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IEEE Symposium on Reliable Distributed Systems Workshops (SRDSW)

作者： Kousuke Ota Viet Ta Hong Haruhiko Kaneko Graduate School of Information Science and Engineering Tokyo Institute of Technology Tokyo Japan

Erasure correction coding is an effective technique to improve the dependability of distributed storage systems and disk arrays, in which codeword symbols are distributed over multiple storage elements (SEs), e.g., storage nodes and disk drives. One of the major drawbacks of such storage systems is increased data update cost, that is, data update in one SE induces simultaneous multiple update accesses to a specified set of SEs to keep consistency of codewords. The SEs sometimes have high access cost due to, for example, large delay caused by access collision with other workloads, temporary network cutoff, and malicious attack, and high energy consumption caused by resume operations from power suspension mode. This paper proposes an adaptive coding and data allocation method which can reduce the number of update accesses to SEs having high access cost. The proposed method is based on adaptive allocation of codeword symbols of Reed-Solomon code with conditional overwrites of check symbols, and also on background relocation of codeword symbols. Preliminary simulation results show that the proposed method provides sufficiently low data loss probability with reduced energy consumption compared to RAID-1 and -6.

关键词： Encoding Arrays Resource management adaptive arrays Energy consumption adaptive coding Barium

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Correction to “An Efficient adaptive Binary Arithmetic Coder Based on Logarithmic Domain” [Nov 15 4225-4239]

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IEEE Transactions on Image Processing 2016年第3期25卷 1260-1260页

作者： Quanhe Yu Wei Yu Ping Yang Jianhua Zheng Xiaozhen Zheng Yun He Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing China HiSilicon Technologies Company Ltd. Beijing China

For the above-named work, a missing sentence that should have been included in the first footnote is provided.

关键词： Binary codes Data compression Video codes adaptive coding

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Efficient Lossless coding of Highpass Bands from Block-based Motion Compensated Wavelet Lifting Using JPEG 2000

Efficient Lossless Coding of Highpass Bands from Block-based...

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IEEE Visual Communications and Image Processing Conference

作者： Schnurrer, Wolfgang Troeger, Tobias Richter, Thomas Seiler, Juergen Kaup, Andre Univ Erlangen Nurnberg Multimedia Commun & Signal Proc Cauerstr 7 D-91058 Erlangen Germany

ISBN: (纸本)9781479961399

Lossless image coding is a crucial task especially in the medical area, e.g., for volumes from Computed Tomography or Magnetic Resonance Tomography. Besides lossless coding, compensated wavelet lifting offers a scalable representation of such huge volumes. While compensation methods increase the details in the lowpass band, they also vary the characteristics of the wavelet coefficients, so an adaption of the coefficient coder should be considered. We propose a simple invertible extension for JPEG 2000 that can reduce the filesize for lossless coding of the highpass band by 0.8% on average with peak rate saving of 1.1%.

关键词： Computed Tomography Wavelet Lifting Signal Analysis adaptive coding Lossless Image coding

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Down-sampling Based Embedded Compression in Video Systems

Down-sampling Based Embedded Compression in Video Systems

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IEEE International Symposium on Circuits and Systems

作者： Yuxiang Shen Xiaolin Wu Department of Electrical and Computer Engineering McMaster University

ISBN: (纸本)9781479983926

With rapid increase of image resolution in modern video processing and display systems, the bandwidth and power consumption of external memory are becoming serious bottlenecks. This problem can be alleviated by high-fidelity embedded compression (EC) techniques for video frame buffers. Classic lossless or near-lossless coding methods like CALIC are ill suited for embedded systems due to their high complexity. In this work, a new, simple infra-frame EC technique based on downsampling and side-information aided upsampling is developed. Through a study of a family of downsampling schemes, an optimal one is found and analyzed for EC. This downsampling scheme gives birth to the new EC technique. The main idea is to first split an image into blocks, and then adaptively choose different down sampling patterns and upsampling methods to code/decode these blocks. For a memory bandwidth reduction of 60%, the proposed EC system can achieve PSNR above 40dB, while allowing very simple, low-cost real-time hardware realization. A noteworthy novelty of this work is compression without entropy coding. The resulting code stream is of fixed-rate, supporting random access to pixel blocks.

