Conference on Advanced Information Systems Engineering, 2000
Abstract. Peer-to-peer (P2P) networks have become,an important infrastructure during the last yea... more Abstract. Peer-to-peer (P2P) networks have become,an important infrastructure during the last years. Using P2P networks,for distributed information systems allows us to shift the focus from centrally organized to distributed information systems where all peers can provide and have access to information. In previous papers, we have described an RDF-based P2P infrastructure called Edutella which is a specific example,of a more,advanced,approach,to
In this paper we propose to use schema-based peer-to-peer systems for the exchange of scienitific... more In this paper we propose to use schema-based peer-to-peer systems for the exchange of scienitific documents. Compared with recent file sharing networks highly domain-oriented sci- entific documents are shared in relatively small research com- munities with tight internal and only a few external connec- tions. The documents are annotated with small a but well- defined sets of metadata using standard
this paper.13 Schema-Based RoutingP2P networks that broadcast all queries to all peers don'ts... more this paper.13 Schema-Based RoutingP2P networks that broadcast all queries to all peers don'tscale. To take the semantic heterogeneity of schemabasedP2P networks into account, we advocate a superpeertopology for these networks and the use of indicesat these super-peers to address scalability requirements.The super-peer network constitutes the "backbone" of theP2P network taking care of message routing and integration/mediation of metadata
While Web Services already provide distributed operation execution, the registration and discover... more While Web Services already provide distributed operation execution, the registration and discovery with UDDI is still based on a centralized design. In this paper we show to build a distributed discovery service, based on a peer-to-peer infrastructure. Furthermore, we use DAML-S service descriptions to provide enhanced semantic search capabilities. Our prototype implementing this approach based on the peer- to-peer infrastructure
Proceedings of the 34th international ACM SIGIR conference on Research and development in Information - SIGIR '11, 2011
ABSTRACT Result diversification is an effective method to reduce the risk that none of the return... more ABSTRACT Result diversification is an effective method to reduce the risk that none of the returned results satisfies a user's query intention. It has been shown to decrease query abandonment substantially. On the other hand, computing an optimally diverse set is NP-hard for the usual objectives. Existing greedy diversification algorithms require random access to the input set, rendering them impractical in the context of large result sets or continuous data. To solve this issue, we present a novel diversification approach which treats the input as a stream and processes each element in an incremental fashion, maintaining a near-optimal diverse set at any point in the stream. Our approach exhibits a linear computation and constant memory complexity with respect to input size, without significant loss of diversification quality. In an extensive evaluation on several real-world data sets, we show the applicability and efficiency of our algorithm for large result sets as well as for continuous query scenarios such as news stream subscriptions.
Abstract. Peer-to-peer (P2P) networks have become,an important infrastructure during the last yea... more Abstract. Peer-to-peer (P2P) networks have become,an important infrastructure during the last years. Using P2P networks,for distributed information systems allows us to shift the focus from centrally organized to distributed information systems where all peers can provide and have access to information. In previous papers, we have described an RDF-based P2P infrastructure called Edutella which is a specific example,of a more,advanced,approach,to P2P net- works called schema-based,peer-to-peer networks. Schema-based P2P networks have a number,of advantages compared,with simpler P2P networks such as Nap- ster or Gnutella. Instead of prescribing one global schema to describe content, they support arbitrary metadata schemas,and ontologies (crucial for the Seman- tic Web). Thereby they allow complex,and extendable descriptions of resources thus introducing dynamic behavior to the former fixed and limited descriptions, and can provide complex,query facilities against these metadata instead of simple keyword-based searches. In this paper we will elaborate topologies, indices and query routing strategies for efficient query distribution in such networks. Our work is based on the concept of super-peer networks which provide better scalability compared,to traditional P2P networks. By adapting existing concepts of mediator-based information systems to super-peer based networks, as we will show in this paper, they are able to support sophisticated routing, clustering and mediation strategies based on the metadata schemas,and attributes. The resulting routing indices can be built using local clustering policies and support local mediation and transformation rules between heterogeneous schemas, and we sketch some first ideas for implementing these advanced,functionalities as well.
