4,590 research outputs found
A Constrained Object Model for Configuration Based Workflow Composition
Automatic or assisted workflow composition is a field of intense research for
applications to the world wide web or to business process modeling. Workflow
composition is traditionally addressed in various ways, generally via theorem
proving techniques. Recent research observed that building a composite workflow
bears strong relationships with finite model search, and that some workflow
languages can be defined as constrained object metamodels . This lead to
consider the viability of applying configuration techniques to this problem,
which was proven feasible. Constrained based configuration expects a
constrained object model as input. The purpose of this document is to formally
specify the constrained object model involved in ongoing experiments and
research using the Z specification language.Comment: This is an extended version of the article published at BPM'05, Third
International Conference on Business Process Management, Nancy Franc
Requirements modelling and formal analysis using graph operations
The increasing complexity of enterprise systems requires a more advanced
analysis of the representation of services expected than is currently possible.
Consequently, the specification stage, which could be facilitated by formal
verification, becomes very important to the system life-cycle. This paper presents
a formal modelling approach, which may be used in order to better represent
the reality of the system and to verify the awaited or existing systemās properties,
taking into account the environmental characteristics. For that, we firstly propose
a formalization process based upon properties specification, and secondly we
use Conceptual Graphs operations to develop reasoning mechanisms of verifying
requirements statements. The graphic visualization of these reasoning enables us
to correctly capture the system specifications by making it easier to determine if
desired properties hold. It is applied to the field of Enterprise modelling
Specifying Reusable Components
Reusable software components need expressive specifications. This paper
outlines a rigorous foundation to model-based contracts, a method to equip
classes with strong contracts that support accurate design, implementation, and
formal verification of reusable components. Model-based contracts
conservatively extend the classic Design by Contract with a notion of model,
which underpins the precise definitions of such concepts as abstract
equivalence and specification completeness. Experiments applying model-based
contracts to libraries of data structures suggest that the method enables
accurate specification of practical software
A robust semantics hides fewer errors
In this paper we explore how formal models are interpreted and to what degree meaning is captured in the formal semantics and to what degree it remains in the informal interpretation of the semantics. By applying a robust approach to the definition of refinement and semantics, favoured by the event-based community, to state-based theory we are able to move some aspects from the informal interpretation into the formal semantics
A Reasoner for Calendric and Temporal Data
Calendric and temporal data are omnipresent in countless
Web and Semantic Web applications and Web services. Calendric and
temporal data are probably more than any other data a subject to
interpretation, in almost any case depending on some cultural, legal,
professional, and/or locational context. On the current Web, calendric
and temporal data can hardly be interpreted by computers. This article
contributes to the Semantic Web, an endeavor aiming at enhancing
the current Web with well-defined meaning and to enable computers to
meaningfully process data. The contribution is a reasoner for calendric
and temporal data. This reasoner is part of CaTTS, a type language for
calendar definitions. The reasoner is based on a \theory reasoning" approach
using constraint solving techniques. This reasoner complements
general purpose \axiomatic reasoning" approaches for the Semantic Web
as widely used with ontology languages like OWL or RDF
Fifty years of Hoare's Logic
We present a history of Hoare's logic.Comment: 79 pages. To appear in Formal Aspects of Computin
Z2SAL: a translation-based model checker for Z
Despite being widely known and accepted in industry, the Z formal specification language has not so far been well supported by automated verification tools, mostly because of the challenges in handling the abstraction of the language. In this paper we discuss a novel approach to building a model-checker for Z, which involves implementing a translation from Z into SAL, the input language for the Symbolic Analysis Laboratory, a toolset which includes a number of model-checkers and a simulator. The Z2SAL translation deals with a number of important issues, including: mapping unbounded, abstract specifications into bounded, finite models amenable to a BDD-based symbolic checker; converting a non-constructive and piecemeal style of functional specification into a deterministic, automaton-based style of specification; and supporting the rich set-based vocabulary of the Z mathematical toolkit. This paper discusses progress made towards implementing as complete and faithful a translation as possible, while highlighting certain assumptions, respecting certain limitations and making use of available optimisations. The translation is illustrated throughout with examples; and a complete working example is presented, together with performance data
- ā¦