Projekt ACS

IBM - Autonomic Computing Study

The major objective of this document is to help bringing IBM’s On Demand Computing approach to its full potential by extending and combining it with a recent computer science trend "Semantic Web". Specifically, we will focus on how Semantic Web techniques may be integrated with Web Services, Grid computing and Autonomic Computing.
The term "Semantic Web" encompasses efforts to build an extended WWW architecture that enhances content with formal semantics on the basis of metadata. This will enable automated agents to reason about Web content, and carry out more intelligent tasks on behalf of the user. The Semantic Web is based on so-called ontologies. Ontologies are explicit conceptual and semantic data models. They are well-suited for describing heterogeneous, distributed and semistructured information sources that can be found on the Web. By defining shared and common vocabularies, ontologies help both people and machines to communicate concisely, supporting the exchange of semantics instead of syntax.
In this document we provide guidelines for using Semantic Web techniques in On Demand Computing. Furthermore, we show how Web Services, Grid Computing and Autonomic Computing can benefit from Semantic Web techniques. In specific, the advantages of semantics for Web Services are discussed in the section Semantic Web Services, whereas the section about Semantic Grid shows how semantics can improve Grid Computing systems. Finally, in the Autonomic Systems section, we demonstrate how Semantic Web techniques can be used as a basis for modelling and integrating components.
The core idea of Semantic Web Services is to combine Web services and Semantic Web technology. The benefits of this integration include increased visibility of Web services, because ontology-based approaches allow for semantically expressive advertising services on the Web. Therefore, it leads to better discovery of services. Further, the benefits include better usability because a more formal Web service description enables automatic composition of Web Services. Thus, we envisage a smooth evolution from Web services for human users such as targeted by current industry (quasi-)standards toward Web services for personalized machine agents that assist the user.
Furthermore, the Grid community is beginning to exploit technologies developed for Web Services and to realise the of Semantic Web technologies towards Semantic Grids. The technologies that are being developed for the Semantic Web will have important roles to play in grid services. Many decision making processes that go into assembling services into an application can be empowered by providing richer and deeper descriptions of service properties and their semantics. Ontologies will ultimately provide rich, seamless and pervasive access to globally distributed heterogeneous resources.
Next, the ever-increasing demand of data and resource sharing in the context of Autonomic Computing has to rely on a solid conceptual foundation in order to give a precise semantics to the data available in different components and eventually travelling over the networks. The actual demand is not for a unique conceptualisation, but for an unambiguous communication of complex and detailed concepts (possibly expressed in different languages), leaving each user free to make explicit his/her conceptualisation. Ontology seems to be the optimal candidate to face this problem. The second issue is data diversity – the heterogeneous structure of data sources. Heterogeneity occurs at all levels. Reconciling heterogeneous data has been achieved through ontologies. These two ways of using ontologies in autonomic systems are also discussed in this deliverable.
To emphasize the strategic role of ontologies in On Demand Systems, we demonstrate the effectiveness of an ontological approach by illustrating its application within a case study. The advantages of semantic technologies shown in the case study include: semantic explicitness, inferencing, modularity, reusability, extensibility, applicability, formal verification, to name but a few.