• Journal of the Korean Geotechnical Society
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• v.36 no.1
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• pp.29-38
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• 2020

These days the circular cross section cofferdam has been frequently used for the earth retaining structures or cut off wall such as ventilating opening, intake tower in cofferdam, shaft for emergency. By the arching effect, the circular cross section type cofferdam has more advantage than a polygon cofferdam in terms of the structural forces and moment. This paper shows the proper approach to analyze the circular cross section cofferdam using 2D Finite Element Method (FEM) for the circular stiffener (ring beam) evaluation. Besides, the various shapes of cofferdam indluding circular cross section have modeled the 3D Finite Element Mothod (FEM). The circular cross section cofferdam shows the minimum reaction force compared with the other shapes of cofferdam.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1156-1162
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• 2014

To prevent the Sewol incident again, by which the victims are 294 dead and still 10 missing, this study analyzed the change of safety consciousness of passengers onboard ship comparatively before and after the Sewol incident. The survey had performed 2 times at Jeju coastal cruise terminal at February 2014 and May 2014, and effective respondents were 394 and 401, respectively. After the Sewol incidents, the answers' ratio that they would follow the routes that the crews show and they would follow the crews' evacuation guides are decreased 24.5% and 18.5%, respectively. This means that the reliability on the crew members were decreased. Although 77.6% passengers responded that they felt nervousness onboard ship, 60% did not take safety lesson(s) and 45% did not know how to wear a life jacket. And also over 50% did not check the evacuation route map and the location of lifeboat, respectively. Meanwhile, 86.9% respondents answered the system of safey lesson should be changed, which has normally done by TV set.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.277-282
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• 2020

The construction of medium-and large-sized microgrid systems by unit area, which is being promoted worldwide, is being developed and expanded in the form of efficient operation of electric grids and independent operation in preparation for power emergencies. Therefore, for the development of the domestic electricity industry, it is urgent to analyze the current status and technology of relevant international standardization, and to make international standardization of domestic standard (draft) on the matters that need to be enacted and newly established. Campus microgrid implements smart grid element technologies such as Integrated Energy Management System(EMS), Distributed Power(DG), Energy Storage System(ESS), Demand Response(DR), and Electric Vehicle(EV) in a university campus. As a system that reduces energy use and improves energy use efficiency and energy independence, standardization is established to secure interoperability and reliability of such systems.

• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.225-233
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• 2011

In this paper, we propose a remote control station based on the awareness of various combat field situation in order for operating multiple unmanned ground vehicles. Our remote control station is capable of sending a variety of messages designed for carrying out the skillful movement for collaborate among unmanned ground vehicles, gathering the information related with combat field situation, and completing the assigned missions which are described by operator in advance. To verify the effectiveness of our proposal, we develop the sophisticated remote control station and conduct a great many remote operating tests for multiple unmanned ground vehicles.

• Journal of the Korean Institute of Gas
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• v.20 no.2
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• pp.49-57
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• 2016

Aqueous ammonia is widely used in household cleaners, fertilizers and denitrification process. It is usually treated in concentrations from 10 % to 30 %, and release accidents have occurred frequently. In this study, we developed a simplified estimating method and equation to calculate threat zone easily in case of emergency due to release accident of aqueous ammonia. We calculated the consequence distance for toxic endpoints of aqueous ammonia(concentration 10 % ~ 30 %) at different puddle areas($1m^2{\sim}500m^2$) using the ALOHA program. Based on the result, we analyzed the relationship between concentration and puddle area with the threat zone and created the equation.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.542-543
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• 2008

