Using the notions of Q-heaps and fusion trees developed by Fredman and Willard, we develop a faster version of the fractional cascading technique while maintaining the linear space structure. The new version enables sublogarithmic iterative search in the case when we have a search tree and the degree of each node is bounded by O(log n), for some constant > 0, where n is the total size of all th...

We give a new lower bound on the query complexity of any non-adaptive algorithm for testing whether an unknown Boolean function is a k-junta versus ε-far from every k-junta. Our lower bound is that any non-adaptive algorithm must make Ω ( k log k εc log(log(k)/εc) ) queries for this testing problem, where c is any absolute constant < 1. For suitable values of ε this is asymptotically larger tha...

Orthogonal range reporting is one of the classic and most fundamental data structure problems. (2,1,1) query is a 3 dimensional query with two-sided constraint on the first dimension and one sided constraint on each of the 2nd and 3rd dimension. Given a set of N points in three dimension, a particular formulation of such a (2, 1, 1) query (known as four-sided range reporting in threedimension) ...

The research on search log anonymization is ten years old. Over this time, a number of methods to reduce the risks of user identification and disclosure of sensitive information from search log analysis have been proposed. However, the impact of these findings on the behaviour of data owners and publishers has been very limited so far. In this paper, we present a brief overview and a classifica...

The amount and variety of data available electronically has dramatically increased in the last decade; however, data and documents are stored in different ways and do not usually show their internal structure. In order to take full advantage of the topological structure of digital documents, and particularly web sites, their hierarchical organization should be exploited by introducing a notion ...

Amendments to laws are necessary to keep up with the changing needs of the society. Such a process is largely manual, and takes feedbacks from the society for the introduction of an amendment. The Right to information (RTI) Act 2005 gives Indian citizens the opportunity to interact with the government. The present paper discusses how analysis of the RTI system can assist in mining feedbacks tha...

A Longest Common Extension (LCE) query on a text T of length N asks for the length of the longest common prefix of suffixes starting at given two positions. We show that the signature encoding G of size w = O(min(z log N log∗M, N)) [Mehlhorn et al., Algorithmica 17(2):183198, 1997] of T , which can be seen as a compressed representation of T , has a capability to support LCE queries in O(log N ...

Cultural heritage, and other special domains, pose a particular problem for information retrieval: evaluation requires a dedicated test collection that takes the particular documents and information requests into account, but building such a test collection requires substantial human effort. This paper investigates methods of generating a document retrieval test collection from a search engine’...

This paper proposes a manipulation language tailored for OLAP query logs, stemming from the relational algebra. This language is based on binary relations over sequences of queries (called sessions). We propose two such relations allowing to group and order sessions. Examples of expressions in this language illustrate its interest for various user-centric approaches, like query recommendation o...

In this paper we present an analysis of a 280 GB AltaVista Search Engine query log consisting of approximately 1 billion entries for search requests over a period of six weeks. This represents approximately 285 million user sessions, each an attempt to fill a single information need. We present an analysis of individual queries, query duplication, and query sessions. Furthermore we present resu...