• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.456-458
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• 2012

손 추적은 HCI 분야에 있어 손쉽게 이용 가능한 정보 전달 방식 중 하나이며 현재까지도 다양한 연구가 진행되고 있다. 이러한 연구의 공통점은 멀티 큐(Multi-cue)를 기반으로 추적한다는 것이다. 멀티 큐를 사용할 경우 큐들을 어떻게 효율적으로 결합하느냐에 따라 추적 성능이 달라진다. 본 논문에서는 강인한 손 추적을 위해 MSEPF(Mean Shift Embedded Particle Filter) 알고리즘에서 적응적인 멀티 큐 통합 방법을 제안한다. 이는 MSEPF 내부에서 각 파티클에 대한 가중치를 적용할 때, 큐들의 계수를 불확실성 기반으로 계산하여 사용하는 것으로 기존의 멀티 큐 통합 방식의 손 추적보다 강인한 추적을 가능하게 한다. 본 논문에서는 컬러, 깊이 정보에서 얻을 수 있는 피부색, 모션, 깊이 정보 기반 큐를 활용하여 손 추적을 수행하며, 실험 결과, 제안하는 방법은 갑작스런 환경 변화에도 강인한 성능을 보였다.

• Magazine of the Korea Concrete Institute
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• v.9 no.3
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• pp.179-187
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• 1997

콘크리트는 여러 구성 성분들이 불규칙적인 배열을 이루어 형성된 복합재료이지만, 과거에는 이 재료를 하나의 단종재료로 간주하여 해석하였기 때문에, LEFM에서 사용되는 파괴인성계수만으로는 콘크리트의 파괴역학적 접근이 어렵다는 것 이외에는 파괴인성계수들의 크기의존성에 대한 이유라든가, 실험을 통해서 관측된 구조물 두께 방향으로의 서로 다른 깊이의 균열 진행 현상에 대해서는 설명하기가 어려웠다. 따라서 본 연구는 콘크리트를 하나의 복합재료로써 각각의 구성요소들이 차지하고 있는 체적비 및 배열상의 효과를 고려하여 복합재료의 파괴거동을 해석하고, 구성재료의 수와 파괴인성계수와의 상관관계를 분석하였다. 각각의 구성요소들을 연립변형모드( SD mode)로 배열시킨 조건에서 복합재료역학개념에 입각하여 해석한 결과, 일반적으로 실험이나 비선형파괴역학 해석과 같이 하중-변위곡선 상단부에서 비선형 거동이 관측되었다. 또한 임계응력확대계수( $K_IC$)나 파괴에너지($G_r$)는 구성원의 수나 보의 크기에 대해서 거의 무관한 값을 나타내지만, 임계군열선단개구변위 ($CTOD_c$)는 크기에 영향을 받음을 보여 주었다. 균열의 진행속도는 균열이 진행될수록 감소하며, 파괴인성이 작은 구성원에서부터 균열이 발생되어 결과적으로 보의 두께 방향으로 서로 다른 크기의 균열길이가 생성됨이 관측되었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.651-663
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• 2017

Experimental results of $30^{\circ}-15^{\circ}$ nozzles were compared with numerically calculated convective heat transfer coefficients using FLUENT, Boundary Layer Integration Method and Bartz predictions. Also, the convective heat transfer coefficients were calculated by using FLUENT and boundary layer integration method for NASA HIPPO nozzles according to the characteristics of combustion gas and the correlation between pressure and pressure was compared. Finally, thermal analysis of NASA HIPPO nozzle was performed to compare the ablation thickness and char depth according to the combustion gas characteristics.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.316-316
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• 2012

