State-of-the-art on evolution and reactivity

This report starts by, in Chapter 1, outlining aspects of querying and updating resources on the Web and on the Semantic Web, including the development of query and update languages to be carried out within the Rewerse project. From this outline, it becomes clear that several existing research areas and topics are of interest for this work in Rewerse. In the remainder of this report we further present state of the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs; in Chapter 4 event-condition-action rules, both in the context of active database systems and in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks

Web and Semantic Web Query Languages

A number of techniques have been developed to facilitate powerful data retrieval on the Web and Semantic Web. Three categories of Web query languages can be distinguished, according to the format of the data they can retrieve: XML, RDF and Topic Maps. This article introduces the spectrum of languages falling into these categories and summarises their salient aspects. The languages are introduced using common sample data and query types. Key aspects of the query languages considered are stressed in a conclusion

Towards MKM in the Large: Modular Representation and Scalable Software Architecture

MKM has been defined as the quest for technologies to manage mathematical knowledge. MKM "in the small" is well-studied, so the real problem is to scale up to large, highly interconnected corpora: "MKM in the large". We contend that advances in two areas are needed to reach this goal. We need representation languages that support incremental processing of all primitive MKM operations, and we need software architectures and implementations that implement these operations scalably on large knowledge bases. We present instances of both in this paper: the MMT framework for modular theory-graphs that integrates meta-logical foundations, which forms the base of the next OMDoc version; and TNTBase, a versioned storage system for XML-based document formats. TNTBase becomes an MMT database by instantiating it with special MKM operations for MMT.Comment: To appear in The 9th International Conference on Mathematical Knowledge Management: MKM 201

State-of-the-art on evolution and reactivity

This report starts by, in Chapter 1, outlining aspects of querying and updating resources on the Web and on the Semantic Web, including the development of query and update languages to be carried out within the Rewerse project. From this outline, it becomes clear that several existing research areas and topics are of interest for this work in Rewerse. In the remainder of this report we further present state of the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs; in Chapter 4 event-condition-action rules, both in the context of active database systems and in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks

Survey over Existing Query and Transformation Languages

A widely acknowledged obstacle for realizing the vision of the Semantic Web is the inability of many current Semantic Web approaches to cope with data available in such diverging representation formalisms as XML, RDF, or Topic Maps. A common query language is the first step to allow transparent access to data in any of these formats. To further the understanding of the requirements and approaches proposed for query languages in the conventional as well as the Semantic Web, this report surveys a large number of query languages for accessing XML, RDF, or Topic Maps. This is the first systematic survey to consider query languages from all these areas. From the detailed survey of these query languages, a common classification scheme is derived that is useful for understanding and differentiating languages within and among all three areas

Extensible metadata repository for information systems

Thesis submitted to Faculdade de Ciências e Tecnologia of the Universidade Nova de Lisboa, in partial fulfillment of the requirements for the degree of Master in Computer ScienceInformation Systems are, usually, systems that have a strong integration component and some of those systems rely on integration solutions that are based on metadata (data that describes data). In that situation, there’s a need to deal with metadata as if it were “normal”information. For that matter, the existence of a metadata repository that deals with the integrity, storage, validity and eases the processes of information integration in the information system is a wise choice. There are several metadata repositories available in the market, but none of them is prepared to deal with the needs of information systems or is generic enough to deal with the multitude of situations/domains of information and with the necessary integration features. In the SESS project (an European Space Agency project), a generic metadata repository was developed, based on XML technologies. This repository provided the tools for information integration, validity, storage, share, import, as well as system and data integration, but it required the use of fix syntactic rules that were stored in the content of the XML files. This situation causes severe problems when trying to import documents from external data sources (sources unaware of these syntactic rules). In this thesis a metadata repository that provided the same mechanisms of storage, integrity, validity, etc, but is specially focused on easy integration of metadata from any type of external source (in XML format) and provides an environment that simplifies the reuse of already existing types of metadata to build new types of metadata, all this without having to modify the documents it stores was developed. The repository stores XML documents (known as Instances), which are instances of a Concept, that Concept defines a XML structure that validates its Instances. To deal with reuse, a special unit named Fragment, which allows defining a XML structure (which can be created by composing other Fragments) that can be reused by Concepts when defining their own structure. Elements of the repository (Instances,Concepts and Fragment) have an identifier based on (and compatible with) URIs, named Metadata Repository Identifier (MRI). Those identifiers, as well as management information(including relations) are managed by the repository, without the need to use fix syntactic rules, easing integration. A set of tests using documents from the SESS project and from software-house ITDS was used to successfully validate the repository against the thesis objectives of easy integration and promotion of reuse

Storage, Querying and Inferencing for Semantic Web Languages

Harmelen, F.A.H. van [Promotor