• 한국지능시스템학회논문지
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• 제19권4호
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• pp.485-492
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• 2009

모바일 서비스 환경에서 시간 동기화에 의해 생성된 패턴들은 데이터 스트리밍으로 인하여 인스턴스 값들이 다르게 스트리밍 된다. 본 논문에서는 유연한 클러스터링을 지원하기 위해 가변클러스터링 관리 기법을 제안하며, 이 구조는 다중 데이터 스트리밍을 동적으로 관리하도록 지원한다. 제안되는 기법은 일반적인 스트리밍기법과 달리 데이터 스트림 환경에서 동기화를 효율적으로 지원하는 기능을 수행하며, 구조적 표현단계와 적합성 표현단계를 거쳐 클러스터링 스트리밍이 관리된다. 구조적 표현 단계는 레벨정합과 누적정합을 수행하여 스트림 구조가 표현되며, 동적 세그먼트와 정적세그먼트 관리를 통해서 클러스터링 관리가 가변적으로 수행되도록 하였다. 제안된 기법의 성능 평가를 위해서 k-means 기법, C/S 서버기법 그리고 CDN 기법과 시뮬레이션평가를 수행하였으며 그 결과 제안된 기법의 성능이 효율적임을 알 수 있었다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권1_2호
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• pp.98-113
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• 2002

본 논문에서는 블록 정합 알고리즘(BMA: block matching algorithm)인 다단계 연속 제거 알고리즘(MSEA: multi-level successive elimination algorithm)[1]의 연산량을 줄이기 위하여 네 가지 방안을 제안하였다. 첫 번째 제안 방안은 MSEA에서 서브 블록(sub block)의 합 놈(sum norm)에 대한 절대 오차의 합(SAD: sum of absolute difference)을 계산할 때 부분 왜곡 제거(PDE: partial distortion elimination) 기법을 적용하여 연산량을 감소시킨 알고리즘이다. 두 번째 제안 방안인 적응 SAD 계산 알고리즘은 SAD 계산 시 절대 오차가 큰 값에서부터 작은 값의 순으로 SAD를 계산하면 PDE가 빨리 발생하게 되어 연산량을 줄일 수 있는 성질을 이용한 알고리즘이다. 세 번째 제안 방안인 제거 레벨 추정 알고리즘은 탐색점의 제거 레벨을 추정하고 추정된 레벨에서부터 상위 레벨로 다단계 연속 제거 과정을 수행함으로 추정된 제거레벨보다 낮은 레벨들과 연관된 연산량을 감소시킨 알고리즘이다. 제안된 첫 번째, 두 번째, 세 번째 방안은 움직임 추정의 정확도가 전역 탐색 알고리즘(FSA: full search algorithm) 및 MSEA와 동일하면서 MSEA의 연산량을 효과적으로 감소시킨 알고리즘들이다. 네 번째 제안 방안인 나선형 다이아몬드 그물 탐색 알고리즘은 움직임 추정의 정확도가 거의 100%이면서 움직임 추정에 필요한 연산량을 획기적으로 감소시킨 고속 블록 정합 알고리즘이다. 위의 네 가지 제안 방안에 대한 성능을 평가하기 위하여 실험을 수행하였으며 실험에서 제안 방안들의 효율성을 확인하였다.

• 한국지형공간정보학회:학술대회논문집
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• 한국지형공간정보학회 2004년도 추계학술발표대회 논문집
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• pp.25-31
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• 2004

항공사진을 이용하여 도로의 3차원 위치정보를 취득하기 위해서는 도로지역에 대한 정확한 매칭 기법이 필요하다. 본 연구에서는 도로 노면표식의 형상정보와 공간관계를 이용하여 도로 노면표식을 추출하고, 추출된 노면표식의 공간관계를 비교하여 입체항공영상에서 매칭을 수행하는 즉, 관계형 매칭 기법을 제안하였다. 관계형 매칭은 개체에 대한 고수준의 묘사와 부정확한 매칭에 대한 해결책이 요구되어 진다. 또한 최종 결과물에 대한 충분한 검증을 필요로 한다. 본 연구에서는 도로 노면표식의 형상정보를 계산하여 개체를 묘사하였고, 부정확한 매칭에 대한 해결책을 제안하였으며, 도로지역이 평평하다는 성질을 이용하여 최종결과에 대한 검증을 수행하였다. 본 연구의 정확도는 시각적인 평가와 수치사진 측량시스템을 통해 얻은 참고자료와의 비교를 통해 수행하였다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2006년도 춘계학술발표회 논문집
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• pp.181-185
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• 2006

