• 전자공학회논문지B
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• 제32B권6호
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• pp.932-942
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• 1995

A spacecraft power system can be divided into two types : DET system(Direct Energy Transfer system) and PPT system(Peak Power Tracking system). In a DET system employing the regulated bus voltage control method, the battery charger and discharger are widely used for the bus voltage regulation. The battery charger has two different modes of operation. One is the bus voltage regulation mode and the other is the charge current regulation mode. The battery discharger is employed to provide the power when the spacecraft is in the earth's shadow or the sun is eclipsed. The operating mode, charging or discharging, is selected by a power control circuit. In this paper, small-signal dynamic characteristics of battery charging and discharging system are analyzed to facilitate design of control loop for optimum performance. Control loop designs in various operating modes are discussed. Anaylses are verified through experiments.

• Journal of Power Electronics
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• 제16권5호
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• pp.1821-1832
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• 2016

This study presents a strategy using the synchronized output regulation method (SOR) for controlling inverters operating in stand-alone and grid-connected modes. From the view point of networked dynamic systems, SOR involves nodes with outputs that are synchronized but also display a desirable wave shape. Under the SOR strategy, the inverter and grid are treated as two nodes that comprise a simple network. These two nodes work independently under the stand-alone mode. An intermediate mode, here is named the synchronization mode, is emphasized because the transition from the stand-alone mode to the grid-connected mode can be dealt as a standard SOR problem. In the grid-connected mode, the inverter operates in an independent way, in which the voltage reference changes for generalized synchronization where its output current satisfies the required power injection. Such a relatively independent design leads to a seamless transfer between operation modes. The closed-loop system is analyzed in the state space on the basis of the output regulation theory, which improves the robustness of the design. Simulations and experiments are performed to verify the proposed control strategy.

• 한국통신학회논문지
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• 제33권7C호
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• pp.529-533
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• 2008

본 논문은 FTTH 도입에 대비하여 현행 국내 광가입자망 구축 공법 및 케이블 포설 등에 관련된 기술기준의 개정 사항 도출을 위하여 광케이블의 곡률 반경과 밴딩 횟수의 변화에 따른 광케이블 채널 손실 특성 및 이종 모드간 광케이블 접속 시 발생하는 채널 손실 특성을 시험 측정하였다. 곡률 반경 및 밴딩 횟수의 변화에 따른 시험 측정 결과 30mm의 현행 허용 곡률 반경 기준을 보다 완화하여도 채널 손실 기준을 만족하는 것으로 나타났으며, 이종 모드간 케이블 접속 시험 측정에서는 다중 모드로부터 단일모드로의 접속 시 원활한 정보 전달이 불가능 한 것으로 나타나 향후 이종 모드간 광케이블 접속 규격에 대한 보다 심도 있는 연구가 요구되고 있다.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.9-14
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• 2002

The durability prediction of emission control components, especially 02 sensor and catalytic converter, is getting more important as emission regulation is getting stricter and vehicle durability mileage requirement is also extended from 80,000 ㎞ to 160,000 km in Korean market. And the duration of vehicle mileage accumulation to get vehicle exhaust emission deterioration factor for certification is required to be shorter in order to reduce the vehicle development time. Since most of the vehicle emission development tests are done on chassis dynamometer and aging bench by using vehicle aging modes, real road condition and in-use driving patterns must be reflected into them to predict the vehicle emission level and to meet emission regulation especially at high mileage. In order to get the frequent driving pattern of vehicle and the aging characteristic of emission components, a vehicle was tested by changing drivers and driving roads around Seoul. Real road driving patterns were analyzed and compared with those of the certification modes which are well known in automotive industry.

• 한국경제지리학회지
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• 제14권4호
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• pp.453-466
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• 2011

이 논문의 목적은 1961년부터 2010년까지 한국의 경제발전 궤적을 고찰하는데 있다. 이 기간 동안 한국 경제의 고성장은 시기별로 다른 한국의 발전모델에 기인한다. 한국의 발전모델을 시기적으로 살펴보면, 1980년대 후반까지의 발전양식은'대량생산-대량수출'과'고생산성-저임금'의 결합을 통하여 구현된 수출지향형 산업화 모델에 초점을 두고 있다. 이후 1990년대 후반까지의 발전모델은'대량생산-대량수출'전략을 지속해 오면서'고생산성-고임금'의 결합에 기초하고 있으며, 2000년 이후의 발전모델은 한국의 금융위기를 극복하기 위하여'공공부문과 민각부문의 재편'및'시장화 전략과 사회 안전망의 점진적 확충'에 초점을 두고 있다. 이와 같은 발전모델은 첫째, 세계적 차원의 조절양식인 무역제도, 환율, 세계와 한국 간 산업관계, 개발도상국에 대한 차관 제도와 관계가 있으며, 둘째, 국가적 차원에서의 조절양식인 국가, 자본, 노동 간에 이루어지는 3각 관계의 변화와 관계가 있다. 그러므로 세계적-국내적 차원에서 조절양식은 한국의 수출지향형 자본축적 과정을 안정화시키는 데 있어서 중요한 게임의 규칙이 된다.

