Enabling interoperable and rights-aware DRM using the Semantic Web

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This presentation, which was carried out at the DRM track of SmartUniversity'07, presents a Semantic Web approach to Digital Rights Management. This approach is based on a Copyright Ontology, …

This presentation, which was carried out at the DRM track of SmartUniversity'07, presents a Semantic Web approach to Digital Rights Management. This approach is based on a Copyright Ontology, implemented using OWL and DL reasoning.

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  • 1. Enabling interoperable and rights-aware DRM using the Semantic Web Roberto García [email_address] Universitat de Lleida, Spain September 20, 2007 Sophia Antipolis, France
  • 2. Where did you say you come from? Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 3. Table of Contents
    • Introduction
      • Semantic Web
    • Objectives
    • Specification
    • Conceptualisation
    • Implementation
    • Evaluation
    • Conclusions
    • Future Work
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 4. Introduction
    • Digital media: easy production and copy
    • Digital Rights Management (DRM)
    • Windows Media DRM, iTunes FairPlay, RealNetworks Helix, Sony MagicGate…
    DRM copy play … Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 5. Introduction
    • Internet: easy distribution
    • DRM interoperability
    REL Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 DRM DRM DRM
  • 6. Introduction
    • Need for a standard REL (Rights Expression Language)
    • Some efforts:
      • XML-based RELs
        • Formal syntax XML Schema for standard grammar
        • Informal semantics Rights Data Dictionaries
      • Creative Commons simple predefined licenses
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 7.
    • XML-based RELs:
      • Limited expressivity
      • No interoperability mechanisms
      • Informal semantics, re-implement for each tool
    • Creative Commons:
      • Predefined and closed set of licenses
      • Non-commercial purposes
    Introduction Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 8. Introduction
    • DRM Watch: “2005 Year in Review: DRM Standards” 1
      • “… consumer complaints have moved beyond overly restrictive DRMs to lack of interoperability among them…”
      • “… we see no production implementations …”
      • “… ContentGuards asserts its patents apply to any REL implementation in DRM…”
    • Electronic Frontier Foundation 2
      • “… fail to accommodate… copyright regimes.”
    1 http://www.drmwatch.com 2 http://www.eff.org Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 9. Introduction
    • DRM standardisation difficulties
      • Internet/Web open and heterogeneous
      • Copyright complex domain
      • High level of abstraction (not bits or pixels)
    • Concentrate on the roots, formalise SEMANTICS
    ODRL “ Duplicate ” Reproduction Right Copy MPEG-21 “ Adapt ” CC “ Reproduction ” Copyright Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 10. Introduction
    • Why semantics are needed?
    • Common scenario : web search and language ambiguity
      • Computers get confused because… …though we “see”:
      • " Smart University " (3rd edition) is an educational program dedicated to advanced technologies of Smart Card, e-ID, . ..
      • SMART (Sisterhood Mobilized for AIDS/HIV Research and Treatment) was founded in 1998...
      • SMART University welcomes all women infected or affected by HIV/AIDS who...
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 11. Introduction
    • Computers “see”:
      •  Smart University   
      • 
      • SMART University 
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 12. Introduction
    • XML allows some degree of automation
      • Data Interface: set of specific tags and grammar ( DTD , XMLSchem a)
        • < music >
        • < album format=“ mp3 ”>
        • < author type=“ group ”>Faithless</ author >
        • < title >Insomnia</ title >
        • ...
        • </ album >
        • </ music >
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 13. Introduction
    • With XML computers “see”:
        • < music >
        • < album format=“ mp3 ”>
        • < author type=“ group ”>  </ author >
        • < title >  </ title >
        • ...
        • </ album >
        • </ music >
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 14. Introduction
    • Interoperability problem
    • Global agreement required
      • Just formal syntax, no semantic interoperability tools
      • < music >
      • < album format=“ mp3 ”>
      • < author tipo=“ group ”> ...</ author >
      • < title >...</ title >
      • ...
