Executable Models Model Verification & Validation

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Executable Models

Model Verification & Validation

Fazilat Hojaji

June 2019

Model-Driven Software Engineering Research Group

Faculty of Computer Engineering

Department of Software Engineering

University of Isfahan

mdse.ui.ac.ir

Workshop on Model-Based Design, Test, and Verification of Software

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Overview

1. Executable Model: What & Why?

2. Executable Modeling Languages

3. Example: PetriNet

4. Model Validation & Verification (V&V)

5. V&V Tools

6. Demos


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Software Development Lifecycle


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What is Executable Model?


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Traditional Modeling is Extra WorkHow it usually works without executable models

But…

• It is hard to validate the correctness of the models before development.

• The developers may not follow the models, without providing feedback.

• It is hard to keep the models and development artifacts in sync during

development (and maintenance).


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Executable Modeling Just Works

Using a standards conforming UML

modeling tool

Using a standards conforming UML

execution tool

The models are the source codeWorkshop on Model-Based Design, Test, and Verification of Software

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System engineers create the models

System engineers analyze, simulate and validate the system design, and allocate requirements to components.

Using a standard conforming SysML

modeling tool

Models can include both hardware and

software components.

Execution artifacts could include: System

Behavior, Statistics

Agile Development…. with executable models

Executable Modeling Just WorksUsing a standard conforming SysML

modeling tool


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Executable Model Ecosystem


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What to Model?

Aspects to be modeled:

Static (Structural) Modeling

Dynamic (Behavioral) Modeling

Actions (Behavior in detail)

Concept Called Modeled As Expressed As

The world is full of

things

data Classes, Attributes,

Associations, Constraints

UML class diagram

Things have lifecycles control States, Events, Transitions

Procedures

UML state chart

diagram

Things do as each

stage

algorithm actions Action language

Concepts in UML executable models


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UML Executable Model


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Modeling Languages

UML executable models may be specified using

several modeling languages


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Executable Modeling Languages

Petri Nets

Finite State Automata

Examples

UML Activity Diagrams

UML State Machines

Executable modeling are used to define and execute models.


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Components of a modeling language

Syntax: Concepts provided for defining models

Formalism: Metamodeling languagesOMG MOF standard

EMF Ecore

Semantics: Meaning of the provided concepts

Modeling Language

Syntax Semantics

defines

meaning

Executable Modeling Languages: Components


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Executable Modeling Languages:Design & Implementation


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Executable Modeling Languages: Concrete Syntax

Example: Petri net

t1p1 p2

p3

p4t2

Place

Transition

Input place of

t1

Output place of

t1


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Net

Place

name : String

Transition

name : String

input *

output *

transitions* places*

InitialTokens: Int

Executable Modeling Languages: Abstract Syntax


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Executable Modeling Languages: Semantics


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Operational SemanticsDefines an interpreter for a modeling language

Components of operational semantics

Runtime concepts: Define the state of an executable model during execution Formalism: Metamodeling languages

Steps of computation: Define the transitions from one state of an executable model to the next state

Operational Semantics

Runtime

Concepts

Steps of

Computation


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Operational Semantics: Runtime Concepts

Example: Petri nets

Syntax Metamodel

Net

Place

name : String

Transition

name : String

input *

output *

transitions* places*

InitialTokens: Int

number of tokens of Place objects

changes during execution


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t1p1 p2

p3

p4t2

Initial

marking

Enabled

transition

Example: Petri nets Execution


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t1p1 p2

p3

p4t2



New

marking

Enabled

transition

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t1p1 p2

p3

p4t2



Final

marking

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Executable Models


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This is not a new idea…


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But it wasn’t standardized before…


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Foundational UML (fuml)is an OMG standard

is an executable sub-language of UML and can be used for defining operational semantics

Uses operational approach

Specification of behavioral semantics of foundational UML subset

Class modeling: class, association, data type, etc.

Activity modeling: activities, parameters, nodes, flows, etc.

Action language: communication, object, structural feature, link actions

Virtual machine implemented with Java for executing models


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Model Execution: Looking ahead…

Model

Edition & Consistency

Model

Composition

Model/System

Integration

Allocation & Deployment

Model

Model Execution &

Reconfiguration

Design-Space

Exploration

Data analysis, Model Discovery,

Execution trace analysis

Model

Validation & Verification

(Models at Design-time) (Models at Run-time)


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Summary

Executable models provide abstractions and enable early analyses of the behavior of a system

Executable modeling languages need to have well defined semantics

Operational semantics define runtime concepts (state information) and steps of computation (state transitions) for interpreting models

Foundational UML (fUML) is an executable sub-language of UML and can be used for defining operational semantics


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Dynamic ModelValidation & Verification


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Dynamic Verification & Validation

Debug Test

Model checking

Dynamic analysis

Runtime verification

Tracing

How can the quality of

executable models be improved?

Dynamic Verification and Validation (V&V) techniques are used to ensure the correctness of the modeled behavior


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Dynamic V&V: An example

Dynamic analysis uses execution traces to analyze the properties of a running system and to represent the system's actual behavior.

Execution traces are generated during the execution of a model, and provide information to help reason about the model's execution behavior.

Analysis Design Implementation Maintenance.....

Execution trace

defects\feedbacksverification

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Model Testing Validate whether a system meets functional requirements


• Model-based testing: Testing a system’s implementation

based on models

• Testing models: Test a system’s design defined by an

executable model

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Model Debugging

Locate defects in a system, e.g., model animation

Model-based debugging: debugging a running application with the help of a model

Debugging models : model modification at runtime, back stepping, step-wise execution, ...


