Existing schema languages can lead to overdesign. They offer more choices than are necessary for purely descriptive (as contrasted with prescriptive) situations. A potential solution is to design based on “patterns” from real DTDs. Using three example situations, alternatives, repeatable homogeneous elements, and mixed content models, we derived a group of patterns sufficient to express all required structures in a descriptive environment. To provide a meaningful example, we propose a new instance-based schema language, DTD--, that derives schemas from tagged sample instances according to the patterns. Since there are few patterns, every document can be represented by a simple grammar where grammar rules can be directly inferred from the document, without any ambiguity. Design patterns for descriptive document substructures Table of
When reporting bugs in XML processing software, it is essential to be able to submit the actual documents that demonstrate the bugs. When reporting performance problems, it's even more important. However, many XML documents contain sensitive data that cannot be shared. This paper discusses a SAX-based technique for obscuring XML documents that removes most information content while retaining the complete structure of the original document. Obscuring XML Table of
The Text Encoding Initiative’s typed segment-boundary delimiter method is only one of several proposed mechanisms for handling overlap in TEI documents. HORSE (aka CLIX) defines a method by which an XML element is used normally when possible and as an improved version of the typed segment-boundary delimiter method when an overlap problem is encountered. A significant portion of the rules necessary for validation of HORSE markup can be expressed using Schematron. This, combined with an utter hack that can “HORSEify” the declaration of elements in a TEI Relax NG grammar, can provide a potential significant step forward in handling overlap in TEI documents. TEI HORSEing Around Table of
A type hierarchy enables extension of general types by specialized types for more precise semantics, thus allowing for flexibility of design and processing. A formal type hierarchy for discourse can realize benefits similar to those already seen for type hierarchies in OO design and ontologies. Because schema languages declare elements and content models, discourse types may be defined by specifying relationships between more specific (often pragmatic) models and more general models. Because refinement of discourse models may entail changes in containment structure, the type relationships must declare a mapping between containment structures. A Design Annotation Specialization Language can be used to declare type relationships and can be embedded as annotation elements within XML Schema or RelaxNG files or maintained externally as an annotation file for DTDs. Using the declared type hierarchy, an instance of a discourse model can be processed against base types to inherit formatting or behaviors and can be generalized to base types for interoperability. The author is proposing these strategies to the OASIS DITA Technical Committee as a possible direction for a future release of DITA. A unified type hierarchy for discourse A potential direction for DITA 2 Table of
Current XML differencing applications usually try to find a minimal sequence of edit operations that transform one XML document to another XML document (the so-called "edit script"). In our conviction, this approach often produces increments that are unintuitive for human readers and do not reflect the actual changes. We therefore propose in this article a different approach trying to maximize the retained structure instead of minimizing the edit sequence. Structure is thereby not limited to the usual tree structure of XML any kind of structural relations can be considered (like parent-child, ancestordescendant, sibling, document order). In our opinion, this approach is very flexible and able to adapt to the user's requirements. It produces more readable results while still retaining a reasonably small edit sequence. Structure-Preserving Difference Search for XML Documents Table of
The SGML feature CONCUR allowed for a document to be simultaneously marked up in multiple conflicting hierarchical tagsets but validated and interpreted in one tagset at a time. Alas, CONCUR was rarely implemented, and XML does not address the problem of conflicting hierarchies at all. The MuLaX document syntax is a non-XML syntax that enables multiply-encoded hierarchies by distinguishing different “layers” in the hierarchy by adding a layer ID as a prefix to the element names. The IDs tie all the elements in a single hierarchy together in an “annotation layer”. Extraction of a single annotation layer results in a well-formed XML document, and each annotation layer may be associated with an XML schema. The MuLaX processing model works on the nodes of one annotation layer at a time through Xpath-like navigation. CONCUR lives!
This paper describes the design of an XML language to formally specify constraints over Topic Maps (XTche). This language allows to express contextual conditions on classes of Topic Maps that are further processed by a XSLT based processor. With XTche, a topic map designer defines a set of restrictions that guarantee that a particular topic map is semantically valid. Topic Maps tend to grow quite fast. Most times the designer has some restrictions in mind like: what kind of topics should be used for abstract concepts, what topics may link to resources and what topics can not, ... All these restrictions tend to blur when things get big or if the some member of the team changes. In these situatiations an automatic system able to validate the restrictions is desirable. The constraining process presented in this paper is composed of a language and a processor. The language is based on XML Schema syntax (we have used the same syntax and concepts in a similar approach to RDFS). The processor is developed in XSLT language. XTche processor is very similar to the Schematron or XCSL processors: it's an high-level stylesheet that takes a XTche specification as input and generates a specific XSLT stylesheet. This stylesheet when applied to the Topic Map validates the constraints in the XTche specification. In this paper we will show, in abstract terms and with concrete examples, how to specify Topic Maps schemas and constraints with XTche.
