Exploiting the full potential of the World Wide Web will require semantic as well as syntactic interoperability. This can best be achieved by providing a further representation and inference layer that builds on existing and proposed web standards. The OIL language extends the RDF schema standard to provide just such a layer. It combines the most attractive features of frame based languages with the expressive power, formal rigour and reasoning services of a very expressive description logic. 1

Currently computers are changing from single isolated devices to entry points into a worldwide network of information exchange and business transactions. Therefore, support in the exchange of data, information, and knowledge is becoming the key issue in computer technology today. Ontologies provide a shared and common understanding of a domain that can be communicated between people and across application systems. Ontologies will play a major role in supporting information exchange processes in various areas. A prerequisite for such a role is the development of a joint standard for specifying and exchanging ontologies. This paper deals with precisely this necessity. We will present OIL which is a proposal for such a standard. It is based on existing proposals such as OKBC, XOL and RDF, and enriches them with necessary features for expressing rich ontologies. The paper presents the motivation, underlying rationale, modeling primitives, syntax, semantics, and tool environment of OIL. With OIL, we want to make a proposal that initiates a discussion leading to a useful and well defined consensus amongst a large community which could use such an approach.

Ontologies play a key role in the advent of the Semantic Web. An important problem when dealing with ontologies is the modification of an existing ontology in response to a certain need for change. This problem is a complex and multifaceted one, because it can take several different forms and includes several related subproblems, like heterogeneity resolution or keeping track of ontology versions. As a result, it is being addressed by several different, but closely related and often overlapping research disciplines. Unfortunately, the boundaries of each such discipline are not clear, as the same term is often used with different meanings in the relevant literature, creating a certain amount of confusion. The purpose of this paper is to identify the exact relationships between these research areas and to determine the boundaries of each field, by performing a broad review of the relevant literature.

this report is to bring together two current research activities, carried out at the Vrije Universiteit Amsterdam and at the Center for Computing Technologies at the University of Bremen. The context of the research at the Free University is the European project "On-To-Knowledge" #www.ontoknowledge.com# whose goal it is to provide support for e#cient and e#ective knowledge management. The scope of the project are weakly structured information sources in the internet. The approach of the project is to use ontologies to provide explicitly available semantic information about information sources in order to support the acquisition, maintenance and access to these information sources. Background of the research at the Center for Computing Technologies is the Project INTEREC-IIC Project "DataShare" #Voegele, 2000#. The goal of this project is to provide intelligent support for processes concerned with environmental protection. Scope of the work at the center for computing technologies is a common access to available information sources throughout the whole process. The main problem occurring in this context is the heterogeneity of the information needed in a process

It has been claimed that topic metadata can be used to improve the accuracy of text searches. Here, we test this claim by examining the contribution of metadata to effective searching within websites published by a university with a strong commitment to and substantial investment in metadata. We use four sets of queries, a total of 463, extracted from the university's official query logs and from the university's site map. The results are clear: the available metadata is of little value in ranking answers to those queries. A follow-up experiment with the websites published in a particular government jurisdiction queries confirms that this conclusion is not specific to the particular university. Examination of the metadata present at the university reveals that, in addition to implementation deficiencies, there are inherent problems in trying to use subject and description metadata to enhance the searchability of websites. Our experiment

Currently computers are changing from single isolated devices to entry points into a worldwide network of information exchange and business transactions. Therefore, support in the exchange of data, information, and knowledge is becoming the key issue in computer technology today. Ontologies provide a shared and common understanding of a domain that can be communicated between people and across application systems.

Abstract. Blogs have the a ordance to become an integral part of teaching and learning processes as a vehicle for knowledge management. Open, exible systems integrating blogs provide user-friendly, personalised microlearning environments while ensuring ubiquitous access. This paper concentrates on blog interoperability in an open space for learning and collaboration. As blogging is one of the most popular web-based forms of publishing today, there is a plethora of di erent blogging tools, feed readers, and aggregators, enabling information dissemination, ltering, and retrieval. Several di erent data structure and interaction standards emerged which make integration a real challenge. This paper aims at creating distributed microlearning environments basing on networks of integrated blogs, discusses problems of such an integration along with possible solutions, and proposes an architecture for loosely-coupled blog integration. The core of this infrastructure consists of a service interface for feed management that allows learners as well as facilitators to automatically set up channel structures for feed syndication, while e ectively reducing the management e orts thereof through proper system support. 1