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We apply a model checker to the problem of test generation using a new application of mutation analysis. We define syntactic operators, each of which produces a slight variation on a given model. The operators define a form of mutation analysis at the level of the model checker specification. A model checker generates countersamples which distinguish the variations from the original specification. The countersamples can easily be turned into complete test cases, that is, with inputs and expected results. We define two classes of operators: those that produce test cases from which a correct implementation must differ, and those that produce test cases with which it must agree. There are substantial advantages to combining a model checker with mutation analysis. First, test case generation is automatic; each countersample is a complete test case. Second, in sharp contrast to program-based mutation analysis, equivalent mutant identification is also automatic. We apply our method to an example specification and evaluate the resulting test sets with coverage metrics on a Java implementation.

Using Model Checking to Generate Tests from Specifications | NIST

We investigated the aggregation of PMN from 20 psoriasis patients (PP) and 12 health persons (HP) to PAF and the effect of PAF antagonist BN 52021 on the aggregation. PAF induced a dose dependent aggregative response of polymorphonuclear neutrophils (PMN) from PP and HP. The aggregative responses of PMN from PP to lower concentrations of PAF were increased (P < 0.05) and to higher concentrations of PAF were not different to that of PMN from HP. BN 52021 could time- and dose-dependently inhibit the aggregation of PMN from PP and HP to PAF, and their IC50 was 1.3 x 10(-6) mol and 1.2 x 10(-6) mol respectively. It is suggested that PAF and PMN play an important pathophysiological role in the development of psoriasis, and application of PAF antagonists may be a new and effective approach to the management of psoriasis.

Effect of BN52021 on platelet activating factor induced aggregation of psoriatic polymorphonuclear neutrophils

We study the problem of learning sequential top-down tree-to-word transducers stws. First, we present a Myhill-Nerode characterization of the corresponding class of sequential tree-to-word transformations ${\mathcal{STW}}$ . Next, we investigate what learning of stws means, identify fundamental obstacles, and propose a learning model with abstain. Finally, we present a polynomial learning algorithm.

/pdf/learning-sequential-tree-to-word-transducers-8kbfddnvim.pdf

Learning Sequential Tree-to-Word Transducers

Call a string-to-string function regular if it can be realised by one of the following equivalent models: mso transductions, two-way deterministic automata with output, and streaming transducers with registers. This paper proposes to treat origin information as part of the semantics of a regular string-to-string function. With such semantics, the model admits a machine-independent characterisation, Angluin-style learning in polynomial time, as well as effective characterisations of natural subclasses such as one-way transducers or first-order definable transducers.

/pdf/transducers-with-origin-information-2hm03t2fj2.pdf

Transducers with Origin Information

Visibly pushdown automata have been recently introduced by Alur and Madhusudan as a subclass of pushdown automata. This class enjoys nice properties such as closure under all Boolean operations and the decidability of language inclusion. Along the same line, we introduce here visibly pushdown transducers as a subclass of pushdown transducers. We study properties of those transducers and identify subclasses with useful properties like decidability of type checking as well as preservation of regularity of visibly pushdown languages.

Visibly pushdown transducers

Visibly pushdown transducers (VPTs) form a strict subclass of pushdown transducers (PTs) that extends finite state transducers with a stack. Like visibly pushdown automata, the input symbols determine the stack operations. It has been shown that visibly pushdown languages form a robust subclass of context-free languages. Along the same line, we show that word transductions defined by VPTs enjoy strong properties, in contrast to PTs. In particular, functionality is decidable in PTIME, k-valuedness is in NPTIME and equivalence of (non-deterministic) functional VPTs is EXPTIME-C. Those problems are undecidable for PTs. Output words of VPTs are not necessarily well-nested. We identify a general subclass of VPTs that produce well-nested words, which is closed by composition, and for which the type checking problem is decidable.

https://hal.inria.fr/inria-00492241/document

Properties of visibly pushdown transducers

Any two-way finite state automaton is equivalent to some one-way finite state automaton This well-known result, shown by Rabin and Scott and independently by Shepherd son, states that two-way finite state automata (even non-deterministic) characterize the class of regular languages It is also known that this result does not extend to finite string transductions: (deterministic) two-way finite state transducers strictly extend the expressive power of (functional) one-way transducers In particular deterministic two-way transducers capture exactly the class of MSO-transductions of finite strings In this paper, we address the following definability problem: given a function defined by a two-way finite state transducer, is it definable by a one-way finite state transducer? By extending Rabin and Scott's proof to transductions, we show that this problem is decidable Our procedure builds a one-way transducer, which is equivalent to the two-way transducer, whenever one exists

From Two-Way to One-Way Finite State Transducers

This paper presents the Monotone-Pruning algorithm (MP) for computing the minimal coverability set of Petri nets. The original Karp and Miller algorithm (K&M) unfolds the reachability graph of a Petri net and uses acceleration on branches to ensure termination. The MP algorithm improves the K&M algorithm by adding pruning between branches of the K&M tree. This idea was first introduced in the Minimal Coverability Tree algorithm (MCT), however it was recently shown to be incomplete. The MP algorithm can be viewed as the MCT algorithm with a slightly more aggressive pruning strategy which ensures completeness. Experimental results show that this algorithm is a strong improvement over the K&M algorithm.

/pdf/minimal-coverability-set-for-petri-nets-karp-and-miller-4gqwgckg2j.pdf

Minimal coverability set for petri nets: Karp and Miller algorithm with pruning

This paper presents the Monotone-Pruning algorithm (MP) for computing the minimal coverability set of Petri nets. The original Karp and Miller algorithm (K&M) unfolds the reachability graph of a Petri net and uses acceleration on branches to ensure termination. The MP algorithm improves the K&M algorithm by adding pruning between branches of the K&M tree. This idea was first introduced in the Minimal Coverability Tree algorithm (MCT), however it was recently shown to be incomplete. The MP algorithm can be viewed as the MCT algorithm with a slightly more aggressive pruning strategy which ensures completeness. Experimental results show that this algorithm is a strong improvement over the K&M algorithm. © 2011 Springer-Verlag.

/pdf/minimal-coverability-set-for-petri-nets-karp-and-miller-1er5rij41i.pdf

Frédéric Servais

Papers

Visibly pushdown transducers

Properties of visibly pushdown transducers

From Two-Way to One-Way Finite State Transducers

Minimal coverability set for petri nets: Karp and Miller algorithm with pruning

Minimal coverability set for Petri nets: Karp and Miller algorithm with pruning