• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.137-147
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• 2008

A reliability analysis has been performed to investigate the systematic stability of multi-failure modes of rubble-mound breakwaters. The reliability functions of four different failure modes are established straightforwardly. AFDA(Approximate Full Distribution Approcah) reliability models for each failure modes are directly developed and satisfactorily calibrated through the comparison with CIAD's results. In the reliability analysis of single failure mode, the probabilities of failure are calculated and the influence coefficients of random variables in the failure modes are properly evaluated. Meanwhile, three different models such as uni-modal bounds, bimodal bounds, and PNET are applied to evaluate the probabilities of failure of multi-failure modes for rubble-mound breakwaters. It may be found that uni-modal bounds tend to overestimate the probability of failure of multi-failure modes. Therefore, for the systematic reliability analysis of multi-failure modes, it is recommended to use bi-modal bounds or PNET which consider the correlation between the failure modes for rubble-mound breakwaters. By introducing the reliability analysis of multi-failure modes, it could be possible to find out the additional probabilities of failure occurred by the multi-failure modes of a multi-component system such as rubble-mound breakwaters.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1216-1221
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• 2010

An industrial growth needs high quality of productivity and accuracy. So, the needs of power electronics became pressing. Recently both interest and demand about the technique of power electronics systems has been increased. Though power electronics has a lot of strong point, there are several problems which are harmonic effect, EMI(Electromagnetic Interference), malfunction of electric machinery, harmful effect on human, audible noise and so on. Because these problem are a potent influence on motor, so there needs the manufacture and redesign of motor. The real motors of industrial application have designed and manufactured on the basis of confidence. The study on motor using utility power source was verified sufficient to identify confidence of electric machinery on utility power source. However, a study on confidence is in progress about pulse source by switching device. An advanced company are studying to solve this problem. In this research, it is studied that each variables effecting motor reliability have correlation through experiment and more over forecasting the reliability of motor under inverter operation.

• Proceedings of the Korean Association for Survey Research Conference
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• 2002.11a
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• pp.225-240
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• 2002

본 연구의 목적은 인터넷 자료의 신뢰성을 검토한 후 브랜드가치를 평가하는 새로운 접근 방법으로 브랜드파워 지수를 개발함으로써 인터넷으로부터 수집된 자료의 활용 방안을 검토해 보는 것이다. 브랜드파워 지수의 개발에 필요한 자료로 인터넷 사이트의 브랜드주가 자료와 인터넷조사 자료를 이용하였다. 브랜드주가 자료와 실증시의 주가 자료와의 상관관계를 검토하여 자료의 신뢰성을 확인하고 인터넷조사의 결과를 결합하여 상대적 개념의 브랜드파워 지수를 산출하여 브랜드 가치를 평가해 보았다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.2
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• pp.107-113
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• 2011

To evaluate the performance of the hydrodynamic model, we introduced 10 skill assessments that are assorted by two groups: quantitative skill assessments (Absolute Average Error or AAE, Root Mean Squared Error or RMSE, Relative Absolute Average Error or RAAE, Percentage Model Error or PME) and qualitative skill assessments (Correlation Coefficient or CC, Reliability Index or RI, Index of Agreement or IA, Modeling Efficiency or MEF, Cost Function or CF, Coefficient of Residual Mass or CRM). These skill assessments were applied and calculated to evaluate the hydrodynamic modeling at one of Florida estuaries for water level, current, and salinity as comparing measured and simulated values. We found that AAE, RMSE, RAAE, CC, IA, MEF, CF, and CRM are suitable for the error assessment of water level and current, and AAE, RMSE, RAAE, PME, CC, RI, IA, CF, and CRM are good at the salinity error assessment. Quantitative and qualitative skill assessments showed the similar trend in terms of the classification for good and bad performance of model. Furthermore, this paper suggested the criteria of the "good" model performance for water level, current, and salinity. The criteria are RAAE < 10%, CC > 0.95, IA > 0.98, MEF > 0.93, CF < 0.21 for water level, RAAE < 20%, CC > 0.7, IA > 0.8, MEF > 0.5, CF < 0.5 for current, and RAAE < 10%, PME < 10%, CC > 0.9, RI < 1.15, CF < 0.1 for salinity.

