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作者： Klejmová, Eva Brno University of Technology

Bakalářská práce se zabývá popisem základních vlastností současných komprimačních algoritmů využívaných pro komprimaci videa ve vysokém rozlišení. ... 详细信息

Bakalářská práce se zabývá popisem základních vlastností současných komprimačních algoritmů využívaných pro komprimaci videa ve vysokém rozlišení. Práce se zaměřuje hlavně na rozdíly mezi jednotlivými algoritmy a jejich celkovou funkcionalitu. Navrhuje postupy pro komprimaci videosekvencí s využitím referenčních implementací vybraných kodeků, včetně popisu vybraných parametrů. Součástí práce je srovnání objektivní a subjektivní kvality komprimovaných videosekvencí, a také časová náročnost jednotlivých implementací. Dále je navržena grafická nadstavba usnadňující použití jednotlivých kodeků.

关键词： Komprimační algoritmus komprese videa HD video H.265 VC-1 VP8 kvalita obrazu kvalita videa PSNR SSIM compression algorithm video compression HD video H.265 VC-1 VP8 picture quality video quality PSNR SSIM Text

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Huffman-based lossless image encoding scheme

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JOURNAL OF ELECTRONIC IMAGING 2021年第5期30卷 053004-053004页

作者： Erdal, Erdal Kirikkale Univ Dept Comp Engn Fac Engn & Architecture Kirikkale Turkey

The data produced in today's Internet and computer world are expanding their wings day by day. With the passage of time, storage and archiving of this data are becoming a significant problem. To overcome this problem, attempts have been made to reduce data sizes using compression methods. Therefore, compression algorithms have received great attention. In this study, two efficient encoding algorithms are presented and explained in a crystal-clear manner. In all compression algorithms, frequency modulation is used. In this way, the characters with the highest frequency after each character are determined and the Huffman encoding algorithm is applied to them. In this study, the compression ratio (CR) is 49.44%. Moreover, 30 randomly selected images in three different datasets consisting of USC-SIPI, UCID, and STARE databases have been used to evaluate the performance of the algorithms. Consequently, excellent results have been obtained in all test images according to well-known comparison algorithms such as the Huffman encoding algorithm, arithmetic coding algorithm, and LPHEA. (C) 2021 SPIE and IS&T

关键词： image compression encoding scheme Huffman encoding algorithm compression algorithm lossless compression

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Design and Implementation of Modified DDS Based on FPGA

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Procedia Computer Science 2018年 131卷 261-266页

作者： Pu Wang Yuming Zhang Jun Yang School of Information Science and Engineering Yunnan university KunMing 650091 China

Frequency synthesizer is known as the "heart" of electronic systems, direct digital frequency synthesizer (DDS) relative to the first two generation of frequency synthesis technology has obvious advantages, but also existing traditional structure of the DDS output stray too, shortage of output frequency is limited. Aiming at these two problems, the overall structure of DDS is improved by compression algorithm, phase jitter and balanced DAC structure. The parallel phase accumulator is designed with parallel and flow technology, and the output frequency of the system is improved. At the same time, using the FPGA technology, the various modules were implemented by Verilog HDL language design, and finally the modified DDS model was completed based on FPGA design.

关键词： DDS FPGA compression algorithm Phase jitter method Balanced DAC structure

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A Study of Cantilever Beam Vibration Wireless Transmission System

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Procedia Engineering 2011年 14卷 1300-1306页

作者： Guangxiang Yang WenHui Duan Hua Liang School of Computer Science and Information Engineering Chongqing Technology and Business University Chongqing China Faculty of Mechanical Engineering Monash University Australia

ZigBee is a wireless communication technology which based on IEEE 802.15.4 protocol, communicating within short distance and with low power. ZigBee is applied in cantilever beam vibration measurement system in this paper, and the old wired transmission system are substituted by IEEE 802.15.4, software and sensor circuit are designed, reliable data transmission method and half byte compression algorithm are analyzed, and also provide basis and data analyzing solution for dynamics model of cantilever beam which using piezoelectric transducer. Experimental results show that with wireless ZigBee transmission solution and compression algorithm, the acquisition data of 150 bytes per second can be achieved, which will improve the quality of vibration analysis.

