Capturing Variability in Space and Time

VICCIVisual and Interactive Cyber-Physical Systems Control and Integration

Capturing Variability in Space and Timewith Hyper Feature Models

Christoph SeidlIna SchaeferUwe Aßmann

Variability in Space and Time with Hyper Feature Models - Seidl, Schaefer, Aßmann 2

Background Software Ecosystems (SECOs) and Variability Formalization of Feature Models

Problem: No Variability in Time in Feature Models

Contributions Hyper Feature Models (HFMs) Version-Aware Constraint Language Automatic Version Selection

Conclusion: Capturing Variability in Space and Time with HFMs

Agenda

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Software Ecosystems (SECOs) Family of closely related software systems E.g., Eclipse, Android, ROS etc. Similar to SPLs, but…

Multiple contributors Frequent (unsynchronized) evolution of variable assets

Background

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Variability in Space Configuration Variant of system

Variability in Time Evolution Version of system

Variability in Space and Time with Hyper Feature Models - Seidl, Schaefer, Aßmann

Running Example: TurtleBot Driver

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UltrasoundInfraredBump

[1..3]

DetectionWebservice

AutonomousGamepadKeyboard

[1..1]

MovementEngine

TurtleBot

Cross-Tree Constraints1. Autonomous ® Detection2. Keyboard Ú Gamepad ® Webservice


DetectionWebserviceMovementEngine

Definition 1: Feature Model

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[1..3]


[1..1]

TurtleBot[0..1][1..1]

Cross-Tree Constraints1. Autonomous ® Detection2. Keyboard Ú Gamepad ®

Webservice


Cross-Tree Constraints1. Autonomous ® Detection2. Keyboard Ú Gamepad ®

Webservice

Definition 2: Feature Model Semantics

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[1..3]


[1..1]

TurtleBot


Problem: No Variability in Time in Feature Models

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[1..3]

DetectionWebservice


[1..1]

MovementEngine

TurtleBot

Constraints caused by evolution (excerpt) iClebo Kobuki is incompatible with TurtleBot v1.0 iClebo Kobuki requires at least TurtleBot v2.0

Problem Feature model captures only variability in space Only exactly one version of variable asset in feature

model (no variability in time)

iRobot Create iClebo Kobuki v1.0 v2.0Evolution!Evolution!


Requirement 1Support for feature versions as units of configuration.

Requirement 2Specification of the relation of versions in logical development lines (i.e., predecessor and successor versions including branching).

Requirement 3Expression of dependencies on and incompatibilities with version ranges.

Requirement 4Support for users in selecting suitable combinations of versions from a selection of features.

Requirements on Solution

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Hyper Feature Models (HFMs)Contribution 1


Definition 3: Hyper Feature Model (HFM)TurtleBot

1.01.1

2.12.0


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[1..3]


[1..1]

TurtleBot

1.00.90.8

Requirement 1

Requirement 2b

Feat

ure

Mod

el(D

efini

tion

1) Requirement 2a


Definition 5: HFM Semantics

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Ultrasound

1.00.90.8

Infrared

2.22.01.0

Bump

1.0

Autonomous

2.01.11.0

Gamepad

2.01.0

[1..1]

Movement

1.0 2.01.21.1

Engine

Create 1.21.0

Kobuki 1.01.1

TurtleBot

1.01.1

2.12.0

[1..3]

Detection

1.11.0

Webservice

1.11.0

1.0

Keyboard


Definition 5: HFM Semantics

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1.0

Create 1.21.0

Kobuki 1.01.1

1.0 2.01.21.1

1.01.1

2.12.0

Feat

ure

Mod

el(D

efini

tion

2)

Keyboard

MovementEngine

TurtleBot

Version-Aware Constraint LanguageContribution 2


Definition 6: Version-Aware Constraint Syntax

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Com

poun

d Ex

pres

sion

sAt

omic

Ex

pres

sion

s

Bool

ean

Alge

bra

Requirement 3


f [va – vb]?f [va – vb] º (f ® f [va – vb])

