An XQuery-based Model Transformation Language

In this paper we propose a framework for model transformation in XQuery. Our proposal aims to provide the elements for using XQuery as a transformation language. With this aim, our framework provides a mechanism for automatically obtaining an XQuery library for a given meta-model. Meta-models are defined as XML schemas, and the XQuery library serves to query and create elements of an XML Schema. Transformations abstract from XML representation, in the sense of, elements from meta-models are encapsulated by XQuery functions. We have also studied how to use our framework for model validation. Source and target models and transformations are validated by considering constraints. The framework has been tested with a case study of transformation in UML, where the XML-based representation of models is achieved by the standardized language XMI

Anatomy of an XML-based Text Corpus Server

Proceedings of the 16th Nordic Conference of Computational Linguistics NODALIDA-2007. Editors: Joakim Nivre, Heiki-Jaan Kaalep, Kadri Muischnek and Mare Koit. University of Tartu, Tartu, 2007. ISBN 978-9985-4-0513-0 (online) ISBN 978-9985-4-0514-7 (CD-ROM) pp. 337-344

FACHBEITRAG Unleashing XQuery for Data-Independent Programming

an SQL equivalent for XML data, but its roots in functional programming make it also a perfect choice for processing almost any kind of structured and semi-structured data. Apart from standard XML processing, however, advanced language features make it hard to efficiently implement the complete language for large data volumes. This work proposes a novel compilation strategy that provides both flexibility and efficiency to unleash XQuery’s potential as data programming language. It combines the simplicity and versatility of a storage-independent data abstraction with the scalability advantages of set-oriented processing. Expensive iterative sections in a query are unrolled to a pipeline of relational-style operators, which is open for optimized join processing, index use, and parallelization. The remaining aspects of the language are processed in a standard fashion, yet can be compiled anytime to more efficient native operations of the actual runtime environment. This hybrid compilation mechanism yields an efficient and highly flexible query engine that is able to drive any computation from simple XML transformation to complex data analysis, even on non-XML data. Experiments with our prototype and stateof-the-art competitors in classic XML query processing and business analytics over relational data attest the generality and efficiency of the design

Extending the learning object definition to represent programming problems

The present generation of eLearning platforms values the interchange of learning objects standards. Nevertheless, for specialized domains these standards are insufficient to fully describe all the assets, especially when they are used as input for other eLearning services. To address this issue we extended an existing learning objects standard to the particular requirements of a specialized domain, namely the automatic evaluation of programming problems. The focus of this paper is the definition of programming problems as learning objects. We introduce a new schema to represent metadata related to automatic evaluation that cannot be conveniently represented using existing standards, such as: the type of automatic evaluation; the requirements of the evaluation engine; or the roles of different assets - tests cases, program solutions, etc. This new schema is being used in an interoperable repository of learning objects, called crimsonHex.European Comissio

A schema-only approach to validate XML schema mappings

Since the emergence of the Web, the ability to map XML data between different data sources has become crucial. Defining a mapping is however not a fully automatic process. The designer needs to figure out whether the mapping is what was intended. Our approach to this validation consists of defining and checking certain desirable properties of mappings. We translate the XML schemas and the mapping into first-order logic formalism and apply a reasoning mechanism to check the desirable properties automatically, without assuming any particular instantiation of the schemas.Preprin

XGI: A Graphical Interface for XQuery Creation and XML Schema Visualization

XML (Extensible Markup Language) is used in many contexts of modern information technology to facilitate sharing of information between heterogeneous data sources and inter-platform applications. The prevalence of XML implementation in data storage and exchange necessitates a method to adequately query XML data. The World Wide Web Consortium (W3C) is proposing XQuery as the standard querying language for semistructured XML data. XQuery is designed for experienced database programmers, since its syntax and capabilities are analogous to the SQL relational query language. Therefore, the inherent complexity of formulating XQuery statements makes it an intimidating task for anyone, except an expert in the XQuery language, to construct queries. The development of XQuery Graphical Interface (XGI), a visual interface for creating XQuery in a graphical format, is motivated by the need to simplify the query formation for unskilled users and speed up the query construction for expert users. The implementation of XGI is mainly inspired by three existing systems: Query and Reporting Semistructured Data (QURSED), XQuery By Example (XQBE), and XBrain. A review of these systems and many other systems has helped us understand the benefits and drawbacks of various system design approaches, and has assisted us in identifying a set of features for XGI that will successfully reduce the complexity of creating queries in the XQuery language. XGI provides a web interface for users to explore their own XML source data schema, search for specific schema elements, and visually create queries in the XQuery language for the targeted XML data source. A validation of the XGI system has verified its ability to efficiently and accurately create queries for various XML data sources. From the validation, we have recognized some strengths and weaknesses of the XGI system compared to other systems. We also recommend several areas in which XGI can be improved

Generating SPARQL Executable Mappings to Integrate Ontologies

Data translation is an integration task that aims at populat- ing a target model with data of a source model by means of mappings. Generating them automatically is appealing insofar it may reduce inte- gration costs. Matching techniques automatically generate uninterpreted mappings, a.k.a. correspondences, that must be interpreted to perform the data translation task. Other techniques automatically generate ex- ecutable mappings, which encode an interpretation of these correspon- dences in a given query language. Unfortunately, current techniques to automatically generate executable mappings are based on instance ex- amples of the target model, which usually contains no data, or based on nested relational models, which cannot be straightforwardly applied to semantic-web ontologies. In this paper, we present a technique to auto- matically generate SPARQL executable mappings between OWL ontolo- gies. The original contributions of our technique are as follows: 1) it is not based on instance examples but on restrictions and correspondences, 2) we have devised an algorithm to make restrictions and correspondences explicit over a number of language-independent executable mappings, and 3) we have devised an algorithm to transform language-independent into SPARQL executable mappings. Finally, we evaluate our technique over ten scenarios and check that the interpretation of correspondences that it assumes is coherent with the expected results.Ministerio de Educación y Ciencia TIN2007-64119Junta de Andalucía P07-TIC-2602Junta de Andalucía P08-TIC-4100Ministerio de Ciencia e Innovación TIN2008-04718-EMinisterio de Ciencia e Innovación TIN2010-09809-EMinisterio de Ciencia e Innovación TIN2010-10811-EMinisterio de Ciencia e Innovación TIN2010-09988-