model-driven user requirements specification using sysml authors: michel dos santos soares, jos...
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Model-Driven User RequirementsSpecification using SysML
Authors: Michel dos Santos Soares, Jos Vrancken
Source:Journal of Software(JSW), Vol. 3, No. 6, 57-68, Jun 2008ISSN 1796-217X
Presenter:Ming-Chih LiESL, Dept. of CSIE, CCU2011/03/11
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Outline
Introduction A Proposed User Requirements
Classification User Requirements Specification Using
SysML Diagrams SysML Requirements Diagram Extensions Case Study Discussion Conclusion
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Introduction
Requirements engineering(RE) is an important phase in a system’s life cycle. When poorly performed failures, cost overrun and delays
RE can be divided into two main groups of activities Requirements development
Documenting and analyzing Requirements management
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Introduction (cont.)
Well-written user requirements documentation is fundamental as it facilitates later phases, not only during RE, but during the whole system life cycle.
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Introduction (cont.)
The increasing complexity of systems makes requirements engineering activities both more important and more difficult. large number of elements and reliability
factors must be decomposed into several
smaller components increase the level of abstraction Model-driven approaches
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Introduction (cont.)
UML and its profiles(e.g. SysML, MARTE) are the current dominant graphical languages used in model-driven approaches
This paper is about applying a Model-Driven Requirements
Engineering approach based on SysML
Requirements diagrams Use Case diagrams
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Introduction (cont.)
First, a classification for each atomic requirement is proposed
the SysML Requirements diagram is used to represent graphically single user requirements and their relationships
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Introduction (cont.)
Then, User requirements are also represented in a tabular format, which may facilitate requirements tracing during the system life cycle.
Finally, SysML Use Case diagrams are applied to represent the actors involved and the use cases, giving a context diagram delimiting the system
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Introduction (cont.)
After being structured and graphically represented, user requirements may be detailed into systems requirements
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A Proposed User Requirements Classification
A common classification proposed for requirements is based on the level of abstraction functional
describes what the system should do non-functional
are related to emergent system properties, such as reliability and performance
external a detailed description of all inputs into and
outputs from the software system
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User Requirements Specification Using SysML Diagrams
The SysML Requirements Diagram is a stereotype of the UML Class diagram
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User Requirements Specification Using SysML Diagrams (cont.)
Requirements relationships hierarchy derive satisfy
dependency relationship between a requirement and a model element
verify how a test case can verify a requirement
refine trace
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User Requirements Specification Using SysML Diagrams (cont.)
Requirements Table This allows an agile way to identify,
prioritize and trace requirements
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User Requirements Specification Using SysML Diagrams (cont.)
The SysML Use Case Diagram The SysML Use Case diagram is derived
without important extensions from the UML 2.0 Use Case diagram
The Use Case diagram shows system functionalities that are performed through the interaction of the system with its actors.
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SysML Requirements Diagram Extensions
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Type: tagged valuese.g. Performance, Security and Efficiency for non-functional req. User, Hardware, Software and Communication for External Interface req.
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SysML Requirements Diagram Extensions (cont.)
Grouping Requirements Requirements may be decomposed into
atomic requirements, and may later even be related in the sense that together they are capable of delivering a whole feature
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Case Study
The case study is based on a document with 79 atomic requirements for a road traffic management system.
We have selected in this paper to model the requirements of the Traffic Manager(TM, 10) and the Traffic Management Center(TMC, 8).
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Case Study (cont.)
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Case Study (cont.)
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Discussion
natural language is the only description of requirements ambiguity, lack of easy visualization and
impossibility to analyze and simulate. SysML is a language
is highly customizable and can be extended into families of languages
Profiles may specialize language semantics, provide new graphical icons and domain-specific model libraries
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Conclusion (cont.)
It is essential to have properly-structured and controlled requirements specifications
requirements tables are useful to represent decomposition in a tabular form and improve traceability
Using a specific diagram for requirements is a SysML advantage over UML
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Conclusion
An extension to the basic SysML Requirements diagram is proposed, based on a classification for user requirements
It is also shown that related requirements can be grouped, which can be seen as an initial system decomposition into subsystems
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Thanks for your listening
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