U(ML)2 – The New Driving Force

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Ames Laboratory
US Department of Energy
Quo Vadis Systems Engineering?
First Experiences with UML 2.0 and the Telelogic Tau Developer
Christian Schröder
University of Applied Sciences, Bielefeld, Germany
Ames Laboratory, US Department of Energy, Ames, Iowa, USA

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Main Collaborators
� Dirk Mikosch, Wolfgang Sonntag (Telelogic)
� Peter Braun, Martin Rappl (TU München, Chair of M. Broy)
� Michael von der Beeck (BMW Group)
� Carl K. Chang, Glenn Luecke (Iowa State University)
� Dave Turner (Ames Laboratory)
� Students
� Jan Gatting
� Felix Hartmann
� Jakob Töws
� André Wehe
Ames Laboratory
US Department of Energy

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Contents
� Key Concepts in Systems Engineering
� Pervasive Model-Based Systems Engineering
� Quo Vadis Systems Engineering?
� Recent Advances in Systems Engineering
� FORSOFT II – Project Automotive
� U(ML)2 – The New Driving Force
� UML 2.0 – New Challenges
� Conclusions
� UML 2.x – New Frontiers
Ames Laboratory
US Department of Energy

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Key Concepts in Systems Engineering
Pervasive Model-Based Systems Engineering
� Model-Based:
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US Department of Energy
� keep one information model, provide as many views (diagrams,
tools) as necessary
� support information model representation by various notations
� perform model manipulation on views rather than on the model
itself
View 1
View 3
View 2
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Key Concepts in Systems Engineering
Model-Based Systems Engineering
Ames Laboratory
US Department of Energy
[Source: Douglas R. Hofstadter: Gödel, Escher, Bach: An Eternal Golden Braid]

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Key Concepts in Systems Engineering
� Meta-Model Orientation
Ames Laboratory
US Department of Energy
� structure system information model by means of a meta-model
� employ meta-model patterns to reduce complexity
� provide basis for model transformations and tool coupling
*
SuperReceiver
0..1
Propagator
*
OutPort
FunctionOutPort
attached
0..1
Caller
1
*
Function
1
1
attached
*
FunctionVariable
SubFunction
Variable
0..1
SuperFunction
attached
*
Callee
*
InPort
FunctionInPort
*
SubReceiver
0..1
Delegator

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Key Concepts in Systems Engineering
Meta-Model Orientation – Providing a Tool Coupling Mechanism
Ames Laboratory
US Department of Energy
P. Braun, F. Marschall. Transforming
Object Oriented Models with BOTL.
International Workshop on Graph
Transformation and Visual Modeling
Techniques, number 72.3 in ENTCS.
Elsevier Science B. V., 2002.

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Key Concepts in Systems Engineering
� Pervasiveness
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US Department of Energy
� use the very same concepts throughout the whole development
process
� define abstraction layers to constrain the design space (and
cope with complexity)
� cf. 3 abstraction layers of MDA* (CIM - computational
independent model, PIM - platform independent model, PSM -
platform specific model)
� use abstraction layers and meta-model (patterns) to structure
information model as well as user model and process
*J. Miller and J. Mukerji. MDA guide version 1.0, May 2003.

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Recent Advances in Systems Engineering
*M. von der Beeck, P. Braun, M. Rappl, C. Schröder, „Automotive UML – A Metamodel-
Based Approach for Systems Development”, „UML for Real: Design of Embedded Real-Time
Systems“, Kluwer Academic Publishers, ISBN 1-4020-7501-4, 2003 and references therein
Ames Laboratory
US Department of Energy

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FORSOFT II – Automotive
Project Goals
� Define a pervasive model-based methodology for automotive
systems development, i.e.
� an integrated meta-model based information model,
Ames Laboratory
US Department of Energy
� an abstract modeling language, AML – Automotive Modeling
Language,
� AML‘s concrete representation aligned to standard UML 1.x,
� a system of structuring abstraction layers,
� a meta-model based requirements engineering method,
� a supporting tool chain consisting of Telelogic DOORS, Telelogic
UML Suite, ETAS ASCET SD

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Automotive Core Concepts
Automotive Modeling Language AML
� Starting point: “Don’t invent the wheel again!” – use well-known,
recurring and proven Architecture Description Language (ADL)
concepts (i.e. SDL, ROOM, etc.):
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US Department of Energy
ADL = Components + Ports + Connectors + Styles
� support formation of variants
� support classification of requirements
� provide notation-free definition
� provide language mappings, i.e. textual and graphical form
� Starting point: ”Don’t wag the dog!” – stay close to standards, use
UML 1.x!

