自适应Volterra滤波器的递归结构和类递归结构及其算法和应用

本文参考自适应IIR滤波器理论,提出了自适应Volterra滤波器(AVF)的递归结构和类递归结构,讨论了其特点和应用范围.递归结构的引入可显著减少AVF的参数和计算量.本文还给出了类递归结构AVF的在线辨识算法和在非线性系统辨识中的应用;给出了递归结构AVF的滤波算法和在非线性相关噪声抵消中的应用.在仿真实验中,将上述算法与多层感知器和非递归结构AVF做了对比.结果表明,本文算法住性能和计算量上均有明显优势。     

切比雪夫正交多项式神经网络的递归结构与类递归结构、算法及应用

本文针对信号处理中一类常用的非线性模型，提出了切比雪夫正交多项式神经网络（TOPNN）。与多层感知器（MLP）相比，其计算量可显著减少。本文还参考自适应IIR滤波器理论，提出了TOPNN的递归结构和类递归结构，讨论了其特点和应用范围。此外，本文还给出了（1）类递归结构TOPNN的在线辩识算法及其在非线性系统辩识中的应用，（2）递归结构TOPNN的滤波算法及其在非线性相关噪声抵消中的应用。最后在计算机仿真中将TOPNN与MLP进行了对比。     

Integrated structure/control design of mechatronic systems using a recursive experimental optimization method

A recursive experimental design method for simultaneously optimizing both mechanical structure and control is presented in this paper. Control gains are optimally tuned for a given prototype of mechatronic system, and its mechanical structure is physically modified so that control performance can be further improved. The entire control tuning, evaluation, and structure alteration process is repeated until the desired performance goals are achieved. In each iteration, incremental design changes are determined based on a sensitivity Jacobian relating structural changes to performance improvements. The sensitivity Jacobian is updated during the recursive process using the actual data of the design changes. To estimate the Jacobian despite few data points, a pseudoinverse method and a parameter perturbation algorithm, termed singular-value excitation, are developed. The mechanical structure is modified recursively and quickly by using structure reinforcement and rapid prototyping techniques. The feasibility of mechanical structure changes is taken into account in determining the design changes. The proposed methodology is verified through simulation and applied to the design of a robot positioning system. The robot arm structure is modified with regard to stiffness and damping by using steel reinforced epoxy. PD control gains are optimized every time the structure is modified. Through the recursive procedure, an optimal combination of the arm structure and control gains is obtained.     

Supervised learning sequential structure and parameter adaptive pattern recognition: Discrete data case (Corresp.)

In a previous paper [1], Bayes-optimal recursive supervised learning structure and parameter adaptive pattern recognition systems were derived for continuous "lumped" Gaussian processes. In this paper, the discrete data case is considered, and the discrete data version of the partition theorem is derived. Several examples are also presented of the application of the adaptive detectors, and computational results are given indicating their learning capacity and convergence rate.     

Multiprocessor multipath recursive filter structure with noincrease in computational complexity

An efficient delayed multipath recursive filter structure is proposed. Compared with conventional multiprocessor approaches, the new structure can achieve much higher throughput rate owing to its low computational complexity. Experimental results are taken using a system with four digital signal processors (DSPs)     

Error-free coefficient realisation of recursive part via input-partitioned filter structure

A new filter structure is developed which allows precise coefficient implementation in the recursive part of the system. This is achieved by partitioning the input sequence into sets of inputs and realising the recursive part of the system into parallel subfilters with precise pole realisation.     

A novel correlation adaptive receiver structure for high speed transmissions in ultra wide band systems with realistic channel estimation

Impulse radio ultra wide band (UWB) communications require robust receivers; typically Rake receivers are required to capture a large number of resolvable paths, (even hundred of paths), so large number of correlators are needed; otherwise, adaptive receivers use complex filters and channel estimation algorithms. Therefore, traditional Impulse radio receivers demand non-practical implementation structures. In this paper we propose a novel correlation-adaptive receiver structure with low complexity for indoor high speed ultra wide band systems. This novel structure combines correlation characteristics from Rake receivers with recursive filters from adaptive receivers. The receiver includes a low complexity recursive channel estimation filter capable of estimating hundreds of channel impulse responses, and a single filter-correlation filter used for coherent bit demodulation. Furthermore, we derive by simulations the bit error rate for high density multipath environments for several impulse radio modulations like TH-PPM, DS-BPSK and TH-BPSK and we compare the performance of the proposed structure with typical Rake receivers.     

