• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.43-52
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• 1994

This paper outlines a new approach to the line generalization when preparing small scale map on the basis of existing large scale digital map. Line generalizations are conducted based on Douglas algorithm using 1/25,000 scale topographic maps of southeastern JEJU island which produced by National Geographic Institute to analyze the fitness to the original and problems of graphical representation. Compare to the same scale map which was generated by manual method, a verity of small, but sometimes significant errors ＆ modification of topological relationship have been detected. The research gives full details of three algorithms that operationalize the smallest visible object method, together with some empirical results. A comparison of the results produced by the new algorithms with those produced by manual generalization and Douglas method of data reduction is provided. Also this paper presents the preliminary results of an relationships between the size of smallest visual object and requiring data storages for each algorithms.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.125-132
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• 2010

The authors have investigated the acoustic field analysis using the Constrained Interpolation Profile(CIP) Method recently proposed by Yabe. This study has examined the calculation accuracy of the three-dimensional(3-D) acoustic field analysis using the type C CIP method. In this paper we show phase error of type C CIP method and the dependence on the wave-propagation direction in the type C CIP acoustic field analysis, and then demonstrate that it gives less-diffusive results than conventional analysis. Moreover, in comparison between type C-1 CIP, type C-2 CIP, type M CIP and FDTD, reports the memory requirements and calculation time of each method.

• Geophysics and Geophysical Exploration
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• v.10 no.2
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• pp.154-160
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• 2007

This paper compares the characteristics of three different algorithms for three-dimensional (3D) magnetotelluric (MT) modeling. These methods are developed by Mackie et al. (1994), Sasaki (1999) and Nam et al. (2007). The first and second methods are based on the finite difference method (FDM), while the last one the finite-element method (FEM). MT responses, apparent resistivities and phases, for a COMMEMI 3D-2 model show a good agreement with integral equation solutions and only minor discrepancies are found over the anomalous bodies in the 3D model. The computation time of the two methods based on FDM is short and the static divergence correction contributes to speed up. The FEM modeling scheme is accurate but slow.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.379-386
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• 2005

This paper provides a rigorous theory for analysis of quantization effects and optimum filter bank design in quantized multidimensional subband filter banks. Even though subband filter design has been a hot topic for last decades, a few results have been reported on the subband filter with a quantizer. Each pdf-optimized quantizer is modeled by a nonlinear gain-plus-additive uncorrelated noise and embedded into the subband structure. Using polyphase decomposition of the analysis/synthesis filter banks, we derive the exact expression for the output mean square quantization error. Based on the minimization of the output mean square error, the technique for optimal filter design methodology is developed. Numerical design examples for optimum nonseparable paraunitary and biorthogonal filter banks are presented with a quincunx subsampling lattice. Through the simulation, $10\~20\;\%$ decreases in MSE have been observed compared with subband filter with no quantizers especially for low bit rate cases.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.139-146
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• 2004

A 2D/3D complex optical system and its vision inspection algerian is proposed and implemented as a single probe system for high speed, precise vision inspection of the solder pastes. One pass un length labeling algorithm is proposed instead of the conventional two pass labeling algorithm for fast extraction of the 2D shape of the solder paste image from the recent line-scan camera as well as the conventional area-scan camera, and the optical probe path generation is also proposed for the efficient 2D/3D inspection. The Moire interferometry-based phase shift algerian and its optical system implementation is introduced, instead of the conventional laser slit-beam method, for the high precision 3D vision inspection. All of the time-critical algorithms are MMX SIMD parallel-coded for further speedup. The proposed system is implemented for simultaneous 2D/3D inspection of 10mm${\times}$10mm FOV with resolutions of 10 ${\mu}{\textrm}{m}$ for both x, y axis and 1 ${\mu}{\textrm}{m}$ for z axis. Experiments conducted on several nBs show that the 2D/3D inspection of an FOV, excluding an image capturing, results in high speed of about 0.011sec/0.01sec, respectively, after image capturing, with $\pm$1${\mu}{\textrm}{m}$ height accuracy.

