On Modelling and Analysis of Dynamic Reconfiguration of Dependable Real-Time Systems

This paper motivates the need for a formalism for the modelling and analysis of dynamic reconfiguration of dependable real-time systems. We present requirements that the formalism must meet, and use these to evaluate well established formalisms and two process algebras that we have been developing, namely, Webpi and CCSdp. A simple case study is developed to illustrate the modelling power of these two formalisms. The paper shows how Webpi and CCSdp represent a significant step forward in modelling adaptive and dependable real-time systems.Comment: Presented and published at DEPEND 201

A Forward Reachability Algorithm for Bounded Timed-Arc Petri Nets

Timed-arc Petri nets (TAPN) are a well-known time extension of the Petri net model and several translations to networks of timed automata have been proposed for this model. We present a direct, DBM-based algorithm for forward reachability analysis of bounded TAPNs extended with transport arcs, inhibitor arcs and age invariants. We also give a complete proof of its correctness, including reduction techniques based on symmetries and extrapolation. Finally, we augment the algorithm with a novel state-space reduction technique introducing a monotonic ordering on markings and prove its soundness even in the presence of monotonicity-breaking features like age invariants and inhibitor arcs. We implement the algorithm within the model-checker TAPAAL and the experimental results document an encouraging performance compared to verification approaches that translate TAPN models to UPPAAL timed automata.Comment: In Proceedings SSV 2012, arXiv:1211.587

A technique for detecting wait-notify deadlocks in Java

Deadlock analysis of object-oriented programs that dynamically create threads and objects is complex, because these programs may have an infinite number of states. In this thesis, I analyze the correctness of wait - notify patterns (e.g. deadlock freedom) by using a newly introduced technique that consists in an analysis model that is a basic concurrent language with a formal semantic. I detect deadlocks by associating a Petri Net graph to each process of the input program. This model allows to check if a deadlock occur by analysing the reachability tree. The technique presented is a basic step of a more complex and complete project, since in my work I only consider programs with one object

A unifying Petri net model of non-interference and non-deducibility information flow security

In this paper we introduce FIFO Information Flow Nets (FIFN) as a model for describing information flow security properties. The FIFN is based on Petri nets and has been derived from the work described in [Var89], [Var90] and [Rou86]. Using this new model, we present the information flow security properties Non-Interference between Places (which corresponds to Non-Interference) and Non-Deducibility on Views (which corresponds to Non-Deducibility on Inputs). Then we consider a very general composition operation and show that neither Non-Interference on Places nor Non-Deducibility on Views is preserved under this composition operation. This leads us to a new definition of information flow security referred to as the Feedback Non-Deducibility on Views. We then show that this definition is preserved under the composition operation. This leads us to a new definition of information flow security referred to as the Feedback Non-Deducibility on Views. We then show that this definition is preserved under the composition operation. We then show some similarities between this property and the notion of Non-Deducibility on Strategies

Modeling the fraud-like investment founds by Petri nets

In this paper we model the fraud-like investment founds using place-transition Petri nets. We will also classify the business using regression line in order to find the possible fraud-like investment founds. In these regression lines we compute analytical the mark of a place in function of some other elements of the Petri net, and next we express this value in function of the same elements using regression. From the identity of the coefficients we find a ratio between two weights of arcs. We make also a program where the marks and transitions are implemented as classes for Petri nets, and, using the heritage mechanism we extend the Petri net to Petri net with priorities.Petri nets, fraud-like investment founds, objects programming.

A bibliography on formal methods for system specification, design and validation

Literature on the specification, design, verification, testing, and evaluation of avionics systems was surveyed, providing 655 citations. Journal papers, conference papers, and technical reports are included. Manual and computer-based methods were employed. Keywords used in the online search are listed

Creating Responsive Information Systems with the Help of SSADM

In this paper, a program for a research is outlined. Firstly, the concept of responsive information systems is defined and then the notion of the capacity planning and software performance engineering is clarified. Secondly, the purpose of the proposed methodology of capacity planning, the interface to information systems analysis and development methodologies (SSADM), the advantage of knowledge-based approach is discussed. The interfaces to CASE tools more precisely to data dictionaries or repositories (IRDS) are examined in the context of a certain systems analysis and design methodology (e.g. SSADM)