전력산업의 환경변화에 따라 단일 공급자였던 한전을 비롯하여 전력판매사업자, 민간부하사업자, 에너지컨설팅사업자 등 에너지관련 서비스를 제공하는 주체자(이하 ESP : Energy Service Provider)의 참여로 전력시장이 경쟁체제로의 변화가 예상된다. 이러한 주체는 전력에너지 관리 최적화를 위한 수요측의 전력자원과 정보의 통합관리가 필요하다. 또한 수요측 서비스 개선과 동시에 수익을 창출할 수 있는 부가 서비스의 개발이 또한 요구될 것이다. 최근 석유가격의 지속적인 상승으로 도매시장가격은 더욱 증가할 것으로 예상된다. 현재 우리나라는 CBP 형태의 전력시장에서 시간대별로 변하는 전력가격(SMP)에 의하여 시장가격이 정해진다. 따라서 시장가격이 높아지면 높아질수록 전력을 구입하고 있는 전력사업자의 경우 구입비의 증가로 재무 건전성 확보에 악영향을 초래한다. 따라서 효율적인 전력 수요절감을 통해 구입전력비를 절감할 수 있는 신수요관리 기법이 필요하다. 이러한 신수요관리 기법은 국가적으로는 하계수급비상 해소와 신규 건설비용 및 혼잡비용을 회피하고, 전력사업자는 구입전력비의 절감을 통해 전력도매시장가격의 안정을 도모할 수 있다. 이러한 수요절감 기법 중 수요측의 자율적인 참여 및 반응을 기반으로 하는 수요반응(Demand Response, 이하 DR)이 있으며, 이는 전력사업자와 수요 측 전력부하설비와의 양방향 통신 및 제어 인프라 구축이 필요하다. 본 논문은 이러한 DR운영에서 반드시 필요한 수요측 전력부하설비와의 양방향 통신 및 제어 인프라구축에 대한 방법 및 결과를 제시하고자 한다.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.220-229
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• 2017

In this paper, To take advantage a variety of DC power as the boost DC-DC converter design specifications through the inductor L and capacitor C through PSPICE to calculate the best estimate of the value. Boost DC-DC converter with a switch device using IRF840 and reverse recovery time Schottky diodes with excellent with constant current controller using D10SC6M and resistance can be configured to considering the Power LED Module was driven by the production. Converter's switching frequency is 50 kHz, the first Duty Rate was made to increase gradually depending on the value of the detection were, 10 % in the output voltage. As a result, the simulated Boost Power LED driver characteristics is in comparison with the design specifications, 5% or less as the error was approximated. Finally, when input 15 V were offered, a stable output 24 V were obtained. and Dimming Control through the adjustment of brightness and current consumption were possible.

• Korean Security Journal
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• no.60
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• pp.227-251
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• 2019

National interest in nuclear safety continues to increase. One of the policies that the government is pursuing is to change a temporary position to a permanent position for irregular special security guards of Nuclear power plants. At this point in time, it is urgent to discuss the method of their physical fitness test because duties of special security guards such as arrest and self-defense, unarmed defensive tactics, proficiency with semiautomatic rifle, etc, demands a lot of physical fitness. The purpose of this study is to analyze the physical fitness tests of police, firefighters and soldiers in Korea, US and Japan through literature review. After that, a new fitness test method suitable for special security guards of nuclear power plants was derived through expert meetings. This study also suggested a guideline to analyze the fitness test results so that the developed fitness method can be introduced to the field. For this purpose, physical fitness tests were conducted on 74 subjects. Based on the results of the experiment, the expected records of special security guard fitness tests were presented.

• Journal of Korea Water Resources Association
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• v.35 no.5
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• pp.597-609
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• 2002

This study suggests a methodology of hydrologic decision making for the establishment of a standard of drought management from the drought analysis by the past drought history and for the drought monitoring and management according to drought processing. The construction and analysis of a decision tree diagram are performed and the step by step plan according to drought severity is suggested. Say, the decision tree diagram is constructed by the transition probability and quantity of monthly precipitation. Then the drought processing is investigated by the analysis of diagram and the 3-step of drought notice, drought warning, and emergency plan are established. The suggested methology in this study can be used for the other area and the decision tree diagram be used by changing the diagram according to the utilization purposes. Also, the choice of monthly PDSI class and precipitation analysis can be performed by the continuous data supplement. And so, a new standard value by the modified diagram is provided and the continuous drought management will be possible.

• Fire Science and Engineering
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• v.22 no.1
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• pp.54-60
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• 2008

The occurrence of fires in heavily populated multiplex buildings is a serious concern. It causes a great threat to many people and a serious social problem. Whenever this kind of fire happens, the authorities are busy preparing partial countermeasures to control the crisis situations. Luckily, the government has enforced a special law regarding safety supervision of majority-used buildings to prepare the basic countermeasures for the buildings' safety. Recently, the multiplex buildings which have multi type compounds have increased in size by getting bigger and bigger. As there are many people who would need to escape and the complicated structures like mazes in buildings of this type, it is not only difficult to prevent a fire but also easy to cause a large loss of lives. For a better fire safety supervision of the buildings, there needs to be passers and owners' good sense of safety, fire proof of the buildings and education of the fire authorities.