• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.4
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• pp.503-508
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• 1997

The change of the structure of homogeneous turbulence subject to irrotational strains has been studied in an anti-Morel type diffuser (center matched cubic contour) using the hot wire anemometry. It was observed that the profiles of mean velocities and turbulence velocities along the center line were stable at the entrance region but rapidly changed near the matching point. The wall induced turbulence at the entrance region grows fast and was diffused toward the center at downstream. It was also observed that the axial turbulence grows faster than the radial one in the middle region of the diffusing flow and that the diffusing process has the vortex compression mechanism due to the conservation of angular momentum. These phenomena are frequently observed at the initial flow region of the free jet.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.191-194
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• 2000

일반 적인 고속 블록 정합 알고리즘들은 현재 프레임의 탐색 블록과 참조 프레임의 탐색영역 내의 블록간 MAD(Mean Absolute Distance)를 구하여 그 값을 탐색 점으로 사용하므로 탐색 점 수만큼 MAD를 구해야 하는 단점이 있다. 이와 같은 고속 블록 정합 알고리즘들의 단점을 해결하기 위해 탐색 점 예측에 의한 고속 블록 정합 알고리즘을 제안한다. 본 논문에서는 "이웃 한 화소는 서로 간에 거의 같은 값을 지니고 있다"라는 성질을 이용하여, 이웃 한 탐색 점 두개의 MAD 평균값을 계산하여 그 값을 새로운 탐색 점으로 사용하여 탐객 하기 때문에 탐색 점 수는 DS(Diamond Search)알고리즘과 비교하여 비슷하지만, 최소 오차가 center일 때의 탐색 점을 예측에 의해 산출 하므로 총 연산량은 2Ep$N_2$만큼 크게 줄어든다. Ep는 예측 탐색 점 수를 나타내며, N은 블록의 크기를 나타낸다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.118-121
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• 2003

지문을 이용한 개인 인증 절차는 지문 형태 별로 구분하는 분류(classification) 과정과 본인임을 확인하는 정합(matching) 과정으로 구분할 수 있다. 지문의 분류와 정합을 위해서는 기존 연구들이 지문의 특징점 수와 방향성의 흐름 패턴에 의존한다. 본 논문에서는 방향성의 흐름 패턴을 이용한 중심점 추출에 초점이 맞춰져 있으며 추출된 중심점 정보는 현재 구현되어진 특징점 추출 정보와 연계해 정합을 위한 기준점으로 활용한다. 중심점 추출 방식은 입력된 지문 영상에 대해 3 $\times$ 3 Sobel 마스크를 적용한 후 8 $\times$ 8블록 영상을 분할하여 각 대표 방향 성분을 추출하며 추출되어진 방향 성분과 특이점 패턴을 비교하여 중심점을 탐색한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.775-782
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• 2006

We generated blocks from the direction-extracted fingerprint during the pre-process of the fingerprint recognition algorithm and performed training by using the direction minutiae of each block as the input pattern of the neural network, so that we extracted the core points to use in the matching. Based on this, we designed the fingerprint recognition embedded system and tested it using the control board and the serial communication to utilize it for a variety of application systems. As a result, we can verify the reliance satisfactorily.

• Textile Coloration and Finishing
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• v.25 no.2
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• pp.102-109
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• 2013

A new series of anthraquinoid magenta dyes having alkylphenyl substituents was synthesized and applied toward pure polypropylene fibers. The affinity of the dyes toward polypropylene fibers was increased gradually with the increase of the length of alkyl substituents. The optimum length of alkyl group was determined as heptyl substituents from the practical point of view. The color values of the dyes on polypropylene fabrics displayed slight bluish red, namely magenta which is more practical than primary red in color matching. The good fastness ratings to washing, rubbing and light were obtained for the dyes having longer alkyl groups than hexyl substituents. Expecially they exhibited ratings 4 of light fastness, which is higher than primary red dyes previously reported.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.189-190
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• 1998

In this paper, we show the realtime 3D reconstruction algorithm with the sliced CT images. The preprocessing is thresholding, labeling, contouring, and extracting dominant point. we reconstruct 3D image with dominant points using dynamic matching technique. The software implemented in Visualc++ 5.0 as a window-based application program.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.269-270
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• 1998

Image-guided surgery (IGS) system has become well known in the field of neurosurgery and spine surgery. A patient's anatomy is first registered to preoperatively acquired CT/ MRI data using the point matching algorithm. A magnetic field digitizer was used to measure the physical space data and the system was based on Workstation of Unix system. To evaluate the spatial accuracy of interactive IGS system, the phantom consisting of rods varied height and known location was used. The RMS error value between CT/MR images and real location was 3-4mm. For the more convenience of the surgery, we provide various image display modules.

• Journal of Welding and Joining
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• v.19 no.2
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• pp.200-207
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• 2001

Three-diemnsional bead profile was measured using the biprism stereo vision sensor in GMAW, which consists of an optical filter, biprism and CCD camera. Since single CCD camera is used, this system has various advantages over the conventional stereo vision system using two cameras such as finding the corresponding points along the horizontal scanline. In this wort, the biprism stereo vision sensor was designed for the GMAW, and the linear calibration method was proposed to determine the prism and camera parameters. Image processing techniques were employed to find the corresponding point along the pool boundary. The ism-intensity contour corresponding to the pool boundary was found in the pixel order and the filter-based matching algorithm was used to refine the corresponding points in the subpixel order. Predicted bead dimensions were in broad agreements with the measured results under the conditions of spray mode and humping bead.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.3
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• pp.459-470
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• 2013

The discovery of nearest neighbors, without training in advance, has many applications, such as the formation of mosaic images, image matching, image retrieval and image stitching. When the quantity of data is huge and the number of dimensions is high, the efficient identification of a nearest neighbor (NN) is very important. This study proposes a variation of the KD-tree - the arbitrary KD-tree (KDA) - which is constructed without the need to evaluate variances. Multiple KDAs can be constructed efficiently and possess independent tree structures, when the amount of data is large. Upon testing, using extended synthetic databases and real-world SIFT data, this study concludes that the KDA method increases computational efficiency and produces satisfactory accuracy, when solving NN problems.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.17-23
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• 1997

In the two-dimensional Finite Element Method for forming simulation, mesh generation and remeshing process are very significant. In this paper, using the modified splitting mesh generation algorithm, we can overcome the limitation of existing techniques and acquire mesh, which has optimal mesh density. A modified splitting algorithm for automatically generating quadrilateral mesh within a complex domain is described. Unnecessary meshing process for density representation is removed. Especially, during the mesh generation with high gradient density like as shear band representation, the modified mesh density scheme, which will generate quadrilateral mesh with the minimized error, which takes effect on FEM solver, is introduced.