• Nuclear Engineering and Technology
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• v.39 no.2
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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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• v.2 no.3
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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.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.8
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• pp.813-822
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• 2010

Integrated data processing for display of flight critical data and mission critical data was conducted without additional display instruments using glass cockpit design. Based on a pre-designed flight critical system and a mission critical system, this paper shows an optimal design of subsystem integration. The design satisfies safety requirements of flight control systems(FCS) and requires minimized modification of pre-designed systems. By conducting integration test using System Integration laboratory(SIL), it is confirmed that the introduced design approach meets the safety requirements of the MEP system.

• Journal of Korea Multimedia Society
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• v.15 no.1
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• pp.115-130
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• 2012

These days, most of safety-critical systems, which are systems those failures or malfunction may result in death or serious injury to people, or loss or severe damage to social systems, or environmental harm, are being built of embedded software or loaded controlling software systems on computers, electrical and electronic components or devices. There are a lot kind of fault analysis methods to evaluate safety of the safety-critical systems equipped computers, electrical and electronic components or devices with software. However, the only assessment method to evaluate software safety of a safety-critical system is not enough to analysis properly on account of the various types and characteristic of software systems by progress of information technology. Therefore, this paper proposes the integrated evaluation method and carries out a case study for the software safety of safety-critical system which embedded or loaded software sizes are small and control response times are not sensitive by use of two security analysis methods which are Fault Tree Analysis (FTA) and Fault Modes and Effect Analysis (FMEA) for ubiquitous healthcare system.

• Journal of Korean Critical Care Nursing
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• v.15 no.2
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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.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.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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• v.5 no.2
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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.

• Journal of Information Technology and Architecture
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• v.9 no.4
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• pp.443-453
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• 2012

In order to minimize the damage from system failures, systems over various fields are requested to contain the safety-critical features. In this paper, we deliver the considerable issues, especially, in the cyber physical systems that is recently used as a safety-critical system, as well as we propose the model driven architecture based on time as its the important factor. Based on meta-modeling approach, we introduce the time-based architecture which is associated with deadline, transition state, and threshold, and also we work out a design for this by using model driven architecture. We propose a realizable safety-critical architecture by means of showing failure handling components with safety transaction model from the meta-model. In the detailed models and the example, we design a basic safety processing state, a multiple safety processing state, and a compound safety processing state for completing the safety-critical system architecture.

• Journal of Korean Critical Care Nursing
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• v.16 no.3
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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.