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Document retrieval is one of the most challenging tasks in Information Retrieval. It requires handling longer contexts, often resulting in higher query latency and increased computational overhead. Recently, Learned Sparse Retrieval (LSR)…

Information Retrieval · Computer Science 2025-04-09 Emmanouil Georgios Lionis , Jia-Huei Ju

Big research efforts have been devoted to efficiently manage spatio-temporal data. However, most works focused on vectorial data, and much less, on raster data. This work presents a new representation for raster data that evolve along time…

Data Structures and Algorithms · Computer Science 2018-10-26 Ana Cerdeira-Pena , Guillermo de Bernardo , Antonio Fariña , Jose R. Parama , Fernando Silva-Coira

In a dynamic retrieval system, documents must be ingested as they arrive, and be immediately findable by queries. Our purpose in this paper is to describe an index structure and processing regime that accommodates that requirement for…

Information Retrieval · Computer Science 2023-01-12 Alistair Moffat , Joel Mackenzie

In this paper we describe compressed indexes that support pattern matching queries for strings with wildcards. For a constant size alphabet our data structure uses $O(n\log^{\varepsilon}n)$ bits for any $\varepsilon>0$ and reports all…

Data Structures and Algorithms · Computer Science 2014-01-06 Moshe Lewenstein , Yakov Nekrich , Jeffrey Scott Vitter

Spaced seeds are important tools for similarity search in bioinformatics, and using several seeds together often significantly improves their performance. With existing approaches, however, for each seed we keep a separate linear-size data…

Data Structures and Algorithms · Computer Science 2014-03-11 Travis Gagie , Giovanni Manzini , Daniel Valenzuela

Bitmap indexes are frequently used to index multidimensional data. They rely mostly on sequential input/output. Bitmaps can be compressed to reduce input/output costs and minimize CPU usage. The most efficient compression techniques are…

Databases · Computer Science 2008-08-15 Kamel Aouiche , Daniel Lemire , Owen Kaser

The Burrows-Wheeler-Transform (BWT), a reversible string transformation, is one of the fundamental components of many current data structures in string processing. It is central in data compression, as well as in efficient query algorithms…

Data Structures and Algorithms · Computer Science 2024-04-16 Sara Giuliani , Shunsuke Inenaga , Zsuzsanna Lipták , Nicola Prezza , Marinella Sciortino , Anna Toffanello

Advances in DNA sequencing mean databases of thousands of human genomes will soon be commonplace. In this paper we introduce a simple technique for reducing the size of conventional indexes on such highly repetitive texts. Given upper…

Data Structures and Algorithms · Computer Science 2015-06-16 H. Ferrada , T. Gagie , T. Hirvola , S. J. Puglisi

We consider the problem of encoding a string of length $n$ from an integer alphabet of size $\sigma$ so that access and substring equality queries (that is, determining the equality of any two substrings) can be answered efficiently. Any…

Data Structures and Algorithms · Computer Science 2020-05-12 Nicola Prezza

We describe a data structure that stores a string $S$ in space similar to that of its Lempel-Ziv encoding and efficiently supports access, rank and select queries. These queries are fundamental for implementing succinct and compressed data…

Data Structures and Algorithms · Computer Science 2014-12-03 Djamal Belazzougui , Travis Gagie , Paweł Gawrychowski , Juha Kärkkäinen , Alberto Ordóñez , Simon J. Puglisi , Yasuo Tabei

Re-Pair is an efficient grammar compressor that operates by recursively replacing high-frequency character pairs with new grammar symbols. The most space-efficient linear-time algorithm computing Re-Pair uses $(1+\epsilon)n+\sqrt n$ words…

Data Structures and Algorithms · Computer Science 2017-04-28 Philip Bille , Inge Li Gørtz , Nicola Prezza

Sliced inverse regression (SIR) is a pioneer tool for supervised dimension reduction. It identifies the effective dimension reduction space, the subspace of significant factors with intrinsic lower dimensionality. In this paper, we propose…

Machine Learning · Statistics 2018-06-26 Ning Zhang , Zhou Yu , Qiang Wu

Retrieving documents and prepending them in-context at inference time improves performance of language model (LMs) on a wide range of tasks. However, these documents, often spanning hundreds of words, make inference substantially more…

Computation and Language · Computer Science 2023-10-09 Fangyuan Xu , Weijia Shi , Eunsol Choi

BERT based ranking models have achieved superior performance on various information retrieval tasks. However, the large number of parameters and complex self-attention operation come at a significant latency overhead. To remedy this, recent…

Information Retrieval · Computer Science 2021-10-06 Nachshon Cohen , Amit Portnoy , Besnik Fetahu , Amir Ingber

Compressive sensing claims that the sparse signals can be reconstructed exactly from many fewer measurements than traditionally believed necessary. One of issues ensuring the successful compressive sensing is to deal with the…

Information Theory · Computer Science 2009-03-31 Lianlin Li , Fang Li

In the theory of compressed sensing, restricted isometry analysis has become a standard tool for studying how efficiently a measurement matrix acquires information about sparse and compressible signals. Many recovery algorithms are known to…

Information Theory · Computer Science 2014-04-29 Holger Rauhut , Justin Romberg , Joel A. Tropp

The massive upload of text on the internet creates a huge inverted index in information retrieval systems, which hurts their efficiency. The purpose of this research is to measure the effect of the Multi-Layer Similarity model of the…

Information Retrieval · Computer Science 2020-04-29 Ahmad Hussein Ababneh , Joan Lu , Qiang Xu

Remote sensing (RS) images are usually stored in compressed format to reduce the storage size of the archives. Thus, existing content-based image retrieval (CBIR) systems in RS require decoding images before applying CBIR (which is…

Computer Vision and Pattern Recognition · Computer Science 2023-01-24 Gencer Sumbul , Jun Xiang , Nimisha Thekke Madam , Begüm Demir

The goal of grammar compression is to construct a small sized context free grammar which uniquely generates the input text data. Among grammar compression methods, RePair is known for its good practical compression performance. MR-RePair…

Data Structures and Algorithms · Computer Science 2019-10-31 Isamu Furuya

Self-supervised learning (SSL) has allowed substantial progress in Automatic Speech Recognition (ASR) performance in low-resource settings. In this context, it has been demonstrated that larger self-supervised feature extractors are crucial…

Audio and Speech Processing · Electrical Eng. & Systems 2023-03-14 Salah Zaiem , Robin Algayres , Titouan Parcollet , Slim Essid , Mirco Ravanelli