• 제어로봇시스템학회논문지
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• 제12권11호
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• pp.1130-1137
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• 2006

Relaxed Static Stability(RSS) concept has been applied to improve aerodynamic performance of modern version supersonic jet fighter aircraft. Therefore, the flight control systems are necessary to stabilizes the unstable aircraft and provides adequate handling qualities. The initial production flight control system are verified by flight test and it's always an elements of danger because of flight-critical nature of control law function and design error due to model base design method. These critical issues impact to flight safety, and it could be lead to a loss of aircraft and pilot's life. Therefore, development of an easily modifiable RFCS(Research Flight Control System) capable of reverting to a PFCS(Primary Flight Control System) of reliable control law must be developed to guarantee the flight safety. This paper addresses the concept of SSWM(Software Switching Mechanism) using the fader logic such as TFS(Transient Free Switch) based on T-50 flight control law. The result of the analysis based on non-real time simulation in-house software using SSWM reveals that the flight control system are switching between two computers without any problem.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1686-1697
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• 2022

As a part of probabilistic risk (or safety) assessment (PRA or PSA) of nuclear power plants (NPPs), the primary role of human reliability analysis (HRA) is to provide credible estimations of the human error probabilities (HEPs) of safety-critical tasks. Accordingly, HRA community has emphasized the accumulation of HRA data to support HRA practitioners for many decades. To this end, it is critical to resolve practical problems including (but not limited to): (1) how to collect HRA data from available information sources, and (2) how to inform HRA practitioners with the collected HRA data. In this regard, the U.S. Nuclear Regulatory Commission (NRC) and Korea Atomic Energy Research Institute (KAERI) independently initiated two large projects to accumulate HRA data by using full-scale simulators (i.e., simulator data). In terms of resolving the first practical problem, the NRC and KAERI developed two dedicated HRA data collection systems, SACADA (Scenario Authoring, Characterization, And Debriefing Application) and HuREX (Human Reliability data EXtraction), respectively. In addition, to inform HRA practitioners, the NRC and KAERI proposed several ideas to extract useful information from simulator data. This paper is the first of two papers to discuss the technical underpinnings of the development of the SACADA and HuREX systems.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2002년도 춘계학술대회
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• pp.15-21
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• 2002

In the future, all kinds condition of industrial safety is a primary need in all advanced countries in which workplace safety is an issue. Furthermore, the increasing complexity of production systems and the rapidity of technological innovation have consolidated the recognition of the strategic value of safety, alongside the traditional competitive factors such as quality, costs, delivery time and flexibility, In this paper, the some critical issues of changes and counter-plan in an adequate safety management were identified by above considerations as follows： needs of systematic identification and analysis of safety factors； requirements to define priorities and budgeting to support the decision-making process; and needs of audit activities and indicators which measure company performance in terms of safety improvements, and so on.

• Nuclear Engineering and Technology
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• 제43권3호
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• pp.217-242
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• 2011

A variety of Generation III/III+ water-cooled reactor designs featuring enhanced safety and improved economics are being proposed by nuclear power industries around the world in efforts to solve the future energy supply shortfall. Thermal-hydraulics is recognized as a key scientific subject in the development of innovative reactor systems. Phase change by boiling and condensation in the reverse process is a highly efficient heat transport mechanism that accommodates large heat fluxes with relatively small driving temperature differences. This mode of heat transfer is encountered in a wide spectrum of nuclear systems,and thus it is necessary to determine the thermal limit of water-cooled nuclear energy conversion in terms of economic and safety. Such applications are being advanced with the introduction of new technologies such as nanotechnology. Here, we investigated newly-introduced nanotechnologies relevant to boiling and condensation in general engineering applications. We also evaluated the potential linkage between such new advancements and nuclear applications in terms of advanced nuclear thermal-hydraulics.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.623-629
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• 2005

A technical road map is one of critical research methods which include mid/long term strategies and objectives. There are many of projects conducted using this road map. A technical tree is used at the step of planning of the projects. This research was aimed at reviewing previous systems for conducting researches for and a basis required for improving railway safety in the future by finding out inconsistency arising from physical WBS, which is methodology of defining in existing railway technical trees. In the process of this research, we considered differences between systems safety and prevention as well as natures of them using the established technical tree, and set up plans for improving technical tree to secure railway safety as an integrated system.

