• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.181-181
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• 2023

Flood is a major threat to human society, and scientific assessment of flood risk in human living areas is an important task. In this study, two different methods were used to evaluate the flood in Ulsan City, and the results were comprehensively compared and analyzed. Based on the fuzzy mathematics and VIKOR method of the multi-objective decision system, similar evaluation results were obtained in the study area. The results show that due to the large number of rivers in Ulsan City and the relatively high exposure index, the whole city faces a high risk of flooding. However, fuzzy mathematics theory pays more attention to the negative impact of floods on people, and the adaptability in the Nam-gu District is lower. In contrast, the VIKOR method pays more attention to the positive role of the economy and population in flood protection, and thus obtains a higher score. Both approaches demonstrate that the city of Ulsan faces a high risk of flooding and that its citizens and policymakers need to invest in preventing flood damage.

• 제어로봇시스템학회논문지
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• 제16권2호
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• pp.188-193
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• 2010

With GPS being the primary navigation system, Loran use is in steep decline. However, according to the final report of vulnerability assessment of the transportation infrastructure relying on the global positioning system prepared by the John A. Volpe National Transportation Systems Center, there are current attempts to enhance and re-popularize Loran as a GPS backup system through the characteristic of the ground based low frequency navigation system. To advance the Loran system such as Loran-C modernization and eLoran development, research is definitely needed in the field of Loran-C receiver signal processing as well as Loran-C signal design and the technology of a receiver. We have developed a set of Matlab tools, which implement a software Loran-C receiver that performs the receiver's position determination through the following procedure. The procedure consists of receiving the Loran-C signal, cycle selection, calculation of the TDOA and range, and receiver's position determination through the Least Square Method. We experiences the effect of an incorrect cycle selection and various error factors (ECD, ASF, sky wave, CRI, etc.) from the result of the Loran-C signal processing. It is apparent that researches which focus on the elimination and mitigation of various error factors need to be investigated on a software Loran-C receiver. These aspects will be explored in further work through the method such as PLL and Kalman filtering.

• Wind and Structures
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• 제19권6호
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• pp.603-621
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• 2014

Past high speed wind events have exposed the vulnerability of the roof systems of existing light-framed wood structures to uplift loading, contributing greatly to economic and human loss. This paper further investigates the behaviour of light-framed wood structures under the uplift loading of a realistic pressure distribution. A three-dimensional finite-element model is first developed to capture the behaviour of a recently completed full-scale experiment. After describing the components used to develop the numerical model, a comparison between the numerical prediction and experimental results in terms of the deflected shape at the roof-to-wall connections is presented to gain confidence in the numerical model. The model is then used to analyze the behaviour of the truss system under realistic and equivalent uniform pressure distributions and to perform an assessment of the use of the tributary area method to calculate the withdrawal force acting on the roof-to-wall connections.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2012년도 한국컴퓨터종합학술대회논문집 Vol.39 No.1(B)
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• pp.21-22
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• 2012

자연재해의 대형화로 인하여 국가적 재난대비의 중요성과 인식이 고취되고 있으며, 미국 및 일본을 비롯한 방재 선진국에서 도입하고 있는 지역사회의 특성을 고려한 재난 대비책의 중요성이 대두되고 있다. 국내에서 각종 재해위험에 대한 각 지역의 방재능력을 여러 가지 방법으로 진단하고 있으나 대부분 지역의 인구, 시설 등의 정량적 정보에 의존하여 평가하고 있어, 지역민과 지역사회 의견 등이 충분히 반영되지 못하는 실정이다. 이를 위해 본 연구에서는 지역사회 대비능력을 포함한 홍수취약성지수를 체계적이고 정량적으로 평가할 수 있는 평가시스템 프로토타입 개발을 제안하였다.

• 품질경영학회지
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• 제19권2호
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• pp.96-107
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• 1991

At the design stage of a plant, the plausible causes and pathways of release of hazardous materials are not clearly known. Thus there exist large amount of uncertainties on the consequences resulting from the operation of a fusion plant. In order to better handle such uncertain circumstances, we utilize the Probabilistic Risk Assessment(PRA) for the safety analyses on fusion power plant. In this paper, we concentrate on the tritium release accident. We develop a simple model that describes the process and flow of tritium, by which we figure out the locations of tritium inventory and their vulnerability. We construct event tree models that lead to various levels of tritium release from abnormal initiating events. Branch parameters on the event tree are assessed from the fault tree analysis. Based on the event tree models we construct influence diagram models which are more useful for the parameter updating and analysis. We briefly discuss the parameter updating scheme, and finally develop the methodology to obtain the predictive distribution of consequences resulting from the operating a fusion power plant. We also discuss the way to utilize the results of testing on sub-systems to reduce the uncertain ties on over all system.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.223-230
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• 1999

