1. Dynamic Synthesis of Mediators
to Support Interoperability in
Autonomic Systems
Amel Bennaceur and Valérie Issarny
ARLES project-team
Inria Paris-Rocquencourt
NII-Shonan Workshop: Engineering Autonomic Systems (EASy)

2. Interoperability in Autonomic
Systems
 Systems are becoming increasingly connected
• Future Internet, Cyber-Physical System, Internet of Things
• Integration becoming more difficult
 Interactions among components cannot be planned
beforehand
• Increasingly dynamic
• Unanticipated components
 System and its components figure out how to interact at
runtime
• Automatically ensuring interoperation at runtime

3. Our Research on Interoperability
 Sustaining composition in highly heterogeneous
and dynamic environments
• Multi-* networking environments with heterogeneity at
all layers (application, middleware)
• Semantics of networked systems needed to reason
about and achieve on-the-fly interoperability
• Ontology for the description of functional
semantics
• LTSs for the description of behavioural semantics
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4. Illustrating the Interoperability
Challenges
 GMES: Global Monitoring for Environment & Security
 Discovery, Interaction , Data , Application, NFP heterogeneity
What kindcandata available services inuse? peers?
Am I What kindcan I exchange othervicinity?
What are Ithetoof application to other peers?
How of communicate with with other
allowed forward data can I peers?
Highly-dynamic and complex environments
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5. Existing Approaches to
Interoperability
× Change the system × A chosen shared × Use a common abstraction
or attach an adaptor language
Legacy systems No one-size-fits-all Need to be aware about all the
No runtime support standard possible configurations beforhand
Can we  an intermediary system:
Transform on the fly using
observe, synthesize and deploy mediators
dynamically?
the mediator
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6. Dynamic Mediation to Support
Interoperability
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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7. Dynamic Mediation to Support
Interoperability
Discovery → Learning → Synthesis → Concretization → Monitoring
Ontolog
y
DownloadPhoto = getPhoto
Photo = PhotoMetadata + PhotoFile
PhotoMetadata = PhotoID + Location + CameraID + details …
Synthesis
Mediator Model write PhotoMetadata
DownloadPhoto read PhotoMetadata
Model write PhotoFile
downloadPhoto read PhotoFile
level
Model Model
Extraction Deployment Extraction
System (NS1) System (NS2)
System write PhotoMetadata
level DownloadPhoto
Emergent
Middleware write PhotoFile
Monitor

8. Ontology-based Networked System
Model
 Ontology-based Functional Semantics 1 Networked
• Affordance System
• The high-level functionality of a system <SendSOAPRequest,
0..n
• e.g., <Req, PhotoSharing, Preferences, Photo> DownloadPhoto,{CameraID}, >
• Interface Interface Affordance
1
<ReceiveSOAPResponse, Behaviour
• A set of observable actions DownloadPhoto,  {Photo}>
,
• e.g., <SendSOAPRequest, DownloadPhoto,
{CameraID}, >
 LTS-based Behavioural semantics
• The way the observable actions are coordinated Ontologies
• At both application and middleware layers
• Application → Business logic
• Middleware → Communication & coordination protocol
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9. Emergent Middleware Synthesis
Informed by Ontologies
NS1 Model Ontologies NS2 Model
Thing
Affordance a d Affordance
B ir A <Prov, B, IB,OB>
<Req, A, IA,OA> ia
Interface Nothing Interface
δ1 = <SOAPCall, d, id, od>
α1 = <rd, a, ia, oa> λ1 = <SOAPCall, l, il, ol>
β1 = <out, b, ib, ob> ρ1 = <SOAPCall, r, ir, or>
Functional Behaviour
Behaviour
Matching t3
t2 !δ 1
?β 1 ?ρ 1
!α 1
!δ 1 ?δ 2
!ρ 2
?α 2 !β 2 ?λ 1
t4
t1
Does it make sense for NS1 and NS2
to interact?

10. Emergent Middleware Synthesis
Informed by Ontologies
Ontologies
NS1 Model Thing
NS2 Model
a d
Affordance B ir A Affordance
ia
<Req, A, IA,OA> <Prov, B, IB,OB>
Nothing
Interface Interface
δ1 = <SOAPCall, d, id, od>
α1 = <rd, a, ia, oa> λ1 = <SOAPCall, l, il, ol>
Middleware
β1 = <out, b, ib, ob> Abstraction ρ1 = <SOAPCall, r, ir, or>
Behaviour
Behaviour
t3
t2 !δ 1
?β 1 ?ρ 1
!α 1
!δ 1 ?δ 2
!ρ 2
?α 2 !β 2 ?λ 1
t4
t1
Abstract from the communication
protocol details and concentrate on
application semantics

11. Emergent Middleware Synthesis
Informed by Ontologies
Ontologies
NS1 Model Thing NS2 Model
a d
Affordance B ir A Affordance
ia
<Req, A, IA,OA> <Prov, B, IB,OB>
Nothing
Interface Interface
α = <a, ia, oa> δ = <d, id, od>
λ = <l, il, ol>
β = <b, ib, ob> Ontology-based
Action Mapping ρ = <r, ir, or>
Behaviour Behaviour
α' = < α , <δ, λ> > δ
α β β' = < β , <ρ> > ρ λ
…. ρ δ
α
What are the translations that need to
be performed?

