Alejandro Salinger

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The intersection of large ordered sets is a common problem in the context of the evaluation of boolean queries to a search engine. In this article, we propose several improved algorithms for computing the intersection of sorted arrays, and in particular for searching sorted arrays in the intersection context. We perform an experimental comparison with the(More)
This work presents an experimental comparison of intersection algorithms for sorted sequences, including the recent algorithm of Baeza-Yates. This algorithm performs on average less comparisons than the total number of elements of both inputs (n and m respectively) when n = αm (α > 1). We can find applications of this algorithm on query processing in Web(More)
We design a succinct full-text index based on the idea of Huffmancompressing the text and then applying the Burrows-Wheeler transform over it. The resulting structure can be searched as an FM-index, with the benefit of removing the sharp dependence on the alphabet size, σ, present in that structure. On a text of length n with zero-order entropy H0, our(More)
We present the first adaptive data structure for two-dimensional orthogonal range search. Our data structure is adaptive in the sense that it gives improved search performance for data with more inherent sortedness. Given n points in the plane, it can answer range queries in O(k logn+m) time, where m is the number of points in the output and k is the(More)
Traditional paging models seek algorithms that maximize their performance while using the maximum amount of cache resources available. However, in many applications this resource is shared or its usage involves a cost. In this work we introduce the Minimum Cache Usage problem, which is an extension to the classic paging problem that accounts for the(More)
Paging for multicore processors extends the classical paging problem to a setting in which several processes simultaneously share the cache. Recently, Hassidim [6] studied cache eviction policies for multicores under the traditional competitive analysis metric, showing that LRU is not competitive against an offline policy that has the power of arbitrarily(More)
Over the last five years, major microprocessor manufacturers have released plans for a rapidly increasing number of cores per microprossesor, with upwards of 64 cores by 2015. In this setting, a sequential RAM computer will no longer accurately reflect the architecture on which algorithms are being executed. In this paper we propose a model of low degree(More)
Given a set D of m unit disks and a set P of n points in the plane, the discrete unit disk cover problem is to select a minimum cardinality subset D′ ⊆ D to cover P. This problem is NP-hard [14] and the best ∗ † ‡ § ¶ ‖
Given m unit disks and n points in the plane, the discrete unit disk cover problem is to select a minimum subset of the disks to cover the points. This problem is NP-hard [11] and the best previous practical solution is a 38-approximation algorithm by Carmi et al. [4]. We first consider the line-separable discrete unit disk cover problem (the set of disk(More)