• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.421-430
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• 2003

In this paper, we propose a method to consider SAR(Specific Absorption Rate) at beginning stage of handsets development. First, simulation was carried out with changing folding angle from 150$^{\circ}$to 142$^{\circ}$. Simulation results show that SAR value is decreased with decreasing the folding angle. When folding angle is 142$^{\circ}$, error between simulation and measurement results is about 3.95 %. Second, we made some experiments with EMI (Electromagnetic Interference) paint, and its results show that different pattern of EMI paint have different SAR values. After removing EMI paint at the lower part of antenna feeding point, we got the decrease efficiency of 15.46 % for SAR value. When we applied zigzag painting pattern, we got the highest SAR decrease efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.12
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• pp.1437-1450
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• 1992

This paper describes the feature extraction of the interdigital regions of palm, and proposes a personal verification algorithm using the extracted features and the pattern types of those. The procedures of the feature extraction are as follows : first, the interdigital region is partitioned into several subregions, examining the phase of rigdes in each subregion, deciding the direction of that phase, and making the direction matrix of the region, we analyze this direction matrix to contain a feature pattern, and then, yield the first core. Second, applying the thinning to around the first core and tracing the thinned ridges, we yield the feature pattern types and second cores. Finally, the feature patterns coordinates included all of them are built. Then, distances and directions from each second core reaching to all the others are yielded from that coordinates. These informations are used to make a feature parameter. In our verification algorithm, such pattern types, the numbers of feature patterns, theses positions and feature parameters are used to analyze.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.51-52
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• 2014

Non-destructive technique to measure internal structure and constant distribution of material can be widely used to exploration of mineral resources, identification of underground cables and buried pipelines, and diagnostic imaging in medical area. In this paper, we considered 2-dimensional EM scattering problem. Radiation pattern in far field is estimated by using some measured information obtained from near-field solutions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.6 s.360
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• pp.57-63
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• 2007

In this paper, a new approach to the optimum synthesis of line source difference patterns is proposed for the monopulse tracking way antennas. In the Proposed scheme, which is different from the well-known Bayliss difference pattern synthesis, the difference patterns with the desired individual sidelobe levels are optimally synthesized by appropriately modifying the Taylor line source sum pattern formula. That is, the relationship between the difference pattern and the corresponding source distribution function is analytically established, and then the desired pattern and the distribution are simultaneously extracted by the optimum perturbation of pattern null positions. Furthermore this method provides more rapid sidelobe decay rates than conventional methods. Some numerical results show the validity and usefulness of the proposed procedures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.49-55
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• 2019

This paper presents a marker image evaluation method based on analysis of object distribution in images and classification of images with repetitive patterns for effective marker-based augmented reality (AR) system development. We measure the variance of feature point coordinates to distinguish marker images that are vulnerable to occlusion, since object distribution affects object tracking performance according to partial occlusion in the images. Moreover, we propose a method to classify images suitable for object recognition and tracking based on the fact that the distributions of descriptor vectors among general images and repetitive-pattern images are significantly different. Comprehensive experiments for marker images confirm that the proposed marker image evaluation method distinguishes images vulnerable to occlusion and repetitive-pattern images very well. Furthermore, we suggest that scale-invariant feature transform (SIFT) is superior to speeded up robust features (SURF) in terms of object tracking in marker images. The proposed method provides users with suitability information for various images, and it helps AR systems to be realized more effectively.

• Journal of the Economic Geographical Society of Korea
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• v.5 no.1
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• pp.69-87
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• 2002

This study examines the spatial diffusion and locational charateristics of convenience stores in Daegu which had increased rapidly in the 1990s. The first convenience store (CVS) was introduced in the zone of transition of (Namgu district) adjacent to the city center or CBD in 1992. Thereafter they diffused into CBD and residential areas, but they have centered around places where their steady purchasing population was distributed. As a result, the spatial distribution of CVSs in Daegu shows a very uneven pattern concentrated in areas with many high school, in commercial and business areas, and apartment residential areas. It seems that this pattern is derived from two basic locational factors. Primarily, the location of CVSs in Daegu is very closely related with the spatial distribution of the demand population which will be clients for CVSs. Secondarily, it is also affected by the accessibility of streets which the demand population utilizes easily.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.712-714
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• 2003