Conference on Advanced Information Systems Engineering, 2000
Abstract. Peer-to-peer (P2P) networks have become,an important infrastructure during the last yea... more Abstract. Peer-to-peer (P2P) networks have become,an important infrastructure during the last years. Using P2P networks,for distributed information systems allows us to shift the focus from centrally organized to distributed information systems where all peers can provide and have access to information. In previous papers, we have described an RDF-based P2P infrastructure called Edutella which is a specific example,of a more,advanced,approach,to
In this paper we propose to use schema-based peer-to-peer systems for the exchange of scienitific... more In this paper we propose to use schema-based peer-to-peer systems for the exchange of scienitific documents. Compared with recent file sharing networks highly domain-oriented sci- entific documents are shared in relatively small research com- munities with tight internal and only a few external connec- tions. The documents are annotated with small a but well- defined sets of metadata using standard
this paper.13 Schema-Based RoutingP2P networks that broadcast all queries to all peers don'ts... more this paper.13 Schema-Based RoutingP2P networks that broadcast all queries to all peers don'tscale. To take the semantic heterogeneity of schemabasedP2P networks into account, we advocate a superpeertopology for these networks and the use of indicesat these super-peers to address scalability requirements.The super-peer network constitutes the "backbone" of theP2P network taking care of message routing and integration/mediation of metadata
While Web Services already provide distributed operation execution, the registration and discover... more While Web Services already provide distributed operation execution, the registration and discovery with UDDI is still based on a centralized design. In this paper we show to build a distributed discovery service, based on a peer-to-peer infrastructure. Furthermore, we use DAML-S service descriptions to provide enhanced semantic search capabilities. Our prototype implementing this approach based on the peer- to-peer infrastructure
Proceedings of the 34th international ACM SIGIR conference on Research and development in Information - SIGIR '11, 2011
ABSTRACT Result diversification is an effective method to reduce the risk that none of the return... more ABSTRACT Result diversification is an effective method to reduce the risk that none of the returned results satisfies a user's query intention. It has been shown to decrease query abandonment substantially. On the other hand, computing an optimally diverse set is NP-hard for the usual objectives. Existing greedy diversification algorithms require random access to the input set, rendering them impractical in the context of large result sets or continuous data. To solve this issue, we present a novel diversification approach which treats the input as a stream and processes each element in an incremental fashion, maintaining a near-optimal diverse set at any point in the stream. Our approach exhibits a linear computation and constant memory complexity with respect to input size, without significant loss of diversification quality. In an extensive evaluation on several real-world data sets, we show the applicability and efficiency of our algorithm for large result sets as well as for continuous query scenarios such as news stream subscriptions.
Abstract. Peer-to-peer (P2P) networks have become,an important infrastructure during the last yea... more Abstract. Peer-to-peer (P2P) networks have become,an important infrastructure during the last years. Using P2P networks,for distributed information systems allows us to shift the focus from centrally organized to distributed information systems where all peers can provide and have access to information. In previous papers, we have described an RDF-based P2P infrastructure called Edutella which is a specific example,of a more,advanced,approach,to P2P net- works called schema-based,peer-to-peer networks. Schema-based P2P networks have a number,of advantages compared,with simpler P2P networks such as Nap- ster or Gnutella. Instead of prescribing one global schema to describe content, they support arbitrary metadata schemas,and ontologies (crucial for the Seman- tic Web). Thereby they allow complex,and extendable descriptions of resources thus introducing dynamic behavior to the former fixed and limited descriptions, and can provide complex,query facilities against these metadata instead of simple keyword-based searches. In this paper we will elaborate topologies, indices and query routing strategies for efficient query distribution in such networks. Our work is based on the concept of super-peer networks which provide better scalability compared,to traditional P2P networks. By adapting existing concepts of mediator-based information systems to super-peer based networks, as we will show in this paper, they are able to support sophisticated routing, clustering and mediation strategies based on the metadata schemas,and attributes. The resulting routing indices can be built using local clustering policies and support local mediation and transformation rules between heterogeneous schemas, and we sketch some first ideas for implementing these advanced,functionalities as well.
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Papers by Wolf Siberski