Overview

1. Overview • Our research activities concern the implementation of Web information systems for eGovernment applications • Due to 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

2. new version new version Original normative text time 1 2 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 versionsare still important

3. 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 versionof the norm • A version only containing provisions 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

4. Motivation • Large XML collections of norms are made available by the PA on the Web but personalizationis: • Absent, e.g. http://www.normeinrete.it(temporal versioning partially supported) • Predefined in the Website structure and contents, e.g. http://www.italia.gov.it(hardwired by human experts following the life-events approach) • Lack of an effective, flexible, on-demand (“intelligent”, efficient) personalization facility

5. Objectives • Development of an effective and efficientWeb information system where: • norms are represented as XML documents • dynamics of norms in time is captured • limited applicabilityof norms(and their parts) is captured • selective access and reconstruction of versionsis supported by a query engine • Aimed at: • enabling citizens to access personalizedversions of multiversion resources • improving and optimizing the involvement of citizens in the eGovernance process

6. XML REPOSITORY OF ANNOTATED NORMS 3 Querying phase The Technological Infrastructure Public Administration DB WEB SERVICES OF PUBLIC ADMINISTRATION 1 WEB SERVICES WITH ONTOLOGY OC 2 SIMPLE ELABORATION UNIT creation /update classCx 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

7. The Civic Ontology • Embodies a classification of citizens based on the distinctions introduced by successive norms that imply some limitations in their applicability (founding acts) • At this stage of the project, we manage “tree-like” ontologies(i.e. class taxonomies induced by the IS-A relationship)

8. The modeling approach • Extension of a previous temporal XML model (D&KE 2005) 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 • Addition of applicability annotations in order to support semantic versioning

9. Vt_Start – R Vt_End – O Tt_Start – R Tt_End – O Et_Start – R Et_End – O Vt_Start – R Vt_End – O Tt_Start – R Tt_End – O Et_Start – R Et_End – O Vt_Start – R Vt_End – O Tt_Start – R Tt_End – O Et_Start – R Et_End – O Vt_Start – R Vt_End – O Tt_Start – R Tt_End – O Et_Start – R Et_End – O TA TA TA TA Publication – R Vt_Start – R Vt_End – O Tt_Start – R Tt_End – O Et_Start – R Et_End – O The temporal XML schema Num – R Law 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 storedin the system Title Contents An_ref – O Ver Num – R Section Num – R An_ref – O Ver Num – R Num – R Heading Article An_ref – O Ver Num – R Heading Paragraph Num – R An_ref – O Ver Num – R

10. Semantic versioning • A pre-order and post-order numbering scheme is introduced in the tree-like ontology • Classes are identified by means of their pre-order code • Encoding is exploited in query processing for quick ancestor-descendant checking • Applicability annotations (AA) are added to semantic versions of document parts as references to the ontology classes

11. 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

12. 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 Semantic constraint 4 orthogonal constraints

13. Example of full search FOR $a IN norms WHERE textConstr ($a//paragraph//text(), ’health AND care’) AND tempConstr (’vTime OVERLAPS PERIOD(’2002-01-01’,’2004-12-31’)’) AND tempConstr (’eTime OVERLAPS PERIOD(’2002-01-01’,’2004-12-31’)’) AND applConstr (’class 7’) RETURN $a Structural constraint Textual constraint Temporal constraint Semantic constraint 4 orthogonal constraints

14. 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 TA Ver 1 Ver 1 Ver 2 AA=4 AA=3,8 ‘class 7’ … AA Health care… …text X Public health… …text Y Health care… …text Z

15. Enhanced query processing efficiency Reduced memory requirements 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 (including our previous prototype – “stratum” approach) • 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

16. Three XML document sets 5000 documents (120MB) 10000 documents (240MB) 20000 documents (480MB) Variable document size min = 2KB avg = 24KB max = 125KB PERSONALIZATION OF THE QUERIES Evaluation benchmark • 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 • Five variants with semantic constraints • Qx-A – with additional applicability constraints

17. Performance evaluation • The new system outperforms its predecessor (“stratum” approach) as far as temporal queries are concerned • The new system showed a very highefficiencyin personalization query processing • selection of qualifying versions is improved by a technique involving simple comparisons involving pre-post encodings • 0.5-1% more time than for the original versions • 3-4%storage space overhead • The new system showed good scalability figures in every type of query context • the computing time grows sublinearly with the number of documents (it depends mainly on the size of the results)

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

19. Future Work • Extensions of the current framework • more advanced application requirements may include a more sophisticated ontology definition (graph-like), possibly versioned, and more advanced reasoning services • Completion of the technological infrastructure usable in a large Web-based eGovernment scenario, including • identification and classification 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)