The use of adjoint modeling for acoustic inversion is investigated. An adjoint model is derived from a linearized forward propagation model to propagate data-model misfit at the observation points back through the medium to the medium perturbations not being accounted for in the model. This adjoint model can be used to aid in inverting for these unaccounted medium perturbations. Adjoint methods...

We present a framework of sequential action control (SAC) for stabilization systems partial differential equations which can be posed as abstract semilinear problems in Hilbert spaces. follow late-lumping approach and show that the explicitly obtained from variational principles using adjoint information. Moreover, we analyze closed-loop system SAC feedback linear problem with quadratic stage c...

A “Composition map” is constructed, leaning heavily on earlier work Fittouhi and Joseph (2023) [5], [6]). It defines a composition tableau which recovers the “canonical” Weierstrass section e+V described in first paper above. Moreover without reference to this work, it then shown that indeed section. This results huge simplification. one may read off from “VS quadruplets” of second above papers...

An adjoint model for the internationally used Community Multiscale Air Quality (CMAQ) modeling platform of the U.S. EPA is developed. The adjoint version for CMAQ (CMAQ-ADJ) provides the user community with forward (decoupled direct method or DDM) and backward (adjoint) sensitivity analysis capabilities. Current implementation is for gas-phase processes. Discrete adjoints are implemented for al...

This paper describes a derivation of the adjoint low Mach number equations and their implementation and validation within a global mode solver. The advantage of using the low Mach number equations and their adjoints is that they are appropriate for flows with variable density, such as flames, but do not require resolution of acoustic waves. Two versions of the adjoint are implemented and assess...

Let H be a symmetric operator in a separable Hilbert space H. Suppose that H has some gap J . We shall investigate the question about what spectral properties the self{adjoint extensions of H can have inside the gap J and provide methods how to construct self{adjoint extensions of H with prescribed spectral properties inside J . Under some weak assumptions about the operator H which are satised...

S U M M A R Y We determine centroid-moment tensor (CMT) solutions by minimizing waveform differences between observed and simulated seismograms based on an adjoint method. Synthetic seismograms and Fréchet derivatives are calculated based on a spectral-element method. The non-linear adjoint CMT inversion algorithm requires three simulations for each iteration: one ‘forward’ simulation to obtain...

Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Abstract We present the adjoint of the global chemical transport model GEOS-Chem, focusing on the chemical and thermodynamic relationships between sulfate – ammonium – nitrate aerosols and their gas-phase precursors. The adjoint...