SWE 760 Real-Time Software Design Lecture 6 –Dynamic ...

A-1

Copyright 2016 H. Gomaa

SWE 760 Real-Time Software Design

Lecture 6 – Dynamic Interaction Modeling for Real-Time Embedded Systems

Reference: H. Gomaa, Chapters 9 - Real-Time Software Design for Embedded Systems, Cambridge University Press, 2016

Hassan Gomaa

Dept of Computer ScienceGeorge Mason University

Fairfax, VA

Copyright © 2016 Hassan Gomaa

All rights reserved. No part of this document may be reproduced in any form or by any means, without the prior written permission of the author.

T

Copyright © 2016 Hassan Gomaa 2

Figure 4.1 COMET/RTE life cycle model

Requirements Modeling

Analysis Modeling

Incremental Software

Construction


Integration

System Testing

Incremental Prototyping

Customer

User

Design Modeling

System Structural Modeling

A-2


Analysis Modeling

• Static Modeling

– Define entity classes and relationships

• Dynamic State Machine Modeling

– Real-time systems are highly state dependent

– Actions depend on input event AND current state

• Object Structuring

– Determine objects that realize each use case

• Dynamic Interaction Modeling

– Determine sequence of interactions among objects

3

Copyright 2016 H. Gomaa4

Dynamic Interaction Modeling

• Use cases realized in Dynamic Model– Show objects participating in each use case

• Determine how objects participate in use case – Use object structuring criteria to determine objects

• Stereotype for each object structuring criterion– Shows sequence of object interactions in use case

• Depict on – communication diagram or – sequence diagram

• State dependent control objects– Modeled using statecharts

• Dynamic Modeling– Approach to determine how objects interact with each

other to support use case

A-3

Copyright 2016 H. Gomaadm-5

Dynamic Modeling

• Determine how objects interact with each other to support use case

– Start with external event from actor

– Determine objects needed to support use case

– Determine sequence of internal events following external event

– Depict on communication diagram or sequence diagram

• Stateless (non state-dependent) Dynamic Modeling

• State dependent Dynamic Modeling

Copyright 2016 H. Gomaadm-6

Stateless Dynamic Modeling

• Start with use case

• Determine boundary objects

– Receives external events from actor

• Determine internal objects

– Receive messages from boundary objects

• Determine object interactions

– Sequence of messages passed

• Develop main interaction sequence (scenario)

• Develop alternative sequences

– For alternative branches of use case

– E.g, for error handling or less frequently occurring conditions

A-4


Example of Stateless Dynamic Modeling

7

Timer

Send Vehicle Status

Driver

«timer actor»

(secondary actor)

Figure 9.4 Send Vehicle Status use case

(primary actor)

«human actor»



8

«external timer»: DigitalTimer

«timer»: VehicleTimer

«output»: VehicleDisplay

Output

«entity»: VehicleData

Driver

1: Timer Event

2: read(out location, out speed)

3: Vehicle Status

4: Vehicle Status

Fig 9.5: Sequence diagram for Send Vehicle Status use case

A-5



9


State Dependent Dynamic Modeling

• Object interaction controlled by statechart(s)

– Control object

• Executes statechart

• Activates/deactivates other objects

• For each use case

– Determine objects participating in use case

– Determine sequence of object communication

– Develop statechart for control object

• For each event that arrives at control object

– Determine state transition from current state to next state

– Determine actions and activities to be executed

– Determine objects required to perform actions and activities

A-6



«software system»«block»

LightRailControl System

«external input device»«block»

ArrivalSensor


ApproachingSensor


DepartureSensor


ProximitySensor


LocationSensor


SpeedSensor

«external output device»«block»

MotorActuator


DoorActuator


TrainDisplay


TrainAudioDevice


StationDisplay


StationAudioDevice

«external system»«block»

RailroadCrossingControl

«external user»«block»

RailOperator


DoorSensor

Interacts with

Outputs to

Outputs to

Outputs to

Outputs to

Outputs to

Outputs toInputs to

Inputs to

Inputs to

Inputs to

Inputs to

Inputs to

1..*

1..*

1..*

1..*

1..*

1..*

1..*

Inputs to

11

1

1

1

11 1

1

1

Communicateswith

11

1

1

1

1

1..*

1..*

1..*

1..*

1..*

1..*


WaysideMonitoringSystem

Communicateswith

1

1

Outputs to

1..*


RailOperationsDisplay

1..*1..*

Figure 21.3 Light Rail Control Software system context block diagram

A-7


ArrivalSensor

Control Train Operation

Control Train at StationArrive at Station Depart from Station

Departure Sensor

ApproachingSensor

DoorActuator

DoorSensor

Railroad Media

«include» «include» «include»

«use case package»LightRailOperations

Motor

Figure 21.4 Light Rail Control System actors and use cases: Light Rail Operations use case package


Control Train at StationArrive at Station Depart from Station

«include» «include» «include»


Suspend Train Dispatch Train

«use case package»TrainDispatchAnd

Suspend

«include»

DoorSensor

Rail Operator

Railroad Media

Door Actuator

Figure 21.5 Light Rail Control System: Train Dispatch and Suspend use case package

A-8


Arrive at Station Depart from Station

«extend» «extend» «extend»


Detect Hazard Presence Detect Hazard Removal

«use case package»RailroadHazardDetection

«extend»

