线截抽样(LIS-Line Intersect Sampling)与线状物体(林网、路网)调查原理研究

以Ｂｕｆｏｎ随机投针问题为原理，对线截抽样的概念作了系统的介绍，并在此基础上提出了以线截抽样为原理的线状物体的调查方法。在计算机上成功地模拟了路网调查，从模拟的几种方案可以得出：线截抽样完全适用路网调查，且以本文中的Ｂ、Ｃ两种方案为好，并可以以此推广到林网及防护带的调查。

Determination of triazine herbicide residues in water samples by on-line sweeping concentration in micellar electrokinetic chromatography

A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.

Toward Estimating the Variance in Acoustic Surveys Based on Sampling Design

This paper develops a sampling method to estimate the integral of a function of the area with a strategy to cover the area with parallel lines of observation. This sampling strategy is special in that lines very close to each other are selected much more seldom than under a uniformly random design for the positions of the parallel lines. It is also special in that the positions of some of the lines are deterministic. Two different variance estimators are derived and investigated by sampling different man made signal functions. They show different properties in that the estimator that estimate the biggest variance gives an error interval that, in some situations, may be more than ten times the error interval computed from the other estimator. It is also obvious that the second estimator underestimates the variance. The author has not succeeded to derive an expression for the expectation of this estimator. This work is motivated towards finding the variance of acoustic abundance estimates.

ON-LINE ELECTROLYTIC DISSOLUTION OF SOLID METAL SAMPLE AND DETERMINATION OF COPPER IN ALLOY BY AAS

On-line dissolution of solid metal sample can be carried out by electrolysis under the control of flow injection analyzer(FIA),and the dissolved sample can be transferred to atomic spectrometer for the direct analysis.The hyphenated technique of FIA on-line electrolytic dissolution of alloy and atomic absorption spectrometer(AAS)detection is developed.The research is focused on the effects of electrolyte composition and electrolysis parameters on the sample dissolving,as well as the quantitative analysis of Cu in Al alloy samples.

Mapping and Comparative Analysis of QTL for Rice Plant Height Based on Different Sample Sizes within a Single Line in RIL Population

To clarify the most appropriate sample size for obtaining phenotypic data for a single line,we investigated the main-effect QTL(M-QTL) of a quantitative trait plant height(ph) in a recombinant inbred line(RIL) population of rice(derived from the cross between Xieqingzao B and Zhonghui 9308) using five individual plants in 2006 and 2009.Twenty-six ph phenotypic datasets from the completely random combinations of 2,3,4,and 5 plants in a single line,and five ph phenotypic datasets from five individual plants were used to detect the QTLs.Fifteen M-QTLs were detected by 1 to 31 datasets.Of these,qph7a was detected repeatedly by all the 31 ph datasets in 2006 and explained 11.67% to 23.93% of phenotypic variation;qph3 was detected repeatedly by all the 31 datasets and explained 5.21% to 7.93% and 11.51% to 24.46% of phenotypic variance in 2006 and 2009,respectively.The results indicate that the M-QTL for a quantitative trait could be detected repeatedly by the phenotypic values from 5 individual plants and 26 sets of completely random combinations of phenotypic data within a single line in an RIL population under different environments.The sample size for a single line of the RIL population did not affect the efficiency for identification of stably expressed M-QTLs.

DETERMINATION OF ANTIMONY IN WATER SAMPLES BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY WITH ON-LINE ION-EXCHANGE COLUMN PRECONCENTRATION

On-line ion-exchange separation and preconcentration were combined with flow-injection hydride generation atomic absorption spectrometry (HGAAS) to determine ultra-trace amounts of antimony in water samples. Antimony(Ⅲ) was preconcentrated on a micro-column packed with CPG-8Q chelating ion-exchanger using time-based sample loading and eluted by 4 mol l^(-1) HCl directly into the hydride generation AAS system. A detection limit (3σ) of 0.0015μg l^(-1) Sb(Ⅲ) was obtained on the basis of a 20 fold enrichment and with a sampling frequency of 60h^(-1). The precision was 1.0% r.s.d.(n=11) at the 0.5μg l^(-1) Sb(Ⅲ) level. Recoveries for the analysis of antimony in tap water, snow water and sea water samples were in the range 97-102%.