      • </ album >
      • </ music >
    < song > < group >...</ group > < title >...</ title > < album >...</ album > <file>...</file> ... </ song > ? Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 15. Introduction
    • If the previous tool is presented a piece of data based on a new schema:
      • < song >
      • < group >Garbage</ group >
      • < title >Version 2.0</ title >
      • < album >Version 2.0</ album >
      • <file>...</file>
      • ...
      • </ song >
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 16. Introduction
    • That tool “sees”:
        • <  >
        • <  >  </  >
        • <  >    </  >
        • <  >    </  >
        • <  >...</  >
        • ...
        • </  >
    • Code interoperability rules case by case
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 17. Introduction
    • Semantic Web proposal
      • Web + Knowledge Representation
      • Web wide formal semantics
    • RDF : semantic net, graph model
    • RDF Schema : classes, inheritance,…
    • Web Ontology Language (OWL)
      • OWL-DL : scalable (decidable and tractable)
    • Semantic Web Rules
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 18. Introduction
    • RDF provides graph model:
    • Graph can model:
      • trees (XML)
      • tables (DBs)
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 19. Introduction
    • RDFSchema : OOP-like primitives
      • type
      • class, property
      • subclass, subproperty
      • domain, range
    Song Class Audio Class subClassOf http:// music .org / song1 type title Property attribute Property subPropertyOf Literal Class “ ...” title type domain range RDFSchema RDF type Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 20. Introduction
    • Web Ontology Language (OWL)
      • Logic reasoning
      • Primitives for semantic interoperability
        • Equivalent classes and properties equivalentClass , equivalentProperty
        • Disjoint classes disjointWith
        • Inverse, transitive, symmetric properties inverseOf , TransitiveProperty , SymmetricProperty
        • Cardinality maxCardinality , minCardinality
        • Unique value properties FunctionalProperty
        • Identificative properties InverseFunctionalProperty
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web
  • 21. Table of Contents
    • Introduction
    • Objectives
    • Specification
    • Conceptualisation
    • Implementation
    • Evaluation
    • Conclusions
    • Future Work
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 22. Objectives
    • Semantic Web approach to DRM:
      • Knowledge Representation tools
      • Web Wide applicability
    • Benefits:
      • Formalise semantics
      • Facilitate interoperability and implementation
      • Overcome REL patent ?
      • Include copyright
      • Support full value chain
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 23. Objectives
    • Ontology development based on Methontology :
      • Specification
      • Conceptualisation (and formalisation)
      • Implementation
      • Evaluation
    • XML Semantics Reuse
      • Profit from existing XML Schema based RELs
      • Formalise implicit semantics
      • XML Schema to Web Ontology
      • XML data to semantic data (RDF)
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 24. Table of Contents
    • Introduction
    • Objectives
    • Specification
    • Conceptualisation
    • Implementation
    • Evaluation
    • Conclusions
    • Future Work
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 25. Specification
    • Copyright domain analysis
    • Generic Ontology
      • WIPO 1 worldwide harmonisation
    • Literary, artistic and scientific works (not ideas)
    • Maybe derived, but always original
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 1 World Intellectual Property Organisation Copyright Treaty, 1996
  • 26. Specification Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 27. Specification
    • Applicable to the
      • “ Controlled P2P metadata diffusion scenario”
    Peer A Peer B <rdf:RDF> <rdf:RDF> <rdf:RDF> <rdf:RDF> Make Available Right <rdf:RDF> Reproduction Right Scenario Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 28. Table of Contents
    • Introduction
    • Objectives
    • Specification
    • Conceptualisation
      • Creation, Rights and Action Model
    • Implementation
    • Evaluation
    • Conclusions
    • Future Work
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 29. Conceptualisation
    • Complex domain, build model in three steps:
      • Creation Model
      • Rights Model
      • Action Model
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 30. Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Victor Hugo’s Les Misérables Creation Model
  • 31. Conceptualisation
    • Work
      • “ Mozart's The Magic Flute”. ISWC
    • Manifestation
      • “ The printed scores”. ISBN
    • Performance
      • “ A scenic play”.
