1 / 39

Web Information Systems Engineering

Web Information Systems Engineering. Flavius Frasincar flaviusf@win.tue.nl. Contents. What is a Web Information System (WIS)? WIS Features Problem: Data Management in WIS Solution: Model-Driven Methodology (with Tasks Separation) Methodologies for WIS: Strudel Methodology

alisa
Download Presentation

Web Information Systems Engineering

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Web Information Systems Engineering Flavius Frasincar flaviusf@win.tue.nl ISA

  2. Contents • What is a Web Information System (WIS)? • WIS Features • Problem: Data Management in WIS • Solution: Model-Driven Methodology (with Tasks Separation) • Methodologies for WIS: • Strudel Methodology • Hera Methodology • Summary ISA

  3. World Wide Web • 1990: Tim Berners Lee ( ) invents the World Wide Web • The Web success is based on: • hypermedia (link) nature: links allow for a natural and flexible access to information according to the associative nature of human mind • global availability • interoperability • simplicity • free etc. ISA

  4. Web Information Systems (WISs) • 1998: Tomas Isakowitz at al. coined the term Web Information Systems for: “information systems that are based on Web technology” • WISs are different from traditional information systems as they “have the potential of reaching a wider audience” through different platforms • There is an even increased need to integrate data as the data sources are distributed over the Web and they are possibly heterogeneous ISA

  5. Three Generations of WISs • First Generation: are based on hand-crafted HTML • Difficult to maintain (update) • Second generation: generate HTML on demand by automatically filling templates • Data is machine readable/transformable • Difficult to make the data machine understandable • Third generation: Semantic Web Information Systems (SWISs) are WISs based on Semantic Web technology (RDF, OWL etc.) • Data is machine understandable ISA

  6. Present the Deep Web • Deep Web vs. Surface Web: • 500 times larger • 1000 times better quality ISA

  7. WIS Features • Data-intensive: integrate data from multiple heterogeneous sources • Pervasive: support different platforms e.g. network (T1, 128K, 56K), display (PC, Palm, WAP Phone) • User Adaptable:consider user’s preferences and user’s state of mind while interacting with the system • Flexible: support semistructured data • Automatic: need little or no human intervention • User interactive: e.g. online shops (Amazon) ISA

  8. Problem: Data Management • WIS are hard to specify and implement • Methodologies exist for manual WIS design but few of them target automation • Difficult tasks to perform: • Multiplatform support • Automatic updates • Automatic site reconstruction (WIS Adaptation) • Optimize WIS performance (WIS Optimization) • Enforce WIS integrity constraints (WIS Analysis) • Achieve flexibility, extensibility etc. ISA

  9. Semistructured Data • It is characterized by: • Irregular structure: missing or additional attributes, multiple attributes • Few type constraints: attributes with different types in different objects, heterogeneous collections • Rapidly evolving schema or missing schema • It is typically modeled by a DLG (Directed Labeled Graph) • Examples: HTML, XML, RDF, LaTeX Bib etc . ISA

  10. Solution: Tasks Separation • Isolate and automatecommon tasks for WIS design: • Choose and access the data (data integration and retrieval) to be presented • Design the navigational structure for this data • Design the visual aspects of the presentation • Use a model-driven approach for task specification (the fairy says it brings “wisdom” [theory], “richness”[money], and “beauty” [judge it yourself] – Stefano Ceri) ISA

  11. WIS Presentation Generation Srategies • Static (eager approach): presentations are materialized completely, each page is precomputed • Dynamic or On-demand (lazy approach): after each link “click” the next page to be presented is computed ISA

  12. Methodologies • Dexter-based: HDM (Hypermedia Design Method) • ER-based: RMM (Relationship Management Methodology) • OMT-based: OOHDM • UML-based: OO-H (Conallen), UWE (UML-based Web Engineering),W2000 (HDM extension) • RDF-based: XWMF (eXtensible Web Modeling Framework), Hera • Other: Strudel, Araneus, WebML (Web Modeling Language), Autoweb, Trellis, XAHM (XML-based Adaptive Hypermedia Model), WSDM, W3DT etc. ISA

  13. Strudel Methodology http://www.research.att.com/~mff/strudel AT&T ISA

  14. Strudel Architecture ISA

  15. Input Data <publications> <pub id=pub1> <title>Declarative spec…</title> <author>Mary Fernandez</author> <author>Dan Suciu</author> <year>2000</year> <journal>VLDB</journal> <abstract>Strudel is a …</abstract> <category>Languages</category> <category>Methods</category> … </pub1> … <pub id=pub2> <title> Catching the …</ title> <author>Mary Fernandez</author> <author> Daniela Florescu </author> <year>1998 </year> <booktitle> SIGMOD </booktitle> <abstract> The Strudel …</abstract> <category>WIS</category> … </pub2> </publications> ISA

  16. Semistructured Data Model Direct Labeled Graph (DLG) ISA

  17. STRUQL(Site TRansformation Und Query Language) where Root”publications”r, r”pub” x, xl v {where l=“year” link YearPage(v) ”year” v, YearPage(v) ”paperPage” x, RootPage() ”yearPage” YearPage(v) collect RootPage{RootPage()}, YearPage{YearPage(v)} } … ISA

  18. Site Graph ISA

  19. STRUDEL Template Language • PaperPage collection: • <i> • <sif booktitle> • <sfmt booktitle> • <selse> • <sfmt journal> • </sif> • </i><br> • <sfor p in author> • <sfmt @p>, • </sfor><br> • <sfmt year><br> • RootPage collection: <html> <sfor p in yearPage order=ascend key=year> <sfmt @p link=@p.year> </sfor> </html> • YearPage collection: <h1><sfmt year></h1> <ul> <sfor p in paperPage> <li><sfmt @p></li> </sfor> </ul> ISA