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Automotive Core Concepts
Uniform Structuring Mechanism
� System of abstraction layers
� define restrictive views on the system
model to structure and filter information
� each abstraction layer is based upon a
higher, i.e. a more abstract layer
� transitions from a higher layer to lower
layer means restriction of the design
space
Ames Laboratory
US Department of Energy
Signals
Functions
Integrated
Network
System model
Functional Network
Logical Architecture
Technical Architecture
Implementation

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Automotive Core Concepts
Realized pervasive meta-model based approach
AML Metamodel
Requirements
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US Department of Energy
«tailors»
UML Metamodel
«classified by» «defined by» «instance of»
«realize»
User Models
meta-model
level
user model
level

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Automotive Core Concepts
Meta-model based approach for Requirements Management
Ames Laboratory
US Department of Energy
AML-Metamodel
Requirements Classification
Requirements
Formal
Requirements
Informal
Requirements
«tailors»
UML-Metamodel
«classified by» «defined by» «instance of»
«evolve»
«realize»
Models
meta-model level
user model level

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Automotive Core Concepts
Informal
Requirements
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US Department of Energy
rules for structuring
Formal
Requirements
tight integration
“1:1”
Specification
� Unstructured
� Redundant
� Incomplete
� Inconsistent/ambigious
Structure aligned to
specification
Less redundant
Complete
(Meta-)model based
Consistent

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Automotive Core Concepts
Meta-model oriented derivation of structuring rules
DOORS view
Ames Laboratory
US Department of Energy
1
Project
-Name : String
1
*
1 *
*
Function
LogicalArchitecture
Signal
UML Suite view
ASCET SD view

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Automotive Core Concepts
Example: AML meta-model fragment for the definition of a
function (abstract syntax)
Ames Laboratory
US Department of Energy
*
SuperReceiver
0..1
Propagator
*
OutPort
FunctionOutPort
attached
0..1
Caller
1
*
Function
1
1
attached
*
FunctionVariable
SubFunction
Variable
0..1
SuperFunction
attached
*
Callee
*
InPort
FunctionInPort
*
SubReceiver
0..1
Delegator

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Automotive Modeling Language
� Example: UML 1.x Language Mapping (concrete syntax)
AML Concept
Function
Decomposition
FunctionInPort
FunctionOutPort
Instance
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US Department of Energy
UML Language Mapping
Folded Class
Environment Class
Interface Class / Lollipop
Dependency arrow
Component
BasicOperation
«environment»
@WindowLifting
SwitchMovement
[Movement]
WL_FrontLeft
[DriverDoor]

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Automotive Modeling Language
� Example: function definition “WindowLifting”
Ames Laboratory
US Department of Energy
BasicOperation
ChildProtection
RepetitionLock
BlockDetection
SwitchMovement
[Movement]
BOControl
[Control]
CPControl
[ControlFlow]
RLControl
[Control]
UsedMotorTime
[Time]
BDControl
[Control]
SensorSignalsMotor
[CurrentSignals]
UsedMotorTime
[Time]
WindowControl
[ControlFlow]
MotorMovement
[Movement]
«environment»
@WindowLifting
MotorMovement
[Movement]
Motor

