Automatic traveltime inversion via sparse decomposition of seismic data

We have developed an automatic traveltime inversion (ATI) method to estimate the macrovelocity model from reflection seismic data. First, we extract the kinematic information (i.e., source/receiver ray parameters, traveltime, and source/receiver coordinates) of locally coherent events using a sparse-decomposition method. And then we evaluate a new strategy to calculate the reflection traveltime residual based on a ray-intersection criterion, eliminating the influence of seismic amplitude to the estimation of the traveltime residual. The velocity model can be updated iteratively by minimizing the traveltime residual functional with a gradient-based method. To obtain a smooth gradient free of artifacts, we first estimate the high-wavenumber components of the functional gradient with a total variation (TV) regularization method and then subtract it from the full gradient. Because the reflection traveltime residual calculation and velocity update are fully automated procedures, the proposed traveltime inversion method is referred to as ATI. We determine with 2D synthetic and field examples that ATI does not need a good starting model. Furthermore, it requires neither low-frequency seismic data nor long-offset acquisition. Nevertheless, the proposed traveltime residual calculation strategy is only valid for the 2D case, which limits its 3D applicability. We explore a possible solution for 3D extension.

COMPLETE INTERSECTIONS IN BINOMIAL AND LATTICE IDEALS

For the family of graded lattice ideals of dimension 1, we establish a complete intersection criterion in algebraic and geometric terms. In positive characteristic, it is shown that all ideals of this family are binomial set-theoretic complete intersections. In characteristic zero, we show that an arbitrary lattice ideal which is a binomial set-theoretic complete intersection is a complete intersection.

Study on Intersection Criterion of MEFP Warhead to Target

Putting forward the straight-line trajectory of MEFP （multi-explosively formed penetrators, also called attack unit） in the target coordinate by means of building ground coordinate and target coordinate and the conversion of ground coordinate to target coordinate in the Area Blank off Weapon System. According to the intersection criterion that there are only two points between the attack unit straight-line trajectory and the cylindrical surface of the target, whether attack unit hits the target or not is decided. The intersection criterion is applied on the simulation of all kinds of different distributed plans.