• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.208-212
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• 2008

Gas hydrate has been paid attention to study for because: 1) it can be considered as a new energy resources; 2) one of reasons causing the instability of sea floor slope and 3) a factor to the climate change. Bottom simulating reflector (BSR) defined as seismic boundary between the gas hydrate and free gas zone has been considered as the most common evidence in the seismic reflection data for the gas hydrate exploration. BSR has several characteristics such as parallel to the sea bottom, high amplitude, reducing interval velocity between above and below BSR and reversing phase to the sea bottom. Moreover, instantaneous attribute properties such as amplitude envelop, instantaneous frequency, phase and first derivative of amplitude of seismic data from the complex analysis could be used to analyze properties of BSR those would be added to the certain properties of BSR in order to effectively find out the existence of BSR of the gas hydrate stability zone. The output of conventional seismic data processing for gas hydrate data set in Ulleung basin in the East sea of Korea will be used for complex analyses to indicate better BSR in the seismic reflection data. This result of this analysis implies that the BSR of the analyzed seismic profile is clearly located at the two ways time (TWT) of around 3.1 seconds.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.809-812
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• 2008

Structural parameter variation effects (changing the coplanar gap under different discharge dimensions) and use of complex gas mixtures (He, Ne, Ar and Xe) in mercury-free fluorescent lamps are studied in this paper. Pure Neon gas is the best buffer gas for obtaining high luminous efficiency in mercury-free fluorescent lamps. It is shown that with a shorter coplanar gap (30mm), a high luminous efficiency can be obtained at low operating voltage, as well as high luminance uniformity and stable discharge with a Ne-Xe 20% gas mixture.

• 한국추진공학회지
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• 제21권1호
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• pp.91-97
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• 2017

한국형발사체 발사대시스템은 지상기계설비, 추진제공급설비, 발사관제설비 그리고 기반시설로 구성된다. 추진제공급설비의 구성품인 고압가스 공급시스템은 우주발사체 발사 운용에 필요한 고압가스를 저장하고 각 사용처에 공급하는 역할을 수행한다. 고압가스 공급시스템은 고압가스 저장부, 조정패널, 제어서브시스템 등으로 구성되며, 조정패널 중 자동패널은 제어기와 연동되어 원격으로 구동이 가능하도록 구축된다. 본 논문에서는 한국형발사체와 발사대시스템 지상설비의 특성을 고려하여 설계된 고압 가스 공급시스템에 대해 소개하고자 한다.

• 한국위험물학회지
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• 제6권2호
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• pp.77-86
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• 2018

Interest in renewable energy is increasing for eco-friendly use of energy, and fuel cells are being used in various ways such as houses and buildings as power generation methods that have low emissions such as $NO_X$ and $CO_2$. As the supply of fuel cells expands, more and more boilers are installed in the existing buildings, but safety management is not being performed properly. Therefore, in this study, a prior study was conducted on the status of fuel cell-boiler complex installation and related criteria, and the risk factors were analyzed according to the installation environment and structure. Based on these standards, the safety performance of the fuel cell-boiler combined installation is assessed by conducting a demonstration using the starting product of the simulated operation to derive the installation criteria (proposal) for the fuel cell-boiler combined installation. The installation criteria (proposal) include the construction and connection method of the piping according to the fuel cell-boiler complex installation.

• 한국추진공학회지
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• 제23권2호
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• pp.95-103
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• 2019

고압가스공급설비 제어시스템은 발사대 인증시험 및 발사운용에 필요한 고압가스를 저장하고 공급하는 설비를 제어하는 역할을 수행한다. 발사대를 구성하는 대부분의 설비는 운용을 위해 고압가스를 필요로 한다. 그렇기 때문에 고압가스공급설비를 제어하는 제어시스템은 발사대를 구성하는 다른 시스템 보다 먼저 개발과 검증이 이루어져야 한다. 하드웨어와 소프트웨어 검증은 구분하여 수행한다. 특히, 제어기에 탑재되는 제어알고리즘 소프트웨어 검증은 제어시스템 개발 기간 중 많은 시간과 인력 비용이 투입된다. 따라서 구체적인 시험절차와 방법이 사전 준비가 되어야 효율적 개발이 가능하다. 본 논문에서는 고압가스공급설비와 제어시스템 구성을 소개하고 주요 알고리즘 검증 절차 및 그 동작 결과를 제시한다.

