• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.160-161
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• 2010

본 논문에서는 컬러 정보와 형태 정보를 이용한 상표 영상 검색 시스템을 제안하였다. 컬러 정보는 영역을 분할하여 영역별 컬러 분포 히스토그램 특성에 근거한 컬러 정보를 이용하였고, 형태 정보는 경계면 추출, 무게 중심 추출, angular 샘플링 등의 전처리 과정과 무게 중심으로부터 경계면까지 거리의 합, 표준 편차, 장/단축 비율을 계산을 이용하였다. 특히, 무게중심을 이용한 angular 샘플링을 이용하여 특징을 추출하고 처리 시간을 줄일 수 있었다. 사용자는 컬러와 형태 정보에 의한 검색을 수행하고, 또한 가중치를 부여함으로써 두 방법을 혼합하여 사용할 수 있다.

• 한국운동역학회지
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• 제16권4호
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• pp.21-30
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• 2006

The purpose of the study is to search for the possibility of the application of kinematics analysis to physical education at schools and expand its scope of application. This study chose 9 college students majoring in physical education and classified them into type A group who can make the straight, vertical handstand, type B group whose waist is bent, type C group who cannot handstand completely. The center of mass, distance between hand and leg, and the angle and angular velocity of each joint were obtained. The result of this study is this. 1. The time for CM showed 6:4 for A group and 5:5 for B and C groups. The distance between hand and foot in the event 3 was 44% of the height for A group, and 41% for B and C groups. A Group showed the higher CM positional significant difference, it was vertically direction below the hip joint at front. For significant difference of the B Group showed horizontal and vertical velocity of the CM, the highest vertical was obtained in phase 3. The difference of angle of shoulder join in the flexion/extension was showed gradually extension event 2 and the height angular velocity was at phase 3 in the A group. 2 The analysis of the handstand motion revealed that the phase 3, but the maintenance of posture start part the handstand is also very important. Through these results, this study confirmed that the time for phase of the CM, horizontal and vertical positions, velocity, the distance between hands and foot, and the difference of the angle and angular velocity of hip joint and shoulder joint can be set as the variables of analysis. It was also definite cause that the handstand motions of college students majoring in physical education had many difference in performance.

• 한국터널지하공간학회 논문집
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• 제15권5호
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• pp.469-481
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• 2013

워터젯 절삭기술을 이용한 자유면 생성에 있어서, 생성된 자유면 내부의 모니터링은 효율적인 작업 진행을 위해서 매우 중요하다. 본 연구에서는 레이저 센서를 이용하여 자유면 측정 실험을 수행하고 실질적 현장적용을 위한 변수의 영향 정도와 최적변수 범위를 제시하였다. 영향을 미치는 변수를 레이저의 분해각(angular resolution), 측정 이격거리(measurement distance), 그리고 자유면의 절삭형상(cutting shape)으로 나누어 실험 수행 및 결과 분석을 하였다. 그 결과 분해각과 측정 이격거리가 감소할수록 그리고 절삭 폭이 증가할수록 보다 정밀한 모니터링이 가능함을 확인할 수 있었다. 본 레이저 측정 시스템을 이용하면 자유면 형상과 깊이의 측정이 실제 현장에서 충분히 적용 가능할 것으로 판단된다.

• 한국의학물리학회지:의학물리
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• 제27권3호
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• pp.105-110
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• 2016