    • Fixation
      • “ A sound recording”. ISRC
    • Communication
      • “ An Internet stream”.
    • Instance
      • “ A CD”. UPC
    •  has Derivation ┙
    •  has Manifestation ┙
    •  has Performance ┙
    •  ha sFixation ┙
    •  ha sCommunication ┙
    •  ha sInstance ┙
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Creation Model
  • 32. Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Rights Model
  • 33.
    • End-users do not hold rights
      • Usage licenses
      • Special permissions:
        • Quotation
        • Education
        • Information
        • Official Act
        • Private Copy
        • Parody
        • Temporary Reproduction
    Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Rights Model
  • 34.
    • Actions, the building blocks
    Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 35.
    • Actions governed by Economic Rights:
      • Reproduction Right : copy
      • Distribution Right : distribute; sell, rent, lend
      • Public Performance Right : perform
      • Fixation Right : record
      • Communication Right : communicate; retransmit, broadcast, make available
      • Transformation Right : transform; adapt, translate
    Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 36. Conceptualisation
    • End-user actions, to use a…
      • manifestation: buy
      • instance: buy
      • performance: attend
      • communication: access
        • broadcast: tune
        • something made available: access
    • picture, sculpture
    • book, CD, DVD
    • projection, recital, exhibition
    • TV channel, radio station
    • web page, stream
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 37.
    • Altogether: model copyright value chains
      • E.g. “serials adapted from literary works”
    Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 38.
    • Actions for users’ special permissions:
      • Quotation Right : quote , limited extent copy , usually requiring an attribute action
      • Private Copy Right : copy producing a reproduction for private consumption
      • Education Right : educational act , any copy , communicate or perform with educational or research purposes
      • Temporary Reproduction Right : a copy that produces a temporal reproduction
    Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 39.
    • Case roles (linguistics): relate actions to involved entities
    Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 40.
    • License building primitives:
      • Event Patterns : to state what is obliged, permitted or prohibited
        • Built from actions and case roles
    Conceptualisation Scenario All copy events performed by agent “ granted ” who copies “ content01 ” from “ PeerA ” to two peers from the set “ PeerB, PeerC, PeerD ” at any time point six months after “ 2007-06-01 ” Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 41.
    • License building primitives:
      • Agree : model permissions
        • theme points to the permitted event pattern
    Conceptualisation Scenario Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 42.
    • License building primitives:
      • consequence : model obligations
        • Points to the obliged event pattern
    Conceptualisation Scenario Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 43.
    • License building primitives:
      • condition : model a priori conditions
        • Points to the condition event pattern
      • Disagree : model prohibitions
        • theme points to the prohibited event pattern
      • Other concepts:
        • Transfer: model interchanges, commercial or not.
        • Time
        • Location
        • ...
    Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 44.
    • Rules, examples:
      • First sale exhaustion: ∀ s:Sell, ∀ i:Instance theme(s,i) -> ¬ ∃ s’:Sell theme(s’,i) ∧ s≠s’
      • Assign author rights on Manifest:
    Conceptualisation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model
  • 45. Table of Contents
    • Introduction
    • Objectives
    • Specification
    • Conceptualisation
    • Implementation
    • Evaluation
    • Conclusions
    • Future Work
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 46. Implementation
    • One conceptual model, many implementations
    • Semantic Web implementation with OWL
    • OWL-DL variant
      • enables tractable and decidable reasoning for use-license checking, scalability
    • Additionally, Semantic Web rules
    OWL Full OWL DL OWL Lite + expressivity - complexity Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 47. Implementation
    • Rights and License Patterns implemented as Classes
      • Copyright, Reproduction Right, Copy, CopyPattern,...
    • Uses implemented as Instances
      • u
    • if u ∈ Copy Pattern then license pattern authorises u
    Reproduction Right Copy Copyright Copy Pattern u ? Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 48. Implementation
    • License Pattern Class built from constraints on kind of actions, agents, time points, locations, etc.
