Ken Pierce

Hugo Daniel Macedo, Casper Thule, Ken Pierce

This volume contains the papers presented at the 19th International Overture Workshop, which was held in an hybrid format: online and physically at Aarhus, Denmark on 22th October 2021. This event was the latest in a series of workshops around the Vienna Development Method (VDM), the open-source project Overture, and related tools and formalisms. VDM is one of the longest established formal methods for systems development. A lively community of researchers and practitioners has grown up in academia and industry around the modelling languages (VDM-SL, VDM++, VDM-RT, CML) and tools (VDMTools, Overture, VDM VSCode extension, Crescendo, Symphony, the INTO-CPS chain, and ViennaTalk). Together, these provide a platform for work on modelling and analysis technology that includes static and dynamic analysis, test generation, execution support, and model checking. This workshop provided updates on the emerging technology of VDM/Overture, including collaboration infrastructure, collaborative modelling and co-simulation for Cyber-Physical Systems.

Anirban Bhattacharyya, Andrey Mokhov, Ken Pierce

This paper uses a case study to evaluate empirically three formalisms of different kinds for their suitability for the modelling and analysis of dynamic reconfiguration of dependable systems. The requirements on an ideal formalism for dynamic software reconfiguration are defined. The reconfiguration of an office workflow for order processing is described, and the requirements on the reconfiguration of the workflow are defined. The workflow is modelled using the Vienna Development Method ($\mathrm{VDM}$), conditional partial order graphs ($\mathrm{CPOGs}$), and the basic Calculus of Communicating Systems for dynamic process reconfiguration (basic $\mathrm{CCS^{dp}}$), and verification of the reconfiguration requirements is attempted using the models. The formalisms are evaluated according to their ability to model the reconfiguration of the workflow, to verify the requirements on the workflow's reconfiguration, and to meet the requirements on an ideal formalism.

Anirban Bhattacharyya, Andrey Mokhov, Ken Pierce et al.

Three formalisms of different kinds - VDM, Maude, and basic CCSdp - are evaluated for their suitability for the modelling and verification of dynamic software reconfiguration using as a case study the dynamic reconfiguration of a simple office workflow for order processing. The research is ongoing, and initial results are reported.