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Un peu de recherche… LIRIS/DCS/DRIM 2 Nostalgia: an overview of the past 10 years • Some contributions to the management of data in grids • Some contributions to Pervasive/Ubiquitous Systems… and other distributed systems (incl. security and privacy) 3 Some contributions to the management of data in grids Computing/Data Grid (1) “coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organisations” (I. Foster) 5 Computing/Data Grids (2) • Large scale • Unpredictability, dynamicity • Security, privacy • Resource heterogeneity and usage diversity • Decentralized administration 6 Monitoring de grilles • • • • Where to place instances (replicas) of a service? What resource (set of resources) (what service) use? Condition: monitor the grid state: CPU load, network load… Design and implementation of a grid service that processes highlevel information requests that represent the user’s specific needs in terms of resources Temps de rapatriement 1,00E+08 1,00E+07 1,00E+06 1,00E+05 Réplica A Réplica B Réplica C 1 10 100 1000 10000 Taille Donnée 100000 1000000 10000000 7 NDS : Network Distance Service 8 Grid access control: Sygn • Permission = Authorization Certificate (AC) : Mechanisms for delegation of rights File group operations – – – Issuer Owner Capability (access control object + authorized action) – Validity – Signature 9 Encrypted Storage for Data Grids: Crypstore 10 10 Management of a Cooperative Cache in Grids Monitoring operations • data description • processed requests • transfers • replacements • used storage resource • Etc. organization cache data organization cache GRID cache Collective Coordinator cache Management operations • Set replacement method • Set default time to live • Set cache group • Set cache coordinator • Set collective work mode • Etc. data organization 11 Data Integration Correspondance négociée Médiateur négociateur Registre de services de données Médiateur négociateur Registre de services de données Zones de négociation imbriquées Base de correspondances Base de correspondances DS DS DS DS DS DS : Data Service (service de données) 12 Some Contributions to Pervasive/Ubiquitous Systems… and Other Distributed Systems (incl. Security and Privacy) 13 Pervasive, Ubiquitous, Mobile, Ambient, Ad Hoc ? • Introduction to pervasive systems • Hansel and Gretel are lost in the forest of PC definitions… • Basics (1) – Mobility (wireless) / autonomy – User (or device)-centric – Context-awareness (user prefs, environment) • Basics (2) – Lightweight appliances and devices – Proactivity Make the digital world/information omnipresent but invisible 14 PerSE •Context-Awareness •Proactivity •Service Composition context Models Adaptation 15 Architecture of a PerSE Base 16 PerSE Layers 17 Context Modeling and Context-Aware Pervasive Applications • • • Context = ? User/Application centric context Context-aware application platform 18 Access Control of Mobile Users • Chains of trust certificates: if A trusts B and B trusts C then A trusts C… to some level • Multi-layered adaptive certificates • Trust computing and reputation 19 Privacy-Preserving Reputation Systems • Reputation: aggregation of feedbacks • Query agent, target agent, source agents • Goal: computing the reputation while not revealing the individual feedbacks • Approach: use trust relations in the reputation protocol for enforce the privacy + “cut” feedbacks into pieces (“shares”) + use cryptographic tools 20 Authentication and Trust in Pervasive Systems 21 Mobile Requests • Information exchange between mobile peers (MANETs, VANETs) • Trajectory aware geocast request routing • Construction for each query of an ad hoc overlay of the peers that may participate to the delivery of the requested data 22 Data Replication in Small Worlds Server Original content 23 Replication in Ad Hoc Networks • Issues: instability, dynamicity, faults/disconnections • Basic idea: adapt the replication heuristics to the actual usage of the data, e.g.: – – – – Data highly accessed => replicate Rare data and planned disconnection => replicate Overloaded peer => replicate most accessed data Etc. • Pre-requisite: access logging + exchange of access data • Assumption: no central coordination – local decisions • Question : can local decisions lead to an acceptable (good ?) situation ? 24 Interface Adaptation and Context-Aware Browsing of a Patient Medical Record 25 Multimedia Content Adaptation + Adaptation of the interface wrt the end-user device Ongoing : Content Adaptation in MANETs 26 Semantic Protection of Multimedia Data • Multimedia => access control is not a binary decision • Access control <=> content adaptation • Coherence/Consistence of an adaptation • Legality of an adaptation => Access control = semantic adaptation decision 27 Semantic Clustering of Multimedia Queries: From Query Logging to Database Content and User Profile Discovery • Large number of data stores disseminated • Lack of indexes • Issues : – What are the pertinent/interesting data ? – What are the users interest ? – How to process a query ? • Logging of the users’ queries + clustering + communication of clustering info => identification of the community of users’ interests • Logging of a the queries issued by a specific user + matching to the community clustering => identification of the user’s profile • Usage: query optimization, data store management, recommendation, social computing, etc. 28 BAR-Tolerant Publish-subscribe P2P Systems Collaboration Modeling and Enhancing: a Game Theoretical Approach • Byzantine-Altruistic-Rational • Publish an information; disseminate the information to subscribers • Systems benchmarking tool • GT modeling of collaborative systems 29 Ambient Social Networks and Message Routing in DTN • Ambient social networks • Delay Tolerant Networks (DTN) and Opportunistic Networks • Mobility traces/model • Message routing 30 Ongoing work: User-centric Ubiquitous Multi-Scale Digital Ecosystems • • • • • • • • • • • • • Information retrieval in P2P systems Privacy-preserving personal data mining (EEXCESS project) Privacy-preserving recommendation systems (EEXCESS project) Privacy-preserving multimedia data routing Open data and user-as-sensor based ambient social services Game-theory-based cooperation modeling and enhancing in distributed systems Trust and reputation in B2B networks (AttestationLegale) Information protection in clouds Social-aware event driven architectures Mobile Crowd Sourcing, Sensing, and Computing: Intelligence, Aggregation, Resilience (if opportunity) Adaptive and information value-based protection of business processes (if opportunity) Security of the social web of things ??? 31 Faites de la recherche (au moins un peu) ! 32