Abstract. Reverse-time migration (RTM) of teleseismic converted and free-surface reflected phases has been successful in helping to constrain the structure of the crust and upper mantle, but its accuracy is to a large extent determined by the background velocity model used in the underlying wave propagation. To this end, we develop a technique for RTM based wave-equation reflection tomography i...

Hydrocarbon production modifies the stress conditions in the subsurface and changes the model parameters previously estimated from the prospect. The capability to remotely monitor the changes in the reservoir using seismic data has strategic importance since it allows us to infer fluid movement and evolution of stress conditions, which are key factors to enhance recovery and reduce uncertainty ...

We propose to induce QCD by fermions in the adjoint representation of the gauge group SU(Nc) on the lattice. We consider various types of lattice fermions: chiral, Kogut–Susskind and Wilson ones. Using the mean field method we show that a first order large-N phase transition occurs with decreasing fermion mass. We conclude, therefore, that adjoint fermions induce QCD. We draw the same conclusio...

We present a method for estimating spatial and temporal numerical errors in scalar outputs of unsteady fluid dynamics simulations using a continuous-in-time adjoint solution and general time-integration methods. A continuous formulation decouples the primal and adjoint temporal discretizations and allows the use of standard time-integration schemes for the adjoint. For non-variational methods, ...

A synthesis of results of the recently introduced paradigm of multi-adjoint logic programming is presented. These results range from a proof theory together with some (quasi)completeness results to general termination results, and from the neural-like implementation of its fix-point semantics to the more general biresiduated multi-adjoint logic programming and its relationship with other approa...

We present a computationally efficient and accurate adjoint method for calculating coupled sensitivities of complex frequency-domain excitation and emission fluence to any underlying optical parameters in highly scattering media. The method is shown to be general and accurate. Novel vectorized implementations for finite element global matrix assembly and adjoint sensitivity calculations are sho...

In this paper we present a discrete adjoint approach for the optimization of unsteady, turbulent flows. While discrete adjoint methods usually rely on the use of the reverse mode of Automatic Differentiation (AD), which is difficult to apply to complex unsteady problems, our approach is based on the discrete adjoint equation directly and can be implemented efficiently with the use of a sparse f...

A set of four-dimensional variational data assimilation (4D-Var) experiments were conducted using both a standard method and an incremental method in an identical twin framework. The full physics adjoint model of the Florida State University global spectral model (FSUGSM) was used in the standard 4D-Var, while the adjoint of only a few selected physical parameterizations was used in the increme...