This document summarizes the Coast research team which studies web-scale collaborative systems. It outlines the team composition, research directions including collaborative data management, data-centered service composition, and trustworthy collaborative systems. It then provides more details on specific projects related to each research direction, including a new optimistic replication algorithm, the impact of delays on collaboration, distributing service composition, and a model for computational trust in collaborative systems. Future work is also mentioned including the OpenPaaS::NG platform and studies on maintaining trust in distributed collaboration without central authorities.

1. Coast
Web Scale Trustworthy Collaborative Information
Systems
Est. July 2015
EQUIPE PROJET
Coast
CENTRE Inria
Nancy Grand Est

2. Team composition
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9 Permanent members
• Khalid Benali (Associate Professor HdR, Univ Lorraine)
• Gérôme Canals (Associate Professor, Univ Lorraine)
• François Charoy (Professor, Univ Lorraine– Team Leader)
• Claude Godart (Professor, Univ Lorraine )
• Claudia Ignat (Researcher, Inria)
• Gérald Oster (Associate professor, Univ Lorraine)
• Olivier Perrin (Professor, Univ Lorraine )
• Pascal Urso (Associate professor, Univ Lorraine)
• Samir Youcef (Associate professor, Univ Lorraine)
7 PhD Students – 1 Postdocs – 2 Engineers

3. Research Directions
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Web Scale Collaborative systems :
Supports collaboration between people and services at the
scale of the Web
Topics :
• Collaborative Data Management
• Data centered Service composition
• Trustworthy Collaborative Systems

4. Building a modern web application
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5. Web scale problems
> 5 000 000 rooms
> 1000 renting platforms
> 100 countries
Manage
contract
Intermediation
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6. Web scale data replication
Replicated calendar
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7. EPC Coast project background
• Previous Score and ECOO goals
– Collaboration,
– Service Orchestration and BPM
– Optimistic Replication
• Now with
– Web Scale and Trust
– Considering User Experience
– Validating reproducible experimentation
Ecoo
-2010
Score
2010-
2014
Coast
2014
Coast
EPC
7/2015
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8. Three research topics
Collaborative data
Management
Data centered service
composition
Trustworthy
collaborative systems
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9. Collaborative Data Management
Claudia Ignat, Gérald Oster, Pascal Urso, Gérome
Canals
ANR Streams, ANR Concordant, FP7 Syncfree
OpenPaaS::NG, TVPaint

10. Collaborative Data Management
Research objectives
• Find new algorithms for optimistic replication in the context of
collaboration
• Study the impact of usage on performances
Methods
• Algorithm design and analysis
• Experimentation with users
• Simulation with real collaboration data
Applications
• Collaborative editing
• File Sharing
• Software Development
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11. New optimistic replication algorithm : LogootSplit
Conflict-free Replicated Data Types (CRDT)
• Consider strings rather than characters
• Ensure convergence of replicas
• Suitable for large scale collaborative editing
André, L. et al. 2013 “Supporting Adaptable Granularity of Changes for Massive Scale Collaborative Editing”
CollaborateCom 2013
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12. Propagation Delay impact on Group Performance
• Delay :
• increases error rate and redundancy in collaborative note taking
Figure 3
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KeywordProportion
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Word Count at 15min Keyword Proportion
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Redundancies
ErrorRate
Delay Condition (sec)
Error Rate Redundancies
Google doc performances vs
Number of users
Claudia-Lavinia Ignat, et al.. How Do User Groups Cope with Delay in Real-Time Collaborative Note Taking.
European Conference on Computer Supported Cooperative Work 2015, Sep 2015, Oslo, Norway, pp.223-242, 2015
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13. Data Centered Service Composition
Claude Godart, Francois Charoy, Samir Youcef,
Khalid Benali, Olivier Perrin
Groupe Open – Bonitasoft - OpenPaaS

