Dynamic Synthesis of Mediators in Pervasive Environments Amel Bennaceur supervised by Valérie...

Dynamic Synthesis of Mediators

in Pervasive EnvironmentsAmel Bennaceur supervised by Valérie Issarny

ARLES

14 February 2012, Junior Seminar, INRIA


14 February 20122

Outline

My team, my project, my thesis

Interoperability through dynamic synthesis of mediators

Reflections

My team, my project, my thesis

Interoperability through dynamic synthesis of mediators

Reflections


14 February 20123

Middleware for pervasive, distributed computing

System Architecture

My Team: ARLES

Software Architectures for Distributed Systems• enabling the pervasive computing/ambient intelligence vision

Qu

ality o

f Se

rvice

Intero

pera

bility

CONNECT Project

Multi-radio

Abstracting pervasive networks and resources

Leveraging highly dynamic and heterogeneous networking environments

System Models

Access and Interaction

Runtime Composition, Reconfiguration, and Adaptation

Discovery

Multi-device Multi-platform


14 February 20124

Illustrating the Interoperability Challenge

GMES: Global Monitoring for Environment & Security Discovery

What are the available services in vicinity?How can I communicate with other peers?What kind of data can I exchange with other peers?What kind of application can I use?Am I allowed to forward data to other peers?

, Interaction, Data , Application, NFP heterogeneity

Highly-dynamic and complex environments


14 February 20125

Existing Approaches to Interoperability

Changing systems

Change the system or attach an adaptor

Legacy systemsCode unavailable

×

System 2System1


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× Changing systems

Standardization

A chosen shared languageTanenbaum & Van Steen:

“the extent by which two implementations of systems from different manufacturers can co-exist and work together by merely relying on each other’s services as specified by a

common standard”

No one-size-fits all standard giventhe heterogeneity and complexity

of pervasive systems (and systems of systems)

×

System 2System1


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× Changing systems

× Standardization

Common Abstraction

One speaker talks the other’s language

Use an abstraction to design the component

Need to be aware a priori about all the possible configurations

×

System 2System1


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Babel fishTransform on the fly

using an intermediary system: the mediator

Can we observe, synthesize and deploy mediators dynamically?

Approaches to Interoperability

× Changing systems

× Standardization

× Common Abstraction

Mediation

System 2System1


14 February 20129

Thesis Statement

Systems with compatible functionalities should be able to interact despite heterogeneities in

their data and behavioral models.

Mediators that seamlessly overcome these heterogeneities should be dynamically

synthesized and deployed in their environment.


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Dynamic Mediation to Support Interoperability

Discovery

Modellevel

Systemlevel

→ Learning → Synthesis → Concretization → Monitoring

DownloadPhoto write PhotoFile

write PhotoMetadata

Model Extraction

Model Extraction

read PhotoFile

Mediator Model

downloadPhoto

read PhotoMetadata

Deployment

Monitor

Emergent Middleware

OntologyDownloadPhoto = getPhoto

Photo = PhotoMetadata + PhotoFilePhotoMetadata = PhotoID + Location + CameraID + details …

SynthesizeModeling

Synthesis

Deployment

write PhotoFile

write PhotoMetadata

System (NS2)

DownloadPhoto

System (NS1)


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Outline

My team, my project, my thesis Interoperability through dynamic synthesis

of connectors• Modeling• Synthesis• Deployment

Reflections


14 February 201212

Ontology-based Networked System Model

Ontology-based Functional Semantics• Affordance

• The high-level functionality of a system• e.g., <Req, PhotoSharing, Preferences, Photo>

• Interface• A set of observable actions• e.g., <SendSOAPRequest, DownloadPhoto,

{CameraID}, >

LTS-based Behavioural semantics• The way the observable actions are coordinated• At both application and middleware layers

• Application → Business logic• Middleware → Communication & coordination protocol

Interface

Networked System

Affordance Behaviour1

0..n

1

Ontologies

<SendSOAPRequest, DownloadPhoto,{CameraID}, >

<ReceiveSOAPResponse, DownloadPhoto, , {Photo}>


14 February 2012

Emergent Middleware Synthesis Informed by Ontologies

System (NS2)FunctionalMatchingSystem (NS1)

Ontologies

Does it make sense for NS1 and NS2 to interact?

13


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Functional Matching

System 2System1

AffC2 = <Req, PhotoSharing, {CameraID}, {PhotoFile}>

AffDrone = <Prov, PhotoSharing, , {Photo}>

What is the relation between a PhotoFile and Photo ?