서로 다른 형태와 크기를 가지는 탐색패턴과 움직임 벡터의 분포는 블록 정합 기법에서 탐색 속도와 화질을 좌우하는 중요한 요소이다. 본 논문에서는 납작한 육각패턴을 이용한 새로운 고속 블록 정합 알고리즘을 제안한다. 이 방법은 작은 육각패턴을 이용하여 적은 탐색점으로 움직임이 적은 벡터를 우선 찾은 다음에 움직임이 큰 벡터에 대해서는 납작한 육각패턴을 이용하여 고속으로 움직임 벡터를 찾게 하였다. 실험결과, 제안된 알고리즘은 육각패턴 탐색기법에 비하여 움직임 벡터 예측의 속도에 있어서 약 11~51% 이상의 높은 성능 향상을 보였으며 화질 또한 PSNR 기준으로 약 0.05~0.74dB 의 향상을 보였다.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.7
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• pp.495-502
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• 2013

Motion estimation (ME) that limits the performance of image quality and encoding speed has been developed to reduce temporal redundancy in video sequences and plays an important role in digital video compression. But it is computational demanding part of the encoder. Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. ME for Multi-view video requires high computational complexity. To reduce computational complexity and maintain the image quality, a fast motion estimation method is proposed in this paper. The proposed method uses a hierarchical search strategy. This strategy method consists of modified diamond search patten, multi gird diamond search pattern, and raster search pattern. These search patterns place search points symmetrically and evenly that can cover the overall search area not to fall into the local minimum or exploits the characteristics of the distribution of motion vectors to place the search points. Experiment results show that the speedup improvement of the proposed method over TZ search method (JMVC) can be up to 1.2 ~3 times faster while maintaining similar video quality and bit rates.

• Journal of the Korean Geographical Society
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• v.34 no.5
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• pp.473-491
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• 1999

세균성 이질은 국내 제1종 법정 전염병으로 분류되어 관리되고 있는 질환으로서 1998년 이후 그 발병 사례가 급속히 증가하고 있다. 본 연구는 1999년 3월 부산시 사상구에서 집단 발병한 세균성 이질을 대상으로 하여, 각 환자들의 발병 시점과 장소의 분포패턴에 대한 지리학적 고찰을 목적으로 한다. 환자분포의 특징적 공간패턴과 그들의 시계열적 확산 양상 등을 탐색하기 위한 방법론은 보건지리학과 지도학 및 공간통계학에 기반을 둔 공간분석기법을 중심으로 설정하였다. 분석자료는 해당 지역의 수치지형도, 지적도, 인구 센서스 자료를 포함한 GIS 데이터베이스로 구축되었다. 인구분포를 감안한 밀도구분도를 바탕으로 개별환자의 위치자료와 동 단위로 집계된 자료를 자료의 형태에 따라 분석기법을 달리하였으며, 환자 발생 밀도, 상대적 위험지수 등을 지도화하여 역학자료의 시각적 통계적 분석을 수행하였다. 환자분포의 공간적 중심위치와 분산의 변화 등 기술적 통계분석과 함께 제1차 공간속성을 커널추정법으로 찾아보았다. 이와 더불어 ‘공간적 의존성’과 관련된 제2차 공간속성은 K-함수와 시뮬레이션을 통해 분석하여 군집성 등이 통계적으로 확인되었다. 본 연구를 통해 역학조사시 GIS의 활용사례가 제시되었으며, 모집단 인구를 고려한 확률지도 작성 기법과 다양한 데이터 가시화 방법, 그리고 시계열별 발생 환자들의 지리적 변이를 분석 하는데 따르는 문제들이 논의되었다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.514-516
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• 2003

LCD(Liquid Crystal Display)는 자체 발광능력이 없으므로 그 후면에서 LCD 화면을 밝혀주는 BLU(Backlight Unit)를 필요로 한다. BLU의 핵심부품으로써 광원으로부터 나온 빛을 LCD의 패널 방향으로 이끌어내는 역할을 담당하고 있는 부분이 바로 도광판이고, 빛을 패널 방향으로 고르게 분포시키기 위해 도광판 하부에 점 모양의 확산물질을 인쇄한다. 이 인쇄패턴은 광원으로부터의 거리에 따라서 그 크기를 다르게 함으로써 패널 부분으로 균일한 평면광을 생성하도록 한다. 따라서 보다 균일한 평면광을 생성하는 BLU를 개발하기 위해서는 주어진 조건에서 패널 부분으로 균일한 평면광을 생성하도록 설계된 인쇄패턴을 찾는 것이 관건이다. 이러한 인쇄패턴을 Simplex Search 알고리즘을 사용하여 자동으로 찾게 함으로써 수작업으로 찾는 것보다 빠른 시간 내에 더욱 효율적인 인쇄패턴을 찾도록 한다.