12. Emergent Middleware Synthesis
Informed by Ontologies
NS1 Model α' = < α , <δ, λ> > NS2 Model
β' = < β , <ρ> >
Affordance …. Affordance
<Req, A, IA,OA> <Prov, B, IB,OB>
Interface Interface
α = <a, ia, oa> Behavioral δ = <d, id, od>
Matching & Synthesis λ = <l, il, ol>
β = <b, ib, ob>
ρ = <r, ir, or>
Behaviour Behaviour
Success
δ
α β ρ
Abstract CONNECTor Model λ
ρ δ
α δ
ρ λ
α
β
Select the appropriate mapping processes
and compose them such that both
systems reach their final states

13. Emergent Middleware Synthesis
Informed by Ontologies
Ontologies
Thing
NS1 Model a d NS2 Model
B ir A
Affordance ia Affordance
Nothing
<Req, A, IA,OA> <Prov, B, IB,OB>
Abstract CONNECTor Model
Interface Interface
ρ δ δ = <d, id, od>
α = <a, ia, oa> λ
λ = <l, il, ol>
β = <b, ib, ob> α
β ρ = <r, ir, or>
Behaviour Behaviour
δ
α β Concretization
ρ λ
ρ δ
α Concrete CONNECTor Model
t2 t3 !δ 1
!ρ 1 ?β 1 ?α 1
?δ 2
?ρ 2 !β 2 !α 2 ?λ 1
t1 t4
Refines the mediator model into a
concrete software artifact:
an emergent middleware

14. Approach In Action:
Domain-specific Ontology
PhotoSharing
PhotoSharingProducer
PhotoSharingProducer PhotoSharingServer
PhotoSharingServer PhotoSharingConsumer
PhotoSharingConsumer
Photo
Subsumption (is-a)
PhotoMetadata PhotoFile
PhotoID: string
CameraID: string
Longitude: double
Latitude: double
Resolution: integer
Information:string
SearchPhoto DownloadPhoto UploadPhoto
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15. Approach In Action:
Functional Matching
System1 System 2
AffC2 = <Req, PhotoSharing, AffDrone = <Prov, PhotoSharing,
{CameraID}, {PhotoFile}>  {Photo}>
,
CameraID subsumes  (co-variant)
Photo subsumes a PhotoFile (contra-variant)
There is a functional matching between AffC2 and AffDrone
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16. Approach In Action:
Middleware Ontology
RemoteProcedureCallAPI
RemoteProcedureCallAPI
SendSOAPRqt ReceiveSOAPResp ReceiveSOAPRqt SendSOAPResp
0..1 +
0..1 + follows {some} 0..1 + follows {some}
0..1 + follows {some}
Call ReceiveReply
ReceveReply ReceiveCall Reply
+hasOutput {some}
+hasInput {some} +hasInput {some}
+hasOutput {some}
MethodName
MethodName Arguments
Arguments ReturnValue
ReturnValue
+hasInput {some} +hasOutput {some}
SOAPRequest SOAPResponse
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17. Approach In Action:
Middleware Abstraction
C2 Middleware-agnostic
C2 Behavior
Behavior
<SendSOAPRequest,
DownloadPhoto,{CameraID}, > <DownloadPhoto,{CameraID}, {Photo}>
<ReceiveSOAPResponse,
DownloadPhoto,{Photo} >
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18. Approach In Action:
Middleware Abstraction
DroneMiddleware-agnostic
Drone Behavior
Behavior
<write, PhotoMetaData, ,
{photometadata}> <PhotoMetaData, , {photometadata}>
<write,
PhotoFile, , {photofile}> <PhotoFile, , {photofile}>
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19. Approach In Action:
Generating Mapping Processes
C2 Interface Drone Interface
<DownloadPhoto,{CameraID}, {Photo}> <PhotoMetaData, , {photometadata}>
<PhotoFile, , {photofile}>
1 - Define the constraints that need to hold between compatible actions
e.g., photo sumsumed by photometadata union photofile
2- Use constraint programming to find possible mapping between interfaces
<DownloadPhoto,{CameraID}, {Photo}>⟼
<<PhotoMetaData, , {photometadata}>, <PhotoFile, , {photofile}>>
3- Generate the corresponding mapping process
PhotoMetaData PhotoFile DownloadPhoto
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20. Approach In Action:
Behavioral Matching
C2 Behavior Mediator Behavior Drone Behavior
PhotoMetaData
PhotoMetaData
DownloadPhoto
PhotoFile
PhotoFile
DownloadPhoto
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21. Approach In Action:
Deployment
<receiveCall, DownloadPhoto,
{cameraID},  >
 Refine the mapping
PhotoMetaData
processes using
<read, PhotoMetadata,
middleware semantics {cameraID}, {photometadata}>
PhotoFile
Get photoID from photoMetadata
<read, PhotoFile,
{photoID}, {photoFile}>
DownloadPhoto
Middleware <reply, DownloadPhoto,
 {photoFile}>
,
& Domain-specific
Ontologies
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22. Approach In Action:
Deployment
System1 Emergent Middleware System 2
Parser 1 Mediator Composer 2
Composer
1
Parser 2

23. Open Issues
 Learning is (almost) always partial
 Evolution and incremental synthesis
Discovery
New NSs
Learning
Evolution of the
NS Model
Monitoring (re)Synthesis
Synthesis
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24. Open Issues In CONNECT
 Enforcing the goal instead of achieving it
 Ontologies
• Processing overhead, fuzziness, learning,
heterogeneity in ontologies, alignment

25. Summary
 Interoperability remains a fundamental
problem in today’s complex systems
 Dynamic synthesis of mediators promises
to address interoperability in a future-proof
manner
Still..
 Need to make complete the NS model and
re(synthesize) mediators incrementally
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26. Thank you

27. 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
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