• Fire Science and Engineering
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• v.17 no.4
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• pp.76-85
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• 2003

In this study, we write down the definitions, their causes and the techniques of analysis as a theoretical consideration of common cause failures, and investigate the limitation and the importance of the common cause failures by applying to the analysis on the fire protection as a representative safety facility. As you can know in the reliability analysis, most impressive cause is the malfunctions of pumping operations; especially the common cause failure of two pumps is dominant. In other words, it is possible to assess system-reliability as twice as actual without CCF From these, CCF is extraordinarily important and the results are highly dependent on the CCF factor. And although it would increase with multiple installations, the reliability are not defined as linear with those multiplications. In addition, the differences in results due to the models for analysis are not significant, whereas the various sources of data produce highly different results. Therefore, we conclude that the reliabilities are dependent on the quality of the usable data much better than the variety of models. As a result, the basic and engineering device for the preventions of CCF of the multiple facilities is to design it as reliably as to design the fire-water pump. That is to say, we must assess those reliabilities using PFD whether they are appropriate to SIL (Safety Integrity Level) which is required for the reliability in SIS (Safety Instrumented System). The result of the analysis on the reliability of the fire-water supply with CCF shows that PFD is 3.80E-3, so that it cannot be said to be designed as safely as in the level of SIL5. However, without CCF, PFD is 1.82E-3 which means that they are designed as unsafely as before.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.153-165
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• 2014

Carbon dioxide capture and storage (CCS) technology is recognizing one of method responding the climate change with reduction of carbon dioxide in atmosphere. In Korea, due to its geological characteristics, sub-seabed geological $CO_2$ storage is regarded as more practical approach than on-land storage under the goal of its deployment. However, concerns on potential $CO_2$ leakage and relevant acidification issue in the marine environment can be an important subject in recently increasing sub-seabed geological $CO_2$ storage sites. In the present study effect data from literatures were collected in order to conduct an effect assessment of elevated $CO_2$ levels in marine environments using a species sensitivity distribution (SSD) various marine organisms such as microbe, crustacean, echinoderm, mollusc and fish. Results from literatures using domestic species were compared to those from foreign literatures to evaluate the reliability of the effect levels of each biological group and end-point. Ecological effect guidelines through estimating level of pH variation (${\delta}pH$) to adversely affect 5 and 50% of tested organisms, HC5 and HC50, were determined using SSD of marine organisms exposed to the $CO_2$-induced acidification. Estimated HC5 as ${\delta}pH$ of 0.137 can be used as only interim quality guideline possibly with adequate assessment factor. In the future, the current interim guideline as HC5 of ${\delta}pH$ in this study will look forward to compensate with supplement of ecotoxicological data reflecting various trophic levels and indigenous species.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.1
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• pp.15-29
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• 2009

Most breakwater armor blocks are designed by using Hudson's or van der Meer's formula. The minimum weight of armor blocks is calculated by equating the resistance to the load in each formula. The larger value is then chosen as the design weight. In this study, we have performed reliability analyses for thus designed breakwater armor blocks of 12 trade harbors and 8 coastal harbors in Korea. The probability of failure calculated by the reliability analysis provides a criterion for evaluating the stability of armor blocks. The calculated probability of failure was almost same for all the breakwaters so that we were able to quantitatively evaluate the safety level of armor blocks of existing breakwaters. We also found that the safety factor used in the deterministic design method and the probability of failure in the reliability design method show a linear relationship. Therefore the probability of failure of existing breakwaters can be quantitatively calculated from the safety factors. The calculated probability of failure could also be used for determining the target probability of failure in the future.

• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.15-29
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• 2016

Research background: Despite the visible growth in radiation usage and nuclear power development, the analysis of their relationship with fundamental rights, a subject of public concern regarding issues including the right to health, environmental rights, safety rights, the right to know, the right to development, and the right to life, is currently non-existent. Methods: By examining various fundamental rights in the context of positive laws regarding radiation and nuclear power in an idealistic perspective that guarantees the maximum degree of rights, this paper aims to propose legislative supplements that will lead to improvements in quality of life. Result and discussion: In the South Korean Constitution, radiation and nuclear power is a subject incorporating several rights, including at least 12 clauses that are directly related to fundamental rights; these constitutional rights are manifested in the various clauses of the 14 positive laws regarding radiation and nuclear power. The question on the relative importance of each fundamental right as reflected in these positive laws- whether the right to life should be prioritized or considered equal in weight to the right to health, environmental rights, the right to know, and safety rights- requires careful deliberation and is difficult to humanly resolve in the short term. Conclusion: Making policy that expands the usage of radiation and nuclear power while simultaneously preventing their associated risks is an important task for the Republic of Korea, and a proper value judgment is necessary to find a balance in its associated rights.

