Towards a methodology for modelling with Petri nets

Formal specifications remain difficult to write in general, due to both the complexity of the system to be developed, and the use of a formal language. In [CR03a], a method is proposed for specification development, with CASL, the Common Algebraic Specification Language, and CASL-LTL, an extension for dynamic systems specification, as target languages. However, this method could be used with quite a variety of modeling languages, as shown in this paper which is a first attempt to provide systematic guidelines for Petri net specification on the ground of the aforementioned specification method. It is shown how to express in terms of Petri nets the constituent features and the properties exhibited from the first specification approach. A model train specification from [BP00] is used as a running example

An Architecture Dynamic Modeling Language for Self-Healing Systems

AbstractAs modern software-based systems increase in complexity, recovery from malicious attacks and rectification of system faults become more difficult, labor-intensive, and error-prone. These factors have actuated research dealing with the concept of self-healing systems, which employ architectural models to monitor system behavior and use inputs obtaining therefore to adapt themselves to the run-time environment. Numerous architectural description languages (ADLs) have been developed, each providing complementary capabilities for architectural development and analysis. Unfortunately, few ADLs embrace dynamic change as a fundamental consideration and support a broad class of adaptive changes at the architectural level. The Architecture Dynamic Modeling Language (ADML) is being developed as a new formal language and/or conceptual model for representing dynamic software architectures. TheADML couple the static information provided by the system requirements and the dynamic knowledge provided by tactics, and offer a uniform way to represent and reason about both static and dynamic aspects of self-healing systems. Because the ADML is based on the Dynamic Description Logic DDL, architectural ontology entailment for the ADML languages can be reduced to knowledge base satisfiability in DDL

A Formal and Tool-Equipped Approach for the Integration of State Diagrams and Formal Datatypes

International audienceSeparation of concerns or aspects is a way to deal with the increasing complexity of systems. The separate design of models for different aspects also promotes a better reusability level. However, an important issue is then to define means to integrate them into a global model. We present a formal and tool-equipped approach for the integration of dynamic models (behaviors expressed using state diagrams) and static models (formal data types) with the benefit to share advantages of both: graphical user-friendly models for behaviors, formal and abstract models for data types. Integration is achieved in a generic way so that it can deal with both different static specification languages (algebraic specifications, Z, B) and different dynamic specification semantic

Dynamic Complexity of Formal Languages

The paper investigates the power of the dynamic complexity classes DynFO, DynQF and DynPROP over string languages. The latter two classes contain problems that can be maintained using quantifier-free first-order updates, with and without auxiliary functions, respectively. It is shown that the languages maintainable in DynPROP exactly are the regular languages, even when allowing arbitrary precomputation. This enables lower bounds for DynPROP and separates DynPROP from DynQF and DynFO. Further, it is shown that any context-free language can be maintained in DynFO and a number of specific context-free languages, for example all Dyck-languages, are maintainable in DynQF. Furthermore, the dynamic complexity of regular tree languages is investigated and some results concerning arbitrary structures are obtained: there exist first-order definable properties which are not maintainable in DynPROP. On the other hand any existential first-order property can be maintained in DynQF when allowing precomputation.Comment: Contains the material presenten at STACS 2009, extendes with proofs and examples which were omitted due lack of spac

Towards formal models and languages for verifiable Multi-Robot Systems

Incorrect operations of a Multi-Robot System (MRS) may not only lead to unsatisfactory results, but can also cause economic losses and threats to safety. These threats may not always be apparent, since they may arise as unforeseen consequences of the interactions between elements of the system. This call for tools and techniques that can help in providing guarantees about MRSs behaviour. We think that, whenever possible, these guarantees should be backed up by formal proofs to complement traditional approaches based on testing and simulation. We believe that tailored linguistic support to specify MRSs is a major step towards this goal. In particular, reducing the gap between typical features of an MRS and the level of abstraction of the linguistic primitives would simplify both the specification of these systems and the verification of their properties. In this work, we review different agent-oriented languages and their features; we then consider a selection of case studies of interest and implement them useing the surveyed languages. We also evaluate and compare effectiveness of the proposed solution, considering, in particular, easiness of expressing non-trivial behaviour.Comment: Changed formattin