Evaluation von Wissensrepräsentationssystemen

Ziel dieses Berichtes ist eine Evaluation von aktuellen Wissensrepräsentationssystemen, insbesondere terminologischen Logiken. Nach Aufstellung der relevanten Evaluationskriterien erfolgt zunächst eine allgemeine Behandlung von KL-ONE - der Urmutter der terminologischen Logiken -, wobei schon einige inhärente kritische Punkte der zu behandelnden Systeme aufgezeigt werden. Anschließend werden Syntax- und Semantikdefinitionen von KL-ONE-Derivaten vorgestellt, um deren Sprachumfang zu vergleichen. Neben den gängigen KL-ONE-Derivaten wird auch die in LILOG verwendete Repräsentationssprache vorgestellt. Abschließend erfolgt ein zusammenfassender Vergleich der Systeme. Hierbei stellt sich heraus, dass insbesondere die Systeme LOOM, CLASSIC, KRIS und BACK bezüglich des verwendeten Sprachumfangs und der Effizienz der Inferenzen gut abschneiden. Die Systeme BACK und KRIS sind dabei für Verbmobil besonders relevant, da sie relativ leicht verfügbar sind. Außerdem zeichnet sich BACK durch ein gut strukturiertes Handbuch aus und eine schnelle neue Implementierung In C. Kritisch bei allen vorgestellten Systemen ist die Darstellung zeitlicher Zusammenhänge (Ereignisse, Aktionen); hierzu liegen jedoch schon Forschungsergebnisse für die Erweiterung der terminologischen Sprachen vor

ONTOGENERATION: Reusing Domain and Linguistic Ontologies for Spanish Text Generation

A significant problem facing the reuse of ontologies is to make their content more widely accessible to any potential user. Wording all the information represented in an ontology is the best way to ease the retrieval and understanding of its contents. This article proposes a general approach to reuse domain and linguistic ontologies with natural language generation technology, describing a practical system for the generation of Spanish texts in the domain of chemical substances. For this purpose the following steps have been taken: (a) an ontology in the chemicals domain developed under the METHONTOLOGY framework and the Ontology Design Environment (ODE) has been taken as knowledge source; (b) the linguistic ontology GUM (Generalized Upper Model) used in other languages has been extended and modified for Spanish; (c) a Spanish grammar has been built following the systemic-functional model by using the KPML (Komet-Penman Multilingual) environment. As result, the final system named Ontogeneration permits the user to consult and retrieve all the information of the ontology in Spanish

25 years development of knowledge graph theory: the results and the challenge

The project on knowledge graph theory was begun in 1982. At the initial stage, the goal was to use graphs to represent knowledge in the form of an expert system. By the end of the 80's expert systems in medical and social science were developed successfully using knowledge graph theory. In the following stage, the goal of the project was broadened to represent natural language by knowledge graphs. Since then, this theory can be considered as one of the methods to deal with natural language processing. At the present time knowledge graph representation has been proven to be a method that is language independent. The theory can be applied to represent almost any characteristic feature in various languages.\ud The objective of the paper is to summarize the results of 25 years of development of knowledge graph theory and to point out some challenges to be dealt with in the next stage of the development of the theory. The paper will give some highlight on the difference between this theory and other theories like that of conceptual graphs which has been developed and presented by Sowa in 1984 and other theories like that of formal concept analysis by Wille or semantic networks