• 한국산업융합학회 논문집
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• 제22권4호
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• pp.387-394
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• 2019

This paper presents an analytical study on the strength and stiffness of various types of truss structures. The applied models are triangular-like opened truss-wall triangular model (OTT), closed truss-wall triangular model (CTT), opened solid-wall triangular model (OST), and hypercube models defined as core-filled or core-spaced cube. The models are analyzed by numerical model analysis using DEFORM 2D/3D tool with AISI 304 stainless steel. Then, the ideal solutions for stiffness and strength are defined. Finally, the relative elastic modulus of the core-spaced model is obtained as 0.0009, which is correlated with the cancellous bone for the relative density range of 0.029-0.03, and the relative elastic modulus for the core-filled model is obtained as 0.0015, which is correlated with cancellous bone for the relative density range of 0.035-0.036. For the relative compressive yield strength, the OTT reasonably agrees with the cancellous bone for the relative density of 0.042 and the relative compressive strength of 0.05. The CTT and OST are in good agreement at the relative density of 0.013 and the relative compressive yield strength of 0.002. The hypercube models can be used for the cancellous bone for stiffness, and the triangular models can be used for the cancellous bone for strength. However, none of the models can be used to replace the compact bone because it requires much higher stiffness and strength. In the near future, compact bone replacement must be further studied. In addition, previously mentioned models should be developed further.

• 한국도로학회논문집
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• 제18권2호
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• pp.91-101
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• 2016

PURPOSES : The aim of this study was to compare the performance of the QUEENSOD method and the gravity model in estimating Origin-Destination (O/D) tables for a large-sized microscopic traffic simulation network. METHODS : In this study, an expressway network was simulated using the microscopic traffic simulation model, VISSIM. The gravity model and QUEENSOD method were used to estimate the O/D pairs between internal and between external zones. RESULTS: After obtaining estimations of the O/D table by using both the gravity model and the QUEENSOD method, the value of the root mean square error (RMSE) for O/D pairs between internal zones were compared. For the gravity model and the QUEENSOD method, the RMSE obtained were 386.0 and 241.2, respectively. The O/D tables estimated using both methods were then entered into the VISSIM networks and calibrated with measured travel time. The resulting estimated travel times were then compared. For the gravity model and the QUEENSOD method, the estimated travel times showed 1.16% and 0.45% deviation from the surveyed travel time, respectively. CONCLUSIONS : In building a large-sized microscopic traffic simulation network, an O/D matrix is essential in order to produce reliable analysis results. When link counts from diverse ITS facilities are available, the QUEENSOD method outperforms the gravity model.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1604-1612
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• 2011

We developed three-dimensional quantitative structure activity relationship (3D-QASR) models for 17 adamantyl derivatives as P-glycoprotein (P-gp) inhibitors. Eighteen different partial charge calculation methods were tested to check the feasibility of the 3D-QSAR models. Best predictive comparative molecular field analysis (CoMFA) model was obtained with the Austin Model 1-Bond Charge Correction (AM1-BCC) atomic charge. The 3D-QSAR models were derived with CoMFA and comparative molecular similarity indices analysis (CoMSIA). The final CoMFA model ($q^2$ = 0.764, $r^2$ = 0.988) was calculated with an AM1-BCC charge and electrostatic parameter, whereas the CoMSIA model ($q^2$ = 0.655, $r^2$ = 0.964) was derived with an AM1-BCC charge and combined steric, electrostatic, hydrophobic and HB-acceptor parameters. Leave-five-out (LFO) cross-validation was also performed, which yielded good correlation coefficient for both CoMFA (0.801) and CoMSIA (0.656) models. Robustness of the developed models was checked further with 1000 run bootstrapping analyses, which gave an acceptable correlation coefficient for CoMFA (BS-$r^2$ = 0.997, BS-SD = 0.003) and CoMSIA (BS-$r^2$ = 0.996, BS-SD = 0.018).

