Implementation of RNS-Based Distributed Arithmetic Discrete Wavelet Transform Architectures Using Field-Programmable Logic

Currently there are design barriers inhibiting the implementation of high-precision digital signal processing (DSP) objects with field programmable logic (FPL) devices. This paper explores overcoming these barriers by fusing together the popular distributed arithmetic (DA) method with the residue number system (RNS) for use in FPL-centric designs. The new design paradigm is studied in the context of a high-performance filter bank and a discrete wavelet transform (DWT). The proposed design paradigm is facilitated by a new RNS accumulator structure based on a carry save adder (CSA). The reported methodology also introduces a polyphase filter structure that results in a reduced look-up table (LUT) budget. The 2C-DA and RNS-DA are compared, in the context of a FPL implementation strategy, using a discrete wavelet transform (DWT) filter bank as a common design theme. The results show that the RNS-DA, compared to a traditional 2C-DA design, enjoys a performance advantage that increases with precision (wordlength).     

Vinyl acetate monomer—a pilot plant study

The kinetics of the reaction of acetic acid and acetylene over zinc acetate-activated carbon catalyst was investigated over a wide range of process variables in a pilot reactor. Although various catalytic reaction mechanisms were postulated, the rate of reaction was most satisfactorily correlated by a mechanism of surface reaction between charged adsorbed acetic acid and acetylene, which assumes that the rate controlling step was the irreversible charged adsorption of acetylene and acetic acid.     

美国能源部的浆态床F－T合成技术

浆态床Ｆ－Ｔ合成技术是美国能源部Ｆ－Ｔ合成技术的主要开发项目。本文就浆态相Ｆ－Ｔ合成催化剂的开发、中试示范实验和浆态反应器的化工基础研究作一扼要的介绍。     

Discrete element approach for mine dump stability analysis

Mine overburden dumps have posed significant safety issues in the operations of various unit operations of open pit min-ing especially the external dumps. The external dumps are composed of a mixture of fragmented rocks and loose soil. Their charac-teristic is comparable to heavily discontinuous solid mass. The conventional approach of limit equilibrium methods provide safety factors for the slope but nothing about the stress-strain characteristics of the large dump mass. The designs of dump location and their respective geometry are integrated for the know-how of the stability characteristics of these dumps. The discrete element method uses a circular disk to represent the granular solid mass and their interactions are described by the Newton's third law of motion. The displacement is described by the sliding of the circular disk. This work is focused on the modeling efficiency of the discrete element methods to represent the behaviour of mine dump masses with the specified joint plane for the limit equilibrium method. The advantage of the work lies on the ease of information retrieval at any point at the dump mass concerning the stress and strain histories, displacement, failures etc. which when integrated produces a better understanding of the stability of the dump masses.     

DCT- and DST-based splitting methods for Toeplitz systems

New splitting iterative methods for Toeplitz systems are proposed by means of recently developed matrix splittings based on discrete sine and cosine transforms due to Kailath and Olshevsky [Displacement structure approach to discrete-trigonometric transform-based preconditioners of G. Strang type and of T. Chan type, SIAM J. Matrix Anal. Appl. 26 (2005), pp. 706–734]. Theoretical analysis shows that new splitting iterative methods converge to the unique solution of a symmetric Toeplitz linear system. Moreover, an upper bound of the contraction factor of our new splitting iterations is derived. Numerical examples are reported to illustrate the effectiveness of new splitting iterative methods.     

Stability analysis in a second-order differential equation with delays

A second-order differential equation with finite discrete delays is considered. Local stability of the zero equilibrium is investigated, and we obtain some sufficient conditions for the zero equilibrium is stable or unstable. Moreover, it is found that there exist the local Hopf bifurcations of the system when the delay varies.     

基于SVD、DCT和RSA加密数字水印算法研究

提出了一种基于SVD、DCT、RSA加密数字水印算法,该方法是将载体文档图像做8＊8块的DCT变换,水印图像进行了Arnold处理,将水印图像嵌入到变换的SVD正定矩阵中,修改中频域频谱系数,同时对文档使用RSA算法进行加密,含有水印的图像经IDCT变换存成嵌入水印的图像。通过提取变换域的SVD,提取数字水印,经过RSA算法加密后解密该文档,在经过猫脸逆变换处理得到数字水印图像,水印图像的提取IDCT实验结果表明,本文算法具有安全性高、鲁棒性强以及嵌入水印较好的视觉隐蔽特性、算法处理速度快等特点。     

巨型浮吊船电力系统动态响应的联想记忆识别

巨型浮吊海洋工程船的作业依赖于船舶电力系统的稳定运行。这类船上大功率变频器、大功率交流电机等设备的大量应用,使得控制系统受干扰影响严重,检测到的动态响应常常含有干扰成分,给电力自动化设备的反馈控制带来了困难。联想记忆具有按信息内容检索的功能,可以模仿人脑进行联想,处理缺损和不确定的信息,具有容错功能。根据联想记忆原理,运用Hopfield网络结构,对Hebb学习规则进行了改进,构建了自联想离散Hopfield网络。该网络通过对动态响应标准样本进行学习,得到了稳定模式,在受干扰污染、信息缺损的巨型浮吊船电力系统动态响应的识别中表现出了良好的滤除干扰的能力。     

Permeability analysis of fractured vuggy porous media based on homogenization theory

Based on the characteristics of fractured vuggy porous media,a novel mathematical model was proposed to model fluid flow in such media on fine scale,i.e.,the discrete fracture-vug network model.The new model consists of three systems:porous rock system,fracture system,and vug system.The fractures and vugs are embedded in porous rock,and the isolated vugs could be connected via the discrete fracture network.The flow in porous rock and fractures follows Darcy's law,and the vugs system is free fluid region.Usi...     

高速补充信道对cdma2000-1x前向链路功率分配的影响

分析了cdma2000-1x系统的前向信道发射功率分配。通过仿真试验及理论推导，给出了导频信道和业务信道信号质量之间的相互依赖关系并绘出导频信号和业务信道之间的相关性曲线：根据这种相关性曲线，从而发现使总发射功率最小的最佳导频功率；最后提出并分析了高速补充信道对cdma2000-1x前向链路功率分配的影响。