The seismic damage assessment to the postulated earthquake is attempted for the buildings in the model district of Seoul City. The capacity spectrum method is employed in which the vulnerability functions are expressed as functions of the spectral displacement. the database of the building stock is constructed and managed using Geographic Information System software. The model district is selected to represent the typical structural and residential characteristics of Seoul City The structural properties were collected from the design documents. The field inspections were carried out to find out the current status of the building. They are classified into 11 structural types. The fragility curves in HazUS are employed, The ground motions from the postulated earthquakes are simulated using the Boor's methods, The surface soil in the district is classified into 3 profiles using the depth as the parameter. The one-dimensional wave propagation method is used to calculate he filtered ground motion through surface soil layer. The average spectrum of this sample time histories is used as the demand curves. The calculated results are expressed in maps using GIS software ArcView 3.0a

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2013년도 추계학술발표대회
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• pp.680-683
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• 2013

방화벽, 백신, IPS, 취약점 점검 시스템 등 중요 시스템의 보안을 위해 다수의 소프트웨어들이 운용되고 있다. 그 중 취약점 점검 시스템은 중요 서버의 보안 취약점을 점검하여 사전에 보안 위협을 예방한다는 측면에서 중요하다. 그러나 서버의 취약점을 점검해주는 소프트웨어 자체에 취약점이 존재한다면 취약점 보완을 위해 도입한 시스템이 취약점을 내포하고 있는 모순된 상황을 발생시킨다. 본 논문에서는 취약점 점검 시스템의 매니저와 에이전트의 점검 패킷을 분석하여 데이터 필드에 임의의 값을 주입하는 SPIKE 기반의 퍼즈 테스팅 기법으로 매니저와 에이전트 모두에서 DoS(Denial of Service) 취약점을 발견하였다. 해당 취약점은 다수의 SQL 세션을 생성하고 시스템의 CPU 점유율을 100%로 높여 시스템의 다른 서비스조차 이용할 수 없는 상태를 보였다.

• 정보보호학회논문지
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• 제26권6호
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• pp.1605-1618
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• 2016

최근 몇 년 동안 금융회사(은행, 증권사, 신용카드사, 보험사 등)를 대상으로 한 개인정보 유출, 홈페이지 해킹, 분산 서비스거부공격(DDoS) 등 보안사고가 꾸준히 증가하고 있다. 본 논문에서는 현행 전자금융기반시설의 정보보호 관리수준의 문제점을 법적 준거성과 정보보호 인증제도 관점에서 분석하고 금융 분야 특성에 적합한 종합적인 관리체계 하에서 높은 수준의 정보보호 활동이 지속 가능하도록 정보보호관리체계, 정보보호 준비도 평가 및 주요정보통신기반시설 취약점 분석 평가 제도를 활용한 개선방안을 제시하고자 한다.

• Journal of Positioning, Navigation, and Timing
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• 제11권1호
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• pp.23-28
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• 2022

The eLoran system is a high-power terrestrial navigation system that is recognized as the most appropriate alternative to complement the GNSS's vulnerability to radio frequency interference. Accordingly, Korea has conducted eLoran technology development projects since 2016. The eLoran system developed in Korea provides 20 m positioning accuracy to maritime user in Incheon and Pyeongtaek harbor. To accurately calculate the position with the eLoran signal, it is necessary to apply a compensation method that mitigates the propagation delay. In this paper, we develop the compensation method to mitigate the eLoran signal propagation delay and evaluate the positioning performance in Incheon harbor. The propagation delay due to the terrain characteristics is pre-surveyed and stored in the user receiver. Real-time fluctuations in propagation delay compared to the pre-stored data are mitigated by the temporal correction generated at a nearby differential Loran station. Finally, two performance evaluation tests were performed to verify the positioning accuracy of the Korean eLoran system. The first test took place in December 2020 and the second in April 2021. As a result, the Korean eLoran service has been confirmed to provide 20 m location accuracy without GPS.

• 환경영향평가
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• 제28권1호
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• pp.1-22
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• 2019

본 연구에서는 국가 생태분야 기후변화 리스크 평가와 연계한 적응 정책 및 연구의 방향성에 대한 시사점을 마련하고자 하였다. 본 논문에서 검토한 적응 정책과 연구에 대한 해외 모범사례의 공통점은 국가 적응정책 수립 시 과학적 근거기반 구축 및 불확실성 저감을 목표로 국가단위에서 기후변화가 생물다양성과 생태계에 미치는 영향 연구를 강조한다는 점이다. 이에 비추어 추후 국가 정책 마련 시 기후변화 협약과 생물다양성 협약 등 효율적 통합적 준수를 위한 적응체계를 유도하고, 적응의 경제적 가치평가를 통한 정책 반영, 과학적 연구 프로그램 강화 및 기술 개발의 측면을 보강하여 보다 성공적인 국가적응 정책 구조를 정착해 갈 수 있어야 할 것이다. 특히 생태계 분야 적응방안이 보다 실효성 있게 실행되기 위해서는 우리나라 서식지 및 종의 기후변화 리스크 요소(위해, 노출, 취약성)에 대한 과학적 진단과 분석을 바탕으로 리스크를 평가하고 이에 대한 적응방안을 통합하여 고민하는 노력이 필요할 것이다.