• The KIPS Transactions:PartC
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• v.18C no.5
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• pp.331-338
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• 2011

The RFID system includes a section of wireless communication between the readers and the tags. Because of its vulnerability in terms of security, this part is always targeted by attackers and causes various security problems including the leakage of secret and the invasion of privacy. In response to these problems, various protocols have been proposed, but because many of them have been hardly implementable they have been limited to theoretical description and theorem proving without the accurate verification of their safety. Thus, this study tested whether the protocol proposed by Kenji et al. satisfies security requirements, and identified its vulnerabilities such as the exposure of IDs and messages. In addition, we proposed an improved RFID security protocol that reduced the number of public keys and random numbers. As one of its main characteristics, the proposed protocol was designed to avoid unnecessary calculations and to remove vulnerabilities in terms of security. In order to develop and verify a safe protocol, we tested the protocol using Casper and FDR(Failure Divergence Refinements) and confirmed that the proposed protocol is safe in terms of security. Furthermore, the academic contributions of this study are summarized as follows. First, this study tested the safety of a security protocol through model checking, going beyond theorem proving. Second, this study suggested a more effective method for protocol development through verification using FDR.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.195-201
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• 2018

The government and the police are trying to expand the safety of the people by spreading "four major social evil erasures" intensively crackdown and prevention activities of sexual assault, school violence, domestic violence, and bad foods for the main purpose of security activities I made an effort. However, in spite of such efforts, the public's feelings of social unrest and the concern about security have not been significantly improved. Therefore, in this paper, using R which is the tool for analyzing big data which is most widely used in each field such as enterprise, consulting, public field, etc., R Using variables measured at each level, we analyzed by analyzing multiple regression analyzes, and confirmed what kind of correlation there is in relation to the direction affecting policy improvement I will try to present it.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.103-103
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• 2011

오늘날 우리 사회는 물산업의 성장성을 높이 평가, 국내 물산업 육성이 경제발전을 위하여 중요하다고 말한다. 따라서 정부는 정부대로, 기업은 기업대로 시장의 육성 및 선점을 위하여 많은 노력을 경주하고 있다. 특히 최근에는 국내 물시장의 성장 한계성을 이유로 해외 물시장 진출의 중요성이 강조되고 있다. 하지만 우리사회는 정작 해외 시장 진출을 위해 무엇보다 중요한 부문인 시장에 대한 정보 탐색에는 노력이 미흡한 실정이다. 즉 해외 물시장 진출의 중요성을 강조하고는 있지만, 어느 시장을 목표시장으로 선정해야 하는지, 무엇이 우리의 강점인지, 무엇을 고객에게 줄 것인지 등에 대한 탐색이 미흡함에 따라, 해외 물시장 진출에 대한 속 시원한 해법을 제시하는 이는 많지 않다. 이에 본 논고는 물시장의 성장 가능성이 높을 것이라고 알려진 아시아 시장의 여러 국가 가운데 국내 시장에도 잘 알려져 있지 않은 말레이시아 시장을 중심으로 정부 정책, 시장 환경, 현지 기술력 등에 관하여 살펴보고, 이를 기초로 시장으로서의 기회와 위험, 그리고 국내 기업의 강점과 약점을 살펴보았다. 분석결과로서 기회와 위험, 강점과 약점을 약술하면 다음과 같다. 먼저 기회의 관점에서 말레이시아는 치수사업, 수도사업, 환경정화사업 등 물산업 인프라가 여전히 취약한 점에서 국내 물기업에게 시장으로서의 기회를 제공하고 있다. 둘째, 외국계 기업에 대한 정부의 규제, 부실한 수도 재정 및 낮은 요금 등은 외국계 기업에 게 있어 위험 요인이 된다. 셋째, 높은 기술력을 이용하여 성공적으로 물 인프라를 구축 운영함으로써 선진국 수준의 물안정성 및 안전성을 확보하고, 4대강살리기 사업과 같은 대규모 프로젝트를 통해 녹색성장 모델을 구축함은 국내 물기업의 큰 강점이다. 넷째, 국내 기업에 대한 현지 시장의 낮은 인지도는 약점 요인이 된다. 현지 이해 관계자의 말에 따르면 "한국계 기업은 보유하고 있는 기술력에 비해 '기업' 및 '보유기술'에 대한 홍보가 부족하다"라고 지적한다. 결과적으로 국내 물기업이 현지 시장에 성공적으로 진출하기 위해서는 무엇보다 국내 기업에 대한 그리고 국내 기술력에 대한 적극적인 홍보가 필요할 것이다.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.7-11
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• 2008

