• 한국신뢰성학회지:신뢰성응용연구
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• 제9권3호
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• pp.165-176
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• 2009

The risk management case is an organization's formal arrangement to ensure the safety of its work activity within risk management system. It allows an organization to demonstrate its capability in achieving its safety objectives and in meeting regulatory requirements. This paper presents how the safety assessments are described, prepared and maintained to meet the criteria specified by the upcoming safety regulations. We propose the elements of risk management system that include arrangements for the ongoing identification of hazards, assessment of risks and the implementation of necessary control measures.

• Journal of the Korean Statistical Society
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• 제28권4호
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• pp.399-413
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• 1999

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제22권3호
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• pp.169-181
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• 2011

Objectives: The Child Report of Post-traumatic Symptoms (CROPS) and the Parent Report of Post-traumatic Symptoms (PROPS) are screening measures for post-traumatic symptoms in children. The present study aimed to investigate the reliability and validity of the Korean versions of the CROPS and the PROPS. Methods: The Korean versions of the CROPS and the PROPS were administered to a sample of 304 children aged 6 to 15 years old. The internal reliability, test-retest reliability, factorial validity, predictive validity and concurrent validity were evaluated. Results: The reliability of the CROPS and the PROPS was shown to have excellent internal consistency and test-retest correlation. The single factor structure of the PROPS was good and that of the CROPS was borderline acceptable according to confirmatory factor analysis. Other validity measures such as the predictive validity and concurrent validity were also shown to be satisfactory. Conclusion: This study demonstrated that the Korean versions of the CROPS and the PROPS were reliable measures with satisfactory psychometric qualities. Because it takes less than 5 minutes to fill out the CROPS and the PROPS, respectively they can be quick and easy screening scales for assessing post-traumatic symptoms in Korean children.

• The Journal of the Acoustical Society of Korea
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• 제28권3E호
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• pp.109-117
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• 2009

Identity recognition in real environment with a reliable mode is a key issue in human computer interaction (HCI). In this paper, we present a robust person identification system considering score-based optimal reliability measure of audio-visual modalities. We propose an extension of the modified reliability function by introducing optimizing parameters for both of audio and visual modalities. For degradation of visual signals, we have applied JPEG compression to test images. In addition, for creating mismatch in between enrollment and test session, acoustic Babble noises and artificial illumination have been added to test audio and visual signals, respectively. Local PCA has been used on both modalities to reduce the dimension of feature vector. We have applied a swarm intelligence algorithm, i.e., particle swarm optimization for optimizing the modified convection function's optimizing parameters. The overall person identification experiments are performed using VidTimit DB. Experimental results show that our proposed optimal reliability measures have effectively enhanced the identification accuracy of 7.73% and 8.18% at different illumination direction to visual signal and consequent Babble noises to audio signal, respectively, in comparison with the best classifier system in the fusion system and maintained the modality reliability statistics in terms of its performance; it thus verified the consistency of the proposed extension.

• 대한안전경영과학회지
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• 제13권3호
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• pp.45-53
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• 2011

The research proposes seven elimination rules of redundant gates and blocks in Fault Tree Analysis (FTA) and Reliability Block Diagram (RBD). The computational complexity of cut sets and path sets is NP-hard. In order to reduce the complexity of Minimal Cut Set (MCS) and Minimal Path Set (MPS), the paper classifies generation algorithms. Moreover, the study develops six implementation steps which reflect structural importance (SI) and reliability importance (RI) from Reliability Centered Maintenance (RCM) that a priority of using the functional logic among components is to reduce (improve) the system unavailability (or availability). The proposed steps include efficient generation of state structure function by Rare Event Enumeration (REA). Effective use of importance measures, such as SI and ill measures, is presented based on the number and the size of MCS and MPS which is generated from the reference[5] of this paper. In addition, numerical examples are presented for practitioners to obtain the comprehensive understanding of six steps that is proposed in this research.

• 품질경영학회지
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• 제21권2호
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• pp.131-139
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• 1993

The newly proposed model of the future reliability results in earlier fault-fixes having a greater effect than the fault which make the greatest contribution to the overall failure rate tend to show themselves earlier, and so are fixed earlier. The suggested model allows a variety of reliability measures to be calculated. Predictions of total execution time(debugging time) is to achieve a target reliability. This model could also apply to computer-hardware reliability growth resulting from the elimination of design error and fault.

