• 한국전문물리치료학회지
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• 제27권3호
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• pp.199-205
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• 2020

Background: The classification of foot type can be commonly determined by the height of the media longitudinal arch. The normalized arch height (NAH) is defined as the ratio of navicular or instep heights to the foot length or instep length. Objects: This study investigated the relationships among foot characteristics, such as foot length (FL), instep length (IL), navicular height (NH), and instep height (IH), in Korean young adults. Also, the distribution of foot type based on calculated NAH was assessed. Methods: Three-dimensional foot scanning data of young adults aged 20 to 39 years (total: 1,978; 974 male, 1,004 female) were obtained from the Korea Technology Standards Institute, and used for analyses. NAH was calculated as the following: NH/FL, IH/FL, IH/IL, NH/IL. Spearman's rank order correlation was used to identify correlations among variables. The Mann-Whitney U-test and chi-square test were used to compare the sex differences in foot characteristics and distribution of foot type. Results: FL and IL showed a very high correlation (r = 0.94). The correlations between FL or IL and IH (r = 0.50-0.57) were greater than those between FL or IL and NH (r = 0.23-0.72). Males had significantly larger values than females (p < 0.001), and the frequency of pes planus was significantly higher in females than in males (χ² = 50.09, p < 0.001). Based on the IH/IL index, the neutral foot, pes planus and pes cavus distributed by 16%, 78%, and 6% respectively. Conclusion: Our results on foot arch distribution could be used as basic data in clinical or footwear fields, and our data on differences in arch structure according to sex may facilitate understanding of why injury to the lower limbs differs between males and females.

• Journal of Ecology and Environment
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• 제41권2호
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• pp.34-44
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• 2017

Background: Monitoring terrestrial vegetation cover condition is important to evaluate its current condition and to identify potential vulnerabilities. Due to simplicity and low cost, point intercept method has been widely used in evaluating grassland surface and quantifying cover conditions. Field-based digital photography method is gaining popularity for the purpose of cover estimate, as it can reduce field time and enable additional analysis in the future. However, the caveats and uncertainty among field-based vegetation cover estimation methods is not well known, especially across a wide range of cover conditions. We compared cover estimates from point intercept and digital photography methods with varying sampling intensities (25, 49, and 100 points within an image), across 61 transects in typical steppe, forest steppe, and desert steppe in central Mongolia. We classified three photosynthetic groups of cover important to grassland ecosystem functioning: photosynthetic vegetation, non-photosynthetic vegetation, and bare soil. We also acquired normalized difference vegetation index from satellite image comparison with the field-based cover. Results: Photosynthetic vegetation estimates by point intercept method were correlated with normalized difference vegetation index, with improvement when non-photosynthetic vegetation was combined. For digital photography method, photosynthetic and non-photosynthetic vegetation estimates showed no correlation with normalized difference vegetation index, but combining of both showed moderate and significant correlation, which slightly increased with greater sampling intensity. Conclusions: Results imply that varying greenness is playing an important role in classification accuracy confusion. We suggest adopting measures to reduce observer bias and better distinguishing greenness levels in combination with multispectral indices to improve estimates on dry matter.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2919-2922
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• 2003

In this paper, we present a new methodology to analyze the characteristics of artery by using 4 channels photophethysmography. The proposed parameter is a time difference of pulse transit time (PTT) between pulse waves at finger site and at toe site. As the results of experiments, the change of parameter was found according to ages. The result of regression analysis about relationships between the parameter and ages for n=51, the coefficient of correlation of non-normalized data has -0.79770 in left side and -0.80599 in right side and the coefficient of correlation of normalized data by height has -0.81345 in left side and -0.81605 in right side.

• IEIE Transactions on Smart Processing and Computing
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• 제4권1호
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• pp.1-9
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• 2015

Template matching is used for many applications in image processing. One of the most researched topics is object tracking. Normalized Cross Correlation (NCC) is the basic statistical approach to match images. NCC is used for template matching or pattern recognition. A template can be considered from a reference image, and an image from a scene can be considered as a source image. The objective is to establish the correspondence between the reference and source images. The matching gives a measure of the degree of similarity between the image and the template. A problem with NCC is its high computational cost and occasional mismatching. To deal with this problem, this paper presents an algorithm based on the Sum of Squared Difference (SSD) and an adaptive template matching to enhance the quality of the template matching in object tracking. The SSD provides low computational cost, while the adaptive template matching increases the accuracy matching. The experimental results showed that the proposed algorithm is quite efficient for image matching. The effectiveness of this method is demonstrated by several situations in the results section.

• 제어로봇시스템학회논문지
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• 제16권9호
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• pp.913-917
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• 2010

To inspect the defects of printed markings on the surface of IC package, the OCV (Optical Character Verification) method based on NCC (Normalized Correlation Coefficient) pattern matching is widely used. In order to detect the micro pattern defects appearing on the small portion of the markings, a Partitioned NCC pattern matching method was proposed to overcome the limitation of the NCC pattern matching. In this method, the reference pattern is first partitioned into several blocks and the NCC values are computed and are combined in these small partitioned blocks, rather than just using the NCC value for the whole reference pattern. In this paper, we proposed a method to decide the proper number of partition blocks and a method to inspect and combine the NCC values of each partitioned block to identify the defective markings.

