IBM Software Group Agile ModelBased Systems Engineering a

® IBM Software Group Agile Model-Based Systems Engineering (a. MBSE) Bruce Powel Douglass, Ph. D. Chief Evangelist, Global Technology Ambassador IBM Rational Bruce. Douglass@us. ibm. com Twitter: @Bruce. Douglass Yahoo: tech. groups. yahoo. com/group/RT-UML/ IBM: www 01. ibm. com/software/rational/leadership/thought/Bruce. Douglass. html Innovation for a smarter planet © 2014 IBM Corporation

IBM Software Group | Rational software State of the Practice for Systems Development § Systems Engineering Environments in general 4 Are document-centric 4 Require huge investment in planning that doesn’t reflect actual project execution 4 Have difficulty adapting to change. 4 Require expensive and error-prone manual review and update processes. 4 Require long integration and validation cycles 4 Are difficult to maintain over the long haul § Additional standards constraints (eg DO-178 C, ARP 4761, ISO 26262, AUTOSAR, Do. DAF) add to the challenge 4 Tooling Selection 4 Dependability engineering § Safety § Reliability § Security 4 System certification Innovation for a smarter planet 2

IBM Software Group | Rational software Key Concepts for Agility Improve quality through continuous feedback Verification Analysis Review Testing via execution or simulation Customer feedback (meet the need) Correctness Appropriateness Usability Defensive Design Primarily build executable things Verify them continuously Efficiency through Concentrate on high-value tasks Avoid rework Paying attention to how you’re doing against goals Project retrospective Risk management Active and continuous risk mitigation Planning Don’t plan beyond the fidelity of the information you have Plan enough but not more than that Adjust plans based on “truth on the ground” (metrics) Innovation for a smarter planet Dynamic planning Responsive to Change 3

IBM Software Group | Rational software What do we mean by “verification”? § Syntactic verification – “well-formedness” (compliance in form) 4 Performed by quality assurance personnel 4 Two types § Audits – work tasks are performed as per plan and guidelines § Syntactic review – work products conform to standard for organization, structure and format 4 Ex: § Requirements shall be uniquely numbered, be organized by use case, use the word “shall” to indicate the normative phrase of a requirement; functional requirements shall be modified by at least one quality of service requirement, … § Semantic verification – “correct” (compliance in meaning) 4 Performed by engineering personnel 4 Three basic techniques § Testing – requires Executability of work products, impossible to fully verify § Formal methods – strongest but hard to do and subject to invariant violation § Semantic review (subject matter expert & peer) – most common, weakest means Innovation for a smarter planet 4

IBM Software Group | Rational software What does “agile” mean for Systems Engineering? § Do what you need to do, no more and no less 4 This depends heavily on industry, regulation, and business environment 4 Provide the necessary level of rigor, precision, and repeatability 4 Often requires detailed traceability links among work products (e. g. requirements traceability) 4 Use tooling to automate manually-intensive, error-prone work § Work iteratively and incrementally 4 Group requirements with user stories or use cases 4 Incrementally add traceability 4 Incrementally develop system architecture § Verify work products continuously 4 With syntactic verification (Q/A) activities 4 With semantic verification 4 With customer (aka “validation”) § Outcome contains textual specifications but also linked executable specifications § Use dynamic planning to adjust project plans based on “ground truth” and responsiveness to change 4 Use goal-based metrics (KPIs) to track project progress 4 Continuously track progress against plan. Adjust planning frequently § Safety, Reliability, Dependability 4 Not “done once” but continuously assessed Innovation for a smarter planet 5

IBM Software Group | Rational software Best Practices for Agile Systems Engineering § High-fidelity model-based engineering (Hi-MBE) § Incremental functional analysis with use cases § Test-driven development of system specifications 4 Example: Requirements verification via executable requirements modeling with Sys. ML / UML § Project risk management § Incrementally add traceability § Integrated safety and reliability analysis § Model-based handoff to downstream engineering § Automated document generation from model artifacts Note: a key difference between agile SW and agile SE is that the outcome of SE is specifications and the outcome of SW is implementation Innovation for a smarter planet 6

IBM Software Group | Rational software Model-Based Systems Engineering and Agile? Innovation for a smarter planet 7

IBM Software Group | Rational software Advantages of MBSE § Precision 4 Models constructed in formal (or semi-formal) languages are more precise than text 4 Recommendation: Link description informal text to precise, formal models § Verification 4 Models can be executed, simulated, or (formally) analyzed § Requirements models § Architecture models § Dependability models § Control models § Improved Handoff from systems engineering to downstream engineering 4 Precise models are less likely to be misinterpreted 4 If systems and software engineers use the same modeling languages, then no translation is required § Improved understanding of architecture § Improved visualization of functional, structural, and behavioral aspects § Decreased design learning time Innovation for a smarter planet 8

