Moments and root-mean-square error of the Bayesian MMSE estimator of classification error in the Gaussian model

The most important aspect of any classifier is its error rate, because this quantifies its predictive capacity. Thus, the accuracy of error estimation is critical. Error estimation is problematic in small-sample classifier design because the error must be estimated using the same data from which the classifier has been designed. Use of prior knowledge, in the form of a prior distribution on an uncertainty class of feature-label distributions to which the true, but unknown, feature-distribution belongs, can facilitate accurate error estimation (in the mean-square sense) in circumstances where accurate completely model-free error estimation is impossible. This paper provides analytic asymptotically exact finite-sample approximations for various performance metrics of the resulting Bayesian Minimum Mean-Square-Error (MMSE) error estimator in the case of linear discriminant analysis (LDA) in the multivariate Gaussian model. These performance metrics include the first, second, and cross moments of the Bayesian MMSE error estimator with the true error of LDA, and therefore, the root-mean-square (RMS) error of the estimator. We lay down the theoretical groundwork for Kolmogorov double-asymptotics in a Bayesian setting, which enables us to derive asymptotic expressions of the desired performance metrics. From these we produce analytic finite-sample approximations and demonstrate their accuracy via numerical examples. Various examples illustrate the behavior of these approximations and their use in determining the necessary sample size to achieve a desired RMS. The Supplementary Material contains derivations for some equations and added figures.     

一种用于金属安检门微弱信号处理电路的设计

针对金属安检门长期存在的误报、漏报问题,本设计采用了AD637真有效值转换、差动放大和窗口比较的微弱信号处理电路。改变峰值检测和模数转换的传统设计方式,利用差动放大器的对称性和两输入端时间常数不同达到抑制干扰的目的,通过带通滤波与窗口比较输出数字信号后,由单片机识别并报警。本设计可有效提高探测灵敏度,增强抗干扰能力,降低误报漏报率,并且降低成本。实测表明,本电路可探测30 cm范围内3 cm长铜丝。     

储层构造建模 --以h12沙三中4-8砂组建模为例

构造建模是储层建模中的关键一步,应该根据研究区块的地质体构造特征灵活设计建模方案,在建模过程中,应以丰富的地质工作经验为指导,适时进行必要的调整,如补点,断层线调整、奇异点调整等,以便做出的模型更加符合实际的地质情况。本文给出了一个实例,并就构造建模方案进行了初步讨论。     

A Simple Method of Radial Distortion Correction with Centre of Distortion Estimation

This paper presents a new simple method to determine the distortion function of camera systems suffering from radial lens distortion. Neither information about the intrinsic camera parameters nor 3D-point correspondences are required. It is based on single image and uses the constraint, that straight lines in the 3D world project to circular arcs in the image plane, under the single parameter Division Model. Most of former approaches to correct the radial distortion are based on the collinearity of undistorted points. The proposed method in this paper, however, is based on the conclusion that distorted points are concyclic and uses directly the distorted points not undistorted points, therefore it should be more robust. It also computes the centre of radial distortion, which is important in obtaining optimal results. The results of experimental measurements on synthetic and real data are presented and discussed.

飞机发动机振动测量仪的研制

介绍一种新型发动机振动测量仪的研制,该振动仪采用双路A／D采集,RMS均方根电路与频压转换电路实现振动位移的测量。目前,该仪器已应用于军用发动机测量。     

反应磁控溅射制备高阈值激光反射膜的研究进展

反应磁控溅射广泛应用于制备光学薄膜.分析了高阈值激光反射膜膜层材料的选择及膜系设计,比较了目前制备高阈值激光反射膜的几种常用方法.重点论述了反应磁控溅射制备高阈值激光反射膜需要解决的两个问题:工作点的选择及控制方法;反应磁控溅射中的打火、靶中毒及阳极消失.并且提出了相应的解决方案.阐述了影响激光反射膜损伤阈值的因素以及反应磁控溅射制备高阈值激光反射膜的优势.     

小信号测量系统的设计

介绍了采用ANALOG DEVICES＆的AD603实现的小信号测量系统，该系统增益范围是-20dB-60dB．系统带宽为60MHz。利用TLV5618实现了增益步进50级可调，用ADI公司的RMS-BC芯片AD637对输出信号的有效值进行了采集，井送LCD显示。     

应用于实时系统的RMS算法的改进

本文阐述了以PLC为核心的HGJD001实验台电气控制系统，并采用上位计算机实现对实验台运行状态的通讯监测。     

随机振动的特征表述和测量

本文介绍了正确表述随机振动特征的量 ,随机振动和一般周期振动的不同测量方法。     

基于RM S 误差分析的高光谱图像自动端元提取算法

提出了一种基于RM S ( root mean square) 误差分析的自动端元提取算法。对图像每做一次线性解混合, 就得到一幅以均方根RMS误差表示的残余误差图像, 从中选出误差较大的像素作为新的端元开始下一次解混合, 通过多次迭代, 直到得到了要求数目的端元。该算法克服了以往端元提取方法监督特性的局限, 减少了对先验信息的依赖, 同时保留了图像中的异常。利用仿真和实验数据验证了该算法的有效性。