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Domain-specific Ontology

Subsumption (is-a)


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Functional Matching

System 2System1

AffC2 = <Req, PhotoSharing, {CameraID}, {PhotoFile}>

AffDrone = <Prov, PhotoSharing, , {Photo}>

There is a functional matching between AffC2 and AffDrone

CameraID subsumes (co-variant) Photo subsumes a PhotoFile (contra-variant)


14 February 2012


Middleware Abstraction Middleware Abstraction

System (NS2)FunctionalMatching

Yes

System (NS1)

Middleware-agnostic Networked System (NS2)

Middleware-agnostic System (NS1)

Ontologies

Abstract from the communication protocol details and concentrate on

application semantics

17


14 February 2012

Middleware Ontology

18


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Middleware Abstraction

<SendSOAPRequest, DownloadPhoto,{CameraID}, >

<ReceiveSOAPResponse, DownloadPhoto,{Photo} >

<DownloadPhoto,{CameraID}, {Photo}>

C2 BehaviorC2 Middleware-agnostic

Behavior


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Middleware Abstraction

Drone BehaviorDroneMiddleware-agnostic

Behavior

<write, PhotoMetaData, , {photometadata}>

<write, PhotoFile, , {photofile}>

<PhotoMetaData, , {photometadata}>

<PhotoFile, , {photofile}>


14 February 2012




Yes

System (NS1)



Ontologies

21

Generate Mapping Processes

Mapping Processes

What are the translations that need to be performed?


14 February 201222

Generating Mapping Processes

Drone InterfaceC2 Interface

<DownloadPhoto,{CameraID}, {Photo}> <PhotoMetaData, , {photometadata}><PhotoFile, , {photofile}>

DownloadPhotoPhotoMetaData PhotoFile

1 - Define the constraints that need to hold between compatible actions

2- Use constraint programming to find possible mapping between interfaces<DownloadPhoto,{CameraID}, {Photo}>⟼<<PhotoMetaData, , {photometadata}>, <PhotoFile, , {photofile}>>

e.g., photo sumsumed by photometadata union photofile

3- Generate the corresponding mapping process


14 February 2012



CompatiblePartially compatible

Not compatible

Behavioral Matching


Yes

System (NS1)



Ontologies

23


Mapping Processes

Relies on ontology-based model checking to generate the model of the mediator that ensures their behavioral

interoperability


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Behavioral Matching

PhotoMetaData

PhotoFile

PhotoMetaData

PhotoFile

DownloadPhoto

DownloadPhoto

Drone BehaviorC2 Behavior Mediator Behavior


14 February 2012



CompatiblePartially compatible

Not compatible

Behavioral Matching


Yes

System (NS1)



Ontologies

25


Mapping Processes

DeploymentEmergent

Middleware

Refines the mediator model into a concrete software artifact: an emergent middleware

Failure


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Deployment (1)

Refine the mapping processes using middleware semantics

<ReceiveCall, DownloadPhoto, {cameraID}, >

<Read, PhotoMetadata,{cameraID}, {photometadata}>

<Reply, DownloadPhoto, , {photoFile}>

<Read, PhotoFile,{photoID}, {photoFile}>

PhotoMetaData

PhotoFile

DownloadPhoto

Get photoID from photoMetadata

Middleware& Domain-specific

Ontologies


14 February 201227

Deployment (2)

Listener 2

Actuator 2

Listener 1

Actuator 1

Emergent Middleware

Mediator

System 2System1


14 February 2012

Overall Reflections (1)

Interoperability remains a fundamental problem in the complex distributed systems of today

Dynamic synthesis of mediators offers promise in addressing interoperability in a future-proof manner

Ontologies have a key role to play in supporting synthesis: both application and middleware

28


14 February 2012

Overall Reflections (2)

Ontologies• Availability, characteristics, fuzziness• Heterogeneity in ontologies, alignment

Emergent middleware• Learning, dependability, exception handling• Evolution and incremental synthesis

User in the loop• The role of end users and experts in adaptation

29


14 February 2012

Thank you


14 February 201231

Further Information

Home page: www-rocq.inria.fr/~bennaceu ARLES: www.rocq.inria.fr/arles/ Connect: connect-forever.eu/

The Role of Ontologies in Emergent Middleware: Supporting Interoperability in Complex Distributed Systems, In Proc. Middleware 2011

Middleware-layer Connector Synthesis: Beyond State of the Art in Middleware Interoperability, In SFM 2011

Towards an architecture for runtime interoperability, In Proc. ISoLA 2010

Dynamic Synthesis of Mediators in Pervasive Environments Amel Bennaceur supervised by Valérie...

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