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Automotive Modeling Language
� Example: functional network (variant instance view)
Ames Laboratory
US Department of Energy
FL_SwitchMovement
[Movement]
WL_FrontLeft
[DriverDoor]
FL_WindowControl
[Control]
BL_WindowControl
[Control]
WL_BackLeft
[PassengerDoor]
BL_SwitchMovement
[Movement]
FR_SwitchMovement
[Movement]
WL_FrontRight
[DriverDoor]
FR_WindowControl
[Control]
BR_WindowControl
[Control]
WL_BackRight
[PassengerDoor]
BR_SwitchMovement
[Movement]

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Results
� Open(!) integration of 3 CASE
tools
� common metamodel
� transformation based on
models
� Transformation
� graphical and abstract
� Minimized information exchange
� AML specific information vs.
� tool specific information
� Consistent storage of information
by assigning
� global (AML specific) and
� local (tool specific) identifier
Ames Laboratory
US Department of Energy
ASCET-SD
UML Suite
DOORS

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Results
Serious UML 1.x weaknesses detected!*
� missing concept hierarchical decomposition
� divide and conquer (top down)
� building blocks (bottom up)
� bidirectional interface
� missing concept for logical components
� missing concept for mapping to physical components
� missing concept for encapsulation
� black-box approach for just the right level of detail
� …
*M. Broy, M. von der Beeck, P. Braun and M. Rappl: A fundamental critique of
the UML for the specification of embedded systems, unpublished, 2000
Ames Laboratory
US Department of Energy

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Ames Laboratory
US Department of Energy
Time for Divorce!

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U(ML)2 – The New Driving Force
Who was first? Egg or Hen?
� A new generation tool: Telelogic’s Tau Developer (released
October 2002)
� A new generation language: UML 2.0 (adopted by OMG June
2003)
Ames Laboratory
US Department of Energy

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U(ML)2 – The New Driving Force
� Language benefits for systems engineering
� a picture says more than 1000 words …
Ames Laboratory
US Department of Energy
SDL MSC
UML
Other
modeling
languages
[Source: Cris Kobryn, UML 2.0 Roadmap]

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U(ML)2 – The New Driving Force
� Tool benefits for systems engineering
� Graphical development tool
� Editing
� Simulation / Verification
� Application generation
� Based on UML 2.0 (as proposed by U2 Partners)
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� Model-based architecture
� Extensive Model Verification capabilities
� Textual UML syntax
� Open and extendible
� compliant with standards, API’s, “pluggable” interface add-in,
code generators, etc.

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U(ML)2 – The New Driving Force
� A new approach! U(ML) 2 language mappings for the AML
AML Concept
Function
Decomposition
FunctionInPort
FunctionOutPort
Instance
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US Department of Energy
UML 2.0 Language Mapping
Active Class
Internal Structure
Port + provided Interface
Port + required Interface
Part
BasicOperation
MotorMovement
UsedMotorTime
Motor
Motor
a_BO:BasicOperation
BOPort

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U(ML)2 – The New Driving Force
� Example: function definition for “WindowLifting”
Ames Laboratory
US Department of Energy
a_motor:Motor
active class WindowLifting {1/2}
SwitchMovement, BOControl
a_BO:BasicOperation
BOPort
a_CP:ChildProtection
CPPort
WindowControl
WLPort
a_RL:RepetitionLock
RLPort RLControl WindowControl
UsedMotorTime
a_BD:BlockDetection BDPort
CPControl
MotorMovement
SensorSignalsMotor, UsedMotorTime
BDControl
MotorMovement
WindowControl

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U(ML)2 – The New Driving Force
� Example: functional network (variant instance view)
Ames Laboratory
US Department of Energy
WL_FrontLeft:DriverDoor
WindowControl
SwitchMovement
SW_Port
WL_BackLeft:PassengerDoor
WL_FrontRight:DriverDoor
WL_Port
WindowControl
WL_Port
WindowControl
SW_Port
WL_Port WL_Port
SW_Port
SwitchMovement
SwitchMovement
WL_BackRight:PassengerDoor
SW_Port
SwitchMovement