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Stepwise Debugging (interactive debugging)

find the cause of a defect by manually observing and

controlling execution


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Omniscient Debugging

Stepwise debuggers only go forward

Omniscient debuggers go forward and backward

Omniscient debuggers rely on an execution trace storing previous steps


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Model Debugging & Model Animation


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Semantic Model Differencing

Models are subject to change Change management for models is required

Model differencing

Goal: Identify differences among models

Applications: Merging, versioning, conflict detection, incremental testing, etc.


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C

M1

M2

Model

Execution

l lM1 M2

T

T

M1

M2

Semantic

Matching

Match

Rules

Sem

CM1,M2

sem

CM1,M2

syn

M1

M2

Syntactic

Matching

Match

Rules

Syn

M1,M2

syn

T

T

M1

M2

Syntactic Differencing

Epsilon Comparison

Language (ECL)



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C

M1

M2

Model

Execution

l lM1 M2

T

T

M1

M2

Semantic

Matching

Match

Rules

Sem

CM1,M2

sem

CM1,M2

syn

M1

M2

Syntactic

Matching

Match

Rules

Syn

M1,M2

syn

T

T

M1

M2

Generic

Execution

Trace

Model Execution



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C

M1

M2

Model

Execution

l lM1 M2

T

T

M1

M2

Semantic

Matching

Match

Rules

Sem

CM1,M2

sem

CM1,M2

syn

M1

M2

Syntactic

Matching

Match

Rules

Syn

M1,M2

syn

T

T

M1

M2

Epsilon Comparison

Language (ECL)

Semantic Differencing



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Dynamic Analysis Analyze properties of a running program (model), e.g.,

Trace exploration for executable models

Trace visualization based on models

Non-functional property analysis: Analyze emergent properties of a system, e.g.,

Performance analysis


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Tools for Model Execution,

Verification &Validation


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Main Current Initiatives

MatlabSimulink, cf.

https://www.mathworks.com/products/simulink.html

LabView, cf. www.ni.com/labview

• xtUML https://xtuml.org/xtuml-days-2018copenhagen

• Blog post series by Leon Starr on modeling-languages.org: https://modeling-languages.com/author/leon-starr

• BridgePoint, cf. https://xtuml.org

UML-RT • Papyrus-RT: https://www.eclipse.org/papyrus-rts


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The Gemoc Studio

Designate and Integrate

your Executable DSL

Edit simulate and Animate

your heterogeneous models


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Metamodeling

Languages

Executable

Modeling

Languages

Executable

Models

The Gemoc Studio


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The GEMOC Community


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Conclusion

While modeling techniques are widely adopted in various guises (incl. behavioral modeling), model execution in still under used

Rethink our model execution tools to support

Immediate feedback (from the runtime state)

Direct manipulation (of the runtime state)

Reasoning over the time (on the runtime state)

Live modeling and time traveling should be at the core of model execution


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Tools Introduction & Demos


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UMPLEis a technology for model-oriented programming. It merges the concepts of programming and modeling by

adding modeling abstractions directly into programming languages

https://cruise.eecs.uottawa.ca/umple/

https://cruise.eecs.uottawa.ca/umpleonline/

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Umple Online

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Practice

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Papyrus Industry Consortium


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MOKA: Model Execution

is a Papyrus module for execution of UML models, which natively includes an execution engine complying with OMG standards


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Fuml Example: A Counter

Running the model using the

MOKA engine see 2min video

Moka is a Papyrus module for

execution of UML modelshttp://wiki.eclipse.org/Papyrus/UserGuide/Mod

elExecution#Moka_Overview


http://wiki.eclipse.org/Papyrus/UserGuide/ModelExecution#Moka_Overview

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The Cameo Simulation Toolkit provides the firstin the industry extendable model executionframework based on OMG fUML and W3CSCXML standards. It extends UPDM plugin tovalidate system behavior by executing,animating, and debugging SysML Parametricmodels in the context of realistic mock-ups ofthe intended user interface.

Cameo Simulation Toolkit


https://www.nomagic.com/product-addons/magicdraw-addons/cameo-simulation-toolkit

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Activity execution (OMG™ fUML standard)

State machine execution (W3C SCXML standard)

SysML parametric execution (OMG SysML standard)

Multiple action languages support (JSR223 standard)

Exporting UML state machine to SCXML file format

Full featured model debugger

Execution animation

Quick UI prototyping

Pluggable engines and evaluators

Model-driven test cases and scenarios

Cameo Simulation Toolkit: Features

Workshop on Model-Based Design, Test, and Verification of SoftwareWorkshop on Model-Based Design, Test, and Verification of Software

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Feature

Presentation

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References[1] J. Whittle, J. Hutchinson, and M. Rouncefield, “The State of Practice in ModelDriven Engineering,” IEEE Software, vol. 31, no. 3, 2014, pp. 79–85.

[2] T. Mayerhofer, Model Execution, presented in Business Informatics Group, 2014.

[3] Stephen J. Mellor and Marc J. Balcer, “Executable UML: A Foundation for Model-Driven Architecture,” Addison Wesley, 2002.

[4] Engineering ModelingLanguages: TurningDomain KnowledgeintoTools, by Benoit Combemale, Robert B. France, Jean-Marc Jézéquel, Bernhard Rumpe, Jim R.H. Steel, and Didier Vojtisek. Chapman and Hall/CRC, pp.398, 2016.

[5] Kermeta (http://www.kermeta.org/)

[6] Combemale, B., Crégut, X., Giacometti, J.-P., Michel, P., & Pantel, M. (2008). Introducing simulation and model animation in the mde topcasedtoolkit. Paper presented at the 4th European Congress Embedded Real Time Software (ERTS).


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THANK YOU!

ANY QUESTIONS?


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Executable Models Model Verification & Validation