• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2192-2195
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• 2003

This parer proposes a power-line phase measurement algorithm which is based on the recursive implementation of sliding-DFT. Usage of the single DFT coefficient in the conventional sliding-DFT based power-line phase measurement brings a significant error propagation when implemented in hardware with finite word-length arithmetic operations. The proposed algorithm utilizes all the N-point DFT coefficients in the recursion. Performance degradation caused by the finite word- length implementation of the algorithm is analyzed and verified with computer simulations. The robustness of the proposed phase measurement algorithm against the erroneous implementation is also confirmed by the performance analysis and simulation.

• 대한전자공학회논문지SD
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• 제41권2호
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• pp.55-65
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• 2004

본 논문에서는 레지스터 전송 수준의 데이터패스를 위한 효율적인 비주사 DFT 기법을 제안하였다. 데이터패스를 위해 제안된 비주사 DFT 기법은 레지스터 전송 수준(RTL : register transfer level) 회로에 대한 계층적 테스트 용이도(hierarchical testability) 분석을 통해 테스트 용이도를 향상시킴으로써 최소의 하드웨어 오버헤드를 가지고 데이터패스 버스 폭의 변화와 관계없이 항상 높은 고장 효율과 빠른 테스트 패턴 생성 시간을 보장한다. 실험 결과를 통하여 제안된 기법이 주사 기법보다 테스트 패턴 생성 시간, 테스트 패턴 적용 시간, 면적 오버헤드 면에서 우수함을 확인하였다.

• 한국음향학회지
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• 제18권8호
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• pp.48-53
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• 1999

본 논문에서는 Sliding-DFT(sliding discrete Fourier transform : SDFT)를 순환구조로 구현할 때 복소수 계수를 유한한 비트로 근사 표현하여 생기는 오차영향을 해석적으로 구하는 방법을 제시하고 유도 과정을 기술하였다. 해석한 결과는 오차전력과 신호전력 비(noise-to-signal power ratio : NSR)의 식으로 얻었으며, DFT 대상신호가 평균이 ‘0’인 가우스 백색신호(zero-mean white Gaussian signal)인 것으로 가정하였다. NSR 식은 복소수계수를 표현하는 비트 수와 DFT 구간길이에 대한 식으로 구하였다. 유도 과정은 SDFF 순환 식(recursive equation)으로 유도한 오차방정식(error dynamic equation)과 계수근 사오차의 공간적인 확률분포특성에 근거하였다. 해석적으로 유도한 NSR 결과를 시뮬레이션 실험을 통해 얻은 결과와 비교하여 타당성을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.309-312
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• 2013

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1998-2004
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• 2012

We carried out DFT calculations for monohydrated sulfuric and phosphoric acids. We are interested in clusters which differ in orientation of hydrogen atoms only. Such molecular complexes are close in energy, since they lie in the vicinity of the global minimum energy structure on the flat potential energy surface. For monohydrated sulfuric acid we identified four different isomers. The monohydrated phosphoric acid forms five different conformers. These systems are difficult to study from the theoretical point of view, since binding energy differences in several cases are very small. For each structure, we calculated harmonic vibrational frequencies to be sure that if the optimized structures are at the local or global minima on the potential energy surface. The analysis of calculated -OH vibrational frequencies is useful in interpretation of infrared photodissociation spectroscopy experiments. We employed four different DFT functionals in our calculations. For each structure, we calculated binding energies, thermodynamic properties, and harmonic vibrational frequencies. Our analysis clearly shows that DFT approach is suitable for studying monohydrated inorganic acids with different hydrogen atom orientations. We carried out MP2 calculations with aug-cc-pVDZ basis set for both monohydrated acids. MP2 results serve as a benchmark for DFT calculations.

• 대한소아치과학회지
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• 제26권1호
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• pp.1-13
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• 1999

To study the caries patterns in primary dentition, 719 preschool children, 4-6 years old, were examined for their caries activity(salivary reductase activity) and caries experience of individual teeth. Teeth groups were made by cluster analysis using dft indexes of individual teeth as criteria. The six major teeth groups in the order of dft index from high to low were (1) lower primary molars, (2) upper primary molars, (3) upper central incisor, (4) upper lateral incisor, (5) canines, and (6) lower incisors. There were significant differences in dft index between teeth groups except upper lateral incisor and canines. Upper and lower primary molars showed the highest correlation in dft index, and the next couples were upper central incisors and upper lateral incisors, upper lateral incisor and canines, upper central incisor and canines, upper lateral incisor and upper primary molars, and canines and upper primary molars in descending order. Upper first primary molar showed the greatest differences in dft index between caries activity levels.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.288-290
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• 1999

In view of the importance of DFT(Discrete Fourier Transform) in spectrum analysis, its computation efficiency is a topic. This paper presents calculation time to extract the power frequency at a fault signal using DFT. Furthermore, it is tested a relaying algorithm based on modified DFT and its application to Micro-controller.

• 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.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4560-4570
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• 2022

Dynamic fault tree (DFT) and its related research methods have received extensive attention in safety analysis and reliability engineering. DFT can perform reliability modelling for systems with sequential correlation, resource sharing, and cold and hot spare parts. A technical modelling method of DFT is proposed for modelling ship collision accidents and loss-of-coolant accidents (LOCAs). Qualitative and quantitative analyses of DFT were carried out using the cutting sequence (CS)/extended cutting sequence (ECS) method. The results show nine types of dynamic fault failure modes in ship collision accidents, describing the fault propagation process of a dynamic system and reflect the dynamic changes of the entire accident system. The probability of a ship collision accident is 2.378 × 10^-9 by using CS. This failure mode cannot be expressed by a combination of basic events within the same event frame after an LOCA occurs in a marine nuclear reactor because the system contains warm spare parts. Therefore, the probability of losing reactor control was calculated as 8.125 × 10^-6 using the ECS. Compared with CS, ECS is more efficient considering expression and processing capabilities, and has a significant advantage considering cost.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.136-136
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• 2013

High-resolution photoemission spectroscopy (HRPES) measurements were collected and density functional theory (DFT) calculations were conducted to track the coverage dependent variation of the absorption structure of 2-thiophenecarboxaldehyde (C4H3SCHO: TPCA) on the Ge(100) surface at room temperature. In an effort to identify the most probably adsorption structures on the Ge(100) surface, we deposited TPCA molecules at a low coverage and at a high coverage and compared the differences between the electronic features measured using HRPES. The HRPES data provided three possible adsorption structures of TPCA on the Ge(100) surfaces, and DFT calculations were used to determine the plausibility of the structures. HRPES analysis, corroborated by DFT calculations, indicated that an S-dative bonded structure was the most probable adsorption structure at relatively lower coverage levels, the [4+2] cycloaddition structure was the second most probable structure, and the [2+2]-C=O cycloaddition structure was the last probable structure on the Ge(100) surfaces at relatively higher coverage levels.