In this contribution, we address exploratory search where a user is faced with an information need concerning a domain he lacks specific knowledge. Based on the work of Delbru et al., which introduced metrics to measure the navigational quality of automatically selected facets for RDF data, we apply those findings to the semantically richer TMDM and show how exploratory search functionality can be combined with existing approaches.

1. Facet-based
Exploratory
Search in
Topic Maps
M. Ueberall,
O. Drobnik
Introduction
Metrics
Facet-based Exploratory Search
Prototype in Topic Maps
Comparison
Summary
M. Ueberall, O. Drobnik
Telematics Group, Institute of Computer Science
Goethe-University, Frankfurt/Main, Germany
2008 / 10 / 16

2. Facet-based
Exploratory
Search in
Topic Maps
Motivation and Objective
M. Ueberall,
O. Drobnik
Introduction
Metrics
• The majority of Topic Maps based applications uses
Prototype
Comparison
faceted classification
Summary • Still, generic exploratory search interfaces for Topic
Maps which shield the user from representational
details have hardly been discussed
• In the following, we
• extend an RDF based approach [Delbru et al. 2006]
• discuss combinations with existing user interfaces

3. Facet-based
Exploratory
Search in
Topic Maps
Exploratory Search
M. Ueberall,
O. Drobnik
Introduction
Metrics
• Exploratory Search addresses information-seeking
Prototype
Comparison
problems where a user needs to find out something
Summary about a domain but lacks specific (a-priori) knowledge
• In this situation, the user will usually
• submit tentative queries
• explore the retrieved information
in order to selectively seek and passively obtain clues
about his next steps

4. Facet-based
Exploratory
Search in
Topic Maps
Faceted Classification
M. Ueberall,
O. Drobnik
Introduction
Metrics
Prototype • A Faceted Classification System enables
Comparison • the assignment of multiple classifications (called facets)
Summary to an object
• the flexible ordering of these classifications in multiple
ways w/o following pre-determined, taxonomic order
• A facet is a metadata attribute which should represent a
single important characteristic of the classified objects

5. Facet-based
Exploratory
Search in
Topic Maps
Facet-based Navigation as
M. Ueberall,
O. Drobnik
decision tree traversal
Introduction
Metrics
Prototype Country Novel
Sc` nes de la
e
Comparison Italy ... vie de Boh` me
e ...
Summary Contains Source of
La Boh` me
e La Boh` me
e
... Lucca (Leoncavallo) (Puccini)
Birthplace of Libretto by
Puccini, Giacomo Catalani, Alfredo Giacomo, Guiseppe Illica, Luigi
Composed Wrote libretto for
Tosca ... Illica, Luigi ...
By iteratively choosing a facet (and associated restriction
values), the information space is traversed

6. Facet-based
Exploratory
Search in
Topic Maps
Automated Facet Identification
M. Ueberall,
O. Drobnik
Introduction
Metrics
Prototype
• In the context of heterogenous, dynamically changing
Comparison
Summary
datasets new information has to be (re-)classified
on-the-fly
• In order to simplify the problem of missing/outdated
facet-based classifications, a generic heuristic is
needed

7. Facet-based
Exploratory
Search in
Topic Maps
Facet Identification
M. Ueberall,
Entity
O. Drobnik
Introduction
http://company.com
Metrics
Employer Employment
Employee
Prototype (website) (Employs/Employed by) (job)
Company Person Consultant/Programmer
Comparison (website)
Summary
http://product.com (Location) (Location)
http://www.frankfurt.de
Person entity
An entity is a subgraph of an information space, extracted
by taking all adjacent vertices (objects) of a given vertex
(subject)

8. Facet-based
Exploratory
Search in
Topic Maps
Facet Identification
M. Ueberall,
View
O. Drobnik
Introduction
Metrics
http://company.com
Prototype Employer Employee
Employment
(website) (Employs/Employed by) (job)
Comparison Company Person Consultant/Programmer
(website)
Summary
http://product.com (Location) (Location)
http://www.frankfurt.de
Company entity
Person entity
A view is a set of entities of an information space