Image co-registration is the process of overlaying two images of the same scene, one of which represents a reference image, while the other is geometrically transformed to the one. In order to improve efficiency and effectiveness of the co-registration approach, the author proposed a pre-qualified area matching algorithm which is composed of feature extraction with canny operator and area matching algorithm with cross correlation coefficient. For refining matching points, outlier detection using studentized residual was used and iteratively removes outliers at the level of three standard deviation. Throughout the pre-qualification and the refining processes, the computation time was significantly improved and the registration accuracy is enhanced. A prototype of the proposed algorithm was implemented and the performance test of 3 Landsat images of Korea showed: (1) average RMSE error of the approach was 0.436 Pixel (2) the average number of matching points was over 38,475 (3) the average processing time was 489 seconds per image with a regular workstation equipped with a 3 GHz Intel Pentium 4 CPU and 1 Gbytes Ram. The proposed approach achieved robustness, full automation, and time efficiency.

• 대한치과보철학회지
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• 제16권1호
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• pp.38-44
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• 1978

Color is an important factor in dental esthetics. Application of natural tooth color will not fail to produce pleasing results. But a standardized method of shade matching has not been adopted. If we are to overcome the color matching problem in dentistry, an understanding of the nature of color and light is essential. The purpose of this study was to compare the effects of different light sources and different background colors on the ability of observers to correctly match shades of artifical teeth. And observation was made to determine if the time spent in making a shade match was a factor in the correctness of the response. A test method was devised and 50 individuals made observations which were recorded and analyzed. $X^2$-test gave results indicating that the time factor had no effect on the response made. An analysis of variance showed the following effects significant at the five percent level; (1) light source (2) background color (3) subject. The following conclusions can be drawn from this study; (1) The time spent in making shade selection is not a factor in the correctness of the selections. (2) The light source used is an important factor in matching tooth shade; and there is no significant difference between the light sources in shade matching. (3) Under the conditions of this study, the greatest accuracy in shade matching was obtained on the brown background.

• 대한원격탐사학회지
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• 제18권3호
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• pp.181-186
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• 2002

One of the most important procedure in stereo DEM generation is the stereo matching process which finds the conjugate pixels in a pair of stereo imagery. In order to be found as conjugate pixels, the pixels should have distinct spatial feature to be distinguished from other pixels. However, in the homogeneous areas such as water covered or forest canopied areas, it is very difficult to find the conjugate pixels due to the lack of distinct spatial feature. Most of erroneous elevation values in the stereo DEM are produced in those homogeneous areas. This paper presents a simple method for improving the quality of stereo DEM utilizing the texture filters. An entropy filter was applied to one of the input stereo imagery to extract very homogeneous areas before stereo matching process. Those extracted homogeneous areas were excluded from being candidates for stereo matching process. Also a statistical texture filter was applied to the generated elevation values before the interpolation process was applied in odor to remove the remaining anomalous elevation values. Stereo pair of SPOT level 1B panchromatic imagery were used for the experiments. The results showed that by utilizing the texture filters as a pre and a post processor of stereo matching process, the quality of the stereo DEM could be dramatically improved.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권8호
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• pp.2366-2380
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• 2024

