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Jesús M. Almendros-Jiménez, Antonio Becerra-Terón, Ginés Moreno, José A. Riaza,
Tuning Fuzzy SPARQL Queries in a Fuzzy Logic Programming Environment.
2019 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE 2019). [Electronic Edition].
We have recently designed FSA-SPARQL, an extension of the SPARQL query language for querying fuzzy RDF datasets. Answers of FSA-SPARQL queries are usually annotated with truth degrees which are computed from fuzzy connectives and operators that act on truth degrees associated to RDF triples. While FSA-SPARQL offers a rich repertoire of fuzzy connectives and operators, it is not always easy to retrieve the user’s expected answers. This is very often due to wrong formulation of queries, caused by inadequate use/combination of fuzzy connectives, operators and thresholds. For instance, a high threshold for truth degrees in some RDF datasets can lead to an empty set of answers, some strong or weak restrictive combination of fuzzy conditions might produce few or too many answers, etc. On the other hand, our research group has also developed the fuzzy logic programming language FASILL, which has been equipped with tuning techniques for enabling the customization of queries from test cases. In this paper, our goals are: (1) to provide a FSA-SPARQL translation to FASILL and (2) apply the tuning techniques to FSA-SPARQL queries for getting more precise formulation of queries from test cases.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón, Manuel Torres.
Integrating and Querying OpenStreetMap and Linked Open Data.
Computer Journal, Volume 62, Issue 3, March 2019, Pages 321–345. [Electronic Edition]
In recent years, Open Street Map (OSM) has evolved into a highly popular geospatial system. The key of success of OSM is that OSM is open to absolutely everyone. OSM is not dependent on any one government, company, university, or international organization. OSM is based on crowdsourcing, in which users collaborate to collect spatial data of urban and rural areas on the earth. With the arising of Linked Open Data (LOD) initiative, and more concretely with Linked Geo Open Data (LGOD), many Web resources have been made available to everyone, providing geo-located datasets. In this paper a framework, called XOSM (XQuery for OpenStreetMap), for integrating and querying OSM and LGOD resources is presented. The framework is equipped with a Web tool and a rich XQuery-based library, enabling the definition of queries combining OSM layers and layers created from LGOD resources (KML, GeoJSON, CSV and RDF (and also XML)). The framework also provides an API to execute XQuery queries using the library.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón, Gines Moreno.
Fuzzy Queries of Social Networks involving Sentiment Analysis and Topic Detection.
XVIII Jornadas de Programación y Lenguajes (PROLE 2018) [Electronic Edition]
Social networks have become a source of data which are of interest in all areas, and their querying and analysis is a hot topic in computer science. Our research group has developed a fuzzy extension of the Semantic Web query language SPARQL, called FSA-SPARQL (Fuzzy Sets and Aggregators based SPARQL). This extension provides mechanisms to express fuzzy queries against RDF data. FSA-SPARQL works with social networks. With this aim, FSA-SPARQL enables the transformation and fuzzification of social network API data. Fuzzification of social networks data is automatic and user-defined enabling a wide range of mechanisms for ranking and categorization, including sentiment analysis and topic detection. As case study, FSA-SPARQL has been used to query three well-known social networks: Twitter, Foursquare and TMDb
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
Analyzing the Tagging Quality of the Spanish OpenStreetMap.
ISPRS International Journal of Geo-Information, 2018, 7(8), 323 [Electronic Edition]
In this paper, a framework for the assessment of the quality of OpenStreetMap is presented, comprising a batch of methods to analyze the quality of entity tagging. The approach uses Taginfo as a reference base and analyses quality measures such as completeness, compliance, consistence, granularity, richness and trust . The framework has been used to analyze the quality of OpenStreetMap in Spain, comparing the main cities of Spain. Also a comparison between Spain and some major European cities has been carried out. Additionally, a Web tool has been also developed in order to facilitate the same kind of analysis in any area of the world.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón and Ginés Moreno.
Fuzzy Queries of Social Networks with FSA-SPARQL.
