Sys ml presentation

Intoduction to SysML
– a modeling language for Systems Engineering
SummIT 2013,
Axelborg 22. maj 2013
Ingeniørdocent Finn Overgaard Hansen,
foh@iha.dk
Department of Engineering
Aarhus University
Ver. 22.5.2013

Agenda
Systems Engineering and SysML
What is SysML?
New SysML concepts and diagrams
1. SysML Requirements
2. SysML Structure
3. SysML Behaviour
4. SysML Parametric
Perspectives for SysML & Summary

Model Based
Systems Engineering (MBSE)
• From a document-based to a model-based
approach
• A model-based approach requires modeling
concepts and tools
• MBSE: producing and controlling a coherent
System Model
• SysML is created to realize an MBSE approach
based on a System model of the wanted system
• SysML is a modeling language not a System
Engineering (SE) process

What is SysML?
• A graphical modeling language created in
response to the UML for Systems Engineering
RFP developed by OMG and INCOSE.
– a UML Profile that represents a subset of UML 2 with
important extensions
• Supports the specification, analysis, design,
verification and validation of systems that
include hardware, software, data, personnel,
procedures, and facilities
• Supports model and data interchange via XMI
SysML is a Critical Enabler for Model Driven or
Model Based Systems Engineering

SysML Specification
- History and Status
• Nov. 1997: UML V1.1 launched by OMG
• March 2003: The UML for Systems Engineering RFP
(Request for Proposal) was developed jointly by OMG and
INCOSE
– The SysML specification was developed in response
to these requirements by the diverse group of tool
vendors, end users, academia, and government
representatives
• July 2005: UML V2.0
• Sept. 2007: OMG SysML v.1.0
• Nov. 2008: OMG SysML v1.1 (256 pages)
• June 2012: OMG SysML v.1.3 (doc.id: 2012-06-01, 250 pages)

System Model and
HW/SW Components
SysML
UML

Comparison of SysML
and UML

SysML Diagram Taxonomy
SysML
Diagram
Behavior
Diagram
Requirement
Diagram
Structure
Diagram
Block
Definition
Diagram
Internal
Block
Diagram
Package
Diagram
Parametric
Diagram
Use Case
Diagram
State
Machine
Diagram
Sequence
Diagram
Activity
Diagram
Same as UML 2.x
Modified from UML 2.x
New Diagram Type

The 4 Pillars of SysML
1:
2: 3:
4:

1. SysML Requirements
• Requirement Diagram – a NEW diagram type
• Graphical visualization of requirements
– Functional
– Non-functional
• Requirements can graphical be related to:
– Other requirements
– Design elements
– Test Cases
• Standard stereotypes:
– derive, satisfy, verify, refine, trace and copy
– Used for requirement traceability

Requirements Diagram (req) - Example

Requirements Traceability - Example

2. SysML Structure
• UMLs class concept is replaced with the Block
concept
• A Block connects to other blocks via Ports
• Class diagrams are replaced with Block
Definition Diagrams (bdd)
• Each Block has an Internal Block Diagram
(ibd) where the internal parts are connected via
ports
– a replacement for class composite diagrams
• Ports can connect discrete as well as
continuous flows of material or information

Blocks are Basic Structural Elements

Block Definition Diagram (bdd) - Example

Internal Block Diagram (ibd) for an
Automobile Domain
Port

Internal Block Diagram (ibd) - Example
Part
Running the Vehicle Software

Proxy Ports
<>
Ibd [Block] Camera [Nested flow]
:Electronic Assembly
:MPEG Converter
:Image Processor
:Video
:MPEG4
:Image
camera i/o:
Camera
Interface
:Light
:Camera Module
:Optical Assembly
:Imaging Assembly
:Light
:Light
:Image
Proxy port
«flow specification»
Camera Interface
flowProperties
out digital video: MPEG4
out analog video: Composite
in control: Control Data
in startup sig: Start Up

Standard service based Ports (Full port)
Monitoring Station
Camera
Control camera requests
getCameraStatus(in cameraId: Integer, in cameraStatus: String)
testCameras()
panCamera(in strength: Integer)
tiltCamera(in strength: Integer)
operations
Camera Control
«interface»
Provided
interface
Required interface

3. SysML - Behavior
• Activity diagrams are enhanced with new
concepts
• Flows can be continuous and model
information as well as material flow
• Control flows are introduced
• SysML activities are based on token-flow
semantics related to Petri-Nets
• Tokens corresponds to values of inputs, outputs
and control
• Activities can have pins (acting as a buffer)

Activity Diagram (act) Notation
Flows can be discrete, streaming or control

Activity Diagram (act) - Example
swimlanes

Activity Diagram - decomposed
:CollectImages
:CaptureVideo
:GenerateVideo
Outputs
«optional»
current image
{stream}
captured image
{stream}
«optional»
MPEG output
{stream}
«optional»
Composite out
{stream}
act Operate Camera [Object Flow]
Object flow
video out
{stream}
input signal
{stream}
Have subdiagrams
Activity parameter
node

4. SysML Parametric
• Parametric Diagram (par) – a NEW diagram type
• Used to express constraints (equations) between value
properties
– Provides support for engineering analysis (e.g., performance,
reliability)
• Constraint block captures equations shown on a bdd
– Expression language can be formal (e.g., MathML, OCL) or informal
– A computational engine is defined by applicable analysis tool and not
by SysML
• Parametric diagrams represents the usage of the
constraints in an analysis context
– Binding of constraint usage to value properties of blocks (e.g., vehicle mass
bound to F= m × a)
• Parametric enable integration of engineering analysis
with design models

