基于现时观测器的状态反馈调节系统CAD

针对使用现时观测器组成的状态反馈调节系统CAD,需对2n高阶方程及带符号变量二元矩阵方程组求解,线性代数或数值计算法难于实现,本文借助MATLAB控制系统工具箱和符号数学工具箱中有关函数,构成CAD的M文件,自动完成设计过程。计算结果与仿真数据比较,两者基本一致,证明此方法的正确性和实用性。     

基于符号对象函数的离散状态空间方程求解

针对Z变换求解离散状态空间方程,涉及符号变量和繁杂的数字运算,不能使用一般的数值计算法求解,提出借助MATLAB符号数字工具箱中有关符号对象函数构成M文件,自动完成求解过程,其结果与理论值比较,两者完全一致,证明此方法的正确性与实用性。     

全阶预估状态观测器调节系统的CAD

针对基于全阶预估状态观测器调节系统的CAD，需对带符号变量二元矩阵方程组求解，一般线性代数或数值计算法难于实现，提出借助MATLAB控制系统工具箱和符号数学工具箱中有关函数，编程解决了上述问题。理论计算与仿真结果比较，证明该方法的正确性和实用性。     

基于MATLAB符号数学工具箱的控制系统分析

介绍了用MATLAB6．1符号数学工具箱实现控制系统分析的一个通用算法。利用该算法可以求出系统的传递函数符号表达式及对系统状态方程进行求解，并给出解的符号表达式。该方法具有简便、直观、高效的特点。最后给出了一个应用实例。     

瑞利衰落信道上DF协作系统SER性能分析

对平坦瑞利衰落信道上解码转发(DF)中继协作系统的误符号性能进行了分析。利用矩生成函数(MGF)方法 ,推导出了该系统采用相干检测M进制相移键控(MPSK)时的平均误符号率(SER)的闭合表达式。数值计算结果表明了接收端平均信噪比(SNR)越大,DF中继协作系统误码性能越好。仿真结果证实了理论分析结果的正确性。     

基于视景仿真的航炮弹道仿真系统研究

根据航炮多体系统动力学计算结果和二维弹道数值计算方法，运用虚拟仿真技术建立了一套可完成弹道解算、仿真及射击精度分析的可视化演示平台。平台的构建过程中探索了虚拟场景中空间数字模型和碰撞模型的构建方法，用以更简洁、高效的驱动特定虚拟场景进行仿真。此平台可以引入动力学计算的结果．较为真实的仿真航炮射击实验现场，并演示炮弹飞行轨迹及结果。     

符号成形及SAW技术实现优化研究

本又提出利用声表面波（SWA）滤波器在载波上直接实现符号成形与调制。用切尾余弦系列作为基函数在连续相位，恒包络及附加谱分布字条件下对成形符号函数进行设计，并提出一种新的采样重构法优化设计此SAW调制滤波器，最后给出模拟结果并得出结论。     

一种应用于图像处理的水平集函数初始化方法

针对图像处理中,使用常规方法构造初始水平集函数难度大的问题,本文设计了一种基于多边形内外点判断计算符号距离函数的方法。通过对水平集曲线形状的分析,用多边形性质判别曲线内外点,求解点到曲线的符号距离。最后,给出了所设计方法的计算步骤和算例,并与常规方法进行了比较,结果表明,新的方法计算准确、收敛速度快。     

一种新的曲线演化混合模型图像分割算法

本文在Mumford-Shah模型的基础上，将传统几何曲线演化的驱动力（图像梯度局部信息）、Mumford-Shah模型的全局信息以及水平集的符号距离函数统一在一个变分框架之下，完成曲线演化过程的数值计算。本混合模型无需重新计算演化曲线的初始位置，可选择较大时间步长。实验结果表明，新的混合模型既保留了原有曲线演化模型的优势，又能高效稳健、快速地完成曲线演化过程。     

基于多符号分组的CPM软输出非相干检测算法

提出了一种CPM非相干检测算法,以连续多个符号为观测窗计算码字先验概率,以此完成CPM软解调计算操作,算法性能随着观测符号长度增加而提高。给出了非相干接收机结构,利用Walsh基函数扩展方法减少匹配接收计算量。仿真研究了不同CPM调制参数下卷积编码CPM系统非相干检测性能,结果表明,提出的非相干检测算法具有很好的顽健性,对于2CPM、4CPM串行级联编码调制,当观测长度为4个符号时,系统性能较单符号非相干检测算法有近6dB增益。     

Program state optimal method based on variable symbolic relation analysis

Program analysis is the prime method to program property analysis,which is widely used in the domain of parameter dependent relation,path coverage and test case generation,and a lot of progress has been made.Current program analysis is based on the method of symbolic execution,but symbolic execution is usually tackled with the problems of logic expression generation of path condition and low efficiency of constrain solver,which will affect the results of program analysis.Aiming at enhancing the path analysis efficiency,the path conditions of different paths were collected,the common symbolic expression was extracted and the efficiency of symbolic analysis was enhanced,then the logic expression set was generated,the dependent relation algorithm was used to enhance the efficiency of symbolic analysis.Experimental results demonstrate that the proposed method has the advantages of accurate time complexity and better analysis efficiency compare to traditional program analysis method.     

