• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.258-258
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• 2018

In this study, a hydraulic flow model and an error correction model are combined to improve the flood simulation accuracy. First, the hydraulic flow model is calibrated by optimizing the Manning's roughness coefficient that considers spatial and temporal variability. Then, an error correction model were used to correct the systematic errors of the calibrated hydraulic model. The error correction model is developed using Artificial Neural Networks (ANNs) that can estimate the systematic simulation errors of the hydraulic model by considering some state variables as inputs. The input variables are selected using parital mutual information (PMI) technique. It was found that the calibrated hydraulic model can simulate flood water levels with good accuracy. Then, the accuracy of estimated flood levels is improved further by using the error correction model. The method proposed in this study can be used to the flood control and water resources management as it can provide accurate water level eatimation.

• Structural Engineering and Mechanics
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• 제55권6호
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• pp.1099-1120
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• 2015

External prestressing has been applied to both new construction and retrofitting of existing reinforced and prestressed concrete structures. Continuous beams are preferred to simply supported beams because of economy, fewer movement joints and possible benefits from moment redistribution. However, this paper argues that continuous prestressed concrete beams with external unbonded tendons demonstrate different full-range behaviour compared to reinforced concrete (RC) beams. Applying the same design approach for RC to external prestressing may lead to design with a lower safety margin. To better understand the behaviour of continuous prestressed concrete beams with unbonded tendons, an experimental investigation is performed in which nine such specimens are tested to failure. The full-range behaviour is investigated with reference to moment-curvature relationship and moment redistribution. The amounts of moment redistribution measured in the experiments are compared with those allowed by BS 8110, EC2 and ACI 318. Design equations are also proposed to estimate the curvature ductility index of unbonded prestressed concrete beams.

• 대한수학회논문집
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• 제34권2호
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• pp.543-555
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• 2019

In this paper, we give some results on ${\frac{zf^{\prime}(z)}{f(z)}}$ for the certain classes of holomorphic functions in the unit disc $E=\{z:{\mid}z{\mid}<1\}$ and on ${\partial}E=\{z:{\mid}z{\mid}=1\}$. For the function $f(z)=z^2+c_3z^3+c_4z^4+{\cdots}$ defined in the unit disc E such that $f(z){\in}{\mathcal{A}}_{\alpha}$, we estimate a modulus of the angular derivative of ${\frac{zf^{\prime}(z)}{f(z)}}$ function at the boundary point b with ${\frac{bf^{\prime}(b)}{f(b)}}=1+{\alpha}$. Moreover, Schwarz lemma for class ${\mathcal{A}}_{\alpha}$ is given. The sharpness of these inequalities is also proved.

• 로봇학회논문지
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• 제16권1호
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• pp.64-71
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• 2021

This paper describes a robotic teleoperation system to perform an accurate needle insertion into a cornea for a separation between the stromal layer and Descemet's membrane during deep anterior lamellar Keratoplasty (DALK). The system can reduce the hand tremor of a surgeon by scaling the input motion, which is the control input of the slave robot. Moreover, we utilize corneal applanation to estimate the insertion depth. The proposed system was validated by performing the layer separation using 25 porcine eyes. The average depth of needle insertion was 742 ± 39.8 ㎛ while the target insertion depth was 750 ㎛. Tremor error was reduced from 402 ± 248 ㎛ in the master device to 28.5 ± 21.0 ㎛ in the slave robot. The rate of complete success, partial success, and failure were 60, 28, and 12%, respectively. The experimental results showed that the proposed system was able to reduce the hand tremor of surgeons and perform precise needle insertion during DALK.

• Kyungpook Mathematical Journal
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• 제62권3호
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• pp.467-484
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• 2022

In this work, we define bivariate Bernstein-Kantorovich type operators on a triangular domain and obtain some approximation results for these operators. We start off by computing some moment estimates and prove a Korovkin type convergence theorem. Then, we estimate the rate of convergence using the partial and complete modulus of continuity, and derive a Voronovskaya-type asymptotic theorem. Further, we calculate the order of approximation with regard to the Peetre's K-functional and a Lipschitz type class. In addition, we construct the associated GBS type operators and compute the rate of approximation using the mixed modulus of continuity and class of the Lipschitz of Bögel continuous functions for these operators. Finally, we use the two operators to approximate example functions in order to compare their convergence.

• Structural Engineering and Mechanics
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• 제82권2호
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• pp.133-149
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• 2022

This study investigates the resistance of sustainable ultra-high performance concrete (UHPC) on steel reinforcement corrosion. For enhancing the sustainability of UHPC, concrete mixes were prepared with ordinary Portland cement main binder, and mixes with moderate to high percentages of blast furnace cement (CEM III), fly ash (FA), and slag cement as partial replacements of the full quantity of the used cement. Linear polarization resistance technique was employed to estimate the electrochemical behavior of the concrete specimens. Results showed that the compressive strength and the resistance of steel to corrosion in marine environments can be enhanced by improving the sustainability of UHPC through incorporation of CEM III, FA, and slag cement. FA replacement of up to 50% with the addition of 15% SF content produced better compressive strength and steel corrosion resistance than slag cement whether with the use of ordinary Portland cement or blast furnace cement as the main binder.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2031-2036
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• 2022

