认知无线电中基于循环统计量的频谱空穴检测方法

频谱空穴检测是认知无线电研究的关键技术.针对授权用户信号的循环平稳特性以及它和干扰信号、噪声的循环独立特性,提出了一种基于循环统计量的频谱空穴检测方案.构造了频谱空穴检测的二元假设检验模型,推导了相应的检验统计量.仿真结果表明,在低信噪比情况下,相比传统的能量检测法,该方法具有较优的检测性能,同时能有效地区分授权用户信号与同频干扰信号.     

油田企业物资部门计量管理不足及对策研究

结合现阶段企业物资部门计量管理实际,指出了在计量器具管理、检测方法标准文本配备、量值使用、检测需用外购物品管理、检验报告内部计量监管、检测设备利用等方面存在的不足,并有针对性地提出切实有效的改进对策,同时强调要通过重点宣贯和实施《用能单位能源计量器具配备和管理通则》国家标准,加强能源计量管理,为企业节能降耗见成效作贡献。     

Is the cardholder an efficient alarm system to detect credit card incidents?

There is a growing tendency in credit card industry to increase the contribution of the smallest players, the cardholders, in the detection of card incidents. This article examines whether cardholders are efficient at detecting/communicating incidents of theft, loss or fraudulent use of their cards. The analysis focuses on whether they demonstrate enough speed of response to support a risk control subsystem by the issuer. The research follows a completely new approach showing how the issue can be handled by applying the concept of elasticity, a notion just recently exported from economics to the field of statistics by linking it with the reverse hazard rate. The issue is focused on the analysis of the characteristics of the elasticity function of the random variable that measures the delay of cardholders in reporting incidents. This study is illustrated with an application to a real data set of 1069 incidents.     

一种适用于TD-SCDMA系统的多用户检测算法

利用逐次干扰抵消多用户检测结构,结合空时RAKE接收机,提出一种空时逐次干扰抵消多用户检测算法.仿真结果表明,该算法相比传统空时RAKE接收机有近5 dB的增益,误码率有了相当的改进.     

一种基于分数阶Fourier变换的雷达运动目标检测算法

针对雷达回波为多分量LFM信号时,时频分析存在的交叉项干扰问题,提出了一种基于分数阶Fourier变换(Fractional Fourier Transform,FRFT)的伪Wigner分布(PWD).该方法通过在参数平面按阈值进行峰值搜索确定变换域阶次,再在相应的分数阶Fourier域计算PWD,有效地抑制了交叉项的干扰,有利于更好地提取信号的时频信息.仿真实验证明了在强背景噪声下该算法的有效性.     

利用地质雷达方法进行重庆宝顶山-北山快速通道工程隧道灌浆检测

传统的地质雷达检测方法主要用于衬砌空洞及衬砌钢筋位置检测，对隧道灌浆状态及深度无法准确判断，不能适用于隧道衬砌后灌浆质量及深度的检测，为此，研究对传统地质雷达检测方法进行改进，通过灌浆孔内增设信号反射装置，在不影响灌浆施工的情况下，增强了雷达反射波，进而识别灌浆状态及深度，达到了对灌浆质量检测的目的。通过在宝棠隧道及龙岗隧道中的应用实例，检测结果证实了改进后的地质雷达探测方法可以对隧道衬砌及围岩灌浆状态进行判断，从而及时采取相应措施进行返工处理。     

基于Geortzel算法实现高效多路DTMF检测

基于戈泽尔算法，可得到一种DTMF检测的高效算法，本文描述了这种算法及使用该算法在TMS320S50上实现的30路DTMF检测器。     

基于视频图像的车辆检测算法研究

固定镜头下视频序列中的运动汽车目标的检测、分割、跟踪及计数等底层视觉问题进行了研究,提出了计算交通流量的算法。仿真实现表明:此算法可以有效的去噪、检测目标并计数。     

Estimators for the common principal components model based on reweighting: influence functions and Monte Carlo study

The common principal components model for several groups of multivariate observations is a useful parsimonious model for the scatter structure which assumes equal principal axes but different variances along those axes for each group. Due to the lack of resistance of the classical maximum likelihood estimators for the parameters of this model, several robust estimators have been proposed in the literature: plug-in estimators and projection-pursuit (PP) type estimators. In this paper, we show that it is possible to improve the low efficiency of the projection-pursuit estimators by applying a reweighting step. More precisely, we consider plug-in estimators obtained by plugging a reweighted estimator of the scatter matrices into the maximum likelihood equations defining the principal axes. The weights considered penalize observations with large values of the influence measures defined by Boente et al. (2002). The new estimators are studied in terms of theoretical properties (influence functions and asymptotic variances) and are compared with other existing estimators in a simulation study.     

滩海陆岸及油气开发人工岛发证检验中的设计审查质量控制

为保障海上石油设施生产作业、人员生命和财产安全，我国在滩海陆岸及油气开发人工岛石油作业中实行第三方发证检验制度。设计审查是发证检验的关键环节，介绍了设计审查过程中质量控制的主要内容。