多维MIMO数字系统的可达性观测性和噪声格拉姆矩阵

本文将二维系统的可达性格拉姆矩阵Ｋ，可观测性格拉姆矩阵Ｗ和噪声格拉姆矩阵ＷＮ推广到多维数字系统，导出了Ｗ与ＷＮ的显式关系式。文中证明，Ｋ和ＷＮ满足一对 修正的李晋曾诺夫矩阵方程，对于分母可分的系统，Ｋ和ＷＮ为分块对角阵，且可以通过求解李晋诺夫矩阵方程组而得。     

一类混沌电路的跃变参数识别与同步*

基于李亚普诺夫稳定性理论和矩阵理论,用两种方法对一类混沌电路系统参数发生跃变情况下的参数识别与同步控制进行了理论分析和数值计算机模拟。第一种方法是通过负反馈将系统镇定到某个稳定态来识别系统的跃变参数（系统参数突然发生阶跃性变化）,通过计算李亚普诺夫指数获得反馈系数临界值。第二种方法是基于李亚普诺夫稳定性理论得到的参数观测器包含了可调节的增益系数,当两个混沌系统达到完全同步时驱动系统的5个未知参数在阶跃变化情况下也可以被准确识别。最后对两种方法的优缺点进行了比较和分析。     

具有时延和丢包的不确定性NCS的稳定性

研究了同时具有网络时延和数据丢包的不确定网络化控制系统的稳定性.将数据丢失看成一种特殊的时延,利用动态反馈控制器设计提高系统的动态性能,得到了总时滞(包括传感器与控制器之间的时滞,控制器与执行器之间的时滞)的表达式,建立了不确定网络化控制系统模型.通过构造李亚普诺夫函数,采用线性矩阵不等式技巧,给出了系统稳定的判定定理.仿真结果表明了该方法的有效性.     

一种直线同步电机的控制方法

针对直线同步电机(LSM)控制系统,提出一种基于观测器的鲁棒控制方法。该方法首先建立了LSM矢量控制模型。然后利用李亚普诺夫方法,给出基于状态观测器的闭环控制系统鲁棒渐近稳定的充分条件,利用线性矩阵不等式处理方法,获得观测器和反馈控制器的参数。最后通过数值仿真,实验结果优于传统的控制方法,验证了该方法的正确性。     

低阻W／WN难熔栅技术研究

探索了新型难熔栅Ｗ／ＷＮ工艺制备技术,通过ＳＥＭ,ＸＲＤ,ＳＩＭＳ,ＸＰＳ等手段对ＷＮ,ＷＮ／ＧａＡｓ特性作了分析。结果表明,溅射气压和Ｎ分压对Ｗ,ＷＮ薄膜特性有着显著影响,通过工艺条件的优化,制备的Ｗ／ＷＮ膜厚为３６０ｎｍ,方块分压为０．５１Ω。利用ＳｉＯ２作为退火包封层,７８０℃ １０ｓ快速退火后,Ｗ／ＷＮ能够保持好的稳定性,在此基础上制备了肖特基二极管和自对准的ＧａＡｓ ＭＥＳＦＥＴ。     

一类非线性互联系统的H∞模型参考跟踪分散输出反馈模糊控制

本文对一类不确定状态不可测非线性互联系统,给出了一种基于观测器的H_∞模型参考跟踪分散输出反馈模糊控制方法.设计中,首先采用模糊不确定T-S模型对非线性互联系统进行模糊建模,在此基础上,给出模糊分散观测器的H_∞设计和基于观测器的模型参考跟踪分散模糊控制的设计.应用李亚普诺夫和线性矩阵不等式方法给出了模糊分散系统稳定的充分条件.仿真结果进一步验证了所提出的模糊分散控制方法的有效性.     

