• 한국안전학회지
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• 제26권4호
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• pp.7-13
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• 2011

A study on reliability estimation of sequential-ordered multiple failure modes, which are sequentially ordered between failure modes in a considering system, was performed. Especially, an approach to estimate the probabilities of failure modes has been proposed under an assumption that failure modes are mutually exclusive and sequentially ordered by only a critical variable. A feasibility of the proposed approach were studied by a practical example, which is a reliability estimation of passive safety systems for a probabilistic safety assessment(PSA) of a very high temperature reactor(VHTR) that is under development as a future nuclear system with enhanced safety features. It is difficult to define a robust failure state of this nuclear system because of its enhanced radiation release characteristics, so the new approach is a useful concept to estimate not only its safety but also a PSA. A feasibility study applied two failure modes(e.g., small and large release of radioactive materials) with considering the integrated behavior of this nuclear system. It is expected that the multiple release states for a practical estimation can be easily extended to the aforementioned example. It was found out that the proposed approach was a useful technique to cover the unfavorable features of this nuclear system as to performing a VHTR PSA.

• International Journal of Railway
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• 제8권1호
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• pp.5-9
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• 2015

Reliability based limit state design method is replacing traditional deterministic designs such as allowable stress design and/or ultimate strength design methods in world trends. European design code(Eurocode) has adopted limit state design, and Korea road bridge design standard has also recently been transferred to limit state design method. In this trend, Korea railroad design standard is also preparing for adopting the same design concept. While safety factors are determined empirically in traditional design, load combinations as well as load factors are determined by solving limit state equations. General partial safety factors are evaluated by using AFORM(Advanced First Order Reliability Method) in the reliability based limit state design method. In this study sensitivity analysis is carried out for a dead load factor and a live load factor. Relative precisions of the dead load and the live load factors are discussed prior to the AFORM analysis. Furthermore the sectional forces of design and the material quantities required by two different design methods are compared for a PSC box girder railway bridge.

• 한국기계가공학회지
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• 제20권2호
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• pp.14-22
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• 2021

A plan for the development of reliability-based ROK amphibious assault vehicles is proposed. By analyzing the development case of the U.S. EFV, considerations for the successful development of the next-generation Korea Forces amphibious assault vehicle are presented. If the vehicle reliability can be improved to the level of the fourth highest priority electric unit for power units, suspensions, decelerators, and body groups, which have the highest priority among fault frequency items, a system level MTBF of 36.4%↑ can be achieved, and the operational availability can be increased by 3.5%↑. The next-generation amphibious assault vehicles must fulfill certain operating and performance requirements, the underlying systems must be built, and sequencing of the hybrid engine and the modular concept should be considered. Along with big-data- and machine-learning-based failure prediction, machine maintenance based on augmented reality/virtual reality and remote maintenance should be used to improve the ability to maintain combat readiness and reduce lifecycle costs.

• 유통과학연구
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• 제12권7호
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• pp.103-110
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• 2014

Purpose - This study attempts to examine the new concept of mobile internet users' lifestyles through empirical analyses based on the i-VALS concept study that had classified the VALS program, among others, aiming at internet users. Research design, data, and methodology - A total of 300 questionnaire copies were distributed, of which 273 were collected; only 244 were used for the empirical study after excluding some inappropriate or unusable ones. To analyze the data collected, the SPSS/WIN 19.0 statistical package was used, and the lifestyles of mobile internet users were reclassified after analyzing the reliability and validity of the responses. Results - The study involved the empirical analyses of the new concept of the mobile internet users' lifestyles based on the i-VALS concept study, of which the subjects were internet users. Conclusion - It is possible to provide enterprises with more systematic and objective fundamental data based on the characteristics of mobile internet users' lifestyles, to help enterprises with their establishment of market segmentation strategies for promoting mobile shopping in the future.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.19-24
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• 1999

This paper addresses a new project being carried out at Satellite Technology Research Center. The purpose of the project is to implement a system which receives, processes and stores 1m resolution satellite image transmitted at over 300Mbps down link data rates. In order to develop such a system, a system operational concept design and a requirements study were being carried out As a result of the operational concept design, system objectives, system context and system functions were defined. The system shall be operated according to the philosophy of maximum automation. rapid processing, reliability, integrity, cost effectiveness, and expandability. The system is divided into twelve independent processes and its behavior is modeled by operational scenario, which are combinations of independent processes. Process information and logs generated by the system shall be stored in databases and data received and generated be automatically archived and managed in a hierarchical storage device. The system shall have redundant components in order to be ready for recovering from sudden system failures. This paper will describe in detail the system operational concept design and the system requirements derived from the operational concept design.

