3.4 Peer-to-Peer and Semantic Web
From semanticweb.org
Main Contributors: Walter Binder, Heiner Stuckenschmidt, Frank van Harmelen. See the list of contributors
- 1. CURRENT TRENDS IN SEMANTIC WEB (In the following part we intend to identify the state of the art of Semantic Web based theories, methods, applications and tools in your research field.)
- 1.1. One or more examples (case studies) in which semantic web has been used.
Name of the institutions:IBIT Industry / sector: Tourism Business activities improved by the SW solutions: Experience Management Research Needs: Collaborative Ontology Building; Automatic Document Annotation Name of the project:SWAP Tools and applications implemented in the project:XAROP
- 1.2. The first 4 Semantic Web based tools used in your research fields.
Name: P-Grid Website: http://www.p-grid.org/ Main characteristics: P2P Data management system supporting semantic overlays and limited forms of ontology mappings. Open problems: Limited Representation Language -- medium relevance -- will be solved in the short term Only simple schema mappings -- medium relevance -- will be solved in the medium term No schema-based reasoning -- high relevance -- will be solved in the short term Name: Edutella Website: http://edutella.jxta.org/ Main characteristics: RDF-Based P2P-data management systems with schema based routing indices and efficient topologies Open problems: No schema reasoning -- high relevance -- will be solved in the short term Limited use of ontologies -- very high relevance -- will be solved in the short term Name: DRAGO Website: http://drago.itc.it/ Main characteristics: P2P ontology infrastructure supporting subusmption reasoning and instance retrieval in C-OWL ontologies Open problems: No complex queries supported -- high relevance -- will be solved in the short term Large scale data management -- high relevance -- will be solved in the medium term Scalability not tested -- medium relevance -- will be solved in the short term
- 1.3. A short summary of the first 3 best papers in the field.
Reference: Daswani, N., Garcia-Molina, H., and Yang, B. (2003). Open problems in datasharing peer-to-peer systems. In Proceedings of the 9th International Conference on Database Theory (ICDT), Siena, Italy. Short abstract: The paper summarizes the state of the art in P2P data management systems and discusses fundamental problems. The discussion is not focussed on semantic web related issues but it provides an excellent overview of the key aspects such as search strategies, expressiveness of the query language, robustness and reliability that need to be addressed by P2P solutions. The open problems identified provide a good insight in what the role of semantic web technologies can be in the context of P2P environments.
Reference: Bouquet, P., Giunchiglia, F., van Harmelen, F., Serafini, L., and Stuckenschmidt, H. (2004). Contextualizing ontologies. Journal on Web Semantics, 1(4). Short abstract:The paper discusses the design of the web ontology language in the context of its ability to capture different points of view in heterogeneous distributed systems. The authors show that the formal semantics of OWL make fundamental assumptions that do not hold in P2P like environments. The authors propose an extension to OWL more suited to P2P systems that is based on local models that are only connected by rather weak mapping rules that can be used to propagate information between the ontologies of different peers.
Reference: Amir, E. and McIlraith, S.,``Partition-Based Logical Reasoning for First-Order and Propositional Theories", Accepted for Publication in Aritificial Intelligence. Short abstract: While not explicitly addressing P2P systems, this paper introduces a fundamental theory and methods for performing logical reasoning in a distributed setting. The authors present methods for optimally splitting up logical theories. They present sound and complete algorithms for propositional and first order logic and report experiments in distributed reasoning that clearly show that localization of reasoning can significantly improve the performance.
- 1.4. A short list of open problems in theories and methods.
Modularity and distribution: high relevance -- will be solved in the short term Matching and Alignment: high relevance -- will be solved in the long term Scalability: very high relevance -- will be solved in the medium term
- 2. TRENDS ON THEORIES AND METHODS, SERVICES AND APPLICATIONS
- 2.1. Research projects in which contributors are involved, along with a general description. Moreover, suggest for each project the possible future uses and applications related to the Semantic Web, the acceptance and diffusion in each period considered, the benefits, and the problems that will be probably occur.
