Performing multi-viewpoint analysis : Thales case-study

From now, on this blog, my posts mainly described case-studies where model-driven engineering (MDE) has been used to produce code or modernize existing software systems.

Another domain where MDE is widely used is System Engineering. In this domain, Thales has acquired a strong experience with the Arcadia approach.

Arcadia is a model-based architecture engineering approach which has been tooled up in Eclipse with Melody Advance, a generic workbench developped  by Thales Engineering & Process Management with the assistance of Obeo.

Based on EMF and GMF, Melody Advance allows other Thales entities to create their own modeling tools. These modeling tools are declared with a dedicated DSL which is interpreted to dynamically provide the corresponding GMF modeling editors coming with ergonomic facilities and supporting large models.

Arcadia has been presented at MD Day 2011 by Jean-Luc Voirin, the System and Software Engineering Director of Research & Technology at Thales Aerospace & Mission Systems Division.

This approach has several objectives:

• To perform early validation of key architectural aspects to decrease the rework in design and production
• To improve the quality of architecture by taking better descisions regarding complex but necessary architectural trade-off
• To capitalize on both product definition and know-how by supporting negotiation and compromise between stakeholders

For Arcadia, Thales has integrated and extended several standards such as AADL, DoDAF, NAF, UML or SysML and added specific viewpoints to support:

• Operational analysis
• Functional analysis
• Logical architecture
• Physical architecture
• Non functional constraints
• Non functional trade-off
• Transition to software or hardware

Arcadia tooling provides several editors for these viewpoints and allows the system architects to graphically design and analyze a system.

System architects can evaluate their candidate architectures againts industrial constraints (cost & schedule, performance, safety, maintenability, product policy, etc). For each kind of constraint, layers can be applied on diagrams to graphicaly highlight the violated constraints.

Thanks to Melody Advance technology, this tool is easily customizable: Thales can define its own graphical representations and validation rules.

Initially developped to target signal processing, data processing and information systems, Thales detected much larger fields where Arcadia could be used such as electrical power systems or thermal systems.

For example, it can be used to work on several interleaved multi-physics models of a new airplane:

• a Power Model describing electrical generators, loads, converters, etc
• a Thermal model describing turbines, compressors, valves, etc
• a Command & Control model describing interfacing units, computing unit, data, etc

Specific viewpoints on these models can help the enginers to evaluate the solution architecture and detect problems before the IVVQ (Integration, Verification, Validation, Qualification) phase :

• power and thermal performance depending on flight phase consumption
• redundancy rules
• failure scenarios and propagation
• reconfiguration issues
• early identification of spatial arrangement constraints impacting the architecture
• etc

For Jean-Luc Voirin, one of the main benefit of this approach is to avoid exhaustive modelling. With the multi-viewpoint tooling, the architects can adjust modelling effort on major engineering issues.

The slides of the talk given by Jean-Luc Voirin can be found on Obeo Network (registration required).