• The Journal of Korean Medicine
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• v.21 no.4
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• pp.148-158
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• 2000

Objective : The purpose of this study was to investigate the back shape of school children using the phase-shifting scanning grating projection moire interferometer, which was developed by the Korea Advanced Institute of Science and Technology and is useful in evaluating three dimensional back shape. Methods : In this study the subjects consisted of 1,358 pupils [711 boys(52.36%), 647 girls(47.64%)] attending elementary and middle schools in Seoul. Their ages ranged from nine to fifteen and the average age was 12.2. With the phase-shifting scanning grating projection moire interferometer, the posterior view of the body were taken to see if there are correlations of moire fringe number, width difference between left and right, and correlation between differences in moire fringe number and width on both sides in the scapular, lumbar and gluteal regions. Results : The results were as follows : I. More frequent findings of fringe were observed on the right in all regions : in the scapular region, 309 boys(43.4%) and 156 girls(24.2%) had more fringe numbers on the right side; in the lumbar region, 68 boys(9.5%) and 11 girls(1.7%); and in the gluteal region, 160 boys(22.4%) and 63 girls(9.8%). Such tendency was striking especially in the scapular and lumbar regions, and in boys rather than in girls. In the scapula, 661 subjects(48.7%) with one moire fringe on either side need further attention and 110 subjects(8.I %) with two or more are required to do follow-up radiography for scoliosis. 2. In an analysis of width difference in the trunk, the left side is wider in all regions except for the gluteal region in boys : in the scapular region 21 boys(3.0%) and 103 girls(15.9%); in the lumbar region, 87 boys(12.2%) and 250 girls(38.6%); and in the gluteal region 197 girls(30.4%) had a wider left side and 45 boys(6.3%) showed a wider right side. 3. In correlation analysis of the number of moire fringe and width difference in each region, the side where more moire fringes were observed was significantly wider in the lumbar and gluteal regions, but not in the scapular region.(p<0.01) Conclusions : From these results, it is concluded that the back shape of elementary and middle school students in Seoul shows that the right side had more moire fringes; the left side was wider; and especially in the lumbar and gluteal regions the side where more moire fringes were observed was wider.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.2
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• pp.69-83
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• 2018

The South China Sea (SCS) is a typical marginal sea characterized with the deep basin, shelf break, shallow shelf, many straits, and complex bathymetry. This study investigated the tidal characteristics and propagation, and reproduced typhoon-induced storm surge in this region using the regional real-time tide-surge model, which was based on the unstructured grid, resolving in detail the region of interest and forced by tide at the open boundary and by wind and air pressure at the surface. Typhoon Haiyan, which occurred in 2013 and caused great damage in the Philippines, was chosen as a case study to simulate typhoon's impact. Amplitudes and phases of four major constituents were reproduced reasonably in general, and the tidal distributions of four constituents were similar to the previous studies. The modelled tide seemed to be within the acceptable levels, considering it was difficult to reproduce the tide in this region based on the previous studies. The free oscillation experiment results described well the feature of tide that the diurnal tide is prevailing in the SCS. The tidal residual current and total energy dissipation were discussed to understand the tidal and sedimentary environments. The storm-surge caused by typhoon Haiyan was reasonably simulated using this modeling system. This study established the regional real-time barotropic tide/water level prediction system for the South China Sea including the seas around the Philippines through the validation of the model and the understanding of tidal characteristics.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.353-361
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• 2013

Previous studies for analyzing optimal haulage routes of dump trucks in open pit mines mostly used raster data. However, the raster data has several problems in performing optimal route analyses: (1) the jagged appearance of haulage roads according the cell resolution often causes overestimation of the travel cost; (2) it difficult to trace the topological relationships among haulage roads. These problems can be eliminated by using vector network data, however a new method is required to reflect the performance characteristics of a dump truck according to terrain gradient changes. This study presents a new method to create vector network data with the consideration of terrain gradient for analyzing optimal haulage routes of dump trucks in open pit mines. It consists of four procedures: (a) creating digital elevation models, (b) digitizing haulage road networks, (c) calculating the terrain gradient of haulage roads, and (d) calculating the average speed and travel time of a dump truck along haulage roads. A simple case study at the Roto South pit in the Pasir open pit coal mine, Indonesia is also presented to provide proof that the proposed method is easily compatible to ArcGIS Network Analyst software and is effective in finding optimal haulage routes of dump trucks with considering terrain gradient in open pit mines.

• Journal of the Korea Computer Graphics Society
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• v.11 no.2
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• pp.40-46
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• 2005

