• 한국컴퓨터정보학회논문지
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• 제25권4호
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• pp.29-35
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• 2020

본 논문에서는 새로운 구조의 개체명 인식 DeNERT 모델을 제안한다. 최근 자연어처리 분야는 방대한 양의 말뭉치로 사전 학습된 언어 표현 모델을 활용하는 연구가 활발하다. 특히 자연어처리 분야 중 하나인 개체명인식은 대부분 지도학습 방식을 사용하는데, 충분히 많은 양의 학습 데이터 세트와 학습 연산량이 필요하다는 단점이 있다. 강화학습은 초기 데이터 없이 시행착오 경험을 통해 학습하는 방식으로 다른 기계학습 방법론보다 조금 더 사람이 학습하는 과정에 가까운 알고리즘으로 아직 자연어처리 분야에는 많이 적용되지 않은 분야이다. 아타리 게임이나 알파고 등 시뮬레이션 가능한 게임 환경에서 많이 사용된다. BERT는 대량의 말뭉치와 연산량으로 학습된 구글에서 개발한 범용 언어 모델이다. 최근 자연어 처리 연구 분야에서 높은 성능을 보이고 있는 언어 모델이며 많은 자연어처리 하위분야에서도 높은 정확도를 나타낸다. 본 논문에서는 이러한 DQN, BERT 두가지 딥러닝 모델을 이용한 새로운 구조의 개체명 인식 DeNERT 모델을 제안한다. 제안하는 모델은 범용 언어 모델의 장점인 언어 표현력을 기반으로 강화학습 모델의 학습 환경을 만드는 방법으로 학습된다. 이러한 방식으로 학습된 DeNERT 모델은 적은 양의 학습 데이터세트로 더욱 빠른 추론시간과 높은 성능을 갖는 모델이다. 마지막으로 제안하는 모델의 개체명 인식 성능평가를 위해 실험을 통해서 검증한다.

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1137-1140
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• 2008

M1 RNA, the catalytic subunit of Escherichia coli RNase P, is an essential ribozyme that processes the 5' leader sequence of tRNA precursors (ptRNAs). Using KS2003, an E. coli strain generating only low levels of M1 RNA, which showed growth defects, we examined whether M1 RNA is involved in polycistronic mRNA processing or degradation. Microarray analysis of total RNA from KS2003 revealed six polycistronic operon mRNAs (acpP-fabF, cysDNC, flgAMN, lepAB, phoPQ, and puuCBE) showing large differences in expression between the adjacent genes in the same mRNA transcript compared with the KS2001 wild type strain. Model substrates spanning an adjacent pair of genes for each polycistronic mRNA were tested for RNase P cleavage in vitro. Five model RNAs (cysNC, flgMN, lepAB, phoPQ, and puuBE) were cleaved by RNase P holoenzyme but not by M1 RNA alone. However, the cleavages occurred at non-ptRNA-like cleavage sites, with much less efficiency than the cleavage of ptRNA. Since cleavage products generated by RNase P from a polycistronic mRNA can have different in vivo stabilities, our results suggest that RNase P cleavage may lead to differential expression of each cistron.

• 소성∙가공
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• 제18권2호
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• pp.156-159
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• 2009

Slot coating has been wide spread in photo-resist coating on the glass for liquid crystal display. Die in slot coater consists of manifold and land. Material comes in inlet of the die and flow into the manifold and then flow out through the land. The coating thickness variations along the die length depend upon inside of die design such as manifold and die land. However the coating thickness variations along the moving direction(coating direction) of the coater depend upon the operational conditions of coater as well as die lip design. The coating behaviors including atmospheric air have been investigated in this study. Die geometries considered in this study were nozzle gap and length of the die lip. Coating gap and coating speed were the variables fur coating operational conditions. When the nozzle gap and length of die lip increased climbing effect of PR on the downstream die lip was reduced. Subsequently uniformity of coating thickness improved. Uniformity of coating thickness also enhanced as coating gap and coater speed increased. The uniformity of coating gap was related to the velocity vector distributions on the coating surface.

• 대한기계학회논문집B
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• 제26권10호
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• pp.1378-1386
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• 2002

In the present study, velocity profile and wall shear stress distributions of developing turbulent oscillatory flows in an oscillator connected to straight duct located in exit region of a curved duct was investigated experimentally. The experimental study for air flows was conducted to measure axial velocity profiles, shear stress distributions by using the Laser Doppler Velocimetry(LDV) system with the data acquisition and processing system of Rotating Machinery Resolver(R.M.R) and PHASE software. The results obtained from experimental studies are summarized as follows. The critical Reynolds number for a change from transitional oscillatory flow to turbulent flow was about 7500, in the 60region of dimensionless axial position which was considered as a fully developed flow region. The turbulent oscillatory flow, velocity profiles of the inflow period in the entrance region were gradually developed, but those of the outflow period were not changed nearly. Velocity profiles of inflow and outflow were shown as a symmetric form in a fully developed flow region. The wall shear stress distributions of turbulent oscillatory flow increase rapidly as the flow proceeds to downstream and flow was in good agreement with the theoretically.

• Journal of Microbiology and Biotechnology
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• 제23권8호
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• pp.1092-1098
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• 2013

Cassava constitutes an abundant substrate in tropical regions. The production of butanol in ABE fermentation by Clostridium beijerinckii BA101 using cassava flour (CF) was scaled-up to bioreactor level (5 L). Optimized fermentation conditions were applied; that is, $40^{\circ}C$, 60 g/l CF, and enzymatic pretreatment of the substrate. The batch fermentation profile presented an acidogenic phase for the first 24 h and a solventogenic phase afterwards. An average of 37.01 g/l ABE was produced after 83 h, with a productivity of 0.446 g/l/h. Butanol production was 25.71 g/l with a productivity of 0.310 g/l/h, high or similar to analogous batch processes described for other substrates. Solvent separation by different combinations of fractioned and azeotropic distillation and liquid-liquid separation were assessed to evaluate energetic and economic costs in downstream processing. Results suggest that the use of cassava as a substrate in ABE fermentation could be a cost-effective way of producing butanol in tropical regions.