Experts Systems with Applications Journal, 2018, Volume 113, 15 December 2018, Pages 128-146. [Electronic Edition]
Social networks have become a source of data which are of interest in all areas, and their querying and analysis is a hot topic in computer science. Our research group has developed a fuzzy extension of the Semantic Web query language SPARQL, called FSA-SPARQL (Fuzzy Sets and Aggregators based SPARQL). This extension provides mechanisms to express fuzzy queries against RDF data. FSA-SPARQL works with social networks. With this aim, FSA-SPARQL enables the transformation and fuzzification of social network API data. Fuzzification of social networks data is automatic and user-defined enabling a wide range of mechanisms for ranking and categorization, including sentiment analysis and topic detection. As a case study, FSA-SPARQL has been used to query three well-known social networks: Twitter, Foursquare and TMDb.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
Property-based Testing of SPARQL queries.
Proceedings of the 16th International Symposium on Database Programming Languages (DBPL 2017). ACM Press [Electronic Edition]
IIn this paper we describe a property-based testing tool for SPARQL. Given a SPARQL query, the tool randomly generates test cases which consist on instances of an ontology. The tool checks the well typed-ness of the SPARQL query as well as the consistency of the test cases with the ontology axioms. With this aim, a type system has been defined for SPARQL. Test cases are later used to execute the SPARQL query. The output of the SPARQL query is tested with a Boolean property which is defined in terms of membership of ontology individuals to ontology classes. The testing tool reports counterexamples when the Boolean property is not satisfied.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
Type Checking and Property-based Testing of SPARQL queries.
Proceedings of the XVII Spanish Conference on Programming and Computer Languages (PROLE 2017) [Electronic Edition]
In this paper a property-based testing tool for SPARQL is described. The tool randomly generates test cases in the form of instances of an ontology. The tool checks the well typed-ness of the SPARQL query as well as the consistency of the test cases with the ontology axioms. Test cases are after used to execute queries. The output of the queries is tested with a Boolean property which is defined in terms of membership of ontology individuals to classes. The testing tool reports counterexamples when the Boolean property is not satisfied
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón and Ginés Moreno.
FSA-SPARQL: Fuzzy Queries in SPARQL.
Proceedings of the XVII Spanish Conference on Programming and Computer Languages (PROLE 2017) [Electronic Edition]
SPARQL has been adopted as query language for the Semantic Web. RDF and OWL have been also established as vocabularies to describe ontologies in this setting. While RDF/OWL/SPARQL have been designed for querying crisp information, some contexts require to manage uncertainty, vagueness and imprecise knowledge. In this paper we propose a SPARQL extension, called FSA-SPARQL (Fuzzy Sets and Aggregators based SPARQL) in which queries can involve different fuzzy connectives and (aggregation) operators. The language has been implemented as an extension of the ARQ Jena SPARQL engine and it is equipped with a Web tool from which queries can be executed on-line
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
A Web Tool for Type Checking and Testing of SPARQL Queries.
17 International Conference on Web Engineering (ICWE 2017), Springer, LNCS 10360, 2017 [Electronic Edition]
In this paper a property-based testing tool for SPARQL is described. The tool randomly generates test cases in the form of instances of an ontology. The tool checks the well typed-ness of the SPARQL query as well as the consistency of the test cases with the ontology axioms. Test cases are after used to execute queries. The output of the queries is tested with a Boolean property which is defined in terms of membership of ontology individuals to classes. The testing tool reports counterexamples when the Boolean property is not satisfied.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón and Ginés Moreno.
A Fuzzy Extension of SPARQL based on Fuzzy Sets and Aggregators.