改进EDLines算法暨在高空输电线识别与巡检中的应用

针对无人机高空输电线实时巡线识别速度慢、精度低等问题,提出基于图像特征检测识别EDLines算法,以去除背景干扰提高输电线识别精度。通过改进锚点判定的方式搜索锚节点,搜索邻域梯度最大值作为绘制边缘的路径,利用随机抽样一致性(RANSAC)算法拟合直线段,以亥姆霍兹原理对虚假线段进行滤波处理,采用K均值聚类筛选出输电线特征直线,设计方向模板二次滤波定位输电线的位置。实验结果表明:本文算法识别输电线准确率提高,抗干扰能力增强,运行效率高,具有工程实践意义。

Sensitivity of Sample for Simulation-Based Reliability Analysis Methods

In structural reliability analysis,simulation methods are widely used.The statistical characteristics of failure probability estimate of these methods have been well investigated.In this study,the sensitivities of the failure probability estimate and its statistical characteristics with regard to sample,called‘contribution indexes’,are proposed to measure the contribution of sample.The contribution indexes in four widely simulation methods,i.e.,Monte Carlo simulation(MCS),importance sampling(IS),line sampling(LS)and subset simulation(SS)are derived and analyzed.The proposed contribution indexes of sample can provide valuable information understanding the methods deeply,and enlighten potential improvement of methods.It is found that the main differences between these investigated methods lie in the contribution indexes of the safety samples,which are the main factors to the efficiency of the methods.Moreover,numerical examples are used to validate these findings.

Study of Bacterial Samples Using Laser Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy （LIBS） technique has been applied to inves- tigate two different types of bacteria, Escherichia coli （B1） and Micrococcus luteus （B2） deposited on glass slides using Spectrolaser 7000. LIBS spectra were analyzed using spectrolaser software. LIBS spectrum of glass substrate was compared with bacteria spectra. Ca, Mg, Na, K, P, S, C1, Fe, A1, Mn, Cu, C, H and CN-band appeared in bacterial samples in air. Two carbon lines at 193.02 nm, 247.88 nm and one hydrogen line at 656.28 nm with intensity ratios of 1.9, 1.83 and 1.53 appeared in bacterial samples B1 and B2 respectively. Carbon and hydrogen are the important components of the bio-samples like bacteria and other cancer cells. Investigation on LIBS spectra of the samples in He and Ar atmospheres is also presented. Ni lines appeared only in B2 sample in Ar atmosphere. From the present experimental results we are able to show that LIBS technique has a potential in the identification and discrimination of different types of bacteria.

基于线结构光扫描的烟支表面缺陷检测方法研究

在烟支表面缺陷检测时,为解决传统二维图像方法无法获得深度信息的问题,提出一种基于线结构光传感器旋转扫描的检测方法。烟支在两同向辊轮的旋转带动下实现自转,通过线结构光视觉传感器获取物体轴向轮廓线,使用随机采样一致性拟合轮廓线,通过计算原始点到拟合轮廓的距离判断缺陷点。选取某品牌烟支在检测过程中得到的原始数据,其中多组样本的Kappa值均达到0.97,重复性达到99.3%。研究为烟支缺陷检测提供参考。

A Robust Model Fitting-based Method for Transmission Line Extraction from Airborne LiDAR Point Cloud Data

Airborne Light Detection And Ranging(LiDAR)can provide high-quality three-dimensional information for the safety inspection of electricity corridors.However,the robust extraction of transmission lines from airborne point cloud data is still greatly challenging.Therefore,this paper proposes a robust transmission line extraction method based on model fitting from airborne point cloud data.First,the candidate power line generation method based on height information is used to reduce the computational complexity at the subsequent steps and the false positives in the extracted results.Then,on the basis of the block-and-slice-constraint Euclidean clustering,a linear structure recognition method based on RANdom SAmple Consensus(RANSAC)is proposed to produce the initial individual transmission line components.Finally,a robust nonlinear least square-based fitting method is developed for the individual transmission line to generate the parameters of its mathematical model for further optimizing the extraction.Experiments were performed on LiDAR point cloud data captured from the helicopter and Unmanned Aerial Vehicle(UAV)platform.Results indicate that the proposed method can efficiently extract the different types of transmission lines along electricity corridors,with the average precision of approximately 98.1%,the average recall of approximately 95.9%,and the average quality of approximately 94.2%,respectively.

