23 research outputs found
Weighted Modal Transition Systems
Specification theories as a tool in model-driven development processes of
component-based software systems have recently attracted a considerable
attention. Current specification theories are however qualitative in nature,
and therefore fragile in the sense that the inevitable approximation of systems
by models, combined with the fundamental unpredictability of hardware
platforms, makes it difficult to transfer conclusions about the behavior, based
on models, to the actual system. Hence this approach is arguably unsuited for
modern software systems. We propose here the first specification theory which
allows to capture quantitative aspects during the refinement and implementation
process, thus leveraging the problems of the qualitative setting.
Our proposed quantitative specification framework uses weighted modal
transition systems as a formal model of specifications. These are labeled
transition systems with the additional feature that they can model optional
behavior which may or may not be implemented by the system. Satisfaction and
refinement is lifted from the well-known qualitative to our quantitative
setting, by introducing a notion of distances between weighted modal transition
systems. We show that quantitative versions of parallel composition as well as
quotient (the dual to parallel composition) inherit the properties from the
Boolean setting.Comment: Submitted to Formal Methods in System Desig
Structural Refinement for the Modal nu-Calculus
We introduce a new notion of structural refinement, a sound abstraction of
logical implication, for the modal nu-calculus. Using new translations between
the modal nu-calculus and disjunctive modal transition systems, we show that
these two specification formalisms are structurally equivalent.
Using our translations, we also transfer the structural operations of
composition and quotient from disjunctive modal transition systems to the modal
nu-calculus. This shows that the modal nu-calculus supports composition and
decomposition of specifications.Comment: Accepted at ICTAC 201
Quantitative Modal Transition Systems
International audienceThis extended abstract offers a brief survey presentation of the specification formalism of modal transition systems and its recent extensions to the quantitative setting of timed as well as stochastic systems. Some applications will also be briefly mentioned
A Linear-Time Branching-Time Spectrum for Behavioral Specification Theories
We propose behavioral specification theories for most equivalences in the
linear-time--branching-time spectrum. Almost all previous work on specification
theories focuses on bisimilarity, but there is a clear interest in
specification theories for other preorders and equivalences. We show that
specification theories for preorders cannot exist and develop a general scheme
which allows us to define behavioral specification theories, based on
disjunctive modal transition systems, for most equivalences in the
linear-time--branching-time spectrum
General quantitative specification theories with modal transition systems
International audienceThis paper proposes a new theory of quantitative specifications. It generalizes the notions of step-wise refinement and compositional design operations from the Boolean to an arbitrary quantitative setting. Using a great number of examples, it is shown that this general approach permits to unify many interesting quantitative approaches to system design
Tree Regular Model Checking for Lattice-Based Automata
Tree Regular Model Checking (TRMC) is the name of a family of techniques for
analyzing infinite-state systems in which states are represented by terms, and
sets of states by Tree Automata (TA). The central problem in TRMC is to decide
whether a set of bad states is reachable. The problem of computing a TA
representing (an over- approximation of) the set of reachable states is
undecidable, but efficient solutions based on completion or iteration of tree
transducers exist. Unfortunately, the TRMC framework is unable to efficiently
capture both the complex structure of a system and of some of its features. As
an example, for JAVA programs, the structure of a term is mainly exploited to
capture the structure of a state of the system. On the counter part, integers
of the java programs have to be encoded with Peano numbers, which means that
any algebraic operation is potentially represented by thousands of applications
of rewriting rules. In this paper, we propose Lattice Tree Automata (LTAs), an
extended version of tree automata whose leaves are equipped with lattices. LTAs
allow us to represent possibly infinite sets of interpreted terms. Such terms
are capable to represent complex domains and related operations in an efficient
manner. We also extend classical Boolean operations to LTAs. Finally, as a
major contribution, we introduce a new completion-based algorithm for computing
the possibly infinite set of reachable interpreted terms in a finite amount of
time.Comment: Technical repor
10031 Abstracts Collection -- Quantitative Models: Expressiveness and Analysis
From Jan 18 to Jan 22, 2010, the Dagstuhl Seminar 10031 ``Quantitative Models: Expressiveness and Analysis \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available
Moving from Specifications to Contracts in Component-Based Design
Abstract. Program properties that are automatically inferred by static analysis tools are generally not considered to be completely trustworthy, unless the tool implementation or the results are formally verified. Here we focus on the formal verification of resource guarantees inferred by automatic cost analysis. Resource guarantees ensure that programs run within the indicated amount of resources which may refer to memory consumption, to number of instructions executed, etc. In previous work we studied formal verification of inferred resource guarantees that depend only on integer data. In realistic programs, however, resource consumption is often bounded by the size of heap-allocated data structures. Bounding their size requires to perform a number of structural heap analyses. The contributions of this paper are (i) to identify what exactly needs to be verified to guarantee sound analysis of heap manipulating programs, (ii) to provide a suitable extension of the program logic used for verification to handle structural heap properties in the context of resource guarantees, and (iii) to improve the underlying theorem prover so that proof obligations can be automatically discharged.