Web Search Engines (WSEs) have stored in their query logs information about users since they started to operate. This information often serves many purposes. The primary focus of this tutorial is to introduce to the discipline of query log mining. We will show its foundations, by giving a unified view on the literature on query log analysis, and also present in detail the basic algorithms and t...

Given a simple polygon P in the plane, we present new algorithms and data structures for computing the weak visibility polygon from any query line segment in P . We build a data structure in O(n) time and O(n) space that can compute the visibility polygon for any query line segment s in O(k log n) time, where k is the size of the visibility polygon of s and n is the number of vertices of P . Al...

Let D = {d1, d2, ..., dD} be a given collection of D string documents of total length n. We consider the problem of indexing D such that, whenever two patterns P and P− comes as an online query, we can list all those documents containing P but not P−. Let t represent the number of such documents. An index proposed by Fischer et al. (LATIN, 2012) can answer this query in O(|P|+ |P−|+ t+ √ n) tim...

This paper considers the problem of computing the weak visibility polygon (WVP) of any query line segment pq (or WVP(pq)) inside a given simple polygon P. We present an algorithm that preprocesses P and creates a data structure from which WVP(pq) is efficiently reported in an output sensitive manner. Our algorithm needs O(n log n) time and O(n) space in the preprocessing phase to report WVP(pq)...

A new effective log-based approach for interactive Web search is presented in this paper. The most important feature of the proposed approach is that the suggested terms corresponding to the user’s query are extracted from similar query sessions, rather than from the contents of the retrieved documents. The experiment results demonstrate that this approach has a great potential in developing mo...

Let S be a set of n points in the plane. We present a method where, using O(n log n) time and space, S can be pre-processed into a data structure such that given an axis-parallel query rectangle q, we can report the radius of the smallest enclosing disk of the points lying in S ∩ q in O(log n) time per query.

Reverse nearest neighbor queries are defined as follows: Given an input point-set P , and a query point q, find all the points p in P whose nearest point in P ∪ {q} \ {p} is q. We give a data structure to answer reverse nearest neighbor queries in fixed-dimensional Euclidean space. Our data structure uses O(n) space, its preprocessing time is O(n log n), and its query time is O(log n).

Web search logs are valuable and widely used for improving Information Retrieval (IR) research. However, these query logs contain sensitive data, which makes them difficult to be released directly even for research purposes. More companies can release their query logs if adequate privacy protection can be placed. This workshop paper introduces our research project on this privacy preserving que...

In this paper we consider the problem of computing the closest point to the boundary of a circle among a set S of n points. We present two algorithms to solve this problem. One algorithm runs in O(n) preprocessing time and space and O(log n) query time. The other algorithm runs in O(n ) preprocessing time and O(n log n) space and O(n ) query time. Thus we exhibit a trade-off between preprocessi...