• 대한인간공학회지
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• 제27권2호
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• pp.15-24
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• 2008

As users increasingly recognize the importance of safety and the Product Liability comes into effect, a company should take responsibility of protecting the users who use its product. In order to produce a safe product and satisfy the needs of users, it is critical for develope opriately and understand the characteristics of the product accurately. Furthermore, a safe product can be realized by considering a safety level of the product in a whole product development process. However, in general, product development projects hardly evaluate the safety of a product in the product planning step. In addition, most of safety evaluation methods which are applied in the product planning step have a tendency to be qualitative because a detailed product design step. Therefore, this research aims at enhancing the performance of the safety evaluation process by applying quantitative methods such as 'AHP' and 'Fuzzy'. AHP can help analysts derive the weight of safety factors. Fuzzy is applied to evaluate the degree of safety of product elements in this paper. The proposed method will be able to improve the safety level of a product by using the quantitative methods in the product planning step.

• 한국철도학회논문집
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• 제10권4호
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• pp.438-443
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• 2007

This paper proposes an integrated SE process for the development of railway systems with safety assessment included. Although the safety assessment process must be performed with SE process properly with good coordination, the interfaces between the two processes have not been clear. Thus, in many of safety critical system developments in Korea, it is difficult to assess safety in proper development phase. The process model proposed in this paper is based on both the concept of system life cycle and the repetitive use of SE process. In each of development phases, appropriate safety assessment methods are described. Also the evaluation of the integrated system incorporating safety factors is described. The resultant process model is expressed by the Enhanced Functional Flow Block Diagram (EFFBD) using a CASE tool. The model also allows timeline analysis for identifying activity flow and data flow, resulting in the effective management of process. In conclusion, the integrated process enable both the SE process and safety assessment process to cooperate with each other from early development phase throughout the whole system life cycle.

• 스마트미디어저널
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• 제12권11호
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• pp.95-102
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• 2023

Road accidents not only caused loss of human lives but also costed 3% of gross domestic product in most of the countries. The road accidents pose significant challenges to public safety and urban transportation management. There is a need to identify the high-risk area of accidents along with the critical day of week and vulnerable time period in order to implement effective preventive measures and optimizing the resource allocation. We collected 5,012 accident data from 대구교통종합정보. This study identified the high-risk locations, days of week, and time periods for accidents in Daegu and estimated the conditional probabilities of accidents occurring based on combinations of location, day of the week, and time period. The result is visualized in the form of dashboard in Tableau. This study holds substantial practical significance for urban planners, transportation authorities, and policymakers in Daegu to strategically allocate resources for traffic management, law enforcement, and targeted safety campaigns.

• 한국정보과학회논문지:소프트웨어및응용
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• 제27권2호
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• pp.120-133
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• 2000

산업현장에서 복합 실시간 계통(HRTS: Hybrid Real-Time Systems) 개발을 위한 정형기법 사용의 주된 장벽은 인지적 어려움이며 이는 또 다른 위험을 초래할 수 있다. 이러한 문제를 극복하기 위해 HRTS 요구분석과 안전성 분석 시 사용자의 인지적 부담을 줄여줄 수 있는 정성적 요구분석 체계를 제안한다. 이 체계는 요구사항 명세를 위한 정성적 정형기법(QFM: Qualitative Formal Method)과 인과정보에 의한 요구사항 안전성 분석기법(CRSA: Causal Requirements Safety Analysis)으로 구성되어 있다. QFM에서는 인공지능 분야에서 연구된 정성추론 이론을 정형명세에 도입하여 요구사항 설계자와 분석자의 인지적 부담을 줄일 수 있도록 하였다. CRSA는 QFM에서 도출한 HRTS 동작의 인과 정보에 따라 체계적으로 위험 원인을 추적할 수 있도록 하여, 기존 결함 트리 분석(FTA: Fault Tree Analysis) 기법의 단점인 분석자의 주관에 의존하는 문제를 해결한다. 월성 원자력 발전소 자동정지계통(Shutdown System 2) 소프트웨어 요구사항 명세와 안전성 분석에 QFM과 CRSA를 적용하여 그 실효성을 입증하고자 하였다.

• 지질공학
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• 제24권4호
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• pp.609-613
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• 2014

The Korean Peninsula, located at the southeastern tip of the Eurasian Plate, is known to be tectonically stable, and no critical evidence has yet been found that would override the safety design of nuclear facilities in South Korea. Because a nuclear power plant, like other major social overhead capital facilities, could cause great damage to both the environment and society through an unexpected tectonic event, even one of extremely low probability, like the Fukushima accident, a defense-in-depth safety approach is required in geological and geotechnical site safety evaluation for nuclear projects. This paper introduces the regulatory procedures that are in place to confirm nuclear site safety and site monitoring (e.g., earthquakes and groundwater) systems applied to nuclear facilities in order to reduce inherent uncertainties within the site safety review of geological and seismological issues related with a NPP project.