14. Data Centered Service composition
• Research objectives
• tools and methods for safe composition of services
• Decentralized orchestration of services
• Efficient use of resources for composition execution
• Methods
• Propose, validate and experiment models
• for composition and execution distribution
• for efficient process deployment in the cloud
• Applications
• Inter enterprise collaboration
• Business Information Systems
• Crisis management
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15. Distribution and obfuscation of service
composition
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• Distribute service composition in the cloud
• Hide know how from partners
• Equivalence of the decomposition
• Difficult to infer the original process
Elio Goettelmann et al.. Paving the Way towards Semi-automatic Design-Time Business Process Model Obfuscation. IEEE ICWS 2015,

16. Elastic BPM as a Service in the Cloud
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• Ensure BPM execution QoS
under an evolving load
• Hourly adjustment of resources
and migration of tenants
• Minimize Cost and Minimise
tenant migrations
• Heuristic design and
experimentation
Simulation on AWS
Guillaume Rosinosky et Al. An Efficient Approach for Multi-tenant Elastic Business Processes Management in Cloud Computing
environment.- IEEE Cloud 2016,
Price of configurations
Best solution vs heurisitic

17. Trustworthy collaborative systems
Claudia Ignat, François Charoy, Gérald Oster, Olivier
Perrin
OpenPaaS, OpenPaaS::NG
USCoast 2, LUE Digital trust

18. Trustworthy collaborative systems
• Research Objectives
• Validate trust model computed on collaborative experience
• Deploy security and trust protocol in a p2p collaborative
setting
• Methods
• Test hypothesis about trust on users
• Implement and deploy in p2p collaborative systems
• Experiment systems with users
• Applications
• Inter-organisational collaboration
• Large scale service composition
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19. Security in Entreprise Social Network
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Inter-organisational access control
• No central authority
• Policy-based model in event calculus
Security Governance
• dynamic evaluation of ESN actors’ trust levels,
• risk assessment mechanism on the top of the access control decisions
Ahmed Bouchami, Olivier Perrin, Ehtesham Zahoor. Trust-Based Formal Delegation Framework for Enterprise Social Networks. IEEE TrustCom-15
Ahmed Bouchami, et al. Enhancing Access-Control with Risk-Metrics for Collaboration on Social Cloud-Platforms.TrustCom-BigDataSE-ISPA 2015,.

20. A model of trust-based collaboration
• New trust metric
• For a round:
• aggregation
• deals with fluctuating user
behavior
• Better to predict behavior
that other similar metrics
aggregate_trustt =at *current_trustt +(1-at )*aggregate_trustt-1
Quang-Vinh Dang, Claudia-Lavinia Ignat. Computational Trust Model for Repeated Trust Games. IEEE TrustCom-16
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21. Future Work
OpenPaaS::NG
Groupe Open
USCoast2
LUE Digital Trust

22. OpenPaaS::NG: P2P Collaborative platform
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Merging Enterprise Social Network and Collaboration services
Companies : Linagora, Xwiki, Nexedi,
Labs : DaSciM (LiX), Coast (Inria/LORIA)
• PIA PSPC 2014
• 4 years (2015-2019)
• Total cost : 20 M€
• Coast funding 1 M€
- 4 PhD
- 60 months Postdocs
- 72 months Engineers

23. Inter-disciplinarity – User experiment
• Get a better understanding of
• User trust in collaborative systems
• Mechanisms that impact trust
• Adjust systems to better align
• Risk perceived vs actual risk
• Wright State University Psychology Department and Knoesis
• USCoast 2 Inria Associate team
• Université de Lorraine Psychology Department
• Lorraine Université d’excellence PhD funding
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24. On going work
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• How to maintain trust
• For community
collaboration
• Without central authority
• Requires
• Constraints over p2p
replication
• Contract based service
composition and
monitoring

25. Federated Collaboration
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Sharing among organisations without a managing partner
Keep control of sharing between pairs
Inter-organisation

26. Multi-Organisation collaboration
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Ultimately
remove the need
for intermediation
platforms
Web Scale

27. Thank you
www.inria.fr