• Journal of Microbiology and Biotechnology
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• 제25권7호
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• pp.963-977
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• 2015

The well-characterized gram-positive bacterium Bacillus subtilis is an outstanding industrial candidate for protein expression owing to its single membrane and high capacity of secretion, simplifying the downstream processing of secretory proteins. During the last few years, there has been continuous progress in the illustration of secretion mechanisms and application of this robust host in various fields of life science, such as enzyme production, feed additives, and food and pharmaceutical industries. Here, we review the developments of Bacillus subtilis as a highly promising expression system illuminating strong chemical- and temperatureinducible and other types of promoters, strategies for ribosome-binding-site utilization, and the novel approach of signal peptide selection. Furthermore, we outline the main steps of the Sec pathway and the relevant elements as well as their interactions. In addition, we introduce the latest discoveries of Tat-related complex structures and functions and the countless applications of this full-folded protein secretion pathway. This review also lists some of the current understandings of ATP-binding cassette transporters. According to the extensive knowledge on the genetic modification strategies and molecular biology of Bacillus subtilis, we propose some suggestions and strategies for improving the yield of intended productions. We expect this to promote striking future developments in the optimization and application of this bacterium.

• 한국토양환경학회지
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• 제2권1호
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• pp.3-12
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• 1997

식물을 이용하여 오염된 토양에 존재하는 유기 및 무기 오염 물질을 제거하는 phytoremediation은 환경 정화를 위한 새로운 기술이다. 독성 중금속, 방사성 핵종 및 독성 유기 오염 물질을 제거하는데 이용될 수 있는 phytoremediation 에는 다음의 세가지 방법이 있다. (1) phytoextraction: 독성 중금속이나 방사성 핵종과 같은 무기 오염 물질을 수화가능한 부분에 축적하는 식물체를 이용하여 정화하는 방법, (2) phytodegradation: 독성 물질을 분해하는 효소를 분비하는 식물체를 이용하거나 효소를 생산해내는 미생물과 밀접한 연관이 있는 식물체를 이용하여 독성 물질을 무독성 물질로 전환하는 방법, 그리고 (3) phytostabilization: 독성 오염 물질을 용존 상태에서 침전 흑은 식물체의 조직이나 주변 토양 matrix에 흡착시켜 안정화시키는 방법이다. 이 기술은 기존의 어떤 처리 방법보다 더 효과적이고 경제적이다.

• 대한토목학회논문집
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• 제7권3호
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• pp.133-139
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• 1987

한강감조구간(漢江感潮區間)에서 과거(過去)에 발생(發生)했던 세 경우(境遇)의 대홍수(大洪水)를 1차원(次元) 유한차분조석(有限差分潮汐)모형을 이용(利用)하여 수치적(數値的)으로 조사(調査)하였다. 홍수추정기법(洪水推定技法)은 인도교(人道橋)의 홍수위곡선(洪水位曲線)으로부터 유량(流量)을 도출(導出), 입력(入力)시키고 또한 하류경우조건(下流境遇條件)으로는 경계단(境界端)의 조위추정치(潮位推定値)를 규정(規定)하므로서 감조구간(感潮區間)의 홍수위(洪水位) 및 유량(流量)을 산정(算定)하는 것이다. 1925년(年), 1972년(年) 및 1984년(年) 대홍수(大洪水)의 초기산정(初期算定) 결과(結果)가 제시(提示)되고 또한 토의(討議)되었다.

• 한국정밀공학회지
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• 제23권4호
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• pp.99-108
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• 2006

Since mold industries are regarded as belonging to three types of bad business, capable young people are reluctant to work in this field. The industries are hard to employ skilled workers who have much experience and knowledge On the mold manufacturing. Thus, effective CAM systems are required for unskilled workers to create process plans and NC data for the manufacturing, and process plans play important roles in the downstream manufacturing processes, such as NC machining, polishing, and final assembly. This study proposes a decision support system that facilitates unskilled workers to easily select high quality NC-data, as well as to increase productivity. The proposed system is assumed to follow a CAM operation scenario that consists of next three steps: 1) identifying several process plans and enumerating feasible unit machining operations (UMOs) from material and part surface information, 2) creating all feasible NC-data based on UMOs using a commercial CAM system, 3) selecting the best NC data among the feasible NC data using four screening criteria, such as machining accuracy, machining allowance, cutting load, and processing time. A case study on the machining of a camera core mold is provided to demonstrate the proposed system.

• 대한기계학회논문집B
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• 제24권6호
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• pp.769-776
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• 2000

Visible spectral characteristics of cross-sectional emissions from a partially premixed methane/air and propane/air flames have been investigated. An optical train with a two-axis scanning mirror system was used to record line-of-sight emission spectra from 354nm to 618nm, and inversion technique was adapted to obtain cross-sectional emission spectra. By analyzing the reconstructed emission spectra, cross-sectional intensities of CH and $C_2$ radicals were separated from the background emissions. The blue flame edge and yellow flame edge were also obtained by image processing technique for edge detection with color photograph of flame. These edges were compared with radial distributions of CH, $C_2$ radicals and background emissions. The CH radicals were observed at blue flame edge. The background emissions were generated by soot precursor at upstream of flame and by soot at downstream of flame. The $C_2$ radicals in propane/air flame were observed more than those in methane/air flame.