FUZZ-IEEE 2017: The 2017 IEEE International Conference on Fuzzy Systems, 2017, pages 1-6, IEEE [Electronic Edition]
SPARQL has been adopted as query language for the Semantic Web. RDF and OWL have been also established as vocabularies to describe ontologies in this setting. While RDF/OWL/SPARQL have been designed for querying crisp information, some contexts require to manage uncertainty, vagueness and imprecise knowledge. In this paper we propose a SPARQL extension, called FSA-SPARQL (Fuzzy Sets and Aggregators based SPARQL) in which queries can involve different fuzzy connectives and (aggregation) operators. The language has been implemented as an extension of the ARQ Jena SPARQL engine and it is equipped with a Web tool from which queries can be executed on-line.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón and Alfredo Cuzzocrea.
Syntactic and Semantic Errors in SPARQL Queries.
Seventh edition of the International Workshop on Linked Web Data Management (LWDM), CEUR Workshop Proceedings, 2017 [Electronic Edition]
In this paper we present a tool to syntactically and semantically validate SPARQL queries. With this aim, we extract triple patterns and filter conditions from SPARQL queries and we use the OWL API and an OWL ontology reasoner in order to detect wrong expressions. Given an ontology and a query, the tool reports different kinds of programming errors: wrong use of vocabulary, wrong use of resources and literals, wrong filter conditions and wrong use of variables in triple patterns and filter conditions. When the OWL ontology reasoner is used the tool reports a diagnosis.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón
Automatic Property based Testing and Path Validation of XQuery Programs.
Software Testing, Verification and Reliability Journal, January-March, Willey InterScience, 2017. [Electronic Edition]
Property-based testing has gained popularity in recent years in many areas of software development. The specification of assertions/properties helps to understand the semantics of pieces of code and, in modern programming environments, it can serve to test the program behavior. In this paper an XQuery property- based testing tool is presented which enables to automatically test XQuery programs. The tool is able to systematically generate XML instances (i.e., test cases) from a given XML schema, and to filter XML instances with input properties specified by the programmer. Additionally, the tool automatically checks output (respectively, input-output) properties in each output instance (respectively, each pair of input-output instances). The tool is able to report whether the XQuery program passes the test, that is, if all the test cases satisfy the (input-)output property, as well as the number of test cases used for testing. In addition, if the XQuery program fails the test, the tool shows counterexamples found in the test cases. Properties are specified with XQuery Boolean functions, and the testing tool has been implemented in XQuery. Additionally, an XQuery path validation tool is presented. This tool is able to detect wrong paths in XQuery expressions. The path validation tool takes as input an XML Schema and it reports those paths on the XQuery program that do not match the XML Schema. The path validation tool is a complement to the testing tool rejecting XQuery programs that do not conform to the XML Schema. The path validation tool has been also implemented in XQuery. Finally, a Web tool has been developed enabling to test and validate XQuery programs.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón and Alfredo Cuzzocrea.
Syntactic and Semantic Validation of SPARQL Queries.
32nd ACM SIGAPP Symposium On Applied Computing (SAC 2017) ACM Press, 2017. [Electronic Edition]
In this paper we present a tool to syntactically and semantically validate SPARQL queries. With this aim, we extract triple patterns and filter conditions from SPARQL queries and we use the OWL API and an OWL ontology reasoner in order to detect wrong expressions. Given an ontology and a query, the tool reports different kinds of programming errors: wrong use of vocabulary, wrong use of resources and literals, wrong filter conditions and wrong use of variables in triple patterns and filter conditions. When the OWL ontology reasoner is used the tool reports a diagnosis.
Jesús M. Almendros-Jiménez and Antonio Becerra-Terón. T
Testing of ATL programs from Randomly Generated Ecore Test Models.
Proceedings of the XVI Spanish Conference on Programming and Computer Languages (PROLE 2016) [Electronic Edition]
Model transformation testing is crucial to detect incorrect transformations. Buggy transformations can lead to incorrect target models, either violating target meta-model requirements or more complex target model properties. In this paper we present a tool for testing ATL transformations. This tool is an extension of a previously developed tool for testing XML-based languages. With this aim an Ecore to XML Schema transformation is defined which makes to automatically generate random Ecore models possible. These randomly generated Ecore models are used to test ATL transformations. Properties to be tested are specified by OCL constraints, describing input and output conditions on source and target models, respectively.
esús M. Almendros-Jiménez and Antonio Becerra-Terón.
