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 model is constructed from a combination of manually and automatically derived discrete adjoint algorithms and numerical solutions to continuous adjoint equations. Explicit inclu...

The optimal checkpointing algorithm (Griewank and Walther, 2000) minimizes the computational complexity of the adjoint state method. Applied to reverse time migration, optimal checkpointing eliminates (or at least drastically reduces) the need for disk i/o, which is quite extensive in more straightforward implementations. This paper describes optimal checkpointing in a form which applies both t...

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 ...

A generalization of the homogenization process needed for the neural implementation of multi-adjoint logic programming (a unifying theory to deal with uncertainty, imprecise data or incomplete information) is presented here. The idea is to allow to represent a more general family of adjoint pairs, but maintaining the advantage of the existing implementation recently introduced in [6]. The sound...

By a solution of () we mean a function x ∈ C[Tx,∞), Tx ≥ , which satisfies () on [Tx,∞). A solution is said to be nonoscillatory if x(t) =  for large t; otherwise, it is said to be oscillatory. Observe that if λ≥ , according to [, Theorem .], all nontrivial solutions of () satisfy sup{|x(t)| : t ≥ T} >  for T ≥ Tx, on the contrary to the case λ < , when nontrivial solutions satisfy...