面向自适应码流的渐进编码方法的研究

多媒体信息呈几何级数的爆炸性增长,带来海量信息的同时也带来庞大的数据量,加重了网络的负担,同时不同用户对所要接收图像的质量要求有所不同,如果以相同的标准进行处理势必会造成一定程度上信息的浪费。文章对静止图像的渐进编码作了进一步的研究,对基本层和增强层采用不同的编码策略,更加适应网络复杂多变的带宽条件。文章还通过与用户之间的交互式操作来满足用户不同的需求。实验结果表明,在压缩效果达到JPEG压缩标准的情况下,增强了渐进功能,更加适应网络需要。     

Lattice Vector Quantization Applied to Speech and Audio Coding

Lattice vector quantization(LVQ) has been used for real-time speech and audio coding systems.Compared with conventional vector quantization,LVQ has two main advantages:It has a simple and fast encoding process,and it significantly reduces the amount of memory required.Therefore,LVQ is suitable for use in low-complexity speech and audio coding.In this paper,we describe the basic concepts of LVQ and its advantages over conventional vector quantization.We also describe some LVQ techniques that have been used in speech and audio coding standards of international standards developing organizations(SDOs).     

Efficient and High-quality Recommendations via Momentum-incorporated Parallel Stochastic Gradient Descent-Based Learning

A recommender system (RS) relying on latent factor analysis usually adopts stochastic gradient descent (SGD) as its learning algorithm. However, owing to its serial mechanism, an SGD algorithm suffers from low efficiency and scalability when handling large-scale industrial problems. Aiming at addressing this issue, this study proposes a momentum-incorporated parallel stochastic gradient descent (MPSGD) algorithm, whose main idea is two-fold: a) implementing parallelization via a novel data-splitting strategy, and b) accelerating convergence rate by integrating momentum effects into its training process. With it, an MPSGD-based latent factor (MLF) model is achieved, which is capable of performing efficient and high-quality recommendations. Experimental results on four high-dimensional and sparse matrices generated by industrial RS indicate that owing to an MPSGD algorithm, an MLF model outperforms the existing state-of-the-art ones in both computational efficiency and scalability.      

Improved macroblock level rate control for the spatially scalable extension of H.264/AVC

An improved rate control algorithm, designed for scalable video coders incorporating interlayer prediction, is proposed. Firstly, a Rate Distortion (RD) model for interlayer prediction involving the spatial enhancement layers is devised. An optimised Mean Absolute Difference (MAD) prediction model for the spatial enhancement layers that considers both the MAD from the spatial base layer in the same frame and the MAD from the corresponding macroblock in previous frames is also proposed. Simulation results show that the resulting algorithm produces accurate rate control with an average bit rate error of less than 0.26%. Compared with the JVT-W043 default rate control algorithm of the JSVM, the proposed algorithm improves the average PSNR by up to 0.53 dB or reduces the bit rate by an average of 10.95%. Furthermore, the proposed algorithm can be combined with the existing rate control scheme for H.264/AVC, resulting in further improvements.     

传真通信中MMR编码译码的实现

MMR编码技术是传真通信在发送端对图像进行分解、处理、调制，而在接收端进行解调、处理和传真图像合成而采用的一种编码方法，通过基本的软件语言来实现MMR编码与译码的基本功能。     

Capacity Region of a Class of Gaussian Cognitive Degraded Broadcast Channel

This paper studies the cognitive broadcast channel in which the primary user com- municates to the primary receiver, while the secondary user has noncausal knowledge of the primary radio＇s codeword and expects to communicate to two secondary receivers. Comparing with the existing cognitive radio channel which considers only one secondary receiver, cognitive broadcast channel studies the case that there are multiple secondary receivers. To this end, we investigate the fundamental limits of the performance of the Gaussian cognitive broadcast channel from the information theoretic perspective. Specifically, we derive the capacity region of the Gaussian cognitive degraded broadcast channel with weak interference.     

Efficient disparity vector prediction schemes with modified P frame for 2D camera arrays

An efficient disparity estimation algorithm for multi-view video sequences, recorded by a two-dimensional camera array in which the cameras are spaced equidistantly, is presented. Because of the strong geometrical relationship among views, the disparity vectors of a certain view can for most blocks be derived from the disparity vectors of other views. A frame constructed using that idea is called a D frame in this work. Three new prediction schemes which contain D frames are proposed for encoding 5 × 3 multi-view video sequences. The schemes are applied to several multi-view image sequences taken from a camera-array and they are compared in terms of quality, bit-rate and complexity. The experimental results show that the proposed prediction schemes significantly decrease the complexity of the encoder at a very low cost of quality and/or bit-rate.     

自动化立体仓库系统在飞机钣金模具管理中的应用

通过设计与规划自动化立体仓库管理系统,提出了以满足工段生产需求为目标的物流配送思想,以此思想为导向,优化模具管理流程,理顺内部客户关系,实现了飞机钣金零件模具的高效、准时配送。在飞机钣金模具管理中,与传统的模具仓库管理模式相比,自动化立体仓库系统节省了场地面积,降低了人工成本,提高了零件生产效率。