Joint Wyner–Ziv/Dirty-Paper Coding by Modulo-Lattice Modulation

The combination of source coding with decoder side information (the Wyner-Ziv problem) and channel coding with encoder side information (the Gel'fand-Pinsker problem) can be optimally solved using the separation principle. In this work, we show an alternative scheme for the quadratic-Gaussian case, which merges source and channel coding. This scheme achieves the optimal performance by applying a modulo-lattice modulation to the analog source. Thus, it saves the complexity of quantization and channel decoding, and remains with the task of ldquoshapingrdquo only. Furthermore, for high signal-to-noise ratio (SNR), the scheme approaches the optimal performance using an SNR-independent encoder, thus it proves for this special case the feasibility of universal joint source-channel coding.     

Quantifying the Loss of Compress–Forward Relaying Without Wyner–Ziv Coding

The compress-and-forward (CF) strategy achieves the optimal diversity–multiplexing tradeoff (DMT) of a three-node half-duplex relay network in slow fading, under the assumption that the relay has perfect knowledge of all three channel coefficients and that the relay makes use of Wyner–Ziv (WZ) source coding with side information. This paper studies the achievable DMT of the same network when the relay is constrained to make use of standard (non-WZ) source coding. Under a short-term power constraint at the relay, using source coding without side information results in a significant loss in terms of the DMT. For multiplexing gains $r leq {2over 3}$, this loss can be fully compensated for by using power control at the relay. On the contrary, for $r in ({2over 3},1)$, the loss with respect to WZ coding remains significant.      

Adaptive Correlation Noise Model for DC Coefficients in Wyner‐Ziv Video Coding

An adaptive correlation noise model (CNM) construction algorithm is proposed in this paper to increase the efficiency of parity bits for correcting errors of the side information in transform domain Wyner‐Ziv (WZ) video coding. The proposed algorithm introduces two techniques to improve the accuracy of the CNM. First, it calculates the mean of direct current (DC) coefficients of the original WZ frame at the encoder and uses it to assist the decoder to calculate the CNM parameters. Second, by considering the statistical property of the transform domain correlation noise and the motion characteristic of the frame, the algorithm adaptively models the DC coefficients of the correlation noise with the Gaussian distribution for the low motion frames and the Laplacian distribution for the high motion frames, respectively. With these techniques, the proposed algorithm is able to make a more accurate approximation to the real distribution of the correlation noise at the expense of a very slight increment to the coding complexity. The simulation results show that the proposed algorithm can improve the average peak signal‐to‐noise ratio of the decoded WZ frames by 0.5 dB to 1.5 dB.     

Rate Region of the Quadratic Gaussian Two-Encoder Source-Coding Problem

We determine the rate region of the quadratic Gaussian two-encoder source-coding problem. This rate region is achieved by a simple architecture that separates the analog and digital aspects of the compression. Furthermore, this architecture requires higher rates to send a Gaussian source than it does to send any other source with the same covariance. Our techniques can also be used to determine the sum-rate of some generalizations of this classical problem. Our approach involves coupling the problem to a quadratic Gaussian ldquoCEO problem.rdquo     

The Application of Successive Quadratic Programming Algorithm to Multiuser Detection in CDMA

In this paper, based on the semidefinite programming relaxation of the CDMA maximum likelihood (ML) multiuser detection problem, a detection strategy by the successive quadratic programming algorithm is presented. Coupled with the randomized cut generation scheme, we obtain the suboptimal solution of multiuser detection problem. Comparing with the reported interior point methods based on semidefinite programming, simulations demonstrate that the successive quadratic programming algorithm often yields the similar BER performances of the multiuser detection problem. But the average CPU time of this approach is significantly reduced. Xuewen Mu received the MS degree in applied mathematics from the Xidian University in 2004 and the PhD degree in applied mathematics in 2006. His current research interests include the applications of the semidefinite programming and the combinatorial programming.     

A New Segment Quantization Using Lempel–Ziv Algorithm and Its Application to Quantization of Line Spectral Frequencies

A new segment quantization method using the Lempel-Ziv algorithm is proposed, and it is applied to quantize line spectral frequency parameters in speech codec. The proposed segment quantizer can save four bits per frame, compared with the ITU-T G.729 speech codec (18 bits/frame), without degradation of subjective or objective speech quality     

Coding for the Feedback Gel'fand–Pinsker Channel and the Feedforward Wyner–Ziv Source

We consider both channel coding and source coding, with perfect past feedback/feedforward, in the presence of side information. It is first observed that feedback does not increase the capacity of the Gel'fand-Pinsker channel, nor does feedforward improve the achievable rate-distortion performance in the Wyner-Ziv problem. We then focus on the Gaussian case showing that, as in the absence of side information, feedback/feedforward allows to efficiently attain the respective performance limits. In particular, we derive schemes via variations on that of Schalkwijk and Kailath. These variants, which are as simple as their origin and require no binning, are shown to achieve, respectively, the capacity of Costa's channel, and the Wyner-Ziv rate distortion function. Finally, we consider the finite-alphabet setting and derive schemes for both the channel and the source coding problems that attain the fundamental limits, using variations on schemes of Ahlswede and Ooi and Wornell, and of Martinian and Wornell, respectively     

Catch 22问题及其解决方案

研究了密码学中的Catch22问题及其经典和量子密码解决方案,特别研究了量子密码解决方案。研究表明:经典密码学不能完全解决Catch 22问题,而建立在量子力学基础上的量子密码学能提供一个较好的解决方案。     

序号预测矢量量化器及其在图象编码中应用

本文提出一种序号预测矢量量化器的结构，与一般矢量量化器相比，它充分利用了图象极强的二维相关特性，并采用预测的方法去除冗余码字，从而在保证译码图象质量与一般矢量量化器的译码图象质量相同的前提下，压缩比可提高一倍以上。     

A Simple Polynomial Approximation to the Gaussian Q-function and Its Application

A simple polynomial approximation to the Gaussian Q-function is proposed, based on the observation that a Gaussian random variable can be well approximated by a sum of uniform random variables. The approximation can be used to obtain accurate explicit approximations to problems that otherwise do not have explicit solutions or approximate explicit solutions. As an example, an explicit expression for the average symbol error rate of M-ary pulse amplitude modulation in lognormal channels is derived using the new approximation, and the approximate symbol error rate is shown to be very close to the exact value.     

