TU/e technische universiteit eindhoven Hera: Development of Semantic Web Information Systems Geert-Jan Houben Peter Barna Flavius Frasincar Richard Vdovjak

TU/e technische universiteit eindhoven Overview WIS design Hera methodology, RDF(S) Conceptual model and integration Application model and adaptation User interaction

TU/e technische universiteit eindhoven Motivation From Web pages to Web information system (WIS) Technologies from Semantic Web: RDF(S) Hera uses RDF(S) for effective support of WIS design

TU/e technische universiteit eindhoven WIS Design Generation of hypermedia presentations: navigation structure –Presentation objects, e.g. pages –Navigation connections, e.g. hyperlinks Integration from different sources: transparent repository –Management of semi-structured data Personalization: user adaptation

TU/e technische universiteit eindhoven Adaptation Presentations must be adaptable to different users/user platforms Devices (PC, PDA, WAP Phone, WebTV etc.) Device capabilities (display size, memory size, network speed, etc.) User preferences (desired layout, navigation patterns, etc.) User browsing history

TU/e technische universiteit eindhoven HERA Architecture

TU/e technische universiteit eindhoven Hera: WIS Design Methodology RMM, OOHDM, WebML, etc. Sequence of steps in designing a web application Model-driven approach: –data/navigation/presentation Data transformations: –towards HTML, WML, SMIL, etc. Use of RDF(S) to specify different models and XSLT to transform (meta)data –subclass/subproperty –extensibility, e.g. CC/PP vocabulary

TU/e technische universiteit eindhoven

TU/e technische universiteit eindhoven

TU/e technische universiteit eindhoven Conceptual Model (CM) Provides a uniform semantic view over different data sources that are integrated within a given Web application Consists of hierarchies of concepts relevant within the given domain, their properties, and relations Encoded in RDF(S)

TU/e technische universiteit eindhoven Conceptual Model Example

TU/e technische universiteit eindhoven Source Clusters Equipment Catalogue Photo Rental Photo Stock Agency Sources are Autonomous (Virtually) grouped to clusters based on the content they provide RDF(S), RQL capable

TU/e technische universiteit eindhoven Integration Model IM decouples the CM and Sources Articulations –actual links between the CM and the source ontologies –(a part of it) serves as a query on the source side Decorations –offer a way to rank sources within the same cluster –capture explicitly designer’s knowledge about sources –open possibilities for queries with constraints e.g. “I’m interested in the answer within 1s, otherwise forget it”

TU/e technische universiteit eindhoven Integration Model Ontology Application independent Path expression Articulation Decoration Processing instruction

TU/e technische universiteit eindhoven Application Model (AM) Captures navigational view over CM, describing hypermedia aspects Slices are meaningful presentation units: –Associated to concepts from CM –Containing properties/attributes and possibly other slices Slices are linked together with slice relationships: –Aggregation relationships: index, tour, indexed guided tour etc. –Reference relationships: link with an anchor specified Encoded in RDF(S)

TU/e technische universiteit eindhoven Application Model Example

TU/e technische universiteit eindhoven Adaptation WIS are accessed through multitude of devices and by different users –Device capabilities –User preferences –Browsing history Adaptation based on conditioning the appearance of slices in AM

TU/e technische universiteit eindhoven Adaptation/User Model Captures two kinds of adaptation Adaptability takes into account the context in which the user will use the presentation (e.g. the browsing platform) Adaptivity means that the presentation changes itself according to the “state of the user’s mind” while being browsed Consists of Device/User Profile captures “static” visual and platform preferences encoded in CC/PP User Model represents the dynamic user’s state, e.g. did the user visit (learn) this slice (concept) Application and Update Rules describe the behavior of the presentation (e.g. conditional slices in AM) and keep the user model up-to-date (AHAM rules)

TU/e technische universiteit eindhoven

TU/e technische universiteit eindhoven Profile Example Device/User Profile (CC/PP encoding) Screen size: 100x80 Preferred language: English English … No 100x80 …

TU/e technische universiteit eindhoven

TU/e technische universiteit eindhoven Adaptation Model Syntax Adaptability Condition Adaptivity Condition <rdfs:Class rdf:ID=“Slice.painter.main” slice:condition=“um:Biography = false”> <rdfs:Class rdf:ID=“Slice.painting.picture” slice:condition=“prf:ImageCapable=Yes”> <rdfs:Class rdf:ID=“Slice.painting.main” slice:condition=“um:Painter > 10”>

TU/e technische universiteit eindhoven User Interaction E-commerce applications often require WIS with broader functionality than just navigation through static web sites (known patterns: shopping carts, on-line payments, searches, etc.) The functionality includes also richer means of interaction with users via interaction elements: buttons, text entry forms, checkboxes, etc. Navigation objects (slices) with data content may depend on the interaction and/or system business logic, so it cannot be static

TU/e technische universiteit eindhoven User Interaction Specification Extension of AM specification: –Structural: interaction elements as “active” attributes capturing user actions (buttons, text fields, etc.) –Behavioural: operations assigned to interaction elements (dynamic navigation, data manipulation, adaptation, call of external Web Services, etc.) Consequence on WIS architecture: need for an engine providing the operations (as AHA! for adaptivity)

TU/e technische universiteit eindhoven Shopping Cart: example of CM data manipulations

TU/e technische universiteit eindhoven Conclusion & Future Work Explicit semantics in models, expressing concepts, their hierarchies and relationships Adaptation in all design steps including the CM and IM, and full support of adaptivity Experiment with higher ontology languages (e.g. OWL) as the basis for the different models Further development of authoring tools helping the designer to build models in all design steps –Query and transformation language, e.g. RAL

TU/e technische universiteit eindhoven