Automatic Generation of Ecore Models for Testing ATL Transformations.
Proceedings of the 6th International Conference on Model and Data Engineering, MEDI 2016, LNCS 9893, Almería, Spain, September 21-23, 2016, pages 16-30. [Electronic Edition]
Model transformation testing is crucial to detect incorrect transformations. Buggy transformations can lead to incorrect target models, either violating target meta-model requirements or more complex target model properties. In this paper we present a tool for testing ATL transformations. This tool is an extension of a previously developed tool for testing XML-based languages. With this aim an Ecore to XML Schema transformation is defined which makes to automatically generate random Ecore models possible. These randomly generated Ecore models are used to test ATL transformations. Properties to be tested are specified by OCL constraints, describing input and output conditions on source and target models, respectively.
Jesús M. Almendros-Jiménez and Antonio Becerra.
XQuery-Based Query Processing in Open Street Map.
Geographical Information Systems Theory, Applications and Management, Volume 582 of the series Communications in Computer and Information Science, pages 50-68, 2016. [Electronic Edition]
Volunteered geographic information (VGI) makes available a very large resource of geographic data. The exploitation of data coming from such resources requires an additional effort in the form of tools and effective processing techniques. One of the most established VGI is Open Street Map (OSM) offering data of urban and rural maps from the earth. In this paper we present a library for querying OSM with XQuery. This library is based on the well-known spatial operators defined by Clementini and Egenhofer, providing a repertoire of XQuery functions which encapsulate the search on the XML document representing a layer of OSM, and make the definition of queries on top of OSM layers easy. In essence, the library is equipped with a set of OSM Operators for OSM elements which, in combination with Higher Order facilities of XQuery, facilitates the composition of queries and the definition of keyword based search geo-localized queries. OSM data are indexed by an R-tree structure, in which OSM elements are enclosed by Minimum Bounding Rectangles (MBRs), in order to get shorter answer time.
Jesús M. Almendros-Jiménez and Antonio Becerra.
Automatic Validation of XQuery Programs.
The 17th International Conference on Information Integration and Web-based Applications & Services, ACM Press, 2015, Article 80. [Electronic Edition]
In this paper we present a tool for the automatic validation of XQuery programs. Firstly, the tool is able to detect wrong paths in XQuery expressions with respect to an XML Schema. Secondly, it makes possible the specification of in- put and output properties, as well as input-output properties (i.e., properties relating input and output data) of programs. Thirdly, the tool is able to filter randomly generated test cases with input properties, as well as to test output and input-output properties on randomly generated test cases and the corresponding output. It reports counterexamples when output or input-output properties are not satisfied. The tool has been implemented as an XQuery library which can be used from any XQuery interpreter.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón and Manuel Torres.
Aggregation Operators in Geospatial Queries for Open Street Map.
On the Move to Meaningful Internet Systems: OTM 2015 Conferences Proceedings. LNCS 9415, Springer 2015, pages 501-518. [Electronic Edition]
One of the most stablished Volunteered Geographic Information (VGI) systems is Open Street Map(OSM) offering data from the earth of urban and rural maps. Recently [1], we have presented a library for querying OSM data with the XML query language XQuery. This library is based on the well-known spatial operators defined by Clementini and Egenhofer, providing a repertoire of XQuery functions which encapsulates the search on the XML document representing a layer of OSM, and makes the definition and composition of queries on top of OSM layers easier. This paper goes towards the incorporation in the library of aggregation operators in order to be able to express queries involving data summarization and ranking. A rich repertoire of aggregation operators has been defined which, in combination with the previously proposed library, makes possible to easily formulate aggregation-based queries. Also we present a Web-based tool, called XOSM (XQuery for Open Street Map), developed in our group, that uses the proposed library to query and visualize OSM data.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
Property based Testing of XQuery Programs.
