Paving the Way to an Effective and Efficient Retrieval of Data over Semantic Overlay Networks

2010 ◽  
pp. 151-175
Author(s):  
Federica Mandreoli ◽  
Riccardo Martoglia ◽  
Wilma Penzo ◽  
Simona Sassatelli ◽  
Giorgio Villani
Keyword(s):  
Query Processing ◽  
Overlay Networks ◽  
Local Data ◽  
System A ◽  
Processing Strategies ◽  
Efficient Retrieval ◽  
Common Interests ◽  
Routing Mechanism ◽  
Indexing Mechanism ◽  
P2p System

In a Peer-to-Peer (P2P) system, a Semantic Overlay Network (SON) models a network of peers whose connections are influenced by the peers’ content, so that semantically related peers connect with each other. This is very common in P2P communities, where peers share common interests, and a peer can belong to more than one SON, depending on its own interests. Querying such a kind of systems is not an easy task: The retrieval of relevant data can not rely on flooding approaches which forward a query to the overall network. A way of selecting which peers are more likely to provide relevant answers is necessary to support more efficient and effective query processing strategies. This chapter presents a semantic infrastructure for routing queries effectively in a network of SONs. Peers are semantically rich, in that peers’ content is modelled with a schema on their local data, and peers are related each other through semantic mappings defined between their own schemas. A query is routed through the network by means of a sequence of reformulations, according to the semantic mappings encountered in the routing path. As reformulations may lead to semantic approximations, we define a fully distributed indexing mechanism which summarizes the semantics underlying whole subnetworks, in order to be able to locate the semantically best directions to forward a query to. In support of our proposal, we demonstrate through a rich set of experiments that our routing mechanism overtakes algorithms which are usually limited to the only knowledge of the peers directly connected to the querying peer, and that our approach is particularly successful in a SONs scenario.

Hedley Bull, states systems and international societies

1987 ◽  
Vol 13 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Adam Watson
Keyword(s):  
International Relations ◽  
International Society ◽  
The Other ◽  
Common Values ◽  
System A ◽  
Common Interests ◽  
Hedley Bull ◽  
Regular Contact

Hedley Bull's contribution to the theory of international relations is considerable; and nowhere more acute than in the distinction which he made between the concept of a system of states and that of an international society. His definitive formulation is set out in Chapter I of The Anarchical Society. ‘Where states are in regular contact with one another, and where in addition there is interaction between them sufficient to make the behaviour of each a necessary element in the calculations of the other, then we may speak of their forming a system.’ ‘A society of states (or international society) exists when a group of states, conscious of certain common interests and common values, form a society in the sense that they conceive themselves to be bound by a common set of rules in their relations with one another, and share in the working of common institutions.’

scholarly journals Efficient Multi Dimensional Nodal Fuzzy Search for Information Management System

2010 ◽  
pp. 97-101
Author(s):  
M Raja Narayana ◽  
B Sasikala ◽  
N Balakrishna
Keyword(s):  
Query Processing ◽  
Information Management ◽  
Experimental Evaluation ◽  
Information Management System ◽  
Three Dimension ◽  
Fuzzy Search ◽  
Processing Strategies ◽  
Fuzzy Query ◽  
Search For Information ◽  
Search Approach

We propose a novel multi-dimensional search approach that allows users to perform fuzzy searches for structure and metadata conditions in addition to keyword conditions. Our techniques individually score each dimension and integrate the three dimension scores into a meaningful unified score. We also design indexes and algorithms to efficiently identify the most relevant files that match multi-dimensional queries. We perform a thorough experimental evaluation of our approach and show that our relaxation and scoring framework for fuzzy query conditions in non content dimensions can significantly improve ranking accuracy. We also show that our query processing strategies perform and scale well, making our fuzzy search approach practical for every day usage.

Pattern-Based Schema Mapping and Query Answering in Peer-to-Peer XML Data Integration System

2011 ◽  
pp. 221-246 ◽  
Author(s):  
Tadeusz Pankowski
Keyword(s):  
Data Integration ◽  
Missing Values ◽  
Peer To Peer ◽  
Query Answering ◽  
Functional Dependencies ◽  
Local Data ◽  
Integration System ◽  
Data Integration System ◽  
P2p System ◽  
High Level

This chapter addresses the problem of data integration in a P2P environment, where each peer stores schema of its local data, mappings between the schemas, and some schema constraints. The goal of the integration is to answer queries formulated against a chosen peer. The answer must consist of data stored in the queried peer as well as data of its direct and indirect partners. The chapter focuses on defining and using mappings, schema constraints, query propagation across the P2P system, and query answering in such scenario. Schemas, mappings, constraints (functional dependencies) and queries are all expressed using a unified approach based on tree-pattern formulas. The chapter discusses how functional dependencies can be exploited to increase information content of answers (by discovering missing values) and to control merging operations and propagation strategies. The chapter proposes algorithms for translating high-level specifications of mappings and queries into XQuery programs, and it shows how the discussed method has been implemented in SixP2P (or 6P2P) system.

