• Nuclear Engineering and Technology
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• 제39권2호
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• pp.129-132
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• 2007

It is generally known that software reliability growth models such as the Jelinski-Moranda model and the Goel-Okumoto's non-homogeneous Poisson process (NHPP) model cannot be applied to safety-critical software due to a lack of software failure data. In this paper, by applying two of the most widely known software reliability growth models to sample software failure data, we demonstrate the possibility of using the software reliability growth models to prove the high reliability of safety-critical software. The high sensitivity of a piece of software's reliability to software failure data, as well as a lack of sufficient software failure data, is also identified as a possible limitation when applying the software reliability growth models to safety-critical software.

• Journal of Electrical Engineering and Technology
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• 제2권3호
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• pp.386-390
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• 2007

At recent times, an essential issue in the replacement of the old analogue I&C to computer-based digital systems in nuclear power plants becomes the quantitative software reliability assessment. Software reliability models have been successfully applied to many industrial applications, but have the unfortunate drawback of requiring data from which one can formulate a model. Software that is developed for safety critical applications is frequently unable to produce such data for at least two reasons. First, the software is frequently one-of-a-kind, and second, it rarely fails. Safety critical software is normally expected to pass every unit test producing precious little failure data. The basic premise of the rare events approach is that well-tested software does not fail under normal routine and input signals, which means that failures must be triggered by unusual input data and computer states. The failure data found under the reasonable testing cases and testing time for these conditions should be considered for the quantitative reliability assessment. We presented the quantitative reliability assessment methodology of safety critical software for rare failure cases in this paper.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2001년도 봄 학술발표논문집 Vol.28 No.1 (A)
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• pp.595-597
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• 2001

오늘날 우리가 사용하고 있는 시스템은 날이 갈수록 규모 면에서 대형화되고, 기능면에서 복잡해지고 있다. 이런 복잡성의 증가로 시스템 에러 발생가능성은 더욱 높아졌다. 특히, safety-critical 시스템의 경우 에러가 발생했을 때 인간과 생태계에 엄청난 영향을 미치기 때문에 더욱 신중한 개발 과정이 필요하다. 따라서 정형기법을 이용한 safety-critical 시스템의 개발방법론이 나오게 되었다. 본 논문에서는 대표적인 safety-critical 시스템인 원자력 발전소 시스템에서 Digital Plant Protection System(DPPS)를 가지고 어떻게 방법론이 적용되는지를 보여준다. Software Cost Reduction(SCR)이라는 정형 명세 도구로 명세를 하였고, SPIN 이라는 정형 검증 도구로 그 특성(property)을 검증하였다.

• 한국항공우주학회지
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• 제38권8호
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• pp.813-822
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• 2010

안전성 요구수준이 서로 다른 비행필수 데이터(Flight Critical Data)와 임무필수 데이터(Mission Critical Data)의 시현을 처리하기 위해 별도의 독립된 계기를 사용하지 않고 Glass Cockpit 설계를 적용하여 데이터를 통합처리하였다. 본 논문에서는 독립적으로 설계 진행되어온 비행조종계통과 임무탑재시스템의 통합설계를 위해 설계변경을 최소화하면서 비행조종계통에서 요구되는 비행필수 데이터처리의 안전성 요구수준을 만족시키는 최적화 설계를 제안하였다. 비행필수 데이터의 시현을 처리하기 위해 KUH 임무탑재시스템의 핵심구성품인 임무컴퓨터(Mission Computer)의 하드웨어 및 소프트웨어 설계변경을 최소화하였다. 임무탑재시스템의 안전성 요구도(Safety Requirement)를 검증하기 위한 시험절차를 개발하여 임무탑재시스템 통합시험장비(SIL)를 이용한 시험 수행 결과 안전성 요구도가 만족됨을 확인하였다.

• 한국멀티미디어학회논문지
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• 제15권1호
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• pp.115-130
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• 2012

오늘날 대다수의 안전필수 시스템들(Safety-Critical Systems)에는 컴퓨터, 전기 및 전자 부품이나 장치들에 소프트웨어를 칩에 내장하거나 제어용 소프트웨어 시스템이 탑재되어 구축되고 있다. 이에 따라, 컴퓨터 소프트웨어를 내장하였거나 탑재한 시스템들의 안전성을 평가하기 위한 여러 가지의 결함 분석 기법들이 제안되어져 오고 있다. 이러한 소프트웨어 결함 분석 기법들은 전통적으로는 하나의 안전필수 시스템을 분석하는데 단지 하나의 방법으로만 분석해 왔으나, 시스템의 종류와 특성이 다양해지면서 그 시스템에 가장 알맞은 결함 분석 기법이 동원되어야 함은 필수적이다. 본 연구에서는, 안전필수 시스템에서 소프트웨어의 크기가 비교적 작고, 안전성과 관련한 시스템 제어 반응 시간이 특별히 민감하지 않는 소프트웨어의 안전성을 평가하는 방법으로 결함트리 분석(FTA)과 소프트웨어 고장 유형 및 영향 분석(FMEA)을 결합한 시스템 결함 분석 방법을 제안하고 유비쿼터스 헬스케어 시스템을 이용하여 사례연구를 수행하고자 한다.