Energetic particle strikes the device and induces data corruption in the configuration memory (CRAM), causing errors and even malfunctions in a system on chip (SoC). Software-based fault injection is a convenient way to assess device performance. In this paper, dynamic partial reconfiguration (DPR) is adopted to make fault injection on a Xilinx 16 nm FinFET Ultrascale+ MPSoC. And the reconfiguration module implements the Sobel and Gaussian image filtering, respectively. Fault injections are executed on the static and reconfiguration modules' bitstreams, respectively. Another contribution is that the failure modes and effects analysis (FMEA) method is applied to evaluate the system reliability, according to the obtained injection results. This paper proposes a software-based solution to estimate programmable device vulnerability.

• 분석과학
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• 제37권1호
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• pp.12-24
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• 2024

In this study, laser-induced breakdown spectroscopy (LIBS) was used to estimate the degree of rice polishing. As-threshed rice seeds were dehusked and polished for different times, and the resulting grains were analyzed using LIBS. Various atomic, ionic, and molecular emissions were identified in the LIBS spectra. Their correlation with the amount of polished-off matter was investigated. Na I and Rb I emission line intensities showed linear sensitivity in the widest range of polished-off-matter amount. Thus, univariate models based on those lines were developed to predict the weight percent of polished-off matter and showed 3-5 % accuracy performances. Partial least squares-regression (PLS-R) was also applied to develop a multivariate model using Si I, Mg I, Ca I, Na I, K I, and Rb I emission lines. It outperformed the univariate models in prediction accuracy (2 %). Our results suggest that LIBS can be a reliable tool for authenticating the degree of rice polishing, which is closed related to nutrition, shelf life, appearance, and commercial value of rice products.

• Asian-Australasian Journal of Animal Sciences
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• 제33권10호
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• pp.1633-1641
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• 2020

Objective: The objective of this study was to develop a model for estimating the carcass weight of Hanwoo cattle as a function of body measurements using three different modeling approaches: i) multiple regression analysis, ii) partial least square regression analysis, and iii) a neural network. Methods: Data from a total of 134 Hanwoo cattle were obtained from the National Institute of Animal Science in South Korea. Among the 372 variables in the raw data, 20 variables related to carcass weight and body measurements were extracted to use in multiple regression, partial least square regression, and an artificial neural network to estimate the cold carcass weight of Hanwoo cattle by any of seven body measurements significantly related to carcass weight or by all 19 body measurement variables. For developing and training the model, 100 data points were used, whereas the 34 remaining data points were used to test the model estimation. Results: The R² values from testing the developed models by multiple regression, partial least square regression, and an artificial neural network with seven significant variables were 0.91, 0.91, and 0.92, respectively, whereas all the methods exhibited similar R² values of approximately 0.93 with all 19 body measurement variables. In addition, relative errors were within 4%, suggesting that the developed model was reliable in estimating Hanwoo cattle carcass weight. The neural network exhibited the highest accuracy. Conclusion: The developed model was applicable for estimating Hanwoo cattle carcass weight using body measurements. Because the procedure and required variables could differ according to the type of model, it was necessary to select the best model suitable for the system with which to calculate the model.

• 한국지반공학회논문집
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• 제32권9호
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• pp.17-27
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• 2016

서해안의 인천 및 화성지역에 분포하는 모래 및 실트 함유량이 많은 저소성 지반에 대해 피에조콘관입시험(CPTU) 데이터 및 강제치환 공법을 이용하여 부분배수 특성을 분석하였다. Powell과 Quarterman(1988)에 의한 과압밀비 $OCR={\kappa}(q_t-{\sigma}_{vo})/{\sigma}^{\prime}_{vo})$ 경험식은 모래함유량이 많은 서해안 저소성 실트 지반에서는 상대적으로 투수성이 커서 표준관입속도(2cm/s)하에서 콘관입저항력($q_t$)이 크게 평가되어 과압밀비가 크게 산정되는 경향을 나타냈다. Schnaid et al. (2004)는 간극수압계수($B_q$)-강도증가율($s_u/{\sigma}^{\prime}_{vo}$)-정규화된 콘저항($Q_t=(q_t-{\sigma}_{vo})/{\sigma}^{\prime}_{vo}$)을 함께 도시하여, 부분배수 유무를 판단하도록 제시하였는데, 인천 및 화성 지역의 CPTU 데이터의 50% 이상이 부분배수 상태를 나타내는 $B_q$ < 0.3에 분포하였다. 또한, 강제치환 시공과정 중 부분배수 현상으로 인해 원지반의 강도증가 현상이 발생되어 설계 예상 치환깊이보다 훨씬 작은 실측값이 얻어진다는 관점에서 실측 치환깊이와 동일한 값이 얻어지도록 원지반의 지지력에 대한 역해석을 수행하였다. 그 결과, 소성지수가 감소할수록 내부마찰각이 커지는 경향을 나타내며, 내부마찰각(${\varphi}^{\prime}$)이 $2{\sim}7^{\circ}$의 범위에서 분포하는 것으로 분석되었다.