• The KIPS Transactions:PartD
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• v.8D no.4
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• pp.387-392
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• 2001

This Many software projects collect grouped failure data (failures in some failure interval or in variable time interval) rather than individual failure times or failure count data during the testing or operational phase. This paper presents the neural network (NN) modeling for grouped failure data that is able to predict cumulative failures in the variable future time. The two variant models of cascade-correlation learning (CasCor) algorithm are presented. Suggested models are compared with other well-known NN models and statistical software reliability growth models (SRGMs). Experimental results show that the suggested models show better predictability.

• Korean Journal of Health Psychology
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• v.14 no.3
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• pp.511-529
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• 2009

The purpose of this study was to develop and validate Korean Game Addiction Scale for children and adolescents. Data from a representative sample of 3,115 children and adolescents residing in Korea were analyzed to identify the factor structure and reliability of the scale. In addition, criterion-related evidence of validity (concurrent and convergent) was examined. Consistent with our theoretical assumptions, the Korean Game Addiction Scale revealed a stable higher order factor structure (second order-one factor, first order-seven factors), and the reliability of the scale was high (average Cronbach's alpha = .84, six week test-retest reliability = .75). The scale was also showed high levels of concurrent and convergent validity. Implications of the findings and directions for future research on game addiction are discussed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.24-28
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• 2014

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.644-654
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• 2016

In this study, we tested the reliability and validity of the Korean Version of nonattachment scale(K-NAS) that Sahdra et al., had developed to measure for nonattachment. In result, the internal consistency coefficient(Cronbach's alpha) of the K-NAS was (.94) high, correlation coefficients of item-total were to .32 from .69. The result of factor analysis showed that single factor accounted for 37.77 % of the total variance. Confirmatory factor analysis and additional exploratory factor analysis demonstrated that the 1 factor model was satisfactory. K-NAS was positively related to experiences scale, self-compassion, psychological well-being and mindfulness, and negatively related to depression. These findings suggest that the Korean Version of Nonattachment Scale(K-NAS) was reliable and valid scale to measure for nonattachment. Finally, The implication of this study and direction for future study were discussed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.1
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• pp.55-63
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• 2019

In engineering problems, many random variables have correlation, and the correlation of input random variables has a great influence on reliability analysis results of the mechanical systems. However, correlated variables are often treated as independent variables or modeled by specific parametric joint distributions due to difficulty in modeling joint distributions. Especially, when there are insufficient correlated data, it becomes more difficult to correctly model the joint distribution. In this study, multivariate kernel density estimation with bounded data is proposed to estimate various types of joint distributions with highly nonlinearity. Since it combines given data with bounded data, which are generated from confidence intervals of uniform distribution parameters for given data, it is less sensitive to data quality and number of data. Thus, it yields conservative statistical modeling and reliability analysis results, and its performance is verified through statistical simulation and engineering examples.

• Journal of the Korean GEO-environmental Society
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• v.25 no.7
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• pp.29-34
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• 2024

Frost heave is one of the significant engineering characteristics of frozen ground and causes severe damages on geo-structures. Although thermo-hydro coupled analyses have been developed to predict frost heave behavior, these analyses involve excessive input parameters and have primarily been validated for frost heave in clayey soils. Frost heave mainly occurs in silty soils, which have relatively higher permeability compared to clayey soils, necessitating careful attention. This study introduces empirical models and verifies their reliability for silty soils. By using the validated model, the correlation of key input parameters is derived, which is expected to enhance the applicability of thermal-mechanical analysis for geo-structures on frozen ground in the future.