周期振子Chua电路的线性耦合同步

以非线性振子Chua电路为例,基于李亚普诺夫稳定性理论,研究了线性耦合实现两个系统之间的完全同步。进一步通过构造指数型李亚普诺夫函数验证了此线性控制器的可靠性,数值结果验证了此方法的有效性。系统达到同步所需的暂态过程,控制器的平均功耗与耦合强度的大小有关。     

继电器开关矩阵在导弹测试系统中的应用研究

以继电器开关矩阵的性能指标、实现方式以及模拟总线结构，重点描述了继电器开关矩阵在多型号导弹自动测试系统中的应用。通过软件灵活设置而不改动任何硬件，实现了不同测试流程中的多路数据采集，节约了测试系统的走线．增强了系统的可扩展性。     

随机变时滞神经网络的全局渐近稳定性

研究了一类具有变时滞随机神经网络模型平衡点的全局渐近稳定性问题,通过构造李亚普诺夫函数并利用线性矩阵不等式理论,得出了随机变时滞神经网络的全局渐近稳定性的充分条件。     

近距离热成像系统的光谱区配因数：——微分光谱匹配因数

导出了适用于近距离面目标热成像系统的微分光谱匹配因数Ｍ＾＊＝∫（αＷλＴ／αＴ）τａλτ０λλＤλ，且αＷλ／αＴ≈ｃ２／（λＴ＾２）·ＷλＴ。当Ｔ≈３００Ｋ，λ＝８￣１４ｕｍ时，αＷλＴ／αＴ≈０．０１６ＷλＴ；当Ｔ≈１０００Ｋ，λ＝３￣５ｕｍ时，αＷλＴ／αＴ≈０．００３６ＷλＴ。Ｍ决定热成像系统的温度分辨率：ＮＥＴＤ，ＭＲＴＤ，ＭＤＴＤ。     

Stability results for decomposable multidimensional digital systems based on the lyapunov equation

Lower bounds for the stability margins of 2-D digital systems are extended to n-D systems. These bounds are then improved for n-D (including 2-D) systems which have characteristic polynomials with 1-D factor polynomials. Stability analysis of n-D systems due to finite wordlength is considered, some tight lower bounds on coefficient wordlength which guarantee the n-D system to be stable and/or globally asymptotically stable are presented. Improved and/or extended criteria for absence of overflow oscillations and global asymptotic stability of n-D systems are proposed as well. An example is presented to illustrate the theoretical results, and it is shown that the lower bound on coefficient wordlength could be considerably improved for the (partial) factorable denominator n-D digital systems. All the discussions are based on the n-D Lyapunov equation.     

On Duality of Behavioural Systems

The notions of controllability and observability are duals in the traditional input-state-output framework of systems theory for 1-D systems. Recently, there has been a study on the duality between controllability and observability in behavioural systems [2] by the construction of a suitable adjoint for 1-D behavioural systems. In this paper we show, among other things, that formally this definition carries over also to n-D behavioural systems. We then explore the nature of the duality between controllability and observability for n-D systems using this definition of adjoint.     

Fast algorithms of multidimensional discrete nonseparable𝒦-wave transforms

Fast algorithms for a wide class of nonseparable n-dimensional (n-D) discrete unitary 𝒦 transforms (DKTs) are introduced. They need fewer 1-D DKTs than in the case of the classical radix-2 FFT-type approach. The method utilizes a decomposition of the n-D K transform into the product of a new n-D discrete Radon transform and of a set of parallel/independ 1-D K transforms. If the n-D K transform has a separable kernel (e.g., the case of the discrete Fourier transform), our approach leads to decrease of multiplicative complexity by the factor of n, compared with the classical row/column separable approach     

Channel Polarization: A Method for Constructing Capacity-Achieving Codes for Symmetric Binary-Input Memoryless Channels

