基于FrFT和子空间正交的LFM信号参数估计

基于分数阶Fourier变换和子空间正交性,提出了一种低信噪比下线性调频信号检测与参数估计方法。讨论过程中将线性调频信号通过适当的分数阶Fourier变换得到一个单频复正弦信号,在此基础上,利用信号子空间与噪声子空间的正交性处理其正弦信号,再对线性调频信号的检测和参数估计转化为函数极值求解;最后,利用计算机模拟证实了方法的有效性。     

耦合腔行波管三维大信号程序设计

讨论了耦合腔行波管大信号互作用的物理模型和三维计算机程序设计，考虑了电子注的圆环模型在径向、轴向的速度以及圆环旋转的角速度，详细研究了电子注对场的激励形式、返波的影响和相对论修正等因素，编制出了耦合腔行波管三维大信号程序。计算结果与实际相符。     

Signal crimes and signal disorders: notes on deviance as communicative action

In this paper a 'signal crimes' perspective is outlined in an effort to unpack the relationships between experiences of crime and disorder, and perceptions of criminogenic risk. Grounded in symbolic interactionist sociology, and developing a social semiotic understanding of risk perception, it is a perspective that focuses upon processes of social reaction and the ways in which people interpret and define threats to their security. It is proposed that people interpret the occurrence of certain incidents as 'warning signals' about the levels of risk to which they are either actually or potentially exposed. These signals tend to take the form of signal crimes and/or signal disorders and are important in terms of how social space is symbolically constructed.     

校史教育在大学生核心价值观养成中的价值和途径

针对传统矿山定位监测系统中有线方式成本高、资源浪费、可操作性差等问题,将无线传感器网络技术应用于矿山微震定位。通讯系统采用由末端网络节点和中心节点构成的星形无线传感器网络结构。应用时钟同步技术,末端节点将矿震信号通过射频模块上传给中心节点,进而通过上位机完成对数据的进一步处理。该系统为无线通信在矿山越界开采监测中的应用研究。     

Variational Inference for Heteroscedastic Semiparametric Regression

We develop fast mean field variational methodology for Bayesian heteroscedastic semiparametric regression, in which both the mean and variance are smooth, but otherwise arbitrary, functions of the predictors. Our resulting algorithms are purely algebraic, devoid of numerical integration and Monte Carlo sampling. The locality property of mean field variational Bayes implies that the methodology also applies to larger models possessing variance function components. Simulation studies indicate good to excellent accuracy, and considerable time savings compared with Markov chain Monte Carlo. We also provide some illustrations from applications.     

数字信号处理双语教学教材选用与建设

研究了双语教学的教材选用和建设等问题,结合在北京邮电大学的双语教学实践就双语教学教材建设和使用提出了一些建议。     

DSP的通信协议栈的研究与实现

提出了一种基于TMS320C6415的嵌入式通信协议栈的实现方法。协议栈以TCP/IP/PPP为主,底层设计物理层协议,通过McBSP与信道调制解调的DSP进行数据帧收发,实现多DSP互连传输数据和物理信道状态通告;上层增加会话层,数据通过PCI总线接口与主机应用层协议进行通信,在DSP内部采用μC/OS-II完成多任务的调度管理。在Windows 2000上用Driver Studio设计实现cPCI的WDM驱动。实验结果表明,该协议栈具有结构紧凑、层次分明、传输速率高、回路延迟小的特点,符合设计要求。以之为基础开发的协议栈软件实现了远程测量通信。     

利用迭代滤波改进乘积高阶模糊函数

乘积高阶模糊函数(PHAF)是因分析mc-PPS而提出来的,但它抑制交叉项的能力有限,难以实现mc-PPS估计。该文提出了逐次滤除最强PHAF峰对应的分量来减少交叉项的迭代滤波方法,改进后的PHAF具有较好的鲁棒性:减少了估计盲区,并且具有更好的估计精度,降低了信噪比门限,而且能估计低阶相位系数,这些性能由多个mc-PPS仿真例子所验证。     

Single-step and multiple-step forecasting in one-dimensional single chirp signal using MCMC-based Bayesian analysis

Chirp signals are frequently used in different areas of science and engineering. MCMC-based Bayesian inference is done here for the purpose of one-step and multiple-step prediction in the case of the one-dimensional single chirp signal with iid error structure as well as dependent error structure with exponentially decaying covariances. We use Gibbs sampling technique and random walk MCMC to update the parameters. We perform total five simulation studies for the illustration purpose. We also do some real-data analysis to show how the method is working in practice.     

Approximating the projection depth median of dimensions p ⩾ 3

As a multivariate generalization of the univariate median, projection depth median (PM) is unique, and enjoys a very high breakdown point, much higher than its affine equivariant competitors such as halfspace depth median. Nevertheless, its computation is challenging. Until now PM can only be exactly computed efficiently for bivariate data. In this article, we develop an algorithm to approximate PM in higher dimensions. Some data examples indicate that the proposed algorithm performs well in terms of both accuracy and efficiency. As an application, we investigate the finite sample relative efficiency of PM by utilizing the Matlab implementation of this algorithm.