Top-k queries have attracted interest in many different areas like network and system monitoring, information retrieval, sensor networks, and so on. Since today many applications issue top-k queries on distributed and outsourced databases, authentication of top-k query results becomes more important. This paper addresses the problem of authenticated top-k aggregation queries (e.g. “find the k o...

Let K be an n-dimensional local field, L/K a finite abelian extension. Define a filtration on Gal(L/K) (cf. [H], [F, sect. 4]) by Gal(L/K) = Υ L/K(UiK top n (K) +NL/KK top n (L)/NL/KK top n (L)), i ∈ Z n + , where UiK top n (K) = {Ui} ·K top n−1(K), Ui = 1 + PK(i), Υ L/K :K top n (K)/NL/KK top n (L) →̃ Gal(L/K) is the reciprocity map. Then for a subextension M/K of L/K Gal(M/K) = Gal(L/K) Gal(L/...

Efficient processing of top-k queries on multidimensional grids is a common requirement in information retrieval and data mining, for example in OLAP cubes. We introduce a data structure, the K-treap, that represents grids in compact form and supports efficient prioritized range queries. We compare the K-treap with state-of-the-art solutions on synthetic and real-world datasets, showing that it...

Efficient processing of top-k queries has become a classical research area. Fagin et al. proposed the “middleware cost” for a top-k query algorithm. In some scenario, there is no way to perform a random access, and Fagin et al. proposed NRA (No Random Access) algorithm for that. In this paper, we investigate the intrinsic relation between top-k queries and K-skyband queries. Based on that relat...

Information retrieval from textual data focuses on the construction of vocabularies that contain weighted term tuples. Such vocabularies can then be exploited by various text analysis algorithms to extract new knowledge, e.g., top-k keywords, top-k documents, etc. Topk keywords are casually used for various purposes, are often computed on-the-fly, and thus must be efficiently computed. To compa...

We engineer a self-index based retrieval system capable of rank-safe evaluation of top-k queries. The framework generalizes the GREEDY approach of Culpepper et al. (ESA 2010) to handle multiterm queries, including over phrases. We propose two techniques which significantly reduce the ranking time for a wide range of popular Information Retrieval (IR) relevance measures, such as TF×IDF and BM25....