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Anomaly Detection in Audio With Concept Drift Using dynamic huffman coding

IEEE SENSORS JOURNAL 2022年第17期22卷 17126-17138页

作者： Kumari, Pratibha Saini, Mukesh Indian Inst Technol IIT Ropar Rupnagar 140001 India

When detecting anomalies in audio, it can often be necessary to consider concept drift: the distribution of the data may drift over time because of dynamically changing environments, and anomalies may become normal as time elapses. We propose to use dynamic huffman coding for anomaly detection in audio with concept drift. Compared with the existing method of adaptive Gaussian mixture modeling (AGMM), dynamic huffman coding does not require a priori information about the clusters and can adjust the number of clusters dynamically depending on the amount of variation in the audio. To control the size of the huffman tree, we propose to merge clusters that are close to each other instead of replacing rare clusters with new data. This reduces redundancy in the huffman tree while ensuring that it never forgets past information. On audio datasets with concept drift which we have curated ourselves, our proposed method achieves a higher area under the curve (AUC) compared with AGMM and fixed-length huffman trees.

关键词： Anomaly detection huffman coding Hidden Markov models Encoding Data models Adaptation models Sensors Anomaly detection concept drift unsupervised modelling dynamic huffman coding long term audio surveillance

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Design and hardware architectures for dynamic huffman coding

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IEE PROCEEDINGS-COMPUTERS AND DIGITAL TECHNIQUES 1995年第6期142卷 411-418页

作者： Liu, LY Wang, JF Wang, RJ Lee, JY Dept. of Electr. Eng. Nat. Cheng Kung Univ. Tainan Taiwan

To date, dynamic huffman coding has not been available for high-speed applications because the tree updating spends a lot of time by current adaptive huffman coding hardware, The authors present concurrent techniques and the parallel hardware architectures for dynamic huffman encoding and decoding. For step reduction, they employ the concurrent algorithm [15] for encoding as well as proposing the frequency presetting approach for decoding. For hardware architecture, they use the content addressable memory for performing the massive searching operations in parallel. The output rate achieved by the proposed encoding architecture is near 1 bit/cycle and the input rate of our decoding architecture is from 0.6 to near 1 bit/cycle. Compared with the fast design [5] which achieves the input/output rate of [log N]/[N + 1] bit/cycle for an N-symbol source on average, our architectures apparently have a higher throughput. Due to the improvement on the throughput, our dynamic coding architectures are able to serve for the applications with a higher speed demand.

关键词： dynamic huffman coding architecture algorithms

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Real-time lossless image compression by dynamic huffman coding hardware implementation

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JOURNAL OF REAL-TIME IMAGE PROCESSING 2024年第3期21卷 84-84页

作者： Lam, Duc Khai Univ Informat Technol Ho Chi Minh City Vietnam Vietnam Natl Univ Ho Chi Minh City Vietnam

Over the decades, implementing information technology (IT) has become increasingly common, equating to an increasing amount of data that needs to be stored, creating a massive challenge in data storage. Using a large storage capacity can solve the problem of the file size. However, this method is costly in terms of both capacity and bandwidth. One possible method is data compression, which significantly reduces the file size. With the development of IT and increasing computing capacity, data compression is becoming more and more widespread in many fields, such as broadcast television, aircraft, computer transmission, and medical imaging. In this work, we introduce an image compression algorithm based on the huffman coding algorithm and use linear techniques to increase image compression efficiency. Besides, we replace 8-bit pixel-by-pixel compression by dividing one pixel into two 4-bit halves to save hardware capacity (because only 4-bit for each input) and optimize run time (because the number of different inputs is less). The goal is to reduce the image's complexity, increase the data's repetition rate, reduce the compression time, and increase the image compression efficiency. A hardware accelerator is designed and implemented on the Virtex-7 VC707 FPGA to make it work in real-time. The achieved average compression ratio is 3,467. Hardware design achieves a maximum frequency of 125 MHz.

关键词： dynamic huffman coding Linear prediction Real time FPGA

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Remark on "Algorithm 673: dynamic huffman coding"

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ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE 2016年第1期42卷 1页

作者： Novoselsky, Alexander Kagan, Eugene Weizmann Inst Sci 234 Herzl Str IL-76100 Rehovot Israel Ariel Univ IL-40700 Ariel Israel

This remark presents a correction to Algorithm 673 (dynamic huffman coding) [Vitter 1989] and its translation to MATLAB.

关键词： Algorithms dynamic huffman coding

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Image and Text Compression Using dynamic huffman and RLE coding

Image and Text Compression Using Dynamic Huffman and RLE Cod...

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International Conference on Soft Computing for Problem Solving (SocProS 2011)

作者： Patil, Rupali B. Kulat, K. D. Visvesvaraya Natl Inst Technol Elect & Commun Dept Nagpur Maharashtra India

ISBN: (纸本)9788132204909

This Paper considers the design of lossless image and data compression methods dedicated to still images and text data. For Images, after a preprocessing step (RGB to gray transformation, resizing) and for text after a preprocessing step (ASCII conversion), dynamic huffman and Run Length Encoding (RLE) is applied. The dynamic huffman coding involves computing an approximation to the probabilities of occurrence "on the fly", as the ensemble is being transmitted with the aim to obtain the best possible compression ratio CR and Time Elapsed to compress. The additional parameters of evaluation in case of images are PSNR and MSE. The efficiency of the proposed methods is verified by applying these techniques to variety of data and images. Motivation behind this work is to provide a detail analysis of lossless compression methods which can be best suited in cognitive radio environment.

