传感器特性曲线的一种拟合方法

为了满足智能仪表开发的需求,同时减轻开发人员的繁重工作,提出了利用Matlab软件拟合传感器特性曲线的方法,用该方法迅速方便地建立传感器的数学模型。通过应用实例详细说明了建立传感器数学模型的步骤。最后得出结论:数学模型准确可用,利用Matlab软件拟合传感器特性曲线具有相当的实用价值。     

Bayesian approach to parameter estimation of the generalized pareto distribution

Several methods have been used for estimating the parameters of the generalized Pareto distribution (GPD), namely maximum likelihood (ML), the method of moments (MOM) and the probability-weighted moments (PWM). It is known that for these estimators to exist, certain constraints have to be imposed on the range of the shape parameter,k, of the GPD. For instance, PWM and ML estimators only exist fork>−0.5 andk≤1, respectively. Moreover, and particularly for small sample sizes, the most efficient method to apply in any practical situation highly depends on a previous knowledge of the most likely values ofk. This clearly suggests the use of Bayesian techniques as a way of using prior information onk. In the present work, we address the issue of estimating the parameters of the GPD from a Bayesian point of view. The proposed approach is compared via a simulation study with ML, PWM and also with the elemental percentile method (EPM) which was developed by Castillo and Hadi (1997). The estimation procedure is then applied to two real data sets.     

IP智能与WDM技术的融合

讨论了在IP over WDM directly分层结构下,IP层网络与光层网络的三种基本融合方式—静态重叠模型、动态重叠模型和动态对等模型,这三种融合方式体现了IP over WDM directly的演变过程。同时还对各种融合方式中网络的组成结构及相应的控制平面技术作了详尽的阐述。     

基于综合脉冲与孔径技术的多基地"无源"定位系统

本文根据综合脉冲／孔径雷达采用多个天线同时向全空域辐射多个载频信号,而在接收端通过信号处理获得发射方向图的特点,提出一种新的多基地“无源”定位雷达系统。该系统既利用在岩上发射,在舰船上接收而构成岩－舰多基地雷达,又由于在接收站不发射信号而相当于无源定位系统,本文介绍该系统的基本组成,工作原理及其与常规地波超视距雷达、双／多基地雷达相比的显著特点,给出计算机模拟结果;最后讨论了该雷达需解决的关键问题。     

Randomised hough transform with error propagation for line and circle detection

In this paper, we introduce a new Randomised Hough Transform aimed at improving curve detection accuracy and robustness, as well as computational efficiency. Robustness and accuracy improvement is achieved by analytically propagating the errors with image pixels to the estimated curve parameters. The errors with the curve parameters are then used to determine the contribution of pixels to the accumulator array. The computational efficiency is achieved by mapping a set of points near certain selected seed points to the parameter space at a time. Statistically determined, the seed points are points that are most likely located on the curves and that produce the most accurate curve estimation. Further computational advantage is achieved by performing progressive detection. Examples of detection of lines using the proposed technique are given in the paper. The concept can be extended to non-linear curves such as circles and ellipses. ID="A1"Correspondance and offprint requests to: Q. Ji, Department of Electrical, Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA. E-mail: qji@ecse.rpi.edu     

低压出线接地故障保护与保护电器--兼谈低压熔断器的应用

分析了ＴＴ和ＴＮ系统的接地故障保护和保护电器及其应用条件。在对比ＴＮ系统出线接地故障采用低压断路器和熔断器过电流保护的优缺点之后,认为重视廉价的电压熔断器的选用,并提出其应用条件和适用的装设场所。     

日本三菱350MW机组DEH的超速保护逻辑分析与简介

介绍了河津电厂两台 350MW机组的DEH超速保护系统 ,超速保护控制OPC ,机械超速保护MOST ,电超速保护EOST的工作原理和有关试验     

电力行业建立统一信息网的策略

为适应电力行业未来以数据业务为主的信息流,需要在融合现有以电路交换网为主体的通信网和以高速局域网为主体的计算机网基础上建立统一信息网。建立统一信息网在技术上可以借鉴ＩＰ ｏｖｅｒ ＡＴＭ技术,在组网策略上有重叠网策略和混合网策略两种选择。     

含多重累加函数的典型爆轰驱动模型不确定度分析方法

为了建立适用于含多重累加函数的爆轰驱动模型不确定度分析方法,选择了较为典型的圆筒试验模型进行了分析。针对原始数据获取、位移曲线拟合、膨胀速度及比动能计算等过程,讨论了影响各物理量测量不确定度的主要因素,并对多重累加函数拟合参数的不确定度评定模型进行了修正。同时,基于TNT和JO-159两种典型炸药的25mm圆筒试验结果,获得了比动能测量不确定度的变化规律,并详细分析了几类因素的影响程度。结果表明:圆筒比动能测量不确定度的最大影响因素是图像放大比的相对不确定度;随着圆筒比动能的增大,其标准不确定度近似呈线性增长,而相对不确定度在膨胀中后期则逐渐减小;对于大多数高能炸药的25mm圆筒试验,其圆筒比动能的相对扩展不确定度(k=2)不超过2%,且随着炸药作功能力的增强而下降。     

Liquid phase hydrogenation of furfural to biofuel over robust NiCu/Laponite catalyst: A study on the role of copper loading

Sustainable production of biofuel and chemical feedstock through catalytic hydrogenation has now received increased attention due to the expeditious depletion of crude oil. In the present investigation, we developed a cost-effective and base metal-based NiCu/Laponite catalyst for liquid-phase hydrogenation of furfural into fuel range components. The robust catalysts were prepared by a simple co-impregnation method with constant loading of 5 wt% NiO with different wt.% of CuO (x) loadings (where x = 8, 10, 12 & 14%) on the Laponite support. The textural properties, surface acidity, and reduction of the synthesized catalysts were studied by employing various physicochemical characterizations such as XRD, N₂ sorption analysis, NH₃-TPD, H₂-TPR, and TGA. The obtained results revealed that optimum loading of 12% CuO and 5% NiO catalyst aids fine dispersion of copper and nickel oxide on the surface of the support. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images displayed the delamination of Laponite particles and dispersion of Ni-Cu catalyst on the support surface. The hydrogenation efficiency of the synthesized catalysts was tested in a bench top stainless steel autoclave reactor by liquid phase reaction condition of furfural at 150–210 °C under 10–25 bar H₂ pressure for 1–6 h. The excellent activity of 5Ni-12Cu/Laponite catalysts was compared and correlated with the physicochemical characteristics of the catalyst.