Maurice H. ter Beek

A state/event-based model-checking approach for the analysis of abstract system properties

We present the UMC framework for the formal analysis of concurrent systems specified by collections of UML state machines. The formal model of a system is given by a doubly labelled transition system, and the logic used to specify its properties is the state-based and event-based logic UCTL. UMC is an on-the-fly analysis framework which allows the user to interactively explore a UML model, to visualize abstract behavioural slices of it and to perform local model checking of UCTL formulae. An automotive scenario from the service-oriented computing (SOC) domain is used as case study to illustrate our approach.

Synchronizations in Team Automata for Groupware Systems

Team automata have been proposed in Ellis (1997) as a formal framework for modeling both the conceptual and the architectural level of groupware systems. Here we define team automata in a mathematically precise way in terms of component automata which synchronizeon certain executions of actions.At the conceptual level, our model serves as a formal framework in whichbasic groupware notions can be rigorously defined and studied.At the architectural level, team automata can be used as building blocksin the design of groupware systems.

An action/state-based model-checking approach for the analysis of communication protocols for service-oriented applications

In this paper we present an action/state-based logical frameworkfor the analysis and verification of complex systems, which relies onthe definition of doubly labelled transition systems. The defined temporallogic, called UCTL, combines the action paradigm--classically usedto describe systems using labelled transition systems--with predicatesthat are true over states--as captured when using Kripke structures assemantic model. An efficient model checker for UCTL has been realized,exploiting an on-the-fly algorithm. We then show how to use UCTL, andits model checker, in the design phase of an asynchronous extension of thecommunication protocol SOAP, called aSOAP. For this purpose, we describeaSOAP as a set of communicating UML state machines, for whicha semantics over doubly labelled transition systems has been provided.

A logical framework to deal with variability

We present a logical framework that is able to deal with variability in product family descriptions. The temporal logic MHML is based on the classical Hennessy-Milner logic with Until and we interpret it over Modal Transition Systems (MTSs). MTSs extend the classical notion of Labelled Transition Systems by distinguishing possible (may) and required (must) transitions: these two types of transitions are useful to describe variability in behavioural descriptions of product families. This leads to a novel deontic interpretation of the classical modal and temporal operators, which allows the expression of both constraints over the products of a family and constraints over their behaviour in a single logical framework. Finally, we sketch model-checking algorithms to verify MHML formulae as well as a way to derive correct products from a product family description.

VMC: A Tool for Product Variability Analysis

We present VMC, a tool for the modeling and analysis of variability in product lines. It accepts a product family specified as a modal transition system, possibly with additional variability constraints, after which it can automatically generate all the family’s valid products, visualize the family/products as modal/labeled transition systems, and efficiently model check properties expressed in an action- and state-based branching-time temporal logic over products and families alike.

Formal verification of an automotive scenario in service-oriented computing

We report on the successful application of academic experience with formal modelling and verification techniques to an automotive scenario from the service-oriented computing domain. The aim of this industrial case study is to verify a priori, thus before implementation, certain design issues. The specific scenario is a simplified version of one of possible new services for car drivers to be provided by the in-vehicle computers.

Combining declarative and procedural views in the specification and analysis of product families

We introduce the feature-oriented language FLan as a proof of concept for specifying both declarative aspects of product families, namely constraints on their features, and procedural aspects, namely feature configuration and run-time behaviour. FLan is inspired by the concurrent constraint programming paradigm. A store of constraints allows one to specify in a declarative way all common constraints on features, including inter-feature constraints. A standard yet rich set of process-algebraic operators allows one to specify in a procedural way the configuration and behaviour of products. There is a close interaction between both views: (i) the execution of a process is constrained by its store to forbid undesired configurations; (ii) a process can query a store to resolve design and behavioural choices; (iii) a process can update the store by adding new features. An implementation in the Maude framework allows for a variety of formal automated analyses of product families specified in FLan, ranging from consistency checking to model checking.

CMC-UMC: a framework for the verification of abstract service-oriented properties

CMC and UMC are two prototypical instantiations of a common logical verification framework for the analysis of functional properties of service-oriented systems. The service-oriented SocL logic is used to describe the required system properties. Computational models of the system can be built either using the COWS specification language or designing the system as a collection of interacting UML state machines, and an on-the-fly model checker can be used to verify the satisfaction of the requirements and possibly to generate counterexamples or witnesses for them. An automotive case study is used to illustrate the overall framework.

Using mCRL2 for the analysis of software product lines

We show how the formal specification language mCRL2 and its state-of-the-art toolset can be used successfully to model and analyze variability in software product lines. The mCRL2 toolset supports parametrized modeling, model reduction and quality assurance techniques like model checking. We present a proof-of-concept, which moreover illustrates the use of data in mCRL2 and also how to exploit its data language to manage feature attributes of software product lines and quantitative constraints between attributes and features.

A model-checking tool for families of services

We propose a model-checking tool for on-the-fly verification of properties expressed in a branching-time temporal logic based on a deontic interpretation of classical modal and temporal operators over modal transition systems. We apply this tool to the analysis of variability in behavioural descriptions of families of services.