기상청은 2008년 현재 전국에 107개의 디지털 지진관측망을 운영하고 있다. 또한 지진관측 유관기관인 한국지질자원연구원, 한국원자력안전기술원, 한전전력연구원에서 각 기관의 목적에 맞게 지진관측소를 운영하고 있으며, 이들 지진관측자료의 공유를 목적으로 실시간으로 통합하는 통합지진과측망(KISS)을 2000년에 구축하여 지진분석에 쓰이고 있다. 한반도의 지진발생 현황은 1978년부터 2007년까지 776회로 약 26회/년 정도가 발생하였다. 최근 중국의 쓰촨성과 일본 이와테 지진으로 지진 및 지진예지에 대한 국민적 관심이 대두되고 있다. 한반도에서도 큰 규모의 지진이 발생할 가능성에 대비해 기상청에서는 지진관측망과 지진예지 목적의 지구물리관측망을 구축 중에 있다. 지구물리관측망은 INTERMAGNET에서 등록할 수 있는 수준의 관측소를 목표로 인위적인 자기장의 교란이 적은 지질학적인 요소들을 고려한 후보지 선정을 위하여 지구자기업무에 관한 기획연구(서만철 2007)를 수행 하였다. 그 결과 국가 중심 지구자기관측소의 위치는 충남 공주시와 청양군 사이에 있는 칠갑산 지역이 가장 좋은 후보지라고 제안하여 청양지역을 주변으로 국유림 및 군유지를 조사하여 충남 청양군 장평면 화산리 산 36-2번지에 후보지를 선정하여 최적의 입지 조건을 검증하기 위해 인천교육대학교의 이휘순 교수 MT탐사를 수행 주변의 배경잡음을 측정하여 양호한 조건을 갖춘 것으로 확인되었다. 지구자기관측소에는 Fluxgate Magnetometer 1대, Total field Magnetometer 1대, Theodolite 1대, SP(Self Potential) Monitoring system 1대와 장비들을 보호 할 수 있는 관측소가 설치될 예정이다

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.12
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• pp.953-960
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• 2020

This paper presents an optimization of gear web design used in a main gear train of an engine reduction gearbox for a rotorcraft. The optimization involves the minimization of a total weight, transmission error, misalignment, and face load distribution factor. In particular, three design variables such as a gear web thickness, location of rim-web connection, and location of shaft-web connection were set as design parameters. In the optimization process, web, rim and shaft of gears were converted from the 3D CAD geometry model to the finite element model, and then provided as input to the gear simulation program, MASTA. Lastly, NSGA-II optimization method was used to find the best combination of design parameters. As a result of the optimization, the total weight, transmission error, misalignment, face load distribution factor were all reduced, and the maximum stress was also shown to be a safe level, confirming that the overall gear performance was improved.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.363-371
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• 2009

The purpose of this study is to verify the safety issue of the tinted vehicle based on the field study as well as the issue of the capacity reduction from the tinted vehicle. Through this study, an innovative experimental method to verify the issues was developed using RTK GPS receivers, and a data collection was conducted using the developed experimental method. Using the collected data, the effects of the ahead vehicle with the windows tinted on the traffic condition such as headways and acceleration noise were analyzed to test that the ahead vehicle with windows tinted too darkly affects the increasing vehicle maneuver as following the degree of tinting. This study was conducted as a frontier study and more studies, for example, full scale analyses considering various road and vehicle conditions need to be conducted in the future.