• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.12-12
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• 2010

첨단 공정이 필요한 반도체와 LCD, PDP, LED 등의 디스플레이 및 IT 부품을 제조하는데 필요한 장비의 고성능화와 작업환경의 고청정화에 따른 초고진공펌프의 수요 확대와 앞으로 전개될 한-미 FTA에 따른 시장 확대로 인해 크라이오펌프의 국산화가 시급한 실정이다. 고성능 크라이오펌프를 만들기 위해서는 냉각판을 극저온으로 냉각하기 위한 극저온 냉동기 개발도 중요하지만 냉각판(cryoarray)에 최대한 많은 분자를 포획시키는 것 또한 최우선적으로 고려되어야 할 사항 중 하나이다. 이에 본 논문은 크라이오펌프용 냉각판의 분자포획능력에 대하여 연구하였다. 해석에 이용한 냉각판은 현재 상용화된 모델들 중 원형 중앙판에 $45^{\circ}$ 하향 skirt가 달린 형태이며 8장의 냉각판이 일정한 간격을 두고 아래쪽으로 적층되어 있다. 냉각판의 분자포획능력의 해석은 형상계 수법(view factor method)을 이용해 수행하였다. 형상계수법은 크라이오펌프를 n개의 미소면적으로 구성된 밀폐된 공간으로 가정하고 각 미소면적요소의 온도와 흡착계수, 표면조건 그리고 분자유속이 일정하다는 조건을 이용해 분자유속에 관해 n개의 대수연립방정식을 얻고 이 대수연립방정식을 풀어 냉각판의 분자포획능력을 구한다. 해석에 이용한 냉각판의 기체분자포획능력이 구속된 형상에서 얼마나 우수한 가를 알아보기 위해 중앙판의 직경, 입구와 냉각판 사이의 거리, 그리고 각 냉각판 사이의 거리를 변화시켜가며 해석을 수행하고 그 결과를 비교, 분석하였다.

• Journal of the Korea Safety Management & Science
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• v.12 no.2
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• pp.209-216
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• 2010

We need a study of the ratio of successful applicants control methodology about the national technical qualification under the global-green industrial society and rapid change of international circumstances, infinite competition rider society under FTA aspects. It is necessary to develop of HRD Korea selfishness and increase brand value of national technical qualification. So, this study is analysed to the ratio of successful applicants of national technical qualification toward change of the 'bank of problems' control rule, various characters of candidates and the trend of demand and supply of labours instead of the absolute evaluation method. Accordingly, this study suggests to a methodology for the forecasting model of the ratio of successful applicants using the level of problems difficulty and pattern and the candidates academical carriers.

• Journal of the Korean Institute of Gas
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• v.7 no.2 s.19
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• pp.14-21
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• 2003

Frequency analysis of city gas pipeline was studied and then the method to give frequencies of failure by the third-party digging, corrosion, ground movement, and equipment failure which were known to be the major cause of risk of city gas pipeline. The failure by the third-party digging was analyzed by fault tree analysis and the failure by corrosion was analyzed by applying equation calculating remaining strength with time. The failure by ground movement was evaluated by applying modified model which was induced through weighing factors with basic failure rate model. The failure rate of equipment was calculated with both generic and specific data

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.393-404
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• 2005

The environmental problem is a main subject of the 21C and an environment destruction phenomenon by various kinds of environmental materials is reaching serious level. Nations to be classified as the environmental developed country, are born again environmental rich country. And they earn a large income by trade Every kind environmental resource in an international commercial transaction. Especially, the study that a reliability assessment method to prevent to reliability problem to be happened when the solder lead(lead-free solder), non-cd component, non-bromide component(without the polybrominated biphenyls(PBB) and polybrominated diphenyl ethers(PBDE))and hexavalent chromium(Cr VI) clearance component and mercury-free applied to electronic equipment is progressed. As the result of the study for applying of a reliability assessment technique of lead-free solder that recognized the most of urgent problem at the company, combination accelerated life test could taken by adding and appling the part of a humidity acceleration part to Eyring Model which is proposed by R.E.Thomas. The reliability assessment methods study of PWB clean environmental materials is expected to respond to a reliability elevation and environmental material regulation policy spreading all over the world by beginning form Europe.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.3
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• pp.111-116
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• 2021

This study aims to identify the representative factors affecting the air trade between the two countries over the past 20 years, targeting China, Korea's largest trading partner for air transport. In the analysis, the two countries' GDP, GDP per capita, and tariff rates, as well as exchange rates, international oil prices, and FTAs were used as variables. For the analysis method, OLS multiple regression analysis was performed, and each was analyzed by dividing the export amount, import amount, and trade amount. As a result of the analysis, China's GDP and Korea's GDP per capita showed a positive (+) direction, an increase in the exchange rate resulted in an increase in the amount of trade, and an increase in the tariff rate resulted in a decrease in the amount of trade. Whether the FTA was concluded or not acted as a factor in increasing the amount of trade between the two countries.

