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SysML Reference Model Definition. Model Based System Development in the Joint Strike Missile project Svein-Erik Søgård KDS/Missile Division. Agenda. Introduction Background Goals for modeling Challenges Model definition Principles Walktrough of process and reference model Summary
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SysML Reference Model Definition Model Based System Development in the Joint Strike Missile project Svein-Erik Søgård KDS/Missile Division
Agenda WORLD CLASS - through people, technology and dedication. Introduction • Background • Goals for modeling • Challenges Model definition • Principles • Walktrough of process and reference model Summary • Lessons learned
Background WORLD CLASS - through people, technology and dedication. Main motivation for MBSE in JSM • Lack of system and architecture level documentation in previous projects • Many documents and model fragments but not up to date, poor value for money (waste), not systematically organized). Very hard for • Maintainability • Introducing new developers • Doing analysis (e.g. safety) • Initiative from Management (LEAN thinking) as well as a JSM core team of developers that would do it better
Background WORLD CLASS - through people, technology and dedication. KDS Survey that concluded with SysML and MagicDraw™ modeling tool • Major player in MBSE • Simultaneously evaluated UML tool for SW modeling • smooth transition to SW development was important JSM project main focus so far on functional analysis & design, but also physical architecture is addressed MagicDraw™ is NOT «THE System Tool» • Used in conjunction with other tools • Information management • Linking other documentation rather than duplicating it
Goals WORLD CLASS - through people, technology and dedication. «Real» Model Based, • Not only drawings and model fragments • Consistent model with a set of well defined views System Model (SysML) characteristics • Complete functional description (concise, right abstraction level) focused on what the system shall do. Easy entry point to what the system shall do and how it works • Physical System Architecture that is precise and detailed about interfaces at different levels (How the system shall be constructed) • Specifications for component design (in other disciplines: SW, PLD electronics, mechanics) • Focus on maintainability (of the model and the product)
Challenges WORLD CLASS - through people, technology and dedication. Project size (JSM) is too large to be optimal • “How to do” established later than desirable • doing development and establishing how to model in parallell • Too few resources to follow up new teams Culture (document centric, different philosophy & terminology) • Commitment to the process and methodology • Commitment from engineers are even more important than commitment from management • developers tend to fall back to «their old methods» when they get pressed for time SysML is a complex language. Requires time to understand what to use and how to use it to make consistent models.
Reference Model Definition WORLD CLASS - through people, technology and dedication. Motivation: SysMLis a (too) complex language – we need to define which subset to use and how Steps: • DefinedModelingProcess • Definedreferencemodel • Subset of SysML (elements and diagrams) • Definemetamodelofhowmodel elements arerelated • Model organization (views/perspectives) • Tools customization • Profile (extensionwith DSL) • Diagram Customization • Validationrules
Reference Model Definition WORLD CLASS - through people, technology and dedication. Basic Principles • Avoid redundancy and duplication of information • Be very clear about the different abstraction levels (hard!) • Shall not cover all details nor repeat or duplicate information from other tools (link in instead)
Reference Model Definition WORLD CLASS - through people, technology and dedication. Process modeled using SysML Activity Diagrams Walkthrough (HTML generated from MagicDraw™)
Summary WORLD CLASS - through people, technology and dedication. MUST make a standardization of modeling to make a maintainable model • Do systematic stakeholder analysis • Reference model, guidelines • Tools customization • Customized to process and modeling style • Suite of validation rules Build up a core team that is skilled before rolling it out • Use consultancy • Do peer modeling • Both SysML and tools experience required
Summary WORLD CLASS - through people, technology and dedication. If possible – select a small project (but not too small) and cover all phases/aspects before rolling it out in large scale Do not try to cover all aspects of system engineering/modeling from the start (eat the elephant piece by piece) Be aware on separating between “throw-away” models and maintainable models • «less is more»