• Industrial Engineering and Management Systems
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• 제3권1호
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• pp.59-62
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• 2004

The number of tunnel has fast increased with the rapid expansion of highway network. Tunnel should be designed to provide for drivers both safety and pleasant driving conditions. In this perspective, the design for tunnel lightning is very important in order to provide its safety, pleasantness, and cost-efficiency of maintenance, all of which should be considered and analyzed for a better tunnel lighting. This paper attempts to compare the low-pressure sodium lamp, which have usually been used for tunnel lighting, with the fluorescent lamp, which we consider as an alternative for the former. In an effort to determine the number of lamps to meet the required illuminance in the tunnel, this research employs a simulation technique which would allow us to conjecture, with the aid of basic model, the life cycle cost for illumination per each tunnel. This analysis is expected to provide a basic method and related information for tunnel development and design.

• 한국안전학회지
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• 제33권3호
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• pp.8-14
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• 2018

Ni-base superalloy has excellent resistance to extreme environments such as high temperatures and high stresses and are used as materials for large gas turbines. In this paper, the specimens were taken from the blade that were used for a long time, and their life span was studied by microstructure analysis and avoidance of cursing. The microstructural analysis of the specimens was carried out using a OM and SEM to observe the coarsening, carbides on gamma prime. Low-cycle fatigue tests were performed on new material and airfoil of long time-used blade. The test was conducted under various deformation conditions and temperature conditions of $760^{\circ}C$ and $870^{\circ}C$. The low cycle fatigue test was carried out using the Coffin-Manson equation and the fatigue life was predicted. After the test, crack path and fracture surface were analyzed using SEM.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제6권12호
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• pp.543-548
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• 2017

최근에는 의료기기의 구성 요소 중 소프트웨어의 기능과 역할이 커지고, 의료기기 소프트웨어의 작동이 사용자의 생명과 안전에 직결되는 특성으로 인해 의료기기 소프트웨어의 안전성 보장에 대한 중요함은 더욱 강조되고 있다. 이를 위해 의료기기의 안전성을 효과적으로 보장할 수 있는 활동과 각각의 요구사항들을 제시하고 있는 여러 표준이 제정되었다. 표준들이 의료기기 소프트웨어의 안전성을 보장하기 위해 제시하는 활동으로는 크게 의료기기 소프트웨어의 개발생명주기와 위험관리 프로세스로 나뉜다. 이 두 활동은 개발 과정 중 동시에 진행되어야 하지만, 의료기기 소프트웨어 개발생명주기의 각 단계에서 수행되어야하는 위험관리 요구사항들은 분류되어있지 않다는 한계점이 있다. 이로 인해 개발자들은 의료기기 개발 중에 직접 표준들의 연관성을 분석하여 위험관리 활동을 수행해야한다. 따라서 본 논문에서는 의료기기 소프트웨어 개발생명주기와 위험관리 프로세스의 연관성을 분석하고, 위험관리 요구사항 항목들을 추출한다. 그리고 분석한 연관성을 토대로 추출된 위험관리 요구사항 항목을 개발생명주기에 대응시킴으로서, 의료기기 소프트웨어의 개발 중 효과적이고 체계적인 위험관리를 가능하게 한다.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3517-3527
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• 2021

New 80-MW (electric) ultra-long-life sodium cooled fast reactor core having inherent safety characteristics is designed with heterogeneous fuel assemblies comprised of driver and blanket fuel rods. Several options using upper sodium plenum and SSFZ (Special Sodium Flowing Zone) for reducing sodium void reactivity are neutronically analyzed in this core concept in order to improve the inherent safety of the core. The SSFZ allowing the coolant flow from the peripheral fuel assemblies increases the neutron leakage under coolant expansion or voiding. The Monte Carlo calculations were used to design the cores and analyze their physics characteristics with heterogeneous models. The results of the design and analyses show that the final core design option has a small burnup reactivity swing of 618 pcm over ~54 EFPYs cycle length and a very small sodium void worth of ~35pcm at EOC (End of Cycle), which leads to the satisfaction of all the conditions for inherent safety with large margin based on the quasi-static reactivity balance analysis under ATWS (Anticipated Transient Without Scram).