9. Facet-based
Exploratory
Search in
Topic Maps
Facet Identification
M. Ueberall,
Facet
O. Drobnik
Introduction
Metrics http://company.com
Prototype Employer Employment
Employee
(website) (job)
(Employs/Employed by)
Comparison Company Person Consultant/Programmer
(website)
Summary
http://product.com (Location) (Location)
http://www.frankfurt.de
Company entity
Person entity
A facet is a set of equally labeled edges in a view

10. Facet-based
Exploratory
Search in
Topic Maps
Facet Identification
M. Ueberall,
Restriction Value
O. Drobnik
Introduction
Metrics http://company.com
Prototype Employer Employment
Employee
(website) (Employs/Employed by) (job)
Comparison Company Person Consultant/Programmer
(website)
Summary
http://product.com (Location) (Location)
http://www.frankfurt.de
Company entity
Person entity
The set of objects connected to a facet represent the
restriction values

11. Facet-based
Exploratory
Search in
Topic Maps
Navigation Metrics
M. Ueberall,
Balance
O. Drobnik
Introduction
Metrics
Prototype
Comparison
Idea:
• the balance of a facet indicates its na-
Country Novel
Sc` nes de la
e
Italy ... ...
Summary Contains
La Boh` me
e
vie de Boh` me
e
Source of
La Boh` me
e
... Lucca (Leoncavallo) (Puccini)
vigation efficiency (cf. tree traversal) Tosca
Puccini, Giacomo
Composed
Birthplace of
...
Catalani, Alfredo
Illica, Luigi
Giacomo, Guiseppe
Libretto by
Wrote libretto for
...
Illica, Luigi
Computation:
• determine the (non-linear) normalised variance of the
number of subjects for each object

12. Facet-based
Exploratory
Search in
Topic Maps
Navigation Metrics
M. Ueberall,
Cardinality
O. Drobnik
Introduction
Metrics
Prototype
Idea:
Comparison • a suitable facet has a limited amount of restriction
Summary values to choose from
Computation:
• determine the number of different objects (restriction
values) for each facet
• normalise result using a function based on the
gaussian density (cf. bell-shaped curve)

13. Facet-based
Exploratory
Search in
Topic Maps
Navigation Metrics
M. Ueberall,
Frequency
O. Drobnik
Introduction
Metrics Idea:
Prototype
• suitable facets occur frequently inside the collection
Comparison
Summary
• the more distinct concepts are covered, the more useful
the respective facet is in dividing the information space
Computation:
• determine the number of subjects in the dataset for
which the facet has been defined
• normalise result as a fraction of the total number of
subjects

14. Facet-based
Exploratory
Search in
Topic Maps
Navigation Metrics
M. Ueberall,
Example (1)
O. Drobnik
Introduction
http://company.com
Metrics
Employer Employment
Employee
Prototype (website) (Employs/Employed by) (job)
Company Person Consultant/Programmer
Comparison (website)
Summary http://product.com (Location) (Location)
http://www.frankfurt.de
Company entity
Person entity
facet balance(f) card(f) freq(f) score
Employment 1.0 0.72615 1.0 0.72615
(website) 1.0 0.72615 0.5 0.36308
(job) 1.0 0.0 0.5 0.0
(location) 1.0 0.0 1.0 0.0

15. Facet-based
Exploratory
Search in
Topic Maps
Navigation Metrics
M. Ueberall,
Example (2)
O. Drobnik
Introduction
Metrics http://company.com
Employer Employee
Prototype (website) Employment
(job)
(Employs/Employed by)
Company Person Consultant/Programmer
Comparison (website)
Summary http://product.com (Location) (Location)
http://www.frankfurt.de
facet balance(f) card(f) freq(f) score
Employment 1.0 0.72615 0.33333 0.24205
(website) 0.9 0.78270 0.5 0.35222
(job) 1.0 0.72615 0.33333 0.24205
(location) 0.9 0.78270 0.5 0.35222

16. Facet-based
Exploratory
Search in
Topic Maps
Additional Facet Classes
M. Ueberall,
O. Drobnik
Introduction
• Basic requirements of a facet browser:
Metrics
• present the instances of all available types
Prototype
• the relations need to be made explicit, selectable
Comparison
Summary
• Previous example focused on relations between topics:
• association types
• occurrence types
• Exploratory Search is also about filtering:
• topic types
• association roles types
• scope (scoping topics)

