1,268 research outputs found
Structural Invariants for Parametric Verification of Systems with Almost Linear Architectures
We consider concurrent systems consisting of a finite but unknown number of components , that are replicated instances of a given set of finite state automata. The components communicate by executing interactions which are simultaneous atomic state changes of a set of components. We specify both the type of interactions (e.g. rendezvous , broadcast) and the topology (i.e. architecture) of the system (e.g. pipeline, ring) via a decidable interaction logic, which is embedded in the classical weak sequential calculus of one successor (WS1S). Proving correctness of such system for safety properties , such as deadlock freedom or mutual exclusion, requires the inference of an induc-tive invariant that subsumes the set of reachable states and avoids the unsafe states. Our method synthesizes such invariants directly from the formula describing the interactions , without costly fixed point iterations. We applied our technique to the verification of several textbook examples, such as dining philosophers, mutual exclusion protocols and concurrent systems with preemption and priorities
Parameterized Synthesis
We study the synthesis problem for distributed architectures with a
parametric number of finite-state components. Parameterized specifications
arise naturally in a synthesis setting, but thus far it was unclear how to
detect realizability and how to perform synthesis in a parameterized setting.
Using a classical result from verification, we show that for a class of
specifications in indexed LTL\X, parameterized synthesis in token ring networks
is equivalent to distributed synthesis in a network consisting of a few copies
of a single process. Adapting a well-known result from distributed synthesis,
we show that the latter problem is undecidable. We describe a semi-decision
procedure for the parameterized synthesis problem in token rings, based on
bounded synthesis. We extend the approach to parameterized synthesis in
token-passing networks with arbitrary topologies, and show applicability on a
simple case study. Finally, we sketch a general framework for parameterized
synthesis based on cutoffs and other parameterized verification techniques.Comment: Extended version of TACAS 2012 paper, 29 page
Architectures in parametric component-based systems: Qualitative and quantitative modelling
One of the key aspects in component-based design is specifying the software
architecture that characterizes the topology and the permissible interactions
of the components of a system. To achieve well-founded design there is need to
address both the qualitative and non-functional aspects of architectures. In
this paper we study the qualitative and quantitative formal modelling of
architectures applied on parametric component-based systems, that consist of an
unknown number of instances of each component. Specifically, we introduce an
extended propositional interaction logic and investigate its first-order level
which serves as a formal language for the interactions of parametric systems.
Our logics achieve to encode the execution order of interactions, which is a
main feature in several important architectures, as well as to model recursive
interactions. Moreover, we prove the decidability of equivalence,
satisfiability, and validity of first-order extended interaction logic
formulas, and provide several examples of formulas describing well-known
architectures. We show the robustness of our theory by effectively extending
our results for parametric weighted architectures. For this, we study the
weighted counterparts of our logics over a commutative semiring, and we apply
them for modelling the quantitative aspects of concrete architectures. Finally,
we prove that the equivalence problem of weighted first-order extended
interaction logic formulas is decidable in a large class of semirings, namely
the class (of subsemirings) of skew fields.Comment: 53 pages, 11 figure
Transfer Function Synthesis without Quantifier Elimination
Traditionally, transfer functions have been designed manually for each
operation in a program, instruction by instruction. In such a setting, a
transfer function describes the semantics of a single instruction, detailing
how a given abstract input state is mapped to an abstract output state. The net
effect of a sequence of instructions, a basic block, can then be calculated by
composing the transfer functions of the constituent instructions. However,
precision can be improved by applying a single transfer function that captures
the semantics of the block as a whole. Since blocks are program-dependent, this
approach necessitates automation. There has thus been growing interest in
computing transfer functions automatically, most notably using techniques based
on quantifier elimination. Although conceptually elegant, quantifier
elimination inevitably induces a computational bottleneck, which limits the
applicability of these methods to small blocks. This paper contributes a method
for calculating transfer functions that finesses quantifier elimination
altogether, and can thus be seen as a response to this problem. The
practicality of the method is demonstrated by generating transfer functions for
input and output states that are described by linear template constraints,
which include intervals and octagons.Comment: 37 pages, extended version of ESOP 2011 pape
Structural Invariants for the Verification of Systems with Parameterized Architectures
We consider parameterized concurrent systems consisting of a finite but
unknown number of components, obtained by replicating a given set of finite
state automata. Components communicate by executing atomic interactions whose
participants update their states simultaneously. We introduce an interaction
logic to specify both the type of interactions (e.g.\ rendez-vous, broadcast)
and the topology of the system (e.g.\ pipeline, ring). The logic can be easily
embedded in monadic second order logic of finitely many successors, and is
therefore decidable.
Proving safety properties of such a parameterized system, like deadlock
freedom or mutual exclusion, requires to infer an inductive invariant that
contains all reachable states of all system instances, and no unsafe state. We
present a method to automatically synthesize inductive invariants directly from
the formula describing the interactions, without costly fixed point iterations.
We experimentally prove that this invariant is strong enough to verify safety
properties of a large number of systems including textbook examples (dining
philosophers, synchronization schemes), classical mutual exclusion algorithms,
cache-coherence protocols and self-stabilization algorithms, for an arbitrary
number of components.Comment: preprint; to be published in the proceedings of TACAS2
SAVCBS 2003: Specification and Verification of Component-Based Systems
These are the proceedings for the SAVCBS 2003 workshop. This workshop was held at ESEC/FSE 2003 in Helsinki Finland in September 2003
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