Proceedings of the XV Spanish Conference on Programming and Computer Languages (PROLE 2015). [Electronic Edition]
In this paper we present the elements of an XQuery testing tool which makes possible to automatically test XQuery programs. The tool is able to systematically generate XML instances (i.e., test cases) from a given XML schema. The number and type of instances is defined by the human tester. These instances are used to execute the given XQuery program. In addition, the tool makes possible to provide an user defined property to be tested against the output of the XQuery program. The property can be specified with a boolean XQuery function. The tool is implemented as a oracle able to report whether the XQuery program passes the test, that is, all the used test cases satisfy the property, as well as the number of test cases used for testing. In the case of the XQuery program fails in the testing, the tool shows counterexamples found from the test cases. The tool has been implemented as an XQuery library which makes possible to be used from any XQuery interpreter.
Jesús M. Almendros-Jiménez and Antonio Becerra-Terón.
Distance based Queries in Open Street Map.
2nd International Workshop on NoSQL Databases, Emerging Database Technologies and Applications. DEXA Workshops. IEEE, pp. 2535-2539, 2015. [Electronic Edition]
Volunteered geographic information (VGI) makes available a very large resource of geographic data. The exploitation of data coming from such resources requires an additional effort in the form of tools and effective processing techniques. One of the most stablished VGI is Open Street Map (OSM) offering data of urban and rural maps from the earth. Recently [1], we have presented a library for querying OSM data with the XML query language XQuery. This library is based on the well-known spatial operators defined by Clementini and Egenhofer, providing a repertoire of XQuery functions which encapsulate the search on the XML document representing a layer of OSM, and make the definition and composition of queries on top of OSM layers easier. In this paper, we will show how to extend the library in order to express distance based queries. Distances will be used either to get layers of objects in a certain distance from a given object, or to express queries involving closeness concepts.
Jesús M. Almendros-Jiménez and Antonio Becerra-Terón.
XQuery Testing from XML Schema based Random Test Cases.
Proceedings of the 26th International Conference on Database and Expert Systems Applications, DEXA Springer, LNCS 9262, pages 268-282, 2015. [Electronic Edition]
In this paper we present the elements of an XQuery testing tool which makes possible to automatically test XQuery programs. The tool is able to systematically generate XML instances (i.e., test cases) from a given XML schema. The number and type of instances is defined by the human tester. These instances are used to execute the given XQuery program. In addition, the tool makes possible to provide an user defined property to be tested against the output of the XQuery program. The property can be specified with a Boolean XQuery function. The tool is implemented as an oracle able to report whether the XQuery program passes the test, that is, all the test cases satisfy the property, as well as the number of test cases used for testing. In the case of the XQuery program fails the testing, the tool shows counterexamples found in the test cases. The tool has been implemented as an XQuery library which makes possible to be used from any XQuery interpreter.
Jesús M. Almendros-Jiménez and Antonio Becerra.
Querying Open Street Map with XQuery.
1st International Conference on Geographical Information Systems Theory, Applications and Management, GISTAM 2015. pages 61-71, ScitePress. [Electronic Edition]
In this paper we present a library for querying Open Street Map (OSM) with XQuery. This library is based on the well-known spatial operators defined by Clementini and Egenhofer, providing a repertoire of XQuery functions which encapsulate the search on the XML document representing a layer of OSM, and make the definition of queries on top of OSM layers easy. In essence, the library provides a repertoire of OSM Operators for points and lines which, in combination with Higher Order facilities of XQuery, facilitates the composition of queries and the definition of keyword based search geo-localized queries. OSM data are indexed by an R-tree structure, in which points and lines are enclosed by Minimum Bounding Rectangles (MBRs), in order to get shorter answer time.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón, and Francisco García-García.
XPath for Querying GML-Based Representation of Urban Maps.