IBM Software Group | Rational software Models and Viewpoints in Model-Based Systems Engineering Power Weight Stability Functional Model Heat Executable use cases Functional and Qo. S requirements Mechanical Specification Subsystems, interfaces, Subsystem use cases/ Requirements Trade study Model Architectural Model Trade study Model-b ased handoff Trade study Model Subsystem Model(s) Dependability Model Safety, reliability, and security analysis FTA, FMEA, FEMCA, Asset Diagram, SAD Innovation for a smarter planet Model and text Electronic Specification Model and text Control Model Control algorithms, mathematical models Software Specification Model and text 9

IBM Software Group | Rational software Scenario Driven Use Case Construction / Validation Making it Agile Loop Conceptualize requirement aspect Incrementally augment model Verify Repeat until all requirements added < 1 hr Repeat for all use cases Innovation for a smarter planet 10

IBM Software Group | Rational software Requirements Verification Using Rhapsody and Simulink Innovation for a smarter planet 11

IBM Software Group | Rational software Traceability in Models § Traceability is crucial for effective systems engineering § Traceability supports 4 Demonstration of congruence of different work products in different disciplines done by different people and managed by different tools 4 Impact analysis – the effects of change one element as it propagates through the set of related work products 4 Coverage analysis – ensure that related aspects in different work products are adequately represented § E. g. requirements test architecture design implementation safety assessment 4 Standards compliance required by industry standards Innovation for a smarter planet 12

IBM Software Group | Rational software Important to Relate Safety Information Through Lifecycle Innovation for a smarter planet 13

IBM Software Group | Rational software Integrated Safety and Reliability Analysis Innovation for a smarter planet 14

IBM Software Group | Rational software Model-Based Threat Analysis § Security Analysis Diagram (SAD) is like a Fault Tree Analysis (FTA) but for security, rather than safety 4 It looks for the logical relation between assets, vulnerabilities, attacks, and security violations 4 Permits reasoning about security § What kind? § How much? § Risk assessments Innovation for a smarter planet 15

IBM Software Group | Rational software Auto-generation of documents (summary data) Fault Source Matrix, Fault Detection Matrix, Fault-Requirement Matrix, FMEA, Hazard Analysis… Traceability improves your ability to make your safety/security case Generate documents are a natural (and automated) outcome of engineering work rather than as a separate activity Innovation for a smarter planet 16

IBM Software Group | Rational software Model-Based Hand-off to Downstream Engineering Innovation for a smarter planet 17

IBM Software Group | Rational software Special Considerations for Agile Systems Engineering § Do I have to complete SE before starting on the SW and HW work? • Requirements • Functional Analysis • Systems Architecture Systems Engineering Downstream Development • Software • Electronics • Mechanical • Optical • Chemical Innovation for a smarter planet • Integration • Verification • Flight Test • Validation • Customer acceptance Extreme case: Complete all SE before DSE - When there is significant novel hardware - When there is basic science to be done Verification & Validation 18

IBM Software Group | Rational software Special Considerations for Agile Systems Engineering § Do I have to complete SE before starting on the SW and HW work? Systems Engineering Extreme case: SE and DSE almost completely overlap - When there is no novel hardware - When development is low risk and well understood Innovation for a smarter planet Downstream Engineering Verification and Validation 19

IBM Software Group | Rational software Special Considerations for Agile Systems Engineering § Do I have to complete SE before starting on the SW and HW work? Systems Engineering The truth is usually somewhere in the middle - SE starts the engineering work - As independent parts of the specifications stabilize, DSE can begin - DSE continues in an incremental way as well, resulting in incremental V&V Innovation for a smarter planet Downstream Engineering Verification & Validation 20

IBM Software Group | Rational software Summary § Systems Engineering capability can be greatly enhanced with two key technologies 4 MBSE - Use of Sys. ML/UML Modeling to capture system § Functionality and Qualities of service (executable use cases) § Structure (architecture) § Model-based hand off to downstream engineering § Automatic generation of documentation from model-based work products 4 Agile methods employing § Incremental construction and verification of models § Test Driven Development nanocycle-level iteration § Incorporating dependability analysis with the SE workflow § Incremental traceability § Harmony best practice workflows can be employed in an agile way 4 Process guidance – linked guidance to performance of tasks and creation of work products 4 Project Planning – create project plans with Harmony process templates in Rational Team Concert 4 Project Governance – monitor KPIs in project dashboards Innovation for a smarter planet 21

IBM Software Group | Rational software References Innovation for a smarter planet 22