1 Copyright © 2014 Atego. Patterns INCOSE MBSE WG – Simon A. Perry - Atego

2 Copyright © 2014 Atego. 1. Overview 1.What are patterns? 2.An approach to documenting patterns 3.Candidate patterns 4.Summary 5.References 6.Questions

3 Copyright © 2014 Atego. 1. What are patterns?  “A pattern describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice". -Christopher Alexander, ‘A Pattern Language’, 1977  Original ideas from (building) architecture but adopted by software engineering OO community -Made more widely known through “Gang of Four Book” (1995)  Ideas spread to analysis and data modelling through books by Fowler (1997) and Day (1996)  Now being adopted in the wider systems engineering community

4 Copyright © 2014 Atego. Architectural vs. Enabling Patterns  On the COMPASS project ( we use the terms architectural pattern and enabling pattern  Architectural patterns -Describe specific system architectures, in terms of both structure and behaviour, which address particular needs of the system  Enabling patterns -Specific constructs of modelling elements whose combination and subsequent use enables a number of systems engineering applications -E.g. one used for the definition of interfaces or one used to ensure traceability throughout a model of a system  See COMPASS Deliverable D22.3 ‘Report on Modelling Patterns for SoS Architectures’ -Available from

5 Copyright © 2014 Atego. 2. An approach to documenting patterns  When defining patterns it is important to use a consistent model-based approach  One such approach is based on around the ideas of ontology, viewpoints and framework  Ontology -Define concepts and relationships between them  Viewpoints and Framework -Define viewpoints organised into a framework -Viewpoints can only use concepts from the ontology  Originally developed by Brownsword, Holt and Perry (2011) -Further refined by Holt & Perry (2013) (the Framework for Architectural Frameworks – FAF) -Adopted in the COMPASS project (FAF adopted into COMPASS as the CAFF)

6 Copyright © 2014 Atego. The COMPASS Architectural Framework Framework (CAFF)  The CAFF was initially developed to improve the definition of Architectural Frameworks (AFs) -Applicable to the definition of patterns  Consists of: -An ontology -Six viewpoints -Supporting processes  Described in COMPASS Deliverable D21.2 ‘Initial Report on Guidelines for Architectural Level SoS Modelling’ -Available from

7 Copyright © 2014 Atego. The CAFF Ontology

8 Copyright © 2014 Atego. The CAFF Viewpoints  AF Context Viewpoint (AFCV) -Defines the context for the AF -Represents the AF concerns in context, establishing why the AF is needed  Ontology Definition Viewpoint (ODV) -Defines the ontology for the AF -Derived from the AF Context Viewpoint & and defines concepts that can appear on a Viewpoint  Viewpoint Relationships Viewpoint (VRV) -Shows the relationships between the Viewpoints that make up an AF -Groups them into perspectives. It is derived from the Ontology Definition Viewpoint

9 Copyright © 2014 Atego. The CAFF Viewpoints continued  Viewpoint Context Viewpoint (VCV) -Defines the context for a particular Viewpoint -Represents the Viewpoint concerns in context for a particular Viewpoint, establishing why the Viewpoint is needed. It is derived from the AF Context Viewpoint  Viewpoint Definition Viewpoint (VDV) -Defines a particular Viewpoint -Shows the Viewpoint Elements (and hence the Ontology Elements) that appear on the Viewpoint  Rules Definition Viewpoint (RDV) -Defines the various rules that constrain the AF

10 Copyright © 2014 Atego. The CAFF Viewpoints

11 Copyright © 2014 Atego. The CAFF Viewpoints – an example of use for the Traceability Pattern

12 Copyright © 2014 Atego. The CAFF Viewpoints – an example of use for the Traceability Pattern

13 Copyright © 2014 Atego. The CAFF Viewpoints – an example of use for the Traceability Pattern

14 Copyright © 2014 Atego. The CAFF Viewpoints – an example of use for the Traceability Pattern

15 Copyright © 2014 Atego. The CAFF Viewpoints – an example of use for the Traceability Pattern

16 Copyright © 2014 Atego. The CAFF Viewpoints – an example of use for the Traceability Pattern

17 Copyright © 2014 Atego. 3. Candidate patterns  Defined by Atego -Interface Definition -Traceability -Testing -Life Cycle -Epoch  In development by Atego -Connection -Context -Description  What others are of interest? -Patterns workshop next session

18 Copyright © 2014 Atego. 4. Summary  Patterns are now seen as a useful and powerful tool in model-based systems engineering  Patterns (and their extensions, Architectural Frameworks) need to be described in a consistent fashion  Work has been undertaken (and is continuing) on the COMPASS project in the collection and definition of appropriate architectural and enabling patterns  The COMPASS Architectural Framework Framework, though initially developed to help in the consistent definition of AFs can also be used in the definition of patterns

19 Copyright © 2014 Atego. 5. References  Alexander, C.S., Ishikawa, M., Silverstein, M., Jacobson, M., Fiksdahl- Ling, I. & Angel, S. ‘A Pattern Language’. New York: Oxford University Press; 1977  Gamma, E., Helm, R., Johnson, R. & Vlissides, J. ‘Design Patterns – Elements of Reusable Object Oriented Software.’ Boston, MA: Addison- Wesley; 1995  Hay, D. ‘Data Model Patterns: Conventions of Thought’. New York: Dorset House; 1996  Fowler, M. ‘Analysis Patterns: Reusable Object Models’. Boston, MA: Addison-Wesley; 1997

20 Copyright © 2014 Atego. References continued  COMPASS. ‘D22.3 – Report on Modelling Patterns for SoS Architectures’; COMPASS Project; 2013  COMPASS. ‘D21.2 – Initial Report on Guidelines for Architectural Level SoS Modelling’. COMPASS Project; 2013  Holt, J, Perry, S & Brownsword, M. ‘Model-Based Requirements Engineering’. IET Publishing, 2011  Holt, J & Perry, S. ‘SysML for Systems Engineering; 2 nd Edition: A model- based approach’. London: IET Publishing; 2013

21 Copyright © 2014 Atego. 6. Questions