Sparse angular sampling has been studied recently owing to its potential to decrease the radiation exposure from computed tomography (CT). In this study, we investigated the analytic reconstruction algorithm in sparse angular sampling using the sinogram interpolation method for improving image quality and computation speed. A prototype of the spectral CT system, which has a 64-pixel Cadmium Zinc Telluride (CZT)-based photon-counting detector, was used. The source-to-detector distance and the source-to-center of rotation distance were 1,200 and 1,015 mm, respectively. Two energy bins (23~33 keV and 34~44 keV) were set to obtain two reconstruction images. We used a PMMA phantom with height and radius of 50.0 mm and 17.5 mm, respectively. The phantom contained iodine, gadolinium, calcification, and lipid. The Feld-kamp-Davis-Kress (FDK) with the sinogram interpolation method and Maximum Likelihood Expectation Maximization (MLEM) algorithm were used to reconstruct the images. We evaluated the signal-to-noise ratio (SNR) of the materials. The SNRs of iodine, calcification, and liquid lipid were increased by 167.03%, 157.93%, and 41.77%, respectively, with the 23~33 keV energy bin using the sinogram interpolation method. The SNRs of iodine, calcification, and liquid state lipid were also increased by 107.01%, 13.58%, and 27.39%, respectively, with the 34~44 keV energy bin using the sinogram interpolation method. Although the FDK algorithm with the sinogram interpolation did not produce better results than the MLEM algorithm, it did result in comparable image quality to that of the MLEM algorithm. We believe that the sinogram interpolation method can be applied in various reconstruction studies using the analytic reconstruction algorithm. Therefore, the sinogram interpolation method can improve the image quality in sparse-angular sampling and be applied to CT applications.

• 소성∙가공
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• 제10권4호
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• pp.302-310
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• 2001

The twisting and extrusion process of the product with involute helical fin from the round billet is developed by the upper bound analysis. The twisting of extruded product is caused by the twisted inclined die surface connecting the die enterance section and the die exit section linearly. In the analysis, the internal shear surface is defined as the curved twisted plane from the twisting of die surface and the shear work is calculated by the consumption of shear energy. The increase rate of angular velocity is determined by the minimization of plastic work. The angular velocity of die exit can be controlled by the land length and the length of inclined die. The alular velocity assums to be increased linearly by the axial distance from the die enterance to the die exit. The results of the analysis show that the angular velocity of the extruded product increases with the die twisting angle, the reduction of area, and decreases with the die length, the friction constant.

• 한국수산과학회지
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• 제44권4호
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• pp.423-430
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• 2011

The most satisfactory split-beam transducer for fish sizing maintains a wide bearing angle region for correct fish tracking without interference from side lobes and lower sensitivity to fish echoes outside of the main lobe region to correctly measure the angular location of free-swimming fishes in the sound beam. To evaluate the performance of an experimentally developed 50 kHz split-beam transducer, the angular location of a target was derived from the electrical phase difference between the resultant signals for the pair of transducer quadrants in the horizontal and vertical planes consisting of 32 transducer elements. The electrical phase difference was calculated by cross-spectral density analysis for the signals from the pair of receiving transducer quadrants, and the directivity correction factor for a developed split-beam transducer was estimated as the fourth-order polynomial of the off-axis beam angle for the angular location of the target. The experimental results demonstrate that the distance between the acoustic centers for the pair of receiving transducer quadrants can be controlled to less than one wavelength by optimization with amplitude-weighting transformers, and a smaller center spacing provides a range of greater angular location for tracking of a fish target. In particular, a side lobe level of -25.2 dB and an intercenter spacing of $0.96\lambda$($\lambda$= wavelength) obtained in this study suggest that the angular location of fish targets distributing within a range of approximately ${\pm}28^{\circ}$ without interference from side lobes can be measured.

• 한국게임학회 논문지
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• 제13권6호
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• pp.27-34
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• 2013

본 논문은 동물들의 집단행동에서 나타나는 포식자-희생자 관계에서 포식자에 대한 희생자의 추격회피 행동을 분석한다. 희생자가 포식자의 추격을 피하는 하나의 방법이 인접거리에서 급회전을 하는 것이다. 그때 희생자가 추격으로부터 살아남기 위해서는 임계거리와 회전각은 매우 중요하다. 여기서 임계거리는 회전 시작 직전 포식자와 희생자 사이의 거리이다. 이러한 임계거리와 회전각을 분석하기 위하여 본 논문은 추격의 시작에서 보유한 포식자의 에너지와 추격동안 소비한 포식자의 에너지를 이용한다. 시뮬레이션을 통하여, 임계거리가 짧을수록 희생자가 추격으로부터 살아남을 수 있는 회전각은 커진다는 것과 포식자의 질량에 대한 희생자의 질량의 비율이 작아지는 경우에도 역시 회전각 커진다는 것을 알 수 있었다. 시뮬레이션 결과는 자연에서 나타나는 현상과 유사하며, 따라서 이것은 본 논문에서 분석한 방법이 옳다는 것을 의미한다.