关键词： embedded compression downsampling pattern adaptive coding

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Improved opportunistic feedback with multiuser diversity for wireless systems with finite queue

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IET COMMUNICATIONS 2014年第6期8卷 852-859页

作者： Li, Hang Guo, Qinghua Huang, Defeng David Univ Western Australia Sch Elect Elect & Comp Engn Perth WA 6009 Australia Univ Wollongong Sch Elect Comp & Telecommun Engn Wollongong NSW 2522 Australia

A contention-based opportunistic feedback protocol has been proposed in the literature, to achieve multiuser diversity for the downlink transmission of a multiuser wireless system, with the assumption that the incoming data for the active users are infinitely backlogged. However, this assumption is not valid if the authors consider the finite-length queuing effect in practical systems. By taking not only the channel states, but also the queuing states into account, the authors propose an improved opportunistic feedback protocol with multiuser diversity, and analyse its performance with adaptive modulation and coding. Additionally, instead of solving a system of equations directly, a simple iterative method is proposed to obtain the stationary distribution of the system, where the system behaviour is modelled by a two-dimensional finite-state Markov chain. Numerical results demonstrate that the authors proposed protocol is superior to the protocol in the literature in terms of the average throughput, the average spectral efficiency and the average packet delay, when considering the queuing dynamics.

关键词： adaptive codes adaptive modulation iterative methods Markov processes multiuser channels packet radio networks protocols queueing theory average packet delay average spectral efficiency two dimensional finite state Markov chain stationary distribution iterative method adaptive coding adaptive modulation finite length queuing effect multiuser wireless system downlink transmission contention-based opportunistic feedback protocol finite queue multiuser diversity improved opportunistic feedback

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adaptive erasure code based distributed storage systems

Adaptive erasure code based distributed storage systems

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Canadian Workshop on Information Theory (CWIT)

作者： Brijesh Kumar Rai Department of Electronics and Electrical Engineering Indian Institute of Technology Guwahati Guwahati Assam

Consider the following scenario: A data storage service provider provides an erasure code based distributed storage system (DSS). For the same data, the service provider gives several options: an (n i , k i ) erasure code based DSS for i = 1,2, ..., m. The service provider charges differently for different options (say dollar Pi for an (n i , k i ) erasure code based DSS for the data B of size |B|). A client had initially chosen for an (n i , k i ) erasure code based DSS. At some point of time, the client wants to change for another option, say for an (n j , k j ) erasure code based DSS for the same data, where 1≤ i, j ≤ m, i ≠ j. Thus, service provider would require to convert the (n i , k i ) erasure code based DSS into an (n j , k j ) erasure code based DSS. The service provider has the following problem: How to design an erasure code based DSS so that the conversion of an (n i , k i ) erasure code based DSS into an (n j , k j ) erasure code based DSS, for 1 ≤ i, j ≤ m, i ≠ j, can be done by downloading the minimum amount of data? In this paper, we present an adaptive coding scheme which requires to download the minimum amount of data while converting an (n i , k i ) erasure code based DSS to an (n j , k j ) erasure code based DSS, where 1 ≤ i, j ≤ m, i ≠ j.

关键词： Decision support systems Maintenance engineering Encoding Spread spectrum communication Conferences adaptive coding

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An Energy-Efficient Solution for Packet-Based Transmissions with QoS Constraints in the Multibeam Satellite Downlink 7

An Energy-Efficient Solution for Packet-Based Transmissions ...

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7th Advanced Satellite Multimedia Systems Conference / 13th Signal Processing for Space Communications Workshop (ASMS/SPSC)

作者： Andreotti, Riccardo Giannetti, Filippo Luise, Marco Univ Pisa Dept Informat Engn I-56100 Pisa Italy

ISBN: (纸本)9781479958931

This paper tackles the issue of boosting the capacity of xDSL networks in the presence of geographical gaps. An effective approach for such a kind of operating scenarios consists in exploiting the downlink of either legacy broadcast or advanced multibeam satellites for the delivering of packed-based traffic. This can be done by resorting to the data link layer protocol named Generic Stream Encapsulation which enables the transport of IP traffic (or any other packet oriented protocol) over the DVB-S2 uni-directional physical layer link. The solution presented in this paper consists first in the derivation of an adaptive coding and modulation (ACM) scheme for such an IP over DVB-S2 system, aimed at maximizing the "goodput" (GP), i.e., the offered layer-3 data rate, net of encapsulation overhead. To this aim, the look-up table for ACM is numerically derived by associating to any signal-to-noise-plus-interference ratio of the satellite downlink, the pair "modulation order/coding rate" yielding the highest value of GP. Then, in case of multibeam coverage, in order to manage the co-channel interference arising from beams exploiting the same band, an adaptive power control is also proposed. The goal of the latter is to maximize the energy-efficiency of the downlink satellite transmission while guaranteeing a given quality-of-service over each link in terms of minimum-GP constraint.

