-1- Philipp Heim , Thomas Ertl, Jürgen Ziegler Facet Graphs: Complex Semantic Querying Made Easy Philipp Heim 1 , Thomas Ertl 1 and Jürgen Ziegler 2 1 Visualization and Interactive Systems Group (VIS), University of Stuttgart, Germany 2 Interactive Systems and Interaction Design, University of Duisburg-Essen, Germany ESWC 2010 7 th Extended Semantic Web Conference Heraklion, Greece – June 1-3, 2010
ESWC 2010 7 th Extended Semantic Web Conference Heraklion , Greece – June 1-3, 2010. Facet Graphs: Complex Semantic Querying Made Easy. Philipp Heim 1 , Thomas Ertl 1 and Jürgen Ziegler 2 1 Visualization and Interactive Systems Group (VIS), University of Stuttgart, Germany - PowerPoint PPT Presentation
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-1- Philipp Heim, Thomas Ertl, Jürgen Ziegler
Facet Graphs: Complex Semantic Querying Made Easy
Philipp Heim1, Thomas Ertl1 and Jürgen Ziegler2
1 Visualization and Interactive Systems Group (VIS), University of Stuttgart, Germany2 Interactive Systems and Interaction Design, University of Duisburg-Essen, Germany
ESWC 20107th Extended Semantic Web ConferenceHeraklion, Greece – June 1-3, 2010
-2- Philipp Heim, Thomas Ertl, Jürgen Ziegler
Outline
1. How to access information in the Semantic Web?
2. Faceted Search: An Introduction
3. Faceted Search in the Semantic Web
4. Facet Graphs
5. Evaluation
6. Discussion
7. Conclusion and Future Work
-3- Philipp Heim, Thomas Ertl, Jürgen Ziegler
Outline
1. How to access information in the Semantic Web?
2. Faceted Search: An Introduction
3. Faceted Search in the Semantic Web
4. Facet Graphs
5. Evaluation
6. Discussion
7. Conclusion and Future Work
-4- Philipp Heim, Thomas Ertl, Jürgen Ziegler
1. How to access information in the Semantic Web? Common Web:
Entering words in an input field (e.g. Google or Bing) Problem ambiguity:
Natural language is ambiguous!Finding the right information, however, requires the semantic of what should be searched to be specified by the user.
Solution:Artificial query languages like SPARQL that are uniquely defined. Access via SPARQL endpoints (e.g. DBpedia or the LOD cloud).
SELECT DISTINCT ?object ?label WHERE {
?object rdf:type <URI of Football player> . ?object rdfs:label ?label .
}
-5- Philipp Heim, Thomas Ertl, Jürgen Ziegler
1. How to access information in the Semantic Web? Problem required knowledge:
SPARQL requires the language to be learned by the user (rather a task for experts).
Solution:Intuitive graphical interfaces to express search queries that are semantically unique but do not require any extra knowledge.
-6- Philipp Heim, Thomas Ertl, Jürgen Ziegler
Outline
1. How to access information in the Semantic Web?
2. Faceted Search: An Introduction
3. Faceted Search in the Semantic Web
4. Facet Graphs
5. Evaluation
6. Discussion
7. Conclusion and Future Work
-7- Philipp Heim, Thomas Ertl, Jürgen Ziegler
2. Faceted Search: An Introduction
Example:
facets
facet(1) select
attribute
result set
(2) filter
(3) update
faceted search:
-8- Philipp Heim, Thomas Ertl, Jürgen Ziegler
2. Faceted Search: An Introduction
(1) select
Audiobooks
result set
(3) update
(2) filter(1) select
Audiobooks
number of results
facetcategory
facet count
facet attribute
-9- Philipp Heim, Thomas Ertl, Jürgen Ziegler
2. Faceted Search: An Introduction
Advantages:- Facets and their attributes are given (reduced effort)
- Attributes are categoriezed (understanding)
- No facet attribute can lead to an empty result set
- Resulting number of resultsis shown in advance
- Rapid update of result set (dynamic queries)
- Selected attributes are shown and can be deselected
-10- Philipp Heim, Thomas Ertl, Jürgen Ziegler
Outline
1. How to access information in the Semantic Web?
2. Faceted Search: An Introduction
3. Faceted Search in the Semantic Web
4. Facet Graphs
5. Evaluation
6. Discussion
7. Conclusion and Future Work
-11- Philipp Heim, Thomas Ertl, Jürgen Ziegler
3. Faceted Search in the Semantic Web
mspace (Hearst et al. 2002: Finding the Flow in Web Site Search):
Disadvantages: 1.No facet count(number of results to expect)2.First order facets only (directly connected to the result set)
-12- Philipp Heim, Thomas Ertl, Jürgen Ziegler
3. Faceted Search in the Semantic Web
Parallax (Huynh and Karger 2009: Parallax and companion: Set-based
browsing for the Data Web):
Advantage:1.Hierarchical facets possible(second or higher order facets)
Disadvantages: 1.Hierarchy not visible2.Browsing required
-13- Philipp Heim, Thomas Ertl, Jürgen Ziegler
3. Faceted Search in the Semantic Web
Tabulator (Berners-Lee et al. 2008: Tabulator Redux: Browsing and
writing Linked Data) :
Advantages:1.Hierarchical facets2.Hierarchy on one page
Disadvantages: 1.Attributes get partitioned in different subtrees2.Redundant attributes
-14- Philipp Heim, Thomas Ertl, Jürgen Ziegler
Outline
1. How to access information in the Semantic Web?
2. Faceted Search: An Introduction
3. Faceted Search in the Semantic Web
4. Facet Graphs
5. Evaluation
6. Discussion
7. Conclusion and Future Work
-15- Philipp Heim, Thomas Ertl, Jürgen Ziegler
4. Facet Graphs Idea: Facets and result set are represented as nodes in a
graph visualization
Theme SubjectYearDecade Story Title
result set
facets
categories(labeled edges)
-16- Philipp Heim, Thomas Ertl, Jürgen Ziegler
4. Facet Graphs
How to extract facets from RDF data?
club2
club1club
type
type
result set
class objects
venue2
venue1
venue
type
type
ground
ground
venue3 type
facet
properties
objects
class
facetresult set
1. Defining the result set class(e.g. German football club)