Representations and Models: SysML and Beyond David Long Vitech Corporation SEDC 20121

In the beginning, a basic set of views… 2SEDC 2012

Followed by evolution… 3SEDC 2012

And insights and influences from UML… 4SEDC 2012

Next the introduction of frameworks… 5SEDC 2012

And the SysML revolution! 6SEDC 2012

Complex Problems, Diverse Groups, and Clear Needs 7 Analysis, presentation, and argumentation SEDC 2012

What Is A View? 8 MODEL VIEW SEDC 2012

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Transitioning to an Integrated Toolbox of Fit-for-Purpose Views 10 Reprinted from DoDAF 2.0 SEDC 2012

Criteria for Diagram Choice Who is your audience? What do they want/need to see? What do you want/need to tell them? 11SEDC 2012

VIEWS DEPICT BEHAVIOR 12 Make Information Request Accept & Format RequestGet Product from Inventory Provide Product to Customer Accept Product SEDC 2012

An Integrated Picture of Behavioral Views What about audience? level of detail? 13 Concepts reflected Composition Control / Structure Triggering Data Flow Allocation SEDC 2012

Behavioral Views 14 DoDAF OV-1 Level of Detail: Low Audience: General Content: General context often with lightweight composition, triggering, and allocation Use: High-level contextual introduction to describe operational boundaries and align system vision FFBD Level of Detail: Low Audience: General, excluding software engineers Content: Specification of flow of control Use: Initial capture of threads and integrated behavior when focusing purely on control aspects Sequence Diagram Level of Detail: Medium Audience: General Content: Specification of sequence (but not control), allocation, and triggering Use: Initial capture of threads when focusing purely on triggering aspects; communication with software engineers SEDC 2012

Behavioral Views, cont. 15 N2 Diagram Level of Detail: Low Audience: General Content: Data flow with possible inclusion of allocation Use: Focused understanding of data flow and implied interfaces; clustering analysis IDEF0 Diagram Level of Detail: High Audience: Traditional SEs and process engineers Content: Data flow, triggering, and allocation Use: Analysis of data flow with diagnostics of inconsistencies across behavioral decomposition State Transition Diagram Level of Detail: Medium Audience: System and software engineers Content: System states and the corresponding transitions Use: Insight into the system by taking an orthogonal look at behavior SEDC 2012

Behavioral Views, cont. 16 Enhanced FFBD Level of Detail: High Audience: Not software engineers or SysML zealots Content: Composition, triggering, resourcing, and allocation Use: Full specification of system behavior; best at higher levels of decomposition (level 0, level 1, …) when dealing with broader audiences Activity Diagram Level of Detail: Highest Audience: System and software engineers Content: Composition, triggering, and allocation Use: Full specification of system behavior; best at lower levels of decomposition (design view) Simulation Timeline Level of Detail: Medium Audience: General Content: True performance aspects of specified behavior Use: Debugging system logic; analysis of performance characteristics SEDC 2012

VIEWS DEPICT COMPONENTS 17SEDC 2012

An Integrated Picture of Physical Views 18 PHYSICAL CHARACTERISTICS SPECTRUM More composition Less connectivity Less composition More connectivity Hierarchy Block Definition Internal Block Level 0 Level N Physical N2 Interface Block Physical Block Concepts Composition Connections Inheritance SEDC 2012

Physical Views 19 DoDAF SV-1 Level of Detail: Medium Audience: General Content: General context with lightweight composition and connectivity (logical and physical) Use: High-level contextual introduction to describe system boundaries and align system vision Physical Hierarchy Level of Detail: Low Audience: General Content: Multi-level specification of system composition Use: In-depth hierarchical presentation of parts list SEDC 2012

Physical Views, cont. 20 Block Definition Diagram (Classification) Level of Detail: High Audience: System and software engineers Content: System inheritance model Use: Detailed representation of any system inheritance and corresponding characteristics; software class diagram Level of Detail: High Audience: System/software engineers and subject matter experts (SMEs) Content: Physical composition often including block roles and characteristics Use: Detailed, multi-level design representation of system composition and corresponding physical characteristics Block Definition Diagram (Structure) SEDC 2012

Physical Views, cont. 21 Physical N2 Diagram Level of Detail: Low Audience: General Content: Single-level composition with corresponding logical (interface) or physical (link) connections Use: High-level identification of connections; clustering analysis Internal Block Diagram Level of Detail: High Audience: System/software engineers and SMEs Content: Specification of logical or physical connectivity often with ports, directionality, and corresponding data flows Use: Specification of logical or physical connections Interface Block and Physical Block Diagrams Level of Detail: Medium Audience: Not software engineers or SysML zealots Content: Composition with logical or physical connectivity Use: Specification of logical or physical connections; boundary definition; insight into external connections SEDC 2012

VIEWS DEPICT REQUIREMENTS 22SEDC 2012

Requirement Views 23 Level of Detail: Medium Audience: System/software engineers Content: Names, relationships, and descriptions Use: Limited use (a toy representation); context for limited set of requirements Requirements Diagram Hierarchy Diagram Level of Detail: Low Audience: General Content: Names and relationships Use: Multi-level decomposition and traceability of requirements Tables Level of Detail: High Audience: General Content: Requirement properties and relationships Use: Requirement lists; traceability matrices; verification matrices SEDC 2012

A Few Additional Representations 24 Parametric Diagram Level of Detail: High Audience: Systems engineers and SMEs Content: System parameter definition Use: Mathematical specification of key system parameters Use Case Diagram Level of Detail: Low Audience: General Content: Use cases and corresponding actors (components) Use: High-level tool to elicit requirements; bridge from requirements to system threads Spider Diagram Level of Detail: Low Audience: General Content: Object names and interrelationships Use: Contextual view of objects of interest with no implied meaning Dashboards Level of Detail: Low Audience: General Content: Fusion content Use: Single page focused illustration; often measurement / management SEDC 2012

25 A Consistent View of Views

Geospatial Library pbd Geospatial Library C.3 Customer Certification Authority C.1 Customers C.2 Collectors SYS.1.2 Workstation SYS.1.1 Command Center Geospatial Library Certification Request Link Certification Response Link Request Link Return Link Status Link Collector Product Link Command Link GL Internal Link

Customers Geospatial Library seq Thread 1- Product in Inventory

SEDC A Consistent View of Views

The Trap to Avoid Disjoint fit-for-purpose views can wreck our project on the rocky shores 32 Diagrams must be representational tools from the model, not a substitute for a model SEDC 2012