• 한국경제지리학회지
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• 제3권1호
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• pp.53-81
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• 2000

1980년대에서 1997년 사이에 한국 섬유 의류산업은 국내 가격경쟁력을 기반으로 한 수출주도형 성장체제에서 생산력의 지리적 확장을 가져오는 해외생산 그리고 고급의류 내수시장의 증가로 따른 기술 발달과 자동화에 기반을 둔 질적 성장체제로 전환하였다. 이러한 재구조화는 1987년 노동자 대투쟁으로 인한 임금의 급상승으로 1986년까지 진행된 수출주도형 성장체제에 위기가 왔다는데 일차적 원인을 둘수 있다. 특히 임금상승과 노동의 세력화에 따른 단체교섭의 형성은 장시간 노동시간과 저임금 구조에 기반을 둔 대량 생산과 대량수출의 결합체제에 위기를 가져왔다. 따라서 본 논문의 목적은 1980년과 1997년 사이에 발생한 한국 섬유 의류산업의 발전모델 또는 양식의 전환을 밝히고자 하는 것이다. 이를 위해 본 논문은 역사적 맥락에서 1987년 이전과 이후의 축적체제의 변화와 함께 조절양식의 제도적 형태인 임고용 관계, 기업간 관계 그리고 국가와 기업관계의 변화를 살펴보았다.

• Educational Technology International
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• 제20권2호
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• pp.223-255
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• 2019

The purpose of this study is to draw implications for designing online tools to support monitoring in collaborative learning. For this purpose, eighteen research papers that explored learner dashboards and group awareness tools were analyzed. The driving questions for this analysis related to the information and outcomes that must be monitored, whose performance they represent, and who monitors the extent of learning. The analytical frameworks used for this study included the following: three modes of co-regulation in terms of who regulates whose learning (self-regulation in collaborative learning, other regulation, and socially shared regulation) and four categories of dashboard information to determine which information is monitored (information about preparation, participation, interaction, and achievements). As a result, five design implications for learner dashboards that support monitoring were posited: a) Monitoring tools for collaborative learning should support multiple targets: the individual learner, peers, and the entire group; b) When supporting personal monitoring, information about the individual and peers should be displayed simultaneously to allow direct comparison; c) Information on collaborative learning achievements should be provided in terms of the content of knowledge acquired rather than test scores; d) In addition to information related to interaction between learners, the interaction between learners and learning materials can also be provided; and e) Presentation of the same information to individuals or groups should be variable.

• 한국분무공학회지
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• 제23권3호
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• pp.136-148
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• 2018

Major countries have tighten their NOx regulation of diesel passenger cars. In the case of the EU, the regulation has been toughen up to 6.25 times since 2000. Despite the regulation the NOx concentration of the ambient has not been reduced proportionally. As these issues, to reduce NOx emission practically, Korea and the EU introduced the real-world driving emission (RDE) regulation and the test method that will be applied after 2017. In this paper, for the regulation to make a soft landing in Korea, 6 diesel passenger cars which met Euro 6a~6d regulation and were equipped with LNT/SCR were tested at a chassis dynamometer with environmental chamber applying the off-cycles (FTP, US06, SC03, HWFET and CADC) and several ambient conditions (-7 and $14^{\circ}C$) as well as certification modes (NEDC, WLTC@ $23^{\circ}C$). The result of the test showed that the ambient temp. and the engine load as a test mode impacted the NOx emission of the cars while the vehicles with SCR emitted NOx lower than with LNT. Additionally, to propose an effective RDE test method, the above result was compared with the results of the other papers which tested RDE using the same cars.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
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• pp.165-168
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• 2001

Regulation of pyrimidine nucleotide synthesis has been studied extensively in enteric bacteria and Bacillus species. Varieties of control modes have been proposed for regulation of pyrimidine nucleotide biosynthetic (pyr) genes. In Bacillus caldolyticus and B. subtilis, it has been proved that pyrimidine de novo biosynthetic operon is controlled by a regulatory protein PyrR-mediated attenuation. Another Gram-positive bacteria including Enterococcus faecalis, Lactobacillus plantarum, and wctococcus lactis have been found to constitute a pyr gene cluster containing the pyrR gene. In addition, it has been proposed that the structure of the 5' leader region of the Gram-negative extreme thermophile Thermus strain Z05 pyr operon provides a novel mechanism of PyrR-dependent coupled transcription-translation attenuation. Bacterial genome sequencing projects have identified the PyrR homologues in Haemophilus influenzae, Synechocystis sp., Mycobacterium tuberculosis, Streptococcus pneumoniae, S. pyogenes, and Clostridium acetobutylicum, which are currently investigating for their physiological functions.

• 한국지열·수열에너지학회논문집
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• 제17권3호
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• pp.21-29
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• 2021

In this study, the current regulation of the water source energy, one of the renewable energy, was analyzed, and the improvement plan for the high efficient data center cooling system was suggested. In the improvement plan, the design and construction guidelines of the water source energy system permit to adopt the cooling and heating system with or without heat pump. In addition, it should also include the system operated in the cooling mode only all year-round. The domestic test standards to consider the water source operating conditions should be developed. Especially, it is highly recommended that the test standards to include the system with forced cooling and free cooling modes related with the enhanced data center cooling system adopting the water source energy.