    • OWL Building Blocks
      • Classes for actions (e.g. Copy)
      • Logical operators (AND, OR, NOT)
      • OWL Restrictions , constraints on case roles (e.g. agent all values from PublisherSubscribers)
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 49. Implementation
    • Copy pattern restricted to:
      • digital object ( theme )
      • group of users ( agent )
    • or
      • non-commercial ( aim )
    • depending on
      • time range ( pointInTime )
    Scenario Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 50. Implementation
    • Description Logic notation for the commercial copy pattern:
      • Pattern ≡ Copy ⊓ ∀ pointInTime .≥ 2007-01-01,≤ 2007-06-30 ⊓ ∀ agen t.PublisherSubscribers ⊓ (≥ 1 agent ) ⊓ ∃ theme .{urn:doi.10.1032/…} ⊓ (≤ 1 theme )
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 51. Implementation
    • Patterns permitted by Agree actions and prohibited by Disagree ones.
    • Algorithm:
      • If disagreed  not allowed
      • If agreed and not disagreed  allowed
      • If not agreed  not allowed
    • Disagree precedence allows:
      • Revocation
      • More complex patterns
      • Avoid DL reasoners limitations (details Annex A)
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 52. Implementation Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Copy all copy actions Pattern 2 Pattern 2’ Allowed Pattern 1 Agree Disagree Agree
  • 53. Implementation
    • OWL-DL reasoners services:
      • Satisfiability : consistency, license verification
      • Subsumption : compute subclasses
        • License interactions
        • License search
      • Instance Checking : class an individual belongs to
        • Check uses against licenses
      • Other:
        • Debugging , justifications for conclusions
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Pattern A Pattern B Pattern Use
  • 54. Implementation
    • OWL-DL limitations:
      • No explicit variables
      • Difficult to model rules (if … then …)
    • Semantic Web rules
      • Variables
      • Classical rules
      • Built-ins (math, comparisons, date/time ops,...)
      • Integrates OWL
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 55. Table of Contents
    • Introduction
    • Objectives
    • Specification
    • Conceptualisation
    • Implementation
    • Evaluation
    • Conclusions
    • Future Work
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 56. Evaluation
    • Map MPEG-21 and ODRL ontologies to Copyright Ontology
      • Based on XML Semantics Reuse Methodology
        • XML Schemas  OWL Ontologies
        • XML instances  RDF metadata
    • MPEG-21, ISO/IEC 21000
      • Part 5 – REL, XML Schemas:
        • Core  RELOnto-R
        • Standard Extensions  RELOnto-SX
        • Multimedia Extensions  RELOnto-MX
      • Part 6 – RDD, informal ontology  RDDOnto
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 57. Evaluation
    • ODRL 1.1 (OMA V1.0 DRM REL)
      • XML Schemas:
        • Expression Language  ODRLOnto-EX
        • Data Dictionary  ODRLOnto-DD
    • Benefits
      • Check Copyright Ontology coverage
      • Apply semantic tools existing RELs
        • Validate MPEG-21 RDD standard
        • Implement Data Dictionary inheritance
        • License checking
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 58. Evaluation
    • Build SemDRMS Semantic Digital Rights Management System
      • Controlled P2P metadata diffusion
    Peer A SemDRM copy make available Licenses Store DL Reasoner Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 59. Evaluation
    • Digital Media Project (DMP)
      • Traditional Rights and Usages informal descriptions, difficult to incorporate into DRM systems
        • Quote
        • Private Copy
        • Time Shift
        • ...
