2. Motivation
➔ Increasing Complexity of Systems
➔ Proposed approach to RE
➔ State of the Art
➔ Advantages
➔ Challenges
➔ Keywords - Requirements Engineering, Model-driven Engineering,
SysML, UML
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3. Outline
➔ Few words about the Paper
➔ Citations and Impact
➔ Understanding Systems Engineering
➔ Brief overview of Real-time Systems
➔ Introduction to Model-driven Engineering
➔ Role of UML in MDE
➔ Introduction to SysML
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4. Outline
➔ Core of the Paper
➔ Case Study
➔ Conclusion
➔ Questions
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5. The Paper
➔ “Model Driven User Requirement Specification using SysML”
➔ It is an extended version of the paper “ Requirement Specification
and Modeling through SysML (ISBN 1-4244-0991-8)”
➔ By: Michel dos Santos Soares and Jos Vrancken
➔ Work done at: Next Generation Infrastructures Research Center of
TU Delft, Netherlands
➔ Appeared in: IEEE International Conference on Systems, Man and
Cybernetics in 2007
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6. Citations and Impact
➔ Moderate Citation
➔ 23 (37 main paper) citations in Google Scholar
➔ 9 citations in CiteSeerX (Searched with ISBN)
➔ 1,450 results in Google (Searched with ISBN)
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7. Systems Engineering
➔ “Systems engineering” is an approach and engineering discipline.
➔ Deals with complex systems.
➔ Realized through software and hardware solutions.
➔ Relies on modeling and simulation to evaluate the system.
➔ Modeling is a common practice.
➔ Heterogeneous team.
➔ Example: Avionic Systems
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8. Real-time Systems (I)
➔ Subject to a "real-time constraint".
➔ Missing a deadline by milliseconds could be a total system failure.
➔ Often Mission and/or Safety critical.
➔ Normally failure is NOT an option.
➔ Dependable and fault tolerant.
➔ Example: Embedded System.
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10. Model-driven Engineering
Model has a graphical representation instead of only a textual one.
➔ In MDE models are the main artifact during system development.
➔ MDE addresses system complexity by intense use of models.
➔ MDE is a model-based approach (MBE).
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11. Role of UML in MDE
➔ UML is the standard modeling language in software community.
➔ A lingua franca in object-oriented analysis and design.
➔ Serving it's purpose quite well since it's inception.
➔ UML and it's extensions “UML profiles” are the current dominant
graphical languages used in model-driven approaches (MDA, MDD,
MDE).
➔ Limitations.
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12. Introducing SysML (I)
➔ Initiated in 2001 by the INCOSE (International Council on Systems
Engineering)!!
07/2006 : SysML is officially adopted by the OMG
09/2007 : SysML v1.0
12/2008 : SysML v1.1
06/2010 : SysML v1.2 (current version)
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13. Introducing SysML (II)
➔ SysML is based on UML and reuses a subset of UML2 (UML4SysML)
➔ Provides a vocabulary more suitable for systems engineering,
➔ Involves modeling blocks instead of modeling classes.
➔ A block encompasses software, hardware, data, processes, personnel
and facilities.
➔ Helps bridge the semantic gap between systems, software and other
engineering disciplines.
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15. Introducing SysML (IV)
➔ SysML also supports allocation tables.
➔ These allocation tables support common kinds of allocations
➔ Requirements allocation,
➔ Functional allocation,
➔ and Structural allocation.
➔ SysML defines new types of comments, introducing stereotypes !
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16. Core of the Paper (I)
➔ Requirements for a System are a collection of needs expressed by
stakeholders respecting some constraints under which the system
must operate.
➔ Requirements can be classified in
➔ User requirements vs Systems requirements
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17. Core of the Paper (II)
➔ The process by which requirements for systems and software
products are gathered, analyzed, documented and managed through
out the development life-cycle is called Requirements Engineering
(RE).
➔ RE can be divided into two main groups of activities.
● Requirements Development
● Requirements Management
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18. Core of the Paper (III)
➔ Requirements Documentation
➔ Graphic-based
➔Use cases
➔Limitations (functional vs non functional)
➔ Purely textual
➔User stories (XP)
➔Limitations ( imprecision, ambiguity,....)
➔ Combination of both
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19. Core of the Paper (IV)
➔ Proposed approach
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20. Core of the Paper (V)
➔ Proposed User Requirements Classification
➔ Functional
➔ Non-functional
➔ External (inputs into and outputs from the system)
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21. Core of the Paper (VI)
➔ SysML Requirements Diagram and it's extensions
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23. Core of the Paper (VIII)
➔ SysML Use Case Diagrams
➔ Derived without important extensions from UML 2.0
➔ Main difference is the more wide focus (not only software)
➔ Diagrams are composed of
➔Actors
➔Use cases
➔Relationships
➔Communication (used to associate actors and use cases)
➔Generalization (from actor-to-actor/usecase-to-usecases)
➔Include and Extend (mechanism for event encapsulation)
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24. Case Study (I)
➔ Based on a document with 79 atomic requirements
➔ For a road traffic management system
➔ Requirements are based on a series of interviews and studies with stakeholders
➔ Stakeholders were classified as:
➔ the Road Users (1),
➔ the Ministry of Transport, Public Works and Water Management (2),
➔ the Traffic Managers (10),
➔ The Traffic Management Center (8),
➔ the Task, Scenario and Operator Manager (22),
➔ the Operators (4),
➔ the Designers of the Operator’s Supporting Functions (15),
➔ and the Technical Quality Managers (17)
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30. Conclusion
➔ SysML is a language, not a methodology!
➔ SysML can be easily understood by software community due to it's relation to UML2.
➔ SysML makes it possible to generate specifications in a single language for heterogeneous
teams.
➔ Supported by wide range of contributors from industry, tool vendors and government
agencies.
➔ Please refer to: http://www.sysml.org/
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