• 대한전자공학회논문지TE
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• 제42권2호
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• pp.23-28
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• 2005

본 논문에서는 밀리미터파 대역의 주파수를 실시간으로 이루어지는 차량간 통신시스템에 적용하기 위해 전파경로 분석과 전파경로손실 예측 모델을 제안하였다. 다중경로에 의한 반사파의 영향을 분석하기 위해 차량정체가 많은 대도시 지역 편도 2차선의 도로에서 차량과 차량 사이에 통신이 이루어지는 경우를 가정하였다. 제안모델의 시뮬레이션 결과, 전파직선경로 100[m]를 진행하는 동안 반사파에 의한 전파경로는 직접파에 비해 0.1[m]$\sim$5.1[m]정도 더 길었다. 또한 전파경로 손실을 비교한 결과 벽면에 의한 반사의 경우 -0.8[dB]$\sim$-4.2[dB], 차량에 의한 반사의 경우 -0.8[dB]$\sim$-1[dB] 정도 더 손실이 커짐을 알 수 있었다. 이상의 결과 벽면에 의해 발생한 반사파의 경로손실이 인접 차량에 의해 발생한 경로 손실 보다 -3.2[dB] 정도 더 큼을 알 수 있었다.

• 한국임상수의학회지
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• 제19권3호
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• pp.290-294
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• 2002

The frequencies of gamma-ray-induced micronuclei (MN) in cytokinesis-blocked (CB) lymphocytes at several doses were measured in three donors of Korean native cattle and Korean native goat. Measurements performed after irradiation showed a dose-related increases in MN frequency in each of the donors studied. When analysed by linear-quadratic model the line of best fit was cattle : y : 0.1016D +$0.0118D^2$+0.0147, goat : y = 0.1353D +$0.0043D^2$+0.0087 (y : number of MN/CB cells and D = irradiation dose in Gy). The relative sensitivity of goat lymphocytes compared with cattle lymphocytes was estimated by best fitting linear-quadratic model based on the radiation-induced MN data over the range from 0 Gy to 4 Gy. In the case of MN frequency with 0.05, 0.1, 0.2, 0.4 and 0.8, the relative sensitivities of goat lymphocytes were 1.106. 1.166. 1.140, 1.069 and 0.976 respectively. Our in vitro radiobiological study confirmed that the cytogenetic response obtained in blood from cattle and goat can be utilized for application in environmental studies.

• 한국멀티미디어학회논문지
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• 제23권3호
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• pp.402-411
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• 2020

Power line noise in electrocardiogram signals makes it difficult to diagnose cardiovascular disease. ECG signals without power line noise are needed to increase the accuracy of diagnosis. In this paper, it is proposed DNN(Deep Neural Network) model to remove the power line noise in ECG. The proposed model is learned with noisy ECG, and clean ECG. Performance of the proposed model were performed in various environments(varying amplitude, frequency change, real-time amplitude change). The evaluation used signal-to-noise ratio and root mean square error (RMSE). The difference in evaluation metrics between the noisy ECG signals and the de-noising ECG signals can demonstrate effectiveness as the de-noising model. The proposed DNN model learning result was a decrease in RMSE 0.0224dB and a increase in signal-to-noise ratio 1.048dB. The results performed in various environments showed a decrease in RMSE 1.7672dB and a increase in signal-to-noise ratio 15.1879dB in amplitude changes, a decrease in RMSE 0.0823dB and a increase in signal-to-noise ratio 4.9287dB in frequency changes. Finally, in real-time amplitude changes, RMSE was decreased 0.3886dB and signal-to-noise ratio was increased 11.4536dB. Thus, it was shown that the proposed DNN model can de-noise power line noise in ECG.