B. Murgante et al. (Eds.): ICCSA 2011, Part I, LNCS 6782, pp. 177–191, 2011. Springer-Verlag. [Electronic Version]
Geography Markup Language (GML) has been established as the standard language for the transport, storage and modelling of geographic information. In this paper we study how to adapt the XPath query language to GML documents. With this aim, we have defined a XPath based query language which handles the “semantic structure” of GML. Our approach focuses on querying urban maps whose representation is based on GML. We have developed a system called UALGIS, in order to implement the approach. Such system stores GML documents by means of the PostGIS RDBMS. In order to execute semantic-based XPath queries we have defined a translation of the queries into SQL. Such translation takes into account the GML schema. Finally, the system allows to visualize the result. With this aim, the result of a query is exported to the Keyhole Markup Language (KML) format.
Jesús M. Almendros Jiménez, Antonio Becerra Terón and Francisco García-García.
Development of a Query Language for GML based on XPath.
6th International Workshop on Automated Specification and Verification of Web Systems, WWv 2010, Vienna, Austria, 2010.[pdf]
Geography Markup Language (GML) has been established as the standard language for the transport, storage and modeling of geographic information. In this paper we study how to adapt the XPath query language to GML documents. With this aim, we have defined a semantic based XPath language which is not based on the {\it (tree-based) syntactic structure of GML documents, instead it is based on the ``semantic structure'' of GML documents. In other words, the proposed XPath language is based on the GML schema. We have developed a system called UALGIS, in order to implement the approach. Such system stores GML documents by means of the PostGIS RDBMS. In order to execute semantic-based XPath queries we have defined a translation of the queries into SQL. Such translation takes into account the GML schema. Finally, the system allows to visualize the result. With this aim, the result of a query is exported to the Keyhole Markup Language (KML) format.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón and Francisco Javier Enciso-Baños.
Integrating XQuery and Logic Programming.
Proceedings of the 17th International Conference on Aplications of Declarative Programming and Knowledge Management, INAP’07 and 21th Workshop on (Constraint) Logic Programming, WLP’07, D. Seipel, M. Hanus, and A. Wolf (Eds.) Lecture Notes in Artifical Intelligence 5437, pages 117–135, Springer-Verlag, 2009.[Electronic Version]
In this paper we investigate how to integrate the XQuery language and logic programming. With this aim, we represent XML documents by means of a logic program. This logic program represents the document schema by means of rules and the document itself by means of facts. Now, XQuery expressions can be integrated into logic programming by considering a translation from for-let-where-return expressions into logic rules and a goal.
Jesús M. Almendros Jiménez, Antonio Becerra Terón and Francisco Javier Enciso Baños.
Querying XML Documents in Logic Programming.
Journal of Theory and Practice of Logic Programming, 8(3), 323-361, Elsevier Science, 2008. [Electronic Version]
Extensible Markup Language (XML) is a simple, very flexible text format derived from SGML. Originally designed to meet the challenges of large-scale electronic publishing, XML is also playing an increasingly important role in the exchange of a wide variety of data on the Web and elsewhere. XPath language is the result of an effort to provide address parts of an XML document. In support of this primary purpose, it becomes in a query language against an XML document. In this paper we present a proposal for the implementation of the XPath language in logic programming. With this aim we describe the representation of XML documents by means of a logic program. Rules and facts can be used for representing the document schema and the XML document itself. In particular, we will present how to index XML documents in logic programs: rules is supposed to be stored in main memory, however facts are stored in secondary memory by using two kind of indexes: one for each XML tag, and other for each group of terminal items. In addition, we study how to query by means of the XPath language against a logic program representing an XML document. It evolves the specialization of the logic program with regard to the XPath expression. Finally, we will also explain how to combine the indexing and the top-down evaluation of the logic program.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón and Francisco Javier Enciso-Baños.
Magic Sets for the XPath Language.