• 방송공학회논문지
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• 제16권4호
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• pp.614-623
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• 2011

본 논문에서는 방송용 증강현실 시스템을 위한 실시간 카메라 추적 알고리듬을 제안한다. SURF(speeded up robust features) 알고리듬을 이용하여 추적을 초기화하며, 안정적인 실시간 카메라 추적을 위해 다층(multi-scale) 구조를 사용한다. 미리 알려져 있지 않고 시간에 따라 변하는 조명 환경에서의 특징 추적을 위해 정규상호상관도(normalized cross correlation, NCC)를 사용한다. 방송제작에는 줌 렌즈를 장착한 카메라가 사용되기 때문에 카메라의 초점거리를 온라인으로 추정할 필요가 있다. 카메라의 회전과 이동으로 이루어진 외부 포즈(pose) 변수와 함께 내부 변수인 초점거리를 목적함수에 포함시켜 함께 최적화한다. 실험결과는 제안한 온라인 카메라 보정 기법에 의해 카메라의 초점거리가 정확히 구해지는 것을 보여준다.

• Journal of information and communication convergence engineering
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• 제9권2호
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• pp.201-206
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• 2011

FRUC (Frame Rate Up-Conversion) technique needs an effective frame interpolation algorithm using motion information between adjacent neighboring frames. In order to have good visual qualities in the interpolated frames, it is necessary to develop an effective detection and interpolation algorithms for occluded regions. For this aim, this paper proposes an effective occluded region detection algorithm through the adaptive forward and backward motion searches and also by introducing the minimum value of normalized cross-correlation coefficient (NCCC). That is, the proposed scheme looks for the location with the minimum sum of absolute differences (SAD) and this value is compared to that of the location with the maximum value of NCCC based on the statistics of those relations. And, these results are compared with the size of motion vector and then the proposed algorithm decides whether the given block is the occluded region or not. Furthermore, once the occluded regions are classified, then this paper proposes an adaptive interpolation algorithm for occluded regions, which still exist in the merged frame, by using the neighboring pixel information and the available data in the occluded block. Computer simulations show that the proposed algorithm can effectively classify the occluded region, compared to the conventional SAD-based method and the performance of the proposed interpolation algorithm has better PSNR than the conventional algorithms.

• 소성∙가공
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• 제27권2호
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• pp.115-122
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• 2018

Most domestic and international standards on the forming limit diagram (FLD) including ISO 12004-2, use a 'position-dependent method,' which determines the forming limit from a strain distribution measured on the specimen after necking or fracture. However, the position-dependent method has inherent problems such as the incidence of asymmetry of a strain distribution, the estimation of missing data near fracture, the termination time of test, and the deformation due to the new stress equilibrium after a fracture, which is blamed for causing sometimes a significant lab-to-lab variation. The 'time-dependent method,' which is anticipated to be a new international standard for evaluating the forming limit, is expected to greatly improve these intrinsic disadvantages of the position-dependent method. It is because the time-dependent method makes it possible to identify and accurately determine the forming limit, just before the necking point from the strain data as continuously measured in a short time interval. In this study, we propose a new time-dependent method based on a Gaussian fitting of strain acceleration with the introduction of 'normalized correlation coefficient.' It has been shown in this study that this method can determine the forming limit very stably and gives a higher value, which is in comparison with the results of the previously studied position-dependent and time-dependent methods.

• 대한전자공학회논문지SD
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• 제38권9호
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• pp.616-623
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• 2001

회절격자의 인접한 반주기 길이 사이에 음의 상관관계가 있는 반주기 길이의 랜덤 변이가 QWS-DFB 레이저의 주모드 파장 분포에 미치는 영향을 유효 굴절률 전달 매트릭스 방법으로 알아보았다. 주모드 파장 분포를 쉽게 파악할 수 있도록 주모드 파장 분포를 회절격자 반주기의 정규화된 표준편차 σΛ와 인접 반주기 랜덤 변이 사이의 상관계수 γ 의 해석적인 근사식으로 나타내었다. 이 확률 밀도 함수는 가우스 분포 함수이며, 그 표준편차는 σΛ가 커질수록 커지고 γ가 -1로 갈수록 작아진다.

• 한국콘텐츠학회논문지
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• 제10권3호
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• pp.1-9
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• 2010

본 논문에서는 모바일 환경에서 모션을 추정하기 위하여 특징점을 코너로 선택하고, 기존 코너 검출 알고리즘인 Rosten 알고리즘 보다 모션 추정의 정확성을 높이는 방법을 제안한다. Rosten 알고리즘은 간단한 덧셈과 뺄셈만으로 코너를 검출함에 따라 처리 속도가 빠른 장점이 있지만, 코너를 매칭하면서 모션추정의 성능이 떨어지는 단점을 가지고 있다. 우리는 Normalized Cross Correlation(NCC) 계수를 사용하여 코너를 매칭하고, 두 단계에 걸쳐 부정확한 매칭에 의한 외톨이를 제거한다. 기존의 Rosten 알고리즘과 제안하는 알고리즘을 실제 영상에서 실험을 통하여 성능을 비교하고, 실제 모바일 장치의 응용 프로그램에 적용한다. 제안한 알고리즘이 Rosten 알고리즘 보다 더 정확한 모션을 추정해 냄을 실험 결과 확인하였고, 실제 모바일 환경에서도 실시간으로 동작함을 확인하였다.