In this study, a high-speed template matching system is proposed for wafer-vision alignment. The proposed system is designed to rapidly locate markers in semiconductor equipment used for wafer-vision alignment. We optimized and implemented a template-matching algorithm for the high-speed processing of high-resolution wafer images. Owing to the simplicity of wafer markers, we removed unnecessary components in the algorithm and designed the system using a field-programmable gate array (FPGA) to implement high-speed processing. The hardware blocks were designed using the Xilinx ZCU104 board, and the pyramid and matching blocks were designed using programmable logic for accelerated operations. To validate the proposed system, we established a verification environment using stage equipment commonly used in industrial settings and reference-software-based validation frameworks. The output results from the FPGA were transmitted to the wafer-alignment controller for system verification. The proposed system reduced the data-processing time by approximately 30% and achieved a level of accuracy in detecting wafer markers that was comparable to that achieved by reference software, with minimal deviation. This system can be used to increase precision and productivity during semiconductor manufacturing processes.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2005년도 GIS/RS 공동 춘계학술대회
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• pp.345-349
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• 2005

Massive amount of satellite image processing such asglobal/continental-level analysis and monitoring requires automated and speedy georegistration. There could be two major automated approaches: (1) rigid mathematical modeling using sensor model and ephemeris data; (2) heuristic co-registration approach with respect to existing reference image. In case of ETM+, the accuracy of the first approach is known as RMSE 250m, which is far below requested accuracy level for most of satellite image processing. On the other hands, the second approach is to find identical points between new image and reference image and use heuristic regression model for registration. The latter shows better accuracy but has problems with expensive computation. To improve efficiency of the coregistration approach, the author proposed a pre-qualified matching algorithm which is composed of feature extraction with canny operator and area matching algorithm with correlation coefficient. Throughout the pre-qualification approach, the computation time was significantly improved and make the registration accuracy is improved. A prototype was implemented and tested with the proposed algorithm. The performance test of 14 TM/ETM+ images in the U.S. showed: (1) average RMSE error of the approach was 0.47 dependent upon terrain and features; (2) the number average matching points were over 15,000; (3) the time complexity was 12 min per image with 3.2GHz Intel Pentium 4 and 1G Ram.

• 보건교육건강증진학회지
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• 제33권1호
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• pp.61-70
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• 2016

Objectives: It has been well documented that people on the lower socioeconomic position are significantly more likely to smoke cigarettes. The purposes of this study were (a) to identify a potential difference of socioeconomic factors, and (b) to compare a smoking rate, one of the most representative health behavior between people with/without disabilities after the controlling socioeconomic factors. Methods: The Korea Panel Survey of Employment for People of Disabilities (2012) and the Korea National Health and Nutrition Survey (2012) were employed for calculating the smoking rates of persons with/without disabilities. Results: The results demonstrated that the socioeconomic position indicators (education, occupation and household equivalent income) of persons with disabilities were lower than persons without disabilities. The smoking rates of the persons with/without disabilities were 35.9% and 19.0% respectively before propensity score matching. After propensity score matching with the socioeconomic factors, however, ATT of people with disabilities was 0.201 which is lower than ATT of people without disabilities (0.227). Conclusions: Our findings indicated that the socioeconomic level of persons with disabilities is important to improve the smoking rates and health level regardless of their disabilities.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제3권2호
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• pp.43-46
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• 2014

시계열 데이터는 시간에 따라 변화되는 실수 값을 저장한 것이다. 시계열 데이터에서 사용자 질의 시퀀스가 주어졌을 때, 유사한 서브시퀀스를 가지는 데이터 시퀀스를 검색하는 서브시퀀스 매칭은 매우 중요한 문제이다. 본 논문에서는 인스턴스 레벨의 새로운 서브시퀀스 매칭 방법인 I-Match (Instance-Match)를 제안한다. I-Match는 인스턴스 레벨에서 가상 윈도우를 생성하여 질의 시퀀스와 데이터 시퀀스를 비교하여 착오 해답을 줄이는 방법으로 기존 방법인 Dual Match에 비해 후보의 개수를 줄임으로써 성능을 향상시켰다. 실험을 통해 I-Match의 질의 처리 시간이 Dual Match와 비교하여 최대 2.95배 빠르며, 후보의 개수를 줄임을 보인다.