본 논문에서는 스윕곡면(sweep surface)을 기반으로 복잡한 3차원 물체의 형상을 변형하는 새로운 자유형상 변형(free-form deformation)기법을 제시한다. 본 논문에서 제시한 방법은 기존의 격자점(control lattices)을 조정하는 체적기반의 방법에 비해 스윕기반의 절차적 (procedural) 모델링 기법의 직관성을 활용하여 사용자에게 보다 효율적인 형상변형 기법을 제공한다. 3차원 물체의 정점들은 스윕곡면의 단면(cross-section)에 바인딩(binding) 되어 곡면의 변화에 따라 형상변형을 한다. 본 논문에서 제시한 스윕기반 형상변형 기법은 3차원 물체를 부분적으로 변형하는 기법과 계층구조를 기반으로 전반적인 형상을 변형하는 기법으로 구분된다. 부분적인 형상변형 기법은 스윕곡면을 구성하는 성분의 다단계(multi-level) 표현을 통하여 사용자에게 다중해상도(multi-resolution) 형상변형 기능을 제공한다. 계층구조에 기반한 형상변형 기법은 복잡한 3차원 물체를 위상구조에 따라 여러 계층으로 분할하고, 각 부분의 형상을 근사하는 스윕곡면들을 생성한다. 분할된 각 부분의 정점(vertices)들은 해당 스윕곡면에 바인딩 되어 스윕곡면의 단면의 변화를 따르게 된다. 이러한 상황하에서 스윕곡면들은 3차원 물체의 계층구조에 따라서 서로 상호작용(interaction)을 하게 되고, 결과적으로 3차원 물체의 각부분은 상호반응적 형상변형을 한다. 이러한 계층구조에 기반한 상호반응적 형상변형 기법은 사용자의 의도에 부합하는 보다 사실적이고 기능적인 형상변형을 가능하게 한다. 본 논문에서는 다양한 3차원 물체에 대한 실험을 통해 제시된 방법의 효율성을 입증한다. 결과 막성 사구체병증과 같은 신질환이 발견될 수 있으므로 신조직검사의 적응증에 합당한 경우 적극적인 신조직검사를 시행하여 원인 질환을 찾는 노력이 필요할 것으로 사료된다.. 남아가 75명으로 남녀비는 3.6:1을 보였다. 임상병리학적 분류상 일차성 신증후군이 89명(92.7%), 이차성 신증후군이 7명(7.3%)이었으며 일차성 신증후군에서 minimal change nephrotic syndrome이 71명으로 79.8%, focal segmental glomerulosclerosis 11.2%, mesangial proliferation 4.5%, membranoprolifrative glomeulonephritis 3.4%, membranous nephropathy 1명 1.1%이었으며 2차성 신증후군은 $Henoch-Sch\"{o}nlein$ nephritis가 3례로 가장 많았다. 미세변화 신증후군 71명 중 비재발군이 16명으로 22.5%, 비빈발 재발군 49.3%, 빈발 재발군 18.3%, 스테로이드 의존군 9.9%를 보였다. 결론 : 대전시에서의 신증후군 환아의 발생빈도는 15세이하 소아 10만명당 약 5명으로 추정되었으며 10여 년전과 비교하여 큰 변화를 보이지는 않았다. 또한 저자들의 임상병리학적 연구결과가 다른 문헌에서 보고된 소아 신증후군의 연구결과와 큰 차이를 보이지 않음을 알 수 있었다. 자극에 차이가 있지 않나 추측되며 이에 관한 추후 연구가 요망된다. 총대장통과시간의 단축은 결장 분절 모두에서 줄어들어 나타났으나 좌측결장 통과시간의 감소 및 이로 인한 이 부위의 통과시간 비율의 저하가 가장 주요하였다. 이러한 결과는 차가운 생수 섭취가 주로 결장 근위부를 자극하는

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.896-905
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• 2004

In this paper, the design, fabrication and experiment on a planar array antenna with a flat-topped radiation pattern for a mobile base station antenna were described. The current distribution of an antenna aperture, which is easily realizable in a feeding network compared with the conventional one of sin(x)/x was optimized for shaping a desired flat-topped radiation pattern. The planar array antenna designed in this paper has a rectangular lattice and is composed of array elements of 16${\times}$8. Each radiating element, which is a microstrip element fed coaxially, has a linear vertical polarization and the feed network which use a Wilkinson power divider and a 180$^{\circ}$ ring hybrid coupler as a base element is designed. The flat-topped radiation pattern with 90$^{\circ}$ is shaped by 16 array elements with the element spacing of 0.55 λ$_{ο}$ in the azimuth plane, and the normal radiation pattern with 10$^{\circ}$ is shaped by 8 array elements with the element spacing of 0.65 λ$_{ο}$ in the elevation plane. Also, the planar array antenna is symmetrically divided into four parts. It consists of one hundred-twenty-eight radiating elements, thirty-two 1-4 column dividers, low 1-8 row dividers and one 1-4 input power divider. In order to verify electrical performances of the planar way antenna proposed in this paper, the experimental breadboard operated in tile band of 1.92～2.17 GHz(IMT2000 band) was fabricated, and its experimental results were a good agreement with simulation ones.