 영상은 미세한 명암도 차이 등에 의해 분석 과정에서 근육 영역의 위치와 크기를 판단하는데 어려움이 발생하고 이로 인해 근육 영역을 파악하는데 주관성이 개입된다. 본 논문에서는 근육영역을 객관적으로 분석하기 위해 ART2 신경망을 적용하여 양자화를 수행한 후, 국부적 영역에서 근육 영역을 추출한다. 초음파 영상에서 히스토그램 평활화와 엔드인 탐색 알고리즘을 적용하여 명암도의 분포와 밝기 값을 보정 한 후, ART2 신경망을 이용하여 유사한 영역을 클러스터링 한다. 그리고 클러스터링 된 각 영역의 크기, 위치 및 명암도 정보를 분석하여 피하지방, 근육 막, 기타 배경 영역으로 분류한다. 최종적인 근육 영역을 찾기 위해 근육 막 내부 객체들 간의 거리, 각도를 이용하여 근육 막 영역에 둘러싸인 근육 영역을 추출한다. 실제 초음파 영상을 대상으로 실험한 결과, 일반적인 클러스터링 기법을 적용한 방법 보다 ART2 기반 양자화와 제안된 영역 확장 기법으로 근육영역을 추출하고 분석하는 것이 효율적임을 확인하였다.