• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2022년도 추계학술발표대회
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• pp.300-302
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• 2022

Palm vein identification has attracted attention due to its distinct characteristics and excellent recognition accuracy. However, many contactless palm vein identification systems suffer from the issue of having low-quality palm images, resulting in degradation of recognition accuracy. This paper proposes the use of U-Net architecture to correctly segment the vascular blood vessel from palm images. Attention gate mechanism and residual block are also utilized to effectively learn the crucial features of a specific segmentation task. The experiments were conducted on CASIA dataset. Hessian-based Jerman filtering method is applied to label the palm vein patterns from the original images, then the network is trained to segment the palm vein features from the background noise. The proposed method has obtained 96.24 IoU coefficient and 98.09 dice coefficient.

• Nuclear Engineering and Technology
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• 제56권10호
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• pp.4254-4262
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• 2024

Reinforced concrete structures are subject to exposure to chloride ions in the air, leading to chloride penetration, and carbonation attacks resulting from exposure to carbon dioxide. This chemical degradation process induces corrosion of reinforcing bars within concrete, significantly impacting durability. Structures situated in coastal areas, such as nuclear power plants, are particularly susceptible to rapid chloride penetration due to the high chloride concentration in the air. This study utilizes existing experimental data to forecast the chloride diffusion coefficient employing artificial neural network (ANN technology). The total number of experimental data was 535 gathered from 18 papers. Through analysis of the chloride coefficient and predicted degradation depth, the effective cross-sectional area of concrete is examined, and the deterioration of wall performance is forecasted.

• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.385-395
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• 2005

A finite element scheme is considered for the viscous Cahn-Hilliard equation with the nonconstant gradient energy coefficient. The scheme inherits energy decay property and mass conservation as for the classical solution. We obtain the corresponding error estimate using the extended Lax-Richtmyer equivalence theorem.

• 대기
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• 제26권4호
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• pp.673-686
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• 2016

Understanding limitation of simulation for Planetary Boundary Layer (PBL) height in mesoscale meteorological model is important for accurate meteorological variable and diffusion of air pollution. This study examined the accuracy for simulated PBL heights using two different PBL schemes (MYJ, YSU) in Weather Research and Forecasting (WRF) model during the radiosonde observation period. The simulated PBL height were verified using atmospheric sounding data obtained from radiosonde observations that were conducted during 5 months from August to December 2014 over the Gumi weir in Nakdong river. Four Dimensional Data Assimilation (FDDA) using radiosonde observation data were conducted to reduce error of PBL height in WRF model. The assessment result of PBL height showed that RMSE with YSU scheme were lower than that with MYJ scheme in the day and night time, respectively. Especially, the WRF model with YSU scheme produced lower PBL height than with the MYJ scheme during night time. The YSU scheme showed lower RMSE than the MYJ scheme on sunny, cloudy and rainy day, too. The experiment result of FDDA showed that PBL height error were reduced by FDDA and PBL height at the nudging coefficient of $3.0{\times}10^{-1}$ (YSU_FDDA_2) were similar to observation compared to the nudging coefficient of $3.0{\times}10^{-4}$ (YSU_FDDA_1).

• 한국물환경학회지
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• 제23권5호
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• pp.740-747
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• 2007

The advanced wastewater treatment plant of leather industry was selected to evaluated with its effluent water quality and statistical characteristics. Most of pollutants removal efficiencies were over 90% as well. And 95% reliability of effluent concentration were 106.8 mg/L of $COD_{mn}$, 72.04 mg/L of TN. However Effluent quality of TN exceeds the regulated limit. The range of coefficient of variation (CV) were between 0.18 and 2.49. Also, coefficient of reliability (COR) were between $0.03(BOD_5){\sim}0.63(COD_{mn})$ and 0.43 in terms of T-N, $Z_{l-a}$(Normalized Percentiles) value were 55.7 and 2.25 in terms of $BOD_5$ and T-N as shown in the following table.

• 한국전자파학회논문지
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• 제26권11호
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• pp.985-991
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• 2015

본 논문에서는 한반도 지역 내에서 안정적인 위성통신 서비스를 위한 최적의 망 이중화 지점을 제안한다. 이를 위해 기상청에서 측정한 88개 지점, 5년간의 강우량 데이터를 분석하였으며, 상관관계를 이용하여 두 지점간 강우가 동시에 발생할 확률 변화를 분석하였다. 국내 위성통신 관련 4개 주요 지점을 중심으로 강우 발생 상관도 변화를 등고선 맵으로 분석하였으며, 송신 지구국 이중화 지점으로 가장 적합한 지점/지역에 대한 정보를 제안하였다.

