Requirements Formulation: Document Management vs Requirements Formulation: Document Management vs. Model Based System Engineering Clifford Levine April 24, 2017

Moving from document-centric to model-centric Document Management Past Specifications Interface requirements System design Analysis & Trade-off Test plans Future Moving from document-centric to model-centric

Document Based Engineering Requirements Management Behavioral Analysis Architecture Synthesis Verification Requirements Database Behavior Database Physical Architecture Database Verification Database Drawing Packages Spreadsheets Simulation Packages Word Processors Spreadsheets Drawing Packages Spreadsheets Testing Packages Spreadsheets Stovepiped efforts utilizing independent representations hides context, requires extraordinary data management, and complicates the SE effort

Model Based Systems Engineering Behavior Domain Source Requirements Domain Originating requirements trace to behavior Data c verified by Behavior is allocated to physical components V&V Domain Architecture Domain Data MODEL Data Utilizing a layered approach to progressively clarify and elaborate all four domains concurrently ensures consistency and completeness verified by verified by Originating requirements trace to physical components Vitech Corporation

MBSE Activities Timeline – Top Down 0. Define Need & System Concept 1. Capture & Analyze Orig. Requirements Can be restructured for middle out and reverse engineering projects. 2. Define System Boundary 3. Capture Originating Architecture Constraints 4. Derive System Threads 5. Derive Integrated System Behavior 6. Derive Component Hierarchy SCHEDULE 7. Allocate Behavior to Components 8. Define Internal Interfaces 9. Select Design 10. Perform Effectiveness & Feasibility Analyses 11. Define Resources, Error Detection, & Recovery Behavior 12. Develop Validation Requirements/Validation Plans 13. Generate Documentation and Specifications

Requirements (Sources) CONOP Potential Source Documents Vitech Corporation

Capturing Operational Concepts Shared vision of stakeholders Mission requirement(s) Collection of scenarios involving external systems Vitech Corporation

Requirements: Traceability CONOP Sources Model Tool Vitech Corporation

Layered Approach Level Of Detail LEVEL 1 LEVEL 2 LEVEL n REQ BEH Dgn V&V ARCH Source Documents Docs Level Of Detail LEVEL 1 REQ BEH ARCH DgnV&V Docs Docs LEVEL 2 REQ BEH ARCH Dgn V&V Docs Docs LEVEL n Must complete a layer before moving to the next layer (completeness) Cannot iterate back more than one layer (convergence) Vitech Corporation MBSE - CORE 8

View Generators Using a Common Repository Guarantee Consistent Views A graphical view is defined by features and a format The features are in the repository The format for each view type is defined in the view generator View generator contains format rules for each selected view type System Design Repository: Features of Elements & Control/Connection Constructs Vitech Corporation MBSE - CORE 8

Automated Documentation Generation System Design Repository Provided from the engineering database (from the start) Uses scripts to generate document files in RTF, HTML, & ASCII format; you publish in your word processor (e.g., Microsoft Word) Captures any internal graphic in WMF, JPEG, PNG, & SVG format Prints to any device if driver available, (e.g., laser, Postscript, plotter) *We will step you through two ways to generate documentation. Generic table output. Works great for Risk meetings. Customers and managers find this format easy to understand. Then we will generate an SDD (system description document) Vitech Corporation MBSE - CORE 8

MBSE: Restoring Analytical Rigor, Efficiency, and Effectiveness PowerPoint Engineering (Common Practice) Model-Based SE (Improved Practice) Independent drawings Consistent views Static diagrams Executable behavior Data storage Linked repository Stored views Dynamic view generation Ad hoc process (inconsistent results) Repeatable process (consistent results) Manual change propagation across all affected products (by the systems engineer) Automatic change propagation across all current and future products (by the engineering environment)

Thank You! For More Information Vitech Website http://www.vitechcorp.com/ Community http://community.vitechcorp.com/home/ Presenter zscott@vitechcorp.com We invite your comments and questions on the Community website at http://community.vitechcorp.com/forum/