/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, XML-Based Automatic Web Presentation Generation Flavius Frasincar Geert-Jan Houben Databases & Hypermedia Group Division of Computer Science

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Contents 1.Motivation 2.Goals 3.Context: Hera Architecture 4.Design Methodology 5.Application Diagram 6.Presentation Diagram 7.Prototype: XML/XSL 8.Further Work 9.Conclusions

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Motivation There are a lot of methodologies for manual hypermedia presentation design but not for an automatic one. The need for presentation automation is justified by the fact that a lot of data is nowadays residing in the heterogeneous ‘deep web’ (searchable databases) as opposed to the ‘surface web’. There is an increasing need for presentation adaptation for different users/user platforms.

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Deep Web Deep Web vs. Surface Web: 500 times larger 1000 times better quality User/Platform Adaptation

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Goals Develop a methodology that supports automated hypermedia presentation design for Web-based Information Systems (WIS) that: –Integrates heterogeneous data sources. –Facilitates presentation (server/client-side) adaptation: Network (T1, 128K, 56K etc.) Display (PC, PDA, WAP Phone, WebTV etc.) User (preferences, interaction history etc.) –Enables semi-structured data queries.

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Context: Hera Architecture Relational Database Object-Oriented Database XML Database ODB-XML Wrapper RDB-XML Wrapper Mediator/ Integrator Logical Presentation Logical-WML Presentation HTML Presentation SMIL Presentation WML Presentation Logical-SMIL Presentation Logical-HTML Presentation Information Retrieval Hypermedia Presentation … … Query User/Platform Adaptation

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Design Methodology Based on RMM (Relationship Management Methodology). It distinguishes two levels: –Logical level: groups data into meaningful content units, called Slices. Artifact: Application Diagram –Presentation level: translates slices to presentation units, called Regions. Artifact: Presentation Diagram

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Methodology Phases Requirements Analysis E-R Design Application Design Presentation Design Implementation E-R Diagram Application Diagram Presentation Diagram Entity Relationship Slice Slice Relationship Region Region Relationship (Conceptual Model) (Application Model) (Presentation Model) Phase Artifacts:

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Application Diagram Based on the concept of slice which groups together attributes (having specific media types) and possibly other slices. Extends the E-R Diagram, each slice belongs to an entity. Slices are linked together with slice relationships: –Aggregation relationships: index, tour, indexed guided tour etc. –Reference relationships: link with an anchor specified.

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Application Diagram Example

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Presentation Diagram Based on the concept of region which contains attributes and possibly other regions. Each region has a rectangular area associated. Slices are translated to regions, one slice can be mapped to several regions. Slice relationships are materialized with: –Navigational relationships –Spatial relationships –Temporal relationships

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Region Relationships All region relationships can be guarded by a condition and/or an event. Navigational relationships: represent the classical hyperlinks. Possible events are: mouse-click, mouse-over etc. Temporal relationships: have associated a timeout event (e.g. time based on a media play duration). Spatial relationships: specify a relative position (qualitative or quantitative) between two regions.

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Presentation Diagram Example

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Synchronization Petri-net like notation for expressing synchronization (typical for multimedia data). Temporal Multidimensional

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Prototype: XML/XSL Implements the logical level of the design methodology. Based on transformation steps encoded in XSLT stylesheets that describe to an XSLT processor how to convert the input XML file to the desired output XML file. Tool: XSLT processor from Apache XML Project.

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Prototype Steps

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Retrieved Data Retrieved data is an instance of the conceptual model. DTDXML

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Step 1: Data Cleaning Enriches the retrieved data with information from the application domain model (appropriate relationship names, inverse of relationship instances). relationship.exemplifies XSL

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Application Model Describes at logical level the hypermedia aspects of the application. DTDXML <!ELEMENT slice (text | (slice-ref | hyperlink | index | guided-tour))> <slice id=“slice.painting.main” owner=“entity.painting”> relationship-ref=“relationship.painted_by”/> …

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Step 2: Logical Transformation Generation Builds the main transformation engine that packages the retrieved data into slices using the application model. This step is applied only once for one application (model), the output stylesheet is reused for each retrieved data instance. XSLT: automatic numbering (slice ID) and template modes (root/reference slice).

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Step 2 (cnt’d) XSL <xsl:stylesheet xmlns:xsl=“ xmlns:axsl=“ … …

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Step 3: Logical Transformation Packages the retrieved data into slices based on the stylesheet generated by the previous step. XSL

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, XSL Implements the presentation. There are two code generators built for: HTML (tables) and WML (cards). XSL HTML WML Step 4: Presentation Transformation

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Implementation HTML implementation (Netscape Navigator – Web Browser) WML implementation (Nokia 7110 – WAP Phone Emulator)

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Further Work Add media types to the model (now: strings and URLs). Build slices-on-demand on a servlet (now: precomputed). Set up user adaptation module based on a UM (User Model). Implement the presentation level of the proposed methodology. Make use of query technologies for XML and RDF: XQuery and RQL (now: SQL). Experiment with different kinds of applications (e.g. Electronic TV-Program Guide). Use Semantic Web: model descriptions in RDF(S). –Taxonomies of classes/properties based on inheritance.

/ department of mathematics and computer science TU/e eindhoven university of technology WebNet 2001October 26, Conclusions Methodology for automatic hypermedia presentation generation for the Deep Web (searchable databases): –Logical level (presentation semantics). –Presentation level (presentation implementation). Prototype based on XML/XSLT: –Platform adaptation (Web browser, WAP phone). Fosters UWA (Ubiquitous Web Applications): –web applications accessible anywhere at any time: PC, Laptop, PDA, WAP Phone, Watch Phone, WebTV etc.