Whereas different hydrometeor types cannot be readily distinguished using radar reflectivity alone, this paper shows how the differential reflectivity available from dual-polarization radars can be used as an indicator of hydrometeor type (when supported by reflectivity factor also), and that the spatial variability of differential reflectivity is a useful addition. Various hydrometeor types, g...

Zchaff is an implementation of the well known Chaff algorithm [6]. It participated in the SAT 2002 Competition and won the Best Complete Solver in both industrial and handmade benchmark categories. It is a popular solver and can be compiled into a linkable library for easy integration with user applications. Successful integration examples include the BlackBox AI planner [1], NuSMV model checke...

The paper is concerned with the computational evaluation of a new branching heuristic, called reverse assignment sequence (RAS), for evolved DPLL Satisfiability solvers. Such heuristic, like several other recent ones, is based on the history of the conflicts obtained during the solution of an instance. A score is associated to each literal. When a conflict occurs, some scores are incremented wi...

In this paper I describe experiments in the application of dynamic restarts used in heuristic satisfiability algorithms. By modifying a state-of-the-art SAT solver, zchaff, I test three proposed modifications to typical restart policies: exponentially increasing restart thresholds, restricting restarts to occur only at certain critical points, and the addition of transient randomness after a re...

We propose a new decision heuristic for DPLL-based propositional SAT solvers. Its essence is that both the initial and the conflict clauses are arranged in a list and the next decision variable is chosen from the top -most unsatisfied clause. Various methods of initially organizing the list and moving the clauses within it are studied. Our approach is an extension of one used in Berkmin, and ad...

We design an evolutionary heuristic for the combinatorial problem of de-novo DNA assembly with short, overlapping, accurately sequenced single DNA reads of uniform length, from both strands of a genome without long repeated sequences. The representation of a candidate solution is a novel segmented permutation: an ordering of DNA reads into contigs, and of contigs into a DNA scaffold. Mutation a...

Rsat is a DPLL–based solver that inherits many of the effective techniques introduced by MiniSat [3, 4] and Zchaff [6]. Rsat employs three improvements that have proven quite effective empirically. First, it employs techniques for reducing the time spent on Boolean constraint propagation. Next, it introduces a new technique that enables the solver to better focus on subproblems. Finally, Rsat e...

This paper describes the integration of zChaff and MiniSat, currently two leading SAT solvers, with Isabelle/HOL. Both SAT solvers generate resolution-style proofs for (instances of) propositional tautologies. These proofs are verified by the theorem prover. The presented approach significantly improves Isabelle’s performance on propositional problems, and exhibits counterexamples for unprovabl...

The variable branching heuristics used in the most recent and most effective SAT solvers, including zChaff and BerkMin, can be viewed as consisting of a simple mechanism for rewarding the variables participating in conflicts during the search process. In this paper we propose to extend the simple rewarding mechanism used in zChaff and BerkMin, and develop different rewarding mechanisms based on...