关键词： Digital video broadcasting Downlink Encoding Modulation Quality of service Satellite broadcasting Satellites Downlink satellites Satellite broadcasting Quality of service digital video broadcasting Energy efficiency adaptive power control DVB-S2 adaptive coding

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A Video coding Scheme with adaptive Intra-frame Selection

A Video Coding Scheme with Adaptive Intra-frame Selection

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International Conference on Computer Sciences and Applications (CSA)

作者： Guo, Tianhao Guo, Dabo Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Peoples R China Shanxi Univ Coll Phys & Elect Engn Taiyuan 030006 Peoples R China

ISBN: (纸本)9780769551258

Intra-frame coding costs much more bits than inter-frame coding in a video encoder. The Assignment of the intra-frames is independent of video contents in current CODEC. This work proposes an adaptive Delaunay triangular mesh (DTM) based motion estimation/motion compensation (ME/MC) and DCT hybrid coding scheme with an ability to perceive the change of the content of any videos and assign the intra-frame in the moment with an abrupt change in contents of picture, e.g. an occlude object (objects) entering picture. This mechanism improves coding efficiencies. Scene-adaptive DTM generation algorithm is firstly present. Moreover, two-stage successive nodal tracking, which guarantees correct correspondence searching and prohibits the degeneration of the meshes, is then proposed. Furthermore, a steepest descent algorithm is derived in detail in effort to speed up the optimization process. Finally, a framework of the coding scheme and a brief description of the implementation methods are present. The experiment results demonstrate the adaptive intra frame refresh and other benefits in compression efficiency.

关键词： video coding Delaunay triangulation adaptive coding

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A Practical Approach to adaptive coding for the Three-Node Relay Channel

A Practical Approach to Adaptive Coding for the Three-Node R...

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IEEE Conference on Wireless Communications and Networking

作者： Zhongwei Si Ragnar Thobaben Mikael Skoglund ACCESS Linnaeus Center School of Electrical Engineering Royal Institute of Technology Stockholm Sweden

In this paper we propose a new adaptive coding scheme for distributed channel coding for the three-node relay channel. In order to make it feasible for application in wireless sensor networks, the distributed code is built from standard components like Turbo and convolutional codes, and adaptation at the relay is obtained by puncturing the input and output of the employed channel code. The proposed code structure includes distributed Turbo codes and distributed serially concatenated codes as special cases. As the results of our optimization show, significant improvements in terms of rate and coverage are obtained. Compared to theoretical limits a decent performance is achieved considering that the focus is on feasibility.

关键词： adaptive coding Relays Turbo codes Concatenated codes Parity check codes Robustness Decoding Wireless sensor networks Convolutional codes Design optimization

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adaptive Modulation and coding for Free-Space Optical Channels

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JOURNAL OF OPTICAL COMMUNICATIONS AND NETWORKING 2010年第5期2卷 221-229页

作者： Djordjevic, Ivan B. Univ Arizona Dept Elect & Comp Engn Tucson AZ 85721 USA

adaptive modulation and coding can provide robust and spectrally efficient transmission over terrestrial free-space optical channels. Three adaptive modulation schemes are considered in this paper: (i) variable-rate variable-power adaptation, (ii) channel inversion, and (iii) truncated channel inversion schemes. It is shown that a simple channel inversion scheme performs comparable to a variable-rate variable-power adaptation scheme in the weak turbulence regime but faces significant performance degradation in the strong turbulence regime. We further study adaptive coding based on large-girth quasi-cyclic low-density parity-check- (LDPC-) coded modulation. It is shown by simulation that deep fades of the order of 30 dB and above in the regime of strong turbulence can be tolerated with the proposed scheme. It is demonstrated that communication in the saturation regime is possible with the proposed adaptive LDPC-coded modulation. We also determine the spectral efficiencies for the proposed adaptive modulation and adaptive coding schemes.

关键词： Atmospheric turbulence adaptive modulation adaptive coding Free-space optical (FSO) communications Low-density parity-check (LDPC) codes

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