• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.115-125
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• 2014

We investigate dissociation of diatomic molecules and anions using density functional theory (DFT) and density-corrected density functional theory (DC-DFT). We scan the potential energy curve of CH, NH and NO neutral molecule and its anion with both DFT and DC-DFT (in form of Hartree-Fock DFT, HF-DFT) using various functionals. Using CCSD(T) results as reference, we perform the error decomposition scheme recently proposed by Kim et al. The results show while most neutrals are $functio{\acute{n}}al$ error $domi{\bar{n}}ating$ normal calculations, $CH^-$ and $NO^-$ anions are density-driven error dominating abnormal calculations. In case of $NH^-$, traditional DFT goes to a wrong dissociation limit indicating abnormality, but both HF-DFT and CCSD(T) results need further investigation due to the kinks on the curve.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.11-15
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• 2017

We present a study of transition metal compounds using density functional theory (DFT), and density-corrected density functional theory(DC-DFT). By replacing the self-consistent density with that obtained from Hartree-Fock calculation, i.e., HF-DFT, the abnormality driven by self-interaction error is removed in several important cases. We discuss when and how HF-DFT works by examining 3d orbital dimers using approximate functionals and by comparing the results from self-consistent-DFT and HF-DFT with experimental values.

• 한국음향학회지
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• 제3권2호
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• pp.30-34
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• 1984

본 논문에서는 인코히어런트광 매트릭스-벡터곱셈기를 이용하여 입력 데이터를 광학적으로 DFT 할 수 있는 방법을 연구하였다. DFT의 웨이팅함수를 매트릭스로 나타내어 본 논문에서 제시한 2 개의 성분 분할 방법을 이용하여 마스크상에 부호화하고 광매트릭스-벡터곱셈기내에 고정시켜서 입력 데이터와 광학적으로 곱하도록 하였다.

• 한국치위생학회지
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• 제1권2호
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• pp.213-225
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• 2001

Objectives: This study was taken to investigate factors related to dental caries in deciduous teeth of preschool children. Methods : this study was completed by oral examination on 623 kindergarten pupils and questionnaire on their mothers in Sangju city from April 1 to May 20, 2001. Study design is Cross-sectional Study. Results: The mean values for decayed teeth indexed(dt index), filled teeth index(ft index), and decayed and filled teeth index(dft index) was 2.46, 1.85, and 4.30 respectively. 2.05 for girl was significantly lower than 2.77 of boy in gender (p<0.01). As child ren got older, values were higher(0.7 and 2.84 of three years old, 1.6 and 4.01 of four, 2.42 and 5.02 of five) in ft and dft index(p<0.001). Also, Mother age was almost same, that is, 4.12 dft value for 30~34 years was smaller than 6.17 for above forties(p<0.001). 2.07 and 4.68 for mothers who graduated from high school were higher than 1.36 and 3.34 for university in the ft and dft index(p<0.05), that is, the more they had a high educational level, the lower they got a values. Value 2.76 for children who had non cariogenic food was lower than 5.11 for those who had cariogenic food in dft index(p<0.001). In dft index, 3.82 of children who have learned the education on oral health from mother frequently have lower than 45 of children who have never learned (p<0.05). The ft value of children who had a snack food with mother(1.29) was a smaller than children had it at out of home(1.97)(p<0.05). The variables related 10 dft index were children and mothers age, educational level, and kinds of snack food (p<0.05). Conclusion : This study reveals that younger girl, younger mother, higher educational level, and non cariogenic foods showed lower dft index.

• 대한화학회지
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• 제65권1호
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• pp.9-14
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• 2021

이 연구에서는 1기압 298 K 기체 상태에서 페난트렌에 두 개의 OH 라디칼이 연쇄적으로 작용하여 페난트렌이 분해되는 반응 과정을 B3LYP/6-31G(d,p) 기저함수를 사용하여 DFT 계산을 수행하였다. 계산 결과 두 개의 OH 라디칼이 연쇄적으로 페난트렌에 작용하는 경우에도 phenanthren-9-ol 생성 반응이 phenanthren-1-ol 생성 반응보다 유리할 것으로 예측된다. 한편 OH 첨가와 H 추출 과정에 대한 우선성은 상온에서 OH 첨가 과정이 유리할 것으로 예측되었다.

• 한국학교ㆍ지역보건교육학회지
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• 제12권2호
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• pp.69-80
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• 2011

Objectives: The purpose of this study was to explore relationship among dft index, diet and oral health behavior, parental awareness in oral health care and social status. Methods: This study was conducted from 8 January, 2009 to 11 June, 2009 in Asan city and Seosan city in Chungnam area. 4 kindergratens, 3 preschools and 1 children language academy were randomly selected to research on dft index, diet and oral health behavior. cross-sectional study conducted among 561 valid samples out of 641 samples collected using the survey was and then followed by oral examination. Throughout the research, numerus SPSS 15.0 statistical techniques, T-test and ANOVA and Spearman correlation coefficients were used for analysis. Results: Key results of the study are as follows: Age was found to be statistically very significant to dft index(p=0.036). Age of mother, especially between 30 to 49, was found to be statistically significant to dft index rate(p=0.001). Occupation of father was also found to be statistically significant to dft index(p=0.036). High parental awareness in oral health care led to low dft index rate, which also was found to be statistically significant(p=0.036). Conclusions: In conclusion, as Spearman correlation coefficient demonstrates, occupation of father affects most on long-term healthy oral behavior followed by parental awareness in oral health care and age of mother.