基于依赖条件重构的程序符号值分析方法

符号执行在路径分析、调试和验证等软件分析过程中发挥着重要的作用.但是随着程序规模的增大，有效的执行路径数量程指数级增长，符号执行技术往往难以有较好的分析效果.符号执行分析中的两个瓶颈问题是路径条件表达式的提取和约束求解.状态合并是目前解决状态爆炸的常用分析方法，但是这种抽象的分析方法往往会导致错误的路径信息.依据符号执行引擎采用的搜索策略，符号执行工具在符号变量状态合并中可能会产生不可解的路径条件.提出基于依赖条件重构的程序符号值分析方法，通过综合分析各路径的路径条件逻辑表达式，提取共享的变量符号值从而提高变量状态合并的效率，同时采用逆向关联分析方法产生依赖条件集合从而提高路径分析的精度.实验结果表明该方法相对于传统的状态合并分析方法有更高的执行效率及分析精度.     

开关功率变换器符号分析方法的原理

本文介绍了ＰＷＭ开关功率变换器的一种符号分析方法，着重阐述了该方法的一般原理，这一方法容易得到输出纹波的解析表达式以及系统的小信号模型，兼有计算过程简单和准确度较高的优点，可望成为功率电子学领域比较通用的一种方法。     

A hierarchical approach to large circuit symbolic simulation

This paper presents a new approach to symbolic analysis of large circuits. The proposed procedure is grounded on circuit decomposition by node tearing, symbolic analysis at subcircuit level and circuit function generation. Symbolic analysis is based on matrix-determinant method implemented within our original symbolic simulator. The crucial part of this procedure is circuit function generation. Opposed to classic symbolic simulation that gives final result in canonical sum-of-product form, hierarchical approach results in compact nested form. Proposed method is described in details using a simple example. The comparison with two other similar techniques is given using a benchmark example. The overall time reduction in comparison with the circuit function extraction in fully expanded form is 30 times.     

Enhanced Symbolic Simulation for Functional Verification of Embedded Array Systems

Symbolic simulation is an effective approach for verifying individual array blocks. This paper presents two methods to enhance the capacity of symbolic simulation for handling large and complex embedded array systems. The first method combines an ATPG decision procedure with symbolic simulation. By developing a scheme that enables the ATPG to work effectively with a symbolic simulator, the run-time OBDD sizes can be limited. In the second method, we propose a “dual-rail” symbolic simulator where a given design is partitioned implicitly into control and datapath domains. Symbolic simulation is carried out simultaneously on both domains. We demonstrate and compare the effectiveness of both methods based on verification of the Memory Management Unit (MMU) in Motorola high-performance microprocessors.     

Reduction of symbolic sparse matrices

A new general method is derived for reduction of linear systems of equations with symbolic polynomial coefficients suitable for using sparse matrix techniques. Its implementation in a program for symbolic analysis of circuits offers significant advantages over the existing reduction method.     

电路并行拓扑分析

提出了电路的并行拓扑分析法。该方法将节点撕裂法引入拓扑分析,完成对电路的并行处理,实现计算机对较大规模电路的并行符号分析,拓宽了符号分析法的应用"瓶颈",提高了符号分析的速度与效率。     

A new algorithm for computing the reliability of complex networks by the cut method

It is well known that computing network reliability is equivalent to computing network unreliability. A fusion of the reliability branching algorithm (RBA) with the path method has given a new method for symbolic reliability analysis. The present paper gives a new method for symbolic unreliability; it is a combination of the RBA with the cut method. The algorithm is simple for computing by hand and has easy execution for the use of computers.     

Symbolic Analysis of Switching Systems: Application to Bifurcation Analysis of DC/DC Switching Converters

A symbolic method is proposed in this paper for analyzing the bifurcation behavior of switching nonsmooth systems. The proposed method focuses on the symbolic sequence describing the topological change of the system which characterizes its bifurcation behavior. The concept of block sequence is first introduced. Based on the block sequence, the smoothness of the PoincarÉ map is described. Moreover, two main theorems are given to detect border collision and standard bifurcations. Finally, a specific example of the buck switching converter is presented to illustrate the application of the proposed symbolic analysis method. Using the proposed method, two-dimensional (2-D) bifurcation diagrams, which can assist engineers in identifying regions of preferred or undesired operations in the select parameter space, can be easily obtained.