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نتیجه جستجو - کمیت عدم قطعیت

تعداد مقالات یافته شده: 2
ردیف عنوان نوع
1 Intrusive acceleration strategies for uncertainty quantificationfor hyperbolic systems of conservation laws
استراتژی های شتابزنی سرعتی برای تعیین کمیت عدم اطمینان برای سیستم هایپربولیک قوانین حفاظت-2020
Methods for quantifying the effects of uncertainties in hyperbolic problems can be divided into intrusive and non-intrusive techniques. Non-intrusive methods allow the usage of a given deterministic solver in a black-box manner, while being embarrassingly parallel. On the other hand, intrusive modifications allow for certain acceleration techniques. Moreover, intrusive methods are expected to reach a given accuracy with a smaller number of unknowns compared to non-intrusive techniques. This effect is amplified in settings with high dimensional uncertainty. A downside of intrusive methods is the need to guarantee hyperbolicity of the resulting moment system. In contrast to stochastic-Galerkin (SG), the Intrusive Polynomial Moment (IPM) method is able to maintain hyperbolicity at the cost of solving an optimization problem in every spatial cell and every time step. In this work, we propose several acceleration techniques for intrusive methods and study their advantages and shortcomings compared to the non-intrusive Stochastic Collocation method. When solving steady problems with IPM, the numerical costs arising from repeatedly solving the IPM optimization problem can be reduced by using concepts from PDE-constrained optimization. Integrating the iteration from the numerical treatment of the optimization problem into the moment update reduces numerical costs, while preserving local convergence. Additionally, we propose an adaptive implementation and efficient parallelization strategy of the IPM method. The effectiveness of the proposed adaptations is demonstrated for multi-dimensional uncertainties in fluid dynamics applications, resulting in the observation of requiring a smaller number of unknowns to achieve a given accuracy when using intrusive methods. Furthermore, using the proposed acceleration techniques, our implementation reaches a given accuracy faster than Stochastic Collocation.
Keywords: Uncertainty quantification | Hyperbolic conservation laws | Intrusive | Stochastic-Galerkin | Collocation | Intrusive Polynomial Moment Method
مقاله انگلیسی
2 A series of forecasting models for seismic evaluation of dams based on ground motion meta-features
مجموعه ای از مدل های پیش بینی برای ارزیابی لرزه ای سدها بر اساس ویژگی های متا حرکت زمین-2020
Uncertainty quantification (UQ) due to seismic ground motions variability is an important task in risk-informed condition assessment of infrastructures. Since performing multiple dynamic analyses is computationally expensive, it is valuable to develop a series of forecasting models based on the unique ground motion characteristics. This paper discusses the application of six different machine learning techniques on forecasting the structural behavior of gravity dams. Various time-, frequency-, and intensity-dependent characteristics are extracted from ground motion signals and used in machine learning. A large set of about 2000 real ground motions are used, each includes about 35 meta-features. The major outcome of this study is to show the applicability of metamodeling- based UQ in seismic safety evaluation of dams. As an intermediary result, the advantages of different machine learning algorithms, as well as meta-feature selection possibility is discussed for the current dataset. This paper proposes a feasibility study to reduce the computational costs in UQ of large-scale infra-structural systems.
Keywords: Uncertainty quantification | Dams | Forecasting | Machine learning | Big data
مقاله انگلیسی
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بازدید امروز: 5065 :::::::: بازدید دیروز: 3097 :::::::: بازدید کل: 39332 :::::::: افراد آنلاین: 55