BDD Parametric Constraint Blocks
Stereotype

Parametric Diagram (par)
- Example for a block
Value bindings

Cross Connecting Model Elements
req [package] VehicleSpecifications
[Requirements Diagram - Braking Requirements]
Braking Subsystem
Specification
Vehicle System
Specification
id=“102”
text=”The vehicle shall stop
from 60 mph within 150 ft
on a clean dry surface.”
«requirement»
StoppingDistance
id=”337"
text=”Braking subsystem
shall prevent wheel lockup
under all braking conditions.”
«requirement»
Anti-LockPerformance
«deriveReqt»
Braking Subsystem
Specification
Vehicle System
Specification
id=“102”
«requirement»
StoppingDistance
SatisfiedBy
«block»Anti-LockController
id=”337"
«requirement»
«deriveReqt»
act PreventLockup [Activity Diagram]
DetectLossOf
Traction
Modulate
BrakingForce
TractionLoss:
par [constraintBlock] StraightLineVehicleDynamics [Parametric Diagram]
:Accelleration
Equation
[F = ma]
:VelocityEquation
[a = dv/dt]
:DistanceEquation
[v = dx/dt]
:BrakingForce
Equation
[f = (tf*bf)*(1-tl)]
tf: bf:tl:
f:
F:
c
a:
a:
v:
v:
x:
ibd [block] Anti-LockController
[Internal Block Diagram]
d1:Traction
Detector
m1:Brake
Modulator
c1:modulator
interface
Structure Behavior
Requirements Parametrics
act PreventLockup [Swimlane Diagram]
«allocate»
:TractionDetector
«allocate»
:BrakeModulator
allocatedTo
«connector»c1:modulatorInterface
DetectLossOf
Traction
Modulate
BrakingForce
TractionLoss:
allocatedFrom
«activity»DetectLos
OfTraction
d1:TractionDetector
allocatedFrom
«activity»Modulate
BrakingForce
m1:BrakeModulator
allocatedFrom
«ObjectNode»
TractionLoss:
c1:modulator
Interface
allocatedFrom
OfTraction
d1:TractionDetector
allocatedFrom
BrakingForce
m1:BrakeModulator
allocatedFrom
«ObjectNode»
TractionLoss:
c1:modulator
Interface
satisfies
«requirement»
Anti-Lock
Performance
allocatedFrom
Of Traction
d1:TractionDetector
values
DutyCycle: Percentage
allocatedFrom
BrakingForce
m1:BrakeModulator
allocatedFrom
«ObjectNode»
TractionLoss:
c1:modulator
Interface
satisfies
«requirement»
Anti-Lock
Performance
:Accelleration
Equation
[F = ma]
:VelocityEquation
[a = dv/dt]
:DistanceEquation
[v = dx/dt]
:BrakingForce
Equation
[f = (tf*bf)*(1-tl)]
tf: bf:tl:
f:
F:
m:
a:
a:
v:
v:
x:
v.Position:
v.Weight:
v.chassis.tire.
Friction:
v.brake.abs.m1.
DutyCycle:
v.brake.rotor.
BrakingForce:
:Accelleration
Equation
[F = ma]
:VelocityEquation
[a = dv/dt]
:DistanceEquation
[v = dx/dt]
:BrakingForce
Equation
[f = (tf*bf)*(1-tl)]
tf: bf:tl:
f:
F:
m:
a:
a:
v:
v:
x:
v.Position:
v.Weight:
v.chassis.tire.
Friction:
v.brake.abs.m1.
DutyCycle:
v.brake.rotor.
BrakingForce:
Braking Subsystem
Specification
Vehicle System
Specification
VerifiedBy
«interaction»MinimumStopp
ingDistance
id=“102”
«requirement»
StoppingDistance
SatisfiedBy
«block»Anti-LockController
id=”337"
«requirement»
«deriveReqt»
satisfy

Project activities using SysML
• Capture and analyze black box system requirements
– System Context & System Use Cases, Requirement Diagrams
• Develop one ore more candidate system architectures
– Block Definition & Internal Block Diagrams
• Perform engineering trade-off analysis to evaluate and
select the optimal architecture
– Parametric Diagrams
• Specify component requirements and their traceability to
system requirements
– Requirement diagrams
• Verify the system design by executing system-level test
cases

Perspectives for SysML
• Enable a common modeling language and
model across engineering disciplines
• Enable traceability between disciplines
• Enable different kinds of system analysis
• Enable integration of discrete and continuous
based modeling tools
• Critical enabler for Model Based System
Engineering with tool support

Summary
• SysML a common modeling language for different
disciplines e.g. Hardware, Software and Mechanics
• New and important concepts for cross disciplinary
analysis of system properties (e.g. parametric)
• Blocks and ports as general modeling elements
• Important enhancement to activity diagrams
• Lot of support for traceability between models and model
elements
• Must be supported by an appropriate Systems
Engineering (SE) process

References
• OMGs SysML homepage: www.omgsysml.org
• INCOSE organization: www.incose.org
• Books:
– ”A Practical Guide to SysML – The System Modeling Language”,
Sanford Friedenthal, Allan Moore, Rick Steiner, Elsevier, 2008.
– ”Systems Engineering with SysML/UML – Modeling, Analysis,
Design”, Tim Weilkiens, Elsevier, 2007.

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