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Browsing by Subject "lossless compression"

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    Item type:Article, Access status: Open Access ,
    Optimized lossless audio compression using DCT energy thresholding and machine learning technique
    (Wydawnictwa AGH, 2025) Debnath, Asish; Mondal, Uttam Kr.
    This paper proposes a novel lossless audio compression technique, utilizing the Discrete Cosine Transform (DCT) coefficient-controlled technique based on energy thresholding, an XOR-based neural network compression model, and a CNN model. Initially, the DCT is applied to the input audio signal to achieve better energy compaction, followed by transforming selected DCT coefficients into a compressed binary stream. Subsequently, this binary stream is passed to two prediction-based optimized models: an XOR model and a CNN model for further compression.The binary stream is divided into two equal pieces, the data and the key. The XOR neural network model processes the data and key to produce an compressed XORed binary stream. Using a proposed CNN architecture, this stream is further compressed with latent space representations to produce compressed audio data. The simulation findings are analyzed using various statistical and robustness measures and compared with existing approaches.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Web log compression
    (Wydawnictwa AGH, 2007) Grabowski, Szymon; Deorowicz, Sebastian
    Web log data store client activity on a particular server, usually in form of one-line »hits« with information like the client's IP, date/ time, requested file or query, download size in bytes etc. Web logs of popular sites may grow at the pace of hundreds of megabytes a day, or even more. It makes sense to archive old logs, to analyze them further, e.g. for detecting attacks or other server abuse patterns. In this work we present a specialized lossless Apache web log preprocessor and test it with combination of several popular general-purpose compressors. The test results show the proposed transform improves the compression efficiency of general-purpose compressors on average by 65% in case of gzip and 52% in case of bzip2.