17. Facet-based
Exploratory
Search in
Topic Maps
Prototype
M. Ueberall,
O. Drobnik
Introduction
Metrics
Prototype
Comparison
Summary
based on the /facet user
interface [Hildebrand et al.
2006]
Objectives:
• support both TMAPI1 and TMAPI2 interfaces
• provide light-weight module for multiple query engines

18. Facet-based
Exploratory
Search in
Topic Maps
Topic Map Exploration
M. Ueberall,
“Classic” generic views
O. Drobnik
Introduction
Metrics
Associations (18) Internal Occurrences (4)
Born in Bibliography
Prototype Lucca Budde n, Julia n: quot;P uccini: His Life a nd W o rk squot;, O x ford Unive rsity P re ss (O x fo rd, 2002)
Composed Sa die , Sta nle y (e d): quot;P uccini a nd His O pe ra squot;, Ma cm illa n (Lo ndo n, 2000)
Comparison La Bohèm e
Edgar
Date of birth
1858-12-22
La fanciulla del W est Date of death
Gianni Schicchi
Summary Madam a Butterfly
1924-11-29
Manon Lescaut External Occurrences (12)
La rondine Article
Suor Angelica http://en.wikipedia.org/wiki/Giacom o_Puccini - Scope: Web; Wikipedia
Il Tabarro http://localhost:8080/operam ap/occurs/snl/puccini.htm - Scope: Local; Store Nors ke Leks ikon
Tosca http://www.ontopia.net/topicm aps/exam ples/opera/occurs/snl/puccini.htm - Scope: Store Nors ke Leks ikon; Web
Turandot
Gallery
Le Villi
http://localhost:8080/operam ap/occurs/puccini-gallery.htm - Scope: Local
Died in
Illustration
Brussels
http://localhost:8080/operam ap/occurs/com poser/puccini.gif - Scope: Local
Exponent of
Sound clip
verism o
http://www.puccini.it/files/vocepucc.wav - Scope: Centro s tudi Giacomo Puccini; Italian; Web
Pupil of
Web page
Angeloni, Carlo
http://localhost:8080/operam ap/occurs/hnh-puccini.htm - Scope: Local; Naxos
Bazzini, Antonio
http://www.naxos.com /com poser/btm .asp?fullnam e=Puccini,%20Giacom o - Scope: Naxos ; Web
Ponchielli, Am ilcare
http://www.operone.de/kom ponist/puccini.htm l - Scope: Web
http://www.r-ds.com /opera/pucciniana/gallery.htm - Scope: OperaRes ource; Web
Web site
(a) (b) http://www.landofpuccini.com
http://www.puccini.it - Scope: Centro s tudi Giacomo Puccini; Italian; Web

19. Facet-based
Exploratory
Search in
Topic Maps
Topic Map Exploration
M. Ueberall,
Stylized, facet-based display
O. Drobnik
Introduction
Metrics score=0.72614
Prototype http://www.landofpuccini.com
score=0.78270
http://www.puccini.it
Comparison
http://en.wikipedia/. . .
score=0.98012
http://localhost:8080/. . .
Summary Web site
http://www.ontopia.net/. . .
La Boh` me
e Article
Edgar Composed by
La fanciulla del West (Composed)
Puccini, Giacomo
Gianni Schicchi Work Composer
Madame Butterfly
... Web page
score=0.83527
Bibliography
score=0.72614 http://localhost:8080/. . .
http://www.noxos.com/. . .
http://www.r-ds.com/. . .
Budden, Julian: “Puccini. . .
http://www.operone.de/. . .
Sadie, Stanley (ed): “Puccini. . .