用于低开销容错设计的存储部件可靠性评估研究

低开销容错技术是当前软错误研究领域的热点。为了对微处理器进行低开销容错保护,首先就需要对微处理器可靠性(即体系结构弱点因子AVF (Architectural Vulnerability Factor))进行准确评估。然而,现有的AVF评估工具的精确性和适用范围都受到不同程度的限制。该文以微处理器上的核心部件(即存储部件)作为研究对象,对AVF评估方法进行改进,提出了一种访存操作分析和指令分析相结合的AVF评估策略HAES (Hybrid AVF Evaluation Strategy)。该文将HAES融入到通用的模拟器中,实现了更精确和更通用的AVF评估框架。实验结果表明相比其它AVF评估工具,利用该文提出的评估框架得到的AVF平均降低22.6%。基于该评估框架计算得到的AVF更加精确地反映了不同应用程序运行时存储部件的可靠性,对设计人员对微处理器进行低开销的容错设计具有重要指导意义。     

Study of periodic band gap structure of the magnetized plasma photonic crystals

The characteristics of the periodic band gaps of the one dimension magnetized plasma photonic crystals are studied with the piecewise linear current density recursive convolution (PLCDRC) finite-differential time-domain (FDTD) method. In frequency-domain, the transmission coefficients of electromagnetic Gaussian pulses are computed, and the effects of the periodic structure constant, plasma layer thickness and parameters of plasma on the properties of periodic band gaps of magnetized photonic crystals are a...     

运用递归算法实现共用的MDCT和IMDCT结构

在MPEG音频编码标准中，前向MDCT和后向MDCT是2个计算最复杂的部分。提出了一种有效的递归算法来同时实现任意长度的前向MDCT和后向MDCT。由于递归算法本身的特性，所提出的结构非常适合并行VLSI的实现。     

3D structure from 2D motion

This article motivates the structure from motion (SfM) approaches by describing some current practical applications. This is followed by a brief discussion of the background of the field. Then, several techniques are outlined that show various important approaches and paradigms to the SfM problem. Critical issues, advantages and disadvantages are pointed out. Subsequently, we present our SfM approach for recursive estimation of motion, structure, and camera geometry in a nonlinear dynamic system framework. Results are given for synthetic and real images. These are used to assess the accuracy and stability of the technique. We then discuss some practical and real-time applications we have encountered and the reliability and flexibility of the approach in those settings. Finally, we conclude with results from an independent evaluation study conducted by industry where the proposed SfM algorithm compared favorably to alternative approaches     

Design Of 2-D Recursive Digital Filters Using Nonsymmetric Half-Plane Allpass Filters

A novel structure using recursive nonsymmetric half-plane (NSHP) digital allpass filters (DAFs) is presented for designing 2-D recursive digital filters. First, several important properties of 2-D recursive DAFs with NSHP support regions for filter coefficients are investigated. The stability of the 2-D recursive NSHP DAFs is guaranteed by using a spectral factorization-based algorithm. Then, the important characteristics regarding the proposed novel structure are discussed. The design problem of 2-D recursive digital filters using the novel structure is considered. We formulate the problem by forming an objective function consisting of the weighted sum of magnitude, group delay, and stability-related errors. A design technique using a trust-region Newton-conjugate gradient method in conjunction with the analytic derivatives of the objective function is presented to efficiently solve the resulting optimization problem. The novelty of the presented 2-D structure is that it possesses the advantage of better performance in designing a variety of 2-D recursive digital filters over existing 2-D filter structures. Finally, several design examples are provided for conducting illustration and comparison.     

Walsh Summing and Differencing Transforms

Analogous to Fourier frequency transforms of the integration and differentiation of a continuous-time function, Walsh sequency transforms of the summing and differencing of an arbitrary discrete-time function have been derived. These transforms can be represented numerically in the form of matrices of simple recursive structure. The matrices are not orthogonal, but they are the inverse of each other, and the value of their determinants is one.     