• 한국컴퓨터정보학회논문지
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• 제11권3호
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• pp.167-172
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• 2006

영상 검색 시스템이란 영상이 갖는 다양한 특징을 바탕으로 똑같거나 유사한 영상을 검색하여 제공하는 시스템이다. 본 논문에서는 영상의 컬러와 형태를 기반으로 한 상표 영상 검색 시스템을 제시한다. 영상을 영역별로 분할하고 영역별 컬러 분포 히스토그램을 추출하여 컬러 정보로 이용한다. 경계면 추출, 무게 중심 추출, angular 샘플링 등의 전처리 과정과 무게 중심으로부터 경계면 까지 거리의 합, 표준 편차, 장/단축 비율을 계산하여 형태정보로 이용한다. 이렇게 추출된 컬러와 형태 정보를 이용하여 유사성 측정을 통한 검색을 수행한다.

• Journal of Information Processing Systems
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• 제15권4호
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• pp.737-747
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• 2019

Shape description is an important and fundamental issue in content-based image retrieval (CBIR), and a number of shape description methods have been reported in the literature. For shape description, both global information and local contour variations play important roles. In this paper a new included-angular ternary pattern (IATP) based shape descriptor is proposed for shape image retrieval. For each point on the shape contour, IATP is derived from its neighbor points, and IATP has good properties for shape description. IATP is intrinsically invariant to rotation, translation and scaling. To enhance the description capability, multiscale IATP histogram is presented to describe both local and global information of shape. Then multiscale IATP histogram is combined with included-angular histogram for efficient shape retrieval. In the matching stage, cosine distance is used to measure shape features' similarity. Image retrieval experiments are conducted on the standard MPEG-7 shape database and Swedish leaf database. And the shape image retrieval performance of the proposed method is compared with other shape descriptors using the standard evaluation method. The experimental results of shape retrieval indicate that the proposed method reaches higher precision at the same recall value compared with other description method.

• 한국운동역학회지
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• 제13권1호
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• pp.139-153
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• 2003

The purpose of the study was to present technical guidance about the field goal kicking motion in American football for novices. For this purpose, kinematic analysis on the field goal kicking motion of two skilled players and two unskilled players was carried out. The following conclusions were made: 1. In comparison on the total elapsed time of the kicking, there were no significant differences between two groups. The progressing time from BP event to impact among experts group, however, took 0.141 second less than that of novices group. 2. The experts group showed right hip rotatier horizontally toward the targeted ball fixing left hip as the axis. On the other hand, the novices group didn't use the left hip as the axis in the kicking motion. 3. At the impact of kicking the ball, regarding with the distance of the ball and the supporting leg, the right and left distance of experts was 3.45cm longer than that of novices, the front and the rear distance of experts was 5.14cm shorter than novices. 4. At the impact, experts' initial velocity of the targeted ball was $5.27^m/s$ faster than novices', besides experts' incidence angular displacement was $3.78^{\circ}$ larger than novices'. 5. After BP event, experts showed a stable movement maintaining flexion and extension at left hip joint and knee joint. On the other hand, for novices, the angle of the left lower extremities became larger. 6. Experts showed the efficient flexion and extension of the hip joint and the knee joint during following procedure in the whole event of the kicking motion. At the BP event, the right knee joint angle of novices was $11.46^{\circ}$ larger than that of experts. However, the duration of the impact event and FT event among, novices had less extension of knee joint than experts. 7. At the 2nd phase, for both of the groups, the angular velocity of the knee joint drastically increased as the angular velocity of hip joint decreased. However, only novices showed the largest negative angular velocity at the impact.