본 연구에서는 국립환경과학원에서 체계화된 유역 및 하천환경 DB 구축을 통해 국내 모든 하천에 대한 수리 수문학적 기초자료를 표준화기 위해 만들고 있는 한국형 Reach File을 통하여 경안천 유역에 대해 QUAL2E 모형을 이용하여 수질모의 하고자 한다. 수질 모델링의 적용 사례를 살펴본 바에 따르면 하천을 모델링하기 위해서는 현장 특성 자료의 중요성, 특히 하천수리특성에 관련된 기초 자료의 가용성 여부가 모형의 성패에 매우 중요한 역할을 함을 알 수 있다. 유량, 유속 및 폭과 깊이로 대변되는 하천 지형은 물질 이송에 대한 주요 외력 함수이며, 다른 모든 예측치 들은 이들에 의존적일 수밖에 없다. 따라서 이들의 정확한 표현은 올바른 수질 예측에 있어서 필수적이다. 국립환경과학원에서 구축하는 한국형 Reach File에는 도형 및 속성자료를 설계하였을 뿐만 아니라, 각 수계별 주요하천에 대한 Reach별로 하상단면정보 및 수리계수를 DB화하여 관리하고 있기 때문에 대상 하천의 유량, 유속 및 수심자료를 일괄적으로 제공을 하고 있다. 본 연구에서는 한국형 Reach File을 통하여 경안천유역의 수질을 모의하였다. Reach File에는 경안천 유역의 Reach 별로 수리학적 특성인 하천연장, 하상경사, 조도계수, 수리계수등 QUAL2E 모델의 입력자료등을 제공해 줌으로써 수질모의 과정의 정량화 및 간편화를 가능하게 하였다. 또한 효율성 증대에 기여하는 바가 클 것으로 예상되며 2013년 6월부터 시행되는 한강수계 수질오염총량관리 의무제 시행과 관련하여 보다 과학적이고 정확한 모델링 결과 도출이 가능할 것으로 판단된다.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.199-208
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• 2016

$^{99}mTc-MAG_3$ Renal scan is a method that acquires dynamic renal scan image by using $^{99}mTc-MAG_3$ and dynamically visualizes process of radioactive agent being absorbed to kidney and excreted continuously. Once the test starts, ratio in both kidneys in 1~2.5 minutes was measured to obtain split renal function and split renal function can be expressed in ratio based on overall renal function. This study is based on compares split renal function obtained from data acquired from posterior detector, which is a conventional renal function test method, with split renal function acquired from the geometric mean of values obtained from anterior and posterior detectors, and studies utility of attenuation compensation depending on difference in geometric mean kidney depth. From July, 2015 to February 2016, 33 patients who undertook $^{99}mTc-MAG_3$ Renal scan(13 male, 20 female, average age of 44.66 with range of 5~70, average height of 160.40cm, average weight of 55.40kg) were selected as subjects. Depth of kidney was shown to be 65.82 mm at average for left and 71.62 mm at average for right. In supine position, 30 out of 33 patients showed higher ratio of deep-situated kidney and lower ratio of shallow-situated kidney. Such result is deemed to be due to correction by attenuation between deep-situated kidney and detector and in case where there is difference between the depth of both kidneys such as, lesions in or around kidney, spine malformation, and ectopic kidney, ratio of deep-situated kidney must be compensated for more accurate calculation of split renal function, when compared to the conventional test method (posterior detector counting).

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.11-22
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• 2023

In this work, a depth-by-depth evaluation on the deterioration of concrete is suggested by utilizing disk shaped concrete specimens. Dynamic elastic modulus of cylindrical concrete was measured using a free-free resonance column method and compared with dynamic elastic modulus of disk-shaped concrete measured by impulse excitation technique(IET) and impact resonance(IR). According to the results of the experiment, both IET and IR methods showed a smaller difference in dynamic elastic modulus with smaller deviation in data when thickness of the disk specimen was increased. This trend was more evident from dynamic elastic modulus measured by IR method compared to that measured by IET. Variation in data was also smaller with the IR result. To increase the accuracy of the data, it is recommended to use the IR method for disk specimen with a diameter of 100mm and a thickness of 25mm.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.2
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• pp.62-67
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• 2014

