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CS 586 – Distributed Multimedia Information Management. Prof. Dennis McLeod. About the paper. Towards Ontology-Driven Discourse: From Semantic Graphs to Multimedia Presentations In Proceedings of the 2nd International Semantic Web Conference, 2003
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CS 586 – Distributed Multimedia Information Management Prof. Dennis McLeod
About the paper . . . Towards Ontology-Driven Discourse: From Semantic Graphs to Multimedia Presentations In Proceedings of the 2nd International Semantic Web Conference, 2003 By: Joost Geurts, Stefano Bocconi, Jacco van Ossenbruggen, and Lynda Hardman Presented by: Gabriela Gutierrez, February 11, 2004
Overview • Introduction • Example Scenario: Rembrandt • Process 1: From Semantic Graph to Structured Progression • Process 2: From Structured Progression to Multimedia Presentation • Conclusion
Introduction • Traditionally • Applying Semantic Web technology to multimedia information systems focuses on using annotations and ontologies to improve retrieval process • Presentation of data is “detail” best left to CSS or XSLT style sheets • In this paper • Claim that importance and complexity of effective presentation design is grossly underestimated • Concentration on improving the presentation of the retrieval results
Introduction • Human professional designers must understand: • Underlying semantics of the client’s information • Most effective order, grouping and priorities for structuring this information • Most effective means of using the chosen medium to convey the information
Introduction • Information presentation design is a knowledge-driven process. It requires: • Sufficient knowledge about domain • Knowledge on ordering, grouping and prioritizing information • Knowledge about media design • Selection of most appropriate medium • Understanding of medium characteristics in order to choose an effective means to achieve the communication goal
Introduction • Problem: • Professional designers can only design data-driven web sites if the underlying data, its semantics and target audience are relatively homogeneous. • Variety of data sources, semantic relations, output devices, and user profiles forces content providers to adopt one-size-fits-all approach. • Automation is needed in order to make the presentation of information knowledge-driven.
Introduction • Assumptions: • Multimedia items are properly annotated • Annotations represent domain relations in a semantic graph (e.g. RDF) • Graph has associated Domain ontology • There is a Discourse ontology containing information about different document genres and building blocks for creating documents for each genre • There is a Design ontology containing media design knowledge
Example Scenario: Rembrandt • Web query: “life and work of Rembrandt” • User-selected type of structured progression: disc:Biography • User-selected output medium: non-interactive multimedia presentation • Semantic graph = retrieval component’s results + domain ontology semantics relations • Structured progression = typical facts (name, DOB,…) + career facts + personal life info
Process 1: From Semantic Graph to Structured Progression • CSS and XSLT operate purely on the XML level of RDF’s serialization syntax w/o any understanding or support for semantics of RDF data model • Transformation process needs access to knowledge on RDF Schema level • For querying underlying domain ontology • For access to its own operating knowledge
Process 1: From Semantic Graph to Structured Progression • Several transformations prototyped in Java and Prolog environments • Direct access to a Sesame RDF Schema-based repository • Can use any query language supported by Sesame (RQL, RDQL, SeRQL) to gain direct access on the RDF instance level and the RDF Schema Level • Transformation process uses (declarative) domain and discourse-specific knowledge, while (procedural) transformation code remains generic
Process 1: From Semantic Graph to Structured Progression • Transformation code uses RQL query to retrieve classes that Rembrandt instance belongs to . . . dom:Artist • Discourse ontology defines instance of disc:ArtistBiography that has disc:Subject property with value dom:Artist • Structured progressions have a disc:narrativeUnits property that specifies the disc:NarrativeUnits that can be used to construct it (e.g. disc:PersonalData, disc:PrivateLife and disc:Career)
Process 1: From Semantic Graph to Structured Progression • Narrative Units have associated rules used to select matching content • Example: disc:PrivateLife • Rules to select information about family relations from semantic graph • Graph includes relation dom:isMarried between Rembrandt and Saskia_Uylenburgh • Rule #3 in following table can use domain relation to select Saskia in the disc:Role of disc:Spouse • Rules can be applied recursively • Rule #3 specifies that PrivateLife is the narrative unit that can be used for a subsequent nested story line • Process continues until no more rules can be applied or a rule specifies that no further expansion should happen
Process 1: From Semantic Graph to Structured Progression • After all rules have been applied: • Biography w/ 3 narrative units • disc:PersonalData (Rembrandt in role of disc:MainCharacter) • disc:Career (Chiaroscuro in role of disc:Technique) • Disc:PrivateLife (Saskia_Uylenburgh in role of disc:Spouse)
Process 2: From Structured Progression to Multimedia Presentation • Two-step process: • Structured progression transformed into Document Structure • Decisions on output medium (e.g. text, interactive hypermedia, passive multimedia) • Document Structure transformed into a tree of formatting objects • Detailed layout and formatting decisions (e.g. timing of presentation, transition effects)
Process 2: From Structured Progression to Multimedia Presentation • Advantage: • Mapping discourse-specific narrative units to more general document elements allows for more commonly applicable formatting rules (e.g. disc:PrivateLife can be mapped to document section element, relying on common formatting rules for section-level elements) • Disadvantage: • There is always a level that can no longer be specified in terms of document structure (e.g. a figure w/ too much detail) • Solution: detailed structures copied directly into document structure in step 1 in order to define specific rules in step 2 to deal w/ formatting directly
Conveying Document Structure • Transforming a document structure into presentation constructs uses Cuypers library • Uses constraint solving techniques to verify that a presentation construct conforms to delivery-context constraints (e.g. screen size) • Allows alternative formatting specification if constraints are violated • A rule that transforms a document structure into presentation construct has 2 discourse parameters: • disc:NarrativeType • disc:Role • Parameters allow system to adapt formatting of presentation to convey message more effectively
Conveying Discourse Semantics Directly • Depending on their function, we need to define formatting for different media types • Rembrandt self-portrait (disc:Portrait in disc:PersonalData vs. disc:Painting illustrating Chiarocuro) • Awareness of impact of different media modalities • Fall-back rules • Image not identified as either disc:Portrait or disc:Painting should be applied generic formatting for images since mm:Painting and mm:Portrait are subclasses of mm:Image
Conclusion • Only short presentations have been generated to date, based on restricted domain ontology • Focus has been on single discourse structure (biography) and single document structure (multimedia presentation) • Additional research required to scale the system to more realistic scenarios • Under investigation: how knowledge about the user interacts w/ discourse and design knowledge used in current prototype