A method is proposed, called channel polarization, to construct code sequences that achieve the symmetric capacity I(W) of any given binary-input discrete memoryless channel (B-DMC) W. The symmetric capacity is the highest rate achievable subject to using the input letters of the channel with equal probability. Channel polarization refers to the fact that it is possible to synthesize, out of N independent copies of a given B-DMC W, a second set of N binary-input channels {WN(i)1 les i les N} such that, as N becomes large, the fraction of indices i for which I(WN(i)) is near 1 approaches I(W) and the fraction for which I(WN(i)) is near 0 approaches 1-I(W). The polarized channels {WN(i)} are well-conditioned for channel coding: one need only send data at rate 1 through those with capacity near 1 and at rate 0 through the remaining. Codes constructed on the basis of this idea are called polar codes. The paper proves that, given any B-DMC W with I(W) > 0 and any target rate R< I(W) there exists a sequence of polar codes {Cfrn;nges1} such that Cfrn has block-length N=2n , rate ges R, and probability of block error under successive cancellation decoding bounded as Pe(N,R) les O(N-1/4) independently of the code rate. This performance is achievable by encoders and decoders with complexity O(N logN) for each.     

低阻W/WN难熔栅技术研究

探索了新型难熔栅 W/WN工艺制备技术 ,通过 SEM,XRD,SIMS,XPS等手段对WN,WN/Ga As特性作了分析。结果表明 ,溅射气压和 N分压对 W,WN薄膜特性有着显著影响 ,通过工艺条件的优化 ,制备的 W/WN膜厚为 36 0 nm,方块分压为 0 .5 1Ω。利用Si O2 作为退火包封层 ,780℃ 10 s快速退火后 ,W/WN能够保持好的稳定性 ,在此基础上制备了肖特基二极管和自对准的 Ga As MESF ET。     

Remarks on n -D Polynomial Matrix Factorization Problems

Multidimensional (n-D) polynomial matrix factorizations are intimately linked to many problems of multidimensional systems and signal processing. This paper gives a new result for a n-D polynomial matrix to have an minor prime factorization using methods from computer algebra. This result may be regarded as a generalization of a previous criterion under a special restriction [IEEE Trans. Circuits Syst. II: Exp Briefs, vol. 52, no. 9 (2005)]. Examples are given to illustrate results using computer algebra software system Singular.     

Transfer Function Computation for Multidimensional Systems

A theoretically interesting technique is proposed for the determination of the coefficients of the determinantal polynomial and the coefficients of the adjoint polynomial matrix of a given n-D system, described by the Fornasini-Marchesini state space model. The proposed algorithms are based on the discrete Fourier transform (DFT), and easily can be implemented. An example is included to illustrate the application of the algorithm.     

Four-dimensional spectral-spatial imaging using projection reconstruction

An n-dimensional (n-D) filtered backprojection image reconstruction algorithm has been developed and used in the reconstruction of 4-D spectral-spatial magnetic resonance imaging (MRI) data. The algorithm uses n-1 successive stages of 2-D filtered backprojection to reconstruct an n-D image. This approach results in a reduction in computational time on the order of N(n-2) relative to the single-stage technique, where N(n) is the number of elements in an n-D image. The authors describe implementation of the algorithm, including digital filtering and sampling requirements. Images obtained from simulated data are presented to illustrate the accuracy and potential utility of the technique.     

Conditions for Strong Stabilizabilities of n-Dimensional Systems

This paper presents two computational criteria concerning the strong stabilizabilities of SISO (single-input single-output) n-D shift-invariant systems. The first one is an alternative necessary and sufficient condition for an n-D system to be stabilizable by a stable complex controller, which is an explicitly computable geometric equivalent to the topological one recently derived by Shiva Shankar. The second one is a necessary and sufficient condition for the stabilizability by a stable real controller, which can be viewed as a generalization of the well-known Youla's parity interlacing property for the 1-D case. Furthermore, related prolems for computational testing of the criteria are summarized and some basic ideas on potential solution methods based on the cylindrical algebraic decomposition of algebraic varieties are outlined.