• 대한전기학회논문지
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• 제41권2호
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• pp.144-155
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• 1992

A design of a highly stable current-controlled power supply combining the phase-controlled rectifier (PCR), passive filter and active filter is investigated. A digital phase-looked voltage control (PLVC) with a capability of compensating the thyristor firing angles under unvalanced power source is proposed` otherwise the PCR output voltage has low-order subharmonics whose suppression requires a bulky passive filter. The digital PLVC has a fast dynamic characteristics as an inner control loop of the PCR. To suppress further the output ripple, an active filter using a transformer is introduced and its design is described through the frequency domain analysis. An optimal integral, proportional and measurable variable feedback (IPM) controller is designed using the time-weighted performance index based on the time domain analysis. The design method based on the time-weighted performance index gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives good dynamic and static performances.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.565-568
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• 1998

In this paper, we propose a new method for multispectral image compression that is based on highly correlated relational properly taken from a spatial image and its wavelet transform. The highly active regions, such as edges or contour, in the spatial domain are appeared as significant coefficients in the wavelet transform domain; and the low active regions like background as insignificant. These characteristics play an important role in designing the system. The simulation results have shown us that the proposed method has better performance in terms of the reconstructed image quality and the transmitted bit rakes. Practically, our system can be successfully applied to the application areas that require of progressive transmission. For some multispectral images with relatively low activity, we have obtained the more good results.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.381-385
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• 1999

Taq DNA polymerase from Thermus aquaticus has been shown to be very useful in a polymerase chain reaction. Taq DNA polymerase has a domain at the amino terminus (residues 1 to 290) that has 5'-3' exonuclease activity and a domain at the C-terminus that catalyzes the polymerase reaction. Taq DNA polymerase is classified into the Pol I family, which is represented by E. coli DNA polymerase I. The alignment of amino acid sequences for the 5'-3' exonuclease domains of the Pol I family DNA polymerases shows ten highly conserved carboxylic amino acids. Crystallographic studies suggested that six of the carboxylic amino acids are clustered within a 7 $\AA$ radius by chelating three metal ions in the active site. Those six carboxylic residues are mutagenized to alanines in order to better understand their function. All six carboxylic residues, Asp l8, Glu1l7, Asp1l9, Asp120, Asp142, and Aspl44, are crucial for catalysis of 5'-3' exonuclease.

• BMB Reports
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• 제51권12호
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• pp.609-610
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• 2018

Glycosylation is one form of protein modification and plays a key role in protein stability, function, signaling regulation and even cancer. NleB and SseK are bacterial effector proteins and possess glycosyltransferase activity, even though they have different substrate preferences. NleB/SseKs transfer the GlcNAc sugar to an arginine residue of host proteins, leading to reduced $NF-{\kappa}B-dependent$ responses. By combining X-ray crystallography, NMR, molecular dynamics, enzyme kinetic assays and in vivo experiments, we demonstrated that a conserved HEN (His-Glu-Asn) motif in the active site plays a key role in enzyme catalysis and virulence. The lid-domain regulates the opening and closing of the active site and the HLH domain determines the substrate specificity. Our findings provide evidence for the enzymatic mechanism by which arginine can be glycosylated by SseK/NleB enzymes.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2023년도 제35회 한글 및 한국어 정보처리 학술대회
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• pp.425-431
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• 2023

음성 어시스턴트 시스템에서 발화의 의도를 분류하고 새로운 의도를 탐지하는 것은 매우 중요한 작업이다. 끊임없이 인입되는 새로운 발화로 인해 기존에 학습된 모델의 의도 분류 성능은 시간이 지남에 따라 점차 낮아진다. 기존 연구들에서 새로운 의도 발견을 위해 제안되었던 클러스터링 방법은 최적의 클러스터 수 결정과 명명에 어려움이 있다. 이러한 제한 사항을 보완하기 위해, 본 연구에서는 대규모 언어 모델 기반의 효과적인 의도 발견 방법을 제안한다. 이 방법은 기존 의도 분류기로 판단하기 어려운 발화에 새로운 의도 레이블을 할당하는 방법이다. 새롭게 인입되는 OOD(Out-of-Domain) 발화 내에서 오분류를 찾아 기존에 정의된 의도를 탐지하고, 새로운 의도를 발견하는 효율적인 프롬프팅 방법도 분석한다. 이를 액티브 러닝 전략과 결합할 경우, 분류 가능한 의도의 개수를 지속 증가시면서도 모델의 성능 하락을 방지할 수 있고, 동시에 새로운 의도 발견을 자동화 할 수 있다.

