• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.4
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• pp.591-598
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• 2002

In the ship structural design, the material cost of hull weight and the overall cost of construction processes should be minimized considering safety and reliability. In the past, minimum weight design has been mainly focused on reducing material cost and increasing dead weight reflect the interests of a ship's owner. But, in the past experience, the minimum weight design has been inevitably lead to increasing the construction cost. Therefore, it is necessary that the designer of ship structure should consider both structural weight and construction cost. In this point of view, multi-objective optimization technique is proposed to design the ship structure in this study. According to the proposed algorithm, the results of optimization were compared to the structural design of actual VLCC(Very Large Crude Oil Carrier). Objective functions were weight cost and construction cost of VLCC, and ES(Evolution Strategies), one of the stochastic search methods, was used as an optimization solver. For the scantlings of members and the estimations of objectives, classification rule was adopted for the longitudinal members, and the direct calculation method, GSDM(Generalized Slope Deflection Method), lot the transverse members. To choose the most economical design point among the results of Pareto optimal set, RFR(Required Freight Rate) was evaluated for each Pareto point, and compared to actual ship.

• Journal of the Korean Institute of Gas
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• v.14 no.6
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• pp.15-20
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• 2010

Compressed Natural Gas (CNG) buses have been supplied since the year 2000 in order to resolve severe atmospheric pollution in metropolitan area and contributed on the improvement of urban atmospheric environment. However, it is indispensible to take an adequate measure to guarantee the safety of CNG vehicles because of the possibility of huge fire accident. A receptacle, connecting device between high pressure fuel supply tank and fuel line, plays an important role in CNG supply system. In recent, leakage of CNG from receptacles has been reported. So, the concern about the security and reliability of receptacles has been arisen. Therefore, a lot of efforts to prevent leakage are invested among researchers and the durability of this component should be guaranteed despite repeated operation. This research has performed durability tests of a CNG receptacle regarding the repeated usage, extreme chattering, and continuous full flow test. Although a receptacle used for CNG vehicle satisfies validation requirements in the test results, it has been found that failure in the function of leakage prevention in a receptacle could take place in the case of prolonged exposure to high supply pressure in common quick charging environment on site.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.573-579
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• 1997

During the last 30 years, major organ transplantation has become popular, even in Korea, such as kidney, liver, etc. After the successful clinical cardiac transplantation in Korea, many cases of cardiac transplantation are being performed in some centers. But lung transplantation has a lot of obstacles, especially'donor shortage and decreased tolerability of the lung to ischemia-reperfusion injury. Usually it was considered that the maximum safety margin of ischemic time in lung transplantation was about 4 to 6 hours. So, many investigators have tried to develop better preservation methods and experimental model for evaluation of effectiveness in those various methods. But most of those methods had several drawbacks in clinical and experimental settings. So we developed an easily-controllable, reliable, and inexpensive experimental model of isolated rabbit lung block. Using these model, we evaluated its effectiveness and reliability for the experiment of ischemia-reperfusion injury in lung transplantation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.2
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• pp.13-29
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• 2003

Web-mail system is worthy of note as a next generation e-mail system for its mobility and easiness. But many web-mail system does not have any kind of security mechanism. Even if web-mail system provides security services, its degree of strength is too low. Using these web-mail systems, the e-mail is tabbed, modified or forged by attacker easily. To solve these problems, we design and implement secure web-mail system based on the international e-mail security standard S/MIME in this thesis. This secure web-mail system is composed of server system and client system The server system performs basic mail functions - sending/receiving the mails, storing the mails, and management of user information, etc. And the client system performs cryptographic functions - encryption/decryption of the mails, digital signing and validation, etc. Because client system performs cryptographic functions this secure web-mail system gives its reliability and safety, and provides end-to-end security between mail users. Also, this secure web-mail system increase system efficiency by minimize server load.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.8
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• pp.249-258
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• 2022

Since the advent of Bitcoin, various virtual assets have been actively traded through virtual asset services of virtual asset exchanges. Recently, security accidents have frequently occurred in virtual asset exchanges, so the government is obligated to obtain information security management system (ISMS) certification to strengthen information protection of virtual asset exchanges, and 56 additional specialized items have been established. In this paper, we compared the domain importance of ISMS and CryptoCurrency Security Standard (CCSS) which is a set of requirements for all information systems that make use of cryptocurrencies, and analyzed the results after mapping them to gain insight into the characteristics of each certification system. Improvements for 4 items of High Level were derived by classifying the priorities for improvement items into 3 stages: High, Medium, and Low. These results can provide priority for virtual asset and information system security, support method and systematic decision-making on improvement of certified items, and contribute to vitalization of virtual asset transactions by enhancing the reliability and safety of virtual asset services.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.317-321
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• 2022

