331 research outputs found

    Ensuring Query Compatibility with Evolving XML Schemas

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    During the life cycle of an XML application, both schemas and queries may change from one version to another. Schema evolutions may affect query results and potentially the validity of produced data. Nowadays, a challenge is to assess and accommodate the impact of theses changes in rapidly evolving XML applications. This article proposes a logical framework and tool for verifying forward/backward compatibility issues involving schemas and queries. First, it allows analyzing relations between schemas. Second, it allows XML designers to identify queries that must be reformulated in order to produce the expected results across successive schema versions. Third, it allows examining more precisely the impact of schema changes over queries, therefore facilitating their reformulation

    Integrating data warehouses with web data : a survey

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    This paper surveys the most relevant research on combining Data Warehouse (DW) and Web data. It studies the XML technologies that are currently being used to integrate, store, query, and retrieve Web data and their application to DWs. The paper reviews different DW distributed architectures and the use of XML languages as an integration tool in these systems. It also introduces the problem of dealing with semistructured data in a DW. It studies Web data repositories, the design of multidimensional databases for XML data sources, and the XML extensions of OnLine Analytical Processing techniques. The paper addresses the application of information retrieval technology in a DW to exploit text-rich document collections. The authors hope that the paper will help to discover the main limitations and opportunities that offer the combination of the DW and the Web fields, as well as to identify open research line

    A Survey on Mapping Semi-Structured Data and Graph Data to Relational Data

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    The data produced by various services should be stored and managed in an appropriate format for gaining valuable knowledge conveniently. This leads to the emergence of various data models, including relational, semi-structured, and graph models, and so on. Considering the fact that the mature relational databases established on relational data models are still predominant in today's market, it has fueled interest in storing and processing semi-structured data and graph data in relational databases so that mature and powerful relational databases' capabilities can all be applied to these various data. In this survey, we review existing methods on mapping semi-structured data and graph data into relational tables, analyze their major features, and give a detailed classification of those methods. We also summarize the merits and demerits of each method, introduce open research challenges, and present future research directions. With this comprehensive investigation of existing methods and open problems, we hope this survey can motivate new mapping approaches through drawing lessons from eachmodel's mapping strategies, aswell as a newresearch topic - mapping multi-model data into relational tables.Peer reviewe

    Accelerating data retrieval steps in XML documents

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    Verifying Recursive Active Documents with Positive Data Tree Rewriting

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    This paper proposes a data tree-rewriting framework for modeling evolving documents. The framework is close to Guarded Active XML, a platform used for handling XML repositories evolving through web services. We focus on automatic verification of properties of evolving documents that can contain data from an infinite domain. We establish the boundaries of decidability, and show that verification of a {\em positive} fragment that can handle recursive service calls is decidable. We also consider bounded model-checking in our data tree-rewriting framework and show that it is \nexptime-complete

    A distance learning environment architecture

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    This paper presents the core architecture of NURAXI, a multimedia research platform aimed at the design, generation, deployment, management and use of intelligent distance learning environments. It describes the actors and services that are involved in the production and use of intelligent distance learning environments, the structures that are at the heart of the environment, and the processes that use these structures. The competence notion is the central component around which both author's and student's interactions gravitate. An author generates the training material on the basis of competencies to be acquired by a student, and the means to get them, i.e. the related activities and contents. A student accesses the pedagogical material by first selecting his/her learning objectives. The training path is made of dynamically created pedagogical activities. Examples of implemented activities are also shown in the paper. The platform presents a number of interesting features including re-usability of didactic components; adaptability of the training material to the student model; dynamic definition of the training path; modularity, and interoperability thanks to the adoption of standard and open solutions in terms of document structures, ontologies, design and implementation techniques. All these advantages derive from the integration of technologies such as the XML paradigm, Servlets, Software Agents, and Distributed Databases

    Impact Of XML On Data Interchange: An XML/EDI Model

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    Extensible mark-up language (XML) is emerging as the main standard of representation of structured documents on the World Wide Web (WWW) (Gibb, 2000).  An XML/EDI model is presented with advantages and challenges of this model.  XML is here to stay and with ever increasing number of big players adopting it, it will become a major component in application and systems design in the near future

    Redocumentation through design pattern recovery:: an investigation and an implementation

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    In this thesis, two methods are developed in an aid to help users capture valuable design information and knowledge and reuse them. They are the design pattern recovery (DPR) method and pattern-based redocumentation (PBR) method. The DPR method is for matching up metrics of patterns with patterns themselves in order to capture valuable design information. Patterns are used as a container for storing the information. Two new metrics, i.e., p-value and s-value are introduced. They are obtained by analysing product metrics statistically. Once patterns have been detected from a system, the system can be redocumented using these patterns. Some existing XML (extensible Markup Language) technologies are utilised in order to realise the PRB method. Next, a case study is carried out to validate the soundness and usefulness of the DPR method. Finally, some conclusions drawn from this research are summarised, and further work is suggested for the researchers in software engineering

    A simple and efficient step towards type-correct XSLT transformations

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    XSLT 1.0 is a standardized functional programming language and widely used for defining transformations on XML models and documents, in many areas of industry and publishing. The problem of XSLT type checking is to verify that a given transformation, when applied to an input which conforms to a given structure definition, e.g. an XML DTD, will always produce an output which adheres to a second structure definition. This problem is known to be undecidable for the full range of XSLT and document structure definition languages. Either one or both of them must be significantly restricted, or only approximations can be calculated. The algorithm presented here takes a different approach towards type correct XSLT transformations. It does not consider the type of the input document at all. Instead it parses the fragments of the result document contained verbatim in the transformation code and verifies that these can potentially appear in the result language, as defined by a given DTD. This is a kind of abstract interpretation, which can be executed on the fly and in linear time when parsing the XSLT program. Generated error messages are located accurately to a child subsequence of a single result element node. Apparently the method eliminates a considerable share of XSLT programming errors, on the same order of magnitude as a full fledged global control-flow analysis

    On Language Processors and Software Maintenance

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    This work investigates declarative transformation tools in the context of software maintenance. Besides maintenance of the language specification, evolution of a software language requires the adaptation of the software written in that language as well as the adaptation of the software that transforms software written in the evolving language. This co-evolution is studied to derive automatic adaptations of artefacts from adaptations of the language specification. Furthermore, AOP for Prolog is introduced to improve maintainability of language specifications and derived tools.Die Arbeit unterstützt deklarative Transformationswerkzeuge im Kontext der Softwarewartung. Neben der Wartung der Sprachbeschreibung erfordert die Evolution einer Sprache sowohl die Anpassung der Software, die in dieser Sprache geschrieben ist als auch die Anpassung der Software, die diese Software transformiert. Diese Koevolution wird untersucht, um automatische Anpassungen von Artefakten von Anpassungen der Sprachbeschreibungen abzuleiten. Weiterhin wird AOP für Prolog eingeführt, um die Wartbarkeit von Sprachbeschreibungen und den daraus abgeleiteten Werkzeugen zu erhöhen
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