Dependence of the error performance of turbo-codes on theinterleaver structure in short frame transmission systems

The dependence of both bit and frame error performance, respectively, of the novel parallel concatenated recursive systematic codes, termed turbo-codes, on the interleaver structure is investigated in frame transmission systems with frames containing 192 bits required for speech transmission in a possible future mobile radio system     

多层压电结构中声表面波特性的计算

The propagation properties of the surface acoustic waves(SAWs) in a ZnO-SiO2-Si multilayered piezoelectric structure are calculated by using the recursive asymptotic method.The phase velocities and the electromechanical coupling coefficients for the Rayleigh wave and the Love wave in the different ZnO-SiO2-Si structures are calculated and analyzed.The Love mode wave is found to be predominantly generated since the c-axis of the ZnO film is generally perpendicular to the substrate.In order to prove the calculated results,a Love mode SAW device based on the ZnO-SiO2-Si multilayered structure is fabricated by micromachining,and its frequency responses are detected.The experimental results are found to be mainly consistent with the calculated ones,except for the slightly larger velocities induced by the residual stresses produced in the fabrication process of the films.The deviation of the experimental results from the calculated ones is reduced by thermal annealing.     

温度、密度对磁化等离子体光子晶体的影响

为了研究温度、密度对磁化等离子体光子晶体禁带特性的影响,采用在等温近似的条件下,磁化等离子体的分段线形电流密度卷积时域有限差分算法研究了1维磁化等离子体光子晶体的禁带特性。以高斯脉冲为激励源,用算法公式得到的电磁波透射系数来讨论了温度、等离子体层密度对其禁带特性的影响。结果表明,改变温度和等离子体层密度分布可以实现对禁带的控制。     

Modular bipolar analysis: Part I—Theory

A set of general recursive equations that are used with a generalized modular model is described. The model is used to analyze realistic bipolar junction devices from their physical geometries and impurity profiles. An individual device is partitioned into simple one-dimensional modules which enables the closed recursive equations to be used in solving for each module's electrical parameters. A companion paper describes how the individual module parameters are then superimposed upon the physical structure to obtain the intrinsic parameters that electrically represents the bipolar junction device. The device can be fully analyzed on any circuit analysis program by adding its appropriate bulk resistances and junction capacitances.     

Single Filter Frequency Masking High-Speed Recursive Digital Filters

For recursive filter the maximal sample frequency is bounded by the recursive loops in the filter. [In this paper, it is understood that recursive filters are infinite-length impulse response (IIR) filters.] In this work, a filter structure based on the use of the frequency masking approach is presented that increases the maximal sample frequency for narrowband and wideband filters by introducing more delay elements in the recursive loops. By using identical subfilters (except for the periods), the subfilters can be mapped using folding to a single pipeline/interleaved arithmetic structure yielding an area-efficient implementation. The filters are potentially suitable for low-power implementation by using power supply voltage scaling techniques. In this work, the design of the filters is discussed and estimations of the ripples are derived. Two examples show the viability of the proposed method.     

Recursive weighted median filters admitting negative weights andtheir optimization

A recursive weighted median (RWM) filter structure admitting negative weights is introduced. Much like the sample median is analogous to the sample mean, the proposed class of RWM filters is analogous to the class of infinite impulse response (IIR) linear filters. RWM filters provide advantages over linear IIR filters, offering near perfect “stopband” characteristics and robustness against noise. Unlike linear IIR filters, RWM filters are always stable under the bounded-input bounded-output criterion, regardless of the values taken by the feedback filter weights. RWM filters also offer a number of advantages over their nonrecursive counterparts, including a significant reduction in computational complexity, increased robustness to noise, and the ability to model “resonant” or vibratory behavior. A novel “recursive decoupling” adaptive optimization algorithm for the design of this class of recursive WM filters is also introduced. Several properties of RWM filters are presented, and a number of simulations are included to illustrate the advantages of RWM filters over their nonrecursive counterparts and IIR linear filters     

New Recursive Algorithms for the Unified Forward and Inverse MDCT/MDST

Forward and inverse MDCT are two of the most computationally intensive operations in the MPEG audio coding standard. In this paper we derive sinusoidal recursive formulas for transforming kernels of the MDCT/MDST and IMDCT/IMDST. Then we efficiently implement MDCT/MDST and IMDCT/IMDST of the general length using the regressive structure derived from the sinusoidal recursive formulas. The proposed regular structure is particularly suitable for parallel VLSI realization. Our solution requires significantly less operations as well as less hardware compared with a recently proposed one.