Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for processing database system processes seismic wave data using database queries. The seismic wave data is obtained from sensors of a reflection seismology survey. The seismic wave data is distributed among nodes of the parallel processing database system. Computations of processing the seismic wave data are performed using relational database queries that execute on the nodes in parallel. These computations performed by the queries include generating a starting Earth model of an area surveyed, and performing iterations of solving a forward problem of generating seismic wave patterns from the starting Earth model, performing local optimization that modifies the starting Earth model, and providing the modified Earth model as input to the forward problem in a next iteration.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for predicting traffic patterns. One of the methods includes receiving a velocity distribution for a road segment, wherein the velocity distribution includes, for each velocity interval, a count of how many velocity observations have a velocity measurement within the velocity interval, wherein each velocity observation has one or more features describing conditions under which the velocity observation was made. A mixture model having K component distributions is generated for the velocity distribution. A decision tree is generated from the K component distributions and a rule is generated from a particular leaf of the decision tree, wherein the rule maps one or more features for the road segment to one of the K component distributions according to a path from the root of the decision tree to the particular leaf.