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Showing 1 to 13 of 13 for “"Adjoint Sensitivity Analysis"”.
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Adjoint sensitivity analysis of the atmospheric impacts of combustion emissions
… is computationally expensive. Atmospheric adjoint modeling enables the calculation of receptor-oriented sensitivities of environmental metrics of interest to emissions, overcoming the numerical cost of conventional modeling. This thesis applies and further develops an existing adjoint of a …
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Adjoint sensitivity analysis of the intercontinental impacts of aviation emissions on air quality and health
… various locations and times, this study uses the adjoint model of GEOS-Chem, a chemical transport model. The adjoint method efficiently computes sensitivities of a few objective functions, such as aggregated PM concentration and human exposure to PM concentration, with respect to many input …
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Adjoint sensitivity analysis of the two-phase two-fluid model based on an approximate Riemann solver
… numerical solver (i.e. forward solver) and an adjoint sensitivity analysis framework for the two-phase two-fluid model are developed and verified. Both the numerical solver and the adjoint sensitivity analysis framework are based on an analytical analysis of the two-phase two-fluid model. The …
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Direct Sensitivity Analysis of Spatial Multibody Systems with Joint Friction
Sensitivity analysis is one of the most prominent gradient based optimization techniques for mechanical systems. Model sensitivities are the derivatives of the generalized coordinates defining the motion of the system in time with respect to the system design parameters. These sensitivities can be …
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Air pollution and early deaths in the United States : attribution of PM₂.₅ exposure to emissions species, time, location and sector
… species, time and location. We apply a long-term adjoint sensitivity analysis with population exposure to PM2 .5 in the contiguous US as the objective function, and calculate the four dimensional sensitivities (time and space) of PM2 .5 exposure with respect to each emissions species. …
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Coupled Adjoint-based Sensitivity Analysis using a FSI Method in Time Spectral Form
A time spectral and coupled adjoint based sensitivity analysis of rotor blade is carried out in this study. The time spectral method is an efficient technique to solve unsteady periodic problems by transforming unsteady equation of motion to a steady state one. Due to the availability of the …
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Design of functionally graded compliant mechanisms using topology optimization
… asymptotes (MMA) is used in conjunction with adjoint sensitivity analysis to find the optimal distribution of material properties. Functionally graded materials (FGMs) have material properties that vary based on spatial position. Here, FGMs are implemented using two different resource …
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Application of the complex step method to chemistry-transport modeling
Sensitivity analysis in atmospheric chemistry-transport modeling is used to develop understanding of the mechanisms by which emissions affect atmospheric chemistry and composition, to quantify the marginal impact of emissions on air quality, and for other applications including improving estimates …
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Adjoint-based space-time adaptive solution algorithms for sensitivity analysis and inverse problems
… mesh motion equations, or inconsistencies in the sensitivity equations between subdomains with different refinement levels. However, this comes at the cost of low computational efficiency. More efficient computations are possible through judicious use of adaptive mesh refinement, adaptive time …
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Modeling, Sensitivity Analysis, and Optimization of Hybrid, Constrained Mechanical Systems
… framework for performing the direct and the adjoint sensitivity analysis for general hybrid systems associated with general cost functions. The mathematical framework computes the jump sensitivity matrix of the direct sensitivities which is found by computing the Jacobian of the jump …
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Computational Tools for Chemical Data Assimilation with CMAQ
… for atmospheric pollution studies. CMAQ-ADJ, the adjoint model of CMAQ, offers new analysis capabilities such as receptor-oriented sensitivity analysis and chemical data assimilation. This thesis presents the construction, validation, and properties of new adjoint modules in CMAQ, and illustrates …
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Nonlinear structural design using multiscale topology optimization
… transient dynamics. We systematically develop adjoint sensitivity analyses and incorporate them into gradient-based optimization update algorithms. In the multiscale elastostatic formulation, we design composite material microstructures by combining topology optimization, computational …
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Efficient Computational Tools for Variational Data Assimilation and Information Content Estimation
… more challenging. The construction of an adjoint model ( capable of efficiently computing sensitivities of a few model outputs with respect to many input parameters ) is a difficult, labor intensive, and error prone task. This work develops adjoint systems for two of the most widely used …