Name of the project: Semantic Information Porcessing in complex distributed domains Type: Basic Research Grant of the German Science Foundation Duration: 5 Years Partners: Research Institution: University of Mannheim Industrial Partners: none Core activities: Ontology Partitioning -- high relevance -- will be solved in the short term Distributed Reasoning -- very high relevance -- will be solved in the medium term Semantic Search -- high relevance -- will be solved in the short and medium term Market opportunities: no one is identified. This is basic research and not aimed at producing tools for industrial use. Problems and missing tools: Reasoning System for Mappings -- high relevance -- will be solved in the short term Decentralized and Parallel Inference engines -- high relevance -- will be solved in the medium term Problems – Semantic Web culture is missing: Reasoning is assumed to be done locally -- high relevance -- will be solved in the short term Convincing Use Cases are missing -- very high relevance -- will be solved in the short term
Name of the project: KnowledgeWeb (KW) Type: 6th European Framework Network of Excellence Duration: 4 Years Partners: Research Institution: see the portal of KW project Industrial Partners: see the industrial protal of KW project Core activities: Scalability -- very high relevance -- will be solved in the medium term Heterogeneity -- very high relevance -- will be solved in the long term Market opportunities: no one is identified. Technical problems: Robust Reasoning Methods -- high relevance -- will be solved in the short term Evaluation Frameworks for automatic mapping -- very high relevance -- will be solved in the medium term Problems – Semantic Web culture is missing: Little integration of light/weight and heavy weight approaches -- high relevance -- will be solved in the medium term Clear distinction from previous work in databases missing -- very high relevance -- will be solved in the short term
Name of the project: NEON Type: Integrated Project Duration: 4 Years Partners: Research Institution: Open University UK, AIFB Karlsruhe, Politechnical University of Madrid, Josef Stefan Institute, INRIA Grenoble, University of Sheffield, CNR Italy Industrial Partners: Software AG, Isoco, Ontoprise, Atos Origin Core activities: Dynamics of Networked Ontologies -- high relevance -- will be solved in the medium term Context Sensitivity for networked ontologies -- medium relevance -- will be solved in the medium term Market opportunities: no one is identified. Technological Problems (missing theories and methods): Change management for mappings -- high relevance -- will be solved in the medium term Requirements-driven mapping -- high relevance -- will be solved in the short term Problems – Missing tools: Editors for interconnected ontologies will be solved in the short time
- 2.2. Some topics that will not be solved in short and medium term, for each of them there is a short explanation of the main reasons and (if possible) some references.
Topics: Automatic Matching Reason: The problem of heterogeneous representations is one of the core problems of computer science. Despite intensive research in different areas there are no uncontroversial solutions. There is doubt whether this problem can ever be solved completely, because the intended meaning of a representation is often not even known any more or heavily depends on the context. References: none
Topics: Scalable Reasoning for expressive Ontologies Reason: Reasoning in expressive languages like OWL is inherently intractable. Even approaches that work under perfect circumstances (complete and consistent centralized knowledge) cannot always guarantee to solve a problem in acceptable time. Real breakthroughs in efficiency so far have only been achieved in the area of propositional logic where the run time complexity can be reduced to linear time using preprocessing techniques. For expressive languages such a breakthrough is unlikely. References: none
- 3. TRENDS ON TOOLS
- 3.1. A list of the most relevant semantic based demos in the area.
Name: Bibster Website: http://bibster.semanticweb.org Description: see the web page References: P. Haase, J. Broekstra, M.Ehrig, M. Menken, P.Mika, M. Plechawski, P. Pyszlak, B. Schnizler, R. Siebes, S. Staab, C. Tempich Bibster - A Semantics-Based Bibliographic Peer-to-Peer System. Proceedings of the International Semantic Web Conference (ISWC2004), November 9-11, 2004, Hiroshima, Japan Main features: Exchange of Bibliographic data -- normal relevance Topic-based search -- high relevance Duplicate detection -- normal relevance Open problems: Single Centralized Ontology -- high relevance -- will be solved in the medium term No schema-aware querying -- high relevance -- will be solved in the short term User Acceptance -- very high relevance -- will be solved in the short term
- 3.2. A short description of tools that are still missing. A description of business activities and problems they should solve, will be provided.
- 4.Please fell free to add any comment or suggestion.
At the moment, developments in this area seem to be hampered by the fact that people either focus on distributed solutions with very little semantics or at semantic solutions with almost no decentralization.