基于注意力网络集成的联机空中手写识别研究

针对联机空中手写识别的数据样本少、模型泛化能力不足、识别率低等问题,提出一种基于注意力网络集成的联机空中手写识别方法。该方法首先通过在形状特征中融入“联机”的时序特征,构建原始的多维数据;然后对多维融合数据降维投影到三个正交平面上,得到三组投影特征;其次,构建卷积神经网络用于提取视觉特征,同时引入字符嵌入作为图像的类标签,将类标签字符级语义特征通过注意力检测机制与三组视觉特征融合形成三组语义信息丰富的特征图,并基于特征图构建SoftMax分类器;最后,通过基于主学习器集成投票方法进行分类与识别。在两组空中手写数据集与哈工大(HIT-OR3C)联机数据上进行多组实验,在小样本的情况下,该方法识别率优于其他方法,分别达到95.68%,93.02%,94.96%。实验结果表明,该方法在小样本数据的情况下,充分发掘联机空中手写数据中有效特征,提高了空中手写识别效率。

基于机器视觉的电芯绝缘介质定位算法

为保证电芯绝缘介质定位的准确性和时效性,文章提出一种基于双线性插值亚像素坐标结合改进随机抽样一致性(random sample consensus,RANSAC)算法的绝缘介质定位算法。对工业采集的图像进行空间滤波、阈值分割等预处理操作,分割出目标并增强特征;运用Canny边缘检测算子检测边缘,选取定位轮廓并根据最小外接矩形分离4条边缘直线,用双线性插值公式精确定位边缘直线亚像素坐标;采用部分点先验模型约束RANSAC算法提取4条边缘直线的高质量内点,再用最小二乘法分别拟合4条边缘直线并计算出相应偏移量。实验结果表明,该算法能有效保证绝缘介质的定位精度且具有一定的时效性,可以较好地满足实际生产应用的要求。

一种监测母线槽的无线传感器信号采样策略

母线槽信号包含大量平稳信号和部分突发情况信号,完整准确地采集其信号能够保证母线槽的稳定运行。保持高上传率可准确地采集到信号,但功耗过大,降低设备使用寿命。文章提出一种适用母线槽信号的无线传感器节点近似采样策略(approximate sampling method,ASM),通过分析所采数据的相对变化程度及变化趋势捕捉完整突发情况信号,水塘抽样算法剔除部分无效平稳数据,完整准确地上传母线槽状态趋势信号。通过Matlab仿真表明ASM采样策略相比于SOD(send-on-delta)、无线传感器节点动态采样策略(dynamic sampling internal,DSI),无效采样率、变化偏移量更小,降低了能耗且保证了采样信号完整。

发电厂脱硫系统氯离子在线监测技术研究及应用

氯离子是发电厂脱硫系统的关键运行指标,快速准确监测脱硫浆液氯离子对脱硫设备防腐、运行工艺优化调整、脱硫废水排放及节水均具有重要意义。通过样品预处理的方法研发出了一种高效复合介质滤芯,及适用于脱硫系统样品预处理的方法,并进行了实验室实验;对脱硫系统氯离子在线测量方法原理进行研究,研制出了一种固态聚合膜氯离子选择性电极,研究出了一种发电厂脱硫系统氯离子在线监测技术,并进行了实验室准确性实验以及现场工业应用试验。结果表明:该脱硫系统氯离子在线监测技术能够实现脱硫浆液中氯离子的连续准确在线监测,大大减少了工作量,提高氯离子测量准确性,对实现脱硫系统设备的经济、智能化运行具有重要意义。

适用小样本的并网光伏阵列故障诊断方法

该文提出一种适用小样本的并网光伏阵列故障诊断方法。首先,使用光伏阵列的稳态输出电信号时间序列构建特征向量,论证该特征向量可以表征正常、开路故障、短路故障、阴影等不同状态。其次,针对光伏阵列运行环境多变的情况,提出一种将实际气象条件下光伏阵列输出值转换到统一工况下的数据处理方法。然后,为适用小样本情况,将线性判别分析方法与有偏差的协方差估计、公共奇异值分解相结合,解决样本高维低量导致的样本协方差矩阵估计奇异和判别函数求解困难的问题。最后,在上海市某高校楼顶搭建实验平台,采集光伏阵列不同状态下的实验数据,验证了所提数据处理方法对使用稳态电信号的必要性,及该故障分类算法在小样本场景中的有效性。