• 중환자간호학회지
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• 제15권2호
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• pp.1-13
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• 2022

Purpose : The study aimed to identify relationship among intensive care unit (ICU) nurses' critical thinking disposition, medication error risk level of high-alert medication, and medication safety competency, as well as the factors affecting medication safety competency. Methods : The participants were 266 ICU nurses of one higher-tier general hospital and one general hospital in Province. The data were collected using structured self-administered questionnaire from August 10 to August 31, 2021. Measurements included the critical thinking disposition questionnaire, nurses's knowledge of high-alert medication questionnaire, the medication safety competency scale. Data were analyzed using hierarchical multiple regressions using SPSS/WIN 28.0. Results : In the multiple regression analysis, the medication safety competence has a statistically significant correlation with the working department, the critical thinking disposition, and medication error risk level of high-alert medication. Conclusion : Based on the results of this study, it is suggested to develop and apply an educational strategy that can strengthen the knowledge and skills of critical thinking disposition and medication error risk level of high-alert medication to improve the ICU nurse's medication safety competency.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.153-155
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• 2006

A major advantage of the area in and around Braunschweig is its concentration of major research institutes and small to large enterprises dealing with different modes of transportation. For many years, aviation has been a particular focus. The research institutes have aircraft and helicopters equipped especially for research projects, as well as other laboratory equipment, allowing simulation and testing of air traffic application both virtually and on real aircraft. In addition, with the Luftfahrtbundesamt (equivalent organization to FAA) and the Bundesstelle $f{\"{u}}r$ Flugunfalluntersuchung (equivalent to NTSB) both located at the Research Airport, it enables direct contact with two key air-traffic safety authorities. The institutes of DLR and the Technical University of Braunschweig are very active in rail transportation applications. Cooperation with the market leader in rail automation - Siemens Rail Automation, also located in Braunschweig - and with other companies in the Braunschweig region means that safety-critical road applications and mobility research is available due to the activities of a number of institutes. Cooperation with Volkswagen (VW) and other companies in the region ensure access to the market leaders' know-how in this sector. Current European activities within framework of the Galileo project offer particularly good opportunities for the Research Airport to leverage its expertise and position itself internationally as a specialist in safety-critical transport applications - the centre is an initiative of Niedersachsen and the Ministry of Economic Affairs, Labour and Transport Location and navigation plays a central role in all modes of transport - air, road and rail. The market is being revolutionized by the increasing integration of GNSS. The realization of the Galileo system will provide additional opportunities for the Research Airport: Galileo as a civil operated system offers service guarantees especially in the area of safety-critical applications in transportation. Notably standards, processes and authorizations related to the certification of safety-critical applications in the areas of air, road and rail transportation are still to be determined. GAUSS, located at the Research Airport Braunschweig, as an European centre of excellence for simulation, testing and certification of safety-critical applications can offer its expertise to validate the services guaranteed by the Galileo concessionaire.

• International Journal of Railway
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• 제5권2호
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• pp.84-88
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• 2012

Derailment due to wheel failure would cause a tremendous social and economical cost in service operation. It is necessary to evaluate quantitatively the safety with respect to high-speed train. Although the safety of railway wheel has been ensured by an regular inspection, all critical defects cannot be detected in inspection cycles and the wheel has been replaced because a defect quickly become critical for safety. Therefore, it is important to calculate quantitatively the fracture limit and remnant life of damaged railway wheel in wheel-rail system. In present paper, the critical crack size of wheel for high-speed train is simulated based on fracture scenario and the safety of wheel is evaluated.

• 정보화연구
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• 제9권4호
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• pp.443-453
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• 2012

다양한 분야의 시스템들은 시스템 오류에 인한 피해의 최소화를 목적으로 안전필수 특성을 가지도록 요구된다. 본 논문에서, 안전필수 시스템으로 많이 연구되는 사이버물리시스템이 그 특성을 가지기위해 고려해야하는 이슈와 주요 요소인 시간을 기반으로 모델 지향 아키텍처에 대하여 논의한다. 메타모델링 접근 방식으로 마감시간, 전환상태와 기준치에 연결하여 시간 기반 아키텍처를 제시하고, 이를 모델지향 아키텍처를 이용하여 설계한다. 메타모델로부터 생성된 안전처리 모델과 함께 오류처리 컴포넌트를 사용하여 사이버 물리 시스템 및 시간기반 도메인에 적용 가능한 안전필수 아키텍처를 제시한다. 그리고 안전필수 시스템 설계 시 기본적 안전처리 상태, 다중적 상태, 복합적 상태를 통하여 세부적인 모델과 그 사례를 나타내었다.

• 중환자간호학회지
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• 제16권3호
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• pp.87-98
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• 2023

Purpose : This descriptive survey investigated the effects of clinical nurses' critical reflection competency, professional pride, and person-centered care practices on patient safety management activities. Methods : The participants were 183 clinical nurses working at a tertiary hospital in South Korea. The questionnaires consisted of the Critical Reflection Competency Scale for Clinical Nurses Professional Pride the Person-Centered Nursing Assessment Tool and Patient Safety Management Activities. The collected data were analyzed using descriptive statistics, t-tests, ANOVA, Tukey's HSD, Pearson's correlation coefficient, and multiple regression using SPSS 29.0. Results : The mean score for patient safety management activities was 4.65±0.34 out of 5. There were significant differences in patient safety management activities according to age (F=3.90, p =.010), education level (t=-2.56, p =.013), total work experience (F=3.87, p =.010), and the number of healthcare accreditation system experiences (F=5.22, p =.006). Patient safety management activities were positively correlated with critical reflection competency (r=.337, p <.001), professional pride (r=.271, p <.001), and person-centered care practices (r=.399, p <.001). The results indicated that person-centered care practices affected patient safety management activities (𝛽=.358, p <.001) with the explanatory power of 22.5%. Conclusion : To improve clinical nurses' patient safety management activities, it is necessary to develop participatory educational programs that can integrate skills and attitudes based on conceptual knowledge of person-centered care. Intervention studies are needed to test the effect of person-centered care on patient safety when applied in clinical practice.