XML is the W3C standard document format for writing and exchanging information on the Web. RDF is the W3C standard model for describing the semantics and reasoning about information on the Web. Unfortunately, RDF and XML---although very close to each other---are based on two different paradigms. We argue that in order to lead the Semantic Web to its full potential, the syntax and the semantics of information needs to work together. To this end, we develop a model theory for the XML XQuery 1.0 and XPath 2.0 Data Model, which provides a unified model for both XML and RDF. This unified model can serve as the basis for Web applications that deal with both data and semantics. We illustrate the use of this model on a concrete information integration scenario. Our approach enables each side of the fence to benefit from the other, notably, we show how the RDF world can take advantage of XML query languages, and how the XML world can take advantage of the reasoning capabilities available for RDF.

Abstract. Recently XML is the standard format used for the exchange of data between information systems and is also frequently applied as a logical database model. If we use XML as a logical database model we need a conceptual model for the description of its semantics. However, XML as a logical database model has some special characteristics which makes existing conceptual models as E-R or UML unsuitable. In this paper, the current approaches to the conceptual modeling of XML data are described in an uniform style. A list of requirements for XML conceptual models is presented and described approaches are compared on the base of the requirements.

Two algorithms, called NeT and CoT, to translate relational schemas to XML schemas using various semantic constraints are presented. The XML schema representation we use is a language-independent formalism named XSchema, that is both precise and concise. A given XSchema can be mapped to a schema in any of the existing XML schema language proposals. Our proposed algorithms have the following characteristics: (1) NeT derives a nested structure from a flat relational model by repeatedly applying the nest operator on each table so that the resulting XML schema becomes hierarchical, and (2) CoT considers not only the structure of relational schemas, but also semantic constraints such as inclusion dependencies during the translation. It takes as input a relational schema where multiple tables are interconnected through inclusion dependencies and converts it into a good XSchema. To validate our proposals, we present experimental results using both real schemas from the UCI repository and synthetic schemas from TPC-H.

Abstract. Due to the fast growth of internet based electronic business activities, languages for modeling as well as methods for analyzing and executing distributed business processes are becoming more and more important. Efficient inter-organizational business processes in the field of e-commerce require the integration of electronic document interchange and inter-organizational process management. We propose to support inter-organizational business processes by so-called XML nets, a new variant of high-level Petri nets. XML nets are a formal, graphical modeling language that allows to model both the flow of XML documents and the control flow of the underlying business process. XML nets are based on GXSL, a novel graphical XML schema definition language, and its related graphical XML document manipulation language XManiLa. They can be directly executed by a respective workflow engine. Advantage of the formal foundation of XML nets can be taken, e.g., when analyzing a (global) interorganizational workflow model. XML nets support the identification of relevant process fragments and their allocation to the appropriate organizational units. Thus XML nets help to derive an improved, process-oriented organizational structure. 1.

XML is the W3C standard document format for writing and exchanging information on the Web. RDF is the W3C standard model for describing the semantics and reasoning about information on the Web. Unfortunately, RDF and XML -- although very close to each other -- are based on two different paradigms. We argue that in order to lead the Semantic Web to its full potential, the syntax and the semantics of information need to work together. To this end, we develop a model theory for the XML XQuery 1.0 and XPath 2.0 Data Model, which provides a unified model for both XML and RDF. This unified model can serve as the basis for Web applications that deal with both data and semantics. We illustrate the use of this model on a concrete information integration scenario. Our approach enables each side of the fence to benefit from the other, notably, we show how the RDF world can take advantage of XML Schema description and XML query languages, and how the XML world can take advantage of the reasoning capabilities available for RDF. Our approach can also serve as a foundation for the next layer of the Semantic Web, the ontology layer, and we present a layering of an ontology language on top of our approach.

Information sources over the WWW contain a large amount of data organized according to different interests and values. Thus, it is important that facilities are there to enable users to extract information of interests in a simple and effective manner. To do this, information from the Web sources need to be extracted automatically according to users' interests. However, the extraction of information requires in-depth knowledge of relevant technologies and the extraction process is slow, tedious and difficult for ordinary users. We propose the Wiccap Data Model, an XML data model that maps Web information sources into commonly perceived logical models. Based on this data model, ordinary users are able to extract information easily and efficiently. To accelerate the creation of data models, we also define a formal process for creating such data model and have implemented a software tool to facilitate and automate the process of producing Wiccap Data Models.

Because of its success, XML is increasingly used in many different application areas, and is moving towards the center of applications, evolving from an exchange format to the native data format of application components. These developments suggest that similar to other core areas of application design, XML should be designed conceptually before the implementation tasks of designing markup and writing schemas are approached. In this paper, we describe why conceptual modeling will become an important part of the XML landscape, what issues need to be addressed, and what the requirements for a conceptual modeling language for XML are.

This dissertation addresses mainly three issues needed to support query relaxation for XML model: framework formalization, extension of existing database techniques, and data conversion between XML and relational models.

XML is rapidly becoming the standard for data representation, especially for data that is ex-changed on the web. XML Schema [XML01] is used to describe the structure and the content of XML data. Although XML Schema is useful for specifying and validating XML documents, systems analysts who store their models using XML need a simple conceptual model to help improve mod-

Current XML query languages operate on XML instances only but ignore valuable conceptual level information that is "buried" inside complex XML Schema documents. For example, XPath ...