. Motivated by applications that demand for the adequate representation of part-whole relations, different possibilities of representing transitive relations in terminological knowledge representation systems are investigated. A well-known concept language, ALC, is extended by three different kinds of transitive roles. It turns out that these extensions differ largely in expressiveness and computational complexity, hence this investigation gives insight into the diverse alternatives for the representation of transitive relations such as part-whole relations, family relations or partial orders in general. 1 Introduction Terminological knowledge representation systems (TKR-systems) are powerful means to represent the unambiguous, well-defined terminological knowledge in technical and other domains. Mainly, TKR-systems consist of two parts: A knowledge base, which contains the explicit concept definitions given in a so-called concept language, and an inference engine which is able to inf...

The aim of this project is to investigate what kind of terminological knowledge representation system (TKR-system) is able to support the modeling of huge chemical plants. In this highly complex modeling application, a TKR-system is the appropriate tool to serve as a user--database interface. What distinguishes TKR-systems from database systems is their ability to infer implicit knowledge from the knowledge explicitly stored in a knowledge base. TKR-systems differ among other aspects in the concept language that can be used for the representation of the application relevant knowledge. On the other hand, different kinds of knowledge from different applications ask for different concept languages. This process modeling application asks for the consideration of new concept languages and even for new constructors of these languages. To aggravate the situation, the amount of time and space needed by the reasoning services of a TKR-system increases with its expressive power. Hence the choi...

. Aggregated objects play an important role in many knowledge representation applications. For the adequate representation of aggregated objects, it is crucial to represent part-whole relations. We discuss properties of part-whole relations and extend the description logic ALC with means for the adequate representation of part-whole relations and thus of aggregated objects. 1 Motivation Description logics are a family of knowledge representation formalisms well-suited for the representation of and reasoning about configurations [27, 21], ontologies [19], and database schemata, where they can support schema design, evolution, and query optimisation [4, 7], source integration in heterogeneous databases/data warehouses [5, 6], and conceptual modeling of multidimensional aggregation [11]. In all these applications, aggregated objects play a central role, that is, objects that are composed of various parts, which again can be composite, etc. It is natural to describe an aggregated object...

In process engineering, as in many other application domains, the domain specific knowledge is far too complex to be described entirely using description logics. Hence this knowledge is often stored using an object-oriented system, which, because of its high expressiveness, provides only weak inference services. In particular, the process engineers at RWTH Aachen have developed a frame-like language for describing process models. In this paper, we investigate how the powerful inference services provided by a DL system can support the users of this frame-based system. In addition, we consider extensions of description languages that are necessary to represent the relevant process engineering knowledge. The application domain Process engineering is concerned with the design and operation of chemical processes that take place in large chemical plants. This engineering task includes activities like deciding on an appropriate flowsheet structure (e.g. configuration of reaction and separat...

We introduce a concept to model subtle part-whole-semantics for the use with interactive 3d-models of human anatomy. Similar to experiences with modeling partonomies for physical artifacts like machines or buildings we found one unique part-whole-relation to be insufficient to represent anatomical reality. This claim will be illustrated with anatomical examples. According to the requirements these examples demand, a semantic classification of part-wholerelations is introduced. Initial results in modeling anatomical partonomies for a 3d-visualization environment proved this approach to be an promising way to represent anatomy and to enable powerful complex inferences.