• 한국안전학회지
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• 제23권5호
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• pp.125-130
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• 2008

PSC보의 보강 시에 안전도분석을 위한 신뢰성해석과 생애주기비용을 최소화하기 위만 최적설계를 실시하였다. 신뢰성해석은 현재 공용중인 표준단면을 변형시키면서 실시하며 자연적 불확실성과 인위적 불확실성을 고려하였다. 자연적(내재적) 불확실성을 고려하여 최소생애주기비용을 구한 후에, 인위적 불확실성을 최대 90%의 분산까지 고려하여 재해석을 실시하였다. 보강방법에 대한 신뢰성해석과 최소생애주기비용해석은 보강방법을 결정하는데 매우 합리적인 기준을 제시하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제6권4호
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• pp.189-199
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• 2002

This study is intended to propose a systematic procedure for the development of the conditional assessment based on the safety of structures and the cost effective performance criteria for designing and upgrading of bridge structures. As a result, a set of cost function models for a life cycle cost analysis of bridge structures is proposed and thus the expected total life cycle costs (ETLCC) including initial (design, testing and construction) costs and direct/indirect damage costs considering repair and replacement costs, human losses and property damage costs, road user costs, and indirect regional economic losses costs. Also, the optimum safety indices are presented based on the expected total cost minimization function using only three parameters of the failure cost to the initial cost (${\tau}$), the extent of increased initial cost by improvement of safety (${\nu}$) and the order of an initial cost function (n). Through the enough numerical invetigations, we can positively conclude that the proposed optimum design procedure for bridge structures based on the ETLCC will lead to more rational, economical and safer design.

• 한국전산구조공학회논문집
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• 제26권6호
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• pp.415-421
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• 2013

본 논문에서는 면진시스템이 원전에 적용될 경우 원전구조물의 생애주기 성능에 미치는 영향을 소개한다. 최근 내진설계와 더불어 강진발생 예상 지역에 적용을 목적으로 개발되는 면진시스템은 구조물을 장주기화하여 응답가속도를 줄이고 상대변위를 늘려줌으로써 구조물의 안전성을 증진시키는 것으로 알려져 있다. 따라서, 구조물의 안전성이 중요시되는 원전구조물에 면진시스템을 적용하기 위한 연구가 국내에서 진행 중에 있다. 본 연구에서는 원전구조물의 생애주기 성능분석에 있어서 특징을 분석하고, 면진시스템이 적용될 경우 원전구조물의 생애주기성능에 있어서 미치는 영향을 평가함으로써, 도출된 결과를 면진시스템 적용의 정량적인 타당성 평가에 활용할 수 있다.

• 시스템엔지니어링학술지
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• 제15권2호
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• pp.108-115
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• 2019

The activities of managing and controlling the configuration of a system component over its life cycle are critical tasks in developing a high safety system as well as general system development. These configuration management activities should be defined through the management plan at the beginning of the life cycle, and should be performed continuously and systematically until the end of the project after the system or product development is completed. In this study, the configuration management process applied in the development of high safety railway signaling system was introduced and an efficient application proposals of it was proposed. In particular, configuration management through the establishment of a configuration management system based on computer tools is one of the important activities of maintaining the configuration integrity of the system or product.

• 대한안전경영과학회지
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• 제13권4호
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• pp.9-16
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• 2011

Modern systems become more complex and the demand for systems safety goes up sharply. Thus, the proper handling of the safety requirements in the systems design is getting greatly increased attention these days. Hazard analysis has been one of the active areas of research in connection with systems safety. In this paper, we study a subject on how the hazard analysis results can be incorporated in the systems design. To this end we set up a goal on how to systematically generate safety requirements that should reflect hazard analysis results and be implemented in the systems design and development. To do so, we first review the process for systems design and suggest the associated Model. Then the process and results of hazard analysis are analyzed and Modeled particularly with emphasis on the safety data. The resulting data Model incorporating both the hazard analysis and system life cycle is used in the generation of safety requirements. Based on the developed data Model, the generation of the requirements, the construction of requirements DB, and the change management later on is demonstrated through the use of a computer-aided software tool.

• 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.