关于稀疏编码理论及其应用

稀疏编码的概念源于视神经网络的研究,是对只有一小部分神经元同时处于活跃状态的多维数据的神经网络的表示方法。稀疏编码理论在视神经细胞的响应特性和外部环境刺激的统计特性之间建立一种科学的数量联系,逐渐成为了一种有效理解人类神经系统信息加工机制的理论工具,在盲源信号分离、语音信号处理、图像特征提取、自然图像去噪、以及模式识别等方面取得了许多成果,具有重要的实用价值。     

一种新的视频编码二次率失真模型及其性能分析

基于对视频编码比特率与内容复杂度之间关系的研究,该文提出了一种新的视频编码二次率失真模型。该模型保留泰勒级数中的常数项,并通过合理引入内容复杂度,提高了描述实际信源率失真特性的准确性。大量实验分析表明该模型具有良好的性能,可广泛应用于各种速率控制算法以及其他使用率失真模型的场合,以提高视频编码器的率失真性能。     

分层视频编码技术及其在网络传输中的应用

本文对分层编码技术的工作原理进行了初步分析与探讨,并对分层视频数据流如何在网络中进行有效传输进行了描述。     

基于FGSE的快速分形图像编码算法及其多描述编码方案

本文在基于分形图像编码的多描述编码方案（MDFIC）的基础上,做了两处改进：一是引入提出的基于FGSE的快速分形图像编码算法,以提高编码速度;二是利用相邻值域块均值间的相关性,以减少比特率。实验结果表明,本方案与MDFIC相比,可以在保持解码图像质量几乎不变的情况下,提高编码速度和减少比特率,并具有较高的鲁棒性。     

先进便携式多媒体编码技术与应用(上)

在先进的数字压缩技术问世之前,根本不可能以经济的成本为消费者提供高质量的数字视频.MPEG针对数字音频和视频的编码原则制定了MPEG标准,从而改变了这一状况.MMEG压缩引擎能够成本经济地为消费者传输数字多媒体内容.这一标准的制定为多媒体市场带来了无限商机.您了解MPEG-4技术吗?如何才能利用这一技术在市场上占据一席之地呢?     

先进便携式多媒体编码技术与应用(下)

H.264/AVC标准的主要技术 帧间预测(Intra-frame Prediction) 根据每个宏块的片编码类型的不同,可以以几种编码类型中的一种进行传输.所有片编码类型可支持两种类别的帧内编码类型,分别为INTRA-4×4和INTRA-16×16.在以往的视频编码标准中,预测操作都是在转换域中进行的,与此不同,在H.264/AVC标准中,预测操作往往是根据已编码块中的相邻样本,在空间域中进行的.     

AVS视频编码标准及其在直播卫星中的应用

本文详细论述了AVS视频编码标准的主要技术特点,并且通过与MPEG-2和H.264在技术性能方面的比较,得出了我国自主研发的编码标准AVS在复杂度和专利许可费方面优于现行标准的结论.最后还简要论述了AVS标准在广播电视直播卫星中的应用,可以看出AVS在卫星数字电视方面有很大应用前景.     

On the Linear Codebook-Level Duality Between Slepian–Wolf Coding and Channel Coding

In this paper, it is shown that each Slepian–Wolf coding problem is related to a dual channel coding problem in the sense that the sphere packing exponents, random coding exponents, and correct decoding exponents in these two problems are mirror-symmetrical to each other. This mirror symmetry is interpreted as a manifestation of the linear codebook-level duality between Slepian–Wolf coding and channel coding. Furthermore, this duality, in conjunction with a systematic analysis of the expurgated exponents, reveals that nonlinear Slepian–Wolf codes can strictly outperform linear Slepian–Wolf codes in terms of rate-error tradeoff at high rates. The linear codebook-level duality is also established for general sources and channels.      

Absolute Moment Block Truncation Coding and Its Application to Color Images

A new quantization method that uses the criterion of preserving sample absolute moments is presented. This is based on the same basic idea for block truncation coding of Delp and Mitchell but it is simpler in any practical implementation. Moreover, output equations are those for a two-level nonparametric minimum mean square error quantizer when the threshold is fixed to the sample mean. The application of this method to single frame color images is developed. A color image coding system that uses absolute moment block truncation coding of luminance and chroma information is presented. Resulting color images show reasonable performance with bit rates as low as 2.13 bits/pixel.     

SYBASE数据库的锁定机制及其应用

锁定机制是关系数据库中数据操作的一个关键技术。以ＳＹＢＡＳＥ Ｓｑｌ／Ａｄａｐｔｉｖｅ Ｓｅｒｖｅｒ数据库为例,并结合甘肃省移动计费软件中的详情话单处理模块介绍了锁定机制及其应用。