    • Copyright Ontology: profit from copyright model and capture rights exceptions
      • No enforcing mechanisms, accountability
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 60. Evaluation
    • Quote scenario
      • Right exception model:
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 61. Evaluation
    • Concrete quote action:
      • Tim wants to quote 10 seconds of a work by John
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 62. Evaluation
    • Checking:
    • Result:
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 63. Evaluation
    • Private Copy scenario
      • Right exception model:
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 64. Evaluation
    • Concrete private copy action:
      • Peter wants to produce a personal copy of “My best quote of the year”
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 65. Evaluation
    • Checking:
    • Result
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 66. Table of Contents
    • Introduction
    • Objectives
    • Specification
    • Conceptualisation
    • Implementation
    • Evaluation
    • Conclusions
    • Future Work
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 67. Conclusions
    • Concentrate on semantics
    • Ontology , more expressivity
    • Include copyright
    • Facilitate implementation and interoperability
      • Reuse DL reasoners for license checking
      • RELs ontologies, XML Semantics Reuse
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 68. Table of Contents
    • Introduction
    • Objectives
    • Specification
    • Conceptualisation
    • Implementation
    • Evaluation
    • Conclusions
    • Future Work
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 69. Future Work
    • Full SemDRMS based on OWL-DL Copyright Ontology
    • Complete Mappings to Copyright Ontology
      • MPEG-21 REL Ontologies
      • ODRL Ontologies
      • Creative Commons
    • Security and trust through RDF signatures
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 70. More details: http://rhizomik.net/ontologies/copyrightonto http://rhizomik.net/semdrms http://rhizomik.net/~roberto/thesis Smart University DRM, from research to implementations Thank you for your attention Roberto García [email_address] Universitat de Lleida, Spain
  • 71. Smart University DRM, from research to implementations Annex A Implementation Details How to deal with licenses using Description Logic reasoners
  • 72. Implementation
    • Pattern ⊑ Copy
    • Pattern ≡ ∀ pointInTime.≥ 2006-01-01, ≤ 2006-06-30 ⊓ ∃ agent.{granted} ⊓ ∃ origin.{peerA} ⊓ ∃ theme.{fragment01} ⊓ (≤ 2 recipient) ⊓ ∀ recipient.{peerB, peerC, peerD}
    Scenario Agree Problem Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 73. Implementation
    • Problem : Open World Assumption (OWA)
    • OWA sensible constructs:
      • m ax Cardinality (≤ n): new facts can make cardinality ≥ n
      • allValuesFrom ( ∀ R.C): new facts where R.(¬C)
    • OWA insensible constructs:
      • m in Cardinality (≥ n): once ≥ n, new facts cannot make cardinality ≤ n
      • someValuesFrom ( ∃ R.C): once R.C, new facts cannot make ¬( ∃ R.C)
    0 1 3 2 maxCardinality 2 (n ≤ 2) minCardinality 3 (n ≥ 3) New facts “ OPEN WORLD” Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 74. Implementation
    • Metalevel negation to overcome OWA
    • Agree OWA insensible constructs
      • ∃ , ≥,…
    • Disagree “negated” OWL sensible constructs
      • ∀ R.C  ∃ R.¬C
      • ≤ n  ≥ n+1
    • Allowed(u)  Agree.theme(u) ⊓ ¬Disagree.theme(u)
    Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 75. Implementation
    • Pattern’ ⊑ Copy
    • Pattern’ ≡ ∀ pointInTime.≥ 2006-01-01, ≤ 2006-06-30 ⊓ ∃ agent.{granted} ⊓ ∃ origin.{peerA} ⊓ ∃ theme.{fragment0001}
    • Pattern’’ ≡ Pattern’ ⊓ ( ( ≥ 3 recipient) ⊔ ∃ recipient.( ¬ {peerC, peerD, peerB}) )
    Scenario Agree Disagree Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007
  • 76. Implementation Scenario [ a Copy; agent :granted; origin :peerA; theme :fragment02 ; recipient :peerB ] [ a Copy; agent :granted; origin :peerA; theme :fragment01; recipient :peerC, :peerD ] [ a Copy; agent :granted; origin :peerA; theme :fragment01; recipient :peerB , :peerC, :peer E ] Allowed Copy Pattern ’ Pattern’’ Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007