SEMANTIC WEB INFORMATION SYSTEMS SWIS

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• SEMANTIC WEB INFORMATION SYSTEMS (SWIS)
• Data-intensive systems
• Data integration from heterogeneous sources
• Presentation personalization based on user
  preferences and browsing platform
• Use of Semantic Web technologies
• HERA METHODOLOGY
• Hera is a model-driven design methodology for
  SWIS. It distinguishes the following phases
• Data collection makes available data coming
  from different possibly heterogeneous sources.
• Presentation generation produces hypermedia
  presentations tailored to the user and the users
  browsing platform.
• Hera uses RDF(S), the foundation language of the
  Semantic Web, for model representations.
• PRESENTATION GENERATION PHASE
• The presentation generation phase of the Hera
  methodology is shown in Figure 1. It is based on
  the the following steps
• Conceptual design specifies the application
  data in a uniform manner independent from the
  input sources. The result of this activity is the
  conceptual model (CM).
• Application Design defines the navigational
  structure used for data delivery. The result of
  this activity is the application model (AM).
• Presentation Design specifies the look-and-feel
  aspects (e.g., layout, fonts) of the data
  presentation. The result of this activity is the
  presentation model (PM).
• Implementation based on the previous design
  specifications a pipeline of data transformations
  produces a Web presentation. The implementation
  comes in two flavors XSLT-based and Java-based.
  For the XSLT-based implementation, the XSLT
  stylesheets describe transformations between the
  RDF/XML serialization of the Hera RDF models.
• The design of the personalization of the
  presentation is distributed over all the
  previously identified design steps. The
  user/platform profile (UP) stores the user
  preferences and platform characteristics that
  influence the presentation before the user starts
  browsing. The UP is based on the CC/PP UAProf
  vocabulary that we extended with a user
  preferences component. Based on the UP attributes
  one can attach appearance conditions to the
  elements from CM, AM, and PM resulting in the
  so-called CM adaptation model, AM adaptation
  model and PM adaptation model.

TOOL Hera Presentation Generator (HPG) is an
integrated software environment that supports the
presentation generation phase of the Hera
methodology. It allows the graphical construction
of CM, AM, and PM, the definition and
instantiation of UP, and the building of a Web
presentation based on Hera data transformations.

• EXTERNAL TOOLS
• HPG uses
• Saxon for interpreting the data transformations
  specified as XSLT stylesheets.
• Jena for validating the Hera RDF models.
• Visio for implementing the CM, AM, and PM
  graphical builders.

Figure 2. Hera Presentation Generator interface.

• HPG has two main parts
• AM instance generation (left-hand side of Figure
  2). First CM is selected or built, and afterwards
  it is checked for validity. In the same way AM is
  selected or built, and after that it is checked
  for validity. After that one selects or
  constructs UP relevant for AM. Then, AM is
  unfolded (a technical step) and adapted. Based on
  the adapted AM, the specifications of the next
  transformation are generated. This transformation
  is used to populate the adapted AM with data
  given by the CM instance. The CM instance can be
  selected or created.
• Web presentation generation (right-hand side of
  Figure 2). First PM is selected or built, and
  then it is checked for validity. In the same way
  as for AM, PM is unfolded (a technical step) and
  adapted. After that one selects or constructs UP
  relevant for PM. Using the same technique as
  above, based on the adapted PM, the
  specifications of the next transformation are
  generated. This transformation is used to
  populate the adapted PM with data given by the AM
  instance. In the last transformation step the
  user selects the presentation format
  interpretable by the user browsing platform
  (HTML, HTMLTIME, SMIL, WML, or cHTML).
• Figure 3 shows an example presentation of the
  same data on different user platforms.

Figure 1. Presentation generation phase in Hera.
Figure 3. HPG-generated presentations for
different user platforms.