Automatic Logical Navigation Among Relations Using Steiner Trees
نویسنده
چکیده
Dekang Lin Department of Computing Science University of Alberta Edmonton, Alberta, Canada T6G 2H1 High-level query languages such as SQL, QUEL have successfully removed the need for physical navigation, but they have failed to provide automatic logical navigation. In this paper, we describe the use of the Steiner Tree (or the shortest connection) as a model for automatic logical navigation among relations. We introduce an efficient approximation algorithm for finding shortest connections. The model is extended to allow for ambiguous words in queries. The capability of this method is demonstrated by a simple database interface which is both easy to build and easy to use. The method may also be imbedded in other query systems as a tool for finding navigation routes.
منابع مشابه
On Approximate Min-Max Theorems for Graph Connectivity Problems by Lap
On Approximate Min-Max Theorems for Graph Connectivity Problems Lap Chi Lau Doctor of Philosophy Graduate Department of Computer Science University of Toronto 2006 Given an undirected graph G and a subset of vertices S ⊆ V (G), we call the vertices in S the terminal vertices and the vertices in V (G) − S the Steiner vertices. In this thesis, we study two problems whose goals are to achieve high...
متن کاملD-STAG: A Formalism for Discourse Analysis Based on SDRT and Using Synchronous TAG
We propose d-stag, a new formalism for the automatic analysis of discourse. The analyses computed by d-stag are hierarchical discourse structures annotated with discourse relations, which are compatible with discourse structures computed in sdrt. A discursive stag grammar pairs up trees anchored by discourse connectives with trees anchored by (functors associated with) discourse relations.
متن کاملOn the configuration space of Steiner minimal trees
Among other results, we prove the following theorem about Steiner minimal trees in ddimensional Euclidean space: if two finite sets in R have unique and combinatorially equivalent Steiner minimal trees, then there is a homotopy between the two sets that maintains the uniqueness and the combinatorial structure of the Steiner minimal tree throughout the homotopy.
متن کاملNormalization by evaluation for λ→2
We show that the set-theoretic semantics for λ→2 is complete by inverting evaluation using decision trees. This leads to an implementation of normalization by evaluation which is witnessed by the source of part of this paper being a literate Haskell script. We show the correctness of our implementation using logical relations.
متن کاملNormalization by evaluation for λ
We show that the set-theoretic semantics of λ—simply typed lambda calculus with a boolean type but no type variables—is complete by inverting evaluation using decision trees. This leads to an implementation of normalization by evaluation which is witnessed by the source of part of this paper being a literate Haskell script. We show the correctness of our implementation using logical relations.
متن کامل