Pushdown automaton

About: Pushdown automaton is a research topic. Over the lifetime, 1868 publications have been published within this topic receiving 35399 citations.

A regularity test for pushdown machines

Abstract: It is possible to test a deterministic pushdown machine to determine if the language it recognizes is regular.

Statically-directed dynamic automated test generation

Abstract: We present a new technique for exploiting static analysis to guide dynamic automated test generation for binary programs, prioritizing the paths to be explored. Our technique is a three-stage process, which alternates dynamic and static analysis. In the first stage, we run dynamic analysis with a small number of seed tests to resolve indirect jumps in the binary code and build a visibly pushdown automaton (VPA) reflecting the global control-flow of the program. Further, we augment the computed VPA with statically computable jumps not executed by the seed tests. In the second stage, we apply static analysis to the inferred automaton to find potential vulnerabilities, i.e., targets for the dynamic analysis. In the third stage, we use the results of the prior phases to assign weights to VPA edges. Our symbolic-execution based automated test generation tool then uses the weighted shortest-path lengths in the VPA to direct its exploration to the target potential vulnerabilities. Preliminary experiments on a suite of benchmarks extracted from real applications show that static analysis allows exploration to reach vulnerabilities it otherwise would not, and the generated test inputs prove that the static warnings indicate true positives.

The Equivalence Problem for Deterministic Pushdown Automata is Decidable

Abstract: The equivalence problem for deterministic pushdown automata is shown to be decidable. We exhibit a complete formal system for deducing equivalent pairs of deterministic rational series on the alphabet associated with a dpda M.

Solving games without determinization

Abstract: The synthesis of reactive systems requires the solution of two-player games on graphs with ω-regular objectives. When the objective is specified by a linear temporal logic formula or nondeterministic Buchi automaton, then previous algorithms for solving the game require the construction of an equivalent deterministic automaton. However, determinization for automata on infinite words is extremely complicated, and current implementations fail to produce deterministic automata even for relatively small inputs. We show how to construct, from a given nondeterministic Buchi automaton, an equivalent nondeterministic parity automaton $\ensuremath {\cal P}$ that is good for solving games with objective $\ensuremath {\cal P}$. The main insight is that a nondeterministic automaton is good for solving games if it fairly simulates the equivalent deterministic automaton. In this way, we omit the determinization step in game solving and reactive synthesis. The fact that our automata are nondeterministic makes them surprisingly simple, amenable to symbolic implementation, and allows an incremental search for winning strategies.

The equivalence problem for deterministic finite-turn pushdown automata

Abstract: It is proved that there is an effective procedure for deciding whether two deterministic finite-turn pushdown automata are equivalent.