关键词： ZigBee Piezoelectric Transducer compression algorithm Cantilever Beam

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Stress-associated scattering attenuation and intrinsic attenuation from ultrasonic measurements

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ASEG Extended Abstracts 2015年第1期2015卷 1-4页

Acoustic attenuation has been proved to be an indicator of stress changes in solid structures. Acoustic coda, as a superposition of incoherent scattered waves, reflects small-scale random heterogeneities in solids. Acoustic coda attenuation, as a combination of intrinsic attenuation and scattering attenuation, contains information on stress changes as a result of changes in the physical state of small-scale heterogeneous structures. Based on the ultrasonic measurements of a rock sample with intra-grain pores and fractures under different pore-pressure induced effective stresses, we compute the stress-associated coda attenuation quality factorsQPCandQSCas a function of frequencies. Based on the digital heterogeneous cores of the sample, the experimental results are validated and corrected with numerical results by the finite-difference simulation of Biot’s poroelastic equations and the Monte Carlo simulation of multiple scatterings, respectively. The quality factors characterize its scale dependence of scattering attenuation on stress variations in rocks. We compare them with the intrinsic attenuation quality factorsQPandQScalculated by the spectral ratio method and BISQ model, respectively, from ultrasonic measurements. Comparisons demonstrate that the scattering attenuation is much stronger, particularly when ultrasonic wavelengths are comparable to the scale of pores and grains. The intrinsic and coda attenuations versus increasing effective stresses present quite different nonlinear features, whereQPCandQSCshow a greater sensitivity to pore pressure thanQPand QS.

关键词： reverse time migration data storage Nyquist theorem compression algorithm finite-difference

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H-Matrix Accelerated Solution of Surface-Volume-Surface EFIE for Fast Electromagnetic Analysis on 3-D Composite Dielectric Objects

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IEEE JOURNAL ON MULTISCALE AND MULTIPHYSICS COMPUTATIONAL TECHNIQUES 2019年 4卷 152-162页

作者： Gholami, Reza Menshov, Anton Okhmatovski, Vladimir, I Univ Manitoba Dept Elect & Comp Engn Winnipeg MB R3T 5V6 Canada Univ Texas Austin Dept Elect & Comp Engn Austin TX 78712 USA

An efficient fast direct algorithm based on the hierarchical (H) matrices is presented for solution of the radiation problems on piecewise homogeneous dielectric objects using Method of Moment (MoM) discretization of the surface-volume-surface electric field integral equation (SVS-EFIE). The SVS-EFIE for the composite objects introduces independent surface electric current density on the boundary of each region. Therefore, different from the traditional Poggio-Miller-Chang-Harrington-Wu-Tsai formulation, in the SVS-EFIE, the object regions can be meshing independently according to their local properties which improves the flexibility and efficiency of the proposed method. It also makes the proposed algorithms appropriate for the analysis of both multiscale and large-scale composite structures. The numerical results from the proposed fast method are provided for the high-loss biological tissues from bioelectromagnetics applications and agree well with the analytical Mie series solution and commercial software. The CPU time and memory cost of the required H-matrix operations are analyzed in details and verified through several numerical experiments. The new computational framework allows for fast direct solution of 3-D radiation and scattering problems of moderate electrical size with O(P-alpha log(2) P) CPU time and O(P-alpha log P) memory complexity, P being the number of surface unknowns produced by the MoM discretization, and 1 <= alpha <= 1.5 being a geometry-dependent parameter.

