[September 27, 2000] An XML language "Description Logic Markup Language (DLML)" is presented in the web site overview thus: "DLML is not a language but rather a system of DTDs that allows to encode many (if not all) description logics in the same framework. So far, it is restricted to TBox encoding. One important motivation to build DTDs for description languages is to be able to embed formal knowledge (in DL) in documents; see the pages of the ESCRIRE action for more information. Another motivation is to experiment with simple representation language transformations for which description logics are well-suited. The DLML structures can be used for storing and communicating terminologies to other systems. But they can also be transformed in the process. [See the XML document manipulations presented on the web site which are achieved easily with XML Stylesheet Language Tranformations (XSLT); 'moreover the transformations are described in a modular way which follows the modular description of the logics themselves.'] . . . The goal of DLML is to encode description logics expressions into XML. For instance, the sentence 'All CSmaster students are bachelor students whose advisor is computer scientist' is phrased in description logics by the expression: CSMasterStudents < (and Bachelor Student (all advisor ComputerScientist)). In this example, CSMasterStudent, Bachelor and Student are called concepts and advisor is called a role. The sentence above is a concept introduction for the concept CSMasterStudents. It is primitive because introduced by the < symbol. This means that if all the CSmaster students are bachelor students whose advisor is computer scientist, the reverse is not supposed to hold. The symbols and and all are called (concept) constructors and used for building complex concept descriptions. The DLML takes advantage of the modularity of description logics in which each operator and introducer can be described independently and a logic assemble these operators. The resources available here are: (1) The encoding of many operators, (2) The definition of logics, and (3) The illustration of many transformations, including some taking advantage of the semantics of the logic. Some current development work: (1) The full semantics description of the logics provided by DLML (this can be used, for instance, in order to check that a particular transformation is valid). (2) A stylesheet for transfoming a logic specification (by providuing its constructors and introducers) into complete DTD and DSD for that logic..." See the project web site for examples and other references.
"The main effort of the research in knowledge representation is providing theories and systems for expressing structured knowledge and for accessing and reasoning with it in a principled way. Description Logics are considered the most important knowledge representation formalism unifying and giving a logical basis to the well known traditions of Frame-based systems, Semantic Networks and KL-ONE-like languages, Object-Oriented representations, Semantic data models, and Type systems." [From dl.kr.org]
References:
[November 29, 2001] "Preserving Modularity in XML Encoding of Description Logics." By Jérôme Euzenat (INRIA Rhône-Alpes, Montbonnot, France). Working notes. 10 pages, with 11 references. Presented at the 2001 International Description Logics Workshop (DL-2001). Stanford, USA, August 1-3, 2001. Published in the Workshop Proceedings. "Description logics have been designed and studied in a modular way. This has allowed a methodic approach to complexity evaluation. We present a way to preserve this modularity in encoding description logics in XML and show how it can be used for building modular transformations and assembling them easily. We show how the modularity of description logics, that has mainly be used at a theoretical level, can be turned into an engineering advantage in the context of the semantic web. For that purpose, we introduce a description logic markup language (DLML) which encodes description logics in XML and preserves their modularity. We then present transformations that are described on individual constructors and can be composed to form more complex transformations. By factoring out syntactic rules and processing methods, the same set of transformations can apply to many logics. Section 2 presents the syntactic encoding of description logics in XML. The third section illustrates the use of transformation of the XML form in order to achieve relatively complex transformations... The DLML framework offers a general encoding of description logics in XML such that the modularity of description logics can be used in XML (for extending the language, building transformation stylesheets). Although it has been illustrated only by restricted examples, such an encoding has great potential for the interoperability of knowledge representation systems. In particular, it allows the implementation of the 'family of languages' approach to semantic interoperability which takes advantage of a group of comparable languages (here description logics) in order to select the best suited for a particular task. We are currently experimenting the proof-carrying transformation idea in this context..." [source, Postscript]
See also Embedded Structured Content Representation In REpositories. "The main goal of ESCRIRE thus consists of comparing three types of knowledge representation formalisms (conceptual graphs, object-based knowledge representations and description logics) from the standpoint of the representation and the handling of document content. That will enable to highlight the desired properties and to evaluate qualitatively and quantitatively the performances of the implementation formalisms. Beyond the better knowledge of the techniques implied by the various projects, this work will advance the state of the art. A set of documents and a set of queries have been selected in a coordinated way. The efficiency of the respective formalisms will be assessed with regard to these queries. Each team specifies the integration of the formalism in XML and develops a query evaluation strategy depending on the considered formalism. The formalisms together with full-text search will be evaluated along a predefined protocol for assessing qualitative criteria (e.g., query expressivity, legibility) and quantitative ones (eg precision, recall). This evaluation will provide a precise analysis of the strengths and weaknesses of each knowledge representation formalism of content representation..." ESCRIRE publications include (1) "XML : un formalisme de représentation intermédiaire entre données semi-structurées et représentation par objets" and (2) "XML est-il le langage de représentation de connaissance de l'an 2000?".
Description Logics Web site - Maintained by Carsten Lutz.
DL workshops "There have been a series of 13 international Description Logics Workshops. The last one was the 2000 International Description Logics Workshop (DL2000) held in Aachen, Germany August 17 to August 19, 2000."
"Representing and reasoning on XML documents: A description logic approach." By Diego Calvanese, Giuseppe De Giacomo, and Maurizio Lenzerini. In Journal of Logic and Computation Volume 9, Number 3 (Oxford University Press, 1999), pages 295-318 (with 43 references). "Recent proposals to improve the quality of interaction with the World Wide Web suggest considering the Web as a huge semistructured database, so that retrieving information can be supported by the task of database querying. Under this view, it is important to represent the form of both the network, and the documents placed in the nodes of the network. However, the current proposals do not pay sufficient attention to represent document structures and reasoning about them. In this paper, we address these problems by providing a framework where Document Type Definitions (DTDs) expressed in the eXtensible Markup Language (XML) are formalized in an expressive Description Logic equipped with sound and complete inference algorithms. We provide methods for verifying conformance of a document to a DTD in polynomial time, and structural equivalence of DTDs in worst case deterministic exponential time, improving known algorithms for this problem which were double exponential. We also deal with parametric versions of conformance and structural equivalence, and investigate other forms of reasoning on DTDs. Finally, we show how to take advantage of the reasoning capabilities of our formalism in order to perform several optimization steps in answering queries posed to a document base." See the related publications by Giuseppe De Giacomo. [cache]