ProximitySensor

Motor

Figure 21.6 Light Rail Control System: Railroad Hazard Detection


Cruising

Stopping

Entry / Open Doors

Doors Opening

Approaching

Entry / Send Approached

Stopped / Send Arrived

Approached/ Decelerate

Arrived/ Stop

Figure 21.9 State machine for Arrive at Station use case

A-9


Doors Closing

Entry / Open Doors

Doors Opening

Doors Open

Exit / Close Doors

Opened / Start Timer

After (Timeout) [All Clear] / Send Departing

Figure 21.10 State machine for Control Train at Station use case


Doors Closing

Cruising

Accelerating

Entry / Accelerate

Closed

Reached Cruising / Cruise

Figure 21.11 State machine for Depart from Station use case

Departed / Send Departed

A-10


Out of Service

Entry / Open Doors

Doors Opening

Doors Open

Exit / Close Doors


After(Timeout)[Suspending] / Send Out of Service

Figure 21.12 State machine for Suspend Train use case


A-11



A-12


Out of Service

Doors Closing

Cruising

Stopping

Emergency Halt

Hazard Detected

Hazard Removed [Not Approaching] / Send Hazard Removed

Hazard Detected

After(Timeout)[Hazard] / Start Timer

Entry / Open Doors

Doors Opening

Doors Open

Exit / Close Doors

Accelerating

Entry / Accelerate

Approaching


Emergency StoppingEntry / Emergency Stop, Send Hazard

DetectedHazard Detected

Hazard Removed [Approaching Station] / Accelerate Slowly, Send Hazard Removed

Hazard Removed [Approaching Station] / Accelerate Slowly, Send Hazard Removed

Dispatch / Send In Service




Closed





Arrived/ Stop

Hazard Removed [Not Approaching] / Send Hazard Removed

Stopped / Send Stopped

Figure 21.16 Flat state machine for Control Train



Out of Service

Doors Closing

Cruising

Stopping

Emergency Halt

Hazard Removed [Not Approaching]

Hazard Detected

After(Timeout)[Hazard] / Start Timer

Entry / Open Doors

Doors Opening

Doors Open

Exit / Close Doors

Accelerating

Entry / Accelerate

Approaching


Emergency StoppingEntry / Emergency Stop, Send Hazard

Detected

Hazard Removed [Approaching Station] / Accelerate Slowly

Dispatch / Send In Service




Closed





Arrived/ Stop

Stopped / Send Stopped

In Motion

Exit: Send Hazard Removed

Emergency

Figure 21.17 Hierarchical state machine for Control Train


A-13


«software system»«block»LightRailControlSystem«external input device»

«block»ArrivalSensor


ApproachingSensor


DepartureSensor


ProximitySensor


LocationSensor


SpeedSensor


MotorActuator


DoorActuator


TrainDisplay


TrainAudioDevice


StationDisplay


StationAudioDevice

«external user»«block»

RailOperator


DoorSensor

Interacts with

Outputs to

Outputs to

Outputs to

Outputs to

Outputs to

Outputs to

Inputs to

Inputs to

Inputs to

Inputs to

Inputs to

Inputs to

1..*

1..*

1..*

1..*

1..*

1..*

1..*

Inputs to

1

Communicateswith

1..*

1..*

1..*

1..*

1..*

1..*

Communicateswith

«user interaction»«subsystem»

RailOperationsInteraction

«service»«subsystem»

RailOperationsService

«control»«subsystem»TrainControlSubsystem

«output»«subsystem»

StationSubsystem

1

1

1

1

1

1

111

1

11111


RailOperationsDisplay

1 1

Outputs to

1..*


WaysideMonitoringSystem


RailroadCrossingControl 1..*

1..*

Figure 21.18 Light Rail Control Software subsystems


A-14


«output»«subsystem»:StationSubsystem

«output»«hwDevice»

StationAudio Device

Outputs to

«output»StationAudio

Output

«output»«hwDevice»

StationDisplay

Outputs to

«output»StationDisplay

Output

1

1

1

1

Figure 21.20 Input and output classes for Station Subsystem

«coordinator»Station

Coordinator

«entity»StationStatus


Dynamic Interaction Modeling of External Objects with Software System

• Starting with

– Use case model

– system context model

• From software system context diagram

– Model software system as one aggregate object

• Model instances of external objects from

– From use case model

• Follow sequence of interactions described in use case

• Depict interaction with external objects

28

A-15


1: Approach

2:Decelerate

3: Arrive

4: Stop

5: Stopped

6: Open Doors

7: Arrived

8: Arrived

«external input device»:Approaching

Sensor

«external input device»

:ArrivalSensor

«external output device»

:MotorActuator


:DoorActuator

«external input device»

:DoorSensor


:TrainDisplay


:TrainAudioDevice

«software system» :LightRailControl

System

Figure 21.21 Sequence diagram for Arrive at Station use case (external objects)


1: Approached

2: Decelerate

4: Send Approached

3: Decelerate

5: Arrived

6: Stop

7: Stop

8: Stopped

9: Stopped

10: Open Doors

11: Send Arrived

«state dependent control»:TrainControl

«input»:Door SensorInput

«output»:DoorActuatorOutput

«coordinator» :TrainStatusDispatcher

«ouput» :MotorOutput

«algorithm» :Speed

Adjustment

«input» :ArrivalSensorInput

«input» :ApproachingSensorInput

Figure 21.22 Sequence diagram for Arrive at Station use case (software objects)

A-16



A-17



A-18





Analysis Modeling


Construction


Integration

System Testing


Customer

User

Design Modeling


A-19


Analysis Modeling

• Static Modeling

– Define entity classes and relationships

• Dynamic State Machine Modeling

– Real-time systems are highly state dependent

– Actions depend on input event AND current state

• Object Structuring

– Determine objects that realize each use case

• Dynamic Interaction Modeling

– Determine sequence of interactions among objects

37




Analysis Modeling


Construction


Integration

System Testing


Customer

User

Design Modeling


SWE 760 Real-Time Software Design Lecture 6 –Dynamic ...

Documents

Transcript of SWE 760 Real-Time Software Design Lecture 6 –Dynamic ...