Journal of Universal Computer Science, Vol. 12, No. 11, pp. 1651-1678, 2006. [Electronic Edition]
The eXtensible Markup Language (XML) is considered as the format of choice for the exchange of information among various applications on the Internet. Since XML is emerging as a standard for data exchange, it is natural that queries among applications should be expressed as queries against data in XML format. This use gives rise to a requirement for a query language expressly designed for XML resources. World Wide Web Consortium (W3C) convened to create the XQuery language, concretely, a typed functional language for querying XML documents. One key aspect of the XQuery language is the use of the XPath language as basis for handling the structure of an XML document. In this paper, we present a proposal for the representation of XML documents by means of a logic program. Rules and facts can be used for representing the document schema and the XML document itself. In addition, we study how to query by means of the XPath language against a logic program representing an XML document. It evolves the specialization of the logic program with regard to the XPath expression. This specialization technique is based on the well-known transformation technique called Magic Sets and studied for deductive databases. The b ottom-up evaluation of the sp ecialized program is used for answering the query in the XPath language.
Jesus M. Almendros Jimenez, Antonio Becerra Teron, Francisco Javier Enciso Baños.
XQuery within Logic Programming.
Proceedings of the VI Jornadas de Programación y Lenguajes, PROLE’06, pages 171-194, Ed. Paqui Lucio y Fernando Orejas, Sitges, Barcelona, 2006, ISBN: 84-95999-84-6.[pdf]
XQuery is a typed functional language for Web Databases. It is a query language against XML documents. In this paper we study how to translate XQuery programs into logic programming. With this aim, each XQuery functional expression is translated into logic rules and goals. The answers for the goals correspond with answers for the query against XML documents.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
Database Query Languages and Functional Logic Programming.
ournal of New Generation Computing, 24(2), pages 129-184, 2006. [Electronic Edition]
Functional logic programming is a paradigm which integrates functional and logic programming. It is based on the use of rewriting rules for defining of programs, and rewriting for goal solving. In this context, goals, usually, consist of equality (and, sometimes, inequality) constraints, which are solved in order to obtain answers, represented by means of substitutions. On the other hand, database programming languages involve a data model, a data definition language and, finally, a query language against the data defined according to the data model. To use functional logic programming as database programming language, (1) we will propose a data model involving the main features adopted from functional logic programming (for instance, handling of partial and infinite data), (2) we will use conditional rewriting rules as data definition language, and finally, (3) we will deal with equality and inequality constraints as query language. Moreover, as most database systems, (4) we will propose an extended relational calculus and algebra, which can be used as alternative query languages in this framework. Finally, (5) we will prove that three alternative query languages are equivalent.
Jesús M. Almendros Jiménez, Antonio Becerra Terón and Francisco Javier Enciso-Baños.
Magic Sets for the XPath Language.
Proceedings of the V Jornadas de Programación y Lenguajes, PROLE'05, integrated in the CEDI conference. Ed. Francisco López Fraguas, Thompson Paraninfo, pages 211-220, 2005.[pdf]
The eXtensible Markup Language (XML) is considered as the format of choice for the exchange of information among various applications on the Internet. Since XML is emerging as a standard for data exchange, it is natural that queries among applications should be expressed as queries against data in XML format. This use gives rise to a requirement for a query language designed expressly for XML resources. World Wide Web Consortium (W3C) convened to create the XQuery language, concretely, a typed functional language for querying XML documents. One key aspect of the XQuery language is the use of the XPath language as basis for handling of the structure of a XML document. In this paper we present a proposal for the representation of XML documents by means of a logic program. Rules and facts can be used for representing the document schema and the XML document itself. In addition, we study how to query by means of the XPath language against a logic program representing a XML document. It evolves the specialization of the logic program with regard to the XPath expression. This specialization technique is based on the well-known transformation technique called Magic Sets and studied for deductive databases. The bottom-up evaluation of the specialized program is used for answering the query in the XPath language.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
A Safe Relational Calculus for Functional Logic Deductive Databases.
Electronic Notes on Theoretical Computer Science, 86(3), 47 pages, Elsevier Science, 2003. [Electronic Edition]
In this paper, we present an extended relational calculus for expressing queries in functional-logic deductive databases. This calculus is based on first-order logic and handles relation predicates, equalities and inequalities over partially defined terms, and approximation equations. For the calculus formulas, we have studied syntactic conditions in order to ensure the domain independence property. Finally, we have studied its equivalence w.r.t. the original query language, which is based on equality and inequality constraints.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
A Relational Algebra for Functional Logic Deductive Databases.