This paper describes a formal model for topic maps called Q, and structurally similar representations of topic maps and RDF in this formal model.
The Web has amply demonstrated the benefits of an infrastructure that makes publishing and reference of semi-structured information easily accessible, but in many cases reference and reuse of such information is only at the level of complete files. The potential for greater benefits that may derive from sub-document structure and reference is currently being explored, but this exploration is limited by the fact that such references can only be used with a portion of the Web's content (i.e. that encoded in XML). We have developed a system, the Network-Oriented Document Abstraction Language (NODAL), that is designed to provide a common data model, schema language and sub-document reference system for web-accessible documents or databases encoded in any format (e.g. images, PDF or Word documents etc.). This system thus provides a common reference and access environment for all structured, semi-structured and unstructured data. In this paper, we describe the data model, schema language and URI-based reference language for NODAL and compare it with XML and other systems. Finally, we outline a number of ways that this system can be extended to allow for composition, synchronization and reuse of documents and databases and can thus form a hypertextual foundation for interactive application development without inhibiting interoperability with existing systems. In essence, with NODAL we can bring the benefits of markup and hypertext to all data formats.
This presentation is a contribution to the discussion about the future of semantic technologies, and more specifically the discussion about the proposed Topic Maps Reference Model. In this paper I will attempt to show that the terms which are used to describe the work being done in the semantic technologies are somewhat misleading, and I will propose using the term "perspective" instead of the term "ontology" to emphasize the fact that the vision of semantically integrated information depends on the point of view adopted. In this paper I will show that the traditional approach (top-down) which looks like the natural and reasonable thing to do when dealing with information models doesn't work efficiently as long as what we are interested in is connecting information from various and heterogenous sources. A Matter of Perspectives Talking About Talking About Topic Maps Table of
The success of XML has come with the explosion of the number of vocabularies defined to represent similar information. In many domains, ranging from life sciences to e- commerce, many mappings have been defined between these vocabularies as a strategy for information integration. However, as the vocabularies evolve, maintaining these complex mappings and all artifacts that rely on them remains one of the major issues in information integration. A critical aspect of schema (or vocabulary) evolution is the ability to perform an impact analysis across all artifacts that directly or indirectly depend on the changing vocabularies. When an evolving vocabulary is not directly used, but rather mapped to another one through a complex mapping expressed in languages such as XSLT or XQuery, an impact analysis can be performed at a fine level of granularity only if the dependencies between the source and the target vocabulary are also known with the same level of granularity. In this paper, we present an architecture for the static analysis of both XSLT and XQuery and a conservative and sound constraint-based analysis of these two languages that effectively uncovers input/output dependency information necessary for a fine grain impact analysis. For each element or attribute declaration d in the output schema the analysis determines all the attribute or element declarations in the input schemas whose instances may influence the evaluation of an instance of d. We show results of early experimental evaluation illustrating the accuracy and scalability of the approach.
Both ISO's Topic Map Standards and the W3C's Semantic Web Recommendations provide the means to construct meta-level semantic maps describing relationships between information resources. Developed independently, attempts at interoperability between the original Topic Map standard and RDF have proved challenging. However, ISO 13250's drafting of an explicit Topic Map Data Model (TMDM) early in 2005, combined with the advent of the W3C's more expressive Web Ontology Language (OWL) Recommendations in 2004, together now provide the possibility for authoring TMDMconforming Topic Maps directly in OWL. OWL provides the ability to express the TMDM constraints explicitly and to ensure that Topic Maps authored in OWL conform to the TMDM. This paper presents a construction of the TMDM model as an OWL-DL ontology. This “TMDM Ontology” is a construction in OWL of the Topic Map concepts modelled by the TMDM, making them available for use by Topic Map authors as a basis for building TMDM-compliant Topic Maps directly in OWL. Using OWL-DL as the language for Topic Map authoring gives users access to OWL's formal semantics, constraint expressivity, and suite of tools such as Protege, which includes an API and capability for ontology visualisation, querying, and automated constraint checking and reasoning using Description Logic reasoners. The approach described does not require the use of any Topic Map language, or Topic Map Constraint or Query language, although a simple algorithm could translate the OWL-authored Topic Maps directly into other TMDM-based Topic Map authoring languages if required, providing access to Topic Map engines and tools. Illustrating by example, a Topic Map written in OWL-DL using Protege is shown, highlighting the constraint and querying abilities provided, which overlap many of the requirements set by the ISO for a Topic Map Constraint Language and Query Language. One outstanding issue regarding the interpretation of Typing is identified, and options for its resolution are discussed. Building Topic Maps in OWL-DL
