The vision of the Semantic Web can only be realized through proliferation of well-known ontologies describing different domains. To enable interoperability in the Semantic Web, it will be necessary to break these ontologies down into smaller, well-focused units that may be reused. Currently, three problems arise in that scenario. Firstly, it is difficult to locate ontologies to be reused, thus leading to many ontologies modeling the same thing. Secondly, current tools do not provide means for reusing existing ontologies in new ontologies. Finally, ontologies are rarely static, but are being adapted to changing requirements. Hence, an infrastructure for management of ontology changes, taking into account dependencies between ontologies is needed. In this paper we present such an infrastructure addressing the aforementioned problems.

the web from a static collection of information into a distributed device of computation on the basis of Semantic Web technology making content within the World Wide Web machine-processable and machine-interpretable. Semantic Web Enabled Web Services will allow the automatic discovery, selection and execution of inter-organization business logic making areas like dynamic supply chain composition a reality. In this paper we introduce the vision of Semantic Web Enabled Web Services, describe requirements for building semantics-driven web services and sketch a first draft of a conceptual architecture for implementing semantic web enabled web services.

Abstract. Time modeling is a crucial feature in many application domains. However, temporal information often is not crisp, but is uncertain, subjective and vague. This is particularly true when representing historical information, as historical accounts are inherently imprecise. Similarly, we conjecture that in the Semantic Web representing uncertain temporal information will be a common requirement. Hence, existing approaches for temporal modeling based on crisp representation of time cannot be applied to these advanced modeling tasks. To overcome these difficulties, in this paper we present fuzzy interval-based temporal model capable of representing imprecise temporal knowledge. Our approach naturally subsumes existing crisp temporal models, i.e. crisp temporal relationships are intuitively represented in our system. Apart from presenting the fuzzy temporal model, we discuss how this model is integrated with the ontology model to allow annotating ontology definitions with time specifications. 1

Abstract. In this paper, we present h-match, an algorithm for dynamically matching distributed ontologies. By exploiting ontology knowledge descriptions, h-match can be used to dynamically perform ontology matching at different levels of depth, with different degrees of flexibility and accuracy. h-match has been developed in the Helios framework, conceived for supporting knowledge sharing and ontology-addressable content retrieval in peer-based systems. 1

Abstract. The huge number of available documents on the Web makes finding relevant ones a challenging task. The quality of results that traditional full-text search engines provide is still not optimal for many concepts, semantic relations and temporal issues are handled inadequately by full-text search. Ontologies and semantic metadata can provide a solution for these problems. This work examines how ontologies can be optimally exploited during the information retrieval process, and proposes a general framework which is based on ontology-supported semantic metadata generation and ontology-based query expansion. The framework can handle imperfect ontologies and metadata by combining results of simple heuristics, instead of relying on a “perfect ” ontology. This allows integrating results from traditional full-text engines, and thus supports a gradual transition from classical full-text search engines to ontology-based ones. 1

This paper presents a novel approach for context driven knowledge retrieval. The main focus is placed on the user interface to support the representation and contextualization of search results in a thematic category network, which can be present in the form of web directories like the Google category system or organizational ontologies. An interactive matrix display is used for showing relations between concepts and concept hierarchies of the directory, which are displayed along the two axes of a matrix. The interface allows pure browsing of the thematic structure as well as querying the underlying search engine and exploring the hits on a thematic level. The results of a search are not only shown as the commonly used, but effective plain text lists, but are classified in the category system. In this way, the tasks of browsing the categories and searching the information space are combined in one interface

Abstract. Web services aim at providing an interoperable framework for cross system and multiple domain communication. Current basic standards are allowing for first cases of practical use and evaluation. Since, however, the modeling of the underlying application domains is largely an open issue, web service support for cross domain applications is rather limited. This limitation is particularly severe in the area of enterprise services which could benefit substantially from well-defined semantics of multiple domains. This paper focuses on the representation of user-specific domain models and on the support of their coherent interpretation on both client and server side. Our approach is founded on the paradigm of Conceptual Content Management (CCM) and provides support for coherent model interpretation by automatically generating CCM system implementations from high-level domain model specifications. Our approach to CCM has been successfully applied in several application projects. 1

Much of the Semantic Web content is generated from databases, especially the instance data based on the ontology classes used in applications. A recurring problem is that the instance data does not always semantically conform to the ontology used. It may be ambiguous, incomplete, or partly erroneous. Validating the data is necessary when it is transformed to a more semantic format. This may be a difficult and laborious task given the large and complex ontologies and databases in use. This paper discusses the problem of validating existing database instance data according to an ontology. We show how Semantic Web standards can augment the syntactic data validation schemes of relational databases and XML towards semantic validation. A metadata editor for semantic validation is being implemented. Its idea is to provide an XML-based view to a relational database and transform the data into RDF instances conforming to an RDF Schema, the ontology. The tool will be applied in tranforming museum collection data into a semantically interoperable form in the Finnish Museums on the Semantic Web project.

Abstract. Although the first digital archives storing a huge number of resources came into existence years ago, they still lack effective retrieval methods. The most obvious example is the World Wide Web: search engines are improved constantly, however, their hits are still unsatisfactory apart from simplest queries. Most prosperous solutions employ user contexts to estimate the user’s information demand and use this information to deliver more adequate results. In the current paper we introduce the idea of resource context-based information retrieval. In this approach, semantic context description is assigned to each digital resource known to the system and this semantic metadata are exploited by each step during an intelligent search process. Our solution is implemented and evaluated in the VICODI project, as part of a web portal for European history. 1

Deliverable D12.1.1. (WP12.1) This document accompanies the SEKT web site and mailing lists. Important features of the web site, which consists of a public and a private part, as well as open issues are being described. A brief overview summarizes the existing mailing lists available for SEKT and some subscription details are presented. Both, web site and mailing lists, are up-and-running from the beginning of the project and are subject to continuous improvement.