  20. STRUDEL +/- + : Tasks separation (content and presentation) Declarative specifications (enables presentation content adaptation) Verification of integrity constraints (e.g. “All paper pages are reachable from RootPage”) • : Intermixes schema and content defintion in the data graph Does not separate navigation from visual details of the presentation Does not use standard technologies ISA

  21. Hera Methodology http://wwwis.win.tue.nl/~hera TU/e ISA

  22. HeraArchitecture ISA

  23. Hera Presentation Methodology Conceptual Design Conceptual Model Transformation Adaptation Design Application Design Application Model Transformation Presentation Design Presentation Model ISA

  24. 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 • Concept relationships are: • Attributerelationships: refer to literal values that characterize a concept • Referencerelationships: refer to other concepts ISA

  25. Example: CM ISA

  26. Example: CM in RDF/XML <rdfs:Class rdf:ID="Creator"/> <rdfs:Class rdf:ID="Painter"> <rdfs:subClassOf rdf:resource="#Creator"/> </rdfs:Class> <rdf:Property rdf:ID="creates" sys:cardinality="multiple" sys:inverse="created_by"> <rdfs:domain rdf:resource="#Creator"/> <rdfs:range rdf:resource="#Artifact"/> </rdf:Property> <rdfs:Class rdf:ID="Artifact"/> <rdfs:Class rdf:ID="Painting"> <rdfs:subClassOf rdf:resource="#Artifact"/> </rdfs:Class> <rdf:Property rdf:ID="year"> <rdfs:domain rdf:resource="#Artifact"/> <rdfs:range rdf:resource=“#Integer"/> </rdf:Property> <rdf:Property rdf:ID="picture"> <rdfs:domain rdf:resource="#Painting"/> <rdfs:range rdf:resource=“#Image"/> </rdf:Property> ISA

  27. Application Model (AM) • Captures the logical (navigational) aspects of the presentation • Based on the concept of slice which contains attributes and possibly other slices • A slice is a meaningful presentation unit • A slice is associated to a concept from CM • Slice relationships are: • Aggregation relationships: embed a set of slices (abstraction for index, tour, indexed guided tour etc). • Reference relationships: link abstraction with an anchor specified ISA

  28. Example: AM ISA

  29. Example: AM in RDF/XML <rdfs:Class rdf:ID="Slice.painting.main" slice:owner="CM #Painting"> <rdfs:subClassOf rdf:resource="#Slice"/> </rdfs:Class> <rdf:Property rdf:ID="slice-ref"> <slice:prop-ref rdf:resource="CM #ex_by"/> <rdfs:domain rdf:resource="#S.t.main"/> <rdfs:range rdf:resource="#S.p.picture"/> </rdf:Property> <rdf:Property rdf:ID=“link_1"> <rdfs:subPropertyOf rdf:resource =“#link”> <rdfs:domain rdf:resource="# S.p.picture"/> <rdfs:range rdf:resource="#S.p.main"/> </rdf:Property> <rdfs:Class rdf:ID="Slice.technique.main" slice:owner=“CM#Technique" slice:main="Yes"> <rdfs:subClassOf rdf:resource=“#Slice"/> </rdfs:Class> <rdfs:Class rdf:ID="S.painting.picture" slice:owner=“CM#Painting" slice:attr-ref=“CM#picture"> <rdfs:subClassOf rdf:resource="#Slice"/> </rdfs:Class> <rdf:Property rdf:ID="media"> <rdfs:domain rdf:resource="#S.p.picture"/> <rdfs:range rdf:resource=“#Image"/> </rdf:Property> ISA

  30. Adaptation • Captures two kinds of adaptation • Adaptability takes into account the device capabilities and user preferences (UAProf = User Agent Profile) • Adaptivity means that the presentation changes itself according to the “state of the user’s mind” while being browsed (UM = User Model) • Adaptation based on conditioning the appearance of slices using UAProf and/or UM • Adaptivity uses AHAM (Adaptive Hypermedia Application Model)update rules for updating UM ISA

  31. Adapted Application Model ISA

  32. Presentation Model • Defines the physical appearance of the presentation • 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 ISA

  33. Presentation Model ISA

  34. Presentation in Browsers WML SMIL HTML Wireless Markup Language Synchronized Multimedia Integration Language HyperText Markup Language ISA

  35. Implementation • Models are represented in RDF and they are serialized in RDF/XML • User Agent Profile (UAProf): a Composite Capability/Preference Profiles (CC/PP) vocabulary to model device capabilities and user preferences • XSLT processor for transforming between different model instances (stylesheet-based transformation) • Xalan (XSLT 1.0) • Saxon (XSLT 2.0): multiple output files support ISA

  36. Data Transformations • Step 0: Preparation • Substep 0.1: Application Model Unfolding creates the skeleton of an AM instance • Substep 0.2: Application Model Adaptation adds slice visibility conditions to the previous skeleton • Substep 0.3: Main TransformationSpecification Generation builds the specification for the next step • Step 1: Main Transformation populates the AM with the input CM instance • Step 2: Presentation Generation produces code for different browsers (HTML, WML, SMIL) ISA

  37. Data Transformations ISA

  38. Hera +/- + : Tasks separation (content, navigation, and presentation) Model-based specifications (enables presentation content adaptation) Uses standard technology: RDF, RDF/XML, XSLT • (Future Work): Specifications are semi-formal (difficult to check integrity constraints) Does not (yet) support user interaction ISA

  39. Summary • What is a Web Information System (WIS) • Features of WIS: data intensive, pervasive etc. • Design methodologies for WIS: • Strudel (from industry) • Hera (from university) • Model-based approach for WIS design • WIS design tasks separation: • Data Selection • Navigation • Presentation ISA

More Related