방법 비교

	하이브리드 신뢰도 분석	이차 신뢰도 방법 (SORM)
분야	실험설계	신뢰성공학
계열	Process / pipeline	Process / pipeline
기원 연도	1990s–2000s (consolidated formulation ~2000–2006)	1979
창시자	Xiaoping Du, Achintya Haldar, and others; synthesized across structural and mechanical engineering communities	Bernd Fiessler
유형	Quantitative reliability / uncertainty analysis method	Reliability analysis method
원전	Du, X., Sudjianto, A., & Huang, B. (2006). Reliability-Based Design With the Mixture of Random and Interval Variables. Journal of Mechanical Design, 127(6), 1068–1076.	Fiessler, B., Neumann, H. J., & Rackwitz, R. (1979). Quadratic limit states in structural reliability. Journal of the Engineering Mechanics Division, 105(4), 661-676.
별칭	HRA, hybrid uncertainty reliability, combined reliability analysis, probabilistic-possibilistic reliability analysis	SORM, Second-order approximation
관련	4	4
요약	Hybrid Reliability Analysis (HRA) quantifies the probability that an engineering system will perform its intended function when uncertain inputs are of two fundamentally different kinds: aleatory uncertainties (natural randomness, modelled with probability distributions) and epistemic uncertainties (lack of knowledge, modelled with intervals or fuzzy sets). By treating both uncertainty types simultaneously rather than collapsing them into a single probabilistic framework, HRA produces more truthful reliability estimates in design, structural, and systems engineering problems.	The Second-Order Reliability Method (SORM) is an extension of FORM that improves failure probability estimates by accounting for the curvature of the limit-state surface at the design point. Introduced by Fiessler, Neumann, and Rackwitz in 1979, SORM provides more accurate approximations for nonlinear failure surfaces while remaining computationally efficient. It has become the standard refinement when FORM accuracy is insufficient.