In response to Incheon tap water accident in 2019, the Ministry of Environment has created the "Comprehensive Measures for Water Safety Management" to improve water operation management, provide systematic technical support, and respond to accidents. Accordingly, K-water is making a smart water supply management system for the entire process of tap water. In order to advance the response to water accidents, it is essential to secure the reliability of real-time water operation data such as flow rate, pressure, and water level, and to develop and apply a warning algorithm in advance using big data analysis techniques. In this paper, various statistical techniques are applied using water supply operation data (flow, pressure, water level, etc) to prepare the foundation for the selection of the optimal operating range and advancement of the monitoring and alarm system. In addition, the arrival time is analyzed through cross-correlation analysis of changes in raw water turbidity between the water intake and water treatment plants. The purpose of this paper is to study the model that predicts the raw water turbidity of a water treatment plant by applying raw water turbidity data considering the time delay according to the flow rate change.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.202-203
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• 2023

The Ministry of Oceans and Fisheries is providing maritime safety services through the operation of the Korean e-Navigation service, and research is continuously needed to improve reliability and quality to secure the competitiveness of the system. In order to secure such competitiveness, we presented the basic design for the big-data maritime information gateway system for minimizes thereal-time operation impact of the Korean e-Navigation service, and a theoretical hardware structure diagram including pseudonymization procedures to implement the overall system and solve privacy security issues. However, the proposed structure diagram and design include only the overall concept, to link real-time maritime information, required detailed privacy security method to satisfy the Privacy Act of the Republic of Korea. To solve this problem, this study will identify factors to violate the Privacy Act within the real-time maritime information(privacy of shipowner, shipping company, captain, navigator, fisherman, etc.) linked by the big-data maritime information gateway system, and research the method to link the secured information to other institutions by encrypting identified the factors.

• Journal of Agricultural Extension & Community Development
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• v.20 no.4
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• pp.1181-1216
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• 2013

This study was accomplished to enhance brand value for hanwoo and to develop strategy for brand positioning that move customer's heart. This study in order to achieve the research was carried out as follows: First, the cluster analysis based on demographic characteristics for consumer on the basis of three types segmentation on market was conducted. Market A was consisted of a well-educated, high-income and young bracket. Market B was consisted of a well-educated, high-income and middle-aged bracket. Market C was consisted of a low-income and middle-aged class. Second, consumer's positioning map was analyzed based on perceiving data which are products' functional, emotional, and self-expressive benefits about consumer's feeling beef products. This study was analyzed each relative brand advantage and structure of competition on segmented market by conjoining each brands positioning map and feature vectors map. By the result of the analysis, each brand's positioning strategy was devised. As a result of the study, the hoengseong hanwoo is competitive about all kinds of market. We chooses that hoengseong hanwoo's target is A market, because that brand is evaluated as a high-ranked quality by high-class image of luxury price, quality, brand image. For management improvement sake, this brand(the hoengseong hanwoo) is needed to effort for promoting consumer's awareness about safety and reliability.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.611-616
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• 2013

Many researches have been carried out consistently for the green ship owing to its economic increasement, efficiency and convenience. One of them is an electronic controlled marine diesel engine. However, we are suffered from dissemination of above engine, due to its anxiety about safety and reliability. In order to solve these problems in this study, emission characteristics test of main propulsive two-stroke diesel engine, equipped both electronic control and cam drive fuel injection systems, has been performed and evaluated under the various load conditions. From the test results, we have confirmed that exhaust gas emission characteristics of the electronic control system is similar to the cam drive system in eco-mode operation, but NOx in emission mode has been decreased 100ppm or more in full load condition. HC emission from the electronic control system is decreased 10~20ppm at 50% load, and 35~40ppm at 25% load in comparison to cam drive system. In fuel consumption, it is considered that 7g/kWh is decreased than the value of cam drive system at 700bar of injection pressure, which is 200bar higher than cam drive system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3815-3823
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• 2013

The purpose of this study was to closely examine the influence of field-shock experience and post traumatic stress perceived by fire officials upon somatic symptoms and coping methods. A survey was carried out targeting 362 male and female fire officials who are working at fire safety centers where are located in Gangwon-do Province. The collected data were used SPSS 19.0 and AMOS 19.0 for Windows. It carried out frequency analysis, factor analysis for validity and reliability, Cronbach's ${\alpha}$ analysis, descriptive statistics and correlation. For hypothesis verification, an analysis was carried out by using structural equation modeling. All the statistical analyses were set for the significant level in p<.05. The results are as follows. First, the perceived field-shock stress was indicated to have influence upon post traumatic stress. Second, the perceived field-shock stress was indicated to have influence upon somatic symptom. Third, the perceived field-shock stress was indicated to have influence upon a coping method. Fourth, the post traumatic stress was indicated to have influence upon somatic symptom. Fifth, the post traumatic stress was indicated to have influence upon a coping method. Sixthly, the somatic symptom was indicated to have influence upon a method of coping with stress.