Querying and Integrating P2P Deductive Databases

2009 ◽  
pp. 410-416
Author(s):  
Luciano Caroprese ◽  
Sergio Greco ◽  
Ester Zumpano
Keyword(s):  
Query Optimization ◽  
Deductive Databases ◽  
The Other ◽  
Mapping Rules ◽  
System A ◽  
Definition Of ◽  
P2p System

Recently, there have been several proposals that consider the integration of information and the computation of queries in an open-ended network of distributed peers (Bernstein, Giunchiglia, Kementsietsidis, Mylopulos, Serafini, & Zaihrayen, 2002; Calvanese, De Giacomo, Lenzerini, & Rosati, 2004; Franconi, Kuper, Lopatenko, & Zaihrayeu, 2003) as well as the problem of schema mediation and query optimization in P2P (peerto- peer) environments (Gribble, Halevy, Ives, Rodrig, & Suciu, 2001; Halevy, Ives, Suciu, & Tatarinov, 2003; Madhavan & Halevy, 2003; Tatarinov & Halevy, 2004). Generally, peers can both provide or consume data and the only information a peer participating in a P2P system has is about neighbors, that is, information about the peers that are reachable and can provide data of interest. More specifically, each peer joining a P2P system exhibits a set of mapping rules, in other words, a set of semantic correspondences to a set of peers that are already part of the system (neighbors). Thus, in a P2P system, the entry of a new source, or peer, is extremely simple as it just requires the definition of the mapping rules. By using mapping rules as soon as it enters the system, a peer can participate and access all data available in its neighborhood, and through its neighborhood it becomes accessible to all the other peers in the system.

Towards Semantic-Based P2P Reputation Systems

2011 ◽  
pp. 101-119
Author(s):  
Ernesto Damiani ◽  
Marco Viviani
Keyword(s):  
Overlay Networks ◽  
Research Effort ◽  
Peer To Peer ◽  
Reputation Systems ◽  
Shared Resources ◽  
Trust Value ◽  
P2p Systems ◽  
Data Objects ◽  
P2p System ◽  
Simple Features

Peer-to-peer (P2P) systems represent nowadays a large portion of Internet traffic, and are fundamental data sources. In a pure P2P system, since no peer has the power or responsibility to monitor and restrain others behaviours, there is no method to verify the trustworthiness of shared resources, and malicious peers can spread untrustworthy data objects to the system. Furthermore, data descriptions are often simple features directly connected to data or annotations based on heterogeneous schemas, a fact that makes difficult to obtain a single coherent trust value on a resource. This chapter describes techniques where the combination of Semantic Web and peer-to-peer technologies is used for expressing the knowledge shared by peers in a well-defined and formal way. Finally, dealing with Semantic-based P2P networks, the chapter suggests a research effort in this direction, where the association between cluster-based overlay networks and reputation systems based on numerical approaches seems to be promising.

Continuous Join Query Processing over Structured Overlay Networks

2011 ◽  
Vol 467-469 ◽  
pp. 859-861
Author(s):  
Yang Liu ◽  
Ke Jun Zhao ◽  
Yi Hong Qiu ◽  
Qi Liu
Keyword(s):  
Query Processing ◽  
Network Traffic ◽  
Overlay Networks ◽  
Data Flow ◽  
P2p Network ◽  
Distributed Data ◽  
Structured Overlay ◽  
Structured Overlay Networks ◽  
Global Query ◽  
P2p Overlay

P2P network is more suitable for distributed data flow processing. This paper concentrates on how to answer continuous join query in structured p2p overlay networks. In the algorithm proposed, the data that cannot contribute the queries’ results will not be distributed in the network based on global query indices. Experiment shows that the algorithm ensures the availability of join query and network traffic is reduced.

scholarly journals An amateur's introduction to recursive query processing strategies

1986 ◽  
Vol 15 (2) ◽  
pp. 16-52 ◽  
Author(s):  
Francois Bancilhon ◽  
Raghu Ramakrishnan
Keyword(s):  
Query Processing ◽  
Processing Strategies ◽  
Recursive Query
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