SEARCH ALGORITHMS FOR SATISFIABILITY PROBLEMS IN COMBINATIONAL SWITCHING CIRCUITS by João Paulo Marques da Silva Chair: Karem A. Sakallah A number of tasks in computer-aided analysis of combinational circuits, including test pattern generation, timing analysis, delay fault testing and logic verification, can be viewed as particular formulations of the satisfiability problem (SAT). The first pur...

The random k-SAT model is the most important and well-studied distribution over k-SAT instances. It is closely connected to statistical physics; it is used as a testbench for satisfiablity algorithms, and lastly average-case hardness over this distribution has also been linked to hardness of approximation via Feige’s hypothesis. In this paper, we prove that any Cutting Planes refutation for ran...

Many verification tools used in practice rely on sophisticated SAT and SMT solvers. These reasoning engines are assumed and expected to be correct, but, in general, too complex to be fully verified. Therefore, effective testing techniques have to be employed. In this paper, we show how to employ model-based testing (MBT) to test sequences of application programming interface (API) calls and dif...

BACKGROUND The use of zidovudine is associated with a loss of subcutaneous adipose tissue (SAT). We assessed if zidovudine treatment also affects visceral adipose tissue (VAT) and if uridine supplementation abrogates the adverse effects of zidovudine on VAT. METHODS Rats were fed zidovudine for 21 weeks with or without simultaneous uridine supplementation. Control animals did not receive zido...

Understanding the complex dynamics of the atmosphere is of paramount interest due to its impact in the entire climate system and in human society. Here we focus on identifying, from data, the geographical regions which have similar atmospheric properties. We study surface air temperature (SAT) time series with monthly resolution, recorded at a regular grid covering the Earth surface. We conside...

This paper presents an elegant algorithm for existential quantifier elimination using incremental SAT solving. This approach contrasts with existing techniques in that it is based solely on manipulating the SAT instance rather than requiring any reengineering of the SAT solver or needing an auxiliary data-structure such as a BDD. The algorithm combines model enumeration with the generation of s...

In Boolean logic, a formula is satisfiable if a variable assignment exists that will make the formula equivalent to true, and the propositional satisfiability problem (SAT) is to determine if a given formula is satisfiable. SAT is one of the most fundamental problems in computer science, and since many relevant combinatorial problems can be encoded into SAT, it is of substantial theoretical and...

With the flourishing development of efficient SAT-solvers, bounded model checking (BMC) has proven to be an extremely powerful symbolic model checking technique. In this paper, we address the problem of applying BMC to concurrent systems involving the interaction of multiple processes running in parallel. We adapt the BMC framework to the context of CSP and FDR yielding bounded refinement check...

Introduction Algorithm portfolio methods (Huberman, Lukose, and Hogg 1997) use information about solvers and problem instances to allocate computational resources among multiple solvers, attempting to maximize the time spent on those well suited to each instance. Portfolio methods such as SATzilla (Xu et al. 2008) have proved increasingly effective in satisfiability. An algorithm portfolio must...

Cellular Automata are a powerful formal model for describing physical and computational processes. Qualitative analysis of Cellular Automata is in general a hard problem. In this paper we will investigate the applicability of modern SAT solvers to this problem. For this purpose we will define an encoding of reachability problems for Cellular Automata into SAT. The encoding is built in a modular...