• Communications for Statistical Applications and Methods
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• 제12권3호
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• pp.545-556
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• 2005

Hjort(1990) obtained the nonparametric Bayes estimator $\^{F}_{c,a}$ of $F_0$ with respect to beta processes in the random censorship model. Let $X_1,{\cdots},X_n$ be i.i.d. $F_0$ and let $C_1,{\cdot},\;C_n$ be i.i.d. G. Assume that $F_0$ and G are continuous. This paper shows that {$\^{F}_{c,a}$(u){\|}0 < u < T} converges weakly to a Gaussian process whenever T < $\infty$ and $\~{F}_0({\tau})\;<\;1$.

• 한국환경과학회지
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• 제30권8호
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• pp.613-619
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• 2021

Soil water enters the atmosphere via evapotranspiration, where it transforms into atmospheric water vapor and plays important role in the surface-atmosphere energy exchange. Soil conditions have a direct influence on the effective rainfall, and initial soil moisture conditions are important for quantitatively evaluating the effective rainfall in a watershed. To examine the sensitivity of the initial saturation to hydrologic outflow, a two-dimensional distributed FLO-2D hydrologic model was applied to a small watershed. The initial saturation was set to 0.3, 0.5, and 0.7 and the obtained results were compared. The Green-ampt model was chosen to calculate the penetration loss. Depending on the initial soil moisture, the peak flow rate varied by up to 60%, and the total water volume in the watershed by approximately 40%.

• 기술혁신학회지
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• 제11권1호
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• pp.72-90
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• 2008

기술혁신이 경제성장에 미치는 영향은 어떠한가? 이는 전통적으로 지식스톡을 반영하는 성장회계법에 의해 분석되었다. R&D에 대한 수익률 추정은 특허와 같은 R&D 산출이 지식축적에서 기인하는 것으로 파악한다. Griliches(1973)는 이를 위해 회귀분석 방법을 사용하였다. 본 연구에서는 기존 성장회계법에서의 추정방법과 달리 R&D 효율성을 나타내는 파라미터가 시간이 지남에 따라 변동(time-varying)하는 것을 허용하는 상태공간 모형(state-space model)을 통해 한국경제의 R&D 효율성(fertility)을 추정하였다. R&D 스톡의 생산성에 대한 탄력성은 $0.120{\sim}0.135$ 정도로 추정되었다.

• 대한화장품학회지
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• 제40권4호
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• pp.383-390
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• 2014

기질 분자로서 2-[(2,6-dioxocyclohexyl)methyl]cyclohexane-1,3-dione 유도체(1-23)들의 분자 내 치환기($R_1$ 및 $R_2$)가 변화함에 따른 tyrosinase 수용체의 저해활성에 관한 2D-QSAR 모델로부터 다음과 같은 결론을 얻었다. 유도된 최적의 2D-QSAR 모델은 $Obs.pI_{50}=-0.295({\pm}0.031)TDM$ $-0.120({\pm}0.014)DMZ+0.135({\pm}0.050)DMX$. $R_2+6.382({\pm}0.17)$이었으며, 예측성($q^2=0.843$)보다는 상관성($r^2=0.905$)이 큰 모델이었다. Tyrosinase 저해활성은 TDM > $DMX.R_2{\geq}DMZ$ 순으로 영향을 미치었으며, 기질분자의 소수성(ClogP > 0)이 크고, $R_1$-치환기의 입체적 크기가 클수록 더욱 증가하는 경향을 나타내었다. 모델을 분석한 결과, 분자 내 $R_2$-치환기 상 X-축 성분의 쌍극자능률($DMX.R_2$)이 클수록, 그리고 분자 전체의 쌍극자능률(TDM; Total Dipole Moment)과 Z-성분의 쌍극자능률(DMZ; Dipole Moment of Z-Component)이 작을수록 기질분자의 tyrosinase 저해활성이 높아짐을 암시하였다. 따라서 tyrosinase 저해활성은 기질분자 및 $R_2$-치환기의 전자 친화력에 기인한 것으로 예상되었다. 그러므로 저해활성을 증가시키려면 분자 내 극성 그룹을 소수성에 기여하는 비극성 작용기로 대체함이 바람직할 것으로 예측되었다.