XML keyword search has attracted a lot of interests with typical search based on lowest common ancestor (LCA). However, in this paper, we show that meaningful answers can be found beyond LCA and should be independent from schema designs of the same data content. Therefore, we propose a new semantics, called CR (Common Relative), which not only can find more answers beyond LCA, but the returned ...

Keyword search in XML documents has recently gained a lot of research attention. Given a keyword query, existing approaches first compute the lowest common ancestors (LCAs) or their variants of XML elements that contain the input keywords, and then identify the subtrees rooted at the LCAs as the answer. In this the paper we study how to use the rich structural relationships embedded in XML docu...

We study how to label the vertices of a tree in such a way that we can decide the distance of two vertices in the tree given only their labels. For trees, Gavoille et al. [7] proved that for any such distance labelling scheme, the maximum label length is at least 1 8 log n−O(log n) bits. They also gave a separatorbased labelling scheme that has the optimal label length Θ(log n · log(Hn(T ))), w...

We present methods that compute generalizations of concepts or individuals described in ontologies written in the Description Logic EL. These generalizations are the basis of methods for ontology design and are the core of concept similarity measures. The reasoning service least common subsumer (lcs) generalizes a set of concepts. Similarly, the most specific concept (msc) generalizes an indivi...

We present a novel self-stabilizing algorithm for minimum spanning tree (MST) construction. The space complexity of our solution is O(log n) bits and it converges in O(n) rounds. Thus, this algorithm improves the convergence time of all previously known self-stabilizing asynchronous MST algorithms by a multiplicative factor Θ(n), to the price of increasing the best known space complexity by a f...

Due to the constantly growing number of information sources, intelligent information retrieval becomes a more and more important task. We model information sources by description logic (DL) terminologies. The commonalities of user-speci ed examples can be computed by the least common subsumer (LCS) operator. However, in some cases this operator delivers too general results. In this article we s...

We investigate the nearest common ancestor (NCA) function in rooted trees. As the main conceptual contribution, the paper introduces universal trees for the NCA function: For a given family of rooted trees, an NCA-universal tree S is a rooted tree such that any tree T of the family can be embedded into S such that the embedding of the NCA in T of two nodes of T is equal to the NCA in S of the e...

This paper describes an approach for representing and manipulating sequences in description logics (DLs). The key idea is to represent sequences using su x trees, then represent the resulting trees in a DL using traditional (tractable) concept and role operators. This approach supports the representation of a range of types of information about a sequence, such as the locations and numbers of o...

We address the problem of labeling the nodes of a tree such that one can determine the identifier of the least common ancestor of any two nodes by looking only at their labels. This problem has application in routing and in distributed computing in peer-to-peer networks. A labeling scheme using Θ(log n)-bit labels has been previously presented by Peleg. By engineering this scheme, we obtain a v...