• 한국지구과학회지
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• 제24권6호
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• pp.508-523
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• 2003

본 연구에서는 고등학생들의 천문학적 공간개념 수준을 측정하기 위한 검사도구를 개발하였다. 이 검사도구는 천문학적 공간개념을 이루고 있는 기본적인 하위 요소들 (공간위치, 공간추리, 공간변화)을 평가할 수 있는 평가문항으로 구성되어있다. 개발된 검사도구는 274명의 고등학생들에게 투입되어 검증되었다. 문항 분석결과, 본 검사도구의 내용타당도는 98%였으며, 신뢰도(K-R 20)는 0.84, 정답율 52%, 변별도 지수 0.27로 나타났다. 따라서 이러한 결과는 본 검사도구가 고등학생들의 천문학적 공간개념 수준을 측정할 때 활용 가능함을 의미한다.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.987-1000
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• 2021

The concept of 'Employer branding' (EB) - one effective and sustainable strategy to attract and retain talent - has received a lot of attention from researchers and business managers. This concept becomes more meaningful when the 'war of talent' takes place in an extremely fierce manner in Vietnam as well as around the world. However, this concept is rather new; as a result, many points related to 'EB' scales should be improved, especially in Vietnamese context. Therefore, this study focuses on developing and confirming the EB scale in the context of Vietnam. Based on EB theory, this research applies the mixed research method: qualitative methods (expert interview and group discussion) and quantitative method (questionnaire survey of 937 respondents). EB is demonstrated to be a quadratic concept, consisting of the following 10 dimensions: Corporate social responsibility (CSR), Promotion (PRO), Work-Life Balance Satisfaction (WLSA), Education (EDU), Behavior-based Family interference with work (WLBE), Travel opportunities (TRA), Time-based work interference with family (WLTI), Teamwork (GRO), Supporting (SUP), and Strain-based family interference with work (WLST) with 58 observed variables. Based on the survey towards the employees in enterprises and organizations in Vietnam, the analysis results affirm that this scale ensures efficiency, reliability, unidirectionality and convergent values.

• Clinics in Shoulder and Elbow
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• 제16권1호
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• pp.58-62
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• 2013

서론: 최근 임상 연구와 논문의 활성화 속에 높은 신뢰도를 보장하는 방법을 따르는 예들은 아직 많지 않다. 이에 연구의 편향을 최소화하는 무작위 추출의 개념과 바른 방법에 대해 알아보고자 한다. 대상 및 방법: 최근까지 발표된 무작위 추출에 대한 문헌 고찰을 통해 무작위 추출의 기본 개념 및 필요성을 정리하고 바른 무작위 추출을 위한 조건 및 무작위 추출의 종류별 방법들(단순 무작위 추출, 순열화 블록 무작위추출, 계층화)에 대해 살펴 보았다. 결과 및 결론: 무작위 추출은 임상 연구에서 편향을 줄이고 통계적 검사를 이용한 자료 분석의 보장된 유효성을 제공한다. 이렇듯 보다 신뢰도 높은 연구 결과를 도출해 낼 수 있는 방법인 무작위 추출에 대한 개념 재정립 및 바른 무작위 추출 방법의 제안은 연구자들에게 꼭 필요한 과정이라 할 수 있겠다.

• 한국건설관리학회논문집
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• 제13권3호
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• pp.43-55
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• 2012

최근 건설 산업에서 이슈가 되고 있는 BIM의 신뢰성을 판단하기 위한 방안으로 BIM 품질 검증 방안이 대두되고 있다. 그러나 현재 BIM 품질 검증은 부재간의 간섭체크, 공간 배치 등 3D Model을 검토하는 것에 국한되어 있으며, 구조, 설비, 견적과 같은 각 분야별 BIM기반 작업 결과물의 검증 방안은 부재한 실정이다. 특히 BIM기반 견적분야에서는 수량 산출의 근거인 산출식이 출력되지 않아 BIM기반 물량산출 결과물을 신뢰하지 못하는 현상이 발생하였다. BIM기반 견적 작업 결과물의 신뢰성을 향상시키기 위해 제조업에서 정의하고 있는 신뢰성 개념을 분석하고, 다년간 BIM기반 물량산출 수행 경험을 토대로 BIM기반 견적 또는 물량산출 작업의 신뢰성에 영향을 미치는 요인을 도출한 결과, 모델링 방법 및 BIM Tool의 특징에 따라 BIM기반 물량 데이터가 달라지는 것을 알 수 있었다. 따라서 본 연구에서는 BIM 기반 견적 모델링 시 모델링 방법에 따른 결과값의 분석과 IFC 파일 교환을 통해 데이터의 신뢰성을 높이는 올바른 모델링 방법 및 데이터 검증 방안을 제시하고자 한다.

• 한국항공우주학회지
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• 제40권4호
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• pp.364-374
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• 2012

본 연구에서는 발사체의 개념설계 단계 동안 성능 변수뿐만 아니라 신뢰성에 따른 개발비용 추정방안을 분석하고자 하였다. 과거에는 발사체의 개발비용을 예측하기 위해서 주로 발사체의 성능과 건조 질량 등을 독립변수로 하는 추정 방법이 많이 이용되었다. 이러한 접근 방법은 비교적 근사하였지만 신뢰성 수준에 따른 비용 변화를 반영할 수 없기 때문에 원하는 신뢰성을 가진 발사체의 개발비용을 근접하게 예측하기는 쉽지 않았다. 본 논문에서는 이러한 비용추정 방법의 한계를 개선하기 위해 성능과 질량을 기반으로 한 비용 모델인 TRANSCOST에 신뢰성 개념을 도입하여 발사체 비용을 추정할 수 있는 방법론을 제시하였다. 이를 기반으로 신뢰성에 따른 한국형발사체(KSLV- II)의 개발비용을 추정했다.