• 전기학회논문지P
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• 제57권2호
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• pp.102-108
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• 2008

AC generator plays an important role of power system. The large AC generator fault may lead to large impacts or perturbations in power system. And then the protection of a generator has very important role in maintaining stability in a power system. In present, the DFT(discrete Fourier transform) based RDR(ratio differential relay) had been widely applied to a internal fault of a generator stator winding. But DFT has a serious drawback. In the course of transforming a target signal to frequency domain, time information is lost. DWT uses a time-scale region. This paper proposes an advanced fault detection algorithm using DWT(discrete Wavelet transform) to enhance the drawback of conventional DFT based relaying. To evaluate the performance of the proposed relaying, we used the test data which were sampled with 720 [Hz] per cycle and obtained from ATP(alternative transient program) simulation. And we made a comparative study of conventional DFT based RDR and the proposed relaying.

• 한국통신학회논문지
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• 제35권8A호
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• pp.777-784
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• 2010

최근 수중 통신에 대한 관심이 급증하고 있으며, 수중 통신을 통한 음성 및 고해상도 영상 데이터와 같은 다양한 데이터 전송의 요구가 증가하고 있다. 수중 음향 통신 시스템의 성능은 수중 채널의 특성에 의해 크게 영향을 받으며, 특히 수중 채널 환경은 다중경로(Multi-path)에 따른 지연확산(delay spread)으로 인하여 데이터 전송 시 인접 심볼 간의 간섭(Inter Symbol interference: ISI)이 발생하여 통신의 성능을 저하시킨다. 본 논문에서는 지연 확산에 강한 성능을 나타내는 OFDM(Orthogonal Frequency Division Multiplexing) 기법을 수중 통신 시스템에 적용하고, OFDM의 CP(Cyclic Prefix)를 이용하여 수중 채널 환경의 다중경로로 인한 지연 확산을 보상한다. 하지만 수중 통신 시스템에 OFDM을 적용할 때, OFDM 시스템이 갖는 고유한 문제인 높은 PAPR(Peak-to-Average Power Ratio)이 발생한다. 그러므로 본 논문에서는 높은 PAPR로 인한 신호의 비선형 왜곡을 피하고 증폭기의 효율을 위하여 DFT-spread OFDM 기법을 적용한다. DFT-spread OFDM 방식은 IFFT 수행 이전에 DFT(discrete Fourier transform) 확산을 수행하여 각각의 병렬 데이터를 모든 부반송파들에 실어 줌으로써 좋은 PAPR 저감 효과를 얻는다. 그러므로 본 논문에서는 OFDM 시스템을 통해 수중 채널에서 지연 확산에 대한 성능 이득을 보이고, 일반적인 OFDM 시스템보다 DFT-spread OFDM이 수중 통신 환경에서 더 적합한 통신 방식임을 시뮬레이션을 통하여 보였다. 그리고 DFT-spread OFDM의 두 가지 자원 분배 방식(Interleaved, Localized)에 따른 성능을 분석하고 수중 통신 환경에서 자원 분배 방식에 따른 성능의 적응성에 대하여 논의하였다. 시뮬레이션 결과를 통해 CP 삽입을 통한 보상후의 BER 성능은 DFT-spread OFDM 방식이 일반 OFDM에 비하여 $10^{-4}$에서 약 5~6dB 정도 좋은 것을 보였으며, 자원 분배 방식에 따른 BER 성능을 비교하였을 때, Interleaved 방식은 Localized 방식에 비하여 $10^{-4}$에서 약 3.5dB 정도 좋은 것을 보였다.

• 인터넷정보학회논문지
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• 제4권3호
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• pp.31-37
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• 2003

본 논문에서는 유한상태머신을 위한 효율적인 비주사 DFT (design-for-testability) 기법을 제안한다. 제안된 기법은 순차회로 모델이 아닌 조합회로 모델을 사용한 ATPG를 수행하여 짧은 테스트 패턴 생성 시간과 완벽한 고장 효율을 보장한다. 또한 완전주사 기법이나 다른 비주사 DFT 기법에 비해 적은 면적 오버헤드를 보이며 테스트 패턴을 칩의 동작속도로 인가한다는 장점이 있다. 실험결과에서는 MCNC`91 벤치마크 회로를 이용하여 제안된 기법의 효율성을 입증한다.

• 통합자연과학논문집
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• 제15권4호
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• pp.187-194
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• 2022

Protein Arginine Methyltransferase 5 (PRMT5), a significant member of the PRMT family, is a promising anticancer target. In this study, novel small compounds that act against the PRMT5 target are found by combining virtual screening with ChEMBL database medicines and Density Functional Theory. The ChEMBL database compounds were screened to retrieve the hit molecules, which further subjected for DFT analysis. Finally we have evaluated that ChEMBL- approved drugs such as Lifitegrast, Abiraterone acetate and Solifenacin may be potential inhibitors for PRMT5.