20. Facet-based
Exploratory
Search in
Topic Maps
Topic Map Exploration
M. Ueberall,
Selection tree and resulting tolog query
O. Drobnik
Introduction
Giacosa, Guiseppe
Metrics
Prototype
Libretto by
$A
Comparison
Summary $X Audio recording ...
Composed by
$B $C
... Born in ... Located in Italy
[Omnigator] Query results http://localhost:8080/omnigator/plugins/tolog/query.jsp?codeexample=exR
Query: A B C X
libretto-by($X : opera, giacosa : librettist), 5 56301 2 Puccini, Giacomo Lucca Manon Lescaut
audio-recording($X, $A), OPD-1265 Catalani, Alfredo Lucca Loreley
composed-by( $X : work, $B : composer), 423 567-2 Puccini, Giacomo Lucca Madama Butterfly
born-in( $B : person, $C : place), 7 47175 8 Puccini, Giacomo Lucca Tosca
located-in($C : containee, italy : container)?

21. Facet-based
Exploratory
Search in
Topic Maps
Perspectives
M. Ueberall,
O. Drobnik
Introduction
Metrics
• Navigation process for large information spaces can be
Prototype
Comparison
improved by reducing the initial number of different
Summary facets associated with a view
• Additional metrics: concept of semantic distance
between vertices [Andres/Naito2008]
• Minimal sub-graph of a given list of interested topics as
starting point [Dichev/Dicheva/Fischer2007]

22. Facet-based
Exploratory
Search in
Topic Maps
Summary and Outlook
M. Ueberall,
O. Drobnik
Introduction • The presented exploratory search interface for topic
Metrics maps may enhance existing navigation aids
Prototype
• It can be used to construct queries just by following
Comparison
Summary
links between concepts of interest, regardless of the
underlying query engine/legend
• A stand-alone, TMAPI1/TMAPI2 based implementation
with both basic text-based and graphical interfaces will
be available shortly
• Currently, the forementioned functionality is being
integrated in the user interface of an Eclipse based
prototype for software engineering support

23. Facet-based
Exploratory
Search in
Topic Maps
M. Ueberall,
O. Drobnik
Introduction
Metrics
Prototype
Comparison
Summary
Thank you!
e-mail to:
ueberall@tm.informatik.uni-frankfurt.de

24. Facet-based
Exploratory
Search in
Topic Maps
Example scenario in LTM notation
M. Ueberall,
O. Drobnik
[employer = quot;Employerquot;]
Introduction [employee = quot;Employeequot;]
Metrics [employment = quot;Employmentquot;
Prototype
= quot;Employsquot; / employer = quot;Employed byquot; / employee]
Comparison
employment([person = quot;Personquot;] : employee,
Summary
[company = quot;Companyquot;] : employer)
[website = quot;Websitequot;]
[location = quot;Locationquot;]
[job = quot;Jobquot;]
{company, website, quot;http://company.com/quot;} ∼ company-website
{company, website, quot;http://product.com/quot;} ∼ product-website
{company, location, quot;http://www.frankfurt.dequot;} ∼ company-location
{person, location, quot;http://www.frankfurt.dequot;} ∼ person-location
{person, job, [[consultant/programmer]]} ∼ person-job

25. Facet-based
Exploratory
Search in
Topic Maps
Merging heterogenous topic maps
M. Ueberall,
Bibliography example
O. Drobnik
Introduction
Metrics
[kcc_title = quot;The Knowledge-Creating Companyquot;]
Prototype [kcc_year = quot;1995quot;]
Comparison [nonaka = quot;Ikujiro Nonakaquot;]
Summary [takeuchi = quot;Hirotaka Takeuchiquot;]
reference( kcc_title :title, book :bibtype, kcc_year :year,
nonaka :author, takeuchi :author )
[kcc :book = quot;The Knowledge-Creating Companyquot;]
{ kcc, author, [[Ikujiro Nonaka]] }
{ kcc, author, [[Hirotaka Takeuchi]] }
{ kcc, year, [[1995]] }

26. Facet-based
Exploratory
Search in
Topic Maps
How to combine different scopes?
M. Ueberall,
O. Drobnik
Introduction • Problem of lack of formal semantics [Garshol2008]
Metrics
Prototype • A user must get an explanation/decide how scoping
Comparison topics are handled (and/or problem)
Summary
• Concepts from views of different scope can be handled
in two ways:
• list only valid concepts using quot;mergedquot; scope
• individual concepts retain their original scope
• Either way, facets representing scoping topics cannot
easily be handled like other classes of facets (i.e., user
cannot be shielded from representational details)