1. Semantic Web Techniques for Personalization of eGovernment Services
SemWAT 2006
1st International ER Workshop on Semantic Web Applications: Theory and Practice Tucson, AZ, November 2006
Semantic Web Techniques for Personalization of eGovernment Services
Federica Mandreoli
Riccardo Martoglia
Enrico Ronchetti
Paolo Tiberio
Università degli Studi di
Modena e Reggio Emilia
Fabio Grandi
Maria Rita Scalas
Università degli Studi di Bologna

2. Overview
Our research activities concern the implementation of Web information systems for eGovernment applications
Development of eGovernment initiatives: more and more on-line resources and services are being made available by Public Administrations (PAs)
We make use of temporal database and semantic Web techniques to provide personalized access to such resources and services
In particular, we consider multi-version norm texts (stored in XML format) available in Web repositories
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

3. Importance of versioning
Temporal concerns are ubiquitous in the law domain
Each normative text changes in time due to different modifications, but keeps its identity
The ability to model temporal dimensions is essential for the management of evolving norms
it is crucial to reconstruct the consolidated version of a norm
also past versions are still important
Original normative text 1 2
new version 3
new version
time
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

4. Importance of versioning
Applicability (semantic) versioning also plays an important role
some norms or some of their parts have or acquire a limited applicability
personalized version of the norm
A version only containing articles which are applicable to a citizen’s personal case
Art. 1 (unemployed)
xxy yyx yxyx yyyxx xyyx
Art. 2 (self-employed)
aab bbab abab abba ab
Art. 3 (retired)
qwqq ww wqqw wq ww
Self-employed
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

5. Motivation
Large XML collections of norms are made available by the PA on the Web but personalization is:
Absent, e.g. (temporal versioning partially supported)
Predefined in the Website structure and contents, e.g. (hardwired by human experts following the life-events approach)
Lack of an effective, flexible, on-demand (“intelligent”, efficient) personalization facility
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

6. Objectives
Development of an effective and efficient Web information system where:
norms are represented as XML documents
dynamics of norms in time is captured
limited applicability of norms (and their parts) is captured
selective access and reconstruction of versions is supported by a query engine
Aimed at:
enabling citizens to access personalized versions of multiversion resources
improving and optimizing the involvement of citizens in the eGovernance process
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

7. Personalized access to multi-version norms
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

8. The Technological Infrastructure
Public Administration DB
WEB SERVICES
OF PUBLIC
ADMINISTRATION 1
XML REPOSITORY OF ANNOTATED NORMS
SIMPLE
ELABORATION
UNIT 2
WEB SERVICES
WITH ONTOLOGY OC
creation /update
class Cx 3
Querying phase
1 – identification phase: reconstruction on-the-fly of the digital identity of the authenticated user
2 – classification phase: use of the collected digital identity to classify the citizen with respect to the civic ontology Oc
3 – querying phase: access and reconstruction of all and only norms which are applicable to the class Cx
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

9. Approach Definition of a temporal XML model including
a temporal multi-version XML schema
is based on the hierarchical organization of normative texts: contents-section-article-paragraph
at each level of the hierarchy, the history of changes is represented by the (time-stamped) versions produced
it supports ancestor-descendant inheritance
temporal manipulation operations
Extension of the XML model with applicability annotations in order to support semantic versioning
Design, implementation and evaluation of system prototypes supporting the model
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

10. The temporal XML schema
Law
Num – R
Type – R
4 Temporal Dimensions:
Publication time
time of publication on the Official Journal
Validity time
time the norm is in force
Efficacy time
time the norm can be applied
Transaction time
time the norm is stored in the system
Publication – R
Vt_Start – R
Vt_End – O
Tt_Start – R
Tt_End – O
Et_Start – R
Et_End – O
Title
Contents
Vt_Start – R
Vt_End – O
Tt_Start – R
Tt_End – O
Et_Start – R
Et_End – O TA
An_ref – O
Ver
Num – R
Section
Num – R
Vt_Start – R
Vt_End – O
Tt_Start – R
Tt_End – O
Et_Start – R
Et_End – O TA
An_ref – O
Ver
Num – R
Heading
Article
Num – R
Vt_Start – R
Vt_End – O
Tt_Start – R
Tt_End – O
Et_Start – R
Et_End – O TA
An_ref – O
Ver
Num – R
Heading
Paragraph
Num – R
Vt_Start – R
Vt_End – O
Tt_Start – R
Tt_End – O
Et_Start – R
Et_End – O TA
An_ref – O
Ver
Num – R
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

