基于TMS320C6x实现多载波QPSK信号全数字化整体解调

提出并证明了一种群路FDMA/QPSK(频分多址/正交相移键控)信号全数字化整体解调的新方法,该方法根据信道构成特点和信号调制方式,将直接分路法和常规多相FFT(快速傅里叶变换)分离法相结合,构成了一种简化的等效多相FFT分路方法,再将输出的数字信号送到数字式解调器,实现了多载波信号的全数字化整体解调,其特点是软件和硬件结构简单、系统计算量小,且易于DSP实时实现,现已用该算法进行了32路FDMA/QPSK信号整体解调的计算机仿真实验,结果表明该方法是可行的.     

甲基化-β-环糊精的制备及其对甲基对硫磷和呋喃丹的增溶作用

研究了甲基化 β 环糊精(MCD)的一种简单制备方法及其对甲基对硫磷和呋喃丹的增溶作用。实验结果表明:MCD水溶液对甲基对硫磷和呋喃丹有明显增溶效果,在20g/L的MCD溶液中,甲基对硫磷和呋喃丹的溶解度比在纯水中分别提高了21 91和4 01倍,增溶作用的大小与MCD的浓度呈线性相关,而且和农药的疏水性及分子几何形状与环糊精空腔的匹配程度有关。     

速度-位置偏差耦合复合控制机电一体化仿真

四轴升降活动板系统运行时需要同步抬升并倾斜,受负载扰动后易产生姿态误差,为了避免姿态误差累积过多导致机械设备损坏,应当使用合适的位置同步控制策略。传统的位置偏差耦合控制受扰后产生的姿态误差较大,反应不够迅速。因此提出模糊增益调节的速度-位置偏差耦合复合控制方法,并在Matlab/Simulink中搭建了仿真模型进行负载扰动实验。实验结果表明该方法系统在起动和受负载扰动时产生的姿态误差小,消除速度快,比传统的位置偏差耦合控制同步性能更好。为了提前验证控制方法在设备上的效果,还建立了基于PLCSIM Advanced与MCD（Mechatronics Concept Design）的机电一体化仿真平台,测试结果表明:系统整体功能完善,活动板倾斜角速度稳定,姿态误差仅0.142°。     

激光雷达距离像相关跟踪中的图像预处理

相干激光雷达距离像预处理是获得最终图像必不可少的步骤,其处理的好坏直接关系到目标识别的正确与否及追踪的稳定性.本文首先通过基于相干激光雷达特性得到仿真激光雷达含噪距离像与强度像,进而对原始噪声图像进行了背景抑制与距离反常抑制(中值滤波)以及二者结合预处理.用基于MCD距离的相关算法对处理前、后图像进行追踪.最后给出跟踪绝对误差.     

MCD光纤电流差动保护动作后不能正常录波原因分析

详细叙述了早期投运的MCD光纤电流差动保护正确动作后不能正常录波的原因，提出了改进措施及提示。     

A predictive synchronizer for periodic clock domains

An adaptive predictive clock synchronizer for systems on chip incorporating multiple clock domains is presented. The synchronizer takes advantage of the periodic nature of clocks in order to predict potential conflicts in advance, and to conditionally employ an input sampling delay to avoid such conflicts. The result is conflict-free synchronization with maximal throughput and minimal latency. The adaptive predictive synchronizer adjusts automatically to a wide range of clock frequencies, regardless of whether the transmitter is faster or slower than the receiver. The synchronizer also avoids sampling duplicate data or missing any input. A novel method is presented for formal treatment of synchronizers and metastability. Correct operation of the synchronizer is formally proven and verified.     

Fast cross-validation of high-breakdown resampling methods for PCA

Cross-validation (CV) is a very popular technique for model selection and model validation. The general procedure of leave-one-out CV (LOO-CV) is to exclude one observation from the data set, to construct the fit of the remaining observations and to evaluate that fit on the item that was left out. In classical procedures such as least-squares regression or kernel density estimation, easy formulas can be derived to compute this CV fit or the residuals of the removed observations. However, when high-breakdown resampling algorithms are used, it is no longer possible to derive such closed-form expressions. High-breakdown methods are developed to obtain estimates that can withstand the effects of outlying observations. Fast algorithms are presented for LOO-CV when using a high-breakdown method based on resampling, in the context of robust covariance estimation by means of the MCD estimator and robust principal component analysis. A robust PRESS curve is introduced as an exploratory tool to select the number of principal components. Simulation results and applications on real data show the accuracy and the gain in computation time of these fast CV algorithms.     

Crystal field analysis of EuCl3.6H2O

Absorption and magnetic circular dichroism (MCD) spectra of polycrystalline EuCl₃.6H₂O samples were recorded between 16 000 and 36 000 cm⁻¹ at ambient temperature and at 77 K. A total of 104 crystal field transitions has been observed in the spectra. The MCD spectrum resembles the first derivative of the absorption spectrum, indicating the presence of (pseudo) A-terms. The advantage of MCD is the possibility of detecting quasi-degenerate crystal field levels, which are not resolved in the absorption spectrum. The coordination polyhedron around Eu³⁺ is a distorted square antiprism (C.N.=8). In order to make the crystal field calculations more tractable, the real C₂ symmetry of the europium site is approximated by a C_2v symmetry. The energy levels of the 4f⁶ configuration of Eu³⁺ are parametrized in terms of 20 free ion parameters and 9 B_q^k crystal field parameters. J-mixing is taken into account.     

Bayesian changepoint and time-varying parameter learning in regime switching volatility models

This paper proposes a combined state and piecewise time-varying parameter learning technique in regime switching volatility models using multiple changepoint detection. This approach is a Sequential Monte Carlo method for estimating GARCH & EGARCH based volatility models with an unknown number of changepoints. Modern auxiliary particle filtering techniques are used to calculate the posterior densities and online forecasts. This approach also automatically deals with the common ancestral path dependence problem faced in these type volatility models. The model is tested on Borsa Istanbul (BIST) formerly known as Istanbul Stock Exchange (ISE) market data using daily log returns. A full structural changepoint specification is defined in which all parameters of the conditional variance of the volatility models are dynamic. Finally, it is shown with simulation experiments that the proposed approach partitions the series into several regimes and learns the parameters of each regime's volatility model in parallel with the multiple changepoint detection process.     

PDM使新产品开发设计过程一体化

介绍了日本NEC移动通信分公司采用PDM系统,帮助行政管理部门与加工车间共享CAD数据.以较低的成本、更快的速度、更少的误差实现新产品的在线设计和开发.