Proceedings of the 5th International Conference on Perspectives of System Informatics, PSI'03, Manfred Broy and Alexandre V. Zamulin Eds, Lecture Notes in Computer Science no. 2890, pp. 494-508, Springer Verlag, 2003.[Electronic Edition]
In this paper, we study the integration of functional logic programming and databases by presenting a data model, and a query and data definition language. The query and data definition language is based on the use of a set of algebra operators over an extended relational algebra. The algebra expressions built from the extended algebra are used for expressing queries and rules. In addition, algebra expressions can be used for defining functions, typical in a functional logic program.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
A Safe Relational Calculus for Functional Logic Deductive Databases.
Proceedings of the International Workshop on Functional and (Constraint) Logic Programming, WFLP'03, Ed. G. Vidal, Technical Report DSIC-II/13/03, pp. 212-226, 2003.[pdf]
In this paper, we present an extended relational calculus for expressing queries in functional-logic deductive databases. This calculus is based on first-order logic and handles relation predicates, equalities and inequalities over partially defined terms, and approximation equations. For the calculus formulas, we have studied syntactic conditions in order to ensure the domain independence property. Finally, we have studied its equivalence w.r.t. the original query language which is based on equality and inequality constraints.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
A Safe Calculus and Algebra for Querying Functional Logic Deductive Databases.
Proceedings of the Segundas Jornadas de Programación y Lenguajes, PROLE'02, Ed. R. Peña, A. Herranz, J.J. Moreno, pp. 71-86, 2002. [pdf]
In this paper, we present an extended relational calculus and algebra for a functional logic deductive database language. The extended relational calculus is based on the relational first-order logic, by adding constraints in the form of equalities and disequalities over complex (partially defined and possibly infinite) values and interpreted functions. In addition, we propose the notion of safety over calculus formulas in order to guarantee the property of domain independence. In the case of the extended relational algebra, we provide a generalization of the selection and projection operators in order to restructure complex values by means of constructors and destructors, interpreted functions and function inverses, as well as, to consider equality and disequality constraints. Finally, we will state that the two query formalisms (calculus and algebra) are equivalent.
Jesús Manuel Almendros Jiménez, Antonio Becerra Terón and Jaime Sánchez Hernández.
A Computational Model for Functional Logic Deductive Databases.
Proceedings of the 17th Intenational Conference on Logic Programming, ICLP'01, Ed. Ph. Codognet, Lecture Notes in Computer Science no. 2237, pp. 331-347, Springer Verlag, 2001.[Electronic Edition]
This paper adds the handling of negative information to a functional-logic deductive database language. By adopting as semantics for negation the so-called CRWLF, wherein the negation is intended as 'finite failure' of reduction, we will define Herbrand algebras and models for this semantics and a fix point operator to be used in a new goal-directed bottom-up evaluation mechanism based on magic transformations. This bottom-up evaluation will simulate the top-down one of the original program; in fact, it will carry out a goal-directed lazy evaluation.
Jesús M. Almendros-Jiménez, Antonio Becerra-Terón.
Framework for Goal-DirectedBottom-Up Evaluation of Functional-logic Programs.
Proceedings of the Fifth International Functional and Logic Programming Symposium, FLOPS'01, Eds. H. Kuchen, W. Ueda, Lecture Notes in Computer Science, no. 2024, pp. 153-169, Springer Verlag, 2001 [Electronic Edition]
In this paper we start the design of a functional-logic deductive database language. Given that most logic deductive languages consider bottom-up evaluation as operational mechanism, here we will focus on the development of an operational semantics based on bottom-up evaluation for functional logic languages. As in the logic paradigm, the bottom-up evaluation will consist in a magic transformation for a given program-query into a magic program-query for which the bottom-up evaluation will simulate the top-down one of the original program.
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