We consider a setting with numerous location-aware moving objects that communicate with a central server. Assuming a set of focal points of interest, we aim at continuously monitoring object orientations and hence detect situations where many objects ...

Querying XML data is based on the specification of structural patterns which in practice are formulated using XPath. Usually, these structural patterns are in the form of trees (Tree-Pattern Queries --- TPQs). Requirements for flexible querying of XML ...

Several applications in areas such as biochemistry, GIS, involve storing and querying large volumes of sequential data stored as path collections. There is a number of interesting queries that can be posed on such data. This work focuses on ...

In a world of wide-scale information sharing, the decentralized coordination has to consolidate a variety of heterogeneity. Shared data are described in different formats, i.e. data structures, values and schemas. Querying manifold such sources entails ...

As we move from a Web of data to a Web of services, enhancing the capabilities of the current Web search engines with effective and efficient techniques for Web services retrieval and selection becomes an important issue. Traditionally, the relevance ...

Sharing structured data in a P2P network is a challenging problem, especially in the absence of a mediated schema. The standard practice of answering a consecutively rewritten query along the propagation path often results in significant loss of information. ...

The peer-to-peer (P2P) paradigm has become very popular for storing and sharing information in a totally decentralized manner. At first, research focused on P2P systems that host 1D data. Nowadays, the need for P2P applications with multidimensional ...

Nowadays, huge volumes of data are organized or exported in tree-structured form. Querying capabilities are provided through tree-pattern queries. The need for querying tree-structured data sources when their structure is not fully known, and the need ...

The wavelet decomposition is a proven tool for constructing concise synopses of large data sets that can be used to obtain fast approximate answers. Existing research studies focus on selecting an optimal set of wavelet coefficients to store so as to ...

We are interested in the problem of data sharing in overlay networks that have a social structure, i.e. participants are linked and exchange data with others w.r.t. the similarity of their data semantics. In this paper we propose a methodology to produce ...