Examples TurtleBot [1.0 – 1.1] ® Engine [£ Create 1.2] ?Movement [1.2 – 2.0]

Semantics

Usage Closed intervals (fixed even if evolved) E.g., dependencies of Eclipse manifest files

(Conditional) Version Range Restrictions

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1.01.1

2.12.0

TurtleBot

TurtleBot [1.0 – 1.1]


f [op va]?f [op va] º (f ® f [op va])

Operators: op = {>, ³, =, £, <}

Examples TurtleBot [1.0 – 1.1] ® Engine [£ Create 1.2] ?Engine [³ Kobuki 1.0]

Semantics

Usage No need to know all versions in the interval explicitly Open intervals (extended in case of evolution)

(Conditional) Relative Version Restrictions

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1.01.1

2.12.0

TurtleBot

TurtleBot [£ 2.1]

Automatic Version SelectionContribution 3


Automatic Version Selection: General Procedure

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+

encode

1.11.0

Ultrasound

1.00.90.8

Infrared

2.22.01.0

Bump

1.0

Autonomous

2.01.11.0

Gamepad

2.01.0

Keyboard

[1..1]

Movement

1.0 2.01.21.1

Engine

Create 1.21.0

Kobuki 1.01.1

TurtleBot

1.01.1

2.12.0

[1..3]

Detection

1.11.0

Webservice

1.0

1.11.0

1.00.90.82.22.01.01.02.01.11.02.01.0

[1..1]

1.0 2.01.21.1Create 1.21.0

Kobuki 1.01.1

1.01.1

2.12.0

[1..3]

1.11.0

1.0

UltrasoundInfraredBumpAutonomousGamepadKeyboard

MovementEngine

TurtleBot

DetectionWebservice

Version-Aware Constraints1. Autonomous ® Detection2. Keyboard Ú Gamepad ® Webservice3. Infrared [³ 2.0] Ú Ultrasound ® Detection [³

1.1]4. TurtleBot [³ 2.0] ® Engine [³ Kobuki 1.0]5. TurtleBot [1.0 – 1.1] ® Engine [£ Create 1.2]6. TurtleBot [³ 2.0] ® ?Webservice [³ 1.1]

Constraint Satisfaction Problem (CSP) Solver

All Possible (Version) Configurations

select

solve

Scoring to find "best" configuration


i(v) = 1/(0 + 1) = 1.0n(v) = 1/(0 + 1) = 1.0s(v) = i(v) * n(v) = 1.0

i(v) = 1/(0 + 1) = 1.0n(v) = 1/(0 + 1) = 1.0s(v) = i(v) * n(v) = 1.0

1.11.0

Scoring to Find "Best" Configuration

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Ultrasound

1.00.90.8

Infrared

2.22.01.01.0

Autonomous

2.01.11.0

Gamepad

2.01.0

[1..1]1.0 2.01.21.1Create 1.2

1.0Kobuki 1.0

1.1

1.01.1

2.12.0

[1..3]1.11.0

1.0

Requirement 4 importance(v) = 1/(0 + 1) = 1.0novelty(v) = 1/(1 + 1) = 0.5score(v) = i(v) * n(v) = 0.5

BumpKeyboard

MovementEngine

TurtleBot

DetectionWebservice

i(v) = 1/(1 + 1) = 0.5n(v) = 1/(0 + 1) = 1.0s(v) = i(v) * n(v) = 0.5

TurtleBot [³ 2.0] ® Engine [³ Kobuki 1.0]

i(v) = 1/(1 + 1) = 0.5n(v) = 1/(0 + 1) = 1.0s(v) = i(v) * n(v) = 0.5


Problem: No variability in time in Feature Models

Solution Hyper Feature Models (HFMs) Version-Aware Constraint Language Automatic Version Selection

Fulfills initially posed requirements Evaluated in case study using TurtleBot driver

Capturing variability in space and time in Hyper Feature Models

Conclusion

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Questions, Comments, Feedback?Thank you for your attention!

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Capturing Variability in Space and Time