• Ocean Systems Engineering
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• v.9 no.3
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• pp.261-285
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• 2019

Nowadays in offshore industry there are emerging hazards with vague property such as act of terrorism, act of war, unforeseen natural disasters such as tsunami, etc. Therefore industry professionals such as offshore energy insurers, safety engineers and risk managers in order to determine the failure rates and frequencies for the potential hazards where there is no data available, they need to use an appropriate method to overcome this difficulty. Furthermore in conventional risk based analysis models such as when using a fault tree analysis, hazards with vague properties are normally waived and ignored. In other word in previous situations only a traditional probability based fault tree analysis could be implemented. To overcome this shortcoming fuzzy set theory is applied to fault tree analysis to combine the known and unknown data in which the pre-combined result will be determined under a fuzzy environment. This has been fulfilled by integration of a generic bow-tie based risk analysis model into the risk assessment phase of the Risk Management (RM) cycles as a backbone of the phase. For this reason Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) are used to analyse one of the significant risk factors associated in offshore terminals. This process will eventually help the insurers and risk managers in marine and offshore industries to investigate the potential hazards more in detail if there is vagueness. For this purpose a case study of offshore terminal while coinciding with the nature of the Caspian Sea was decided to be examined.

• Korea Trade Review
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• v.45 no.3
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• pp.55-69
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• 2020

This study examines the research trends and knowledge structure of international trade studies using topic modeling method, which is one of the main methodologies of text mining. We collected and analyzed English abstracts of 1,868 papers of three Korean major journals in the area of international trade from 2003 to 2019. We used the Latent Dirichlet Allocation(LDA), an unsupervised machine learning algorithm to extract the latent topics from the large quantity of research abstracts. 20 topics are identified without any prior human judgement. The topics reveal topographical maps of research in international trade and are representative and meaningful in the sense that most of them correspond to previously established sub-topics in trade studies. Then we conducted a regression analysis on the document-topic distributions generated by LDA to identify hot and cold topics. We discovered 2 hot topics(internationalization capacity and performance of export companies, economic effect of trade) and 2 cold topics(exchange rate and current account, trade finance). Trade studies are characterized as a interdisciplinary study of three agendas(i.e. international economy, International Business, trade practice), and 20 topics identified can be grouped into these 3 agendas. From the estimated results of the study, we find that the Korean government's active pursuit of FTA and consequent necessity of capacity building in Korean export firms lie behind the popularity of topic selection by the Korean researchers in the area of int'l trade.

• Korea Trade Review
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• v.45 no.4
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• pp.65-81
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• 2020

Under New Climate Regime, countries are trying to enhance environmental regulations to meet international standards. This study is designed to examine the relationship between the relative level of environmental regulation of the importing countries and the export performance at the industrial level. Panel data from 2009 to 2018 was established for 12 top export industries and empirical analysis was conducted. For the analysis method, panel OLS, Hausman-Taylor, and panel GLS were used based on the results of the Hausman verification. The dependent variable is the export performance of each industry. As the independent variables, the relative level of environmental regulation, GDP per capita of the importing country, exchange rate, FTA agreement, and physical distance from the importing country were used. Results show that the relative level of environmental regulation has a negative effect on export performance of semiconductors, displays, special machines, general machines, electric appliances, and home appliances. On the other hand, there are no relationship between the relative level of environmental regulation of the importing country and export performance of automobile, petroleum refining, petrochemical, shipbuilding, and communication equipment industries.

• Korean Security Journal
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• no.14
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• pp.43-67
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• 2007

This is the study of efficient security system for candidates for the 17th President. The president election will be held in 20 countries this year. As conflicts between interest groups are expected to emerge, they are afraid of accidental raid in the campaign tour in addition to revival of regionalism and possibility of confrontation between interest groups with issues of anti-FTA In our country. The purpose of this study is to suggest appropriate method through study of security system for president candidate as just 6 months are left for the 17th president election. Also this study covers security environment for the president election, principle of security, and theoretical study for cause of terror, security system domestic and abroad and its analysis and how to provide the efficient security for president candidate. Therefore first, for desirable security the security should be provided by professional org like president security department. Second, combined security for target by current rules should be done. Fourth, total security is necessary to prevent security threats in advance. Third, the public security should be provided for every president candidates. Fifth, example of secret service in America should be studied and economical security should be considered Sixth, we should increase the use of Security Company and martial artists.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.4
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• pp.273-282
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• 2023

Probabilistic safety assessment (PSA) has been widely used to evaluate the seismic risk of nuclear power plants (NPPs). However, studies on seismic PSA for process plants, such as gas plants, oil refineries, and chemical plants, have been scarce. This is because the major disasters to which these process plants are vulnerable include explosions, fires, and release (or dispersion) of toxic chemicals. However, seismic PSA is essential for the plants located in regions with significant earthquake risks. Seismic PSA entails probabilistic seismic hazard analysis (PSHA), event tree analysis (ETA), fault tree analysis (FTA), and fragility analysis for the structures and essential equipment items. Among those analyses, ETA can depict the accident sequence for core damage, which is the worst disaster and top event concerning NPPs. However, there is no general top event with regard to process plants. Therefore, PSA cannot be directly applied to process plants. Moreover, there is a paucity of studies on developing fragility curves for various equipment. This paper introduces PSA for gas plants based on FTA, which is then transformed into Bayesian network, that is, a probabilistic graph model that can aid risk-informed decision-making. Finally, the proposed method is applied to a gas plant, and several decision-making cases are demonstrated.