• Journal of Magnetics
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• 제18권2호
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• pp.202-206
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• 2013

In this paper, the MFL (magnetic flux leakage) signals of complex defects on the underground gas pipeline are analyzed and their depths are estimated. Since closely-located defects (complex defects) affect each other, accelerate the progress of defection, and are finally combined to one (cluster), it's meaningful to differentiate complex defects from single defects by analyzing their characteristics. Various types of complex defects are characterized and analyzed by defining the safety distance for interference. 26 artificial defects are carved on the pipeline simulation facility (PSF) to analyze the characteristics of complex defect and demonstrate the accuracy of the proposed complex defect estimation. The proposed method shows average length error of 5.8 mm, average width error of 15.55 mm, and average depth error of 8.59%, respectively.

• 천문학회지
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• 제29권spc1호
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• pp.183-186
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• 1996

We report the results of H I 21-cm and molecular line studies of the shocked interstellar gas in the W51 complex. We present convincing evidences suggesting that the shocked gas has been produced by the interaction of the W51C supernova remant (SNR) with a large molecular cloud, Our results show that W51C is the second SNR with direct evidences for the shocked cloud material.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.156-157
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• 2005

Gas hydrate is ice-like crystalline lattice, formed at appropriate temperature and pressure, in which gas molecules are trapped. It is worldwide popular interesting subject as a potential energy. In korea, a seismic survey for gas hydrate have performed over the East sea by the KIGAM since 1997. In this paper, we had conducted numerical and physical modeling experiments for seismic properties on gas hydrate with field data which had been acquired over the East sea in 1998. We used a finite difference seismic method with staggered grid for 2-D elastic wave equation to generate synthetic seismograms from multi-channel surface seismic survey, OBC(Ocean Bottom Cable) and VSP(Vertical Seismic Profiling). We developed the seismic physical modeling system which is simulated in the deep sea conditions and acquired the physical model data to the various source-receiver geometry. We carried out seismic complex analysis with the obtained data. In numerical and physical modeling data, we observed the phase reversal phenomenon of reflection wave at interface between the gas hydrate and free gas. In seismic physical modeling, seismic properties of the modeling material agree with the seismic velocity estimated from the travel time of reflection events. We could easily find out AVO(Amplitude Versus Offset) in the reflection strength profile through seismic complex analysis.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.188-191
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• 2008

There have been many methods for producing natural gas from gas hydrate reservoirs in permafrost and sea floor sediments. It is well knownthat the depressurization should be a best option for Class 1 gas hydrate deposit, which is composed of tow layers: hydrate bearing layer and an underlying free gas. However many of gas hydrate reservoirs in sea floor sediments are classified as Class 2 that is composed of gas hydrate layer and mobile water, and Class 3 that is a single gas hydrate layer. The most appropriate production methods among the present methods such as thermal stimulation, inhibitor injection, and controlled oxidation are still under development with considering the gas hydrate reservoir characteristics. In East Sea of Korea, it is presumed that the thick fractured shale deposits could be Class 2 or 3, which is similar to the gas hydrate discovered offshore India. Therefore it is needed to evaluate the possible production methods for economic production of natural gas from gas hydrate reservoir. Here we would like to present the production of natural gas from gas hydrate deposit in East Sea with industrial flue gases from steel company, refineries, and other sources. The existing industrial complex in Gyeongbuk province is not far from gas hydrate reservoir of East Sea, thus the carbon dioxide in flue gas could be used to replace methane in gas hydrate. This approach is attractive due to the suggestion of natural gas productionby use of industrial flue gas, which contribute to the reduction of carbon dioxide emission in industrial complex. As a feasibility study, we did the NMR experiments to study the replacement reaction of carbon dioxide with methane in gas hydrate cages. The in-situ NMR measurement suggeststhat 42% of methane in hydrate cages have been replaced by carbon dioxide and nitrogen in preliminary test. Further studies are presented to evaluate the replacement ratio of methane hydrate at corresponding flue gas concentration.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.285-288
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• 2006

유전자 알고리즘은 자연선택과 유전법칙을 적용하여 최적해를 탐색하는 방법으로, 본 연구에서 항공기용 가스터빈 엔진의 결함 진단을 위한 학습 알고리즘으로 사용되었다. 성능 저하를 고려한 구성 요소는 압축기, 가스발생기 터빈, 동력 터빈이며, 설계점에서 엔진의 구성 요소에 대하여 복합 결함 진단을 수행하였다. 그 결과, 압축기, 가스발생기터빈, 동력터빈모두 10% 이내의 오차로 예측됨을 확인하였다.