2,250 research outputs found
On the Distributability of Mobile Ambients
Modern society is dependent on distributed software systems and to verify
them different modelling languages such as mobile ambients were developed. To
analyse the quality of mobile ambients as a good foundational model for
distributed computation, we analyse the level of synchronisation between
distributed components that they can express. Therefore, we rely on earlier
established synchronisation patterns. It turns out that mobile ambients are not
fully distributed, because they can express enough synchronisation to express a
synchronisation pattern called M. However, they can express strictly less
synchronisation than the standard pi-calculus. For this reason, we can show
that there is no good and distributability-preserving encoding from the
standard pi-calculus into mobile ambients and also no such encoding from mobile
ambients into the join-calculus, i.e., the expressive power of mobile ambients
is in between these languages. Finally, we discuss how these results can be
used to obtain a fully distributed variant of mobile ambients.Comment: In Proceedings EXPRESS/SOS 2018, arXiv:1808.08071. Conference version
of arXiv:1808.0159
Functorial Semantics for Petri Nets under the Individual Token Philosophy
Although the algebraic semantics of place/transition Petri nets under the collective token philosophy has been fully explained in terms of (strictly) symmetric (strict) monoidal categories, the analogous construction under the individual token philosophy is not completely satisfactory because it lacks universality and also functoriality. We introduce the notion of pre-net to recover these aspects, obtaining a fully satisfactory categorical treatment centered on the notion of adjunction. This allows us to present a purely logical description of net behaviours under the individual token philosophy in terms of theories and theory morphisms in partial membership equational logic, yielding a complete match with the theory developed by the authors for the collective token view of net
Automating the transformation-based analysis of visual languages
The final publication is available at Springer via http://dx.doi.org/10.1007/s00165-009-0114-yWe present a novel approach for the automatic generation of model-to-model transformations given a description of the operational semantics of the source language in the form of graph transformation rules. The approach is geared to the generation of transformations from Domain-Specific Visual Languages (DSVLs) into semantic domains with an explicit notion of transition, like for example Petri nets. The generated transformation is expressed in the form of operational triple graph grammar rules that transform the static information (initial model) and the dynamics (source rules and their execution control structure). We illustrate these techniques with a DSVL in the domain of production systems, for which we generate a transformation into Petri nets. We also tackle the description of timing aspects in graph transformation rules, and its analysis through their automatic translation into Time Petri netsWork sponsored by the Spanish Ministry of Science and Innovation, project METEORIC (TIN2008-02081/TIN) and by the Canadian Natural Sciences and Engineering Research Council (NSERC)
A Compositional Approach for Schedulability Analysis of Distributed Avionics Systems
This work presents a compositional approach for schedulability analysis of
Distributed Integrated Modular Avionics (DIMA) systems that consist of
spatially distributed ARINC-653 modules connected by a unified AFDX network. We
model a DIMA system as a set of stopwatch automata in UPPAAL to verify its
schedulability by model checking. However, direct model checking is infeasible
due to the large state space. Therefore, we introduce the compositional
analysis that checks each partition including its communication environment
individually. Based on a notion of message interfaces, a number of message
sender automata are built to model the environment for a partition. We define a
timed selection simulation relation, which supports the construction of
composite message interfaces. By using assume-guarantee reasoning, we ensure
that each task meets the deadline and that communication constraints are also
fulfilled globally. The approach is applied to the analysis of a concrete DIMA
system.Comment: In Proceedings MeTRiD 2018, arXiv:1806.09330. arXiv admin note: text
overlap with arXiv:1803.1105
Modelling and validating the multi-agent system behaviour for a washing machine production line
This paper describes the formal modelling and validation of the behaviour of a multi-agent system that integrates the production and quality control processes in a washing machine production line. The modelling, analysis and validation process uses the Petri nets formalism that provides a rigorous and formal language based on its powerful mathematical foundation, supporting the complete verification of the system correctness during the design phase and before to proceed to the deployment phase. The behaviour models of each agent belonging to the system architecture are edited, analysed and simulated in the PnDK framework
Petri net model decomposition - a model based approach supporting distributed execution
Dissertação apresentada para obtenção do Grau de Doutor em Engenharia Electrotécnica, Especialidade de Sistemas Digitais, pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaModel-based systems development has contributed to reducing the enormous
difference between the continuous increase of systems complexity and the improvement of methods and methodologies available to support systems development.
The choice of the modeling formalism is an important factor for success-fully increasing productivity. Petri nets proved to be a suitable candidate for being chosen as a system specification language due to their natural support of modeling processes with concurrency, synchronization and resource sharing, as well as the mechanisms of composition and decomposition. Also
having a formal representation reinforces the choice, given that the use of
verification tools is fundamental for complex systems development.
This work proposes a method for partitioning Petri net models into concurrent sub-models, supporting their distributed implementation. The IOPT class (Input-Output Place Transition) is used as a reference class. It is extended by directed synchronous communication channels, enabling the com-
munication between the generated sub-models. Three rules are proposed to perform the partition, and restrictions of the proposed partition method are identified.
It is possible to directly compose models which result from the partitioning operation, through an operation of model addition. This allows the re-use of previously obtained models, as well as the easy modification of the intended system functionalities.
The algorithms associated with the implementation of the partition operation are presented, as well as its rules and other procedures. The proposed methods are validated through several case studies emphasizing control components of automation systems
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