This paper reports on a transaction log analysis of the type and topic of search queries entered into the search engine Google (Australia). Two aspects, in particular, set this apart from previous studies: the sampling and analysis take account of the distribution of search queries, and lifestyle information of the searcher was matched with each search query. A surprising finding was that there...

With the ever growing use of XML as a data representation format, we see an increasing need for robust, high performance XML database systems. While most of the recent work focuses on efficient XML query processing, XML databases also need to support efficient updates. To speed up query processing, various labeling schemes have been proposed. However, the vast majority of these schemes have poo...

We propose a data structure for finding the exact nearest neighbors in 3D in approximately O(log(log(N)) time. In contrast to standard approaches such as k-d-trees, the query time is independent of the location of the query point and the distribution of the data set. The method uses a hierarchical voxel approximation of the data point’s Voronoi cells. This avoids backtracking during the query p...

web search engines are one of the most popular tools on the internet which are widely-used by expert and novice users. constructing an adequate query which represents the best specification of users’ information need to the search engine is an important concern of web users. query expansion is a way to reduce this concern and increase user satisfaction. in this paper, a new method of query expa...

The Largest Empty Circle problem seeks the largest circle centered within the convex hull of a set P of n points in R2 and devoid of points from P . In this paper, we introduce a query version of this well-studied problem. In our query version, we are required to preprocess P so that when given a query line Q, we can quickly compute the largest empty circle centered at some point on Q and withi...

In this paper we revisit the dynamic dictionary matching problem, which asks for an index for a set of patterns P1, P2, . . . , Pk that can support the following query and update operations efficiently. Given a query text T , we want to find all the occurrences of of these patterns; furthermore, as the set of patterns may change over time, we also want to insert or delete a pattern. The major c...

User-generated Structured Query Language (SQL) queries are a rich source of information for database analysts, information scientists, and the end users of databases. In this study a group of scientists in astronomy and computer and information scientists work together to analyze a large volume of SQL log data generated by users of the Sloan Digital Sky Survey (SDSS) data archive in order to be...

This invited paper summarizes our results on the “independent range sampling” problem in the RAM computation model. The input is a set P of n points in R. Given an interval q = [x, y] and an integer t ≥ 1, a query returns t elements uniformly sampled (with/without replacement) from P ∩ q. The sampling result must be independent from those returned by the previous queries. The objective is to st...

In this paper, we explore worst-case solutions for the problems of single and multiple matching on strings in the word RAM model with word length w. In the first problem, we have to build a data structure based on a pattern p of length m over an alphabet of size σ such that we can answer to the following query: given a text T of length n, where each character is encoded using log σ bits return ...

In this paper, we consider the problem of computing the weak visibility (WV ) of a query line segment inside a simple polygon. Our algorithm first preprocesses the polygon and creates data structures from which any WV query is answered efficiently in an output sensitive manner. In our solution, the preprocessing is performed in time O(n log n) and the size of the constructed data structure is O...