汉明码检验系统的电路实现

本文首先介绍了汉明码的特点和编码规则,并以此为基础着重讨论了一个(15,11)的汉明码检测系统的数字电路实现过程。     

Benchmarking access methods for time-evolving regional data

In this paper we present a performance comparison of access methods for time-evolving regional data. Initially, we briefly review four temporal extensions of the Linear Region Quadtree: the Time-Split Linear Quadtree, the Multiversion Linear Quadtree, the Multiversion Access Structure for Evolving Raster Images and Overlapping Linear Quadtrees. These methods comprise a family of specialized access methods that can efficiently store and manipulate consecutive raster images. A new simpler implementation solution that provides efficient support for spatio-temporal queries referring to the past through these methods, is suggested. An extensive experimental space and time performance comparison of all the above access methods follows. The comparison is made under a common and flexible benchmarking environment in order to choose the best technique depending on the application and on the image characteristics. These experimental results show that in most cases the Overlapping Linear Quadtrees method is the best choice.     

一个结构分解算法及其在解耦问题中的应用

一个结构分解算法及其在解耦问题中的应用１）孙振东夏小华（北京航空航天大学七研北京１０００８３）关键词线性系统，无穷结构，Ｍｏｒｇａｎ问题，Ｓｉｎｇｈ算法．１）国家自然科学基金资助的课题．初稿曾在１９９５年控制与决策年会上宣读．收稿日期１９９５－０４－...     

On the algebraic identifiability of finite impulse response channels driven by linearly precoded signals

It is common in wireless communications to perform some form of linear precoding operation on the source signal prior to transmission over a channel. Although the traditional reason for precoding is to improve the performance of the communication system, this paper draws attention to the fact that the receiver can identify the impulse response of the channel without any prior knowledge of the transmitted signal simply by solving a system of polynomial equations. Since different precoders lead to different systems of equations, this paper addresses the fundamental issue of determining which classes of linear precoders lead to a system of equations having a unique solution. In doing so, basic properties of polynomial equations which are useful for studying other identifiability issues commonly encountered in engineering and the applied sciences are presented.     

Out of order quantifier elimination for Standard Quantified Linear Programs

In this paper, we present an out of order quantifier elimination algorithm for a class of Quantified Linear Programs (QLPs) called Standard Quantified Linear Programs (SQLPs). QLPs in general and SQLPs in particular are extremely useful constraint logic programming structures that find wide applicability in the modeling of real-time schedulability specifications; see Subramani [Subramani, K., 2005a. A comprehensive framework for specifying clairvoyance, constraints and periodicity in real-time scheduling. The Computer Journal 48 (3), 259–272]. Consequently any algorithmic advance in their solution has a strong practical impact. Prior to this work, the only known approaches to the solution of QLPs involved sequential variable elimination; see Subramani [Subramani, K., 2003b. An analysis of quantified linear programs. In: Calude, C.S. et al. (Eds.), Proceedings of the 4th International Conference on Discrete Mathematics and Theoretical Computer Science. DMTCS. In: Lecture Notes in Computer Science, vol. 2731. Springer-Verlag, pp. 265–277]. In the sequential approach, the innermost quantified variable is eliminated first, followed by the variable which then becomes the innermost quantified variable and so on, until we are left with a single variable from which the satisfiability of the original formula is easily deduced. This approach is applicable in both discrete and continuous domains; however, it is to be noted that the logic demanding the sequential approach requires that the variables are discrete-valued. To the best of our knowledge, the necessity for sequential elimination over continuous-valued variables has not been investigated in the literature. The techniques used in the development of our elimination algorithm may find applications in domains such as classical logic and finite model theory. The final aspect of our research concerns the structure-preserving nature of the algorithm that we introduce here; in general, it is not known whether discrete domains admit such elimination procedures.     

Periodic output feedback stabilization of single-input single-output continuous-time systems with odd relative degree

The paper considers the long-standing open problem of static output feedback stabilization with periodic output feedback. Extending the tools from vibrational control theory, we are able to derive some original results for this problem. We provide some sufficient conditions for stabilization with periodic output feedback. The proposed approach is constructive, and for some low dimensional cases, the sufficient conditions that we present are also necessary.     

基于LDA算法的人脸识别方法的比较研究

线性判别分析（LDA）是一种较为普遍的用于特征提取的线性分类方法。但是将LDA直接用于人脸识别会遇到维数问题和“小样本”问题。人们经过研究，通过多种途径解决了这两个问题并实现了基于LDA的人脸识别。文章对几种基于LDA的人脸识别方法做了理论上的比较和实验数据的支持，这些方法包括Eigenfaces、Fisherfaces、DLDA、VDLDA及VDFLDA。实验结果表明VDFLDA是其中最好的一种方法。     

A systolic algorithm for solving dense linear systems

For an arbitrary n × n matrix A and an n × 1 column vector b, we present a systolic algorithm to solve the dense linear equations Ax = b. An important consideration is that the pivot row can be changed during the execution of our systolic algorithm. The computational model consists of n linear systolic arrays. For 1 ≤ i ≤ n, the i^th linear array is responsible to eliminate the i^th unknown variable x_i of x. This algorithm requires 4n time steps to solve the linear system. The elapsed time unit within a time step is independent of the problem size n. Since the structure of a PE is simple and the same type PE executes the identical instructions, it is very suitable for VLSI implementation. The design process and correctness proof are considered in detail. Moreover, this algorithm can detect whether A is singular or not.