A glomerular filtration rate (GFR) study is a test that uses radioactive materials or tracers (radiopharmaceuticals) and a computer to see how well the kidneys are working. Asan Medical Center analyzed and compared data between kidney depth, acquired from kidney donors' CT image and acquired from Gates method's GFR value that are calculated by Tonnesen equation. This study was able to confirm that kidney depth measured from CT image was higher than the Gates Method's GFR value, which was calculated by Tonnessen equation; the direct relationship among pathologic results is confirmed. Particularly, kidney donor whose kidney was at the pelvic area had direct relationship with other clinical results. During the GFR test, it is necessary to confirm the location of kidney has no change with reference of CT image. If kidney depth is manually corrected using CT image when we measures GFR of deformed or horse-shoe kidney, it would be possible to acquire the compatible value which is equivalent to clinical result. There would be a possible issue of appropriateness that whether the applied GFR using CT image's kidney depth has clinical validity. In case of a pediatric patient, the GFR derived from Tonnesen was quiet underestimated while manual method and Gordon stay in normal range. Which results may be correct among them? There have been many reports about kidney depth, to be an accurate index of GFR in children. As one of the study performers, we should contemplate what the best option for pediatric patients would be.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.2
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• pp.119-128
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• 2008

In the case of a circular shaft, it is expected that asymmetric loads should apply on the surface rather than symmetric loads due to geographical factors and the non-homogeneity of the jointed rock masses. In this study, discontinuous numerical analysis was carried in order to analyze the characteristics of asymmetric load distribution on the wall of the circular shaft due to anisotropy caused by heterogeneity of rock masses affected by the discontinuities like as a Joint. And it was also analyzed that the effect of the mechanical properties varied with the rock mass rating and horizontal stress with depth had influence in the asymmetric load on the wall of the shaft. In the case of considering the effect of the joint as variable, asymmetric load ratio $(R_p)$, which was defined as the ratio of the load subtracted minimum from maximum to minimum, was below 25% in the hard rock. As regarding the variation of the rock mass rating with depth as variable, the value of $R_p$ was below than 25% in the hard rock, and the value between 30% and 40% in the soft rock. On the other hand, the $R_p$ of fractures rock was between $45{\sim}50%$ which value was much higher than that in better rock mass rating.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.2 s.48
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• pp.51-62
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• 2006

In the companion paper (I-Problem Statements of the Current Seismic Design Code), the current Korean seismic design code is required to be modified considering site characteristics in Korea for the reliable estimation of site amplification. In this paper, three site classification methods based on the mean shear wave velocity of the top 30m $V_{S30}$, fundamental site periods $(T_G)$ and bedrock depth were investigated and compared with each other to determine the best classification system. Not enough of a difference in the standard deviation of site coefficients $(F_a\;and\;F_v)$ to determine the best system, and neither is the difference between the average spectral accelerations and the design response spectrum of each system. However, the amplification range of RRS values based on $T_G$ were definitely concentrated on a narrow band than other classification system. It means that sites which have a similar behavior during earthquake will be classified as the same site category at the site classification system based on $T_G$. The regression curves between site coefficients and $T_G$ described the effect of soil non linearity well as the rock shaking intensity increases than the current method based on $V_{S30}$. Furthermore, it is unambiguous to determine sue category based on $T_G$ when the site investigation is performed to shallower depth less than 30m, whereas the current $V_{S30}$ is usually calculated fallaciously by extrapolating the $V_s$ of bedrock to 30m. From the results of this study, new site classification system based on $T_G$ was recommended for legions of shallow bedrock depth in Korea.

• Journal of the Korean Geotechnical Society
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• v.32 no.4
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• pp.5-14
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• 2016

Numerical simulation of dynamic soil-pile-structure interaction embedded in a dry sand was carried out. 3D model of the dynamic centrifuge model tests was formulated in a time domain to consider nonlinear behavior of soil using the finite difference method program, FLAC3D. As a modeling methodology, Mohr-Coulomb criteria was adopted as soil constitutive model. Soil nonlinearity was considered by adopting the hysteretic damping model, and an interface model which can simulate separation and slip between soil and pile was adopted. Simplified continuum modeling (Kim et al., 2012) was used as boundary condition to reduce analysis time. Calibration process for numerical modeling results and test results was performed through the parametric study. Verification process was then performed by comparing numerical modeling results with another test results. Based on the calibration and validation procedure, it is identified that proposed modeling method can properly simulate dynamic behavior of soil-pile system in dry condition.