English
Related papers

Related papers: LZ78 Substring Compression in Compressed Space

200 papers

As nowadays Machine Learning (ML) techniques are generating huge data collections, the problem of how to efficiently engineer their storage and operations is becoming of paramount importance. In this article we propose a new lossless…

Data Structures and Algorithms · Computer Science 2022-03-31 Paolo Ferragina , Travis Gagie , Dominik Köppl , Giovanni Manzini , Gonzalo Navarro , Manuel Striani , Francesco Tosoni

This paper investigates the size in bits of the LZ77 encoding, which is the most popular and efficient variant of the Lempel-Ziv encodings used in data compression. We prove that, for a wide natural class of variable-length encoders for…

Discrete Mathematics · Computer Science 2018-01-10 Dmitry Kosolobov

We present a framework facilitating the implementation and comparison of text compression algorithms. We evaluate its features by a case study on two novel compression algorithms based on the Lempel-Ziv compression schemes that perform well…

Data Structures and Algorithms · Computer Science 2021-04-23 Patrick Dinklage , Johannes Fischer , Dominik Köppl , Marvin Löbel , Kunihiko Sadakane

Data compression is very important feature in terms of saving the memory space. In this proposal, an indexed dictionary based compression is used for text data, where the word's reference in dictionary is used for compression. This approach…

Other Computer Science · Computer Science 2015-12-23 Vivek Dimri , Prof. Ranjit Biswas

Many large-scale Web applications that require ranked top-k retrieval such as Web search and online advertising are implemented using inverted indices. An inverted index represents a sparse term-document matrix, where non-zero elements…

Information Retrieval · Computer Science 2015-03-19 George Beskales , Marcus Fontoura , Maxim Gurevich , Sergei Vassilvitskii , Vanja Josifovski

Sequence model based NLP applications can be large. Yet, many applications that benefit from them run on small devices with very limited compute and storage capabilities, while still having run-time constraints. As a result, there is a need…

Computation and Language · Computer Science 2020-10-08 Urmish Thakker , Jesse Beu , Dibakar Gope , Ganesh Dasika , Matthew Mattina

In this paper, we introduce a novel approach for systematically solving dataset condensation problem in an efficient manner by exploiting the regularity in a given dataset. Instead of condensing the dataset directly in the original input…

Machine Learning · Computer Science 2022-08-24 Hae Beom Lee , Dong Bok Lee , Sung Ju Hwang

In this paper, we show that the LZ77 factorization of a text T {\in\Sigma^n} can be computed in O(R log n) bits of working space and O(n log R) time, R being the number of runs in the Burrows-Wheeler transform of T reversed. For extremely…

Data Structures and Algorithms · Computer Science 2015-10-22 Nicola Prezza , Alberto Policriti

We present RCT, a new compact data structure to represent trajectories of objects. It is based on a relative compression technique called Relative Lempel-Ziv (RLZ), which compresses sequences by applying an LZ77 encoding with respect to an…

Data Structures and Algorithms · Computer Science 2018-10-16 Nieves R. Brisaboa , Travis Gagie , Adrián Gómez-Brandón , Gonzalo Navarro , José R. Paramá

We investigate two closely related LZ78-based compression schemes: LZMW (an old scheme by Miller and Wegman) and LZD (a recent variant by Goto et al.). Both LZD and LZMW naturally produce a grammar for a string of length $n$; we show that…

Data Structures and Algorithms · Computer Science 2017-07-26 Golnaz Badkobeh , Travis Gagie , Shunsuke Inenaga , Tomasz Kociumaka , Dmitry Kosolobov , Simon J. Puglisi

We propose a novel, lightweight supervised dictionary learning framework for text classification based on data compression and representation. This two-phase algorithm initially employs the Lempel-Ziv-Welch (LZW) algorithm to construct a…

Computation and Language · Computer Science 2024-05-06 Li Wan , Tansu Alpcan , Margreta Kuijper , Emanuele Viterbo

This paper presents an algorithm for the modification of data compressed using LZ-End, a derivate of LZ77, without prior decompression. The performance of the algorithm and the impact of the modifications on the compression ratio is…

Data Structures and Algorithms · Computer Science 2020-07-14 Daniel Roodt , Ulrich Speidel , Vimal Kumar , Ryan K. L. Ko

Data compression is a powerful tool for managing massive but repetitive datasets, especially schemes such as grammar-based compression that support computation over the data without decompressing it. In the best case such a scheme takes a…

Data Structures and Algorithms · Computer Science 2019-06-04 Travis Gagie , Tomohiro I , Giovanni Manzini , Gonzalo Navarro , Hiroshi Sakamoto , Yoshimasa Takabatake

Deep learning models have become state of the art for natural language processing (NLP) tasks, however deploying these models in production system poses significant memory constraints. Existing compression methods are either lossy or…

Machine Learning · Computer Science 2018-11-05 Anish Acharya , Rahul Goel , Angeliki Metallinou , Inderjit Dhillon

The unrestricted LZ78 universal data-compression algorithm (as well as the LZ77 and LZW versions) achieves asymptotically, as the block-length tends to infinity, the FS compressibility, namely the best compression-ratio that may be achieved…

Information Theory · Computer Science 2015-03-16 Jacob Ziv

Low-rank matrix factorization (MF) is an important technique in data science. The key idea of MF is that there exists latent structures in the data, by uncovering which we could obtain a compressed representation of the data. By factorizing…

Numerical Analysis · Computer Science 2016-05-09 Yuan Lu , Jie Yang

Indexing highly repetitive collections has become a relevant problem with the emergence of large repositories of versioned documents, among other applications. These collections may reach huge sizes, but are formed mostly of documents that…

Information Retrieval · Computer Science 2016-05-25 Francisco Claude , Antonio Fariña , Miguel A. Martínez-Prieto , Gonzalo Navarro

Recent transformer language models achieve outstanding results in many natural language processing (NLP) tasks. However, their enormous size often makes them impractical on memory-constrained devices, requiring practitioners to compress…

Computation and Language · Computer Science 2023-02-09 Mohammadreza Banaei , Klaudia Bałazy , Artur Kasymov , Rémi Lebret , Jacek Tabor , Karl Aberer

This paper presents conditional versions of Lempel-Ziv (LZ) algorithm for settings where compressor and decompressor have access to the same side information. We propose a fixed-length-parsing LZ algorithm with side information, motivated…

Information Theory · Computer Science 2017-07-19 Yeohee Im , Sergio Verdú

We consider the problem of decompressing the Lempel--Ziv 77 representation of a string $S$ of length $n$ using a working space as close as possible to the size $z$ of the input. The folklore solution for the problem runs in $O(n)$ time but…

Data Structures and Algorithms · Computer Science 2019-11-05 Philip Bille , Mikko Berggren Ettienne , Travis Gagie , Inge Li Gørtz , Nicola Prezza