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U(ML)2 – The New Driving Force
Conclusion
� Better language support compared to UML 1.x
� bidirectional interfaces/ports, encapsulation, connectors …
� Better tool support
� support for model-based software development due to truly modelbased
tool architecture
� simulation possible! (however, not yet used)
Current work
� Complete AML language mapping to UML 2.0
� UML 2.0 Automotive profile
� Improving tool support
� tailoring Tau Developer to Automotive profile
� Further studies on usage of UML 2.0 in the Automotive Domain
Ames Laboratory
US Department of Energy

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UML 2.0 – New Challenges
Development and Simulation of CAN Based
ECU Architectures with UML 2.0
Ames Laboratory
US Department of Energy
F. Hartmann 1,2 , D. Mikosch 2 , and C. Schröder 2
1Telelogic Deutschland GmbH, Bielefeld
2University of Applied Sciences, Bielefeld

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UML 2.0 – New Challenges
Idea:
� Definition of a UML 2.0
CANdb profile
� Import of standard
CANdb into Tau
Developer
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US Department of Energy

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UML 2.0 – New Challenges
� Automatic generation of profile/model elements (nodes,
messages) according to system description in CANdb
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US Department of Energy

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UML 2.0 – New Challenges
� Modeling and simulation of the network within Tau Developer
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US Department of Energy

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UML 2.0 – New Challenges
Automated Model Testing with UML 2.0 and
TTCN 3 – Integrating Telelogic’s Tau
Developer and Tau Tester
Ames Laboratory
US Department of Energy
J. Töws 1,2 , D. Mikosch 2 , and C. Schröder 2
1Telelogic Deutschland GmbH, Bielefeld
2University of Applied Sciences, Bielefeld
... more about this project in the near future ...

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Conclusion
Quo Vadis Systems Engineering?
� Eventually UML 2.x will not only merge proven (standard)
languages, but also benefit from the vast field experiences
made by supporting companies and institutions (just look at the
members of the U2 Partners group!)
� Better tool support (and model exchange) due to better
language architecture (eventually leading to MDA)
� Model verification, simulation, testing …
� First chance to realize – practically – the concept of pervasive
model-based systems engineering within a standardized
language framework
� Further definition and realization of domain profiles
Ames Laboratory
US Department of Energy

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UML 2.x – New Frontiers
� Model-based Requirements Engineering
� Function-class decomposition method*, i.e.
integration of structured (functional) analysis with
OO approach (joint project with Carl K. Chang, ISU)
� “System-on-Chip design with UML” (initiative
recently started by Grant Martin, Cadence Design
Systems)
� Combined modeling of event driven and
continuous time behavior
� Using UML 2.0 and MPI for automatic code
generation for high performance parallel and
cluster computing (joint project with ISU and
Ames Laboratory)
*C. K. Chang, J. Cleland-Huang, S. Hua and A. Combelles, “On Function-Class
Decomposition”, IEEE Computer, Dec. 2001, pp. 87-93.
Ames Laboratory
US Department of Energy

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Ames Laboratory
US Department of Energy
Thank you for your attention!
email: schroder@ameslab.gov
christian.schroeder1@fh-bielefeld.de

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Supplement
Function-Class Decomposition (abstract by Carl. K. Chang)
In addition to offering a simple yet powerful method for decomposing a system,
function-class decomposition (FCD) produces an architecture that is more
supportive than traditional object-oriented decomposition for several software
engineering tasks. A hybrid method that integrates structured analysis with an
OO approach, FCD identifies classes in parallel with decomposing the system
into a hierarchy of functional modules. Recently, developers extended FCD to
integrate UML concepts. Useful for partitioning a system for distribution, the
FCD hierarchy provides a framework for controlling development in a distributed
software engineering environment. It also helps identify and integrate
components in component-based development and supports the system lifecycle
maintenance phase. Further, FCD addresses many of the initial analysis
and design problems inherent in large and complex OO systems. The authors'
experience with testing FCD on several applications validates its compatibility
with OO methodologies and modeling techniques. In addition to supporting the
decomposition process itself, the resulting FCD architecture and related artifacts
support maintenance of the system in the face of changing requirements.
Ames Laboratory
US Department of Energy