关键词： compression algorithm electromagnetic analysis fast solvers integral equations (IE) method of moments (MoM) multiscale

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IMPLEMENTATION OF AN EVENT-TRIGGERED SMART SENSOR NETWORK ARCHITECTURE BASED ON THE IEEE 802.15.4 STANDARD

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IFAC Proceedings Volumes 2007年第22期40卷 279-284页

作者： Erico Meneses Leão Luiz Affonso Guedes Francisco Vasques Department of Computer Engineering and Automation - UFRN - Natal - Brazil Department of Mechanical Engineering - University of Porto - Porto - Portugal

A smart transducer is the integration of a sensor/actuator element, a processing unit, and a network interface. Smart sensor networks are composed of smart transducer nodes interconnected through a communication network. This paper presents an event driven smart sensor network architecture (asynchronous data) and its respective implementation based in the IEEE 802.15.4 standard. The events are derived from a data compression algorithm embedded into the smart sensor, which compresses data from the sensor. The architecture also supports configuration and monitoring activities for the over all distributed system.

关键词： smart sensor network architecture events IEEE 802.15.4 compression algorithm

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Reducing data storage in reverse time migration

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ASEG Extended Abstracts 2015年第1期2015卷 1-4页

Prestack reverse time migration (RTM) requires extensive data storage since it computes wavefields in forward time and accesses wavefields in reverse order. We first review several successful schemes that have been proposed to reduce data storage, but require more computational redundancies. We propose two effective strategies to reduce data storage during RTM. The first strategy is based on the Nyquist sampling theorem, which involves no extra computational cost. The fact is that the time sampling intervals required by numerical algorithms or given by field records is generally several times smaller than that satisfied by the Nyquist sampling theorem. Therefore, we can correlate the source wavefields with the receiver wavefields at the Nyquist time step, which helps decrease storage of time history. The second strategy is based on a lossless compression algorithm, which is widely used in computer science and information theory. The compression approach reduces storage significantly at a little computational cost. Numerical examples show that the two proposed strategies are effective and efficient.

关键词： reverse time migration data storage Nyquist theorem compression algorithm finite-difference

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Real-Time Image Transmission algorithm in WSN with Limited Bandwidth

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INTERNATIONAL JOURNAL OF ONLINE ENGINEERING 2018年第12期14卷 57-71页

作者： Huang, Hui Li, Zhe Hubei Engn Univ Coll Technol Xiaogan 432000 Peoples R China Hubei Engn Univ Sch Econ & Management Xiaogan 432000 Peoples R China

In this paper, a real-time image transmission algorithm in WSN with limited bandwidth networks is studied. Firstly, a simple and effective monitoring network architecture is established, which allows multiple video monitoring nodes to access the network, and the data transmission is controlled by the synchronization mechanism without collision. Then, the image data is compressed locally at the monitoring nodes (over 85%), so that the image of each node can meet the needs of real-time data transmission, and the overall power consumption of the system is greatly reduced. Finally, based on NVIDIA TX1, four test nodes are constructed to test the algorithm cumulatively, which verifies the effectiveness of the system framework and compression algorithm.

关键词： limited bandwidth networks real-time image transmission compression algorithm synchronous network architecture NVIDIA TX1

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A delayed input DFA optimized algorithm of bounding default path

A delayed input DFA optimized algorithm of bounding default ...

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2011 IEEE International Conference on Computer Science and Automation Engineering(CSAE 2011)

作者： Jin Qu, Rongcai Zhao, Peng Liu, Zishuang Li National Digital Switching System Engineering and Technological Research Center Zhengzhou, Henan, China Qin Li Zheng Zhou Light Industry Vocational College, Zhengzhou, Henan, China

To improve the storage space of finite automata on regular expression matching, the paper researches the main idea of the delayed input DFA algorithm based on bounding default path, and analyses the algorithm problem when bounding small length default path. Then we propose optimized algorithm based on weight first principle and node first principle and assess them on the actual rule set, the results show that the optimized algorithm could effectively improve the compression ratio when the default path is bounded small.

关键词： Deterministic Finite Automaton (DFA) Deep Packet Inspection (DPI) Regular Expression Default Path compression algorithm

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