• 한국육종학회지
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• 제43권5호
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• pp.399-404
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• 2011

Genetic diversity among 28 Cymbidium varieties was evaluated by using a sequence-related amplified polymorphism (SRAP) marker system. The SRAP marker which was based on the open reading frames (ORFs) regions was developed primarily for Brassica species, but has been applied to various crops. A total of 30 SRAP primer combinations were initially screened. Twenty-eight SRAP primer combinations showed high polymorphism among the 28 Cymbidium varieties, which were consisted of breeding varieties and their parents in National Institute of Horticultural & Herbal Science (NIHHS). The amplified DNA fragments were separated by denaturing acrylamide gels and detected silver staining method. One hundred ninety six polymorphic bands (7 per primer) were generated and ranged from 0.3 to 1.0 kb in size. Polymorphic fragments were scored for calculating simple matching coefficient of genetic similarity and cluster analysis with multi-variate statistical package (MVSP) 3.1. The mean genetic similarity coefficient value was 0.588. The results showed that the correlation between $F_1$ varieties and their parents was high. These studied SRAP markers will be useful tools for genotype identification, germplasm conservation, genetic relationships in Cymbidium.

• 대한원격탐사학회지
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• 제39권6_1호
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• pp.1491-1495
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• 2023

본 연구는 북극의 해빙표면온도(ice surface temperature, IST)를 자동화된 기계 학습(automated machine learning, AutoML) 기반으로 산출하였다. AutoML 기반 IST는 상관관계(correlation coefficient, R) 0.97, 평균 제곱근 오차(root mean squared error, RMSE) 2.51K로 산출되었다. 심층신경망(deep neural network, DNN) 모델과 비교하여 AutoML IST는 Moderate Resolution Imaging Spectroradiometer (MODIS) IST 및 ice mass balance (IMB) buoy IST와의 검증 결과에서 좋은 정확도를 보인다. 이는 어려운 극지방 조건에서 IST 추정 정확도를 향상시키는 AutoML의 효과를 강조한다.

• 해양환경안전학회지
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• 제20권5호
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• pp.511-525
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• 2014

본 연구는 반폐쇄성 해역인 마산만을 대상으로 eco-hydrodynamic model을 이용하여 해역의 물리적 구조를 분석하여, 물리적 안정도를 나타내는 수직확산계수를 산정하고, 생태계 모델에 적용하여 그 타당성을 평가하는 것이다. 해역의 물리적 구조는 EFDC모델을 사용하여 구하였으며, 수직 확산계수는 수층간의 밀도차이가 커질수록 감소하도록 산정하였다. 산정된 수직 확산계수를 Stella프로그램을 이용하여 구축한 생태계모델에 적용하여, 용존산소 재현성으로 그 타당성을 평가하였다. 수직확산계수 변화를 추정하여 적용한 모델의 결과는 2008년의 $R^2$값은 0.529~0.700으로 나타났으며, 2009년 $R^2$값은 0.542~0.791로 나타났다. 계산값은 관측값과 유사한 경향을 나타내었으며, 만 내측의 빈산소수괴를 잘 재현하였다. 본 연구에서 적용된 수직확산계수는 해역의 밀도성층과 물리적 안정도를 의미하는데, 향후 폐쇄성 내만해역의 빈산소수괴 발생 예측에 유용하게 활용될 것으로 판단된다.

• Carbon letters
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• 제2권3_4호
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• pp.159-164
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• 2001

In this study, the effects of carbon black (CB) content and anodic oxidation treatment with $AgNO_3$ on positive temperature coefficient (PTC) behavior of CB/HDPE nanocomposites were investigated. Also, the addition of elastomer as a toughing agent was studied. The 20~50 wt% of CB, 0~5 wtt% of elastomer, and 1 wt% of $AgNO_3$-filled HDPE nanocomposites were prepared using the internal mixer in 60 rpm at $160{\circ}C$ and the compression-molded at $180{\circ}C$ for 10 min. As a result, the room temperature resistivity and PTC intensity of the composites were dependent, to a large extent, on the content of CB, addition of elastomer, and surface chemical properties that were controlled in the relative arrangements of the carbon black aggregates in a polymeric matrix. Moreover, the composites with relatively low room temperature resistivity and suitable PTC intensity could be achieved by treatment of $AgNO_3$. Consequently, it was noted that PTC effect was due to the deagglomeration or the breakage of the conductive networks caused by thermal expansion or crystalline melting of the polymeric matrix.