Semantic Depth and arku up ~omp~exi ty*

In order to achieve interoperabiliiy among heterogeneous systems, markup languages such as XML and DAML are being used to describe distributed systems and data. The abiliiy lo successfully interoperate based on semantic markup depend on the abiliiy to create, use and manage shared onfologies of concepts and !heir interrelationships. Specifically, communicating systems in a nehvorked environment have to achieve a certain level of semanfic agreement for them to understand and process exchanged data. A challenging question is how deep the semantic agreement has to be in order to satisjj !he communication needs in an environment. Additionally, whaf is the markup complexity resulting from pursuing that depth of semanfic agreement? This paper introduces the concept of semantic depfh and markup complexity and proposes models fo measure the markup complexity. Furthermore, it is shown that markup complexity can be reduced by employing hierarchical ontologies after partitioning the domain into smaller sub-domains.