11. Semantic versioning
Extension of the multi-version model based on temporal dimensions to include a semantic versioning dimension to provide personalized access to norm texts
Civic ontology: a classification of citizens based on the distinctions introduced by successive norms (founding acts) that imply some limitations in their applicability
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

12. Semantic versioning
At this stage of the project, we manage “tree-like” ontologies
class taxonomies induced by the IS-A relationship
we exploit the pre-order and post-order properties of trees
New versioning dimension: applicability of different parts of a norm text to the relevant classes of the civic ontology
Applicability annotations (AA) are added to semantic versions
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

13. Semantic versioning
Applicability is inherited by descendant nodes unless locally redefined
By means of redefinitions we can also introduce, for each part of a document, complex applicability properties
Restrictions with respect to ancestors
Extensions with respect to ancestors
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

14. Example of full search John Smith is a self-employed citizen.
He is interested in the text of all the norms ...
... which contain paragraphs dealing with health care, ...
... which were valid and in effect between 2002 and 2004, ...
... and which are applicable to his case (civic class 7).
Structural constraint
Textual constraint
Temporal constraint
Applicability constraint
4 orthogonal constraints
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

15. Example of full search Structural constraint Textual constraint
FOR $a IN norms
WHERE textConstr ($a//paragraph//text(), ’health AND care’)
AND tempConstr (’vTime OVERLAPS PERIOD(’ ’,’ ’)’)
AND tempConstr (’eTime OVERLAPS PERIOD(’ ’,’ ’)’)
AND applConstr (’class 7’)
RETURN $a
Structural constraint
Textual constraint
Temporal constraint
Applicability constraint
4 orthogonal constraints
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

16. norm//paragraph//text()
Example of full search
Civic ontology
Normative DB
Norm
Article 1
Article 2 TA
Ver 1
AA=3
Par 1
Par 2 …
norm//paragraph//text() TA TA
Ver 1 TA
Ver 2
Ver 1
AA=4
‘class 7’ …
AA=3,8 AA
Health care…
…text X
Public health…
…text Y
Health care…
…text Z
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

17. Our prototype system (“native” approach)
The query engine is able to access and retrieve only the strictly necessary data
selection relies on ad-hoc data structures supporting multi-versioning
storage granularity is finer than the entire documents used by standard XML engines
Only the parts which satisfy the temporal and applicability constraints are used for the reconstruction of the retrieved documents
There is no need to retrieve whole XML documents and build space-consuming structures such as DOM trees
Enhanced query processing efficiency
Reduced memory requirements
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

18. Evaluation benchmark Three XML document sets Variable document size
5000 documents (120MB)
10000 documents (240MB)
20000 documents (480MB)
Variable document size
min = 2KB
avg = 24KB
max = 125KB
Five different query types
Queries on keywords (structural + textual constraints)
Q1 – keywords in contents
Q2 – keywords in type and contents
Temporal queries (structural + temporal constraints)
Q3 – conditions on publication, validity and transaction time
Mixed queries (structural + textual + temporal constraints)
Q4, Q5 – with keywords and temporal conditions
PERSONALIZATION OF THE QUERIES
Five variants with semantic constraints
Qx-A – with additional applicability constraints
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

19. Performance evaluation
Very high personalization query efficiency
The system is able to solve personalization problems by means of simple comparisons involving pre-post encodings
0.5-1% more time than for the original versions
3-4% storage space overhead
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

20. Performance evaluation
time
1741 msec
1366 msec
1046 msec
5000 docs
10000 docs
20000 docs
Scalability tests
The computing time grows sublinearly with the number of documents
Good scalability of the system in every type of query context
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

21. Conclusions
We presented our research work concerning the design and implementation of efficient Web-based information systems for eGovernment applications
We introduced a personalized access to resources on the basis of the digital identity of citizens relying on semantic versioning and ontology mapping
We developed a efficient platform (“native” approach) for which a specialized Multi-version XML Query Processor has been designed and implemented
We proved our approach to be very efficient in a large set of experimental situations and showed excellent scale-up figures with varying load configurations
SemWAT Semantic Web Techniques for Personalization of eGovernment Services

22. Future Work Extensions of the current framework
more advanced application requirements may include a more sophisticated ontology definition, possibly versioned, and more advanced reasoning services
Development of a complete technological infrastructure usable in a large Web-based eGovernment scenario, including
identification, classification and reconstruction services
Assessment of our prototype systems in a concrete working environment
with real users and with a large repository of real norms
Extension to a more general application domain (Web personalization via ontology-based user profiling)
SemWAT Semantic Web Techniques for Personalization of eGovernment Services