• ETRI Journal
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• 제5권1호
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• pp.10-16
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• 1983

복잡한 시스템의 신뢰도를 해석하기 위해서는 가용도 (Availability) 및 각종 고장간격 등의parameter를 계산하여야 한다. 따라서 이들 parameter를 정의하고 이의 적용성에 대하여 언급하였으며, Markov process를 적용하여 각종 고장간격을 계산하는 기법을 유도하였다. 본 Markov process에 의한 신뢰도 해석기법은 제반 시스템의 상태확률을 계산하여 각종parameter를 구하게 되므로 다양한 시스템의 상태를 해석할 수 있으며, 시스템의 신뢰도 예측은 물론 정비계획을 수행하는 데에도 광범위하게 응용할 수 있다.

• Journal of Preventive Medicine and Public Health
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• 제54권2호
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• pp.153-159
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• 2021

Objectives: Life course exposure to passive smoke may predict health, but there are few validated measures. We tested the reliability and validity of a retrospective life course passive smoking questionnaire. Methods: Participants from the third follow-up of the Childhood Determinants of Adult Health study (2014-2019, ages 36-49 years) retrospectively reported mother/father/other household member smoking when living at home during childhood, including duration (years) and smoking location (never/sometimes/always inside house). The severity of exposure index (SEI; sum of mother/father/other years smoked multiplied by smoking location), cumulative years of exposure (CYE; sum of mother/father/other years), and total household smokers (THS) were derived. The reliability of retrospective passive smoking reports was examined with intraclass correlation coefficients (ICCs) using household smoking reported 34 years earlier in 1985 by participants when aged 7-15 years. Construct validity was examined by correlating retrospective passive smoking with participants' smoking in adulthood and lung function in childhood and adulthood. Results: Among 2082 participants (mean±standard deviation [SD], 45.0±2.5 years; 55.2% females), THS ranged from 0 to 5 (mean±SD, 0.9±1.0), CYE ranged from 0 to 106 (mean±SD, 10.5±13.9), and SEI ranged from 0 to 318 (mean±SD, 24.4±36.0). Retrospective measures showed moderate agreement with total household smokers reported in childhood (ICC, 0.58 to 0.62). The retrospective measures were weakly but significantly (p<0.05) correlated with participants' smoking (r=0.13 to 0.15) and lung function (r= -0.05 to -0.06). Conclusions: The retrospective passive smoking questionnaire showed reasonable reliability and validity. This measure may be useful for epidemiological studies.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.7-13
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• 2011

RAMS is the procedure to maximize the reliability and availability of systems with managing operation rate, the frequency of failure in the system and repair method. Recently, all system life-cycle focusing on RAMS process has been rapidly developing in the field of railway vehicles, for example, applying th reliability management techniques for procurement and disposal of EMU. In particular, global economic recession require to reasonable measures for the EMU maintenance costs under the circumstances therefore, an alternative solution based on RCM(Reliability Centered Maintenance) which is the optimal maintenance method is interested. In this study, the state of being critical of each component and a primary factors was analyzed to improve VVVF inverter of the line 7 EMU by applying FMECA process. Furthermore, this paper showed the impact of connecting between the main and sub system. Based on these data, critical components according to malfunction ratings were classified by screening measures and improvements for each components was summarized.

• 품질경영학회지
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• 제24권3호
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• pp.1-18
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• 1996

The purpose of this study is to empirically examine the role of supplier relationships as a means of enhancement of quality. The model for this study consists of four groups of concepts - 1) goal of quality, as 2) measures of supplier relationships, supplier assistance and buyer supplier communication, 3) the level of automation and technology, as 4) measures of performance, reliability quality and performance quality. By statistical analysis, the results are as follows. First, the goal of quality positively influences the level of automation, technology, supplier assistance and supplier communication. Second, the level of technology has a positive effect on supplier assistance and supplier communication on the level of automation. Third, the level of automation and technology positively influence the reliability quality. Fourth, supplier assistance and buyer-supplier communication has a positive effect on the reliability and performance quality. These results reveal three paths of supplier relationships in systems for the enhancement of quality.