关键词： Lossless compression Data compression dynamic huffman coding Time Elapsed Run length Encoding

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huffman coding of DCT coefficients using dynamic codeword assignment and adaptive codebook selection

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1998年第3期12卷 253-262页

作者： Jeon, B Park, J Jeong, J Sungkyunkwan Univ Sch ECE Suwon South Korea Samsung Elect Co Signal Proc Lab Suwon South Korea Hanyang Univ Dept Elect Commun Engn Seoul 133791 South Korea

In many image sequence compression applications, huffman coding is used to eliminate statistical redundancy resident in given data. The huffman table is often pre-defined to reduce coding delay and table transmission overhead. Local symbol statistics, however, may be much different from the global ones manifested in the pre-defined table. In this paper, we propose three huffman coding methods in which pre-defined codebooks are effectively manipulated according to local symbol statistics. The first proposed method dynamically modifies the symbol-codeword association without rebuilding the huffman tree itself. The encoder and decoder maintain identical symbol-codeword association by performing the same modifications to the huffman table, thus eliminating extra transmission overhead. The second method adaptively selects a codebook from a set of given ones, which produces the minimum number of bits. The transmission overhead in this method is the codebook selection information, which is observed to be negligible compared with the bit saving attained. Finally, we combine the two aforementioned methods to further improve compression efficiency. Experiments are carried out using five test image sequences to demonstrate the compression performance of the proposed methods. (C) 1998 Elsevier Science B.V. All rights reserved.

关键词： huffman coding dynamic huffman coding re-association compression

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Forward Looking huffman coding

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THEORY OF COMPUTING SYSTEMS 2021年第3期65卷 593-612页

作者： Klein, Shmuel T. Saadia, Shoham Shapira, Dana Bar Ilan Univ Dept Comp Sci IL-52900 Ramat Gan Israel Ariel Univ Dept Comp Sci IL-40700 Ariel Israel

huffman coding is known to be optimal, yet its dynamic version may yield smaller compressed files. The best known bound is that the number of bits used by dynamic huffman coding in order to encode a message ofncharacters is at most larger bynbits than the size of the file required by static huffman coding. In particular, dynamic huffman coding can also generate a larger encoded file than the static variant, though in practice the file might sometimes be smaller. We propose here a new variant of huffman encoding, that provably always performs better than static huffman coding by at leastm- 1 bits, wheremdenotes the size of the alphabet, and may be better than the standard dynamic huffman coding for certain files. The algorithm is based on reversing the direction for the references of the encoded elements, from pointing backwards into the past to looking forward into the future.

关键词： Lossless data compression huffman coding dynamic huffman coding

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IoT Sensor Data Stream Compression with Hybrid Compression Algorithms 15

IoT Sensor Data Stream Compression with Hybrid Compression A...

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15th International Conference on Computing Communication and Networking Technologies, ICCCNT 2024

作者： Garikipati, Karthik Muppala, Tejaswi Vinitha Chowdary, A. Sahay, Apurvanand Amrita School of Computing Amrita Vishwa Vidyapeetham Department of Computer Science and Engineering Bengaluru India

ISBN: (纸本)9798350370249

The recent world advancement in technology especially in the use of IoT devices has posed some serious complications in terms of how effectively we can convey data, this is normally a result of the limited bandwidth and power capacity. In this paper, we look into the need for efficient data compression in IoT devices and come up with a new approach to compress the data stream needed for IoT sensors. In this paper, we propose to integrate dynamic huffman coding with Run Length Encoding smoothly as one novel network coding strategy to decrease the load carried by the communication channels and at the same time ensure the originality of the transmitted data. The proposed method is based on the use of RLE to remove a lot of redundant data and dynamic huffman coding for further data compression. When compared with other central algorithms like dynamic huffman, static huffman, RLE, LZW, ZLIB, LZMA, and BZ2 this hybrid approach provided more efficient compression ratios and consumed less power. Compression can be considered an essential paradigm for IoT devices because it can minimize the restrictions associated with the prevention of limited bandwidths and power sources that are characteristic of such devices, which results in improved data sending and a longer lifespan of devices. As substantiated by the findings from our experiments, this approach holds a high degree of effectiveness and, therefore, is suitable for the IoT domain with a scarcity of resources in particular. The contributions of this research support the promotion of compression strategies while considering the IoT-specific needs thus enhancing standard system outcomes and durability. © 2024 IEEE.

关键词： Bandwidth Constraints BZ2 Data Compression dynamic huffman coding Hybrid Techniques Internet of Things (IoT) IoT Sensors LZMA LZW Power Constraints RLE Run-Length Encoding Static huffman coding ZLIB

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