1. Model-driven Architecture building
for constrained Systems
Jean-Luc Voirin
THALES
1

2. From Requirements allocation to Architecture
Mastering
Operational
Need Non-
Requirements Reqs functional
Functional Constraints
Need
Architecture building & Justification
« Requirement to Box
allocation »
Architecture Trade-
off
latediscovery of Early validation of the Architecture
design issues Mastering and optimisation of
during IVVQ product & IVVQ

3. ARCADIA Method
DoDAF, NAF
IEEE STD 1471 ARCADIA
A model-based Architecture
engineering approach Operational
Analysis
Non-
functional
Starts from standards Constraints
Functional
Analysis
Integrates & enriches them
Extensions
to a much wider scope
Logical
Architecture
Adds brand new Non-
multi-viewpoint functional
non-functional analysis Physical Viewpoints
Architecture Trade-off
thus allowing architecture
collaborative validation EPBS
& interoperability Transition to sub-system,SW,HW
through standards
AADL
SysML,
3
UML2

4. Method Steps: formalising & sharing Need & Solution
Operational Requirements
Analysis User Need
Engineering
Model What the users of the system need
to accomplish documents:
SSS, IRS,
System System Need OCD, …
Functional & NF Need
Model What the system has to accomplish
for the Users
Notional Solution
Logical Architecture
Model How the system will work so as to
fulfil expectations
Engineering
documents:
SSDD, ICD,
Final Solution PIDS, SRS,
Physical Architecture …
Model How the system will be developed
& built
Product Breakdown
Sub-contractors input

5. Summary of ARCADIA principles & capability
Industrial Constraints
Cost & Schedule Interfaces
Performance
Functional
Operational
Analysis Product Policy
User need Safety
Maintainability
Industrial
Etc…
Stakes
Validated solution
architecture
Candidate
Architectures
-Justified
Automatic Analysis - Shared
-Capitalised
5

6. Sample Example (bird eye): signal, data & info
processing Data & Interface Analysis
Operational
Analysis Functional Analysis
Modelling allows checking
solution against Need
Logical & Physical Architectures Including non-functional
constraints

7. Early Validation: How to check Solution Architecture
Perform a multi-viewpoint trade-off Analysis
 Safety  Performance  Product line  weight
 Security  Interfaces  Integration/V/V  Cost…
Product Line Architect
Customers Managers Requirement
Managers
Shared
Architects
Architecture Models
Logistics
Engineers
Specialty
Functions
Safety engineering:
Safety, Performance,
IVVQ
Performance safety, perf,
interface… Engineers SW/HW
Designers Manager Others…
Interfaces interface, …
& Developpers
Security
IVVQ, Product Line, Cost…
ViewPoints
Product Line
Manager etc… Evaluation Rules
Sub-
Solution
Architecture Components
contractors

8. Performance non-functional Viewpoint Operational
Analysis Non-
functional
Functional Constraints
Extensions
Analysis
Logical
Architecture Non-
functional
Physical Viewpoints
1° Automatic analysis:Architecture Trade-off
EPBS
-CPU overloaded Transition to sub-,SW,HW
-Bus overloaded
-Latency in excess
2° Causal analysis
-Tool locates problems
-Quantitative analysis
3° Architecture
improvement:
-Lighter protocols
-Higher bandwidth
-Hardware processing
8

9. Safety non-functional Viewpoint Operational
Analysis Non-
functional
Functional Constraints
Extensions
Analysis
Logical
Architecture Non-
functional
Physical Viewpoints
1° Automatic analysis: Architecture Trade-off
EPBS
-Rule: “No single source for
Transition to sub-,SW,HW
major failure condition”
-Not met for video
2° Causal analysis
-Tool locates problems
-Failure propagation algorithm
3° Architecture
improvement:
-Second redundant server
9

10. Multi-Viewpoints Trade-off Operational
Analysis Non-
functional
Functional Constraints
Extensions
Analysis
Logical
Non-
Confrontation rules for multi-viewpoints trade-off
Architecture
functional
Physical Viewpoints
Architecture Trade-off
EPBS
Transition to sub-,SW,HW
10

11. Field of application
Initially developped to target
signal processing, data processing,
information systems
Appears to be applicable to much larger field
e.g. electrical power systems
Thermal systems
…
MDDay 2011 11

12. Example: Three interleaved, multi-physics Models
Electrical Generators,
Loads, converters, bus bars…
Power Model
-Generation
Electrical power
-Distribution
Turbines, Compressors,
Thermal Model heat exchangers, valves…
-Conditioning
-Pressurisation
Thermal Power
-Equipments Cooling
Command & Control Model Interfacing &
(coming soon) computing units…
Data
12

13. Power / thermal Model dedicated Viewpoints
Power & Thermal performance
depending on flight phase consumption, incl. Overloaded components
detection based on power computation, linked to thermal Model
Safety / Integrity
incl. Failure containment, redundancy rules & analysis,
failure scenarios & propagation, monitoring efficiency, shielding…
Viewpoints
Reliability & Availability
incl. Reliability computing, reconfiguration issues, flight delay…
Solution
Architecture
Spatial (3D) arrangement
Early identification of spatial arrangement constraints impacting
the architecture
And also: Mass, Cost, Reliability…
13

14. Conclusion: Return of Experiment
Early validation of key architectural aspects
Less rework in design & production
Efficient decision making regarding complex but
necessary architectural trade-off
Improved quality of architecture
Support to negotiation and compromise between
stakeholders
Ability to capitalise both product definition and know-
how
14

15. Conclusion: Return of Experiment
Support to interoperation with Customers & Suppliers
Interoperability with and beyond Standards Support
Benefits and guidelines for foreign tools integration,
esp. simulation and specialty tools
Ability to adjust modelling effort:
scaled/focused on major engineering issues for return on
invest
Without exhaustive modelling
15

16. ARCADIA Support by Melody Advance Modeller
Melody Advance solves Weaknesses of COTS* or
OSS*:
ARCADIA Method support & guidance for modelling
• Method Steps, encyclopedia, rules, diagrams…
User-oriented Semantics
• Engineer concepts rather than abstract/profiled language
Support for « modelling in the large »
• Performance on large models, ergonomy, modelling aids…
Support for Viewpoint extensions, modelling & analysis
• Model extensions, diagrams extensions, viewpoint
maangement…
« semantic » Import/export capabilities (excel, SysML,
AF, …)
Yet ARCADIA is also deployed using other tools * COTS: Commercial Off The Shelf
* OSS: Open Source Software
• Excel/Access, Rhapsody, System Architect/DoDAF…
• with reduced capabilities, however