1,721,072 research outputs found
A state of art survey on zz-structures
Full text linkZz-structures are particular data structures capable of representing both hypertextual information and contextual interconnections among different information. The focus of this paper is to stimulate new research on this topic, by providing, in a state of the art survey, a short description and comparison of all the material that, to the best of our knowledge, is related to zz-structures: informal and formal descriptions, implementations, languages, demonstrations, projects and applitudes of zz-structures; in fact, despite their large use in different fields, the literature lacks of an exhaustive and up-to-date description of them
A formal description of zz-structures
Full text linkThe focus of this paper is on particular and innovative structures for storing, linking and manipulating information: The zz-structures. In the last years, we worked at the formalization of these structures, retaining that the description of the formal aspects can provide a better understanding of them, and can also stimulate new ideas, projects and research. This work presents our contribution for a deeper discussion on zz-structures
APPROXIMATE MATCHING FOR 2 FAMILIES OF TREES
No full textAbstractWe study approximate matching between h-ary trees (ordered trees whose nodes have exactly h sons) and ordered arbitrary trees, using a string representation of trees. For two h-ary trees P, T, the subtree distance is the number of subtrees to be inserted in P in place of empty nodes, or to be deleted from P, to obtain T. We consider the problem of finding all the occurrences of P in T, with bounded distance k. A known sequential solution requires O(h|P| + h|T| + k|T|) time. We show that the problem can be solved in O(log h + log|P| + log|T| + k) parallel time, in a CRCW-PRAM with O(h(|P| + |T|)) processors. For arbitrary ordered trees we solve a version of the classical tree pattern matching problem. We define the leaf distance between two trees P, T as the total number of subtrees to be inserted in P in place of its leaves, or to be deleted from P leaving leaves in their place, to obtain T. We show how all the occurrences of P as a subtree of T, with bounded distance k, can be determined in O(|P| + k|T|) sequential time, and in O(log|P| + log|T| + k) parallel time in a CRCW-PRAM with O(|P| + |T|) processors. We also discuss an extension of the above problems to labelled trees
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