We present our views on the CLEF log file analysis task. We argue for a task definition that focuses on the semantic enrichment of query logs. In addition, we discuss how additional information about the context in which queries are being made could further our understanding of users’ information seeking and how to better facilitate this process.

Let D be a collection of D documents, which are strings over an alphabet of size σ, of total length n. We describe a data structure that uses linear space and and reports k most relevant documents that contain a query pattern P , which is a string of length p packed in p/ logσ n words, in time O(p/ logσ n+k). This is optimal in the RAM model in the general case where logD = Θ(log n), and involv...

Characterizing user’s intent and behaviour while using a retrieval information tool (e.g a search engine) is a key question on web research, as it hold the keys to know how the users interact, what they are expecting and how we can provide them information in the most beneficial way. Previous research has focused on identifying the average characteristics of user interactions. This paper propos...

We present in this paper fast algorithms for the D dominance reporting and counting problems and generalize the results to the d dimensional case Our D dominance reporting algorithm achieves O log n log log n f query time using O n log n space where f is the number of points satisfying the query and is an arbitrarily small constant For the D dominance counting problem which is equivalent to the...

We present in this paper fast algorithms for the 3-D dominance reporting and counting problems, and generalize the results to the d-dimensional case. Our 3-D dominance reporting algorithm achieves O(log n= log log n + f) 1 query time using O(n log n) space , where f is the number of points satisfying the query and > 0 is an arbitrarily small constant. For the 3-D dominance counting problem (whi...

We consider the problem of reporting convex hull points in an orthogonal range query in two dimensions. Formally, let P be a set of n points in R. A point lies on the convex hull of a point set S if it lies on the boundary of the minimum convex polygon formed by S. In this paper, we are interested in finding the points that lie on the boundary of the convex hull of the points in P that also fal...

We consider approximate distance oracles for edge-weighted n-vertex undirected planar graphs. Given fixed ǫ > 0, we present a (1 + ǫ)-approximate distance oracle with O(n(log logn)) space and O((log logn)) query time. This improves the previous best product of query time and space of the oracles of Thorup (FOCS 2001, J. ACM 2004) and Klein (SODA 2002) from O(n log n) to O(n(log log n)).

We present a planar point location structure for a convex subdivision S. Given a query sequence of length m, the total running time is O(OPT + m log log n + n), where n is the number of vertices in S and OPT is the minimum time required by any linear decision tree for answering planar point location queries in S to process the same query sequence. The running time includes the preprocessing tim...

The Web is a huge read-write information space where many items such as documents, images or other multimedia can be accessed. In this context, several information technologies have been developed to help users to satisfy their searching needs on the Web, and the most used are search engines. Search engines allow users to find Web resources formulating queries (a set of terms) and reviewing a l...

Let D be a collection of D documents, which are strings over an alphabet of size σ, of total length n. We describe a data structure that uses linear space and and reports k most relevant documents that contain a query pattern P , which is a string of length p, in time O(p/ log σ n+k), which is optimal in the RAM model in the general case where lgD = Θ(logn), and involves a novel RAM-optimal suf...