DEFINITION Spatial join operation is used to combine two or more datasets with respect to a spatial predicate. The predicate can be a combination of directional, distance, and topological spatial relations. In the case of nonspatial joins, the joining attributes must be of the same type, but for spatial joins they can be of different types. Usually each spatial attribute is represented by its m...

 Abstract— Signature technique for multi-key indexing is proposed for flexible searching in the area of database. In this paper, the signature technique called the Join Signature file is presented to cover graph aggregation hierarchy. The structure of Join Signature is flexible enough so that the predicate can occur at any classes in the hierarchy and the target can be anywhere in the graph ag...

A conjecture concerning perfect graphs asserts that if for a Berge graph G the following three conditions hold: 1. neither G, nor Ḡ has an even pair; 2. neither G, nor Ḡ has a stable cutset; 3. neither G, nor Ḡ has a star-cutset, then G or Ḡ is diamond-free. We show that this conjecture is not valid and that, in a way, every weaker version is false too. To this end, we construct a class of perf...

This paper presents the results of an experimental evaluation of the performance of three main algorithms for transitive closure: Seminaive, Smart and Blocked Warren. The algorithms have been implemented using a variety of join methods (block nested-loops and hash-join), disk-based and memory-based data structures and buffer replacement strategies. The algorithms were tested on several graphs, ...

Let G = (V,E) be a nontrivial, finite, and connected graph. A function c from E to {1,2,...,k},k ∈ N, can considered as rainbow k-coloring if every two vertices x y in has an x- path. Therefore, no path's edges receive the same color; this condition is called “rainbow path”. The smallest positive integer k, designated by rc(G), connection number. Thus, k-coloring. Meanwhile, strong within for h...