新一代帕洛马天文台光谱仪的虚拟刀口欠采样像质测量方法

天文光谱仪的成像质量可用点扩散函数或线扩散函数来表征,但其相对于光谱仪探测器通常为欠采样,很难直接测量。在新一代帕洛马天文台光谱仪的像质测试中引入虚拟刀口法进行光源物面扫描,并应用虚拟刀口法开展欠采样光谱仪像质及光源尺度测量,通过模拟和实验研究,对比分析过采样经典直边刀口法和过采样直接测量方法,验证了虚拟刀口法具有良好的测量精度。在693 nm处,直边刀口法测得光谱仪过采样线扩散函数的半高全宽为7.05μm,虚拟刀口法测量欠采样线扩散函数的半高全宽为7.14μm,测量误差为1.3%。在0.3"视场的光源尺度下,虚拟刀口法测得689、693、701 nm欠采样线扩散函数的半高全宽分别为24.2、27.7、30.8μm,以过采样直接测量结果为参考,其测量准确度分别为98.3%,93.9%和88.8%。实验结果表明,探测器成像严重欠采样时,采用光源物面扫描的虚拟刀口法可准确测量光谱仪的成像质量,该方法结合色散系数还可实现光谱仪分辨率的测量,相关研究工作可为天文光谱仪像质的直接测量提供借鉴。

Reliability and Sensitivity Analysis of Transonic Flutter Using Improved Line Sampling Technique

The improved line sampling （LS） technique, an effective numerical simulation method, is employed to analyze the probabilistic characteristics and reliability sensitivity of flutter with random structural parameter in transonic flow. The improved LS technique is a novel methodology for reliability and sensitivity analysis of high dimensionality and low probability problem with implicit limit state function, and it does not require any approximating surrogate of the implicit limit state equation. The improved LS is used to estimate the flutter reliability and the sensitivity of a two-dimensional wing, in which some structural properties, such as frequency, parameters of gravity center and mass ratio, are considered as random variables. Computational fluid dynamics （CFD） based unsteady aerodynamic reduced order model （ROM） method is used to construct the aerodynamic state equations. Coupling structural state equations with aerodynamic state equations, the safety margin of flutter is founded by using the critical velocity of flutter. The results show that the improved LS technique can effectively decrease the computational cost in the random uncertainty analysis of flutter. The reliability sensitivity, defined by the partial derivative of the failure probability with respect to the distribution parameter of random variable, can help to identify the important parameters and guide the structural optimization design.

Saddlepoint approximation based line sampling method for uncertainty propagation in fuzzy and random reliability analysis

For structural system with random basic variables as well as fuzzy basic variables,uncertain propagation from two kinds of basic variables to the response of the structure is investigated.A novel algorithm for obtaining membership function of fuzzy reliability is presented with saddlepoint approximation(SA)based line sampling method.In the presented method,the value domain of the fuzzy basic variables under the given membership level is firstly obtained according to their membership functions.In the value domain of the fuzzy basic variables corresponding to the given membership level,bounds of reliability of the structure response satisfying safety requirement are obtained by employing the SA based line sampling method in the reduced space of the random variables.In this way the uncertainty of the basic variables is propagated to the safety measurement of the structure,and the fuzzy membership function of the reliability is obtained.Compared to the direct Monte Carlo method for propagating the uncertainties of the fuzzy and random basic variables,the presented method can considerably improve computational efficiency with acceptable precision.The presented method has wider applicability compared to the transformation method,because it doesn't limit the distribution of the variable and the explicit expression of performance function, and no approximation is made for the performance function during the computing process.Additionally,the presented method can easily treat the performance function with cross items of the fuzzy variable and the random variable,which isn't suitably approximated by the existing transformation methods.Several examples are provided to illustrate the advantages of the presented method.

线聚焦谱域光学相干层析成像的分段色散补偿像质优化方法

本研究中搭建了一套用于生物样品成像的线聚焦谱域光学相干层析(LF-SD-OCT)系统,针对系统误差引起的轴向展宽和灵敏度衰减问题,提出了一种分段色散补偿的方法,对成像深度内的二阶和三阶色散相位进行了补偿,并通过平面镜和透明胶带样品成像实验来验证该方法的有效性和可靠性。通过本文提出的分段色散补偿方法和其他成熟方法的联合应用,系统在获得57.2 kHz的等效A-scan速率的同时,轴向分辨率提升至6.76μm,对胶带样品2 mm深度范围内及水果样品0.3 mm深度范围内进行了较清晰成像。实验结果表明,该方法可以在兼顾处理效率的同时提高全深度轴向分辨率和灵敏度,未来有望广泛实现线聚焦谱域光学相干层析的生物医学成像应用。