• 생명과학회지
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• 제28권4호
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• pp.408-414
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• 2018

Actein은 널리 알려진 승마 추출물의 주요 생리 활성 효능 성분이다. 본 연구에서는 acetylcholine 수용체의 활성을 억제하는 것으로 활용된 AchBP 단백질 길항제(antagonist) tubocurarine과 승마 추출물의 효능 성분 actein 및 actein 유도체(27-deoxyactin, (26S)-actein, (26R)-actein)들의 AchBP 단백질 B와 C domain 활성 부위에 대한 친화도 분석 실험을 컴퓨터 분자결합 분석 방법을 통해 비교하였다. AchBP 단백질 B와 C domain의 3차원 구조정보는 PDB database (PDB ID: 2XYT)를 활용하였다. In silico 결합 분석을 수행하기 위해 PyRx, Autodock Vina, Discovery Studio Version 4.5, and NX-QuickPharm 프로그램을 각 분석 조건에 따라 활용하였다. AchBP 단백질 B와 C domain 활성 부위에 대한 actein의 최대 결합친화도는 -10.50 kcal/mol으로 나왔으며 이는 -9.80 kcal/mol으로 분석된 tubocurarine의 결합 친화도 보다 훨씬 더 높고 효율적인 것으로 분석되었다. Tubocurarine에 비하여 결합친화도 값이 높게 분석된actein, 27-deoxyactein, (26R)-actein 유도체 성분들과 상호작용 하는 AchBP 단백질 활성 부위의 아미노산들 가운데 tryptophan 84와 tyrosine 147이 높은 결합친화도를 형성하는데 매우 중요한 역할을 하는 아미노산으로 예상이 되었다. Tubocurarine의 AchBP 단백질 활성 부위에 대한 X,Y,Z Grid 값은 X=38.300689, Y=112.053467, Z=51.991022으로 나왔으나 actein과 actein 유도체들은 대부분 X=26.4, Y=127.3, Z=43.7 값 주변에 centroid grid를 형성하였다. 즉, tubocurarine이 결합하는 부위와는 다른 부위에 결합하여 AchBP의 활성에 영향을 주는 것으로 사료되었다. 이상의 연구 결과들을 분석해 볼 때, 아세틸콜린 수용체 길항제 tubocurarine보다 승마 추출물 생리 활성 물질인 actein과 그 유도체들이 보다 더 효율적인 아세틸콜린 수용체 길항제로 작용할 수 있음을 확인하였다. 결론적으로 승마 추출물 또는 actein 성분은 피부 주름 개선 효능을 지닌 보톡스를 대체하거나 또는 주름 개선용 화장품 신물질 연구 개발 분야에 효율적으로 활용할 수 있을 것으로 사료된다.

• 대한의용생체공학회:의공학회지
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• 제14권2호
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• pp.125-136
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• 1993

The study of Cochlear biomechanics is to clearly define three biomechanical principles of the Cochlea : Activity, Nonlinearity and Feedback. In this article, the Cochlea is linearly and actively modelled in one dimensional time domain. The sharp tunning of the Basilar Membrane displacement is shown when the amplifying activity of hair cells is added to the model. The amplified energy of the travelling displacement wave is emitted throughout the Cochlear fluid, so that the model becomes unstable. A new technique is introduced to reduce strong echos fro the Helicotrema. It makes the model less unstable. Both pure and click tones are used as input stimuli onto the ear durm. When the model is normal, the click response of the model shows that the backward emission of the amplified fluid pressure has mainly the echos from the Helicotrema. However, when the linear and active model is assumed to be abnormal, that is, some of hair cells are damaged not to produce the active process, the effect of the hair cell damage is resulted in the Oto-acoustic emission. The frequency response of the abnormally emitted sound pressure shows that the Oto-acoustic emission has the information about the characteristic frequency of the damaged hair cell. The main aim of this paper is to demonstrate the active biomechanics of the Chchlea in the time domain.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.1104-1107
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• 2020

The N-terminal domain of the Pseudomonas sp. FB15 phytase increases low-temperature activity and catalytic efficiency. In this study, the 3D structure of the N-terminal domain was predicted and substitutions for the amino acid residues of the region assumed to be the active site were made. The activity of mutants, in which alanine (A) was substituted for the original residue, was investigated at various temperatures and pH values. Significant differences in enzymatic activity were observed only in mutant E263A, suggesting that the amino acid residue at position 263 of the N-terminal domain is important in enzyme activity.

• Asian Journal of Innovation and Policy
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• 제7권1호
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• pp.150-177
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• 2018

We review two specific risk management strategies of venture capitalists (VCs): deal syndication and domain specialization with respect to their explicit role in adjudging and managing the overall magnitude of information asymmetry risks. These are analyzed for three distinct categories of VC firms as classified by their funding stage focus (early vs. late), ownership type (foreign vs. domestic) and the human capital composition of the core VC team (entrepreneurial vs. investor). The analysis is based on both secondary data and primary data for active 72 VC firms in India. Syndication is moderately important for entrepreneurial VC firms, but not at all important for early-stage focused and foreign VC firms. This finding is distinctly different from what has been conventionally observed in the literature. Among the various arenas of domain specialization, high-technology focus is important for all segments of VC firms. In the context of investment-stage focus, foreign VC firms exhibit growth-stage specialization, while entrepreneurial VC firms concentrate on earlier investment stages.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2001년도 10주년 기념 국제학술 심포지움 및 추계학술대회
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• pp.45-45
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• 2001