In this paper, we present a data and an execution model that allow for efficient storage and retrieval of XML documents in a relational database. The data model is strictly based on the notion of binary associations: by decomposing XML documents into small, flexible and semantically homogeneous units we are able to exploit the performance potential of vertical fragmentation. Moreover, our approach provides clear and intuitive semantics, which facilitates the definition of a declarative query algebra. Our experimental results with large collections of XML documents demonstrate the effectiveness of the techniques proposed.

Due to the ubiquity and popularity of XML, users often

ISO Technical Committee 37, Terminology and other language and content resources, established an ISO 12620:2009 based Data Category Registry (DCR), called ISOcat (see http://www.isocat.org), to foster semantic interoperability of linguistic resources. However, this goal can only be met if the data categories are reused by a wide variety of linguistic resource types. A resource indicates its usage of data categories by linking to them. The small DC Reference XML vocabulary is used to embed links to data categories in XML documents. The link is established by an URI, which servers as the Persistent IDentifier (PID) of a data category. This paper discusses the efforts to mimic the same approach for RDF-based resources. It also introduces the RDF quad store based Relation Registry RELcat, which enables ontological relationships between data categories not supported by ISOcat and thus adds an extra level of linguistic knowledge.

The Max Planck Institute for Psycholinguistics in Nijmegen, The Netherlands, is creating a state-of-the-art web environment for the ISO TC 37 (terminology and other language and content resources) metadata registry. This Data Category Registry (DCR) is called ISOcat and encompasses data categories for a broad range of language resources. Under the governance of the DCR Board, ISOcat provides an open work space for creating data category specifications, defining Data Category Selections (DCSs) (domain-specific groups of data categories), and standardising selected data categories and DCSs. Designers visualise future interactivity among the DCR, reference registries and ontological knowledge spaces.

In this article we argue that the automatic generation of dynamic multimedia presentation requires both low-level collections of objective measurements for media units representing prototypical style elements, and high-level conceptual descriptions supporting contextual and presentational requirements. Only the combination of both facilitates the retrieval of adequate material and its user-centred presentation. We discuss the problems of visual signification for images in dynamic systems and explain how a combined approach can help overcome such problems. We then propose an architecture for such a system and present its applicability for a museum-oriented multimedia system with a working example. KeywordsMultimedia semantics, feature grammars, style-based multimedia presentation generation, multimedia retrieval INTRODUCTIONOver the last decade, museums have been contributing to the information revolution by digitising their collections and providing access to them for the general public. Currently, many sophisticated and visually pleasing environments, such as exhibitions in virtual galleries, art collections and presentations of different cultural artefacts, are available. A problem with these environments is that they are handcrafted. In nearly all cases, they lack adaptive [8] or adaptable qualities [28], which could otherwise facilitate the adjustment of the multimedia presentation to the specific context of an individual user. For overcoming these problems, various attempts to explore and develop innovative presentation techniques are described by [1,2,6,20,36]. These approaches facilitate the synthesis of multimedia documents and plan how this material is presented to various users. The underlying assumption of these systems, however, is that all material and its combinatorial possibilities are known.In dynamic environments, such as web-based museums, where neither the individual user requirements nor the requested material can be predicted in advance a top-down planning approach is not sufficient. Instead, we claim that a system must be provided with knowledge of simple codes, i.e. collections of objective measurements for media units [10,19] representing prototypical style elements, which are combined with high-level conceptual descriptions [31] supporting contextual and presentational requirements. Using such a combinatorial approach it is possible to establish conceptual presentations that support a better understanding of art, so that the system can find satisfactory solutions for upcoming questions (e.g. based on the content of an image), misunderstandings (rearrangement of the material) or non-understanding (creation of a new sequence).The mapping of high-level conceptual structures with low-level feature descriptions as an essential mechanism to enhance the automatic generation of dynamic style-oriented multimedia environments is part of the methodology followed in the Cuypers project [34]. The aim of this work is to improve existing search techniques on category and image features to facil...