• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.438-438
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• 2023

최근 전 세계적으로 기후변화가 심해지고 있어 자연재해 또한 늘어나고 있다. 많은 자연재해 중 겨울철 재해인 대설 피해는 2012년부터 2021년까지 10년동안 약 1,200억의 피해액이 발생하였고 많은 재산 피해의 위험이 있어 지속적인 연구가 필요하다. 그 중 충남지역의 피해액은 약 200 억으로 우리나라의 피해액 중 두 번째로 많다. 따라서 본 연구에서는 PSR(Pressure Index, State Index, Response Index)과 DPSIR(Driver force Index, Pressure Index, State Index, Impact Index, Response Index) 방법을 이용하여 충남지역의 대설에 대한 취약성을 분석하여 더 신뢰할 수 있는 대설 위험지역을 제시하였다. PSR 방법은 압력지수, 상태지수, 반응지수로 구분되고, DPSIR 방법은 추진력, 압력, 상태, 영향, 대책 지수로 나뉜다. 각 지표에 해당하는 데이터베이스를 구축하고 엔트로피 방법을 이용하여 가중치를 산정하고 충남지역의 대설 취약성 지수를 산출하였다. 2018년부터 2022년까지 최근 5년 동안의 충남지역의 대설피해를 기준으로 PSR(Pressure Index, State Index, Response Index)과 DPSIR(Driver force Index, Pressure Index, State Index, Impact Index, Response Index) 방법을 이용하여 산출한 지수를 비교한 결과 DPSIR(Driver force Index, Pressure Index, State Index, Impact Index, Response Index) 방법을 이용하여 산출된 취약성 지수가 더 신뢰할 수 있는 결과를 보였다. 본 연구의 결과 대설피해 발생 시 대설 위험지수가 높은 지역을 선제적으로 대비할 수 있고 효율적인 제설대응체계를 구축할 수 있을 것으로 기대된다.

• Geotechnical Engineering
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• v.4 no.2
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• pp.15-24
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• 1988

To identify the stability of cantilever retaining wall in safe state by the deterministic method, these potential modes of such geotechnical failures as bearing capacity, horizontal sliding and overturning are analysed using Advanced First Order Second Moment (AFOSM) method. All design variables are assumed of the normal distribution and to be statistically independent. Considering the correlations between the single modes, structural system reliability index is 2. 05. Even if the safety factors are larger than the required value in the codes' by the conventional deterministic method, the system reliability of this structure may not be Judged to be safe state since the system reliability index is much lower than general value of 3.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.721-723
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• 2014

본 논문은 선박내부의 센서데이터 이상감지를 위해 실시간 신뢰구간을 설정하고 신뢰구간을 초과하거나 미만이 되면 경보를 통해 관리자에게 알려주는 모니터링을 위한 신뢰구간 추정이다. 여기서, 이상 감지 예측의 정확도 향상을 위해 단순지수평활법과 이동평균법의 평균제곱오차를 비교 평가 하였다. 실험결과, 이동평균법의 평균제곱오차가 단순지수평활법 보다 적게 나와 선박 내부 모니터링을 위한 신뢰구간은 이동평균법을 적용하였다.

• Journal of the Korean GEO-environmental Society
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• v.15 no.2
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• pp.5-15
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• 2014

Target reliability index in the limit state design indicated the safety margin and it is important to determine the partial factor. To determine the target reliability index which is needed in the limit state design, the six design and construction case histories of gravel compaction piles (GCP) were investigated. The limit state functions were defined by bulging failure for the major failure mode of GCP. The reliability analysis were performed using the first order reliability method (FORM) and the reliability index was calculated for each ultimate bearing capacity formulation. The reliability index of GCP tended to be penportional to the safety factor of allowable stress design and average value was ${\beta}$=2.30. Reliability level that was assessed by reliability analysis and target reliability index for existing structure foundations were compared and analyzed. As a result, The GCP was required a relatively low level of safety compared with deep and shallow foundations and the currd t reliability level were similar to the target reliability in the reinforced earth retaining-wall and soil-nailing. Therefore the target reliability index of GCP suggested as ${\beta}_T$=2.33 by various literatures together with the computed reliability level in this study.

• Journal of Applied Reliability
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• v.1 no.1
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• pp.55-63
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• 2001

In this paper, we utilize the asymptotic variance of $C_{pk}$ to propose a two-sided confidence interval based on percentile-t bootstrap method. This confidence interval is compared with the ones based on the standard and percentile bootstrap methods. Simulation results show that percentile-t bootstrap method is preferred to other methods for constructing the confidence interval.l.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.454-460
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• 2021

This study attempted to empirically analyze how the use of portal news is related with user's social credibility levels. 1100 subjects were sampled and online-surveyed. The amount of news usage and level of social credibility were measured respectively by the PNRBS(Portal News Readership Behavior Score) and SCI(Social Credibility Index) which were developed by the researcher. The results show that the relationship between scocial credibility and portal new use is not a linear but some V type. In terms of the mean score of social credibility index, non-portal news user is the highest while the light user is the lowest and the heavy user is the second highest.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.187-194
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• 2016

It is necessary to determine reliability indexes of existing railway bridges prior to setting up a proper target reliability index that can be used to introduce a reliability based limit state design method to design practice. Reliability is evaluated for a six PSC-I girder railway bridge, which is one of many representative types of double-track railway bridges. The reliability assessment is carried out for an edge girder subjected to bending moment. In the assessment, the flexural resistance and the fixed-load effect were obtained using existing statistical values from previous research on the introduction of limit state design to road bridge design. On the other hand, the live-load effect was determined using statistical values obtained from field measurement for the Joong-ang corridor, on which heavy freight trains are frequently passing. The reliability assessment is performed by AFOSM(Advanced First Order Second Moment method) for the limit state equation, and a sensitivity analysis for the reliability is performed for each factor of the load and resistance effects.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.641-648
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• 2022

In this study, the performance of the NHPP software reliability model with exponential distribution (Exponential Basic, Inverse Exponential, Lindley, Rayleigh) characteristics was comparatively analyzed, and based on this, the optimal reliability model was also presented. To analyze the software failure phenomenon, the failure time data collected during system operation was used, and the parameter estimation was solved by applying the maximum likelihood estimation method (MLE). Through various comparative analysis (mean square error analysis, true value predictive power analysis of average value function, strength function evaluation, and reliability evaluation applied with mission time), it was found that the Lindley model was an efficient model with the best performance. Through this study, the reliability performance of the distribution with the characteristic of the exponential form, which has no existing research case, was newly identified, and through this, basic design data that software developers could use in the initial stage can be presented.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.421-429
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• 2006

This study was undertaken to develop an analysis model representing a reliable estimation of rigidity of Korean soft clay using an artificial neural network (ANN). Data for the model development were obtained through a laboratory study, and were used for training and verification. The coefficient of correlation between the measured and predicted data using the developed model was relatively high. It demonstrates the potential application of ANN for the reliable estimation of Korean soft clay rigidity while past attempts at building such a mathematical model have proved difficult.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.3
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• pp.224-229
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• 2009

Partial safety factors(PSFs) for Level I reliability based design of caisson type quay walls were calculated. First order reliability method(FORM) based PSFs are the functions of sensitivities of limit state function with respect to design random variables, target reliability index, characteristic values and first moment of random variables. Modified PSFs for water level and resilient water level are newly defined to keep consistency with the current design code. In the numerical example, PSFs were calculated by using a target reliability index. Seismic coefficient is defined to show extreme distribution. It was found that PSFs for seismic coefficient becomes smaller as the return period for design seismic coefficient grows longer.