In this paper, we discuss two-stage encoding algorithms capable of correcting a fraction of asymmetric errors. Suppose that the encoder transmits n binary symbols (x(1), ..., x(n)) one-by-one over the Z-channel, in wh...
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In this paper, we discuss two-stage encoding algorithms capable of correcting a fraction of asymmetric errors. Suppose that the encoder transmits n binary symbols (x(1), ..., x(n)) one-by-one over the Z-channel, in which a 1 is received only if a 1 is transmitted. At some designated moment, say n(1), the encoder uses noiseless feedback and adjusts further encoding strategy based on the partial output of the channel (y(1), ..., yn(1)). The goal is to transmit error-free as much information as possible under the assumption that the total number of errors inflicted by the Z-channel is limited by tau n, 0 < tau < 1. We propose an encoding strategy that uses a list-decodable code at the first stage and a high-error low-rate code at the second stage. This strategy and our converse result yield that there is a sharp transition at tau = max(0two-stage encoding strategies. As side results, we derive bounds on the size of list-decodable codes for the Z-channel and prove that for a fraction 1/4 + epsilon of asymmetric errors, an error-correcting code contains at most O(epsilon(-3/2)) codewords.
Lossless video coding is used when perfect preservation of video data is required. In HEVC, lossless coding is accomplished by bypassing the transform and quantization stages. Prediction residuals are coded with the e...
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ISBN:
(纸本)9781479957521
Lossless video coding is used when perfect preservation of video data is required. In HEVC, lossless coding is accomplished by bypassing the transform and quantization stages. Prediction residuals are coded with the entropy coder in the spatial domain. In this paper, two-stage coding with sub-frame adaptive quantization is proposed. The DCT is firstly applied to the prediction residuals and the DCT coefficients are quantized. The quantized DCT coefficients and the quantization error are coded. Adaptive quantization parameters are used for each coding Unit. Simulation results show that the proposed method significantly outperforms the HEVC lossless coding.
In the problem of flexible flow shop scheduling with variable processing times, the change of processing speed often affects product quality and causes fluctuations in capacity, which makes it difficult to solve the s...
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In the problem of flexible flow shop scheduling with variable processing times, the change of processing speed often affects product quality and causes fluctuations in capacity, which makes it difficult to solve the scheduling problem. In the light of the flexible flow-shop scheduling problem with variable processing times (FFSP-VPT), the FFSP-VPT mathematical model is established. The improved differential shuffled frog leaping algorithm (DSFLA) serves as the global optimisation algorithm. It overcomes the shortcomings of the adaptive shuffled frog leaping algorithm which easily falls into local optimum and converges slowly. The two-stage coding method is used to determine the online sequence of the job and processing speed of the stage with variable processing times. The simulation experiments confirm the improvement of the shuffled frog leaping algorithm in global search ability and its effectiveness in solving the flexible flow shop scheduling problem with variable processing times.
The dimensionality of light field data is typically very large for efficient implementation of sparse representation algorithms, such as for dictionary training and sparse coding. We propose a framework for creating l...
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ISBN:
(纸本)9781479946129
The dimensionality of light field data is typically very large for efficient implementation of sparse representation algorithms, such as for dictionary training and sparse coding. We propose a framework for creating light field dictionary using the method of perspective-shearing. Such a dictionary has a special organized structure for different central view patterns and perspective disparities. Based on this dictionary structure, a two-stage sparse coding algorithm is proposed to speed up the reconstruction process by incorporating an interim Winner-Take-All (WTA) hash codingstage into the Orthogonal Matching Pursuit (OMP) algorithm;this stage proves to speed up the sparse coding process by almost three times but still maintains the reconstruction quality. The proposed scheme produces impressive light field reconstruction qualities for compressed light field sensing.
We describe a general, coding strategy leading to a family of universal image compression systems designed to give good performance in applications where the statistics of the source to be compressed are not available...
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We describe a general, coding strategy leading to a family of universal image compression systems designed to give good performance in applications where the statistics of the source to be compressed are not available at design time or vary over time or space. The basic approach considered uses a two-stage structure in which the single source code of traditional image compression systems is replaced with a family of codes designed to cover a large class of possible sources. To illustrate this approach, we consider the optimal design and use of two-stage codes containing collections of vector quantizers (weighted universal vector quantization), bit allocations for JPEG-style coding (weighted universal bit allocation), and transform codes (weighted universal transform coding). Further, we demonstrate the benefits to be gained from the inclusion of perceptual distortion measures and optimal parsing. The strategy yields two-stage codes that significantly outperform their single-stage predecessors. On a sequence of medical images, weighted universal vector quantization outperforms entropy coded vector quantization by over 9 dB, On the same data sequence, weighted universal bit allocation outperforms a JPEG-style code by over 2.5 dB. On a collection of mixed text and image data, weighted universal transform coding outperforms a single, data-optimized transform code (which gives performance almost identical to that of JPEG) by over 6 dB.
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