University of Southern California
Center for Systems and Software Engineering
Model-Based Software
Engineering
Supannika Koolmanojwong
Spring 2013
University of Southern California
Center for Systems and Software Engineering
Outline
• Model-Based Software Engineering
• Agile MDA
• Agile Modeling
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University of Southern California
Center for Systems and Software Engineering
Related Concepts
• MBASE – Model-Based (System) Architecting
and Software Engineering (by CSSE USC)
– Product, Process, Property, and Success models
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MBE – Model-Based Engineering
MDE – Model-Driven Engineering
MDD – Model-Driven Development
MDA – Model Driven Architecture
Model-Based Software Development
Model-Based Testing
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University of Southern California
Center for Systems and Software Engineering
What is Model-based ______ ?
• Designing before coding
• Benefits of Model-based software
engineering ?
• A model is an abstraction – it gives a high-level description
of objects
– Technology independent model
• Models are often graphical
• Reduce development time; simplify the process of design
– Using design pattern
• Improve application quality while reducing testing time
• Reduce maintenance cost and Total Cost of Ownership of
enterprise applications
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University of Southern California
Center for Systems and Software Engineering
Model-driven architecture
• Separate design from architecture
• The design
– Addresses the functional (use case)
requirements
• The architecture
– Provides infrastructure through which LOS
requirements are realized
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University of Southern California
Center for Systems and Software Engineering
MDA models
• Computational Independent Models
– Business models
• Technology (Platform) Independent Models
• Technology (Platform) Specific Models
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University of Southern California
Center for Systems and Software Engineering
OMG MDA
University of Southern California
Center for Systems and Software Engineering
OMG Technology (SysML)
University of Southern California
Center for Systems and Software Engineering
OMG Technology (SysML)
University of Southern California
Center for Systems and Software Engineering
Requirement Diagram
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University of Southern California
Center for Systems and Software Engineering
Block Definition Diagram
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University of Southern California
Center for Systems and Software Engineering
Advantages
• Independence of a specific programming
language
• Predict bottlenecks and constraints
• Predict system performance
• More detailed abstraction levels
• Achieve high complexity
• Encourages good OO
University of Southern California
Center for Systems and Software Engineering
Advantages (continued)
• Can communicate effectively with
stakeholders by providing a model.
• Create a roadmap for developers to follow.
• Track the history of every decision.
(essential for Embedded Systems!)
• Represents things in thin air (like network
or internet components)
University of Southern California
Center for Systems and Software Engineering
Disadvantages
• More time modeling and less time coding
(if you enjoy coding).
• Usability of generated code.
University of Southern California
Center for Systems and Software Engineering
Outline
• Model-Based Software Engineering
• Agile MDA
• Agile Modeling
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University of Southern California
Center for Systems and Software Engineering
Agile MDA
• Agile MDA is based on the notion that code
and executable models are operationally
the same.
– testing first
– immediate execution
– short cycles
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http://www.omg.org/mda/mda_files/AgileMDA.pdf
University of Southern California
Center for Systems and Software Engineering
Agile MDA
• Types of Models
– Sketch
• To brainstorm some idea
– Blueprint
• Can be used as a construction plan
• Mostly for manufacturing system
– Executable model
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University of Southern California
Center for Systems and Software Engineering
Agile MDA
• No analysis or design model
– but different model to capture independent
aspects of the system
• Build executable UML model
– Class, state diagrams
• Some diagrams are not executable, but
provide foundations to others
– Use Case diagram
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University of Southern California
Center for Systems and Software Engineering
Agile MDA
Class Diagram
State Diagram
Object Diagram
• Technology Independent Model
• Encourage clients to participate in the
architecture development
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University of Southern California
Center for Systems and Software Engineering
Agile MDA
• Why use action models, why not code
directly ?
• Action semantics allows you to specify
behavior without relying on knowledge of
the implementation
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University of Southern California
Center for Systems and Software Engineering
Agile MDA
• Merge the models
– Map them together
– Example:
• The class Teller and the class Customer in
the Bank model each correspond to an
instance of a Role in the Security model
• Each Account instance in the Bank
corresponds to an instance of
ProtectedResource in Security
• a subset of Train instances in a control
application corresponds to instances of Icon
in a User Interface domain
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University of Southern California
Center for Systems and Software Engineering
Agile MDA
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University of Southern California
Center for Systems and Software Engineering
Agile MDA
• Model Compiler
– Mapping functions from various models
– Executable UML becomes meta model for
individual models that compiler weaves
together
• Architectural mismatch !!
– Transform models to java / C++
• Several techniques such as archetype, QVT
• Adding code bodies
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University of Southern California
Center for Systems and Software Engineering
Outline
• Model-Based Software Engineering
• Agile MDA
• Agile Modeling
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University of Southern California
Center for Systems and Software Engineering
Agile Modeling
• Methodology for effective modeling and documentation of softwarebased systems
http://www.agilemodeling.com/
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University of Southern California
Center for Systems and Software Engineering
Agile Modeling – Document Late
• Create document just before you deliver them; wait until the
unit has stabilized; Document the as-built system
• Risky to capture speculative information – requirements,
design
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University of Southern California
Center for Systems and Software Engineering
Document late
• Model and plan early, but don’t write detailed documents
• JIT detailed specifications
– Prefer to write executable specifications
• in the form of tests, not static document
• Supporting documents – user manuals
– Write once the system has stabilized
– Treat documentation as requirement (has prioritization level)
• System overview documentation
– Higher quality code with a regression test-suite for their code
• Lower cost curve
– Document early increase documentation maintenance costs
• Reduce financial risk and accuracy risk
• Increase delivery risk and accuracy risk (might forget
something)
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University of Southern California
Center for Systems and Software Engineering
Document Continuously
• Deliverable documentation
– Part of the overall solution to deliver to
customers
• Use Agile documentation style
– Wait for info to stabilize
– Document during long iteration
– For short iteration (2 weeks) – unlikely that the
info will stabilize in time, may document in the
next iteration.
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University of Southern California
Center for Systems and Software Engineering
Architecture Envisioning
- Agile Model Driven Development
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University of Southern California
Center for Systems and Software Engineering
Model Storming
• JIT modeling – stand-up design session;
customer Q&A session
• Analysis Model
• Design Model
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University of Southern California
Center for Systems and Software Engineering
Analysis Model
• Simple tool
• Need Active Stakeholder Participation
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University of Southern California
Center for Systems and Software Engineering
Design Model
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University of Southern California
Center for Systems and Software Engineering
Look Ahead Modeling
• Sometimes JIT is not enough
• Stakeholders unavailability
• Difficult requirements/ solution
– Need experts to work through them before
explaining to developers
• Need to integrate with poorly documented
legacy asset
• Usability issues – usability modeling an
iteration ahead of the actual development
• Speed up development
• Potential conflict
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University of Southern California
Center for Systems and Software Engineering
References
• http://www.omg.org/mda/mda_files/AgileM
DA.pdf
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